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Biomedical subjects

D Weber

Publications and source records attributed to D Weber.

At least 145 records · Page 8Linked to original sources
PubMed1989

Reliability of a urine dipstick in emergency department patients.

We conducted a study to examine whether a negative Chemstrip 9 result for leukocyte esterase and nitrite would reliably exclude an abnormal microscopic examination of the urine of emergency department patients. Three hundred urine specimens were subjected to Chemstrip 9 evaluations and full microscopic examinations in the microscopy laboratory. As the microscopy laboratory examination identified lower WBC and bacteria counts, increasing numbers of false-negative urine dipsticks results occurred. The results of our study reveal that the nitrite and leukocyte esterase assays miss significant microscopic findings with corresponding clinical pathology, with the nitrite examination being the less sensitive of the two tests. Based on our results, we believe it would not be prudent to use the Chemstrip 9 dipstick in the ED to exclude the presence of WBC and bacteria in the urine.

Bacteriuria↗
PubMed1989

Mapping RFLP loci in maize using B-A translocations.

Plants hypoploid for specific segments of each of the maize (Zea mays L.) chromosomes were generated using 24 different B-A translocations. Plants carrying each of the B-A translocations were crossed as male parents to inbreds, and sibling progeny hypoploid or not hypoploid for specific chromosomal segments were recovered. Genomic DNAs from the parents, hypoploid progeny, and nonhypoploid (euploid or hyperploid) progeny for each of these B-A translocations were digested with restriction enzymes, electrophoresed in agarose gels, blotted onto reusable nylon membranes, and probed with nick-translated, cloned DNA fragments which had been mapped previously by restriction fragment length polymorphism (RFLP) analysis to the chromosome involved in the B-A translocation. The chromosomal segment on our RFLP map which was uncovered by each of the B-A translocations was determined. This work unequivocally identified the short and long arms of each chromosome on this map, and it also identified the region on each chromosome which contains the centromere. Because the breakpoints of the B-a translocations were previously known on the cytological and the conventional genetic maps, this study also allowed this RFLP map to be more highly correlated with these maps.

Centromere↗
PubMed1989

[Measurement of handicap in the community: a micro survey in a French village].

Handicap is the result of a process initiated by an underlying disease, an accident or an abnormality, which leads to a functional deficit in various situations of everyday life. This definition, derived from the International Classification of Impairments, Disabilities, and Handicaps (ICIDH), reflects the desire of the elderly and the handicapped for social integration. It may also form the conceptual basis for analysis of the capacities of individuals and populations. To this end, a micro-survey was conducted in a homogeneous village community of 532 people aged 1-92 years. This study was of the ergonomic type, accompanied by a questionnaire on perceived restrictions and handicaps, and carried out transversely over a period of one month (94.7% participation). The specific objectives of the study were to obtain a reliable functional representation of the population of the village, comparing self-assessment of functional capacity with observed performance, and analysing the effects of age on capacity. The copious data collected in the areas of locomotion, prehension and communication have provided a detailed functional profile of the population studied. These data may be transposed to particular environments, such as transport, housing, school or work, and may serve as a basis for comparisons. The difficulties encountered by subjects in the tests were closely correlated with the situations simulated by the tests. Subjective estimation of handicap proved to be reliable in comparison with actual performance, especially for tests of mobility and highly demanding situations. Estimation of the presence of a handicap increased with age. The deterioration in performance observed was proportional to age, but can be perceived to begin early, at about 30-40 years. Disability-free life expectancy (DFLE) could be an interesting indicator in so far as it appears to be sensitive to the confrontation of individual functional capacities with the environment. However, it is important that any disability used as a basis for calculation should be measured with maximum precision. A community survey of this kind is thus particularly useful for ergonomic purposes, but is also valuable for the planning of medical and social assistance at the local level in the areas of disability and handicap. The combination of observation and listening to people, with an interview, appears to be fruitful and reliable. Single studies of well-targeted samples of the population, or, alternatively, of larger and more significant populations, would be desirable in public health, since the epidemiological approach to handicap has hitherto been essentially focused on diagnosis and medical evaluation.

Activities of Daily Living↗
PubMed1989

[The number of active sweat glands (PSI, palmar sweat index) as a psychophysiologic parameter].

Two laboratory studies were carried out to assess the behavior of the active palmar sweat glands in both an active and a passive coping situation. Stressor in study I was watching a distressing film, in study II mental arithmetic. Subjects were male students, 17 in experiment I, 20 in experiment II. Both experiments involved a 10-minute baseline phase, a 10-minute stress period, and a follow-up of 10 minutes. PSI was assessed at 90-sec intervals and averaged across phases, as were readings in SCL, SCR, heart rate, diastolic and systolic blood pressure. PSI could be determined in 16 subjects of each study. In both experiments PSI increased significantly from baseline to stress (p less than 0.1%) and decreased from stress to follow-up (p less than 0.1%), and thus proved to be the most sensitive indicator for stress. The interrater reliability for counting the number of active sweat glands was high when the area for evaluation was defined unambiguously. Since the assessment of the PSI does not require a sophisticated technology and is thus also applicable in field research, we suggest giving more consideration to this variable.

Adult↗
PubMed1988

Identification of specific residues of human interleukin 2 that affect binding to the 70-kDa subunit (p70) of the interleukin 2 receptor.

Analogs of interleukin 2 containing defined amino acid substitutions and deletions were assayed for bioactivity and for competitive binding to the high-affinity human interleukin 2 receptor complex and its two component subunits, a 55-kDa subunit (p55 or TAC) and a 70-kDa subunit (p70). Substitution of Asp20 or deletion of Phe124 resulted in inactive analog proteins that were unable to interact with the high-affinity p55/p70 complex or the intermediate-affinity p70 subunit of the interleukin 2 receptor. These analogs, however, retained the capacity to compete for binding to the low-affinity p55 subunit. The presence of the carboxylic acid in the side chain of Asp20 was necessary for effective binding to the p70 protein. In contrast, substitution of Trp121 and Leu17 created analogs that were inactive in the bioassay and all three binding assays. The effects of these mutations on protein conformation were assessed by circular dichroism. These results demonstrate that specific residues in the NH2 and COOH termini of interleukin 2 are crucial for its structure and activity.

Binding, Competitive↗
PubMed1988

Variable estimates of serum growth hormone concentrations by different radioassay systems.

Many different assays are being used to measure serum GH concentrations in children with disorders of growth. We assessed four readily available methods to determine the comparability of the immunopotency estimates: standard double antibody RIA with pituitary standards from the National Hormone and Pituitary Program (assay 1) and from a commercial source (assay 2), a double antibody RIA with serum standards (assay 4), and a commercial immunoradiometric assay (assay 3). There was a high degree of relative correlation between assays (r = 0.95-0.98), but absolute potency estimates differed. Assays 1 and 2 were almost identical. Assay 3 yielded serum GH levels about 65% those of assay 1 or 2 and 80% those of assay 4. Assay 4 gave intermediate values between the low readings in assay 3 and higher values in assay 1 and 2. We conclude that substantial variation occurs in potency estimates in different GH assays. Such differences can affect the interpretation of many GH provocative and sampling studies.

Child↗
PubMed1988

Authoritative medical direction can assure cost-beneficial bronchial hygiene therapy.

A bronchial hygiene (BH) program for non-Intensive Care Unit (ICU) patients in which regimens are determined by respiratory therapy evaluators is described. The medical director of Respiratory Care was given control of orders by the medical staff and assumed responsibility for the evaluators' decisions. Patterns of BH utilization were analyzed for 24 months and were compared with BH utilization patterns in a preceding similar program in which orders were controlled by primary care physicians. Extra-ICU BH therapy (BHT) decreased by 61 percent and neither morbidity nor mortality was undesirably affected. Cost savings exceeded $250,000 per year. Authoritative medical direction of such a program results in cost-beneficial utilization of BHT, provides an excellent guide for resident physicians to learn appropriate utilization of such therapy, provides for quality assurance and medical necessity documentation, and is well accepted by the medical staff.

Cost-Benefit Analysis↗
PubMed1988

"High-resolution" mini-two-dimensional gel electrophoresis automatically run and stained in less than 6 h with small, ready-to-use slab gels.

Although two-dimensional (2-D) gel electrophoresis is one of the most powerful techniques for analyzing protein mixtures, its application in routine clinical laboratories is currently limited, because it is time-consuming, complex, and relatively expensive. Here we describe a method for automatically running and staining "high-resolution" mini 2-D electrophoresis gels in less than 6 h, by using "ready-to-use" slab gels and a PhastSystem electrophoresis apparatus. We present 2-D gel electrophoretograms of 25 nL of plasma, as well as their automatic computer analysis. For comparison, a conventional 2-D gel electrophoresis profile of 200 nL of a plasma sample is shown. The technique is easy to perform, highly sensitive, rapid, and potentially useful in semi-routine clinical chemistry laboratories.

Autoanalysis↗
PubMed1987

Gas chromatographic-mass spectrometric determination of ethyl carbamate in alcoholic beverages.

A sensitive and specific method based on gas chromatography-mass spectrometry for the quantitative determination of ethyl carbamate in table wines, fortified wines (such as ports and sherries), distilled spirits, brandies and liqueurs has been developed. Three characteristic ions from ethyl carbamate [m/z 89 (molecular ion), 74 and 62] were monitored in the selected-ion monitoring (SIM) mode. The lowest detection limit (based on the response on the m/z 62 ion) was estimated to be 0.5 ng/g (ppb). Additional confirmation techniques, including high-resolution SIM, and methane or isobutane chemical ionization are described.

Alcoholic Beverages↗
PubMed1987

Reliability and practicability of the fluorometric-fluoroenzymatic histamine determination in pathogenetic studies on peptic ulcer: detection limits and problems with specificity.

Histamine, among various "biologic-physiologic" abnormalities, is considered as a pathogenetic factor in chronic duodenal ulcer disease. The 10-30 per cent difference between its concentration in gastric and duodenal mucosa of patients compared to healthy controls, however, has to be demonstrated to be specific for the disease. It has to be shown to be neither a methodological artefact nor a common effect, concomitant factor or consequence. This study, after a series of pathogenetic trials examines systematic errors (biases) in the fluorometric-fluoroenzymatic histamine assay under the conditions of field studies including tests on specificity over a time period of 10 years. It concentrates on sensitivity (detection limits) and specificity of a standard technique described herein. A modified Shore procedure for large scale assays in human biopsies was developed including reference luminescence values for all reagents, cleaning material and glassware, reduction of OPD concentration to 0.05%, purification of n-heptan, omission of centrifugation steps in the extraction procedure and use of 2 ml 1 M HClO4 in the homogenization step to prevent losses of histamine due to adherence to the mechanical homogenizer. This assay was sensitive enough to measure histamine without difficulty in any biopsy taken. The detection limit was 3 ng/biopsy, but the smallest quantities of the amine ever obtained were 10.6 and 18.3 ng/biopsy (depending on both histamine content and biopsy weight). A series of problems had to be solved both in achieving and demonstrating specificity. It had to be defined not only for the assay in general, but also for assessing the difference in histamine content between ulcer patients and healthy controls. Exogenous more than endogenous fluorescing material interfering with the determination had to be excluded. A series of pitfalls were detected which had to be overcome in demonstrating the specificity of the assay by physicochemical and enzymatic tests. The specificity of the identification tests was more often impaired than the histamine assay itself. Fluorescing material interfering with the assay occurred in the homogenization, extraction and condensation steps, was found in water, OPD, the organic solvents, the cleaning material and in all kinds of plastic vessels. Plasticizers were shown by physicochemical characteristics including fluorescence spectra to be most likely responsible for this interfering material. Rules were developed to exclude such hazards in specificity in longterm pathobiochemical studies. Enzymatic identification test were applied to exclude endogenous fluorecing substances interfering with the standard technique. Simil

Biopsy↗
PubMed1987

The routine analysis of some specific isomers of polychlorinated biphenyl congeners in human milk.

A mixture of 14 polychlorinated biphenyl (PCB) isomers of various congeners, representing approximately 70% of all human milk PCBs reported in the literature, was made up to identify and approximate their residues in human milk. Individual isomer levels varied from 5 to 103 nanograms per gram of milkfat with the 2,2',4,4',5,5'-hexachlorobiphenyl isomer as the major PCB contaminant of human milk. PCB isomer numbers 74, 118, 153, 138 and 180 made up approximately 75% of all PCBs as measured by this mixture. There was close agreement of total PCB isomer content in breast milk between electron capture gas chromatography and gas chromatographic mass spectrometry determinations. A major interference was encountered however for PCB isomer no. 52, whose residue level in the breast milk was approximately 3 X higher by gas liquid chromatography than by mass spectrometry.

Canada↗
PubMed1987

The functional aptitude of a natural sample of population. A new approach to handicap (Saint Cyr-sur-le-Rhône, Sept. 1984).

A survey of the total population of a small rural village was undertaken to discern the amount of impairment and disability present, using both questionnaire and examination techniques. It was confirmed that the concept of disability was applicable to such populations and that it was related to age, at both extremes of life. There was a good correlation between self-reporting and examination of locomotor and sensory impairments but it was poor when applied to prehensile or dexterity skills. This survey showed that such techniques can be applied to populations. As yet the handicap code in the International Classification of Impairment, Disability and Handicap has not been related to this population but this is seen as an important next step in the proper understanding of chronic disability in the community.

Adolescent↗