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Biomedical subjects

J Katz

Publications and source records attributed to J Katz.

At least 379 records · Page 21Linked to original sources

The impact of professional football games upon violent assaults on women.

The relationship between the timing and outcomes of the Washington Redskins' football games and the frequency of admissions to hospital emergency rooms in northern Virginia is investigated. An OLS time series analysis is conducted, controlling for days of the week, months, years and special holidays for 1988-1989. The results indicate that the frequency of admissions of women victims of gun shots, stabbings, assaults, falls, lacerations and being struck by objects increases when the team wins. We hypothesize that many of these injuries are the result of battering and that having a favorite team win may act as a trigger for assault in some males. We suggest that viewing the successful use of violet acts may give the identifying fan a sense of license to dominate his surroundings.

Adult↗

Dental disease in the differential diagnosis of fever of unknown origin.

A patient with a one-year history of fever of unknown origin is presented. Extensive work-up failed to reveal the source of the fever. Treatment of periodontal infection resulted in complete cure, suggesting a cause-effect relationship. A possible role of Interleukin 1 (IL-1), universal pyrogen, in periodontal disease is suggested.

Adult↗

Tolerance of young infants to a single, large dose of vitamin A: a randomized community trial in Nepal.

A randomized, double-masked trial was carried out in rural Nepal to investigate the incidence and severity of acute side-effects among neonates ( < 1 month of age) and infants aged 1-6 months who received a large, oral dose of vitamin A (15,000 retinol equivalents (RE) (50,000 IU) and 30,000 RE (100,000 IU), respectively) or placebo (75 RE (250 IU) and 150 RE (500 IU), respectively) in oil. Infants (vitamin A group, n = 1461; controls, n = 1379) were assessed for vomiting, loose stools, fever, and irritability during the 24 hours before and after dosing. Fontanelles were palpated 24 hours after dosing. Neonates exhibited no excess risk of adverse side-effects after receiving 15,000 RE. Compared with controls the older infants who ingested 30,000 RE had a 1.6% excess rate of vomiting (95% confidence interval (CI): 0.2-3.0%) and a 0.5% excess rate (95% CI: -0.1 to 1.1%) in the occurrence of bulging fontanelles. There were no other significant differences in the older infants. The controlled, periodic distribution of a single 15,000 RE dose of vitamin A therefore confers no apparent acute risk to young infants; a 30,000 RE dose is associated with a minimum risk of transient, acute side-effects.

Age Factors↗

The effects of a six-week, low-intensity Nautilus circuit training program on resting blood pressure in females.

Twenty-six healthy, untrained females were studied to determine the effects of a low-intensity Nautilus circuit training program on resting systolic and diastolic blood pressure. Thirteen subjects who were in good health with no personal history or family history of cardiovascular disease participated in a six-week training program on the Nautilus circuit (14 exercises) and trained at 30% of maximum. Measurements in blood pressure were made before, during (three times per week) and after the study. Another group of 13 females served as controls. An attempt was made to determine if strength increase (due to circuit training) would have an affect on reducing resting systolic and diastolic blood pressure. The following changes occurred in the treatment group: (1) resting systolic blood pressure dropped significantly (from 113 to 99 mmHg) after training and (2) diastolic blood pressure dropped significantly from (70.9 to 62.0 mmHg) after training. However, there were no differences in these decreases between the exercise and control groups. The investigators concluded that low-intensity, resistive training should not increase blood pressure in white, healthy females, ages 18 to 28 years.

Adolescent↗

Anaesthetic interaction between thiopentone and ketamine.

The anaesthetic effect of thiopentone, ketamine and their combinations were studied in 150 patients of ASA Grades I and II. The ability to open eyes on command and purposeful motor response to noxious pressure on the trapezius muscle were used as endpoints of anaesthesia. Dose-response curves for thiopentone, ketamine and their combinations were determined with a probit procedure and compared with isobolographic analysis. The interaction between thiopentone and ketamine was found to be additive for both endpoints of anaesthesia.

Adult↗

Nifedipine-induced gingival hyperplasia.

Gingival hyperplasia is an adverse reaction of nifedipine therapy. Oral manifestations of this condition include enlarged and painful gingiva accompanied by spontaneous bleeding. Nifedipine-induced gingival hyperplasia may be reversible once a proper drug substitution is made. Two cases of gingival hyperplasia resulting from nifedipine are described and the drug's possible mode of action is discussed.

Adult↗

"The Fallacy of the Impartial Expert" revisited.

This article, in memory of Bernard Diamond, revisits his seminal editorial on the "Fallacy of the Impartial Expert." In a later article he formulated his thesis most succinctly: "There is no such thing as an impartial expert witness; the objectivity of the expert witness is largely a myth." I argue that the implications of his challenging assertion have as yet not been fully recognized. Ultimately, they also invite a revision of the American Academy of Psychiatry and Law's Guidelines for the Practice of Forensic Psychiatry. The Guidelines should emphasize more than they do experts' commitment to honesty and to informing fact finders about the extent and limits of their scientific knowledge, the facts on which their opinions are based, as well as the scientific and value assumptions that underlie their testimony.

Ethics, Medical↗

Stimulation of glycogen synthesis by proglycosyn (LY177507) by isolated hepatocytes of normal and streptozotocin diabetic rats.

The phenacylimidazolium compound LY177507 was shown by Harris et al. (Harris, R. A., Yamanuchi, K., Roach, P. J., Yen, T. T., Dominiani, S. J., and Stephens, T. W. (1989) J. Biol. Chem. 264, 14674-14680) to stimulate glycogen synthesis greatly in isolated rat hepatocytes. We extended studies with this compound, designated proglycosyn (Yamaguchi, K., Stephens, T. W., Chikadar, K., Depaoli-Roach, A., And Harris, R. A. (1991) Diabetes 40, (Suppl. 1) 102 (abstr.] employing hepatocytes from normal and streptozotocin diabetic rats. Proglycosyn is more effective than amino acids in stimulating glycogen synthesis. In cells incubated with glucose, lactate, or dihydroxyacetone the effect of glutamine and proglycosyn was synergistic. In cells incubated with glucose plus lactate, or glucose plus dihydroxyacetone, the stimulation by the two agonists was additive. Proglycosyn diverted the gluconeogenic flux from glucose to glycogen. The maximal rates of glycogen deposition attained in the presence of glutamine and proglycosyn from cells incubated with glucose plus lactate, or glucose plus dihydroxyacetone, where about 80 and 110 mumols/h/g of liver, respectively. Proglycosyn depressed glycogenolysis in hepatocytes of fed rats and stimulated glycogen synthesis from lactate and dihydroxyacetone. The incorporation of [U-14C]glucose and [U-14C]lactate in these cells occurred in the presence of glycogen breakdown or exceeded net production, indicating the occurrence of recycling of glycogen in hepatocytes of fed rats. Hepatocytes from fasted streptozotocin diabetic rats contained high levels of glycogen. Glycogenolysis was markedly depressed by proglycosyn. Glycogen synthesis from lactate and dihydroxyacetone in these cells was stimulated by glutamine and proglycosyn in a fashion similar to that in cells from fasted control rats, and the rates of glycogen synthesis were similar in cells of control and diabetic rats. With glucose as sole substrate, glutamine did not stimulate glycogen synthesis. When both agonists were present, there was a marked synergism and substantial glycogen formation. Streptozotocin diabetic rats prior to the onset of cachexia have a normal capacity for glycogen synthesis.

Animals↗

A population-based evaluation of glaucoma screening: the Baltimore Eye Survey.

The Baltimore Eye Survey was a population-based survey conducted from January 1985 to November 1988 among residents of east Baltimore, Maryland, who were 40 years of age or older. A total of 5,308 black subjects and white subjects received a comprehensive screening examination for glaucoma including tonometry, visual fields, stereoscopic fundus photography, and a detailed medical and ophthalmic history. Based on a definitive examination, a diagnosis of glaucoma of any type was made for 196 persons. Tonometry, cup:disc ratio, and narrowest neuroretinal rim width were evaluated for their ability to correctly classify subjects into diseased or nondiseased states. There were no cutoff values at which these variables provided a reasonable balance of sensitivity and specificity, separately or in combination. Logistic regression models were fit that included demographic and other risk factors. Sensitivities and specificities were calculated for varying cutoff levels on the distribution of predicted probabilities. There was no cutoff for which reasonable sensitivity and specificity were obtained. The authors conclude that the effectiveness of current techniques for glaucoma screening is limited.

Adult↗

Racial differences in the cause-specific prevalence of blindness in east Baltimore.

BACKGROUND: Bilateral blindness unrelated to simple refractive error is twice as prevalent among blacks as among whites, although the difference narrows among the elderly. The reasons for this race- and age-related pattern are uncertain. METHODS AND RESULTS: A randomly selected, stratified, multistage cluster sample of 2395 blacks and 2913 whites 40 years of age and older in East Baltimore underwent detailed ophthalmic examinations by a single team. We identified 64 subjects who were blind in both eyes. The leading causes of blindness were unoperated senile cataract (accounting for blindness in 27 of the total of 128 eyes), primary open-angle glaucoma (17 eyes), and age-related macular degeneration (16 eyes). Together, these three disorders accounted for 47 percent of all blindness in this sample. Unoperated cataract accounted for 27 percent of all blindness among blacks, among whom it was four times more common than among whites; whites were almost 50 percent more likely than blacks to have undergone cataract extraction before the age of 80 (P less than 0.002). Primary open-angle glaucoma accounted for 19 percent of all blindness among blacks; it was six times as frequent among blacks as among whites and began 10 years earlier, on average. By contrast, age-related macular degeneration resulting in blindness was limited to whites, among whom it was the leading cause of blindness (prevalence, 2.7 per 1000; 95 percent confidence interval, 1.2 to 5.4); it affected 3 percent of all white subjects 80 years of age or older. CONCLUSIONS: The pattern of blindness in urban Baltimore appears to be different among blacks and whites. Whites are far more likely to have age-related macular degeneration, and blacks to have primary open-angle glaucoma. The high rate of unoperated cataracts among younger blacks and among elderly subjects of both races suggests that health services are underused. Half of all blindness in this urban population is probably preventable or reversible.

Adult↗

Racial variations in the prevalence of primary open-angle glaucoma. The Baltimore Eye Survey.

OBJECTIVE: --To compare the prevalence of primary open-angle glaucoma between black and white Americans. DESIGN, SETTING, AND PARTICIPANTS: --The design was a population-based prevalence survey of a noninstitutionalized black and white population aged 40 years or older from the eastern and southeastern health districts of Baltimore, Md. A multistage random sampling strategy was used to identify 7104 eligible participants, of whom 5308 (2395 blacks, 2913 whites) received an ophthalmologic screening examination. Those with abnormalities were referred for definitive diagnostic evaluation. MAIN OUTCOME MEASURE: --Primary open-angle glaucoma was defined based on evidence of glaucomatous optic nerve damage, including abnormal visual fields and/or severe optic disc cupping, and was independent of intraocular pressure. MAIN RESULTS: --Age-adjusted prevalence rates for primary open-angle glaucoma were four to five times higher in blacks as compared with whites. Rates among blacks ranged from 1.23% in those aged 40 through 49 years to 11.26% in those 80 years or older, whereas rates for whites ranged from 0.92% to 2.16%, respectively. There was no difference in rates of primary open-angle glaucoma between men and women for either blacks or whites in this population. Based on these data, an estimated 1.6 million persons aged 40 years or older in the United States have primary open-angle glaucoma. CONCLUSIONS: --Black Americans are at higher risk of primary open-angle glaucoma than their white neighbors. This may reflect an underlying genetic susceptibility to this disease and indicates that additional efforts are needed to identify and treat this sight-threatening disorder in high-risk communities.

Adult↗

Islet-specific T-cell clones from nonobese diabetic mice express heterogeneous T-cell receptors.

Nonobese diabetic (NOD) mice spontaneously develop a T-cell-mediated autoimmune disease that is similar in many respects to insulin-dependent diabetes mellitus in humans. T-cell clones that specifically recognize pancreatic islet cell antigens can be derived from NOD mice, and most of these have been diabetogenic upon transfer to healthy recipients. We report herein the sequences of the T-cell receptor alpha and beta chains from four NOD-derived, islet-specific clones. The sequences are quite heterogeneous--in the junctional regions, specifically--so there seems to be little hope for treating this disease with specific anti-T-cell receptor reagents. This result contrasts with the strikingly restricted junctional region sequences reported for the receptors on clones derived from mice with experimental allergic encephalomyelitis, another T-cell-mediated autoimmune disease. We discuss possible explanations for this difference.

Amino Acid Sequence↗

Efficacy of vitamin A in reducing preschool child mortality in Nepal.

Community trials of the efficacy of vitamin A supplementation in reducing preschool childhood mortality have produced conflicting results. To resolve the question, a randomised, double-masked, placebo-controlled community trial of 28,630 children aged 6-72 months was carried out in rural Nepal, an area representative of the Gangetic flood plain of South Asia. Randomisation was carried out by administrative ward; the vitamin-A-supplemented children received 60,000 retinol equivalents every 4 months and placebo-treated children received identical capsules containing 300 retinol equivalents. After 12 months, the relative risk of death in the vitamin-A-supplemented compared with the control group was 0.70 (95% confidence interval 0.56-0.88), equivalent to a 30% reduction in mortality. The trial, which had been planned to last 2 years, was discontinued. The reduction in mortality was present in both sexes (relative risk for boys 0.77; for girls 0.65), at all ages (range of relative risks 0.83-0.50), and throughout the year (0.76-0.67). The reduction in mortality risk was not affected by acute nutritional status, as measured by arm circumference. Thus, periodic vitamin A delivery in the community can greatly reduce child mortality in developing countries.

Adult↗

A method for generating antigen-specific rat T helper cell clones.

T lymphocytes play an important role in host responses to microbial antigens, and therefore, in order to facilitate studies to determine the mechanisms involved in the regulation of these responses, a method for the generation of T cell clones with specificity to microbial whole cell (WC) antigens has been developed. T cells were purified from the spleen of rats immunized with WC antigen of either the gram-positive bacterium Streptococcus mutans or the gram-negative bacterium Bacteroides gingivalis and cultured with irradiated Sephadex G-10-passed spleen (feeder) cells and the homologous WC antigen for the generation of T cell clones. Clonal growth of the T cells was maintained for up to 6 months by co-culturing similar numbers of T cells, feeder cells and WC antigen; however, the addition of exogenous interleukin-2 (IL-2) was not required. Phenotypic characterization of the cloned T cells showed that they were CD4+ T helper (Th) cells which did not express the leukocyte-common antigen, but did express receptors for 1L-2. These T cells required the presence of homologous WC antigen for growth and their antigen specificity was further confirmed by the ability of the T cells to proliferate in response to the homologous WC, but not to heterologous microbial WC, antigen. These T cells were further characterized for their ability to produce cytokines, specifically 1L-2 and interferon-gamma, and to provide help for B cell responses to microbial WC antigen. This study describes a reproducible method for the generation of rat Th cell clones with specificity to microbial WC antigens which will be valuable for defining the mechanisms involved in T cell regulation of responses to either gram-positive or gram-negative bacteria.

Animals↗

Determination of pathways of glycogen synthesis and the dilution of the three-carbon pool with [U-13C]glucose.

Rats were infused with glucose at 30 mg/min, containing 18% enriched [U-13C]glucose and [1-14C]- and [3-3H]glucose. The mass isotopomer patterns of 13C-labeled blood glucose and liver glycogen were determined by gas chromatography/mass spectroscopy. The contribution of the direct pathway to glycogen was calculated from the three tracers, and the values by all three were nearly identical, about 50%. The 14C specific activity in carbon 6 of glycogen glucose was about 6% that of carbon 1. The [3H]glucose/[1-14C]glucose ratio in glycogen was 80-90% that in blood glucose. The enrichment of 13C and the specific activity of 14C in glycogen formed by the indirect path were 20-25% of glycogen formed directly from glucose. The dilution is of two kinds: (i) an exchange of labeled carbon with unlabeled carbon in the tricarboxylic acid cycle and (ii) dilution by unlabeled nonglucose carbon. Methods to calculate the two types of dilution are presented. In control rats the dilution factor by exchange in the tricarboxylic acid cycle is 1.4, and the dilution by unlabeled carbon is 2.5- to 3.0-fold, with the overall dilution about 4-fold. In rats preinjected with glucagon, the dilution through the tricarboxylic acid cycle was unaffected but that by nonglucose carbon was decreased.

Animals↗