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Autoradiographs have been prepared from frog toe muscles soaked in Ca(45) and fixed with an osmium-oxalate solution. A majority of the grains over the A bands were over the myofibrils. The grain density over the I bands was greatest over the space between the myofibrils. The significance of this distribution is discussed in the light of previous information about the longitudinal distribution of Ca(45) in skeletal muscle.
Risk assessment of exposure to sources of radiation is an important tool for national governments in regulating radionuclide emissions and thus reducing radiation doses for the general public. For this reason radiation doses from sources throughout The Netherlands have been analyzed. For sources with well-defined locations and doses that were thought to vary significantly throughout The Netherlands, radiation dose maps were produced. Average dose values were calculated or derived from the literature for doses considered to be evenly distributed throughout the country or for which no information on the geographical distribution of dose was available. Emission, dispersion, and individual dose were modeled for each source using various pathways and exposure routes. Indoor radon and gamma radiation from building materials generate the highest dose values. The highest human induced radiation doses for industries of which the doses showed to be geographically distributed are found in the cement industry, elemental phosphorus production, phosphoric acid production, and iron and steel production. Radiation dose from some of these sources has a very local peak and decreases rapidly with distance. The elemental phosphorus production causes relatively high radiation doses throughout a large part of The Netherlands. Cumulation of doses from various sources occurs, but these are often masked by doses from a few large industries.
The equilibrium, kinetics, diffusion and self-association of proteins at membrane/solution interfaces may deviate substantially from these processes in bulk solution. A set of methods for examining these phenomena combines substrate-supported planar model membranes and the use of evanescent illumination with laser-based, quantitative fluorescence microscopy. Measurement of the steady-state, surface-associated fluorescence can be used to examine the thermodynamic properties of proteins at membranes. When combined with fluorescence photobleaching recovery, this technique provides information about membrane-binding kinetics; and when combined with fluorescence pattern photobleaching recovery, measurement of the translational diffusion coefficients of proteins weakly bound to membranes is possible. The use of polarized evanescent illumination can provide information about the orientation distributions of adsorbed fluorophores. Fluorescence correlation spectroscopy provides information about the self-association (e.g. dimerization) of membrane-associated proteins.
Organisms belonging to the OP11 candidate phylogenetic division of Bacteria have been detected only in rRNA-based sequence surveys of environmental samples. Preliminary studies indicated that such organisms represented by the sequences are abundant and widespread in nature and highly diverse phylogenetically. In order to document more thoroughly the phylogenetic breadth and environmental distribution of this diverse group of organisms, we conducted further molecular analyses on environmental DNAs. Using PCR techniques and primers directed toward each of the five described subdivisions of OP11, we surveyed 17 environmental DNAs and analyzed rRNA gene sequences in 27 clonal libraries from 14 environments. Ninety-nine new and unique sequences were determined completely, and approximately 200 additional clones were subjected to partial sequencing. Extensive phylogenetic comparisons of the new sequences to those representing other bacterial divisions further resolved the phylogeny of the bacterial candidate division OP11 and identified two new candidate bacterial divisions, OP11-derived 1 (OD1) and Sulphur River 1 (SR1). The widespread environmental distribution of representatives of the bacterial divisions OD1, OP11, and SR1 suggests potentially conspicuous biogeochemical roles for these organisms in their respective environments. The information on environmental distribution offers clues for attempts to culture landmark representatives of these novel bacterial divisions, and the sequences are specific molecular signatures that provide for their identification in other contexts.
Single-photon emission computed tomography (SPECT) provides three-dimensional (3D) image information about the distribution of a radiopharmaceutical injected into the patient for diagnostic purposes. By combining conventional scintigraphic and computed tomographic methods, SPECT images present 3D functional information about the patient in more detail and higher contrast than found in planar scintigrams. A typical SPECT system consists of one or more scintillation cameras that acquire multiple two-dimensional planar projection images around the patient. The projection data are reconstructed into 3D images. The collimator of the scintillation camera has substantial effects on the spatial resolution and detection efficiency of the SPECT system. Physical factors such as photon attenuation and scatter affect the quantitative accuracy and quality of SPECT images, and various methods have been developed to compensate for these image-degrading effects. In myocardial SPECT, an important application of SPECT, recent use of attenuation compensation methods has provided images with reduced artifacts and distortions caused by the non-uniform attenuation in the chest region and by the diaphragmatic and breast attenuation. Attenuation-compensated myocardial SPECT images have the potential to improve clinical diagnosis by reducing the false-positive and false-negative detection of myocardial defects. In the future, further improvement in SPECT images will be realized from the continuous development of new radio-pharmaceuticals for new clinical applications, instrumentation with high spatial resolution and detection efficiency, and image reconstruction algorithms and compensation methods that reduce the image-degrading effects of the collimator-detector, attenuation, and scatter.
It is not known whether psychophysical performance depends primarily on small numbers of neurons optimally tuned to specific visual stimuli, or on larger populations of neurons that vary widely in their properties. Tuning bandwidths of single cells can provide important insight into this issue, yet most bandwidth measurements have been made using suprathreshold visual stimuli, whereas psychophysical measurements are frequently obtained near threshold. We therefore examined the directional tuning of cells in the middle temporal area (MT, or V5) using perithreshold, stochastic motion stimuli that we have employed extensively in combined psychophysical and physiological studies. The strength of the motion signal (coherence) in these displays can be varied independently of its direction. For each MT neuron, we characterized the directional bandwidth by fitting Gaussian functions to directional tuning data obtained at each of several motion coherences. Directional bandwidth increased modestly as the coherence of the stimulus was reduced. We then assessed the ability of MT neurons to discriminate opposed directions of motion along six equally spaced axes of motion spanning 180 degrees. A signal detection analysis yielded neurometric functions for each axis of motion, from which neural thresholds could be extracted. Neural thresholds remained surprisingly low as the axis of motion diverged from the neuron's preferred-null axis, forming a plateau of high to medium sensitivity that extended approximately 45 degrees on either side of the preferred-null axis. We conclude that directional tuning remains broad in MT when motion signals are reduced to near-threshold values. Thus directional information is widely distributed in MT, even near the limits of psychophysical performance. These observations support models in which relatively large numbers of signals are pooled to inform psychophysical decisions.
The authors begin by presenting a brief historical summary of hospital pharmacists' activities in Portugal, especially since the 1950s. They state their views on the present situation of hospital pharmacy in various aspects, namely: general legislation; activities and premises of pharmacy services; pharmaceutical career and staff recruitment; the National Hospital Formulary of Medicines and Pharmacy and Therapeutic Committees; acquisition, production and distribution of medicines; and clinical pharmacy activities. Future trends of hospital pharmacy in Portugal are summarized, stressing the following points: evolution of production and information, unit dose distribution, and steady increase of other clinical pharmacy activities.
BACKGROUND: Fluctuating asymmetry is assumed to measure individual and population level developmental stability. The latter may in turn show an association with stress, which can be observed through asymmetry-stress correlations. However, the recent literature does not support an ubiquitous relationship. Very little is known why some studies show relatively strong associations while others completely fail to find such a correlation. We propose a new Bayesian statistical framework to examine these associations RESULTS: We are considering developmental stability - i.e. the individual buffering capacity - as the biologically relevant trait and show that (i) little variation in developmental stability can explain observed variation in fluctuating asymmetry when the distribution of developmental stability is highly skewed, and (ii) that a previously developed tool (i.e. the hypothetical repeatability of fluctuating asymmetry) contains only limited information about variation in developmental stability, which stands in sharp contrast to the earlier established close association between the repeatability and developmental instability. CONCLUSION: We provide tools to generate valuable information about the distribution of between-individual variation in developmental stability. A simple linear transformation of a previous model lead to completely different conclusions. Thus, theoretical modelling of asymmetry and stability appears to be very sensitive to the scale of inference. More research is urgently needed to get better insights in the developmental mechanisms of noise and stability. In spite of the fact that the model is likely to represent an oversimplification of reality, the accumulation of new insights could be incorporated in the Bayesian statistical approach to obtain more reliable estimation.
OBJECTIVE: Identify a source of contamination to explain the increase in the number of cases of S. Paratyphi B var. Java infection. METHOD: A descriptive study was conducted to gather more information about cases and potential risk factors for infection. Between January 2000 and June 2003, we identified and interviewed by questionnaire 53 people with S. Paratyphi B infection. Due to the suspected link with fish tanks, an environmental investigation was conducted for each case at patients' homes as well as at pet stores and wholesalers. Various samples were taken from fish tanks. The fish were purchased at different pet shops. The pulsed field gel electrophoresis method was used to compare the human and aquarium strains. RESULTS: Of those infected, 60% had bought or had contact with an aquarium or tropical fishes before becoming ill. More than 50% of the samples taken from fish tanks in homes, pet shops, and wholesaler operations contained a number of serotypes of Salmonella in addition to Salmonella Paratyphi B var. Java. There were similarities between the PFGE patterns of human strains and aquarium samples. DISCUSSION: Contact with fish tanks could be a risk factor for developing a Salmonella infection and the public may be unaware of this risk. It was recommended that information be produced and distributed to pet shops and their customers to inform them of safety precautions in order to reduce the risk of contamination from bacterial pathogens that may be present in aquarium water.
The human immunodeficiency virus (HIV) is estimated to have infected more than a million people in the United States and millions more in other countries. Even though there is no vaccine or effective treatment, HIV infection can be prevented through behavioral change. As the lead Public Health Service Agency for disease prevention, the Centers for Disease Control (CDC) has designed and implemented information and education activities with the ultimate goal of preventing HIV infection and AIDS in the United States. The target populations include the general public, school- and college-aged populations, persons infected or at increased risk of infection, minorities, and health workers. Because AIDS will be with us for a long time, CDC views educating the public as a long-term undertaking. The agency has initiated an intensive continuing national public information campaign, an informational brochure to be distributed to every U.S. household, a national AIDS information toll-free hotline, and a clearinghouse system that will maintain a comprehensive inventory of AIDS information resources and services. CDC also supports public information and education efforts by State and local health agencies. To reach school- and college-age youth, CDC, in consultation with governmental and national private sector organizations, developed guidelines for effective school health education to assist school health personnel in determining the scope and content of AIDS education. CDC also works with State and local education agencies to help carry out and evaluate educational efforts to prevent the spread of HIV among school- and college-age youth. The populations with the highest priority for AIDS information and education efforts are those who are at increased risk of acquiring or transmitting the AIDS virus because they use illicit intravenous drugs and share needles, engage in anal intercourse, have many sexual partners, practice prostitution, or engage in sex with those who practice these behaviors. Another high-priority population, because they can infect their offspring,is reproductive age women engaging in high-risk behavior and women infected with HIV who become pregnant. CDC programs targeted to these groups include community health education and risk reduction interventions, counseling and testing for HIV infection, AIDS community demonstration projects, perinatal AIDS prevention projects,and programs focused on preventing AIDS in minority populations. CDC is developing a variety of educational approaches for health workers in clinical settings because they are an important channel for providing accurate AIDS information, helping to assess risk, and counseling to actively reduce risk for the patient, sex partners of the patient, friends, and family members of the patient. CDC has conducted research and provided information and training on the use of HIV laboratory tests. CDC has also developed numerous scientific and technical guidelines and recommendations in consultation with practitioners, public health officials, and others and disseminated these through the Morbidity and Mortality Weekly Report. In addition,CDC has provided information about the risk of HIV transmission in the workplace and about methods of prevention. CDC will continue to evaluate these activities and support research in education and related interventions that may be necessary to prevent infection by the HIV virus. By providing educational support for behavior changes that decrease HIV transmission, we can contribute to AIDS prevention in the 1990s.
OBJECTIVE: To analyze the spatial distribution of highly pathogenic avian influenza (HPAI) and to explore environmental factors associated with HPAI using geographic information system (GIS) techniques in Mainland China. METHODS: Databases were set up using the information of HPAI during epidemics in 2004, and linked to digital maps at provincial and county administrative layers in the country through the ArcGIS 8.3 software. Spatial cluster analyses, spatial statistics analyses and tracking analyses on epidemic situation of HPAI were implemented. Environmental factors associated with HPAI were also analyzed on data related to weather, vegetation and migratory birds etc. RESULTS: Findings from spatial cluster analyses showed that high incidence area was centralized in 113.261 degrees ordm; east longitude and 23. 119 degrees ordm; north latitude with a radius of 1090.52 kilometers (relative risk= 2.646, P value= 0.001). Spatial statistical analyses showed that HPAI took place mainly in capital cities of provinces and surrounding areas as well as in the circumference areas of arterial rivers, lakes and seacoasts. Results also showed that HPAI occurrences were associated with low air temperature, high relative humidity and high air pressure as well as with east & central migration routes of migratory birds. The average normalized difference vegetation index was 0.36 +/- 0.11 in epidemic areas of HPAI. CONCLUSION: HPAI was unrandomly distributed and geographically clustered in China.
The aim of the present study was to obtain information about the distribution of various adhesion molecules within and on the surface of HeLa cells, platelets and endothelial cells in an in vitro model mimicking the early phase of metastasis. Suspensions of HeLa cells and human platelets, added to a medium of cultured human umbilical-vein endothelial cells, were stimulated by the addition of thrombin. Hirudin was added before thrombin in some experiments, and in other experiments the endothelium was pretreated with 0.5 mM acetylsalicylic acid (ASA). The distribution of platelet-endothelial cell adhesion molecule (PECAM), P-selectin, von Willebrand factor (vWf), fibrinogen (FG) and thrombospondin (TSP) was investigated on fixed material from the three experimental settings by using an immunogold electron-microscopic technique on frozen thin sections. Cells that had not been exposed to thrombin or any other type of stimulation were used as controls. PECAM was the only adhesion molecule detected on HeLa cells. It outlined the membrane on tumour cells that were not adherent to platelets in both basic and hirudin experiments. However, tumour cells in close proximity to activated platelets were unlabelled. In contrast, PECAM was detected on both platelets and endothelium in all experimental settings and in controls. P-selectin was only demonstrable on platelets in basic experiments. vWf was found both in endothelium and in platelets in controls and in all experimental settings. FG and TSP were found on platelets only, in a manner similar to that seen with vWf. Thus, among the adhesive factors examined in our experimental model, PECAM is the only one demonstrated on HeLa cells. This suggests that PECAM on tumour cells may play a role as adhesion molecule in the early stage of metastasis. P-selectin, vWf, FG and TSP were also consistently expressed. Therefore, these factors may contribute to the adhesive reactions involved in early metastasis.
This paper describes an independent evaluation of a peer-led STD/HIV prevention intervention conducted by Gay Men Fighting AIDS (GMFA) in a public sex environment (PSE). A variety of quantitative and qualitative research methods were employed to collect data on the intervention process as well as its outcomes. The main aim of the intervention was the distribution of condoms and safer sex literature to PSE users. During a five-month period, over 100,000 condoms and 2,200 safer sex information packs were distributed by GMFA volunteers to the PSE users. Condom provision was identified as the most needed health promotion activity in PSEs in a survey of gay and bisexual men (n = 688) conducted by the evaluators. Data collected showed that condoms provided by GMFA, as well as from other sources, were being used in the PSE. The peer-led focus of the intervention was acceptable to the PSE users. In addition, high levels of commitment and input from the volunteers contributed considerable added value to the intervention. The evaluation found that GMFA was successful in reaching the target population and addressing their needs and demands.
The Sabiston Textbook of Surgery and other classic textbooks have been invaluable resources for generations of surgeons. Although they play an important role in medical education, printed textbooks often cannot meet the daily information needs of practicing surgeons because they are inaccessible, incomplete, unstructured, and out of date. Advances in communication technology have radically changed the creation and distribution of medical information. Many clinicians now seek evidence to support clinical decisions on the Internet and handheld devices. This article describes the evolution of surgical textbooks from printed volumes to versatile collections of knowledge that serve as both comprehensive resources and question-answering tools.
BACKGROUND: Most genes in Arabidopsis thaliana are members of gene families. How do the members of gene families arise, and how are gene family copy numbers maintained? Some gene families may evolve primarily through tandem duplication and high rates of birth and death in clusters, and others through infrequent polyploidy or large-scale segmental duplications and subsequent losses. RESULTS: Our approach to understanding the mechanisms of gene family evolution was to construct phylogenies for 50 large gene families in Arabidopsis thaliana, identify large internal segmental duplications in Arabidopsis, map gene duplications onto the segmental duplications, and use this information to identify which nodes in each phylogeny arose due to segmental or tandem duplication. Examples of six gene families exemplifying characteristic modes are described. Distributions of gene family sizes and patterns of duplication by genomic distance are also described in order to characterize patterns of local duplication and copy number for large gene families. Both gene family size and duplication by distance closely follow power-law distributions. CONCLUSIONS: Combining information about genomic segmental duplications, gene family phylogenies, and gene positions provides a method to evaluate contributions of tandem duplication and segmental genome duplication in the generation and maintenance of gene families. These differences appear to correspond meaningfully to differences in functional roles of the members of the gene families.
There is a lack of agreement on the distribution of islet amyloid polypeptide (IAPP) in the pancreases of healthy and diabetic subjects. Therefore, a detailed morphometrical and immunohistochemical study was performed to obtain information on the distribution of cells expressing insulin, glucagon, somatostatin, pancreatic polypeptide (PP), and IAPP in the pancreases of non-diabetic (n=4) and diabetic individuals (n=6). In the non-diabetic cases, beta-cells contributed to approximately 64%, alpha-cells to 26%, delta-cells to 8%, PP cells to 0.3%, and IAPP cells to 34% of the islet cell population. The ratio of IAPP/insulin was approximately 1:2. In diabetic cases, beta-cells were decreased by 24%, and IAPP was decreased by 57%. The alpha- and delta-cells were increased by 40% and 58%, respectively. IAPP/insulin ratio was decreased by 41%. Thus, only 50% of the beta-cells in non-diabetics and only 30% in diabetics coexpressed IAPP. In diabetics, more delta-cells coexpressed IAPP than in non-diabetics. The results seem to argue against the notion that the secretion of IAPP is increased in diabetics. It is possible that an increase in somatostatin and glucagon plays a greater role in diabetes than IAPP.
To obtain quantitative results on scattered radiation produced in a patient by externally applied x-rays or gamma rays, the model of a pencil beam penetrating a water layer is used. By means of the Monte-Carlo method, the energy distribution of scattered photons in a plane parallel to the absorbing layer is calculated for primary photon energies from 60 to 1250 keV. This yields information on the distribution of single-scatter and multiple-scatter photons.
Butylated hydroxyanisole (BHA), a commonly used food additive, is a phenolic antioxidant. While metabolism of BHA has been studied in dog, man, rabbit and rat, information on tissue distribution is limited to rat and dog. Time dependent distribution and elimination of 3H-BHA following a single oral dose of 50 mg/kg body weight in female Swiss-Webster mice were investigated. Animals were sacrificed at time intervals up to 168 h after dosing. Levels of 3H were determined by liquid scintillation counting in the following tissues: brain, blood, serum, fat, heart, kidney, liver, lung, skeletal muscle and spleen. In most tissues the decline of BHA (log) was nonlinear with respect to time; a biphasic, post-absorptive aspect was observed. The highest 3H activity was noted in kidney and liver 15 min after dosing. The lowest activity was in fat. In addition, a peak 3H activity was recorded at 3 and 10 h after dosing for the blood and brain, respectively. Distribution of the 3H-BHA in mouse organs is similar to that in rat.