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Biomedical subjects

B F Clarke

Publications and source records attributed to B F Clarke.

At least 19 recordsLinked to original sources
PubMed1992

Factors influencing oral carriage of yeasts among individuals with diabetes mellitus.

A total of 439 individuals with diabetes mellitus were examined for carriage of yeasts by the oral rinse and palatal swab techniques. Eighteen genetic or environment variables were assessed for their contribution to carriage of yeasts. The factor contributing to palatal and oral carriage of yeasts among individuals with insulin dependent diabetes mellitus (IDDM) was age (P < 0.01). The factor contributing to palatal carriage of yeasts among individuals with non-insulin dependent diabetes mellitus (NIDDM) was poor glycaemic control (glycosuria P < 0.01); carriage in the oral cavity as a whole was influenced additionally by non-secretion of ABH blood group antigens (P < 0.05). Introduction of a denture altered the above risk factors. For individuals with IDDM, oral carriage was associated with the presence of retinopathy (P < 0.05); palatal carriage was influenced by poor glycaemic control (HbA1P < 0.01, plasma glucose levels P < 0.05) and age (P < 0.05). For those with NIDDM, palatal carriage was associated with continuous presence of the denture in the mouth (P < 0.01); oral carriage was associated with plasma glucose levels (P < 0.05).

Adult↗
PubMed1992

Neutrophil count and activation in vascular disease.

An elevated peripheral leucocyte count is associated with an increased risk of myocardial infarction and progression of coronary artery disease. The aim of this study was to determine neutrophil count and activation, measured as an increase in plasma neutrophil elastase, in patients with stable ischaemic heart disease, insulin-dependent diabetes mellitus and essential hypertension compared with a comparable group of control subjects. Neutrophil count and neutrophil elastase were raised significantly for patients with ischaemic heart disease (p less than 0.005; p less than 0.002), diabetes mellitus (p less than 0.001; p less than 0.01) and hypertension (p less than 0.05; p less than 0.0001) respectively compared to the control subjects. Neutrophil elastase did not correlate with subject age or leucocyte count. This study confirms the association between leucocyte count and vascular disease, and is consistent with neutrophil activation contributing to the progression of vascular disease.

Adult↗
PubMed1991

A double-blind crossover study of oral xamoterol in postural hypotension due to diabetic autonomic neuropathy.

Recent reports have suggested that xamoterol, a beta 1 adrenoceptor partial agonist with 43% intrinsic sympathomimetic activity improves symptomatic postural hypotension in patients with primary autonomic failure. To evaluate the use of xamoterol in eleven insulin dependent patients with diabetes mellitus who had postural hypotension (over 20 mmHg systolic blood pressure) secondary to autonomic neuropathy, we performed a double-blind, randomized, placebo controlled crossover study with xamoterol (200 mg bd orally) for 1 month. Treatment with xamoterol raised supine systolic blood pressure by 11 mmHg but a reduced standing systolic blood pressure by 11 mmHg with an increase in the standing-supine systolic blood pressure difference. No significant differences were observed in symptom score, HbA1 or plasma glucose. We conclude that oral xamoterol raises supine systolic blood pressure but paradoxically lowers standing systolic blood pressure further in insulin dependent diabetes mellitus. Xamoterol is unlikely to be of value in the management of postural hypotension in diabetic patients with autonomic neuropathy.

Adrenergic beta-Agonists↗
PubMed1991

Hand skin blood flow in diabetic patients with autonomic neuropathy and microangiopathy.

OBJECTIVE: To determine whether changes in hand skin blood flow in diabetic men could be demonstrated with liquid crystal contact thermography and to assess the relative effects of autonomic neuropathy and microangiopathy on these changes. RESEARCH DESIGN AND METHODS: Thirty-four diabetic and 12 age-matched nondiabetic men comprised the study. The diabetic men were categorized according to standard cardiovascular autonomic function tests and the presence or absence of background or proliferative retinopathy and/or proteinuria. Bilateral hand thermograms were measured at rest and after immersion of the right hand in ice-cold water. RESULTS: Diabetic men with definite or severe autonomic neuropathy (n = 13) had a high frequency of anisothermal baseline thermograms (77 vs. 25% in nondiabetic subjects, P less than 0.05). After ice-cold water immersion, right-hand recovery was abnormally slow (514 +/- 157 arbitrary U, area under the curve) compared with nondiabetic men (685 +/- 135 arbitrary U, P less than 0.01). Diabetic men with proliferative retinopathy (n = 8) all had definite or severe autonomic neuropathy and showed the same abnormalities. Diabetic men with nor or early autonomic changes showed normal thermographic patterns. CONCLUSIONS: These results are consistent with increased palmar arteriovenous shunt blood flow or capillary closure in the hands of diabetic patients with definite or severe autonomic neuropathy. They indicate that thermoregulatory reflex changes in hand skin blood flow are controlled by the autonomic nervous system. It is possible, however, that diabetic microangiopathy, associated with the presence of proliferative retinopathy, also independently affects hand skin blood flow.

Adult↗
PubMed1979

Obstetric history of diabetics: its relevance to the aetiology of diabetes.

The birth weights of infants born to patients with insulin-dependent diabetes (IDD) and insulin-independent diabetes (IID) before the disease was diagnosed were compared. An appreciable excess of infants above the 90th centile for weight was found, the proportions being 27% of infants born to mothers with IDD and 30% of those born to mothers with IID. These findings suggest that many patients with both types of diabetes have a prolonged period of metabolic abnormality before overt symptoms of diabetes arise and that the apparent acute onset of the disease in patients who are insulin dependent is illusory.

Adult↗
PubMed1979

Glycosylated haemoglobin concentrations in newly diagnosed diabetics before and during treatment.

Concentrations of total glycosylated haemoglobins (Hb A1) were measured in 40 diabetics at diagnosis and at monthly intervals after treatment with chlorpropamide, insulin, or diet alone was begun. The mean Hb A1 concentration at presentation in 16 patients treated with chlorpropamide was significantly higher than that in 12 patients treated with insulin, and the duration of glycaemic symptoms was much longer in the chlorpropamide-treated group. In contrast, the mean plasma glucose concentration was similar in both groups. The mean concentrations of Hb A1 and plasma glucose at diagnosis in the 12 patients treated by diet alone were lower than those in the other two groups, and most of these patients were free of symptoms. Treatment quickly relieved symptoms and lowered plasma glucose in all patients. The Hb A1 concentration fell significantly with treatment such that after two months there was no significant difference between the three groups, although results remained above the normal range. These findings support the theory that the Hb A1 concentration reflects the blood glucose control over the previous one to two months and suggest that the duration of hyperglycaemia may be important in determining the Hb A1 concentration as well as the absolute blood glucose concentration.

Adult↗
PubMed1979

Seasonal onset of insulin dependent diabetes in relation to sex and age at onset.

All newly diagnosed insulin dependent diabetics presenting consecutively to the Diabetic Department of the Royal Infirmary from the City of Edinburgh or its environs, between the years 1964 and 1977, were analysed for sex (297 males, 205 females), age at diagnosis (range 10--75 years), month of diagnosis, duration of symptoms and month of symptomatic onset. Males aged 10--19 years showed a significant seasonal variation in diagnosis (p less than 0.025) with an increase in autumn and winter months which was not seen in females aged 10--19 years nor in patients of either sex aged more than 19 years at diagnosis. The duration of diabetic symptoms increased with increasing age at diagnosis in both males and females and was consistently greater in females than in males for each age group at diagnosis. When the month of symptomatic onset was considered in relation to sex and age at diagnosis, having excluded patients with duration of symptoms of more than three months, only males aged 10--19 years at diagnosis showed a significant seasonal variation in incidence (p less than 0.005).

Adolescent↗
PubMed1979

Diabetic autonomic neuropathy.

This review attempts to outline the present understanding of diabetic autonomic neuropathy. The clinical features have been increasinly recognised but knowledge of the localization and morphology of the lesions and their pathogenesis remains fragmentary. A metabolic causation as postulated in somatic nerves accords best with clinical observations. Most bodily systems, particularly the cardiovascular, gastrointestinal and urogenital, are involved with added disturbances of thermoregulatory function and pupillary reflexes. Possible effects on neuroendocrine and peptidergic secretion and respiratory control await definition. Current interest centres around the development of a new generation of tests of autonomic nerve function that are simple, non-invasive, reproducible and allow precision in diagnosis and accurate quantitation. Most are based on cardiovascular reflexes and abnormality in them is assumed to reflect autonomic damage elsewhere. Probably no single test suffices and a battery of tests reflecting both parasympathetic and sympathetic function is preferable. Little is known of the natural history. The prevalence may be greater than previously suspected and although symptoms are mild in the majority, a few develop florid features. The relation of control and duration of diabetes to the onset and progression of autonomic neuropathy is not clearly established. Once tests of autonomic function become abnormal they usually remain abnormal. Symptomatic autonomic neuropathy carries a greatly increased mortality rate possibly due to indirect mechanisms such as renal failure and direct mechanisms such as cardio-resiratory arrest. Improved treatment of some of the more disabling symptoms has been possible in recent years.

Autonomic Nervous System↗
PubMed1979

Non-invasive assessment of left ventricular response to Valsalva manoeuvre in normal and diabetic subjects using praecordial accelerocardiography.

The left ventricular response to the Valsalva manoeuvre was studied in 5 normal subjects (group 1), 6 diabetics without autonomic neuropathy (group 2), and 5 diabetics with autonomic neuropathy (group 3), using the maximum amplitude of the praecordial accelerocardiogram (DE) as a noninvasive index of left ventricular performance. During the Valsalva manoeuvre DE decreased in all 3 groups. In groups 1 and 2, DE increased significantly above the control value after release of the manoveuvre (DE overshoot) but this did not occur in group 3. It is suggested that the overshoot of DE in groups 1 and 2 reflects an increase in left ventricular contractility after release of the Valsalva manoeuvre and the absence of an overshoot in DE in the patients with autonomic neuropathy is the result of loss of cardiac adrenergic innervation. The ability to detect an abnormal cardiovascular response to the Valsalva manoeuvre using the non-invasive technique of praecordial accelerocardiography may be of practical value in the assessment of left ventricular function.

Adult↗
PubMed1979

Mononeuropathy in diabetes mellitus.

Fifty-one diabetic patients with mononeuropathies wereoneuropathy were studied to examine possible etiological factors, to determine the relationship with other diabetic complications, and to correlate with the presence and severity of background peripheral and autonomic neuropathy. The median, ulnar, and lateral popliteal nerves were most commonly affected and cranial neuropathy was relatively uncommon. When bilateral involvement of the same nerve was excluded, multiple mononeuropathies were found in only five patients. Median and ulnar mononeuropathy were gradual in onset and affected the dominant limb whereas other types of mononeuropathies were acute in onset with no predilection for either side. No consistent relationship was shown between the onset of mononeuropathy and age, sex, diabetic treatment, duration of diabetes, diabetic control, or other diabetic complications. In particular, there was no significant background peripheral and autonomic neuropathy, as assessed clinically and by objective tests, in almost one-half of the patients studied. It is concluded that diabetic mononeuropathy may occur independently of peripheral and autonomic neuropathy. It is possible, however, that a minimal degree of background damage, known to be present in all diabetic patients, may render them more susceptible than the general population to the various factors causing mononeuropathy.

Abducens Nerve↗