Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Biological Defense Research Program”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

106 records · Page 6Linked to original sources
PubMed2001

Abrogation of disease development in plants expressing animal antiapoptotic genes.

An emerging topic in plant biology is whether plants display analogous elements of mammalian programmed cell death during development and defense against pathogen attack. In many plant-pathogen interactions, plant cell death occurs in both susceptible and resistant host responses. For example, specific recognition responses in plants trigger formation of the hypersensitive response and activation of host defense mechanisms, resulting in restriction of pathogen growth and disease development. Several studies indicate that cell death during hypersensitive response involves activation of a plant-encoded pathway for cell death. Many susceptible interactions also result in host cell death, although it is not clear how or if the host participates in this response. We have generated transgenic tobacco plants to express animal genes that negatively regulate apoptosis. Plants expressing human Bcl-2 and Bcl-xl, nematode CED-9, or baculovirus Op-IAP transgenes conferred heritable resistance to several necrotrophic fungal pathogens, suggesting that disease development required host-cell death pathways. In addition, the transgenic tobacco plants displayed resistance to a necrogenic virus. Transgenic tobacco harboring Bcl-xl with a loss-of-function mutation did not protect against pathogen challenge. We also show that discrete DNA fragmentation (laddering) occurred in susceptible tobacco during fungal infection, but does not occur in transgenic-resistant plants. Our data indicate that in compatible plant-pathogen interactions apoptosis-like programmed cell death occurs. Further, these animal antiapoptotic genes function in plants and should be useful to delineate resistance pathways. These genes also have the potential to generate effective disease resistance in economically important crops.

Apoptosis↗
PubMed2004

A conserved transcript pattern in response to a specialist and a generalist herbivore.

Transcript patterns elicited in response to attack reveal, at the molecular level, how plants respond to aggressors. These patterns are fashioned both by inflicted physical damage as well as by biological components displayed or released by the attacker. Different types of attacking organisms might therefore be expected to elicit different transcription programs in the host. Using a large-scale DNA microarray, we characterized gene expression in damaged as well as in distal Arabidopsis thaliana leaves in response to the specialist insect, Pieris rapae. More than 100 insect-responsive genes potentially involved in defense were identified, including genes involved in pathogenesis, indole glucosinolate metabolism, detoxification and cell survival, and signal transduction. Of these 114 genes, 111 were induced in Pieris feeding, and only three were repressed. Expression patterns in distal leaves were markedly similar to those of local leaves. Analysis of wild-type and jasmonate mutant plants, coupled with jasmonate treatment, showed that between 67 and 84% of Pieris-regulated gene expression was controlled, totally or in part, by the jasmonate pathway. This was correlated with increased larval performance on the coronatine insensitive1 glabrous1 (coi1-1 gl1) mutant. Independent mutations in COI1 and GL1 led to a faster larval weight gain, but the gl1 mutation had relatively little effect on the expression of the insect-responsive genes examined. Finally, we compared transcript patterns in Arabidopis in response to larvae of the specialist P. rapae and to a generalist insect, Spodoptera littoralis. Surprisingly, given the complex nature of insect salivary components and reported differences between species, almost identical transcript profiles were observed. This study also provides a robustly characterized gene set for the further investigation of plant-insect interaction.

Animals↗
PubMedDate not supplied

Neutralizing innate host defenses to control viral translation in HSV-1 infected cells.

Lytic replication of many viruses activates an innate host response designed to prevent the completion of the viral lifecycle, thus impeding the spread of the infection. One branch of the host's complex reaction functions to incapacitate the cellular translational machinery on which the synthesis of viral polypeptides completely depends. This is achieved through the activation of specific protein kinases that phosphorylate eIF2 on its alpha subunit and inactivate this critical translation initiation factor. However, as continued synthesis of viral proteins is required to assemble the viral progeny necessary to transmit the infection to neighboring cells, viruses have developed a variety of strategies to counter this cellular response. Genetic and biochemical studies with herpes simplex virus type 1 (HSV-1) have revealed that the virus produces at least two discrete products at different times during its replicative program that act to prevent the accumulation of phosphorylated eIF2alpha. The gamma(1)34.5 gene product is expressed first, encoding a regulatory subunit that binds the cellular protein phosphatase 1alpha and regenerates pools of active eIF2 by removing the inhibitory phosphate from the alpha subunit. The second function, encoded by the product of the Us11 gene, specifies a double-stranded RNA-binding protein that prevents activation of PKR, a cellular eIF2alpha kinase. Together, both proteins cooperate to overcome the antiviral response of the host and properly regulate translation in HSV-1-infected cells.

Animals↗
PubMed1992

Alpha 2-macroglobulin, a multifunctional binding protein with targeting characteristics.

Alpha 2-macroglobulin (alpha 2M) and related proteins share the function of binding host or foreign peptides and particles, thereby serving as humoral defense barriers against pathogens in the plasma and tissues of vertebrates. In human alpha 2M, several reactive sites including high-affinity sites for zinc, transglutaminase cross-linking sites, and reactive sites derived from the activated thiol ester can mediate reversible or irreversible capture of proteins of diverse biological functions. Alpha 2M interacts and captures virtually any proteinase whether self or foreign, suggesting a function as a unique "panproteinase inhibitor." Activation of alpha 2M generates novel binding sites, which mediate complex formation with cytokines and other peptides. Direct evidence of physical association of cytokines with activated alpha 2M indicated its role as biological response modifier in cell cultures. A mechanism commonly referred to as "clearance of activated alpha 2M" involves Ca(2+)-dependent binding to a specific cell surface receptor, a member of the low-density lipoprotein receptor supergene family, that mediates cellular uptake by endocytosis and delivery to endosomes and lysosomes. The peptide binding function of alpha 2M, therefore, may also be viewed as a mechanism that allows targeting of biologically active peptides to different cell types expressing the alpha 2M receptor. Internalized complexes may be dispatched into different pathways of endocytic/lysosomal pathways in a cell type-specific manner. In addition, bioactive peptides bound to alpha 2M may dissociate in the process of intracellular ligand sorting, thereby modulating cell function, or remain bound and share the catabolic fate of alpha 2M. The diversified and probably programmed binding functions of alpha 2M indicate that in addition to its role in trapping proteinases, it has other biological activities that remain to be fully defined. That alpha 2M may function as a binding and carrier protein with targeting characteristics is predicted from 1) the known functions of alpha 2M, and 2) the similarity of the fate of alpha 2M with proteins whose significance in targeting and intracellular trafficking has been studied in more detail.

Animals↗
PubMed2003

Identification and functional clustering of global gene expression differences between human age-related cataract and clear lenses.

PURPOSE: Age-related cataract is a multi-factorial disease with a poorly understood etiology. Numerous studies provide evidence that the human eye lens has evolved specific regulatory and protective systems to ameliorate lens damage associated with cataract. Other studies suggest that the presence of cataract is associated with the altered expression of specific genes including metallothionein IIa, osteonectin, transglutaminase 2, betaig-h3, multiple ribosomal proteins, ADAM9, and protein phosphatase 2A. Here, we sought to identify further gene expression changes that are associated with cataract and to cluster the identified genes into specific biological pathways. METHODS: Oligonucleotide microarray hybridization was used to analyze the full complement of gene expression differences between lens epithelia isolated from human age-related cataract relative to clear lenses. The expression levels of a subset of the identified genes were further evaluated by semi-quantitative RT-PCR. The identified genes were functionally clustered into specific categories and the probability of over-representation of each category was determined using the computer program EASE. RESULTS: 412 transcripts were observed to be increased and 919 transcripts were observed to be decreased by 2 fold or more in lens epithelia isolated from age-related cataract relative to clear lenses. Of these, 74 were increased and 241 were decreased at the 5 fold level or greater. Seventeen genes selected for further confirmation exhibited similar trends in expression when examined by RT-PCR using both the original and separately prepared clear and cataract RNA populations. Functional clustering of the identified genes using the EASE bioinformatics software package revealed that, among others, transcripts increased in cataract are associated with transcriptional control, chromosomal organization, ionic and cytoplasmic transport, and extracellular matrix components while transcripts decreased in cataract are associated with protein synthesis, defense against oxidative stress, heat-shock/chaperone activity, structural components of the lens, and cell cycle control. CONCLUSIONS: These data suggest that cataract is associated with multiple previously identified and novel changes in lens epithelial gene expression and they point to numerous pathways likely to play important roles in lens protection, maintenance, and age-related cataract.

Aged↗
PubMed1997

The Cost of Biological Terrorism.

Most Americans are or will be facing a threat more real than crimes or terrorism-it is the threat of cancer. Indeed, one-fourth of all Americans alive today will ultimately die from cancer. Yet the level of funding for cancer research in 1998 and beyond remains in doubt. The Senate Appropriations Committee has proposed a higher funding figure than the House and the difference will be resolved in negotiations this September. President Clinton has recommended a meager 2.5% increase in spending on cancer. This sum is simply not enough. Although Americans may fool themselves into thinking the government has been at war against cancer, the current funding ceiling for the National Institutes of Health (NIH) budget demonstrates that this so-called offensive is little more than a skirmish. Careful scrutiny of this budget reveals that every time a citizen pays ten dollars in taxes, only one penny goes to cancer research. What the government is spending in cancer research would not buy or maintain two stealth bombers-hardly evidence of a major military strike. For those of us fighting the deadly scourge of cancer, the 1,550 Americans killed each day by this disease are painful and enduring casualties. Imagine five fully loaded jumbo jets crashing with no survivors on the same day. These headlines would generate fast and effective calls for funding for improved safety regulations, and yet cancer takes this number of lives daily-and in one year more lives than all the U.S. combat fatalities in this century. And yet there is a virtual silence as Congress meets to determine the level of monies to direct to cancer research efforts which might halt this carnage. In the past, medical research stopped the horrors of pain associated with amputations and operations conducted without anesthesia, and research stopped the epidemic of polio and the massive deaths from typhoid fever. Soon research will stop the deaths from AIDS. Will cancer be prevented or cured within your lifetime? It should and can be, but only if Americans speak up and demand Congress do its part to advance promising research by supporting NIH and efforts to control cancer. Cancer has stricken almost every family and we urgently need more defense. We must not sit waiting quietly any longer. It is time for a wake-up call to arms, to declare a war effort that demands results. The U.S. paid thirty times more for the Gulf War than the annual budget allotment for cancer research, and five times more to maintain the space program. Today, three-fourths of all cancer research grants approved by critical scientific review still go inactive. These instances represent more lost opportunities, more lost time, more lost lives. We must do better than this. Cancer strikes at the heart and fabric of our society. For the 1.3 million Americans diagnosed with cancer this year, the cost to our economy will exceed $100 billion. Thus, the $2.4 billion now being spent on research is insufficient medically and morally. Several clear-sighted congressional leaders who understand the critical need for increased funding have worked to assure expanded resources for the NIH and for cancer research. Unfortunately, their voices are too often drowned out by legislators with different agendas. Even with limited funds, America's past 25 years of cancer research has paid off. We have already cured some types of cancers, especially those that strike our young people. From 1973 to 1990, the cancer death rate from birth to 19 years of age decreased 38%; from 20 to 40 years, 20%; and from 45 to 54 years, 10%. Over this same period, the government invested $56 million on testicular cancer research. This effort yielded a 91% cure rate and produced an annual savings of $166 million that will last forever. The financial investment was repaid in six months, and the victims have an increased life expectancy of 40 years. These examples and others are proof of the principle that the support of cancer research pays off. However, we have not yet won such hard-fought victories on the more prevalent forms of cancers such as breast, prostate, and lung. Whether it is by cure or prevention, cancers must also be controlled and it can only be accomplished through research. On December 23, 1971, President Richard Nixon signed the National Cancer Act that was to provide, ".a total commitment of Congress and the president. to provide the funds. for the conquest of cancer." Somewhere this contract with America got lost. We are now faced with more losses. The new upheaval in American medicine threatens clinical research in cancer investigation to test new therapies and to support the training of new research soldiers to join the battle. The bottom-line approach of insurance and managed care policies no longer cares about these essential components; they say it is no longer their responsibility. This loss of financial support, combined with the tepid endorsement of funding of research from the government, occurs just when there is an explosion of new discoveries and opportunities becoming available to attack cancer. It is time to dramatically increase our efforts and no time to retreat. If we really want to defend against the terrorism of cancer, we need to attack it with a real war effort. If we can go to Mars, we can go to war on cancer, but only if Americans can speak louder than their elected government leaders. They need to hear our opinion, now.

Journal Article↗
PubMed2005

The diphenylether herbicide lactofen induces cell death and expression of defense-related genes in soybean.

Lactofen belongs to the diphenylether class of herbicides, which targets protoporphyrinogen oxidase, which in turn causes singlet oxygen generation. In tolerant plants like soybean (Glycine max), the chemical nonetheless causes necrotic patches called "bronzing" in contact areas. Here it is shown that such bronzing is accompanied by cell death, which was quantified from digital microscopic images using Assess Software. Cellular autofluorescence accompanied cell death, and a homolog of the cell death marker gene, Hsr203j, was induced by lactofen in treated soybean tissues. Thus, this form of chemically induced cell death shares some hallmarks of certain types of programmed cell death. In addition to the cell death phenotype, lactofen caused enhanced expressions of chalcone synthase and chalcone reductase genes, mainly in the exposed and immediately adjacent (proximal) cells. Furthermore, isoflavone synthase genes, which are wound inducible in soybean, were up-regulated by lactofen in both proximal and distal cell zones in minimally wounded cotyledons and further enhanced in wounded tissues. Moreover, if the wall glucan elicitor from Phytophthora sojae was present during lactofen treatment, the induction of isoflavone synthase was even more rapid. These results are consistent with the fact that lactofen triggers massive isoflavone accumulations and activates the capacity for glyceollin elicitation competency. In addition, lactofen induces late expression of a selective set of pathogenesis-related (PR) protein genes, including PR-1a, PR-5, and PR-10, mainly in treated proximal tissues. These various results are discussed in the context of singlet oxygen-induced responses and lactofen's potential as a disease resistance-inducing agent.

Base Sequence↗
PubMed2005

Uncoupling proteins 2 and 3 function in concert to augment tolerance to cardiac ischemia.

Transient cardiac ischemia activates cell survival signaling, conferring subsequent ischemia tolerance to the heart. This biological phenomenon, termed ischemic preconditioning, results in improved clinical outcome and attenuated infarct size following myocardial infarction. To explore genomic modifications underpinning this ischemia tolerance, we delineated the regulation and function of the cardiac enriched mitochondrial uncoupling proteins 2 and 3 during delayed ischemic preconditioning in the rat. Cardiac transcripts of genes encoding uncoupling proteins 2 and 3 are up-regulated in parallel with infarct size reduction in preconditioned hearts. Mitochondria isolated from preconditioned hearts exhibit an augmented inducible proton leak. In parallel, following anoxia-reoxygenation these mitochondria generate less hydrogen peroxide compared with non-preconditioned mitochondria. Preconditioning in rat cardiac derived myoblasts is abolished following uncoupling protein-2 depletion by RNA-interference. RNAi of uncoupling protein-3 partially attenuates the capacity to precondition these cells. Functional characterization of anoxia and reoxygenation tolerance following uncoupling protein 2 or 3 and combined 2 and 3 RNAi shows the largest reduction in viability follows depletion of both homologues. Uncoupling protein-2 depletion alone significantly attenuates anoxia-reoxygenation tolerance but uncoupling protein-3 depletion does not reduce anoxia tolerance. In parallel combined uncoupling protein depletion and isolated uncoupling protein-2 depletion augments ROS production in viable cardiomyocytes following anoxia-reoxygenation. Concurrent anti-oxidant administration ameliorates the uncoupling protein-depleted anoxia-susceptible phenotype. In conclusion, mitochondrial uncoupling proteins are necessary components of ischemia tolerance and function as components of the cellular antioxidant defense program. In the cytoprotective hierarchy, uncoupling protein-2 appears to play a greater role than uncoupling protein-3 in modulating ischemia/anoxia tolerance in heart-derived cells.

Animals↗
PubMed2001

Opportunities for using Navy marine mammals to explore associations between organochlorine contaminants and unfavorable effects on reproduction.

The Department of Defense (DoD) has a unique marine mammal program maintained by the US Navy that includes the largest force of bottlenose dolphins, Tursiops truncatus, worldwide. In recent years, this population of cetaceans that lives in netted open water enclosures in San Diego Bay has been monitored for levels of organochlorine (OC) contaminants in blubber, blood and milk. Data generated from these studies have afforded insight into the fate and possible effects of OC contaminants in marine mammals. We now report preliminary findings on the effects of maternal OC exposure on pregnancy outcome. Blubber OC levels were compared between females whose calves survived beyond 6 months and females whose calves were stillborn or died within 12 days of birth. The mean concentration of SigmaDDT was more than 3 times as high among dolphins whose calves died as that among dolphins whose calves survived beyond 6 months (P = 0.002). Mean SigmaPCB was more than 2.5 times higher in females whose calves did not survive (P= 0.076). This population is a logical sentinel for the assessment of environmentally mediated disease. Biological tissues and fluids can be sampled on a regular basis from the dolphins for accumulation of tissue residues, facilitated by conditioned husbandry behaviors. These trained behaviors help preclude possible alterations in health measures resulting from capture stress. Animals' diets can be monitored for contaminant levels. With these data, the expertise and facilities available at the Navy laboratory and in collaboration with other experts in the field, controlled studies can be designed to monitor and assess dietary exposure, measurable immune and neurologic responses and assess reproductive and transgenerational effects of contaminants. Biomarkers can be developed to relate the health of individual animals relative to contaminant exposures. Such investigations of natural exposure and response scenarios are a logical adjunct to traditional laboratory toxicity studies.

Adipose Tissue↗
PubMed2003

Evolutionary analysis reveals collective properties and specificity in the C-type lectin and lectin-like domain superfamily.

Members of the C-type lectin/C-type lectin-like domain (CTL/CTLD) superfamily share a common fold and are involved in a variety of functions, such as generalized defense mechanisms against foreign agents, discrimination between healthy and pathogen-infected cells, and endocytosis and blood coagulation. In this work we used ConSurf, a computer program recently developed in our lab, to perform an evolutionary analysis of this superfamily in order to further identify characteristics of all or part of its members. Given a set of homologous proteins in the form of multiple sequence alignment (MSA) and an inferred phylogenetic tree, ConSurf calculates the conservation score in every alignment position, taking into account the relationships between the sequences and the physicochemical similarity between the amino acids. The scores are then color-coded onto the three-dimensional structure of one of the homologous proteins. We provide here and at http://ashtoret.tau.ac.il/ approximately sharon a detailed analysis of the conservation pattern obtained for the entire superfamily and for two subgroups of proteins: (a) 21 CTLs and (b) 11 heterodimeric CTLD toxins. We show that, in general, proteins of the superfamily have one face that is constructed mostly of conserved residues and another that is not, and we suggest that the former face is involved in binding to other proteins or domains. In the CTLs examined we detected a region of highly conserved residues, corresponding to the known calcium- and carbohydrate-binding site of the family, which is not conserved throughout the entire superfamily, and in the CTLD toxins we found a patch of highly conserved residues, corresponding to the known dimerization region of these proteins. Our analysis also detected patches of conserved residues with yet unknown function(s).

Amino Acid Sequence↗
PubMed1995

Depression of synaptic connections between identified motor neurons in the locust.

1. The fast extensor tibiae motor neuron makes direct excitatory central connections with the posterior group of flexor tibiae motor neurons in the locust metathoracic ganglion. The flexor group has a slow, a fast, and an intermediate motor neuron. The motor neurons are involved in the motor program for kicking and jumping, the defensive and escape behaviors of the locust. An antidromic action potential in fast extensor tibiae motor neuron (FETi) results in a monosynaptic, glutamatergic excitatory postsynaptic potential (EPSP) in each of the flexor motor neurons. 2. A train of 10 antidromic spikes in FETi at frequencies of 1-20 Hz resulted in depression of the amplitude of the EPSP in each of the flexor motor neurons. The depression was not significantly different in the different flexor motor neurons. The depression was greater with higher frequency stimulation and was reduced in low calcium saline. 3. After stimulation at 20 Hz, the EPSP amplitude was depressed by approximately 80%. This did not change when the number of stimuli was increased to 20, when stimulation was done in high calcium saline, or when the frequency of stimulation was increased to 50 or 100 Hz. The recovery from depression was greater after 20-Hz stimulation than at lower frequencies, although the recovery was reduced when the number of stimuli was increased, and also in high calcium saline. 4. In normal saline the depression of the EPSP amplitude was associated with a reduction of the presynaptic spike amplitude at frequencies of > or = 5 Hz. In tetraethylammonium (TEA) saline the width of a TEA-broadened spike was also reduced. The reduction in spike amplitude and spike width correlated with the depression of the EPSP. 5. Certain of these results are consistent with a depletion model of synaptic depression, whereas others are not consistent with this model. The depression may be partly due to an initial depletion of transmitter stores, and partly to modulation of the presynaptic action potential that reduces calcium entry, and therefore transmitter release. The significance of the depression on the motor program for kicking and jumping is discussed.

Animals↗
PubMed2001

Thymic T-cell tolerance of neuroendocrine functions: physiology and pathophysiology.

Intimate interactions between the two major systems of cell-to-cell communication, the neuroendocrine and immune systems, play a pivotal role in homeostasis and developmental biology. During phylogeny as well as during ontogeny, the molecular foundations of the neuroendocrine system emerge before the generation of diversity within the system of immune defenses. Before reacting against non-self infectious agents, the immune system has to be educated in order to tolerate the host molecular structure (self). The induction of self-tolerance is a multistep process that begins in the thymus during fetal ontogeny (central tolerance) and also involves anergizing mechanisms outside the thymus (peripheral tolerance). The thymus is the primary lymphoid organ implicated in the development of competent and self-tolerant T-cells. During ontogeny, T-cell progenitors originating from hemopoietic tissues (yolk sac, fetal liver, then bone marrow) enter the thymus and undergo a program of proliferation, T-cell receptor (TCR) gene rearrangement, maturation and selection. Intrathymic T-cell maturation proceeds through discrete stages that can be traced by analysis of their cluster differentiation (CD) surface antigens. It is well established that close interactions between thymocytes (pre-T-cells) and the thymic cellular environment are crucial both for T-cell development and for induction of central self-tolerance. Particular interest has focused on the ability of thymic stromal cells to synthesize polypeptides belonging to various neuroendocrine families. The thymic repertoire of neuroendocrine-related precursors recapitulates at the molecular level the dual role of the thymus in T-cell negative and positive selection. Thymic precursors not only constitute a source of growth factors for cryptocrine signaling between thymic stromal cells and pre-T-cells, but are also processed in a way that leads to the presentation of self-antigens by (or in association with) thymic major histocompatibility complex (MHC) proteins. Thymic neuroendocrine self-antigens usually correspond to peptide sequences highly conserved during the evolution of their corresponding family. The thymic presentation of some neuroendocrine self-antigens does not seem to be restricted by MHC alleles. Through the presentation of neuroendocrine self-antigens by thymic MHC proteins, the T-cell system might be educated to tolerate main hormone families. More and more recent experiments support the concept that a defect in thymic tolerogenic function is implicated as an important factor in the pathophysiology of autoimmunity.

Animals↗
PubMedDate not supplied

Instrument development and evaluation of domestic preparedness training for first responders.

INTRODUCTION: In the wake of domestic terrorists attacks on 11 September 2001 and subsequent bioterrorist events employing anthrax, there no longer can be any debate about the potential for attacks employing Nuclear, Biological, or Chemical (NBC)/Weapons of Mass Destruction (WMD). As one way of acknowledging this long-standing threat and, in a concerted effort to mitigate the effects of possible future domestic NBC/WMD terrorist attacks, the US Department of Defense (DOD) and other US governmental agencies already had mounted an effort to provide Domestic Preparedness Training for First Responders in urban centers throughout the USA. METHODS: A paper and pencil questionnaire specifically designed to evaluate the effectiveness of Domestic Preparedness Training for Emergency First Responders has been developed. An earlier version of this instrument was piloted with a convenience sample of firefighters and paramedics (n = 78) in a northwest state. Based on replies to the pilot questionnaire, a pool of 27 items based on the objectives and content of the NBC/WMD Domestic Preparedness Awareness and Operations courses (plus additional background and appraised competency items) were selected for inclusion in a Domestic Preparedness Questionnaire (DPQ). RESULTS: This paper first describes the essential psychometric properties of the DPQ based on replies from baseline and follow-up samples (n = 206 and n = 246 respectively) of urban firefighters and paramedics employed by a metropolitan city in a northwest state. The DPQ was employed to evaluate the outcomes of Domestic Preparedness training provided to a sample of urban fire-service personnel. The DPQ documented significant improvements in a group of "DP trained"-urban firefighters (n = 80) both in their awareness and operations content knowledge as well as in their perceived competencies to respond to acts of biological, chemical, or nuclear terrorism "in their own community" at four months post-training. A comparison group of "Not DP-trained" firefighters (n = 78) showed no statistically significant changes on these DPQ indices, suggesting that the documented improvements in the "DP-trained" firefighters on the DPQ were not due to "test reactivity" or to "historical" factors. CONCLUSION: The findings suggest that the DPQ has adequate inter-item and test-retest reliability, possesses concurrent validity, and appears to be a sensitive measure of the Domestic Preparedness Training provided for urban firefighter and paramedic First Responders.

Bioterrorism↗
PubMed2003

Crystal structures of pinoresinol-lariciresinol and phenylcoumaran benzylic ether reductases and their relationship to isoflavone reductases.

Despite the importance of plant lignans and isoflavonoids in human health protection (e.g. for both treatment and prevention of onset of various cancers) as well as in plant biology (e.g. in defense functions and in heartwood development), systematic studies on the enzymes involved in their biosynthesis have only recently begun. In this investigation, three NADPH-dependent aromatic alcohol reductases were comprehensively studied, namely pinoresinol-lariciresinol reductase (PLR), phenylcoumaran benzylic ether reductase (PCBER), and isoflavone reductase (IFR), which are involved in central steps to the various important bioactive lignans and isoflavonoids. Of particular interest was in determining how differing regio- and enantiospecificities are achieved with the different enzymes, despite each apparently going through similar enone intermediates. Initially, the three-dimensional x-ray crystal structures of both PLR_Tp1 and PCBER_Pt1 were solved and refined to 2.5 and 2.2 A resolutions, respectively. Not only do they share high gene sequence similarity, but their structures are similar, having a continuous alpha/beta NADPH-binding domain and a smaller substrate-binding domain. IFR (whose crystal structure is not yet obtained) was also compared (modeled) with PLR and PCBER and was deduced to have the same overall basic structure. The basis for the distinct enantio-specific and regio-specific reactions of PCBER, PLR, and IFR, as well as the reaction mechanism and participating residues involved (as identified by site-directed mutagenesis), are discussed.

Amino Acid Sequence↗
PubMedDate not supplied

[Armenia: implementation of national program of malaria control].

Malaria has been existing in Armenia since antiquity. In the 1920"s to 1930s, thousands of people suffered from this disease in the country. Enormous efforts were required to prevent further spread of the disease. A network was set up, which consisted of a research institute and stations. A total of 200,000 cases of malaria were still notified in 1934. Rapid development of the health infrastructure and better socioeconomic conditions improved the malaria situation and reduced the number of cases in 1946. Malaria was completely eradicated in Armenia in 1963, and the malaria-free situation retained till 1994. During that period, comprehensive activities were undertaken in the country to prevent and control malaria. Since 1990, following the collapse of the Soviet Union, the situation became critical in many newly independent states. Economic crisis, human migration, worsening levels of health services, and the lack of necessary medicines, equipment, and insecticides significantly affected the malaria epidemiological situation in the country. Malaria cases started to penetrate into Armenia from neighboring countries. In 1994, a hundred ninety six military men contacted malaria in Karabakh, which was unfavorable in terms of malaria, as well on as the border with Iran and along the Araks river. The first cases recorded in Armenia were imported, afterwards they led to the incidence of indigenous cases, given the fact that all the prerequisites for malaria mosquito breeding and development were encountered in 17 regions and 3 towns of the country. In 1995, there were 502 imported cases and in 1996 the situation changed: out of 347 registered cases, 149 were indigenous. The Ministry of Health undertook a range of preventive measures. In 1997 versus 1996, the total number of malaria cases increased 2.3-fold: 841 registered cases of which 567 were indigenous (a 3.8-fold increase). The overwhelming majority of cases were recorded in the Ararat and Armavir marzes. In 1998, there were a total of 1156 cases, of them 542 being locally contacted. The situation became stable thanks to joint efforts of WHO, IFRX, the Armenian Red Cross Society, UNICEF, the Ministry of Health of Armenia and its Government. Under Minister's Decree No. 292 of May 17, 1999, a malaria project implementation office was established in the Masis Sanitary and Epidemiological Surveillance Center of Hygienic and Antiepidemic Surveillance to improve progress of the malaria control programme in Armenia. WHO allocated some 7,700 USD for 5-month maintenance and work of the office. Thus, analyzing the malaria cases registered in 1999 and 1998 indicates a 1.9-fold decrease (616/77). The setting up the malaria programme field office under the Minister's decree was instrumental in planning and implementing activities in situ. In 1999, four cases of tropical malaria were recorded in Armenia. The patients were Armenian pilots who contacted malaria during duty travels: 1 in Sudan and 3 in Congo. The list of pilots making flying to endemic countries was submitted to the Republican Center to implement preventive measures in the future. In Armenia malaria surveillance has been improved to ensure timely detection of all suspected cases and to carry out malaria control activities. In this regard, a seminar was held for 21 entomologists and 12 parasitologists. UNICEF and WHO Armenian offices provided a substantial support to organize seminars. To facilitate the seminars, the manual "Malaria parasitology and entomology" was published and distributed among their participants. On April 19, 1999, the session of the Ministry's Executive Board (Collegium) gave recommendations to reinforce malaria control activities in the country. Decrees No. 256 of May 31, 1999, No. 47 of May 29, 1999, and No. 245 of April 30, 1999, "On malaria and preventive and control activities" were issued by the Ministry of Health, the Ministry of Defense, and the Ministry of Internal Affairs and National Security to serve as a guideline for planning and implementing activities. The Ministry of Agriculture undertook to clean the collective irrigation (drainage) system covering 102 and 77 km in the Ararat and Armavir marzes, the Ministry of Health provided a list of endemic foci where cleaning was a priority. Taking into account the importance of the people's participation in ensuring effective prevention and control, emphasis was laid on health education activities: publication of leaflets, as well as articles in local newspapers, radio broadcasts and TV shows. Throughout the season, the early detection of malaria cases, timely hospitalization (in no later than 1-3 days) for at least 5 days and subsequent treatment under direct supervision of a physician were successfully carried out due to home-to-home visits. Entomological studies conducted in the malaria foci show an increase in the presence and density of a malaria vector in the buildings. As far as treatment is concerned, the overall surface of stagnant waters comprised 2642 ha in 1999 (2733 ha in 1998), including 1285 ha of anophelogenic stagnant waters (2276 ha in 1998). The biggest stagnant water surfaces were in the Ararat and Armavir marzes--2209 ha, where the majority of malaria cases were recorded. A total of 1,283,111 and 559,213 sq. m. of constructions were treated in 1999 and 1998, respectively, out them there were 1,259,637 sq. m. in 5 endemic regions. Stagnant water surfaces were treated with bacticulicides on 250.7 and 743.8 (almost 3 times more) in 1998 and 1999, respectively. In 1999, 740 ha of surface were biologically treated using Gambusia compared to 900 ha treated in 1998. There is no highly qualified diagnostic specialists in many regions of the country, which necessitates the holding of further seminars involving relevant specialists, in all malaria regions. There is a tendency of geographical spread of malaria: malaria cases occur in new regions and dwellings. A country-wide action plan was drafted for 2000, mainly focusing on staff training. With WHO assistance, a seminar was held for 324 specialists from endemic regions. During the first quarter of 2000, 13 cases of tertian malaria were recorded as compared 59 cases during the same period of last year. All these patients contacted malaria in the previous season and demonstrated long incubation periods. Thus, the malaria control plan recommended by WHO and the rational and targeted use of its assistance has shown a 2-fold decrease in the incidence of malaria.

Armenia↗
PubMed2005

Thymic commitment of regulatory T cells is a pathway of TCR-dependent selection that isolates repertoires undergoing positive or negative selection.

The seminal work of Le Douarin and colleagues (Ohki et al. 1987; Ohki et al. 1988; Salaun et al. 1990; Coutinho et al. 1993) first demonstrated that peripheral tissue-specific tolerance is centrally established in the thymus, by epithelial stromal cells (TEC). Subsequent experiments have shown that TEC-tolerance is dominant and mediated by CD4 regulatory T cells (Treg) that are generated intrathymically by recognition of antigens expressed on TECs (Modigliani et al. 1995; Modigliani et al. 1996a). From these and other observations, in 1996 Modigliani and colleagues derived a general model for the establishment and maintenance of natural tolerance (MM96) (Modigliani et al. 1996b), with two central propositions: (1) T cell receptor (TCR)-dependent sorting of emergent repertoires generates TEC-specific Treg displaying the highest TCR self-affinities below deletion thresholds, thus isolating repertoires undergoing positive and negative selection; (2) Treg are intrathymically committed (and activated) for a unique differentiative pathway with regulatory effector functions. The model explained the embryonic/perinatal time window of natural tolerance acquisition, by developmental programs determining (1) TCR multireactivity, (2) the cellular composition in the thymic stroma (relative abundance of epithelial vs hemopoietic cells), and (3) the dynamics of peripheral lymphocyte pools, built by accumulation of recent thymic emigrants (RTE) that remain recruitable to regulatory functions. We discuss here the MM96 in the light of recent results demonstrating the promiscuous expression of tissue-specific antigens by medullary TECs (Derbinski et al. 2001; Anderson et al. 2002; Gotter et al. 2004) and indicating that Treg represent a unique differentiative pathway (Fontenot et al. 2003; Hori et al. 2003; Khattri et al. 2003), which is adopted by CD4 T cells with high avidity for TEC-antigens (Bensinger et al. 2001; Jordan et al. 2001; Apostolou et al. 2002). In the likelihood that autoimmune diseases (AID) result from Treg deficits, some of which might have a thymic origin, we also speculate on therapeutic strategies aiming at selectively stimulating their de novo production or peripheral function, within recent findings on Treg responses to inflammation (Caramalho et al. 2003; Lopes-Carvalho et al., submitted, Caramalho et al., submitted). In short, the MM96 argued that natural tolerance is dominant, established and maintained by the activity of Treg, which are selected upon high-affinity recognition of self-ligands on TECs, and committed intrathymically to a unique differentiative pathway geared to anti-inflammatory and antiproliferative effector functions. By postulating the intrathymic deletion of self-reactivities on hemopoietic stromal cells (THC), together with the inability of peripheral resident lymphocytes to engage in the regulatory pathway, the MM96 simultaneously explained the maintenance of responsiveness to non-self in a context of suppression mediating dominant self-tolerance. The major difficulty of the MM96 is related to the apparent tissue specificity of Treg repertoires generated intrathymically. This difficulty has now been principally solved by the work of Hanahan, Kyewski and others (Jolicoeur et al. 1994; Derbinski et al. 2001; Anderson et al. 2002; Gotter et al. 2004), demonstrating the selective expression of a variety of tissue-specific antigens by TECs, in topological patterns that are compatible with the MM96, but difficult to conciliate with recessive tolerance models (Kappler et al. 1987; Kisielow et al. 1988). While the developmentally regulated multireactivity of TCR repertoires (Gavin and Bevan 1995), as well as the peripheral recruitment of Treg among RTE (Modigliani et al. 1996a) might add to this process, it would seem that the establishment of tissue-specific tolerance essentially stems from the "promiscuous expression of tissue antigens" by TEC. The findings of AID resulting from natural mutations (reviewed in Pitkanen and Peterson 2003) or the targeted inactivation (Anderson et al. 2002; Ramsey et al. 2002) of the AIRE transcription factor that regulates promiscuous gene expression on TECs support this conclusion. The observations on the correlation of natural or forced expression of the Foxp3 transcription factor in CD4 T cells with Treg phenotype and function (Fontenot et al. 2003; Hori et al. 2003; Khattri et al. 2003) provided support for the MM96 contention that Treg represent a unique differentiative pathway that is naturally established inside the thymus. Furthermore, Caton and colleagues (Jordan et al. 2001), as well as several other groups (Bensinger et al. 2001; Apostolou et al. 2002), have provided direct evidence for our postulate that Treg are selected among differentiating CD4 T cells with high affinity for ligands expressed on TECs (Modigliani et al. 1996b). Finally, the demonstration by Caramalho et al. that Treg express innate immunity receptors (Caramalho et al. 2003) and respond to pro-inflammatory signals and products of inflammation (Caramalho et al., submitted) brought about a new understanding on the peripheral regulation of Treg function. Together with the observation that Treg also respond to ongoing activities of "naïve/effector" T cells--possibly through the IL-2 produced in these conditions--these findings explain the participation of Treg in all immune responses (Onizuka et al. 1999; Shimizu et al. 1999; Annacker et al. 2001; Curotto de Lafaille et al. 2001; Almeida et al. 2002; Shevach 2002; Bach and Francois Bach 2003; Wood and Sakaguchi 2003; Mittrucker and Kaufmann 2004; Sakaguchi 2004), beyond their fundamental role in ensuring self-tolerance (e.g., Modigliani et al. 1996a; Shevach 2000; Hori et al. 2003; Sakaguchi 2004; Thompson and Powrie 2004). Thus, anti-inflammatory and anti-proliferative Treg are amplified by signals that promote or mediate inflammation and proliferation, accounting for the quality control of responses (Coutinho et al. 2001). In turn, such natural regulation of Treg by immune responses to non-self may well explain the alarming epidemiology of allergic and AID in wealthy societies (Wills-Karp et al. 2001; Bach 2002; Yazdanbakhsh et al. 2002), where a variety of childhood infections have become rare or absent. Thus, it is plausible that Treg were evolutionarily set by a given density of infectious agents in the environment. With hindsight, it is not too surprising that natural Treg performance falls once hygiene, vaccination, and antibiotics suddenly (i.e., 100 years) plunged infectious density to below some critical physiological threshold. As the immune system is not adapted to modern clean conditions of postnatal development, clinical immunologists must now deal with frequent Treg deficiencies (allergies and AID) for which they have no curative or rational treatments. It is essential, therefore, that basic immunologists concentrate on strategies to selectively stimulate the production, survival, and activity of this set of lymphocytes that is instrumental in preventing immune pathology. We have argued that the culprit of this inability of basic research to solve major clinical problems has been the self-righteousness of recessive tolerance champions, from Ehrlich to some of our contemporaries. It is ironical, however, that none of us--including the heretic opponents of horror autotoxicus--had understood that self-tolerance, or its robustness at least, is in part determined by the frequency and intensity of the responses to non-self. In the evolution of ideas on immunological tolerance, the time might be ripe for some kinds of synthesis. First, conventional theory reduced self-tolerance to negative selection and microbial defense to positive selection, while the MM96 solution was the precise opposite: positive selection of autoreactivities for self-tolerance (Treg) and negative selection (of Treg) for ridding responses. In contrast, it would now appear that positive and negative selection of autoreactive T cells are both necessary to establish either self-tolerance or competence to eliminate microbes, two processes that actually reinforce each other in the maintenance of self-integrity. Second, V-region recognition has generally been held responsible for specific discrimination between what should be either tolerated or eliminated from the organism. In contrast again, it would now seem that both processes of self-tolerance and microbial defense (self/non-self discrimination) also operate on the basis of evolutionarily ancient, germ-line-encoded innate, nonspecific receptors (Medzhitov and Janeway 2000) capable of a coarse level of self/non-self discrimination (Coutinho 1975). It could thus be interesting to revisit notions of cooperativity between V-regions and such mitogen receptors, both in single cell functions (Coutinho et al. 1974) and in the system's evolution (Coutinho 1975, 1980) as well. After all, major transitions in evolution were cooperative (Maynard-Smith and Szathmary 1995).

Animals↗