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Biomedical subjects

D J Wright

Publications and source records attributed to D J Wright.

At least 109 records · Page 6Linked to original sources
PubMed1997

A Change in a Single Midgut Receptor in the Diamondback Moth (Plutella xylostella) Is Only in Part Responsible for Field Resistance to Bacillus thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai.

A population (SERD3) of the diamondback moth (Plutella xylostella L.) with field-evolved resistance to Bacillus thuringiensis subsp. kurstaki HD-1 (Dipel) and B. thuringiensis subsp. aizawai (Florbac) was collected. Laboratory-based selection of two subpopulations of SERD3 with B. thuringiensis subsp. kurstaki (Btk-Sel) or B. thuringiensis subsp. aizawai (Bta-Sel) increased resistance to the selecting agent with little apparent cross-resistance. This result suggested the presence of independent resistance mechanisms. Reversal of resistance to B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai was observed in the unselected SERD3 subpopulation. Binding to midgut brush border membrane vesicles was examined for insecticidal crystal proteins specific to B. thuringiensis subsp. kurstaki (Cry1Ac), B. thuringiensis subsp. aizawai (Cry1Ca), or both (Cry1Aa and Cry1Ab). In the unselected SERD3 subpopulation (ca. 50- and 30-fold resistance to B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai), specific binding of Cry1Aa, Cry1Ac, and Cry1Ca was similar to that for a susceptible population (ROTH), but binding of Cry1Ab was minimal. The Btk-Sel (ca. 600-and 60-fold resistance to B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai) and Bta-Sel (ca. 80-and 300-fold resistance to B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai) subpopulations also showed reduced binding to Cry1Ab. Binding of Cry1Ca was not affected in the Bta-Sel subpopulation. The results suggest that reduced binding of Cry1Ab can partly explain resistance to B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai. However, the binding of Cry1Aa, Cry1Ac, and Cry1Ca and the lack of cross-resistance between the Btk-Sel and Bta-Sel subpopulations also suggest that additional resistance mechanisms are present.

Journal Article↗
PubMed1997

Early bactericidal activity of isoniazid in pulmonary tuberculosis. Optimization of methodology. The DATRI 008 Study Group.

Early bactericidal activity (EBA) of antituberculosis drugs is the rate of decrease in the concentration of tubercle bacilli sputum during the initial days of therapy. The study reported here was designed to optimize the methodology for obtaining precise EBA measurements. The study compared the results with two versus five treatment days; overnight sputum collections with early morning collections; and quantitative smears for acid-fast bacilli (AFB) with quantitative cultures. Isoniazid (INH) was used as a model drug. Among 28 smear-positive patients enrolled in the study in five cities in the United States, 16 were evaluable (INH-susceptible tuberculosis [TB] and adequate sputum collections). The mean baseline bacterial load was 6.69 log10 cfu/ml (SE = 0.24). Quantitative culture of 10- or 12-h sputum collections obtained on two baseline days and treatment Day 5 was the optimal method for EBA measurement. The mean 5-d EBA was 0.21 log10 cfu/ml/d (SE = 0.03; p < 0.001) and the EBA appeared to be constant during the first five treatment days. On the basis of these data, multiarm studies of investigational drugs will require 25 evaluable subjects per arm to detect (80% power and two-tailed alpha of 0.05) an EBA at least 50% as large as the EBA of INH. In countries with a low incidence of TB, the usefulness of this methodology for rapidly assessing new antituberculosis agents may be limited by the relatively large number of subjects required to compare EBA values across treatment arms.

Adult↗
PubMed1997

Self-reported allergy-related symptoms and psychological morbidity in primary care.

OBJECTIVE: To examine the relationship between allergy-related symptoms, food intolerance and psychological distress in primary care. METHODS: Two thousand three hundred and thirty two adults in five General Practices in the South of England completed questionnaires regarding allergy-related symptoms and psychological symptoms, but no association was demonstrated between a history of diagnosed or treated asthma, eczema or hay fever and psychological morbidity. Cases of food intolerance had lower levels of psychological distress than expected compared to hospital samples. Current, but not past wheezing and eczema, was associated with an excess of life stresses in the previous six months. CONCLUSIONS: The association between psychological distress and the label of food allergy/intolerance found in specialist care does not extend to primary care.

Adult↗
PubMed1997

Glycogen: its importance in the infectivity of aged juveniles of Steinernema carpocapsae.

Infective juveniles (IJs) of Steinernema carpocapsae (All) are able to remain relatively highly infective even when they have almost exhausted their neutral lipid reserves. This is not seen in other steinernematid species so we proposed that carbohydrate may be important for infectivity in aging IJs of S. carpocapsae. The present study investigated glycogen utilization in IJs of 4 entomopathogenic nematodes, S. carpocapsae, S. riobravis (Biosys 355), S. feltiae (UK76) and S. glaseri (NC), stored in distilled water at 25 degrees C. The 4 species had appreciable amounts of glycogen; from ca. 8% dry weight in S. riobravis to ca. 18% in S. glaseri. Infective juveniles of S. carpocapsae and S. riobravis survived for 120-135 days and utilized ca. 90% of their glycogen reserve at an almost constant rate during a 112-day storage period. Steinernema feltiae and S. glaseri lived for much longer (> 450 days) and during a 250-day storage period their glycogen content decreased by 27 and 40%, respectively. In contrast to the other 3 species, the rate of lipid decline preceded that of glycogen in S. carpocapsae. The rate of glycogen decline in S. carpocapsae IJs incubated with the glycolytic inhibitor, iodoacetamide (10(-4) M) was significantly reduced (P < 0.05) compared with untreated nematodes, and the infectivity of inhibitor-treated aged (> 80 days) IJs was reduced compared with controls. Incubating aged (80-day) IJs of S. carpocapsae (mean neutral lipid content ca. 10% of initial level) with 10(-4) M iodoacetamide for 24 h significantly reduced (P < 0.05) their infectivity compared with freshly harvested inhibitor-treated IJs and untreated controls. Following an 11-day recovery period, the infectivity of inhibitor-treated aged IJs recovered significantly (P < 0.05). The evidence suggests that glycogen is an important source of energy for maintaining infectivity in aged IJs of S. carpocapsae.

Animals↗
PubMed1996

Effect of induced pyometra on luteal lifespan and uterine fluid concentrations of prostaglandins and interferons in cows.

The objective was to determine whether occurrence of persistent corpora lutea in cows with pyometra could be explained by accumulation of prostaglandins and interferons in the uterus. Pyometra was induced by treatment with hCG, followed by intrauterine infusions of iodine and Actinomyces pyogenes . Five of the seven treated cows developed pyometra as indicated by extended estrous cycles (30-37 + d) and presence of purulent uterine exudate at slaughter (Day 37 after estrus). Mean (+/- standard error) concentrations of prostaglandins E(2) and F(2alpha) for the cows with pyometra were 34.7 +/- 14.4 and 96.3 +/- 28 ng/ml, while the concentrations in uterine flushings in the remaining 2 cows averaged 1.85 +/- 0.7 and 0.9 +/- 0.2 ng/ml, respectively. Based on Western blotting, none of the cows had detectable concentrations of either interferon-alpha or interferon-tau in uterine secretions. In conclusion, pyometra results in increased uterine prostaglandin secretion. While increased secretion of cytokines associated with bacterial infection may be contribute to this effect, there was no evidence in this study to suggest that interferons are involved in the mechanism which causes persistence of the corpus luteum in bovine pyometra.

Journal Article↗
PubMed1996

Eating disturbance and body image: a comparison of a community sample of adult black and white women.

OBJECTIVE: This study examined racial differences in eating disorder symptomatology in a community-based sample of middle-aged adult Black and White women and investigated predictors of body image dissatisfaction in these two different racial groups, since most research has focused on young adult White women. METHOD: Subjects (538 Black and White women) completed the Eating Disorder Inventory and measures of social pressures about thinness and negative attitudes about overweight. RESULTS: Black and White women reported comparable levels of eating disturbance. However, after controlling for degree of overweight, White women had significantly greater rates of body dissatisfaction than Black women. Nonetheless, both racial groups reported considerable body image dissatisfaction and similar factors were found to predict body dissatisfaction for Black and White women. DISCUSSION: Our data and other recent data indicate that eating disturbance occurs across a much broader age, race, and socioeconomic distribution than previously suspected. Research implications are discussed.

Adult↗
PubMed1996

Detection of M. tuberculosis DNA using thermophilic strand displacement amplification.

Strand Displacement Amplification (SDA) is an isothermal, in vitro method of amplifying DNA that is based upon the combined action of a DNA polymerase and restriction enzyme. Previously, a form of SDA was developed which utilizes the exonuclease deficient Klenow fragment of E. coli polymerase I (exo Klenow) and the restriction enzyme HincII to achieve 10(8)-fold amplification in 2 h at 37 degrees C (Walker, G.T., 1993, PCR Methods and Applications 3; 1-6). A new thermophilic form of SDA is reported here which uses a restriction endonuclease from Bacillus stearothermophilus (BsoBI) and a 5'-->3' exonuclease deficient polymerase from Bacillus caldotenax (exo Bca). SDA was used to amplify DNA from Mycobacterium tuberculosis. An amplification factor of 10(10)-fold was achieved after 15 min of SDA at 60 degrees C. The new thermophilic system is much more specific than the previous mesophilic system as evidenced by a dramatic decrease in background amplification products. Thermophilic SDA was also optimized with dUTP substituted for TTP to enable amplicon decontamination using uracil-DNA glycosylase.

Bacillus↗
PubMed1996

Heterogeneity of human intestinal spirochaetes demonstrated by one-dimensional polyacrylamide gel electrophoresis of proteins visualised by (35)S-methionine labelling and Coomassie blue staining.

The relatedness of strains of a human intestinal spirochaete was investigated by comparison of electrophoretic protein profiles produced by Coomassie Blue staining of proteins separated by polyacrylamide gel electrophoresis (PAGE) of lysed organisms and by examination of autoradiographs following PAGE of lysed (35)S-methionine-labelled organisms. A wide diversity of strains was revealed by both techniques but clustering of strains was different by the two methods. These findings support the view that the human intestinal spirochaetes comprise a group of bacteria of considerable heterogeneity.

Autoradiography↗
PubMed1996

Weight modification efforts reported by black and white preadolescent girls: National Heart, Lung, and Blood Institute Growth and Health Study.

OBJECTIVE: This study tested four hypotheses: (1) a high percentage of 9- and 10-year-old girls are already trying to lose weight; (2) more white tha black girls are trying to lose weight; (3) more black than white girls are trying to gain weight; and (4) weight modification efforts of preadolescent girls are influenced by factors other than race, such as maternal criticism, body dissatisfaction, and socioeconomic status. DESIGN: Cross-sectional analysis of baseline data on 2379 girls 9 and 10 years of age, which consisted of 1213 black and 1166 white enrollees. RESULTS: Black girls were taller and heavier and showed earlier signs of puberty than white girls but were less dissatisfied with their weight, body shape, and body parts. Approximately 40% of 9- and 10-year-old girls reported that they were trying to lose weight. Of those girls classified in the fourth quartile of body mass index (BMI), approximately 75% were trying to lose weight. After adjusting for BMI, no significant black and white differences in the prevalence of those trying to lose weight were seen, but significantly more black than white girls were trying to gain weight. Multiple logistic regression identified a high BMI, the mother telling her she was too fat, and body dissatisfaction as the major factors associated with trying to lose weight. However, chronic dieting was only associated with a high BMI and the mother telling her she was too fat. An important predictor of girls who were trying to gain weight was being black, along with having a low BMI and the mother telling her she was too thin. CONCLUSIONS: Attempts at gaining weight are much more frequent among black preadolescent girls than their white counterparts. No racial difference was found between black and white girls in their efforts to lose weight or to practice chronic dieting. Because approximately 40% of 9- and 10-year-old girls are already trying to lose weight, pediatricians should capitalize on this concern by providing information on proper weight control techniques. Educational efforts should be directed to both the mother and the child, because weight control efforts of preadolescent girls are stimulated by their mothers' admonitions of being too fat or too thin. The high prevalence of dieting among the thinnest adolescent girls also needs to be addressed by pediatricians.

Black or African American↗
PubMed1995

Processive post-translational modification. Vitamin K-dependent carboxylation of a peptide substrate.

Mass spectrometry has been used to demonstrate that vitamin K-dependent carboxylation is a processive post-translational modification (i.e. multiple carboxylations occur during a single association between enzyme and substrate). Purified vitamin K-dependent carboxylase can carboxylate as many as 12 glutamate residues in FIXQ/S, a peptide substrate based on amino acids -18 to 41 of the human blood clotting enzyme factor IX. Mass spectrometry was used to determine the number of gamma-carboxyl groups added to FIXQ/S by the carboxylase during an in vitro reaction. Despite the fact that most substrate molecules in a reaction were uncarboxylated, almost all carboxylated FIXQ/S molecules were carboxylated many times. This observation can only be explained by two types of mechanisms. In a processive mechanism, multiple carboxylations could occur during a single substrate binding event. Alternatively, a distributive mechanism could result in the observed behavior if the initial carboxylation event results in a substrate that is additionally carboxylated far more efficiently than the uncarboxylated FIXQ/S. Kinetic experiments and arguments were used to show that the vitamin K-dependent carboxylase is not distributive but rather is one of the first well documented examples of an enzyme that catalyzes a processive post-translation modification.

Amino Acid Sequence↗
PubMed1995

Postinfectious fatigue: prospective cohort study in primary care.

The idea that chronic fatigue has an infectious origin has become popular, but the main evidence for such an association has come from retrospective case-control studies, which are subject to ascertainment bias. We report a prospective study of the outcome of clinically diagnosed infections in patients presenting to UK general practitioners. Questionnaires assessing fatigue and psychiatric morbidity were sent to all patients aged 18-45 years in the study practices. The prevalence of chronic fatigue and chronic fatigue syndrome was then ascertained among 1199 people aged 18-45 who presented to the general practitioners with symptomatic infections and in 1167 people who attended the surgeries for other reasons. 84% were followed up at 6 months. 9.9% of cases and 11.7% of controls reported chronic fatigue (odds ratio 1.0 [95% CI 0.6-1.1]). There were no differences in the proportions who met various criteria for chronic fatigue syndrome. No effect of infection was noted when we excluded subjects who reported fatigue or psychological morbidity at the baseline screening. The strongest independent predictors of postinfectious fatigue were fatigue assessed before presentation with clinical infection (3.0 [1.9-4.7]) and psychological distress before presentation (1.8 [1.2-2.9]) and at presentation with the acute infection (1.8 [1.1-2.8]). There was no effect of sex or social class. Our study shows no evidence that common infective episodes in primary care are related to the onset of chronic fatigue or chronic fatigue syndrome.

Adolescent↗
PubMed1995

Intraoperative determination of intestinal viability by pulse oximetry.

The utility of transserosal photoplethysmographic pulse oximetry (PO) to assess intestinal viability intraoperatively was evaluated using an experimental canine model. Comparisons of PO were made with continuous-wave Doppler ultrasound (CWDU) and fluorescein (FL) using histopathologic examination for control. Clinical examination estimates were included for reference. Four 20 cm portions of small bowel from each of four dogs were made ischemic by mesenteric ligation. Thus 320 individual 1 cm bowel segments were studied by means of PO, CWDU, FL, and control histologic grading for ischemia. Statistical analysis revealed no significant differences, with PO matching CWDU and FL in intraoperative assessment of small bowel viability. PO, which is readily available in most operating rooms, is a simpler method than CWDU or FL for assessing intestinal viability. This technique is operator independent, easy to interpret and repeat, and is well tolerated. PO is the preferred alternative for objective intraoperative assessment of intestinal viability.

Animals↗
PubMed1995

Post-hepatitis syndrome revisited.

To examine the role of acute hepatitis A and B infection in the aetiology of chronic fatigue syndrome and psychiatric morbidity we studied 40 patients with acute viral hepatitis A or B consecutively admitted to an infectious diseases unit and studied at least 6 months after recovery. Liver function tests (LFT) had returned to normal in each case. Forty-seven patients with other infectious diseases, of which 12 were presumed viral, admitted immediately after each hepatitis patient during the same period acted as controls. The main outcome measures were scores on a fatigue and muscle pain questionnaire, general health questionnaire (GHQ-12) and supplementary questions. The hepatitis cases scored significantly higher fatigue scores, GHQ-12 scores and muscle pain scores. Length of time since recovery from illness, age and sex were not confounding factors. Hepatitis cases were also less energetic, had greater weight change, had altered alcohol tolerance, had less exercise tolerance and felt less fit than the control group and compared with their premorbid state. Hence fatigue is more common after recovery in patients hospitalized for hepatitis A and B up to 30 months post-infection compared with matched controls hospitalized for other infectious diseases. Hepatitis A and B infection is a risk factor for post-infection fatigue, intermittent fatigue, as well as for psychiatric morbidity.

Adolescent↗
PubMed1995

Technical note: digital radiographic pelvimetry--a novel, low dose, accurate technique.

A technique is described for lateral pelvimetry which results in a lower radiation dose than that resulting from conventional film-screen pelvimetry and computed tomography (CT) pelvimetry. It uses digital radiographic imaging thereby closely matching conventional techniques yet additionally providing post-processing facilities including distance measurement and contrast adjustment. The digital technique was evaluated with an anthropomorphic phantom and compared with the conventional technique by measuring entrance surface doses on two groups of post-natal patients. Digital radiography gave radiation doses 10 times lower than those using conventional techniques.

Female↗
PubMed1994

Population based study of fatigue and psychological distress.

OBJECTIVES: To determine the prevalence of fatigue in the general population and the factors associated with fatigue. DESIGN: Postal survey. SETTING: Six general practices in southern England. SUBJECTS: 31,651 men and women aged 18-45 years registered with the practices. MAIN OUTCOME MEASURES: Responses to the 12 item general health questionnaire and a fatigue questionnaire which included self reported measures of duration, severity, and causes of fatigue. RESULTS: 15,283 valid questionnaires were returned, giving a response rate of 48.3%, (64% after adjustment for inaccuracies in the practice registers). 2798 (18.3%) of respondents reported substantial fatigue lasting six months or longer. Fatigue and psychological morbidity were moderately correlated (r = 0.62). Women were more likely to complain of fatigue than men, even after adjustment for psychological distress. The commonest cited reasons for fatigue were psychosocial (40% of patients). Of 2798 patients with excessive tiredness, only 38 (1.4%) attributed this to the chronic fatigue syndrome. CONCLUSION: Fatigue is distributed as a continuous variable in the community and is closely associated with psychological morbidity.

Adolescent↗