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Biomedical subjects

J Yeo

Publications and source records attributed to J Yeo.

At least 19 recordsLinked to original sources

Thermodynamic glass transition in finite dimensions.

Using an effective potential method, a replica formulism is set up for describing supercooled liquids near their glass transition. The resulting potential is equivalent to that for an Ising spin glass in a magnetic field. Results taken from the droplet picture of spin glasses are then used to provide an explanation of the main features of fragile glasses.

Journal Article↗

Co-morbidity in older patients with COPD--its impact on health service utilisation and quality of life, a community study.

BACKGROUND: co-morbidity has been shown to be an important consideration in COPD with an estimated prevalence of 84%. In the Netherlands, a weak association between health-related quality of life and lung function has been found, with a closer link to co-morbidity. OBJECTIVE: to determine the influence of co-morbidity on quality of life and health service utilisation in older patients with COPD in the community. DESIGN: observational cohort study. SETTING: general practice in the North East of England that has a list size of 8300. PARTICIPANTS: 27 patients aged 70 years or above on the practice COPD register. MEASUREMENTS: data on age and sex, spirometry to confirm the diagnosis of COPD, questionnaires to assess quality of life, activities of daily living (ADLs) and co-morbidity. Health service utilisation was recorded by the number of primary and secondary care attendances in the previous year. RESULTS: 10 had mild, 12 had moderate, and 5 had severe disease. Mean age was 76 years. Quality of life (QOL), co-morbidity and health service utilisation measurements were not significantly different between COPD severity groups. There was a significant positive correlation between increasing co-morbidity and poor QOL (r = 0.45, P < 0.05), and significant negative correlation between co-morbidity and ADL scores (scored inversely), r = -0.54, P < 0.05. Significant negative correlation was found between co-morbidity and primary care attendances (r = -0.41, P < 0.05) and significant positive correlation between worsening QOL and secondary care attendances (r = 0.46, P < 0.05). CONCLUSIONS: co-morbidity has an important part to play in COPD assessment, more accurately reflecting QOL in our population. Health service utilisation did not correlate to forced expiratory volume (FEV1)-defined COPD severity.

Aged↗

Complexity of vector spin glasses.

We study the annealed complexity of the m-vector spin glasses in the Sherrington-Kirkpatrick limit. The eigenvalue spectrum of the Hessian matrix of the Thouless-Anderson-Palmer free energy is found to consist of a continuous band of positive eigenvalues in addition to an isolated eigenvalue and (m-1) null eigenvalues due to rotational invariance. Rather surprisingly, the band does not extend to zero at any finite temperature. The isolated eigenvalue becomes zero in the thermodynamic limit, as in the Ising case (m=1), indicating that the same supersymmetry breaking recently found in Ising spin glasses occurs in vector spin glasses.

Journal Article↗

Fluorescence polarization assay for the diagnosis of bovine brucellosis: adaptation to field use.

A fluorescence polarization assay (FPA) was used to test whole blood samples prepared by mixing blood cells from cattle without exposure to Brucella abortus (B. abortus) with sera from animals with confirmed (bacteriologically) infection. A cut-off value between negative and positive values was initially established to be 87.2mP. This value was changed to 95mP to increase assay specificity without loss of sensitivity when testing blood samples from negative animals. The FPA technology was applied to whole blood samples in the field and to stored whole blood samples using two diluent buffers. Relative sensitivity and specificity values for the FPA performed in the field, based on buffered antigen plate agglutination test and competitive enzyme immunoassay results were 95.3 and 97.3%, respectively. However, to obtain maximum sensitivity and specificity, a cut-off value of 105mP was determined for fresh whole blood samples. The relative sensitivity and specificity values of the FPA when testing stored whole blood samples were 100% each using a 95mP cut-off.The usefulness of the FPA for testing whole blood samples in the field was demonstrated.

Agglutination Tests↗

Nitric oxide synthase and glutamate receptor immunoreactivity in the rat spinal trigeminal neurons expressing Fos protein after formalin injection.

Although recent studies implicated glutamate receptors and nitric oxide in nociception, much still needs to be known about their localisation in neurons involved in nociceptive transmission from the orofacial region. In this study, c-fos expression indicated by Fos immunohistochemistry in the caudal spinal trigeminal nucleus induced by subcutaneous injection of formalin into the lateral face of the rat was used as a marker for nociceptive neurons. The study sought to determine whether Fos-positive neurons express nitric oxide synthase, glutamate N-methyl-D-aspartate type receptor subunit 1, and glutamate alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid type receptor subunit 2/3; and whether they project to the thalamus. After formalin injection, many Fos-positive nuclei appeared in the superficial laminae of the ipsilateral trigeminal nucleus. Confocal laser scanning microscope revealed that almost all neurons with Fos immunofluorescent nuclei were colocalised with N-methyl-D-aspartate receptor 1, 94% with glutamate receptor 2/3 and 14% with nitric oxide synthase. Some of them were closely related to neurons labelled by nitric oxide synthase. Lastly, some of the Fos-positive neurons were labelled by tetramethylrhodamine-dextran injected into the trigeminothalamic tract or the thalamic region. The results suggested that activation of N-methyl-D-aspartate receptor 1 and glutamate receptor 2/3 upon glutamate release in response to noxious stimulation to the orofacial region might mediate c-fos expression in neurons involved in nociception. The expression of Fos in the neurons could also be mediated by nitric oxide produced from the same, as well as neighbouring neurons, when nociceptive stimulation persisted. Fos-positive neurons in the spinal trigeminal nucleus may project to the thalamus, relaying orofacial nociception to the higher sensory centre.

Animals↗

Safety profile and tolerability of amprenavir in the treatment of adult and pediatric patients with HIV infection.

BACKGROUND: Amprenavir (APV) is a new HIV-I protease inhibitor used in combination with other antiretroviral agents for the treatment of HIV-1 infection. OBJECTIVE: The aim of this study was to assess the safety profile and tolerability of APV. METHODS: A review of data from 358 adults enrolled in 2 phase III, randomized, 48-week, controlled studies and from 268 children enrolled in 1 phase II and 1 phase III study was conducted. The adult data were collected between February 25, 1997, and April 1, 1999. Data were collected in children from September 10, 1997, to January 15, 1999; these data were collected before completion of either study. Adults and children who had and had not been treated previously with antiretroviral agents were enrolled. In these studies, APV was used in combination with 2 nucleoside reverse transcriptase inhibitors. RESULTS: The most common drug-related adverse events in patients receiving APV were gastrointestinal events and oral/perioral paresthesia. The majority of adverse events were mild or moderate in intensity, early in onset, and transient. Nausea (27/358 patients, 8%), vomiting (15/358, 4%), rash (11/358, 3%), and diarrhea/loose stools (9/358, 3%) were the most common adverse events associated with treatment discontinuation. Severe laboratory abnormalities possibly related to APV were rare. In children, the nature and frequency of adverse events were similar to those in adults. Metabolic complications were infrequent in APV studies to date; symptoms related to fat redistribution were reported in <3% of patients treated with APV. Lipid or glucose laboratory abnormalities were reported with similar frequency in the APV and control groups in both studies in adults. CONCLUSIONS: In the clinical trials reviewed, APV was generally well tolerated when administered with other antiretroviral agents in adult and pediatric patients with HIV infection.

Adolescent↗

Amprenavir in combination with lamivudine and zidovudine versus lamivudine and zidovudine alone in HIV-1-infected antiretroviral-naive adults. Amprenavir PROAB3001 International Study Team.

OBJECTIVES: To compare the antiviral activity and safety of a new protease inhibitor, amprenavir (141W94) in combination with lamivudine and zidovudine, versus lamivudine and zidovudine alone in HIV-1 infected, antiretroviral-naive subjects. DESIGN: Subjects (n=232) with a CD4 T cell count of > or =200 cells/mm3, plasma HIV-1 RNA levels of > or =10000 copies/ml, and < or =4 weeks of prior nucleoside antiretroviral therapy, were stratified according to baseline plasma HIV-1 RNA level (10000-30000; 30000-100000; or >100000 copies/ml). Subjects received double-blind treatment with either 1200 mg amprenavir twice daily in combination with lamivudine (150 mg twice daily) and zidovudine (300 mg twice daily) (amprenavir/lamivudine/zidovudine) or matched placebo, lamivudine and zidovudine for 16 weeks. Thereafter, subjects with confirmed plasma HIV-1 RNA levels of > or =400 copies/ml could add open-label amprenavir or switch to other antiretrovirals and continue treatment for up to a minimum of 48 weeks. The primary endpoint of the study was defined as the proportion of subjects with plasma HIV-1 RNA of <400 copies/ml at 48 weeks. RESULTS: At 48 weeks, a significantly greater proportion of amprenavir/lamivudine/zidovudine subjects had plasma HIV-1 RNA levels <400 copies/ml than lamivudine/ zidovudine subjects in the overall population: 41 versus 3% (intent-to-treat missing equals failure analysis) (P<0.001); 93 versus 42% (as-treated analysis) (P<0.001); and within each of the three randomization strata (P<0.001). Subjects on amprenavir/lamivudine/zidovudine experienced longer time to event (permanent discontinuation of randomized therapy or viral rebound) than those on lamivudine/zidovudine (median of 33 versus 13 weeks; P<0.001). A significantly greater incidence of drug-related nausea, vomiting, rash and oral/perioral paresthesia was observed with amprenavir/lamivudine/zidovudine than with lamivudine/zidovudine. CONCLUSIONS: Amprenavir, in combination with lamivudine and zidovudine, has potent and durable antiviral activity in antiretroviral-naive subjects over 48 weeks. Amprenavir was safe and generally well tolerated.

Adolescent↗

Measurement of total phospholipids in urine of patients treated with gentamicin.

AIMS: The excretion of phospholipids in urine may be a marker of the early renal toxicity of the aminoglycoside antibiotics. Urinary phospholipids are formed in myeloid bodies which develop in the lysosomes of proximal tubules during treatment with the aminoglycosides, and overflow into the urine. METHODS: Published assays were modified in order to measure the total phospholipid concentrations in human urine. Phospholipids were extracted from freeze-dried urine samples, digested in concentrated sulphuric acid, and the inorganic phosphorus content determined by complexing with ammonium molybdate and measuring the absorbance at 820 nm. Ten septicaemic patients treated with gentamicin for 5-7 days had significantly higher urine phospholipid concentrations than 10 healthy untreated control subjects (P < 0.0001). There was a negative linear relationship between phospholipid excretion and creatinine clearance (r2 = 0.71). RESULTS: In 34 patients with acute pyelonephritis, increased phospholipid concentrations were observed prior to treatment compared with healthy controls (P < 0.001) and did not alter during treatment with gentamicin. However, the phospholipid concentrations decreased significantly after treatment was completed (P < 0.03). CONCLUSIONS: These studies suggest that urinary phospholipids may indicate early aminoglycoside toxicity but with poor specificity, as many of the infections being treated may themselves be associated with phospholipiduria.

Adolescent↗

Effect of feeding diets containing an antibiotic, a probiotic, or yucca extract on growth and intestinal urease activity in broiler chicks.

A 6-wk study was conducted to determine the effect of feeding diets containing an antibiotic, a probiotic, or yucca extract on daily gain, feed conversion ratio, and urease activity and ammonia production in intestinal contents of broiler chicks. Four replicates of 10 broiler chicks (average body weight, 48 g) each were assigned to a control or diets containing 0.1% chloroxytetracycline (antibiotic), 0.1% Lactobacillus casei (probiotic), or 0.2% yucca extract. Feeding a diet containing the probiotic significantly (P < 0.05) increased average daily gain during the first 3-wk period compared to the control (30.7 vs 28.7 g). This increase was partly accounted for by increased feed intake. During the first 3 wk, feeding the diet containing probiotic significantly (P < 0.05) decreased urease activity (per gram of collected contents) in small intestinal contents but not in large intestinal contents, compared with the control. Urease activity determined at 6 wk of age was not significantly affected by diet. Our studies indicate that dietary probiotic decreases urease activity in the small intestinal contents of young chicks and thus may be beneficial for improving animal health and growth, especially during early life.

Ammonia↗

Bone marrow scintigraphy using technetium-99m-antigranulocyte antibody in hematologic disorders.

UNLABELLED: Bone marrow is the primary site for many hematologic disorders. To date, however, no suitable bone marrow imaging method has been found. The present study investigates the usefulness of bone marrow immunoscintigraphy using 99mTc-labeled antigranulocyte antibody (anti-NCA-95) in 31 patients with hematologic disorders. METHODS: One milligram of antibody labeled with 259-370 MBq 99mTc was injected intravenously, and bone marrow images were taken 4 hr later. We also calculated the uptake ratios of lumbar bone marrow-to-background (L/B) and ilium-to-background (I/B). RESULTS: Of 15 patients with aplastic anemia, 7 showed diffusely decreased antibody uptake (L/B = 2.3 +/- 0.8, I/B = 3.0 +/- 0.8) compared to control patients (n = 21, L/B = 8.2 +/- 2.5, I/B = 10.3 +/- 3.1) Six patients had both decreased and increased uptake areas and two had normal to slightly increased uptake. Of those patients receiving various types of therapy for aplastic anemia, all but one showed increased or irregular uptake. The degree of antibody uptake in the bone marrow correlated with peripheral blood analyses (hemoglobin, white blood cells, platelets). Of six patients with myelodysplastic syndrome, four had irregular uptake and two diffusely decreased uptake. Four patients with myelogenous leukemia showed normal uptake, whereas two with lymphocytic leukemia had decreased uptake. Patients with iron deficiency anemia, pure red cell aplasia or thalassemia minor exhibited normal uptake with bone marrow expansion. CONCLUSION: Immunoscintigraphy with antigranulocyte antibody is a useful method for evaluating the bone marrow status of patients with various hematologic disorders.

Adolescent↗

Indicator organism sources and coastal water quality: a catchment study on the island of Jersey.

Compliance monitoring of bathing waters at La Grève de Lecq on the North coast of Jersey revealed a significant deterioration in water quality between 1992 and 1993, as indexed by presumptive coliform, presumptive Escherichia coli and streptococci concentrations. During the 1993 bathing season the beach failed to attain the compliance with the EC Guideline criteria for presumptive E. coli and streptococci. A bacteriological survey of the stream catchment draining to the beach revealed that: (i) concentrations of faecal indicator organisms were enhanced at high discharge after rainfall; and (ii) a captive water fowl population, which expanded between 1990 and 1993, was a potential source of faecal pollution. Strategies for catchment management are discussed.

Analysis of Variance↗

Cigarette smoking and the outcomes of in vitro fertilization: measurement of effect size and levels of action.

OBJECTIVE: To assess whether cigarette smoking in women or men affects the outcomes of IVF-ET and at what functional levels smoking is active. INTERVENTIONS: Demographic and smoking data were collected by questionnaire at the onset of consecutive treatment cycles (n = 462) and at the time of ET. In addition to routine endocrine and clinical data, circulating immunoreactive inhibin, follicular fluid E2 endometrial thickness, and morphology were assessed. Reported exposure to cigarettes was validated using a serum cotinine assay. RESULTS: Serum cotinine level at the onset of treatment correlated strongly with the number of cigarettes reported (r = 0.68). The duration and dose of gonadotropin treatment was greater among active smokers than never smokers: 10.2 versus 9.2 days and 24.7 versus 19.8 ampules, respectively. Fertilization, pregnancy, and abortion rates were similar between groups. Multivariate analyses demonstrated negative correlation between female age, but no such effect was seen with female or male smoking. Sperm concentration was significantly reduced in male smokers (prewash: 108 versus 130 x 10(6); postwash: 17.1 versus 21.6 x 10(6)), although fertilization rate was unaffected (66% versus 62%). Follicular function, assessed using serum inhibin and E2, as well as follicular fluid E2 levels showed no significant difference between active smokers and never smokers. Endometrial thickness and morphology also were similar between groups. CONCLUSIONS: These data suggest that among couples undergoing IVF neither female nor male smoking has a measurable deleterious effect on conception rate. Female age remains a far more potent prognostic factor in the current study. However, when all the published data are combined, a significant deleterious effect of smoking on conception is suggested, with a common odds ratio of 0.540 (95% confidence interval 0.385 to 0.757).

Adult↗