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PubMed2005

Awareness, acceptance, and action: an emerging framework for understanding AIDS stigmatizing attitudes among community leaders in Barbados.

AIDS stigma must be acknowledged and reduced to advance HIV prevention and HIV/AIDS care in a variety of settings worldwide, including in the West Indies where national epidemics are thought to be growing rapidly. Regarded by international health organizations as a formidable barrier to service delivery and receipt, AIDS stigma refers to prejudice and discrimination directed toward people living with HIV/AIDS (PLHA), persons perceived as being at risk for HIV infection, and the informal and formal service providers who care for PLHA. However, there is little evidence of successful antistigma interventions in the literature. Furthermore, beyond studies of willingness in various professions to serve clients or patients with HIV/AIDS, the stigmatizing attitudes and behaviors of service delivery personnel, paraprofessionals and volunteers have been inadequately studied. This paper uses data obtained during an AIDS awareness workshop with sports coaches in Barbados to illustrate principles of an antistigma intervention framework being developed for social service and health personnel. The Awareness/Acceptance/Action Model (AAAM) draws on principles of mindfulness, rooted in ancient Asian traditions, and recently adapted to a range of physical and mental health interventions in Western contexts. Mindfulness techniques encourage awareness of one's current state and environment, acceptance of the implications of one's attitudes and behaviors, and the development of intentional responses rather than habitually patterned reactions. In this initial effort, community leaders were guided through a series of self-reflective exercises focusing AAAM principles on their tendencies toward AIDS stigma, and exploring more compassionate and functional alternatives.

Acquired Immunodeficiency Syndrome↗
PubMed2025

The genetic basis of chloride exclusion in grapevines.

Mediterranean regions are among the most important areas for global grape production, characterized by dry climates and frequent challenges associated with soil salinity. In these environments, chloride toxicity is a major factor limiting vine growth and fruit quality. Despite the critical role of chloride exclusion in salinity tolerance, the genetic mechanisms underlying this trait remain poorly understood. In this study, we analyzed natural variation in chloride exclusion using a diverse panel of 335 accessions representing 18 wild and cultivated Vitis species. This panel, comprising accessions from the southwestern United States and Mexico, captures a broad range of evolutionary adaptations to abiotic stress and provides a valuable genetic resource for breeding efforts aimed at introducing novel traits. Using genome-wide association and quantitative trait loci (QTL) mapping, we identified a major QTL on chromosome 8, now designated qClEx8.1, containing candidate genes encoding cation/H⁺ exchangers (CHXs), which are involved in ion transport and homeostasis. To validate these findings, we analyzed a mapping population derived from Vitis acerifolia longii 9018 and the commercial rootstock GRN3, confirming the chromosome 8 locus as a major determinant of chloride exclusion. Structural variant analysis revealed nonsynonymous substitutions within CHX genes that may influence protein function and salinity tolerance. Additionally, we discovered a novel QTL on chromosome 19 enriched with G-type lectin S-receptor-like serine/threonine-protein kinases, known regulators of stress signaling. By integrating phenotypic and genomic data across a diverse Vitis collection, this study advances our understanding of the genetic architecture underlying chloride exclusion and highlights candidate genes for breeding salt-tolerant rootstocks.

Vitis↗
PubMed1994

Hemophilia growth and development study: baseline neurodevelopmental findings.

Reported baseline findings from the neurological assessment component of the Hemophilia Growth and Development Study (HGDS). HIV-positive (HIV+; n = 207) and HIV-negative (HIV-; n = 126) young males with hemophilia ages 6 to 18 years, were enrolled in a prospective study of their growth and development. At baseline, HIV+ and HIV- subjects were not significantly different in test performance. The number of subjects exhibiting below-average performance in three or more areas assessed was about 25% overall. For both groups, mean test scores were within the average range. Academic and adaptive skills were lower than expected based on mean IQ scores, and more behavioral/emotional problems than expected were reported by parents. Absolute CD4 cell counts per mm3 were not related to neuropsychological performance at baseline. Results suggest that the subjects with HIV were relatively free of HIV-related neuropsychological impairment at baseline and that observed differences from a general population reflect effects of hemophilia as a chronic illness.

Adolescent↗
PubMed2005

Cecal ligation and puncture.

The model of cecal ligation and puncture (CLP) in rodents has been used extensively to investigate the clinical settings of sepsis and septic shock. This model produces a hyperdynamic, hypermetabolic state that can lead to a hypodynamic, hypometabolic stage, and eventual death. Blood cultures are positive for enteric organisms very early after CLP. The model has been widely used over the past 26 years and is highly versatile in adapting to a range of severity and testing objectives. It is inexpensive to prepare and technically straightforward. Aspects of sepsis research investigated using CLP include energetics, metabolism, resuscitation, antibiotic therapy, microbial factors, cardiovascular responses, immune function, mediator release, and cytokine expression patterns. The challenge of the small circulating blood volume in rodents can be overcome by using micromethods that enable analysis of small volumes, or alternatively, by using a large number of animals to obtain serial samples.

Animals↗
PubMed2004

Advanced detection systems for X-ray fluorescence excitation spectroscopy.

This paper accounts for selected detector developments carried out over the past 15 years within the ESRF X-ray Absorption Spectroscopy group. This includes various types of photodiodes used as integrated current detectors. Special emphasis is put on the long-standing development of a Si drift-diode array suitable for energy-dispersive detection of X-ray fluorescence. This detector, which is now operational, was used to record high-quality XMCD/XAFS spectra on [Fe70Pt30] nanoparticles highly dispersed on a Si wafer. Using numerically deconvoluted spectra, energy resolution was decreased to 82 eV for the Si Kalphabeta line, 126 eV for the Fe Kalpha line and 176 eV for the Pt Lalpha line. A high-vacuum-compatible high-energy-resolution crystal analyzer was also installed on ID12, making it possible to record X-ray fluorescence excitation spectra in the photon-in/photon-out mode over a wide spectral range. Prospects of adapting these methods in order to investigate biological samples are briefly discussed.

Equipment Design↗
PubMed1987

Adaptation of dental amalgam to the cavosurface margin of Class I cavity preparations.

The adaptation of a range of amalgam alloys to the cavosurface margin of Class I cavity preparations was examined for two condensation techniques. The marginal contour of amalgam condensed into the cavity preparation and packed approximately 1 mm past the cavosurface margin was compared with amalgam margins of restorations which were packed to final contour with minimal carving. The effect of burnishing and/or polishing the cavosurface margin was compared with carving the amalgam to the cavosurface margin. Specimens were sectioned, metallographically polished and examined using a light microscope. The technique of overpacking amalgam produced a greater number of acceptable amalgam margins at the cavosurface margin than the condensation technique of packing to final contour, the best cavosurface margin was produced when specimens were burnished and polished, the carved margin being the least desirable. The cuspal incline also influenced the quality of the marginal finish with the difficulty of marginal finishing increasing with the steepness in cuspal incline.

Dental Alloys↗
PubMed2005

Chloroplast and microsatellite DNA diversities reveal the introduction history of Brazilian peppertree (Schinus terebinthifolius) in Florida.

Brazilian peppertree (Schinus terebinthifolius) is a woody perennial that has invaded much of Florida. This native of northeastern Argentina, Paraguay, and Brazil was brought as an ornamental to both the west and east coasts of Florida at the end of the 19th century. It was recorded as an invader of natural areas in the 1950s, and has since extended its range to cover over 280 000 ha. Our goals were to understand the history of this invasion, as one step toward understanding why this exotic was so successful, and ultimately to improve development of biological control agents. We sampled plants from the native and exotic ranges, particularly Florida, and genotyped these individuals at nuclear and chloroplast loci. Nuclear microsatellite and cpDNA loci reveal strong genetic population structure consistent with limited dispersal in the introduced and native ranges. Bayesian clustering of microsatellite data separates the east and west coast plants in Florida into distinct populations. The two chloroplast haplotypes found in Florida are also concordant with this separation: one predominates on the east coast, the other on the west coast. Analysis of samples collected in South America shows that haplotypes as distinct as the two in Florida are unlikely to have come from a single source population. We conclude that the genetic evidence supports two introductions of Brazilian peppertree into Florida and extensive hybridization between them. The west coast genotype likely came from coastal Brazil at about 27 degrees south, whereas the east coast genotype probably originated from another, as yet unidentified site. As a result of hybridization, the Florida population does not exhibit low genetic variation compared to populations in the native range, possibly increasing its ability to adapt to novel environments. Hybridization also has important consequences for the selection of biocontrol agents since it will not be possible to identify closely co-adapted natural enemies in the native range, necessitating more extensive host testing.

Anacardiaceae↗
PubMed2005

Identification of novel heat shock factor-dependent genes and biochemical pathways in Arabidopsis thaliana.

In order to assess specific functional roles of plant heat shock transcription factors (HSF) we conducted a transcriptome analysis of Arabidopsis thaliana hsfA1a/hsfA1b double knock out mutants and wild-type plants. We used Affymetrix ATH1 microarrays (representing more than 24 000 genes) and conducted hybridizations for heat-treated or non-heat-treated leaf material of the respective lines. Heat stress had a severe impact on the transcriptome of mutant and wild-type plants. Approximately 11% of all monitored genes of the wild type showed a significant effect upon heat stress treatment. The difference in heat stress-induced gene expression between mutant and wild type revealed a number of HsfA1a/1b-regulated genes. Besides several heat shock protein and other stress-related genes, we found HSFA-1a/1b-regulated genes for other functions including protein biosynthesis and processing, signalling, metabolism and transport. By screening the profiling data for genes in biochemical pathways in which known HSF targets were involved, we discovered that at each step in the pathway leading to osmolytes, the expression of genes is regulated by heat stress and in several cases by HSF. Our results document that in the immediate early phase of the heat shock response HSF-dependent gene expression is not limited to known stress genes, which are involved in protection from proteotoxic effects. HsfA1a and HsfA1b-regulated gene expression also affects other pathways and mechanisms dealing with a broader range of physiological adaptations to stress.

Arabidopsis↗
PubMed2006

Changes in the community structure and activity of betaproteobacterial ammonia-oxidizing sediment bacteria along a freshwater-marine gradient.

To determine whether the distribution of estuarine ammonia-oxidizing bacteria (AOB) was influenced by salinity, the community structure of betaproteobacterial ammonia oxidizers (AOB) was characterized along a salinity gradient in sediments of the Ythan estuary, on the east coast of Scotland, UK, by denaturant gradient gel electrophoresis (DGGE), cloning and sequencing of 16S rRNA gene fragments. Ammonia-oxidizing bacteria communities at sampling sites with strongest marine influence were dominated by Nitrosospira cluster 1-like sequences and those with strongest freshwater influence were dominated by Nitrosomonas oligotropha-like sequences. Nitrosomonas sp. Nm143 was the prevailing sequence type in communities at intermediate brackish sites. Diversity indices of AOB communities were similar at marine- and freshwater-influenced sites and did not indicate lower species diversity at intermediate brackish sites. The presence of sequences highly similar to the halophilic Nitrosomonas marina and the freshwater strain Nitrosomonas oligotropha at identical sampling sites indicates that AOB communities in the estuary are adapted to a range of salinities, while individual strains may be active at different salinities. Ammonia-oxidizing bacteria communities that were dominated by Nitrosospira cluster 1 sequence types, for which no cultured representative exists, were subjected to stable isotope probing (SIP) with 13C-HCO3-, to label the nucleic acids of active autotrophic nitrifiers. Analysis of 13C-associated 16S rRNA gene fragments, following CsCl density centrifugation, by cloning and DGGE indicated sequences highly similar to the AOB Nitrosomonas sp. Nm143 and Nitrosomonas cryotolerans and to the nitrite oxidizer Nitrospira marina. No sequence with similarity to the Nitrosospira cluster 1 clade was recovered during SIP analysis. The potential role of Nitrosospira cluster 1 in autotrophic ammonia oxidation therefore remains uncertain.

Ammonia↗
PubMed1978

Evaluation of goal attainment in geriatric settings.

Determination of the impact of programs designed to enhance the functional independence of geriatric residents requires prior specification of goals in terms that clearly indicate the desired outcomes. The Geriatric Resident Goals Scale (GRGS) is a listing of specific goals developed to provide a systematic means of assessing resident status and program effectiveness. For male residents in a VA Nursing Home Care Unit, the obtained internal consistency reliability coefficient was .97 (N = 198), and the reliability coefficient reflecting a combination of test-retest and interrater consistency was .95 (N = 22). For a group of 178 residents, the GRGS was predictive of level of independence ratings (r = .82) and mental status (r = .71). The data showed the GRGS to be a highly reliable and valid means of assessing the functioning of geriatric residents, lending support to an assessment process based on a listing of specific goals. The GRGS can be viewed as a general procedure that is adaptable to a range of geriatic settings and programs.

Activities of Daily Living↗
PubMed1993

Aortic pressure estimation with electro-mechanical circulatory assist devices.

An adaptive technique for the estimation of the time history of aortic pressure (from applied voltage and position feedback) has been designed, implemented, and bench tested using the Penn State Electric Ventricular Assist Device (EVAD). This method, known in the field of automatic control as a dynamic observer, utilizes gains which were determined using experimental data collected while the EVAD was running on a mock circulatory system. An adaptive scheme provides the observer with a method of changing its initial conditions on a stroke-by-stroke basis which improves observer performance. In both determining the feedback gains and developing the adaptation scheme, a range of beat rates and pressure loads was taken into account to yield satisfactory observer performance over a range of operating conditions. The observer was implemented, its performance was verified in vitro and results are reported. In the six experimental operating conditions, the beat rate ranged from 56-104 beats per minute (bpm) and the span of the mean systolic aortic pressure was 10.7-18.7 kPa (80-140 mmHg). For these cases, the mean deviation between the actual and estimated aortic pressure during the latter two-thirds of systole was 0.41 kPa (3.1 mmHg).

Algorithms↗
PubMed2001

Temperature-regulated protein synthesis by Leptospira interrogans.

Leptospira interrogans is an important mammalian pathogen. Transmission from an environmental source requires adaptations to a range of new environmental conditions in the organs and tissues of the infected host. Since many pathogenic bacteria utilize temperature to discern their environment and regulate the synthesis of appropriate proteins, we investigated the effects of temperature on protein synthesis in L. interrogans. Bacteria were grown for several days after culture temperatures were shifted from 30 to 37 degrees C. Triton X-114 cellular fractionation identified several proteins of the cytoplasm, periplasm, and outer membrane for which synthesis was dependent on the culture temperature. Synthesis of a cytoplasmic protein of 20 kDa was switched off at 37 degrees C, whereas synthesis of a 66-kDa periplasmic protein was increased at the higher temperature. Increased synthesis of a 25-kDa outer membrane protein was observed when the organisms were shifted from 30 to 37 degrees C. A 36-kDa protein synthesized at 30 but not at 37 degrees C was identified as LipL36, an outer membrane lipoprotein. In contrast, expression of another lipoprotein, LipL41, was the same at either temperature. Immunoblotting with convalescent equine sera revealed that some proteins exhibiting thermoregulation of synthesis elicited antibody responses during infection. Our results show that sera from horses which aborted as a result of naturally acquired infection with L. interrogans serovar pomona type kennewicki recognize periplasmic and outer membrane proteins which are differentially synthesized in response to temperature and which therefore may be important in the host-pathogen interaction during infection.

Antigens, Bacterial↗
PubMed2001

Molecular characterization of thermoinduced immunogenic proteins Q1p42 and Hsp15 of Leptospira interrogans.

Leptospira interrogans is a mammalian pathogen which must adapt to a range of new environmental conditions including temperature change when it infects new hosts. In vitro studies of organisms cultured at 30 degrees C and shifted to 37 degrees C for 5 to 7 days have confirmed that synthesis of several proteins involved in equine infection is regulated in response to temperature change (J. E. Nally, J. F. Timoney, and B. Stevenson, Infect. Immun. 69:400-404, 2001). In order to specifically identify antigenic proteins upregulated at 37 degrees C, groups of three ponies were immunized with organisms shifted to 37 degrees C for 5 to 7 days or with organisms maintained at 30 degrees C. A lambda ZAP II genomic DNA library was screened with the pool of antisera to organisms shifted to 37 degrees C. Clones reactive with this pool but unreactive with the pool of pony antisera to organisms cultured at 30 degrees C were selected for further analysis. Sequence analysis of the first two clones identified open reading frames for proteins designated Qlp42 and Hsp15. Qlp42 is predicted to be an outer membrane lipoprotein. Its synthesis was upregulated when cultures were shifted from 30 to 37 degrees C and downregulated when cultures were shifted from 37 to 30 degrees C. Although the predicted molecular mass of Qlp42 is 39.8 kDa for the mature protein, Qlp42-specific equine antiserum was reactive with two bands of 30 and 29.5 kDa. Hsp15 is a stress response protein and a member of the Hsp20/alpha-crystallin family. PCR detected homologues of qlp42 and hsp15 in pathogenic serovars of L. interrogans but not in the nonpathogenic Leptospira biflexa. Enzyme-linked immunosorbent assays of antibody in convalescent sera from mares naturally infected with L. interrogans suggest that Qlp42 is expressed during leptospiral infection.

Amino Acid Sequence↗
PubMed2006

Involvement of Bacillus subtilis ClpE in CtsR degradation and protein quality control.

The heat-inducible CtsR regulon of Bacillus subtilis codes for three Clp proteins with chaperone or protease activity. While the importance of ClpC and ClpP has been elucidated for a wide range of cellular adaptation processes, this study deals with the physiological role of B. subtilis ClpE. Northern experiments and reporter gene analyses revealed that ClpE is essential both for efficient CtsR-dependent gene derepression and for rerepression during heat stress. ClpEP was found to destabilize the global regulator CtsR after heat shock in vivo with different kinetics than ClpCP, which is known to degrade CtsR in vitro and in vivo upon heat stress. Furthermore, ClpE was localized at heat-generated inclusion bodies by electron microscopy. The comparison of radiolabeled aggregated protein fractions of wild-type and clpE mutant cells during heat stress displayed a significant delay of protein disaggregation in the absence of ClpE. A kinetic Western blotting approach confirmed the long-term residence of ClpE in the insoluble cell fraction rather than in the cytoplasmic fraction. These observations indicate the involvement of ClpE in global protein disaggregation. As a characteristic structural element of ClpE, the N-terminal zinc finger domain was proven to be essential for basal in vitro ATPase activity.

Adenosine Triphosphatases↗
PubMed1973

Continuous culture of Rhodotorula rubra: kinetics of phosphate-arsenate uptake, inhibition, and phosphate-limited growth.

The pink yeast Rhodotorula rubra of marine origin was found to be capable of extended growth at very low phosphate concentrations (K(0.5) = 10.8 nm). Average intracellular phosphate concentrations, based on isotope exchange techniques, were 15 to 200 nm, giving concentration gradients across the cell envelope of about 10(6). Sensitivity to metabolic inhibitors occurred at micromolar concentrations. Inability of the phosphate transport system, K(s) = 0.5 to 2.8 mum, V(max) = 55 mumoles per g of cells per min, to discriminate against arsenate transport led to arsenate toxicity at 1 to 10 nm, whereas environmental arsenate levels are reportedly much higher. Phosphate competitively prevented arsenate toxicity. The K(i) for phosphate inhibition of arsenate uptake was 0.7 to 1.2 mum. Phosphate uptake experiments showed that maximal growth rates could be achieved with approximately 4% of the total phosphate-arsenate transport system. Organisms adapted to a range both of concentration of NaCl and of pH. Maximal affinity for phosphate occurred at pH 4 and at low concentrations of NaCl; however, V(max) for phosphate transport was little affected. Maximal specific growth rates on minimal medium were consistent in batch culture but gradually increased to the much higher rates found with yeast extract media when the population was subjected to long-term continuous culture with gradually increasing dilution rates. Phosphate initial uptake rates that were in agreement with the steady-state flux in continuous culture were obtained by using organisms and medium directly from continuous culture. This procedure resulted in rates about 500 times greater than one in which harvested batch-grown cells were used. Discrepancies between values found and those reported in the literature for other organisms were even larger. Growth could not be sustained below a threshold phosphate concentration of 3.4 nm. Such thresholds are explained in terms of a system where growth rate is set by intracellular nutrient concentrations. Threshold concentrations occur in response to nutrient sinks not related to growth, such as efflux and endogenous metabolism. Equations are presented for evaluation of growth rate-limiting substrate concentrations in the presence of background substrate and for evaluating low inhibitor concentration inhibition mechanisms by substrate prevention of inhibitor flux.

Arsenic↗
PubMed2001

Genetic diversity in RNA virus quasispecies is controlled by host-virus interactions.

Many RNA viruses have genetically diverse populations known as quasispecies. Important biological characteristics may be related to the levels of diversity in the quasispecies (quasispecies cloud size), including adaptability and host range. Previous work using Tobacco mosaic virus and Cucumber mosaic virus indicated that evolutionarily related viruses have very different levels of diversity in a common host. The quasispecies cloud size for these viruses remained constant throughout serial passages. Inoculation of these viruses on a number of hosts demonstrated that quasispecies cloud size is not constant for these viruses but appears to be dependent on the host. The quasispecies cloud size remained constant as long as the viruses were maintained on a given host. Shifting the virus between hosts resulted in a change in cloud size to levels associated with the new host. Quasispecies cloud size for these viruses is related to host-virus interactions, and understanding these interactions may facilitate the prediction and prevention of emerging viral diseases.

Genetic Variation↗
PubMed2001

Transcription factor HIF-1 is a necessary mediator of the pasteur effect in mammalian cells.

The ability to respond to differential levels of oxygen is important to all respiring cells. The response to oxygen deficiency, or hypoxia, takes many forms and ranges from systemic adaptations to those that are cell autonomous. Perhaps the most ancient of the cell-autonomous adaptations to hypoxia is a metabolic one: the Pasteur effect, which includes decreased oxidative phosphorylation and an increase in anaerobic fermentation. Because anaerobic fermentation produces far less ATP than oxidative phosphorylation per molecule of glucose, increased activity of the glycolytic pathway is necessary to maintain free ATP levels in the hypoxic cell. Here, we present genetic and biochemical evidence that, in mammalian cells, this metabolic switch is regulated by the transcription factor HIF-1. As a result, cells lacking HIF-1alpha exhibit decreased growth rates during hypoxia, as well as decreased levels of lactic acid production and decreased acidosis. We show that this decrease in glycolytic capacity results in dramatically lowered free ATP levels in HIF-1alpha-deficient hypoxic cells. Thus, HIF-1 activation is an essential control element of the metabolic state during hypoxia; this requirement has important implications for the regulation of cell growth during development, angiogenesis, and vascular injury.

Adaptation, Physiological↗
PubMed2006

An official ATS statement: hepatotoxicity of antituberculosis therapy.

Drug-induced liver injury (DILI) is a problem of increasing significance, but has been a long-standing concern in the treatment of tuberculosis (TB) infection. The liver has a central role in drug metabolism and detoxification, and is consequently vulnerable to injury. The pathogenesis and types of DILI are presented, ranging from hepatic adaptation to hepatocellular injury. Knowledge of the metabolism of anti-TB medications and of the mechanisms of TB DILI is incomplete. Understanding of TB DILI has been hampered by differences in study populations, definitions of hepatotoxicity, and monitoring and reporting practices. Available data regarding the incidence and severity of TB DILI overall, in selected demographic groups, and in those coinfected with HIV or hepatitis B or C virus are presented. Systematic steps for prevention and management of TB DILI are recommended. These include patient and regimen selection to optimize benefits over risks, effective staff and patient education, ready access to care for patients, good communication among providers, and judicious use of clinical and biochemical monitoring. During treatment of latent TB infection (LTBI) alanine aminotransferase (ALT) monitoring is recommended for those who chronically consume alcohol, take concomitant hepatotoxic drugs, have viral hepatitis or other preexisting liver disease or abnormal baseline ALT, have experienced prior isoniazid hepatitis, are pregnant or are within 3 months postpartum. During treatment of TB disease, in addition to these individuals, patients with HIV infection should have ALT monitoring. Some experts recommend biochemical monitoring for those older than 35 years. Treatment should be interrupted and, generally, a modified or alternative regimen used for those with ALT elevation more than three times the upper limit of normal (ULN) in the presence of hepatitis symptoms and/or jaundice, or five times the ULN in the absence of symptoms. Priorities for future studies to develop safer treatments for LTBI and for TB disease are presented.

Antitubercular Agents↗