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Biomedical subjects

R Taylor

Publications and source records attributed to R Taylor.

At least 361 records · Page 20Linked to original sources
PubMed1994

Motor apraxia in dementia.

Motor apraxia was assessed in 25 patients with presumed dementia of the Alzheimer type and 23 patients with presumed multi-infarct dementia. Apraxia was common in both groups and was usually only mild. It correlated most strongly with language-related impairments in the Alzheimer group, as has been found in other patient groups, whereas in the group with multi-infarct dementia the pattern of correlations was less clear. It was not strongly related to performance on tests involving constructional praxis or to age in either group. Implications of the findings for clinical assessment are noted.

Aged↗
PubMed1994

Turnover of human muscle glycogen with low-intensity exercise.

To determine whether glycogen turnover occurs during prolonged low-intensity exercise, five subjects performed plantar flexion of the right leg at 15% MVC for 5 h. At rest and during the initial 2.5 h of exercise gastrocnemius glycogen was monitored in both legs with natural abundance 13C NMR. At 2.5 h exercise, a step-up infusion of 99% enriched 1-13C glucose was begun and maintained over the next 1.5 h of continued exercise to monitor 1-13C glucose incorporation into the exercising muscle's glycogen pool. Exercise was continued for an hour following the infusion, and NMR scans were performed throughout the session. During the first 2 h of exercise, glycogen 1-13C signal amplitudes dropped approximately 30% and remained there at 2.5 h, indicating that glycogen concentration had leveled. Following infusion, glycogen signal amplitudes rose to 123% of resting values, remaining there during an hour of subsequent exercise. There was no change of glycogen 1-13C signal in the nonexercising leg. Venous glucose levels remained stable until the infusion was begun and then rose < 7% (5.57-5.96 mmol.l-1) during the infusion. Venous insulin and C-peptide levels did not change during the infusion. We conclude that the human gastrocnemius can degrade and synthesize glycogen simultaneously during prolonged low-intensity exercise.

Adult↗
PubMed1994

Nephropathy and changes in sodium-lithium countertransport kinetics in type 2 (non-insulin-dependent) diabetes mellitus.

Previous studies of erythrocyte sodium-lithium countertransport activity, a putative genetic marker of essential hypertension, in Type I and Type II diabetic patients with nephropathy have given conflicting results. We have found changes in the maximum velocity (Vmax) and sodium-affinity constant (Km) of sodium-lithium countertransport in Type I diabetic patients with diabetic nephropathy. In this study, sodium-lithium countertransport kinetics were measured in Type II diabetic patients with established diabetic nephropathy, matched uncomplicated Type II diabetic patients, non-diabetic patients with nephropathy and healthy control subjects. Mean standard sodium-lithium countertransport activity was not significantly increased in either of the groups of diabetic patients compared with the non-diabetic control groups. The Type II diabetic patients with nephropathy had a significantly reduced km and Vmax compared with the uncomplicated diabetic patients and non-diabetic control group. These kinetic changes are identical to those observed in Type I diabetic nephropathy patients. There are similar underlying changes in the erythrocyte plasma membrane with the development of nephropathy in both Type I and Type II diabetes.

Antiporters↗
PubMed1993

Merkel-like basal cells in Necturus taste buds contain serotonin.

Several types of cells have been identified in vertebrate taste buds, including dark cells, light cells, intermediate cells, type III cells, and basal cells. The physiological roles of these cell types are not well understood, especially those of basal cells. In this paper we show that there are two types of basal cells in taste buds from Necturus maculosus. One type of basal cell is an undifferentiated cell, presumably a stem cell. By combining light microscopic immunocytochemistry with electron microscopy, we show that the other type of basal cell is positive for serotonin-like immunoreactivity and that these cells have ultrastructural features similar to those found in cutaneous Merkel cells. Based on these findings, and the fact that the Merkel-like taste cells have been shown to make synaptic contacts with adjacent taste cells and with innervating nerve fibers, we conclude that these Merkel-like basal taste cells are serotonergic interneurons.

Animals↗
PubMed1993

Non-communicable diseases in the tropics.

The way of life in many developing countries in the tropics is in a state of transition--from traditional to "modern", with its associated industrialisation, urbanisation and cultural readjustment. Infectious diseases are giving way to non-communicable diseases, such as cardiovascular diseases, adult onset diabetes, cancers, trauma and non-infectious respiratory diseases, as major causes of morbidity and premature mortality. The epidemiology, causality, prevention and treatment of these conditions is summarised in the context of developing countries.

Cardiovascular Diseases↗
PubMed1993

Eosinophilia-myalgia syndrome: lessons for public health researchers.

OBJECTIVE: To review epidemiological investigations into the epidemic of eosinophilia-myalgia syndrome which occurred predominantly in the United States of America in mid to late 1989, and examine the implications for similar urgent public health research in Australia. DATA SOURCES: Published data from epidemiological research, and relevant regulatory statements. OUTCOME: Intensive epidemiological investigations established that eosinophilia-myalgia syndrome was strongly associated with ingestion of L-tryptophan produced by a single manufacturer. It is likely that an identified contaminant has a role in pathogenesis, although the mechanism of action remains unclear. CONCLUSIONS: Rapid epidemiological investigation led to early containment measures and prevention of further public exposure to the causative agent. The episode highlighted the importance of preparedness amongst public health organisations to promptly initiate investigations of disease outbreaks, and demonstrated the benefits of a nation-wide ability to coordinate these studies. There may be encumbrances to urgent public health research in the form of inadequate mechanisms of data linkage. It is recommended that attention be given to such barriers now rather than in a time of crisis.

Australia↗
PubMed1993

The impact of metformin therapy on hepatic glucose production and skeletal muscle glycogen synthase activity in overweight type II diabetic patients.

The effect of metformin therapy on glucose metabolism was examined in eight overweight newly presenting untreated type II diabetic patients (five males, three females). Patients were treated for 12 weeks with either metformin (850 mg x 3) or matching placebo using a double-blind crossover study design; patients were studied at presentation and at the end of each treatment period. Insulin action was assessed by measuring activation of skeletal muscle glycogen synthase (GS) before and during a 4-hour hyperinsulinemic euglycemic clamp (100 mU.kg-1 x h-1). Metformin therapy was associated with a significant decrease in fasting blood glucose (6.8 +/- 0.6 v 8.3 +/- 0.9 mmol.L-1, P < .01) and glycosylated hemoglobin ([HbA1] 7.7% +/- 0.4% v 8.5% +/- 0.5%, P < .01) levels. Fasting hepatic glucose production (HGP) was also significantly decreased following metformin therapy (1.98 +/- 0.13 v 2.41 +/- 0.20 mg.kg-1 x min-1, P < .02), whereas fasting insulin and C-peptide concentrations remained unaltered. The decrease in basal HGP correlated closely with the decrease in fasting blood glucose concentration (r = .92, P < .001). Insulin-stimulated glucose uptake was assessed using the hyperinsulinemic euglycemic clamp technique and was increased post-metformin (3.8 +/- 0.6 v 3.1 +/- 0.7 mg.kg-1 x min-1, P < .05). This was primarily the result of increased nonoxidative glucose metabolism (1.1 +/- 0.6 v 0.4 +/- 0.6 mg.kg-1 x min-1, P < .05); oxidative glucose metabolism did not change. Metformin had no measurable effect on insulin activation of skeletal muscle GS, the rate-limiting enzyme controlling muscle glucose storage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Suicide and unemployment in Australia 1907-1990.

Ever since Durkheim postulated a relationship between economic change and suicide there has been evidence of a general association between aggregate data on unemployment and the frequency of suicide. Quantitatively, however, the association has been variable and it is clear that due to differing cultural, social and individual determinants of suicide, the relationship is complex. Methodological difficulties abound with interpretation of aggregate data. Australian records for most of the present century are suitable for examining secular trends in suicide and unemployment by age group and gender to gain an indication of the extent to which both parameters may be causally related. An aggregate/ecological study was designed to incorporate quantitative and qualitative strategies. Annual age-adjusted male and female suicide rates and annual unemployment rates were derived for the period 1907-1990. Female suicide rates were generally stable throughout the period, whereas those for males demonstrated sharp fluctuations with the peaks coinciding with times of high unemployment. The association between suicide and unemployment for 15-24 year old males was comparatively high for the recent period, 1966-1990. The increasingly youthful contribution to male suicide was demonstrated by a rise in the loss of life years during 1973-1984. Despite the inability of any investigation based on aggregate data to establish an unequivocable causal relationship, no evidence was detected to suggest that relatively high population levels of unemployment were not related to the occurrence of suicide.

Adolescent↗
PubMed1993

Management of non-insulin-dependent diabetes.

Understanding the management of non-insulin-dependent (type 2) diabetes (NIDDM) requires the grasp of three concepts. Firstly, the condition is steadily progressive and demands appropriate changes of therapy over time. Secondly, therapeutic aims must be set for three parameters: plasma lipids, plasma glucose and blood pressure. Thirdly, the condition is dangerous and regular screening for early complications is mandatory. In this brief review the nature of NIDDM is discussed and an approach to clinical management outlined.

Blood Glucose↗
PubMed1993

The use of a computer-assisted telephone interview technique in a general practice research study.

We describe the principles and practice of computer-assisted telephone interviewing, and its successful deployment in a general practice-based research study into the referral behaviour of general practitioners (GPs) in the Grampian region of Scotland. Participating GPs were interviewed concerning the acceptability of the method. It proved to be an efficient and acceptable method for collecting data from a large number of practitioners in this large geographical area. Our experience confirms that this efficient method of data collection could be much more widely utilized in primary care research.

Computers↗
PubMed1993

Childhood injury mortality in New South Wales: geographical and socio-economic variations.

This paper reports a retrospective study of deaths due to unintentional injury in children aged between 0 and 14 years of age in New South Wales between 1985 and 1987. The aims were to determine whether the pattern of child injury mortality differed between rural and metropolitan New South Wales and to establish the relationship between socio-economic status, based on a geographical indicator of socio-economic status and child injury mortality. The child injury mortality rate for New South Wales in 1985-87 was 12.3 deaths per 100,000 population per year. The rate in the country area of 15.3 deaths per 100,000 was significantly higher than that for the metropolitan area of 11.3 per 100,000 (P < 0.05). Deaths of passengers in motor vehicle traffic accidents (P < 0.01) and deaths due to fires (P < 0.01) were greater in the country area. A negative linear association between socio-economic status and child injury mortality was found in the Sydney metropolitan area (P < 0.01). This trend was most apparent for deaths of child pedestrians (P < 0.01).

Accidents↗
PubMed1993

Risks of premature death from smoking in 15-year-old Australians.

This cross-sectional actuarial analysis of 1990 mortality data aimed to estimate absolute risk of premature death from all causes, and from lung cancer, ischaemic heart disease and chronic bronchitis/emphysema due to tobacco smoking in the Australian population, and to estimate the number of current 15-year-old smokers in the 1990 Australian population who will die prematurely due to smoking. Competing risks were allowed for in the calculations. In males, conditional life expectancy for 15-year-olds was 78.0 years in nonsmokers, 73.3 years in ever-smokers, and 71.5 years in smokers of more than one packet a day. For 15-year-old females, life expectancy was 82.0 years in nonsmokers, 78.4 years in ever-smokers, and 76.9 years in smokers of more than one packet a day. The risk of premature death due to smoking in ever-smokers was estimated as 14.6 per cent in males (before 75 years) and 11.9 per cent in females (before 80 years), with lung cancer (male: 4.2 per cent; female: 3.4 per cent), ischaemic heart disease (male: 3.7 per cent; female: 1.7 per cent) and chronic bronchitis/emphysema (male: 2.4 per cent; female: 2.5 per cent) as the major contributors. From one year of 15-year-old male smokers (26,713), 3,916 premature deaths due to tobacco can be expected; this includes 1,106 lung cancer deaths, 991 ischaemic heart disease deaths and 641 chronic bronchitis/emphysema deaths. From one year of 15-year-old female smokers (32,355), 3,861 premature deaths can be expected; this includes 1,086 lung cancer deaths, 559 ischaemic heart disease deaths and 798 chronic bronchitis/emphysema deaths.

Actuarial Analysis↗
PubMed1993

Lymphocyte transformation responses to phytohaemagglutinin and pokeweed mitogen in patients at differing stages of HIV infection: are they worth measuring?

AIMS: To determine whether the routine measurement of lymphocyte transformation responses to mitogenic stimuli provide any information additional to that available from routine T cell CD4 and CD8 analysis in patients with HIV infection. METHODS: The case records of 197 immunologically investigated HIV seropositive patients were reviewed. The influence of disease stage on T lymphocyte subsets and lymphocyte transformation responses (LyTR) to phytohaemagglutinin (PHA) and Pokeweed mitogen was assessed. RESULTS: The median CD3 and CD4 counts and LyTR to PHA and Pokeweed mitogen were highest in patients with persistent generalised lymphadenopathy (PGL) and decreased progressively in the order: asymptomatic patients, those with ARC, those with AIDS. LyTR to PHA was preserved in over 70% of all patients, but the response to Pokeweed mitogen was depressed in 8% of patients with PGL, 34% of asymptomatic patients, 68% of those with ARC and 78% of those with AIDS. Subnormal values of both CD4 + T cells and LyTR to Pokeweed mitogen were more common in patients with ARC and AIDS (68%) than in those who were asymptomatic or had PGL (20%). CONCLUSIONS: CD4 T cell analysis and LyTR to Pokeweed mitogen, but not to PHA, both correlate with disease states in patients with HIV infection.

AIDS-Related Complex↗
PubMed1993

Direct measurement of change in muscle glycogen concentration after a mixed meal in normal subjects.

Postprandial storage of carbohydrate as glycogen in muscle was quantitated in normal subjects (n = 8) by natural abundance 13C-nuclear magnetic resonance spectroscopy with proton decoupling in a 4.7-tesla magnet. After an overnight fast three basal measurements of gastrocnemius muscle glycogen were made and a mixed meal was given. Muscle glycogen concentration rose from 83.3 +/- 5.2 to a maximum of 100.2 +/- 6.7 mmol/l muscle at 4.9 h (P < 0.01) and fell thereafter to 90.6 +/- 5.9 mmol/l muscle at 7 h postprandially (P < 0.006). The meal brought about an increase in plasma glucose from 5.4 +/- 0.2 to 7.3 +/- 0.4 mmol/l at 30 min but this was followed by a rapid fall to 6.2 +/- 0.4 mmol/l at 75 min. Plasma insulin rose from 62.4 +/- 11.4 to 900 +/- 216 pmol/l at 30 min and declined steadily thereafter. It was calculated from total muscle mass measurements and estimation of carbohydrate absorption rates that at peak muscle glycogen concentrations between 26 and 35% of the absorbed carbohydrate was stored as muscle glycogen. These data quantitate the role of skeletal muscle glycogen synthesis in postprandial carbohydrate storage and demonstrate that this tissue acts as a dynamic buffer to maintain glucose homeostasis during postprandial substrate storage.

Adult↗
PubMed1993

Reperfusion injury and exhaled hydrogen peroxide.

Reactive oxygen species have been implicated in the pathophysiology of lung injury associated with the sequence of ischemia-reperfusion. To study this, we measured the exhaled breath hydrogen peroxide concentration [H2O2] in human and canine models of reperfusion lung injury. Our models were patients subjected to cardiopulmonary bypass (CPB) (Group 1), patients undergoing pulmonary thromboendarterectomy (Group 2), canine single lung transplant (Group 3), and patients subjected to peripheral ischemia resulting from aortic cross-clamping or tourniquet application (Group 4). In addition, we studied two groups with severe lung injury as positive controls. These consisted of hydrochloric acid (HCl)-induced canine lung injury (Group 5) and patients with adult respiratory distress syndrome (Group 6). The exhaled H2O2 was collected by using a -2 degrees C glass coil and assayed by a spectrophotometric method. In Group 1 samples were collected before and immediately after CPB. Group 2 samples were obtained before CPB, immediately after CPB, 3 h later, and daily until extubation. Samples in Group 3 were collected before lung transplant, and hourly for 3 h beginning immediately afterward. Group 4 samples were collected at the onset of reperfusion. Samples from Group 5 were collected before HCl and after HCl injury, at 0.5-1.5 and 2-3 h. Group 6 samples were collected when criteria for adult respiratory distress syndrome were met. Groups 1, 3, and 4 exhibited no significant increases in exhaled [H2O2] compared to control values. Group 2 had significantly increased [H2O2] (5.59 +/- 3.07 x 10(-7) mol/L, P = 0.028) on postoperative Day 2, but there was no correlation of [H2O2] with physiologic indicators of lung injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗