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PubMed1978

Occurrence and fate of organic and inorganic contaminants in marine animals.

Most chemical contaminants occur in highest concentrations in coastal waters, often maximized in very localized areas. In general, this situation represents the exposure pattern for marine animals. However, the availability of contaminant to an organism depends not only on its concentration but also on its chemical nature, its physical state, and whether the source of exposure is the surrounding seawater or the diet. Depending on the type of exposure, uptake occurs across absorptive surfaces, such as those of the respiratory apparatus or gastrointestinal tract, where selectivity may occur, even among neighboring homologs. Deposition in tissues, accumulation, degradation, or depuration depends on tissue type, metabolic processes, detoxification mechanisms, and the adaptive status of a particular animal. This hypothesis is examined briefly for hydrocarbons, pesticides, other miscellaneous organic contaminants, heavy metals, and radionuclides. It is concluded that most data relate to occurrence and distribution. Considerably less information is available on the underlying biochemical processes.

Animals↗
PubMed1982

Biochemical profiles of membranes from x-ray and neutron diffraction.

X-ray and neutron diffraction methods provide some information about the distribution of mass in biological membranes and lipid-water systems. Scattering density profiles obtained from these systems, however, usually are not directly interpretable in terms of the relative amounts of chemical constituents (e.g., lipid, protein, and water) as a function of position in the membrane. We demonstrate here that the combined use of x-ray and neutron-scattering profiles, together with information on the total amounts of each of the major membrane components, are sufficient to calculate unambiguously the volume fractions of these components at well-defined regions of the lamellar unit. Three cases are considered: a calculated model membrane pair, dipalmitoylphosphatidylcholine-water multilayers, and rabbit sciatic nerve myelin. For the model system, we discuss the limitations imposed by finite resolution in the diffraction patterns. For the lipid-water multilayers, we calculate water volume fractions in the hydrocarbon tail, lipid headgroup, and interlamellar regions; estimates of these values by various methods are in good agreement with our results. For the nerve myelin, we predict new results for the distribution of protein through the membrane.

Animals↗
PubMed2005

Interpretation and evaluation of the gamma index and the gamma index angle for the verification of IMRT hybrid plans.

In IMRT, the method for a quantitative comparison of two-dimensional dose distributions is still under development. The gamma evaluation method proposed by Low et al is the most accepted approach and has been adapted by many groups. Based on the concept of Low et al we developed a software tool with an intelligent search algorithm to minimize the calculation time. For the interpretation of deviations a y angle distribution and other tools (dose difference map, profiles, y area histograms, etc) are integrated in the software package. Ten hybrid plans are included in the verification study containing 6 IMRT head and neck cases, 2 IMRT prostate cases and one IMRT paravertebral case as well as a standard uniform intensity conformal 4 field box treatment for comparison. IMRT plans are realized with a segmental MLC delivery technique. The fields of a hybrid plan are applied at once and dose distributions are measured with films in three planes of a verification phantom. All y vector calculations are based on a 3% dose criterion and a 3 mm DTA acceptance criterion. The mean value gamma(mean) (mean value in the y distribution) of the various IMRT plans is 0.45+/-0.10 (1 SD). On average, the percentage of points exceeding the acceptance criteria of gamma < or = 1 (gamma > 1) is 5.8+/-5.4% (1 SD). The mean value of gamma 1% (1% of points have an equal or higher gamma value) is 1.47+/-0.59 (1 SD) for IMRT plans. In 5 out of 27 planes, gamma > 1 is substantially larger than the average. This is also indicated in gamma area histograms. Planes with large areas outside the tolerance criteria were further evaluated using gamma angle distributions. This additional information indicates that the large areas with high gamma values are dominated by the dose difference. It is shown that the deviations are influenced by tongue and groove effects. From the statistical evaluation of gamma values (e.g. gamma area histogram), acceptance criteria for IMRT hybrid plans can be defined. For the interpretation of the gamma maps, distributions of the gamma angle and traditional evaluation methods, such as dose profiles, are still very useful.

Algorithms↗
PubMed1999

Bridging the gap: linking a legacy hospital information system with a filmless radiology picture archiving and communications system within a nonhomogeneous environment.

A health level 7 (HL7)-conformant data link to exchange information between the mainframe hospital information system (HIS) of our hospital and our home-grown picture archiving and communications system (PACS) is a result of a collaborative effort between the HIS department and the PACS development team. Based of the ability to link examination requisitions and image studies, applications have been generated to optimise workflow and to improve the reliability and distribution of radiology information. Now, images can be routed to individual radiologists and clinicians; worklists facilitate radiology reporting; applications exist to create, edit, and view reports and images via the internet; and automated quality control now limits the incidence of "lost" cases and errors in image routing. By following the HL7 standard to develop the gateway to the legacy system, the development of a radiology information system for booking, reading, reporting, and billing remains universal and does not preclude the option to integrate off-the-shelf commercial products.

Computer Communication Networks↗
PubMed2001

X-ray microanalysis of cryopreserved human skin to study the effect of iontophoresis on percutaneous ion transport.

PURPOSE: To study at the ultrastructural level which part of the skin is associated with percutaneous iodide transport by passive diffusion and iontophoresis. METHODS: Following passive diffusion or iontophoresis of iodide, the morphology and the ion distribution of the skin was preserved by rapid freezing. The skin was kept frozen until and during examination by transmission electron microscopy (TEM) and X-ray microanalysis (XRMA). The intrinsic electron absorbing characteristics of cryopreserved skin allow direct TEM examination without additional staining. XRMA can be used to obtain in a relatively nondestructive way in situ information on ion distributions across the skin. RESULTS: After passive diffusion, iodide was mainly found in the stratum corneum (SC), whereas there was little iodide in the viable epidermis. Iontophoresis up to 300 microA/cm2 did not significantly affect this distribution. With iontophoresis at 1,000 microA/cm2, the amount of iodide increased dramatically and was equally distributed over the SC and viable epidermis. The presence of iodide in the SC suggests that iodide is present inside corneocytes. CONCLUSIONS: Iontophoresis up to 300 microA/cm2 does not significantly perturb skin structures in contrast to iontophoresis at 1,000 microA/cm2. The presence of iodide inside corneocytes suggests the possibility of transcellular percutaneous iodide transport.

Administration, Cutaneous↗
PubMed1999

Identification and mapping of novel tumor suppressor loci on 6p in diffuse large B-cell non-Hodgkin's lymphoma.

Allelic deletions have been thought to be indicators of the presence of tumor suppressor genes (TSGs). As indicated by this allelotype study using 39 highly informative microsatellite markers distributed among all autosomal chromosomes, frequent loss of heterozygosity (LOH) has been found at 6p in B-cell non-Hodgkin's lymphoma. To identify the commonly deleted regions (CDRs), we performed fine deletion mapping using 26 highly polymorphic microsatellite markers on 6p. The most frequent LOH occurred at D651721, where 9 of 18 of the informative cases (50%) had allelic losses. Seventeen of 32 cases (53%) exhibited LOH at least at one locus on 6p. Ten of these 17 cases showed interstitial deletions, and their LOH patterns indicated two CDRs on 6p; one between D6S1721 and D6S260 (at 6p23-24), and the other between D6S265 and D6S291 (at 6p21). The genetic distance of both CDRs was 6 cM. The CDKN1A (p21) gene is reported to be located within the interval of the CDR at 6p21, but no mutation of the gene was found in these 32 patients. These data suggested that these two loci might harbor novel putative TSGs responsible for the pathogenesis of malignant lymphoma. We have constructed a contig of yeast artificial chromosome (YAC) clones spanning the most frequent CDR at 6p23-24. This YAC contig can be used for fine physical mapping of the region and cloning of candidate TSGs.

Adolescent↗
PubMed2001

A novel approach for evaluating level, frequency and duration of lumbar posture simultaneously during work.

OBJECTIVES: Electrogoniometers are used to collect continuous information on postural distributions among workers. Enormous quantities of data are generated that have to be reduced to meaningful parameters (angle, frequency, and duration). In this study we propose statistical models to determine these essential characteristics of postural load on nurses, housekeepers, and office workers. METHODS: A direct registration of the lumbar posture was made over a workday with an inclinometer. An exposure variation analysis was used to summarize information on the angle of trunk flexion, the time period of maintained postures, and the percentage of worktime in a data matrix. A hierarchical regression analysis was used to compare these characteristics among nurses (N=64), housekeepers (N=16), and office workers (N=27). RESULTS: The occupational groups did not differ for either frequency or duration of trunk flexion over 30 degrees since frequency and duration were inversely related. Nurses experienced longer worktimes than the office workers did for trunk flexion between 30 and 70 degrees maintained <5 seconds, whereas office workers experienced longer worktimes in smaller angles (< 30 degrees) for longer periods. Comparable differences in the distributions of postural load were found between housekeepers and office workers. CONCLUSIONS: This study describes the use of hierarchical models in analyses of the exposure level, frequency, and duration of postural load simultaneously and offers an alternative to conventional ergonomic analysis in which the dynamics of exposure are often ignored. The distinction in postural load between nurses or housekeepers and office workers is best determined by the combination of trunk angle and time period.

Biomechanical Phenomena↗
PubMed2000

Hypoxia and necrosis in rat 9L glioma and Morris 7777 hepatoma tumors: comparative measurements using EF5 binding and the Eppendorf needle electrode.

PURPOSE: The purpose of this study was to assess the presence of tumor hypoxia using two independent techniques: binding of the 2-nitroimidazole EF5 and Eppendorf needle electrode measurements. The distribution of tumor hypoxia was assessed with respect to tumor necrosis in corresponding histological studies. METHODS AND MATERIALS: Each of several rats bearing a subcutaneous 9L glioma or Morris 7777 hepatoma tumor was given EF5 i.v. to a final, whole-body concentration of 100 microM. About 2.5 h later, each rat was anesthetized, and needle electrode measurements were made in the tumor along 1-5 tracks (30-200 individual measurements). At 3 h post-EF5 injection, the tumor was excised and frozen. Frozen sections were analyzed for the presence and distribution of binding of EF5 and necrosis using immunohistochemical techniques followed by staining with hematoxylin and eosin (H&E). The histochemical analysis and electrode readings in similar regions of the tumor were compared. RESULTS: Electrode measurements were taken at 0.4-mm intervals along one-dimensional tracks, whereas EF5 binding measurements from tissue sections contained two-dimensional information at high spatial resolution ( approximately 2.5 micro). The EF5 measurements showed greater spatial heterogeneity than did the electrode measurements. In tumor regions with minimal necrosis, needle tracks with relatively high pO(2) readings were usually found to contain relatively low EF5 binding, and vice versa. Because EF5 binding is inversely related to tissue pO(2), this result was expected. The expected inverse correlation of the two techniques was most disparate in necrotic tumor regions (confirmed by H&E staining), where needle electrode measurements showed low to zero pO(2) values, but little or no EF5 binding was found. CONCLUSION: The two methods compared in this study operate in fundamentally different ways and provide substantially different information. EF5 binding provided detailed spatial information on the distribution of hypoxia in viable tumor tissue. There was no EF5 binding in necrotic tumor tissue because cells in such tissue were unable to metabolize the drug. In contrast, output from the needle electrode method appeared to represent a "track-average" tissue pO(2) and did not distinguish between extreme hypoxia and either macroscopic or microscopic necrosis. At the present time, the importance of tumor necrosis in determining treatment response is unknown. However, our data suggest that the Eppendorf needle electrode technique will overestimate the presence of hypoxia. Both techniques are potentially limited by sampling errors in tumors with heterogeneous distributions of hypoxia.

Animals↗
PubMed2001

Support services in Denmark for parents of children who are deaf or hard of hearing--a national survey.

To collect parents' evaluation of support services in Denmark, questionnaires were distributed to parents of children who are deaf or hard of hearing. Some few results and conclusions are picked out in the article below. Parents' comments show some recurrent features: counselling must be offered and should be offered immediately after confirmed diagnosis, there is a need for psychological support at an early time, for qualified advisers, for written information to be distributed, and for co-operation between advisers of the family.

Adolescent↗
PubMed2005

Structure of the excitatory receptive fields of infragranular forelimb neurons in the rat primary somatosensory cortex responding to touch.

We quantitatively studied the excitatory receptive fields of 297 neurons recorded from the forelimb infragranular somatosensory cortex of the rat while touch stimuli were applied to discrete locations on the forelimbs. Receptive fields were highly heterogeneous, but they were regulated, on average, by an underlying spatio-temporal structure. We found the following. (i) Neurons responded with decreasing magnitude and increasing latency when the stimulus was moved from the primary location to secondary locations and to far ispilateral locations of their excitatory receptive fields, displaying smooth transitions from the primary location to secondary locations. (ii) Receptive field patterns revealed functional connectivity between the digits and ventral palm, which did not depend on whether the digits were stimulated dorsally or ventrally. (iii) The structure of the receptive fields (i.e. the neural responses to stimulation of secondary locations compared to the neural responses to stimulation of the primary location), reflected cortical (rather than body) distances. (iv) There was a functional separation between the forepaw and the rest of the forelimb. Namely: if the primary location was in the digits or palm, secondary locations were biased toward the digits and palm; if the primary location was in rest of the forelimb, secondary locations appeared equally distributed over forelimb, digits and palm. (v) More than 40% of neurons extended their receptive field to the ipsilateral forelimb, without any evident spatial organization. Overall, the stimuli evoked approximately 3 times more spikes from secondary responses than from primary responses. These results suggest that a rich repertoire of spatio-temporal responses is available for encoding tactile information. This highly distributed receptive field structure provides the electrophysiological architecture for studying organization and plasticity of cortical somatosensory processing.

Animals↗
PubMed1991

The status of medical education for black Americans.

Health-care priorities are changing throughout the United States, and the quality of American medicine is dependent on the quality of medical education. While a surplus of doctors is anticipated, a shortage of minority doctors remains. Published data sources provide information on enrollment, distribution, and specialties of black Americans in medical education programs. These data provide understanding of the process that has created the shortage of blacks in medicine. The tabular data suggest that the proportion of blacks in medical education programs has remained very low over time, and in some cases, it has actually declined. Funding needs, recruitment efforts, and educational information are essential considerations in changing the racial make-up of medical education and health care.

Black or African American↗
PubMed2002

Matrilin-3 in human articular cartilage: increased expression in osteoarthritis.

OBJECTIVE: Matrilin-3 is a member of the recently described matrilin family of extracellular matrix proteins containing von Willebrand factor A-like domains. The matrilin-3 subunit can form homo-tetramers as well as hetero-oligomers together with subunits of matrilin-1 (cartilage matrix protein). It has a restricted tissue distribution and is strongly expressed in growing skeletal tissues. Detailed information on expression and distribution of extracellular matrix proteins is important to understand cartilage function in health and in disease like osteoarthritis (OA). METHODS: Normal and osteoarthritic cartilage were systematically analysed for matrilin-3 expression, using immunohistochemistry, Western blot analysis, in situ hybridization, and quantitative PCR. RESULTS: Our results indicate that matrilin-3 is a mandatory component of mature articular cartilage with its expression being restricted to chondrocytes from the tangential zone and the upper middle cartilage zone. Osteoarthritic cartilage samples with only moderate morphological osteoarthritic degenerations have elevated levels of matrilin-3 mRNA. In parallel, we found an increased deposition of matrilin-3 protein in the cartilage matrix. Matrilin-3 staining was diffusely distributed in the cartilage matrix, with no cellular staining being detectable. In cartilage samples with minor osteoarthritic lesions, matrilin-3 deposition was restricted to the middle zone and to the upper deep zone. A strong correlation was found between enhanced matrilin-3 gene and protein expression and the extent of tissue damage. Sections with severe osteoarthritic degeneration showed the highest amount of matrilin-3 mRNA, strong signals in in situ hybridization, and prominent protein deposition in the middle and deep cartilage zone. CONCLUSION: We conclude that matrilin-3 is an integral component of human articular cartilage matrix and that the enhanced expression of matrilin-3 in OA may be a cellular response to the modified microenvironment in the disease.

Adult↗
PubMed2003

Healthy life expectancy in Hong Kong Special Administrative Region of China.

Sullivan's method and a regression model were used to calculate healthy life expectancy (HALE) for men and women in Hong Kong Special Administrative Region (Hong Kong SAR) of China. These methods need estimates of the prevalence and information on disability distributions of 109 diseases and HALE for 191 countries by age, sex and region of the world from the WHO's health assessment of 2000. The population of Hong Kong SAR has one of the highest healthy life expectancies in the world. Sullivan's method gives higher estimates than the classic linear regression method. Although Sullivan's method accurately calculates the influence of disease prevalence within small areas and regions, the regression method can approximate HALE for all economies for which information on life expectancy is available. This paper identifies some problems of the two methods and discusses the accuracy of estimates of HALE that rely on data from the WHO assessment.

Adolescent↗
PubMedDate not supplied

[Written information: evaluation of an informative leaflet for patients undergoing colonoscopy].

Client teaching and information on medical procedures and care organisation is recognised as one of the most important tasks for the nurse. The information must be complete, detailed, and personalized according to the client culture and learning capacity. To address these points, an information booklet has been designed to inform clients undergoing colonoscopy in the gastroenterology unit of Azienda Ospedaliera Careggi, Florence. The booklet, together with a multiple choice questionnaire aimed at evaluating clients' satisfaction with the information provided, was distributed to 100 clients undergoing a colonoscopy over a two-month period in 1998. The results of the survey suggest that the booklet has been instrumental in client learning about the procedure, as shown by the high positive satisfaction response provided to the questionnaire. Moreover, contents provided are clear and easy to understand. Clients would like to have specifically detailed information on the way the exam is performed, on its duration (22%) and on the disinfection procedures (21%). At present, all the patients booked for colonoscopy receive the booklet in their homes.

Adult↗
PubMed2002

Measured variation in boron loads reaching European sewage treatment works.

Per capita boron loads reaching 48 sewage treatment works (STWs) in The Netherlands, Germany, Italy, and the UK have been determined from monitoring data. These have been compared with the per capita input predicted from boron in detergents, as determined from detergent product sales data. The resulting distribution of the ratios of measured boron to boron predicted from consumer usage has a 90th percentile of less than 1.5. Boron has previously been shown to be a good marker for substances contained in detergent products, as it cannot be biodegraded and is not substantially adsorbed in the sewer, and there is little or no removal during sewage treatment processes. The monitoring information on the distribution of boron loads found at the different STWs should thus be indicative of the distribution of other substances released to the environment by detergent products, as specified by the relevant industrial category (IC 5-personal/domestic) in the Technical Guidance Documents. Variation in detergent product consumption figures from 18 European countries is also low, with the country with the highest per capita detergent consumption having only 1.3 times the European average detergent use. Thus the present practice of determining a "reasonable worst case" by multiplying the average per capita consumption by a factor of four to account for geographic differences in distribution, is considered to be inappropriate. This should be replaced by a factor of less than two, which combines within country and between country variations to provide a reasonable worst case approximation of the load reaching the sewage treatment facility.

Boron↗
PubMed1991

Investigating the effect of stimulus range on attribute weight.

Classic economic theories of choice assume that trade-offs are made consistently and are not swayed by irrelevant contextual variables. One possible source of trade-off inconsistency is investigated by asking whether attribute weights are affected by variations in the range of the stimuli presented. Ss should be influenced by the range of the stimuli only when distributional characteristics provide information about the value of the stimuli. In six experiments, Ss made judgments when the range (a) did not provide information about the value of the scores on the scales, (b) might provide such information, and (c) certainly provided this information. In Experiments 1-5, Ss were not influenced by the range of the stimuli. The only exception was Experiment 6, which required Ss to judge hypothetical job candidates on the basis of stimulus scales with which the Ss had no previous experience. In this experiment the meaning of the scales was determined entirely by the location of each stimulus within the presented distribution. In general, the results support the classical view of decision making: that attribute weights exist independent of situational demands, and that Ss' judgments are not influenced by irrelevant stimuli.

Adult↗
PubMed2003

Spatial targeting of interventions against malaria.

Malaria transmission is strongly associated with location. This association has two main features. First, the disease is focused around specific mosquito breeding sites and can normally be transmitted only within certain distances from them: in Africa these are typically between a few hundred metres and a kilometre and rarely exceed 2-3 kilometres. Second, there is a marked clustering of persons with malaria parasites and clinical symptoms at particular sites, usually households. In localities of low endemicity the level of malaria risk or case incidence may vary widely between households because the specific characteristics of houses and their locations affect contact between humans and vectors. Where endemicity is high, differences in human/vector contact rates between different households may have less effect on malaria case incidences. This is because superinfection and exposure-acquired immunity blur the proportional relationship between inoculation rates and case incidences. Accurate information on the distribution of malaria on the ground permits interventions to be targeted towards the foci of transmission and the locations and households of high malaria risk within them. Such targeting greatly increases the effectiveness of control measures. On the other hand, the inadvertent exclusion of these locations causes potentially effective control measures to fail. The computerized mapping and management of location data in geographical information systems should greatly assist the targeting of interventions against malaria at the focal and household levels, leading to improved effectiveness and cost-effectiveness of control.

Africa↗
PubMed1987

Remittances and income distribution.

"The paper studies the effects of [foreign] remittances on the pattern of income distribution in Yugoslavia. It is found that remittances raise the Gini coefficient, although unequally as between different social groups. One reason may be that in social groups where the diffusion of information is relatively even (as among urban households) migration is more uniform across income groups than it is in social groups where the access to information depends primarily on the level of income (e.g. rural households). In the latter groups distribution of migrants is more skewed towards higher income groups and remittances increase the level of inequality more substantially." Data are from household surveys conducted in Yugoslavia in 1973, 1978, and 1983.

Communication↗