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Biomedical subjects

W G Johnson

Publications and source records attributed to W G Johnson.

At least 127 records · Page 7Linked to original sources
PubMed1972

Vibrio parahaemolyticus gastroenteritis in Maryland: laboratory aspects.

Vibrio parahaemolyticus was the etiological agent in three food-related epidemics of gastroenteritis in Maryland, during August 1971. These outbreaks involved crab food products. Fifteen isolates of V. parahaemolyticus were made which included 11 from patients and 4 from foods. Serotype 04:K11 was the cause of the outbreaks. It was recovered from patients in each outbreak and gave a positive Kanagawa reaction, an indication of enteropathogenicity. Other patient isolates included types 03:K30, 03:K33, and an untypable isolate, all of which were Kanagawa negative. Food isolates included serotypes 03:K30, 02:K28, and two untypable isolates, all of which were Kanagawa negative. The outbreaks reported in this paper constitute the first confirmed foodborne epidemics due to V. parahaemolyticus in the United States. Methods for the isolation and identification of V. parahaemolyticus are presented, including a procedure for the simple conversion of conventional laboratory media into suitable culture media for this halophilic organism.

Bacteriological Techniques↗
PubMed1972

The metabolism of Tay-Sachs ganglioside: catabolic studies with lysosomal enzymes from normal and Tay-Sachs brain tissue.

The catabolism of Tay-Sachs ganglioside, N-acetylgalactosaminyl- (N-acetylneuraminosyl) -galactosylglucosylceramide, has been studied in lysosomal preparations from normal human brain and brain obtained at biopsy from Tay-Sachs patients. Utilizing Tay-Sachs ganglioside labeled with (14)C in the N-acetylgalactosaminyl portion or (3)H in the N-acetylneuraminosyl portion, the catabolism of Tay-Sachs ganglioside may be initiated by either the removal of the molecule of N-acetylgalactosamine or N-acetylneuraminic acid. The activity of the N-acetylgalactosamine-cleaving enzyme (hexosaminidase) is drastically diminished in such preparations from Tay-Sachs brain whereas the activity of the N-acetylneuraminic acid-cleaving enzyme (neuraminidase) is at a normal level. Total hexosaminidase activity as measured with an artificial fluorogenic substrate is increased in tissues obtained from patients with the B variant form of Tay-Sachs disease and it is virtually absent in the O-variant patients. The addition of purified neuraminidase and various purified hexosaminidases exerted only a minimal synergistic effect on the hydrolysis of Tay-Sachs ganglioside in the lysosomal preparations from the control or patient with the O variant of Tay-Sachs disease.

Adult↗
PubMedDate not supplied

Lipid storage myopathy, ichthyosis, and steatorrhea.

A 41-year-old man had ichtyrosis, ectropion, steatorrhea, and slowly progressive proximal limb weakness. Biopsies showed abnormal lipid accumulation in muscle, liver skin, leukocytes, and gastric mucosa. Lipid storage was particularly marked in cultures of skin and muscle, and it increased in subsequent cell generations. By electron microscopy, the lipid globules showed no limiting membranes. The stored lipid was identified by thin-layer chromatography as triglyceride; there was no excess of cholesterol or cholesteryl esters. Muscle carnitine concentration and activities of carnitine palmityltransferase and acid lipase were normal; 14CO2 production from labeled palmitate in leukocytes was not impaired. The excessive accumulation of triglyceride in different tissues and in the progeny of cells in tissue culture suggests a genetic error of lipid metabolism.

Adult↗
PubMedDate not supplied

Psychopathology correlates of binge eating and binge eating disorder.

The present study examined the psychopathology associated with binge eating disorder (BED), a new diagnostic category proposed for DSM-IV to classify patients with significant binge eating problems in the absence of purging. Self-report measures of psychopathology (e.g., depression, anxiety) and body image disturbance were administered to 72 women who prospectively (1) met criteria for BED (DSM-IV criteria), (2) reported frequent bingeing but did not meet BED criteria, and (3) denied problems with eating. Subjects satisfying BED criteria reported higher levels of psychopathology than normals on all measures and subclinical binge eaters scored between these two groups, but they were closer to subjects without eating problems. The pattern of results was essentially unchanged when corrected for weight. BED subjects and subclinical binge eaters were less satisfied with their bodies than were normal controls. These findings suggest that BED is not only characterized by frequent bingeing, but more importantly is associated with elevated psychopathology. Overall, these results lend support to the diagnostic criteria proposed for BED.

Adult↗
PubMedDate not supplied

What is binge eating? A comparison of binge eater, peer, and professional judgments of eating episodes.

Binge eating is a central diagnostic feature of bulimia nervosa (BN) and binge-eating disorder (BED), yet the phenomenon of bingeing has not been adequately defined, and there is considerable variability in how individuals label eating episodes as binges. We examined the agreement among binge-eating individuals, non-eating-disordered peers, and professional dietitians over whether particular eating episodes were binges. Twenty-nine females with BED, fifteen nonclinical binge eaters (NCB), three peer judges, and three dietitians rated a sample of eating episodes of the binge-eating individuals as either binges or nonbinges based on the types and amounts of food eaten as well as the duration of each eating episode. BED participants labeled a significantly higher proportion of their intakes as binges relative to NCB participants. Peer judges were more likely than were dietitians to label participants' eating episodes as binges. Agreement within dietitian and peer groups was poor to fair, whereas agreement between these groups was fair. Finally, agreement between participants and the external judges (i.e., peers, dietitians) was poor. Possible explanations for these findings as well as implications for the diagnosis of BN and BED are discussed.

Adult↗
PubMedDate not supplied

Cost-effectiveness studies of medical and chiropractic care for occupational low back pain. a critical review of the literature.

BACKGROUND CONTEXT: Back pain is the single most costly work-related injury. Chiropractors and physicians are the main primary care providers for occupational low back pain (OLBP), but there is no consensus regarding the relative cost-effectiveness of these two modes of care. PURPOSE: To critically appraise and synthesize recent literature on the cost-effectiveness of medical and chiropractic care for OLBP, and to propose a cost-effectiveness methodology that integrates epidemiologic and economic methods for future studies. STUDY DESIGN: Literature review. MEDLINE was searched from 1990 through 1999. Nine articles that met the inclusion criteria were reviewed. The methodological quality of the articles was critically appraised independently by two epidemiologists using standardized review criteria. Two health economists reviewed the studies on cost-effectiveness. RESULTS: The current literature suggests that chiropractors and physicians provide equally effective care for OLBP but that chiropractic patients are more satisfied with their care. Evidence on the relative costs of medical and chiropractic care is conflicting. Several methodological deficiencies limit the validity of the reviewed studies. No studies combine high-quality cost data with adequate sample sizes and controls for confounding factors. CONCLUSION: Existing studies fail to clarify whether medical or chiropractic care is more cost effective. We suggest that future studies must combine epidemiologic and economic methods to answer the question adequately.

Chiropractic↗
PubMedDate not supplied

Macronutrient intake, eating habits, and exercise as moderators of menstrual distress in healthy women.

The present investigation studied the relationship between symptoms of menstrual distress and macronutrient intake, eating behavior, and exercise in healthy women. Twenty-six normally menstruating women with no complaints of menstrual distress completed a disguised questionnaire on menstrual symptoms and monitored the type and amount of food consumed as well as the type and duration of exercise during a full menstrual cycle. Menstrual cycle phases were determined by the presence of menses, ovarian hormonal assays, and basal temperature monitoring. Reports of pain, water retention, negative affect, behavior change, and arousal were significantly higher (p < .05 or better) in the perimenstruum when compared to the follicular and luteal phases. During the perimenstruum, a higher energy intake of carbohydrate was associated with higher ratings of negative affect (p < .01) and impaired performance/decreased activity (p < .05). Lower energy intake of protein was associated with higher ratings of well being (p < .05). Overeating and dieting behavior were related to greater water retention (p < .01), autonomic reactions (p < .05), and appetite (p < .05). The amount of aerobic exercise in contrast to the intensity was related to lower water retention (p < .01), autonomic reactions (p < .05), and appetite (p < .01). Carbohydrate consumption, eating behavior, and regular exercise are reliably associated with menstrual distress and deserving of experimental evaluation as treatment interventions for menstrual distress.

Adolescent↗
PubMedDate not supplied

The effect of five forage species on transport and transformation of atrazine and isoxaflutole (balance) in lysimeter leachate.

A field lysimeter study with bare ground and five different ground covers was established to evaluate the effect of forage grasses on the fate and transport of two herbicides in leachate. The herbicides were atrazine (ATR; 2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) and isoxaflutole [IXF; 5-cyclopropyl-4-(2-methylsulfonyl-4-trifluormethyl-benzoyl)isoxazole], which has the commercial name Balance (Aventis Crop Science, Strasbourg, France). The ground covers included orchardgrass (Dactylis glomerata L.), smooth bromegrass (Bromus inermis Leyss.), tall fescue (Festuca arundinacea Schreb.), timothy (Phleum pratense L.), and switchgrass (Panicum virgatum L.). The results suggested that the total IXF (parent + metabolites) showed higher mobility than ATR and its metabolites. Differences in the timing of transport reflected the rapid degradation of IXF to the more soluble, stable, and biologically active diketonitrile (DKN) metabolite in the system. Although grass treatments did not promote the hydrolysis of DKN, they significantly reduced its transport in the leachate through enhanced evapotranspiration. Grass treatments significantly enhanced ATR degradation in the leachates and soils, especially through N dealkylation, but they did not reduce total ATR transported in the leachate. Leachate from the orchardgrass lysimeters contained the highest proportion of ATR metabolites (64.2%). Timothy and smooth bromegrass treatments also displayed a significant increase in ATR metabolites in leachate. Grass-treated lysimeters showed higher microbial biomass carbon than bare ground. For ATR treatments, the proportion of metabolites in the leachate strongly correlated with the elevated soil microbial biomass carbon in forage treatments. In contrast, DKN degradation was poorly correlated with soil microbial biomass carbon, suggesting that DKN degradation is an abiotic process.

Atrazine↗