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Biomedical subjects

J E Tooke

Publications and source records attributed to J E Tooke.

At least 73 records · Page 4Linked to original sources
PubMed1994

A study of factors governing fluid filtration in the diabetic foot.

The effect of lowering the foot on the factors governing fluid filtration in the foot were studied in 12 male insulin-dependent diabetic subjects and 10 controls. Toe skin blood flow, measured by laser Doppler flowmetry, was significantly higher during dependency in the diabetic group. In the control subjects, the colloid osmotic pressure of venous blood sampled from the foot rose to 47.7 mmHg (range 45.1-53.8) after 50 min of foot dependency. In the diabetic group, colloid osmotic pressure failed to rise to the same extent (median 36.7 mmHg; range 28.6-43.0; P < 0.001). Capillary pressure, measured directly by the Landis microinjection technique, was significantly higher in the diabetic group (85.3 +/- 1.7 (n = 6) vs. 92.2 +/- 4.6 cm H2O (n = 6); P < 0.007), as was foot swelling rate determined by mercury strain gauge plethysmography (0.069 +/- 0.022 vs. 0.099 +/- 0.025 ml min-1 100 ml-1; P < 0.02). These results suggest an impairment of the oedema-preventing mechanisms in diabetic subjects which may contribute to the risks of ulceration in the diabetic foot.

Adult↗
PubMed1994

The influence of hypertension on microvascular blood flow and resistance to flow in the skin of patients with type 2 (non-insulin-dependent) diabetes.

Maximum microvascular blood flow and resistance to flow were determined in the skin of nine hypertensive and nine normotensive Type 2 (non-insulin-dependent) diabetic patients and nine control subjects to determine the influence of hypertension on these variables. Maximum blood flow was reduced in both the hypertensive (1.05 (0.70-1.42) V) and normotensive (1.04 (0.79-1.63) V) Type 2 diabetic patients when compared with control subjects (1.40 (1.26-2.13) V, p < 0.01 for hypertensive and p < 0.05 for normotensive patients, respectively); however, maximum blood flow was similar in both groups of diabetic patients (p = 0.82). In contrast, resistance to flow was significantly greater in the diabetic patients with hypertension (127.2 (87.5-181.3) mmHg V-1 vs 84.7 (61.9-123.0) mmHg V-1 normotensive diabetic patients, p < 0.02). In addition, R was greater in the normotensive Type 2 diabetic patients than in control subjects (70.7 (44.7-79.9) mmHg V-1, p < 0.05). These results suggest that hypertension is associated with an additional rise in pre-capillary vascular resistance in Type 2 diabetes which, while protecting the microcirculation from the effects of increased arterial pressure, may further diminish protective hyperaemic responses.

Aged↗
PubMed1994

Posturally induced vasoconstriction in diabetes mellitus.

In healthy subjects, standing elicits a reduction in blood flow to the skin of the foot. In adults with insulin dependent diabetes this posturally induced response is deficient, resulting in capillary hypertension when the foot is in the dependent position (that is, below heart level). Such functional abnormalities of the microcirculation in diabetes may precede any evidence of clinically detectable microangiopathy. This study investigates the posturally induced change in blood flow to the skin of the foot in prepubertal and postpubertal patients with insulin dependent diabetes. Laser Doppler fluximetry was used to assess the postural change in blood flow at the pulp of the great toe. Postural vasoconstriction (dependent flux value/supine flux value x 100) was greater after puberty in normal subjects (median (range) 60.4 (7.0-164.9)% prepubertal v 20.5 (5.9-101.0)% postpubertal). Prepubertal children with diabetes did not differ from their healthy peers (69.8 (7.2-192.7)% with diabetes v 60.4 (7.0-164.9)% controls); however postpubertal children with diabetes had a significantly impaired postural vasoconstriction (40.6 (7.9-140.2)% with diabetes v 20.5 (5.9-101.7)% controls). Abnormalities in the normal reduction of blood flow on standing occurred in young postpubertal children with diabetes, most of whom were free of complications.

Adolescent↗
PubMed1994

Twenty-four hour ambulatory blood pressure and heart rate in a patient with a predominantly adrenaline secreting phaeochromocytoma.

In this report, we present the symptoms, biochemical investigations, 24 hour ambulatory blood pressure and heart rate recordings in a patient before and following removal of a predominantly adrenaline-secreting phaeochromocytoma. The symptoms were of episodic shaking, faintness, nausea, palpitations, sweating and panic, chest and neck pain with headache, and are consistent with previous reports. Ambulatory blood pressure recording demonstrated that mean daily blood pressure was normal, with normal diurnal variation, and two episodes of severe hypertension and bradycardia coincident with symptoms (MAP 150 mmHg and HR 49 beats/minute, MAP 178 mmHg and HR 29 beats/minute, respectively), not reported in predominantly adrenaline-secreting phaeochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1994

Capillary pressure in patients with NIDDM.

The hemodynamic hypothesis suggests that raised capillary pressure may play a role in the pathogenesis of diabetic microangiopathy. Although patients with non-insulin-dependent diabetes mellitus (NIDDM) and insulin-dependent diabetes NIDDM) develop a similar range of microvascular complications, differences in their expression and prevalence suggest that different pathogenic mechanisms may be operational. Capillary pressure is elevated in IDDM; the aim of this study was to assess whether capillary pressure was also elevated in NIDDM. Twenty-one patients with NIDDM (15 men) and 21 healthy control subjects matched for age, sex, and skin temperature were investigated supine with the hand at heart level. Finger nailfold capillary pressure was measured after direct cannulation at the summit of the capillary loops using glass micropipettes. The groups were matched for skin temperature (30.4 [24.2-33.8] degrees C, median [95% confidence interval], NIDDM patients vs. 30.0 [23.4-33.6] degrees C control subjects), age (62.0 [39.4-72.7] years NIDDM patients vs. 62.0 [39.4-72.0] years control subjects), and both systolic (sBP) and diastolic (dBP) blood pressures (133.0 [111.0-167.3]/78.0 [57.0-89.5] mmHg NIDDM patients vs. 133.0 [114.1-158.9]/80.0 [68.2-88.9] mmHg control subjects). Capillary pressure did not differ in the two groups (17.6 [13.1-21.2] mmHg NIDDM patients vs. 19.1 [14.1-23.6] mmHg control subjects [NS]). There was no correlation of capillary pressure with either HbA1c or glucose; however, there was a negative association between capillary pressure and diabetes duration (Rs = -0.50, P = 0.020).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Oedema in patients with Addison's disease on replacement therapy: glucocorticoid excess and mineralocorticoid deficiency?

Steroid hormones influence mechanisms related to oedema formation, including postural vasoconstriction and vascular tone. We studied fifteen patients (7 male, 8 female) with primary adrenal failure on clinically optimal replacement therapy. Five patients, all female, had clinically detectable oedema. Patients with oedema had evidence of mineralocorticoid deficiency, with increased supine and erect plasma renin activity and greater postural fall in blood pressure. Mean morning plasma cortisol levels were significantly higher in the group with oedema, suggesting they were receiving insufficient mineralocorticoid and a possible relative excess of glucocorticoid. There were no significant differences between patients with and without oedema in lower-limb cutaneous blood flow or in postural vasoconstrictor responses measured by laser Doppler flowmetry. The mechanism of oedema formation is unclear, but appears not to be modulated by haemodynamic mechanisms with expansion of intravascular volume or, in contrast to the known effects of sex hormones, by impairment of postural vasoconstriction. Theoretically, excess glucocorticoid replacement may result in oedema formation, by direct action on vascular tone, by altering capillary permeability, or by influencing other factors such as atrial natriuretic peptide. Measurement of plasma renin activity in conjunction with plasma cortisol profiles may be useful in adjusting replacement therapy in patients with Addison's disease and oedema.

Addison Disease↗
PubMed1993

Increased microvascular fluid permeability in young type 1 (insulin-dependent) diabetic patients.

Microvascular fluid permeability was assessed by determination of the capillary filtration coefficient in the forearm of ten young Type 1 (insulin-dependent) diabetic patients with a short duration of diabetes, satisfactory glycaemic control and minimal evidence of microangiopathy, and ten age- and sex-matched control subjects. A strain gauge plethysmographic method with a computer based logging and analysis system was used. This enabled differentiation between the volume filling and fluid filtration components of the response to venous pressure elevation. The median capillary filtration coefficient was found to be significantly higher in the young diabetic patients in comparison with control subjects (9.2 x 10(-3) ml.min-1.100 g tissue-1.mmHg-1 vs 3.8 x 10(-3) ml.min-1.100 g tissue-1.mmHg-1, p < 0.001). There were no significant correlations between capillary filtration coefficient and either plasma glucose concentration, haemoglobin A1c or duration of diabetes. As there is no evidence from other studies to support an increase in capillary surface area in the forearms of young Type 1 diabetic patients, these results may reflect a primary change in microvascular fluid permeability.

Adolescent↗
PubMed1993

Coming of age with diabetes: patients' views of a clinic for under-25 year olds.

This study is both an evaluation of patients' perceptions of a diabetes clinic for under-25 year olds, and an assessment of experiences in transferring from a paediatric clinic. Sixty-nine patients with Type 1 diabetes (74% of the total clinic), including 41 females, completed evaluations of the clinic and recall of experiences in transfer. Mean age on transferring clinic was 15.9 (range 12-20) years. Paediatricians were perceived to emphasise family and social life, school or work progress; adult physicians tended to stress the risk of long-term complications, importance of exercise and need to maintain strict levels of glycaemic control. Our data suggest that transition to adult care can generally be achieved non-traumatically, but patients may perceive some difficulty because of different emphases and treatment advice favoured by paediatricians and adult physicians.

Adolescent↗
PubMed1993

Effect of an increase in systemic blood pressure on nailfold capillary pressure in humans.

Moderate autoregulation of capillary pressure occurs during changes in arterial and/or venous pressure in animals. Whether an increase in systemic blood pressure is transmitted to capillaries in humans is unknown. Eight healthy volunteers performed isometric handgrip exercise (30% of maximum) while nailfold capillary pressure (CP) and digital arterial blood pressure (DBP) were measured in the contralateral hand. CP was measured for 40 s before exercise and 40-100 s during exercise. Only experiments with no change in pipette position and no artifactual changes in flow were accepted. Basal DBP was stable [91.5 +/- 12.7 mmHg (-40 to -20 s basal) and 91.3 +/- 11.8 mmHg (-20 to 0 s basal)], and isometric exercise increased DBP [100.4 +/- 13.9 mmHg (0-20 s exercise) and 103.1 +/- 15.3 mmHg (20-40 s exercise); P < 0.05]. CP was unchanged during the first 40 s of exercise [18.9 +/- 4.9 mmHg (-40 to 20 s basal), 18.9 +/- 5.2 mmHg (-20 to 0 s basal), 18.4 +/- 4.7 mmHg (0-20 s exercise), and 18.3 +/- 5.3 mmHg (20-40 s exercise)] and remained unchanged for up to 100 s (n = 5), despite a continued elevation of DBP. These data suggest that protective mechanisms minimize the transmission of increases in systemic blood pressure to the capillary bed in humans.

Adult↗
PubMed1992

Relation of skin capillary pressure in patients with insulin-dependent diabetes mellitus to complications and metabolic control.

BACKGROUND: Microvascular disease is a major problem in patients with diabetes mellitus. It has been suggested that diabetic microangiopathy may result from an increase in capillary blood flow and capillary hypertension, but direct evidence of capillary hypertension in such patients is lacking. METHODS: We measured capillary pressure at the summit of the capillary loop by direct microcannulation of skin nail-fold capillaries and a dynamic method of pressure measurement in 29 patients with insulin-dependent (Type I) diabetes and 29 normal subjects matched for age and sex. Among the diabetic patients, 7 had had diabetes for less than one year, 12 had incipient nephropathy (albumin excretion, 20 to 200 micrograms per minute), and 10 had overt nephropathy (albumin excretion, greater than 200 micrograms per minute). In addition, seven patients with no evidence of nephropathy were studied before and after three months of improved glycemic control. RESULTS: The median capillary pressure in the diabetic patients was 20.4 mm Hg (range, 13.6 to 25.3), as compared with 16.7 mm Hg (range, 12.8 to 22.8; P less than 0.001) in the normal subjects. The values were higher in each subgroup of diabetic patients than in the corresponding group of normal subjects, but the values did not differ among the three subgroups of diabetic patients. In the seven patients who were studied before and after three months of improved glycemic control, the median capillary pressure fell from 20.0 mm Hg (range, 18.5 to 21.7) to 17.8 mm Hg (range, 14.1 to 20.3; P = 0.02). CONCLUSIONS: Nail-fold capillary hypertension may develop early in the course of diabetes, before the emergence of microvascular disease, and may be influenced by changes in metabolic control.

Adolescent↗
PubMed1992

Adrenal suppression with intranasal betamethasone drops.

Intranasal betamethasone sodium phosphate drops (Betnesol) are frequently used to relieve nasal congestion due to polyposis. We report a case of significant hypothalamic-pituitary-adrenal suppression secondary to the long-term use of intranasal betamethasone drops. This case emphasizes that the topical application of potent corticosteroids may produce systemic effects.

Administration, Intranasal↗
PubMed1992

Aetiology of diabetic foot ulceration: a role for the microcirculation?

Neuropathy, mechanical stress, and macrovascular disease are involved in the pathogenesis of diabetic foot ulceration. Implicit in the development of gangrene and ulceration is the recognition that these factors interact with the microcirculation, resulting in the failure of skin capillary flow to meet nutritive requirements. There is little evidence to associate structural microangiopathy with foot microcirculatory failure. Significant functional abnormalities of the microcirculation have been defined. In accord with the haemodynamic hypothesis early hyperaemia and capillary hypertension promote more sinister late functional abnormalities with increasing duration of diabetes. These late functional abnormalities include loss of autoregulation and reduced hyperaemic responses which interact with loss of neurogenic flow regulation, disturbed endothelial function, and abnormal rheology to produce the familiar clinical picture of the diabetic foot. Ischaemia secondary to multi-segment arterial disease induces additional abnormalities of microcirculatory function which are superimposed on the pre-existing diabetic microvascular structural and functional microangiopathy.

Diabetic Angiopathies↗
PubMed1992

Quality of life in young adults with type 1 diabetes in relation to demographic and disease variables.

Sixty-nine young adults (mean age 21 (range 15-25) years) with Type 1 diabetes completed measures of diabetes knowledge and quality of life. Factor analysis of the quality of life scale resulted in the identification of three subscales (social relationships, diabetes concerns, and impact). There was no relation between any of the quality of life subscales with knowledge, or with multiple versus twice-daily insulin injection regimens. Higher self-rated diabetes satisfaction was related to lower fructosamine levels and better clinic attendance (p less than 0.05). Females reported a more negative impact of diabetes on their lives compared with males (p less than 0.05).

Adult↗