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Biomedical subjects

R Taylor

Publications and source records attributed to R Taylor.

At least 541 records · Page 30Linked to original sources
PubMed1986

In vivo human tracheal pressure-area curves using computerized tomographic scans. Correlation with maximal expiratory flow rates.

In order to develop a simple technique to measure in vivo pressure-area (P-A) curves of the extrathoracic trachea in humans, we studied 14 normal male subjects. Valsalva and Mueller maneuvers were performed at FRC, and tracheal cross-sectional area (TXSA) was measured using computed tomography. Extrathoracic tracheal transmural pressure (TMP) was obtained as airway opening minus atmospheric pressure (Pat). Tracheal "compliance" (TC) was measured on the "inflation" limb of the P-A curve. Tracheal compliance was not a significant predictor of maximal expiratory flow rates, and TXSA at zero TMP was a significant predictor of peak expiratory flow rate but not of FEV1 or Vmax50. P-A curves showed an unexpected configuration characterized by a plateau or an increase in TXSA with TMP lower than -15 cm H2O. P-A curves obtained in 5 subjects using extrathoracic esophageal pressure as tracheal external pressure instead of atmospheric pressure did not show a plateau or an increase in TXSA with Mueller maneuvers. In these 5 subjects, TC using esophageal pressure rather than Pat did not aid in the prediction of flow. We conclude that extrathoracic tracheal external pressure is not Pat because this pressure is probably affected by transmission of pleural pressure to the cervical interstitial tissue as well as by the contraction of cervical accessory inspiratory muscles. Therefore, true tracheal compliance cannot be simply measured since it requires placement of an esophageal balloon.

Adult↗
PubMed1986

Maximum flow ratios at mid-vital capacity in young healthy adults.

Upper airway obstruction is usually diagnosed by visual examination of maximum expiratory and inspiratory flow-volume curves and by calculating a ratio of expiratory to inspiratory flow at 50 percent of vital capacity (mid-vital capacity flow ratio); however, reference values of this ratio have not been well established, and considerable variability exists. The purpose of this study was to examine the range of mid-vital capacity flow ratios in a group of healthy subjects and to determine if some of the variability is accounted for by different maximum inspiratory pressures. We measured maximum expiratory and inspiratory flows at 50 percent of vital capacity from the flow-volume curves, and maximum inspiratory pressures in a group of 60 healthy nonsmokers (30 men and 30 women) whose ages ranged from 21 to 40 years. We found that mid-vital capacity flow ratio (mean +/- SD) was 0.72 +/- 0.19 in men and 0.77 +/- 0.18 in women. The coefficient of variation of the mid-vital capacity flow ratio was 28 percent for men and 23 percent for women. The 95 percent confidence limits for the mid-vital capacity flow ratio were 0.65 to 0.79 for men and 0.70 to 0.84 for women. Maximum inspiratory pressures (mean +/- SD) were 129 +/- 30 cm H2O in men and 91 +/- 16 cm H2O in women, not significantly different from previous studies. Normalizing maximum inspiratory flow for maximum inspiratory pressure did not reduce the coefficient of variation, which became 29 percent in men and 30 percent in women. We conclude that the range of mid-vital capacity flow ratios is wide, and it cannot be reduced by standardizing it for maximum inspiratory pressures.

Adult↗
PubMed1986

Class III alleles and high-risk MHC haplotypes in type I diabetes mellitus, Graves' disease and Hashimoto's thyroiditis.

By typing a large quantity of family-based material for HLA-B, HLA-DR, C4, C2 and factor B, we were able to derive four-gene complement haplotypes (C4A, C4B, C2, BF) and six-gene MHC haplotypes (HLA-B, complement, HLA-DR). Fourteen six-gene MHC haplotypes showed linkage disequilibrium but exact frequencies could not be determined because it was not always possible to assign null C4 alleles in families where null genes were not clearly seen to segregate. Comparison of unrelated type I diabetes, Graves' disease and Hashimoto's thyroiditis patients with healthy unrelated controls revealed the following MHC allele associations: C4B*3, HLA-DR3 and HLA-DR4 with type I diabetes; BF*F1 and HLA-DR3 with Graves' disease; HLA-DR4 with Hashimoto's thyroiditis. By typing families of type I diabetes and Graves' disease patients we were able to derive two high-risk DR3+ MHC haplotypes for both type I diabetes and Graves' disease. These are HLA-B8 C4A*Q0 C4B*1 BF*S HLA-DR3 and HLA-B18 C4A*3 C4B*Q0 BF*F1 HLA-DR3, and these haplotypes account for most of the associations between these diseases and HLA-DR3. The MHC haplotype HLA-B15 C4A*3 C4B*3 BF*S HLA-DR4 also carries high risk for type I diabetes in this group of patients. Our data suggest that other DR4+ haplotypes, probably containing C4A*3 C4B*1, carry increased risk for type I diabetes whereas haplotypes containing DR4 and C4 C4A*3 C4B*Q0 do not. Our phenotype data suggest that DR4 in Hashimoto's thyroiditis is frequently associated with HLA-B44, C4A*3, C4B*1 and BF*S.

Alleles↗
PubMed1986

The management of severe brittle diabetes with "Infusaid" implantable pumps.

Two severely brittle diabetic patients were treated with "Infusaid" implantable insulin infusion pumps. Both were young females with recurrent ketoacidosis, prolonged or repeated hospital admissions, and subcutaneous insulin resistance. They also had psychological problems, and had seriously interfered with their treatment to induce glycaemic instability. Delivery of insulin from the pumps was intravenous (i.v.) in one patient, and intraperitoneal (i.p.) in the other. Following implantation, there was a marked improvement in glycosylated haemoglobin level (HbA1), fasting blood glucose (BG), daily insulin dose and hospitalizations. The beneficial effect has continued to date (9 months, and 12 months follow-up) with no major problems.

Adult↗
PubMed1985

Group comparisons of blood pressure and indices of obesity and salt intake in Pacific populations.

Group comparisons of blood pressure and indices of obesity and salt intake from epidemiological studies conducted in the Pacific early in the 1980s are presented. The comparisons were of a rural-urban type, and showed a trend for a lower prevalence of hypertension and for lower mean blood pressures in adults from rural areas, compared with urban populations. Rural residents were also slimmer and appeared to have a lower salt intake than did urban dwellers. These findings give possible support to the role of adiposity and salt intake in the genesis of essential hypertension.

Adult↗
PubMed1985

Serological markers of hepatitis B infection in Niue children.

Hepatitis B infection is hyperendemic in the adult population of Niue. In order to determine the age at which infection is acquired and the contribution of vertical and horizontal transmission, the sera from 1055 children were tested for markers of hepatitis B infection. Eleven percent (11.0%) were found to be carriers of hepatitis B surface antigen (HBsAg) and a further 33.6% had antibody to hepatitis B surface antigen (anti-HBs). While less than 15% of the population were infected before the age of two years, these children had the greatest risk of becoming chronic carriers. The simplest method of controlling hepatitis B infection in Niue would be to immunise all newborn babies.

Adolescent↗
PubMed1985

An epidemic of influenza in the population of Niue.

An epidemic of influenza A occurred in the Niue population during May-June 1983. The infection was introduced by two index cases returning from New Zealand to the village of Makefu. The epidemic started in this village and then spread rapidly around the island. The incidence of infection was calculated to be 41 per 100 population based on 1981 census figures. There was no predilection for the infection to affect any particular age bracket, although the elderly were over-represented amongst the hospital admissions because of greater severity of illness in this age group. Two deaths occurred, and 3.4% of cases received treatment in hospital. Apart from generalised symptoms (fever, body pain, and headache), respiratory symptoms, particularly cough, were prominent. Gastrointestinal symptoms were reported in a minority. The average duration of illness was 6 days. Virology results indicated that the epidemic was due to influenza A/Bangkok/1/79(H3N3). Paired serological studies also revealed five cases of dengue fever. Previous records reveal that epidemics of influenza are a frequent occurrence in Niue, although not a major cause of mortality since the 1950s. It is suggested that early treatment of complications is the most important measure to decrease the impact of influenza and that measures such as isolation of cases, restriction of population movement and quarantine of incoming cases may be useful to prevent the propagation of epidemics in a small and isolated population.

Adolescent↗
PubMed1985

Biological effects of sulphated insulin in adipocytes and hepatocytes.

The binding affinity of sulphated insulin compared with unmodified, neutral insulin has been reported to be approximately four times lower in human and rat adipocytes but over twenty times lower in rat hepatocytes. In the present study the biological action of sulphated insulin was assessed in rat hepatocytes and human and rat adipocytes. To achieve half-maximal stimulation of fatty acid synthesis in rat hepatocytes about twenty one times higher concentrations of sulphated than neutral insulin were required (15.07 +/- 5.50 vs 0.71 +/- 0.34 nmol/l), this ratio being similar to the ratio of binding affinity in rat hepatocytes. In human adipocytes, half-maximal stimulation of initial rates of glucose uptake was observed at 11.6 +/- 5.1 vs 2.9 +/- 1.3 pmol/l for sulphated and neutral insulin respectively, and half-maximal inhibition of lipolysis at 31.0 +/- 13.5 vs 7.3 +/- 2.5 pmol/l respectively. These data are consistent with the four-fold lower binding affinity of sulphated insulin to human adipocytes. However, in rat adipocytes the biological potency of sulphated insulin was found to be much lower than anticipated from the binding data, half-maximal stimulation of initial rates of glucose uptake being observed at 757 +/- 299 vs 35 +/- 13 pmol/l respectively and half-maximal inhibition of lipolysis at 35.9 +/- 12.1 vs 1.5 +/- 0.5 pmol/l respectively. Thus, in rat adipocytes, approximately 22 times the concentration of sulphated insulin was required to achieve equivalent biological effect. A discrepancy between binding affinity and biological action with respect to sulphated insulin was identified in rat adipocytes but not human adipocytes nor rat hepatocytes suggesting differences in the binding-action linkage in these cells.

Adipose Tissue↗
PubMed1985

The psycho-social consequences of intermittent husband absence: an epidemiological study.

This paper examines the psycho-social effects on wives of their husbands' intermittent absence on off-shore oil rigs. It is based on data gathered from a random sample of wives living in the Aberdeen area, and it proceeds in three stages. The analysis begins with a comparison between wives whose husbands work on- and off-shore, it goes on to examine differential reaction to husband absence in the off-shore group and concludes with an attempt to estimate prevalence of the 'intermittent husband syndrome'. All the available evidence suggests that the psycho-social effects of intermittent husband absence have been exaggerated. The mental and physical health of wives of men working off-shore was similar in most respects to the health of wives whose husbands work on-shore. Within the sample of wives whose husbands worked off-shore those most affected by intermittent husband absence were 'Novices' (newly married wives with preschool children and no previous experience of husband absence), those with outside employment and those experiencing irregular absences. But even among such groups with fairly pronounced mood and behaviour changes there was little evidence of raised levels of morbidity. When defined in terms of specified levels of reactivity, marital conflict and morbidity prevalence of the 'intermittent husband syndrome' was found to be around 10%.

Adjustment Disorders↗
PubMed1985

Diabetes in Wallis Polynesians: a comparison of residents of Wallis Island and first generation migrants to Noumea, New Caledonia.

A comparative study of diabetes, impaired glucose tolerance and obesity was undertaken in samples of rural Wallisians of Wallis Island and first generation Wallisian migrants in the urban centre of Noumea, New Caledonia. Approximately 20-25% of the adult population of the 2 communities was included in the study. Wallisians in Noumea tended to be more obese than those in Wallis (particularly females). The prevalence of diabetes was 7 and 4 times higher in Noumea compared to Wallis for males and females respectively. Differences in the extent of obesity appeared to account for some of the difference in prevalence of diabetes, but other environmental factors (such as constituents of the diet, and exercise) must be operative as well. The results of this study are consistent with previous findings concerning environmental determinants of diabetes in Pacific populations.

Adult↗
PubMed1985

Response competition in recognition memory in three amnesic groups.

Experimental studies have suggested that a feature of the memory defect in some amnesic conditions may be a failure to inhibit competing responses at retrieval. It is not known whether this feature is present equally in different syndromes involving amnesia. Employing a recognition memory paradigm with varying numbers of response alternatives (based on Miller, 1978), three amnesic groups (Korsakov's, senile dementia, and multi-infarct dementia) were compared using four types of test material. The groups were not differentially affected by increasing numbers of response alternatives.

Aged↗
PubMed1985

Serum lactate dehydrogenase and creatine kinase during marathon training.

Serum total creatine kinase (CK) and the lactate dehydrogenase (LDH) isoenzymes were studied in 38 sedentary middle-aged men (aged 35-50 yrs) during a 30 week marathon training programme. Basal CK activity rose by 33% after 15 weeks but a significant rise (27%) in LDH activity took 30 weeks to occur. Post-exercise (maximum test on a bicycle ergometer) CK and LDH activities were higher than pre-exercise levels but the increment in enzyme activity following exercise did not change. LDH1 and LDH2 isoenzyme activity increased by 2.5% and 4% of total LDH respectively while LDH3 and LDH5 decreased by 3.9% and 2.4% respectively over 30 weeks. Post marathon total CK did not correlate with finishing time at 30 mins or 30 hrs post race. The range of CK MB isoenzyme activity at 30 mins post race was 1.8-9.8% of total CK with 11 subjects having a value above 6%. The training programme appears not to have affected muscle CK and LDH release during exercise but isoenzyme distribution changes reflect the adaptations known to occur in muscle during endurance training. Unfortunately only 16 subjects were available for all the investigations, and it is these upon whom most of the data were obtained.

Adult↗
PubMed1985

Rapid development of obstructive sleep apnea following hemidiaphragmatic and unilateral vocal cord paralysis as a complication of mediastinal surgery.

We describe a patient with obstructive sleep apnea (OSA) who is unusual in two respects: 1) rapid development of severe OSA over a period of two to four months, and 2) direct temporal association between development of OSA and mediastinal surgery complicated by unilateral paralysis of the phrenic nerve and the recurrent laryngeal nerve.

Carcinoid Tumor↗