Search PubMed⌕ Search

Biomedical subjects

R Taylor

Publications and source records attributed to R Taylor.

At least 469 records · Page 26Linked to original sources
PubMed1989

Capillary column gas chromatography-mass spectrometry for the determination of the fatty acid composition of human adipose tissue.

A procedure for determining the fatty acid composition of human adipose tissue using gas chromatography-mass spectrometry was developed. Adipose tissue was obtained from the lateral upper aspect of the right thigh by needle biopsy and prepared for analysis by lyophilisation, total lipid extraction and base-catalysed transesterification of the complexed fatty acids to form fatty acid methyl esters. Capillary column gas chromatography resolved thirty different peaks, ranging in carbon length from 12 to 24. Provisional identification of the peaks was by cochromatography with authentic standards and confirmed by gas chromatography-mass spectrometry using electron-impact ionisation. Fatty acid methyl esters were quantified in absolute amounts with respect to dry tissue weight and as a percentage of the total fat. Statistical analysis of the results from twenty healthy subjects using the two-tailed unpaired Student's t-test demonstrated women had significantly higher levels of myristoleic and palmitoleic acids (p less than 0.001) and lower levels of palmitic acid (p less than 0.05) in adipose tissue when compared with the male group. Similarly total saturated fatty acids was lower (p less than 0.05) and total monounsaturated fatty acids was higher in women than in men.

Adipose Tissue↗
PubMed1989

In vitro study of human skeletal muscle strips: effect of nonesterified fatty acid supply on glucose storage.

To examine the effect of increased nonesterified fatty acid concentration on glucose storage in human muscle, an in vitro method for study of glycogen synthesis in this tissue has been established. Muscle strips obtained from rectus abdominus during elective abdominal surgery were clamped at resting length, and adenosine triphosphate/total adenosine nucleotide ratios remained constant for 3 hours ex vivo. Leakage of enzyme markers of muscle damage was minimal, and electron microscopy showed preserved myofibril ultrastructure. Insulin stimulation brought about a dose-dependent increase in rates of glycogen synthesis with a half-maximal effect at 9 x 10(-10) mol/L insulin. In 15 consecutive studies, basal rates of glycogen synthesis were 4.1 +/- 0.5, 3.2 +/- 0.7, and 3.0 +/- 0.3 nmol glucose/25 mg/h in the absence of palmitate, with 1.4 mmol/L and 2.8 mmol/L palmitate, respectively. Insulin-stimulated rates of glycogen synthesis were 8.6 +/- 1.2, 6.0 +/- 1.8, and 5.8 +/- 0.8 nmol glucose/25 mg/h. Thus, increasing fatty acid concentrations decreased rates of glycogen synthesis both basally and with insulin stimulation. The insulin signal itself was not affected as the percentage stimulation over basal rates remained approximately constant in the presence or absence of fatty acid (2.1-, 1.9- and 1.9-fold, respectively). Insulin sensitivity in vivo is usually expressed as absolute rates of glucose uptake during euglycemic hyperinsulinemia, and if plasma fatty acid elevation were to be studied in vivo an erroneous conclusion may be reached of resistance to hormone action per se.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Two types of delinquents and their institutional adjustment.

This research tested a typology classifying 326 incarcerated delinquent boys as buoyant or beset, depending on their level of anxiety and depression at intake. Findings reveal that the two types of boys differed in some aspects of life history and personality, that the buoyant type adjusted better to the institution's group-oriented treatment program, and that buoyant and beset boys responded differentially to some components of the treatment. Implications are drawn regarding the usefulness of the typology for guiding differential treatment.

Adaptation, Psychological↗
PubMed1989

Hepatic and peripheral insulin action in chronic renal failure before and during continuous ambulatory peritoneal dialysis.

1. A three-step hyperinsulinaemic euglycaemic clamp was performed in six uraemic patients before dialysis and after 3 months of treatment with continuous ambulatory peritoneal dialysis, and in seven matched normal control subjects. Glucose turnover was assessed basally and during the clamp using [3-3H]glucose as a tracer. 2. The glucose infusion rate required to maintain euglycaemia was insignificantly higher in normal subjects compared with undialysed uraemic subjects at each insulin infusion rate. 3. The isotopically assessed total glucose turnover was also similar in normal and uraemic subjects. Basal hepatic glucose output was again similar in uraemic and control subjects and output was suppressed to a similar degree at each insulin infusion rate. 4. After treatment with continuous ambulatory peritoneal dialysis, the glucose infusion rate and the total glucose turnover during the clamp rose significantly at all three insulin concentrations (P less than 0.05), but remained insignificantly different from normal control values. Hepatic glucose output was unchanged. 5. Peripheral insulin action was improved during continuous ambulatory peritoneal dialysis, but hepatic insulin action was unchanged.

Adult↗
PubMed1989

Receptor binding and biological potency of despentapeptide insulin.

The receptor binding and biological potency of despentapeptide insulin (DPI) was assessed in human adipocytes, rat adipocytes and rat hepatocytes. DPI displayed a lower affinity for binding to both human adipocytes (half-maximum displacement at 0.89 +/- 0.04 and 0.20 +/- 0.02 nmol/l for DPI and insulin respectively; P less than 0.001) and rat adipocytes (half-maximum displacement at 7.12 +/- 1.06 and 1.14 +/- 0.18 nmol/l respectively, P less than 0.05). However, although DPI was less potent than unmodified insulin in stimulating glucose uptake in rat adipocytes (half-maximal stimulation at 2.0 +/- 0.67 and 0.47 +/- 0.18 nmol/l respectively; P less than 0.05), DPI was equipotent with insulin in human adipocytes (half-maximal stimulation at 0.034 +/- 0.001 and 0.027 +/- 0.001 nmol/l respectively; P greater than 0.2). In rat hepatocytes, DPI was twofold less potent in binding displacement activity (half-maximum displacement at 3.8 +/- 0.9 and 1.7 +/- 0.3 nmol/l respectively; P less than 0.01) but appeared to be equivalent in stimulating amino butyric acid uptake (half-maximum stimulation at 0.98 +/- 0.12 and 0.95 +/- 0.26 nmol/l respectively). The difference in affinity of DPI binding to rat liver membranes was less marked (1.3 fold decreased compared with insulin: 5.3 +/- 0.7 and 4.2 +/- 0.6 nmol/l respectively; P less than 0.001). Thus, the decreased receptor affinity of DPI was reflected in decreased biological potency in rat adipocytes, but not in human adipocytes nor rat hepatocytes. These data suggest differences in the binding-action linking in the cells of different tissues and different species.

Adipose Tissue↗
PubMed1989

A cross-sectional ecological analysis of blood pressure and its determinants in eleven Pacific populations.

A cross-sectional interpopulation analysis of blood pressure and its determinants was conducted with the data collected during epidemiologic surveys in 11 Pacific island populations from 1975 to 1981. In each of these populations, the mean arterial blood pressure increased with age; the overall blood pressure levels differed among the populations. The multivariate analyses suggest that dietary factors that result in differences in body mass, plasma cholesterol, and glucose intolerance contribute considerably to interpopulation differences in blood pressure. The impact of these differences in effects of dietary factors on interpopulation blood pressure seemed to be uniform, even though the overall levels of each of these three variables differed significantly among the populations. This study of blood pressure data, accrued from 6224 men and 7029 women aged 20-79 years, supports the hypothesis that dietary factors strongly contribute to high blood pressure as well as to interpopulation differences in the prevalence of hypertension. We propose using these data in planning programs for prevention and control of hypertension in the Pacific countries.

Adult↗
PubMed1989

Blood pressure changes with age in two ethnic groups in Fiji.

Blood pressure was studied in urban and rural samples of the Melanesian and Indian populations of Fiji during a National Cardiovascular Disease and Diabetes Survey in 1980. Mean blood pressures rose with age and tended to be higher in urban than in rural populations, particularly in the middle age range. There was no clear or significant difference between the ethnic groups. When the prevalence of hypertension was studied (using WHO criteria) similar age, geographic and ethnic differences were found. Comparisons with data from 1960 revealed no significant change in mean blood pressures during the 20-year interval. Rural populations were leaner and appeared to consume less salt than did urban groups. There were positive and significant correlations between blood pressure and triceps skinfold thickness in most subgroups.

Age Factors↗
PubMed1989

Societies in transition: mortality patterns in Pacific Island populations.

The 22 Pacific Island countries and territories are in a state of demographic and epidemiological transition. Mortality data for the period around 1980 were collected from various sources and are presented in this comparative study. Because death registration in many Pacific countries is deficient some data have been adjusted for underenumeration; and some mortality estimates have been calculated by indirect means, using data from censuses or surveys. Cause of death information is affected by diagnostic inaccuracy and often tabulated in broad categories only; in some Pacific countries cause of death data are only available on hospital deaths. The less developed Melanesian malarious countries and the less developed dispersed atoll nations manifest higher mortality, and higher proportional mortality from infectious disease compared with other states. The more developed US-associated states, two New Zealand-associated states, and New Caledonian Europeans all have reasonably low mortality, and relatively high proportional mortality from cardiovascular disease (CVD). Females have longer life expectancy at birth than males in all countries except Vanuatu and the Solomon Islands. The phosphate-rich island of Nauru presents an atypical picture with considerable adult male mortality from diseases associated with modernization.

Adolescent↗
PubMed1989

Aetiology of non-insulin dependent diabetes.

The importance of genetic factors in the aetiology of NIDDM has been underlined by study of family pedigrees and identical twin pairs. Although in some isolated populations and a tiny minority of Western families inheritance follows an autosomal dominant pattern, a polygenic mode of transmission predominates in Europe and North America. No genetic markers have been identified despite intensive study of the HLA system and gene polymorphisms. Environmental factors appear to play some role, but examination of the evidence for an aetiological effect of the commonly assumed factors, diet and obesity, suggests that they exert no direct effect. However, it is likely that these factors together with physical inactivity could modulate the speed of progression to symptomatic disease. Both beta cell dysfunction and tissue insulin insensitivity are important in producing the syndrome of NIDDM. Insulin insensitivity is present from very early in the time course of the syndrome, but it is clear that the disease cannot develop in the absence of beta cell dysfunction. The recent discovery of islet associated amyloid is exciting as it represents a major step in tracing the pathogenesis of NIDDM backwards towards genetic and non-genetic aetiological influences.

Aging↗
PubMed1989

New ways to look at the architecture of plant cell walls : localization of polygalacturonate blocks in plant tissues.

We report the use of Ni(2+) and Co(2+) on free-hand sections of soybean (Glycine max L.) and Bidens sp to localize polygalacturonates. In soybean only the hourglass cells of the seedcoat stain intensely. In the pod the epidermis of the outer pod wall and a few layers of subepidermal cells stain lightly, while that part of the funiculus adjacent to the seedcoat palisade epidermal cells stains heavily and the neck of the funiculus close to the pod also stains. In Bidens stem sections, the walls of the collenchyma stain most intensely.

Journal Article↗
PubMed1989

Return of fertility after twelve years of autoimmune ovarian failure.

Autoimmune ovarian failure is widely regarded as irreversible, although ovarian biopsy characteristically shows follicles surrounded by lymphocytes. Two previous reports of pregnancy in this condition both followed institution of steroid replacement therapy (Finer et al., 1985; Cowchock et al., 1988). We report a case in which fertility spontaneously returned to normal twelve years after the diagnosis of autoimmune ovarian failure.

Adult↗
PubMed1989

A study of familial hypercholesterolaemia in Iceland using RFLPs.

We have studied 17 unrelated families from Iceland who have familial hypercholesterolaemia (FH), using three different restriction fragment length polymorphisms (RFLPs) of the LDL receptor gene. In one family FH was caused by a 2 kb deletion in the LDL receptor gene in the region of exons 9 to 10. The PvuII (intron 15), NcoI (exon 18), and ApaLI (intron 15) RFLPs were used to determine the haplotypes associated with the defective LDL receptor gene in Iceland. Genotypes were determined in 77 subjects from these 17 families, both FH and non-FH. A rare new NcoI RFLP was detected in three subjects. Among the patients, at least four different haplotypes were observed indicating that FH in Iceland is caused by at least four different mutations and is a heterogeneous disease, even in the small, geographically isolated population of Iceland.

Adult↗
PubMed1989

Toxic reaction to inhaled paint fumes.

An acute confusional state was observed to follow heavy exposure to polyurethane gloss paint fumes in a previously healthy 60 year old man. This state remitted over a 3-day period, but was followed by transient bone marrow suppression and evidence of liver cell damage. The corroborated absence of other toxins and the temporal association of exposure to paint fumes suggest that a volatile paint component was responsible. White spirit is the major volatile solvent in polyurethane gloss paint. Ingestion of related aliphatic hydrocarbons has been reported to cause nausea, drowsiness and hepatotoxicity, but these symptoms have not previously been documented following excessive inadvertent inhalation of paint fumes.

Air Pollutants↗
PubMed1989

Susceptibility of beige mice to Mycobacterium avium complex infections by different routes of challenge.

We have studied the susceptibility of beige (C57Bl/6/bgJ/bgJ) mice to a virulent strain of Mycobacterium avium complex (MAC) (101) by intravenous, intraperitoneal, intranasal, oral, and intrarectal routes. Consistent with our earlier findings, intravenous challenge resulted in high mortality and colony-forming unit (CFU) counts of recoverable organisms from spleens, lungs, livers, and lymph nodes, plus high levels of mortality. Intraperitoneal challenge resulted in high organ CFU counts but no mortality. Of relevance to the sexual practice of certain homosexual patients with AIDS is the intrarectal route of inoculation, which resulted in extensive involvement of the visceral organs with MAC disease. Multiple challenges by intravenous, oral, or rectal routes resulted in higher CFU counts than did single exposures.

Animals↗
PubMed1989

Hepatitis B infection in Vanuatu: age of acquisition of infection and possible routes of transmission.

Seroepidemiological studies of hepatitis B were carried out on diverse groups of children (477) and adults (629) from the Pacific Island country of Vanuatu. In children under 14 years, prevalences of HBsAg and of all markers were 6% and 53.3% respectively; in adults greater than or equal to 20 years the prevalences were 15% and 70%. Age specific prevalence of hepatitis B infection (all markers) was low in infancy (less than 1 year) but rose sharply afterwards, suggesting that the main mechanism of transmission was horizontal spread. This finding is consistent with other developing country studies from the Pacific Islands and elsewhere. In view of the main ages and mechanisms of transmission of hepatitis B in children in developing countries and the need for simple and inexpensive immunisation strategies in this context, it is recommended that mass vaccination of all infants with hepatitis B vaccine be undertaken in hyperendemic areas.

Adolescent↗