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Biomedical subjects

A Jones

Publications and source records attributed to A Jones.

At least 523 records · Page 29Linked to original sources
PubMed1989

The influence of Calicophoron microbothrium on the susceptibility of Bulinus tropicus to Schistosoma bovis.

A total of 480 snails were collected from 3 habitats on the Mau Escarpment, Kenya, and were identified as Bulinus tropicus. Of the 351 snails examined alive in London, 75 were infected with Calicophoron microbothrium, 39 with C. microbothrium and Schistosoma bovis, 1 with S. bovis, 24 with other species of trematodes and 212 were uninfected. Examination of digestive glands of B. tropicus either uninfected or infected with both C. microbothrium and S. bovis demonstrated that it is possible to differentiate between parasite and host enzyme activity using glucose phosphate isomerase. However, malate dehydrogenase enables a much clearer differentiation between the enzyme activity of the schistosome and that of the amphistome. Laboratory snail infection experiments demonstrated that it is possible successfully to infect B. tropicus with S. bovis if the snails have previously been exposed to miracidia of C. microbothrium.

Animals↗
PubMed1989

Cognitive bias and irrational belief as predictors of avoidance.

Cognitive bias, i.e. overestimates of subjective probability and cost of catastrophic events, and irrational belief were explored as predictors of avoidance. Three groups-anxiety disordered clients, a mixed group of clinic outpatients, and normals--were administered several self-report inventories. Multiple regression analyses were used to investigate a modified version of the Agoraphobic Cognitions Questionnaire, the Belief Scale, and the Body Sensations Questionnaire as predictors of avoidance, as measured by the Mobility Inventory. It was hypothesized that frequency x probability x cost of catastrophic cognitions (and the occurrence of the events they represent) would be a better predictor of avoidance than frequency alone. It was also hypothesized that irrational thinking would be a significant predictor of avoidance. The results generally supported the hypotheses, with subjective probability emerging as a particularly potent predictor of avoidance. Theoretical and clinical implications are discussed.

Adult↗
PubMed1989

The UK demand for cigarettes 1954-1986, a double-hurdle approach.

The double-hurdle perspective suggests that it is crucial to distinguish between per capita and per smoker consumption when estimating the demand for cigarettes. This paper presents a two equation model which identifies consumption and participation as two separate decisions. The model is estimated with annual data on U.K. cigarette expenditure and participation rates, highlighting the differing influence of prices, income and health scares on the participation rate and on smokers' demand for cigarettes.

Data Collection↗
PubMed1989

Single-dose pharmacokinetics of intravenous ampicillin plus sulbactam in healthy elderly and young adult subjects.

The pharmacokinetics of intravenous ampicillin and sulbactam, a beta-lactamase inhibitor, were evaluated in two different age groups. Twelve healthy elderly subjects (age 65-93 years) and 12 healthy young adult subjects (age 20-35 years) received both a dose of ampicillin 1 g plus sulbactam 0.5 g and a higher dose of ampicillin 2 g plus sulbactam 1 g after a one-week period between doses. A reverse-phase high-pressure liquid chromatography method was used for the quantitation of ampicillin and sulbactam in serum and urine. The pharmacokinetic parameters for both ampicillin and sulbactam were calculated by computer-based two-compartment nonlinear model. After a 30-min infusion, serum concentrations of both drugs declined in a biexponential manner for both doses. Elderly subjects demonstrated significantly lower total clearances (Clt) than young adult subjects of ampicillin 1 g (220.0 +/- 104.2 vs 360.0 +/- 95.8 ml/min/1.73 m2), ampicillin 2 g (72.6 +/- 36.6 vs 306.8 +/- 109.77 ml/min/1.73 m2), sulbactam 0.5 g (122.3 +/- 47.8 vs 263.9 +/- 93.7 ml/min/1.73 m2), and sulbactam 1 g (171.2 +/- 85.8 vs 391.7 +/- 70.8 ml/min/1.73 m2), respectively. Significance was defined as P less than 0.05. Renal clearance was also significantly reduced in the elderly subjects. Area under the curve was found to be significantly increased in the elderly subjects compared to the young subjects for both ampicillin and sulbactam as were the beta elimination half-lives. No significant difference in the apparent volume of distribution, when adjusted for body weight, was found for either sulbactam (P greater than 0.95) or ampicillin (P greater than 0.95) between the two groups. Linear regression analysis revealed that age was significantly correlated with the Clt of ampicillin 1 g (r = 0.85, P less than 0.001), ampicillin 2 g (r = 0.90, P less than 0.001), sulbactam 0.5 g (r = 0.80, P less than 0.001), and sulbactam 1 g (r = 0.93, P less than 0.001). A multivariate analysis showed a slight improvement in correlation when creatinine clearance was added to age and compared with Clt. Urinary recovery of both ampicillin and sulbactam was approximately 60% after 14 h.

Adult↗
PubMed1989

Laboratory based study of undetectable thyroid stimulating hormone.

The clinical importance of an undetectable thyroid stimulating hormone (TSH) concentration (less than 0.2 mU/l) was studied in a consecutive series of 2573 requests for routine thyroid function tests. Two hundred and seventeen (8.4%) patients had an undetectable TSH concentration, and of these 39 (18%) had otherwise normal thyroid hormone concentrations and no history of thyroid disease. In a follow up study 71 patients (34 outpatients and 37 inpatients) with undetectable TSH concentration associated with otherwise normal thyroid hormone concentrations were randomly selected during routine reporting of thyroid function test results. None of these patients had a history of thyroid disease. Sex hormone binding globulin concentrations were increased in five out of 50 of these patients and antithyroid antibodies were detectable in four out of 49, suggesting that in most cases the isolated undetectable TSH concentration was not associated with thyroid dysfunction, particularly hyperthyroidism. Isolated undetectable TSH concentration was observed in both inpatients and outpatients and was not associated with any particular clinical condition. Repeat specimens were received in 54 of the 71 patients and TSH concentration remained persistently undetectable in 35 of these.

Autoantibodies↗
PubMed1989

Correlation of breath sounds with diagnoses of lung dysfunction: experimental observations.

An investigation has been undertaken to determine whether there is any correlation between the spectral analyses of breath sounds at the mouth and the diagnosis of lung dysfunction in a small number of patients. The results of the investigation have shown that it is possible to differentiate between the spectral characteristics of the breath sounds of people who are: (a) normal; (b) asthmatic adult, both before and after the administration of a bronchodilator drug; (c) asthmatic adult, treated with an inhaled steroid, both before and after the administration of a bronchodilator drug; (d) asthmatic child, both before and after the administration of a bronchodilator drug. The possible applications of the technique are discussed.

Adult↗
PubMed1988

Chloroplast transport of a ribulose bisphosphate carboxylase small subunit-5-enolpyruvyl 3-phosphoshikimate synthase chimeric protein requires part of the mature small subunit in addition to the transit peptide.

Ribulose bisphosphate carboxylase small subunit protein is synthesized in the cytoplasm as a precursor and transported into the chloroplast where the amino-terminal portion, the transit peptide, is removed proteolytically. To obtain chloroplast delivery of the 43-kDa 5-enolpyruvyl 3-phosphoshikimate (EPSP) synthase of Salmonella typhimurium, we constructed fusion proteins between the bacterial EPSP synthase and the ribulose bisphosphate carboxylase small subunit. A fusion protein consisting of the transit peptide fused to the EPSP synthase was not transported in vitro or in vivo into chloroplasts. A second fusion protein consisting of the transit peptide and 24 amino acids of the mature small subunit fused to the EPSP synthase was transported both in vitro and in vivo into chloroplasts. It was processed into two polypeptides of 46 and 47 kDa, respectively. This heterogeneity in processing was not caused by the presence of the aroA start codon, since its removal resulted in the same pattern. Substituting 24 different amino acids for the 24 amino acids of the mature small subunit resulted in a fusion protein that was not transported into the chloroplast. It was concluded that a portion of the mature small subunit was needed for efficient chloroplast delivery.

3-Phosphoshikimate 1-Carboxyvinyltransferase↗
PubMed1988

Identification and treatment of risk factors for coronary heart disease in general practice: a possible screening model.

A screening programme for the identification of risk factors for coronary heart disease in all patients aged 25-55 years in a general practice population was studied. The identification of risk factors included measurement of obesity, blood pressure, hypercholesterolaemia, and urinalysis, together with questions about family history, cigarette smoking, alcohol intake, and lifestyle. The patients with identified risk factors were invited to attend a lifestyle intervention clinic organised by the practice nurses and run by the health visitors, with the help of the local authority dietitian. Of 2646 (62%) patients who attended for screening, 78 (64%) of the 121 shown to have a high cholesterol concentration experienced a drop in cholesterol concentration. The mean fall in cholesterol concentration in the 78 patients who showed a positive response to intervention was 1.1 mmol/l. The study was intended as a possible flexible model for screening for coronary heart disease in general practice that could be complemented rather than replaced by opportunistic screening. The issues of organisation, cost, manpower, nonattendance, and effectiveness in a busy general practice environment are discussed.

Adult↗
PubMed1988

Metabolites of procainamide and practolol inhibit complement components C3 and C4.

Drug-induced systemic lupus erythematosus arises from toxic side-effects of administration of hydralazine, isoniazid, procainamide and practolol. Hydralazine and isoniazid are nucleophilic drugs and inhibit the covalent binding reaction of complement components, C3 and C4, an effect likely to lead to deposition of immune complexes (a feature of systemic lupus erythematosus). Procainamide and practolol do not themselves inhibit C3 and C4. A range of metabolites and putative metabolites of procainamide and practolol were synthesized, and tested for their ability to inhibit the covalent binding reactions of C3 and C4. The highly nucleophilic hydroxylamine metabolite of procainamide was strongly inhibitory in both tests, as was a putative hydroxylamine metabolite of practolol. These studies indicate a potential role for the hydroxylamine metabolites in mediating the toxic side-effects of procainamide and practolol, and emphasize the need for adequate measurements of hydroxylamine metabolites in human tissue.

Acecainide↗
PubMed1988

Kubangwa.

Explore the source record for details and available documents.

Adolescent↗
PubMed1988

Interaction of nucleophilic compounds with complement component C4.

Drugs which induce systemic lupus erythematosus as a toxic side effect have been shown to inhibit the covalent binding of C4, which is an important event in immune complex clearance in normal individuals. Human C4 is encoded at two polymorphic loci, C4A and C4B within the Major Histocompatibility Complex and patients with idiopathic SLE are more likely to have a non-functional (null) C4A gene. The C4A and C4B gene products differ in reactivity with C4A being more reactive with nitrogen nucleophiles, including hydralazine and isoniazid (drugs which induce SLE), than with oxygen nucleophiles. We have established an assay system which allows the effect of nucleophiles on C4 in animal sera to be investigated. It has been found that in comparing reactivity of guinea-pig C4 with human C4A and human C4B that guinea-pig C4 is like human C4A and shows greater reactivity towards nitrogen nucleophiles than towards oxygen nucleophiles. This suggests that the guinea-pig should be a good animal model for drug-induced SLE.

Animals↗
PubMed1988

The sonographic features and implications of fetal pleural effusions.

Pleural fluid was detected by ultrasound in three fetuses as an anechoic area surrounding the echogenic fetal lung. In one fetus the underlying lung was small, immobile and of abnormal contour; death occurred in the neonatal period and the lung was found to be hypoplastic. In two other fetuses the lungs appeared sonographically normal, being mobile with normal contours. Both survived, one following spontaneous intra-uterine resolution of the effusion and the other after early neonatal intervention prompted by the antenatal diagnosis. Sonography can detect pleural fluid in utero and may permit differentiation between normal underlying lung and pulmonary hypoplasia. We recommend serial scanning to detect early adverse effects of pleural effusion upon the fetus and to plan management changes.

Adult↗