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Biomedical subjects

M Rademaker

Publications and source records attributed to M Rademaker.

87 records · Page 5Linked to original sources
PubMed1987

Home monitoring of blood pressure: usefulness as a predictor of persistent hypertension.

We set out to test the hypothesis that home blood pressure reflects "baseline" pressures measured at a general practitioner's surgery or in a hospital outpatient clinic. Twenty patients detected hypertensive during screening in general practice and 30 patients referred to a hospital hypertension clinic for revision of therapy were studied. All were instructed in the use of an electronic semiautomatic sphygmomanometer and measured blood pressure at home for a three day period. Home monitored blood pressure correctly predicted those patients whose diastolic blood pressure fell to below 95 mmHg by the third clinic visit in approximately 90% of all patients. In addition, in those whose blood pressure was high at home it remained so at the clinic or surgery after three visits. These data suggest that home monitoring of blood pressure may be a helpful alternative to repeated clinic visits before embarking on medical therapy.

Blood Pressure Determination↗
PubMed1986

Visceral and skin granuloma annulare, diabetes, and polyendocrine disease.

A middle aged man suffered with insulin dependent diabetes, autoimmune Addison's disease, myxoedema, and severe ulcerative colitis, for which he had undergone subtotal colectomy with formation of an ileostomy. Granuloma annulare confined to the anterior abdominal wall was diagnosed in 1981. In 1983 an episode of severe colicky pain and excessive working of the ileostomy occurred associated with severe hyperglycaemia and increased irritation of the granuloma annulare. Laparotomy disclosed adhesions and numerous white nodules over bowel, mesentery, and peritoneum histologically identical with the skin lesions. Two further episodes of subacute small bowel obstruction occurred, and a repeat laparotomy showed widespread intra-abdominal granuloma annulare. Visceral granuloma annulare appears not to have been reported before, and in this patient exacerbation of the skin lesion was associated with poor diabetic control.

Diabetes Complications↗
PubMed1986

Intravenous captopril treatment in patients with severe cardiac failure.

The effect of intravenous captopril was studied in 26 patients with severe chronic heart failure. Fourteen patients received a 25 mg intravenous bolus dose and 12 patients were given a series of incremental intravenous doses over the range 0.3125-45 mg. After the 25 mg bolus dose there was a rapid reduction in systemic vascular resistance and systemic blood pressure. The effect was greatest five minutes after the dose when cardiac output was increased by 20%. Mean right atrial pressure and pulmonary end diastolic pressure fell more slowly and reached their nadir 60 minutes after administration. Plasma free captopril concentration was significantly correlated with percentage reduction in systemic vascular resistance 15 minutes after the bolus injection, but was not correlated with either changes in right atrial or pulmonary artery pressures. With the series of incremental doses there was a progressive fall in systemic vascular resistance until a cumulative dose of 5.0 mg was reached; beyond this there was no further significant change. The rapid response to intravenous captopril indicates that it may be useful in the treatment of patients with severe heart failure who require intensive treatment. After intravenous injection of captopril haemodynamic responses in patients with heart failure were greatest at plasma concentrations of 100 g/ml to 150 ng/ml. This is considerably higher than the plasma free captopril concentrations found after conventional oral doses of captopril.

Adult↗
PubMed1985

Target-like skin lesions in primary amyloidosis.

A case of primary amyloidosis is described, during the course of which transient, purpuric haloes appeared around long-standing Campbell de Morgan spots, forming target-like lesions of the skin.

Aged↗
PubMed1985

Reliability of the evoked response in determining the paced ventricular rate and performance of the QT or rate responsive (TX) pacemaker.

The TX pacemaker uses a conventional transvenous electrode to sense T-waves of paced ventricular complexes and it adapts the pacing rate to varying physiological demands by responding to changes in the QT or, more correctly, the stimulus artifact-to-T-wave (stimulus-T) interval. This pacing system was assessed in 13 patients. The relation between heart rate and stimulus-T interval and the effect of programming on the performance of this pacemaker were studied on several occasions in each patient. Treadmill exercise performance during TX pacing mode was compared with atrial synchronized ventricular (VAT) and asynchronous ventricular demand (VOO and VVI--70 beats per minute) pacing modes. T-wave sensing problems arose in three patients. In one, this was overcome by reducing the pulse amplitude from 5.0 to 2.5 V. In another patient, spontaneous recovery of T-wave sensing occurred 5 months after pacemaker implantation. T-wave sensing deteriorated with the passage of time in most patients. Satisfactory rate response as assessed by treadmill exercise testing and Holter monitoring was achieved in 12 patients through adjustments of two programmable parameters: the slope that defines the alteration in heart rate in response to a millisecond change in stimulus-T interval and the "sensing window" that is the interval during which T-waves can be sensed and a rate response is possible. Exercise performance was significantly better during rate responsive pacing (TX) mode as compared with VVI pacing but was comparable to that during VAT pacing. The resting heart rate/stimulus-T interval can be described by the following linear regression equation: stimulus-T interval = 466 - 1.68 X paced-rate, r2 = -0.62. This relation, however, was subject to wide inter- and intra-patient variation. Consequently, given identical programmed parameters and exercise protocol, the chronotropic response differed significantly from patient to patient and in the same patient from one occasion to another. Our results show that a physiologically beneficial chronotropic response can be achieved in most patients. However, reprogramming, based on results of exercise tests and Holter monitoring, may be necessary to adjust for changes in T-wave sensing and the heart rate/stimulus-T interval relation and, thus to ensure that the pacemaker continues to function optimally.

Adolescent↗
PubMed1985

Plasma free captopril concentrations during short and long term treatment with oral captopril for heart failure.

Plasma free captopril concentrations and haemodynamic response to captopril were studied in 20 patients with severe chronic heart failure. A 25 mg oral dose of captopril produced a 36% reduction in systemic vascular resistance, with individual responses varying from 13% to 64%. Mean systemic pressure fell by 20% and cardiac output rose 28%. The absorption of captopril was rapid. Peak plasma free captopril concentration occurred at 45 minutes after the dose and was followed by a smaller second peak. Peak plasma free captopril concentrations varied more than 20-fold but did not correlate with the maximal reduction in systemic vascular resistance. Elimination half life was seven hours. Fourteen patients were restudied after 1-2 months of captopril treatment and 12 showed symptomatic benefit. There was a sustained improvement in haemodynamic state and in non-invasive indices of myocardial function. During long term treatment the predose plasma free captopril concentration correlated well with dosage, but steady state captopril concentrations did not show a significant relation with haemodynamic response. On a dosage regimen of 25-50 mg three times daily the morning predose plasma free captopril concentration and plasma renin activity were relatively low and suggested that maximal inhibition of the renin-angiotensin system was not maintained throughout the dosage interval.

Aged↗
PubMed1985

Inhibition of the renin-angiotensin-aldosterone axis by low dose intravenous captopril as a treatment for accelerated phase hypertension.

A parenteral preparation of captopril has been used to produce a smooth reduction of blood pressure in patients presenting with accelerated phase hypertension. In five out of six patients studied, an intravenous infusion of captopril at dose rates ranging from 250-2000 micrograms/h lowered blood pressure from 199 +/- 13/115 +/- 5 to 143 +/- 14/86 +/- 5 mmHg over several hours without adverse effects. Partial inhibition of the angiotensin converting enzyme was demonstrated by a rise in plasma renin activity (PRA) and a fall (although not to normal) in elevated levels of angiotensin II and aldosterone. The plasma level of free captopril at the point of blood pressure control was 15 +/- 4 ng/ml and its short effective half-life was demonstrated by a rise in blood pressure within 15 minutes of stopping the infusion. These data demonstrate that very small amounts of captopril can produce a dose-dependent inhibition of angiotensin converting enzyme without abrupt changes in blood pressure.

Adult↗
PubMedDate not supplied

The anti-platelet effect of nifedipine in patients with systemic sclerosis.

The enhanced platelet reactivity and impaired thrombolysis in patients with systemic sclerosis may contribute to the microvascular insufficiency seen in this disease. Anti-platelet therapy has therefore been suggested for the treatment of Raynaud's phenomenon secondary to systemic sclerosis. Using a novel technique, the Haemostatometer, haemostasis (shear-induced) and thrombolysis (dislodgement of the haemostatic plug) were assessed initially in 15 patients with systemic sclerosis before and 90 minutes after a single oral dose of nifedipine (10 mg), and then at 4-week intervals for 16 weeks in 10 patients on long-term nifedipine (10-20 mg tid). Ninety minutes after a single oral dose of nifedipine in 15 patients with systemic sclerosis, haemostasis was significantly prolonged from 140 +/- 12 sec to 178 +/- 21 sec (mean +/- SE, p less than 0.005). The time until spontaneous thrombolysis occurred was significantly shortened following nifedipine, from an abnormal time of 57.8 +/- 2.8 min to a more normal value of 34.0 +/- 5.1 min (mean +/- SE, p less than 0.01). This improvement in haemostasis and thrombolysis was maintained through 16 weeks on longterm nifedipine treatment. These findings suggest that nifedipine may reduce the risk of developing multiple thrombo-emboli in patients with systemic sclerosis.

Administration, Oral↗
PubMedDate not supplied

Calcium influx into red blood cells: the effect of sera from patients with systemic sclerosis.

The rheology of red blood cells in patients with systemic sclerosis is abnormal. To investigate this further we have examined the effect of sera from patients with systemic sclerosis on the handling of calcium ions by the erythrocyte membrane. Normal erythrocytes were filled with a photoprotein (aequorin) which emits light on contact with calcium. These photoprotein loaded normal erythrocytes were then incubated overnight with serum from: normal subjects (n = 20), from patients with systemic sclerosis (n = 27) or from patients with primary Raynaud's disease (n = 10). There was no significant difference in basal calcium leakage, as measured by the amount of light produced following the addition of triton X-100. Induced calcium influx, as measured by the amount of light produced following the addition of ionophore A23817, was significantly greater in the photoprotein loaded erythrocytes incubated overnight with serum from patients with systemic sclerosis compared to those incubated with serum from normal subjects (p less than 0.02) or patients with primary Raynaud's disease (p less than 0.01). This modulation of Ca2+ handling in erythrocytes by a serum factor from patients with systemic sclerosis could account for the alterations in erythrocyte function, such as red cell deformability, observed in systemic sclerosis.

Adult↗