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Biomedical subjects

I L Nilsson

Publications and source records attributed to I L Nilsson.

4 recordsLinked to original sources
PubMed2001

Endothelial vasodilatory function and blood pressure response to local and systemic hypercalcemia.

BACKGROUND: Endothelial vasodilatory dysfunction occurs in primary hyperparathyroidism. Mechanistically it could be a sign of atherosclerosis, but improvement after parathyroidectomy suggests coupling to hypercalcemia and increased parathyroid hormone levels of patients. METHOD: A total of 12 volunteers underwent forearm venous occlusion plethysmography with systemic (intravenous) and local (brachial artery) infusion of calcium. Endothelium-dependent and endothelium-independent vasodilations were evaluated at stable hypercalcemia through infusion of methacholine and nitroprusside into the brachial artery, and an endothelial function index was calculated as the ratio between them. RESULTS: Normal ionized blood calcium values rose 0.24 +/- 0.09 mmol/L in the cubital venous blood during local calcium infusion and 0.32 +/- 0.16 mmol/L during the systemic infusion. The systemic infusion raised systolic blood pressure (114 +/- 13 to 121 +/- 10 mm Hg; P < .05). It decreased the function index (1.28 +/- 0.40 to 1.00 +/- 0.14; P < .05; n = 11) due to an elevated endothelium-independent vasodilation (EIDV) (P < .05), despite the fact that serum parathyroid hormone values decreased (P< .01). A similar trend in vasodilatory responses was seen during local calcium infusion when the function index correlated inversely to the local blood calcium (r = -0.58, P < .05; n = 12). CONCLUSIONS: Acute hypercalcemia results in dose-related impairment in endothelial vasodilatory function and increased systolic blood pressure. This substantiates the importance of hypercalcemia for cardiovascular complications and prospects for normalization by active treatment in primary hyperparathyroidism.

Adult↗
PubMed2000

Left ventricular systolic and diastolic function and exercise testing in primary hyperparathyroidism-effects of parathyroidectomy.

BACKGROUND: Nontraditional manifestations of primary hyperparathyroidism (HPT) are controversial and may include morbidity, mortality, and risk factors for cardiovascular diseases. This study evaluates cardiovascular functions at rest and during exercise in HPT. METHOD: Thirty patients with HPT (mean serum calcium, 2.97 +/- 0.24 mmol/L) and 30 control people with normocalcemia, matched for age and sex, underwent symptom-limited exercise testing and echocardiography before and 13 months (mean) after having a parathyroidectomy. RESULTS: Despite similar maximal workload and blood pressures at rest in patients and healthy controls, HPT associated with higher systolic blood pressure during exercise (P =.03) and increased number of ventricular extrasystolic beats (P =.04). There was also an operatively reversible increase in ST-segment depression during exercise. Echocardiography showed an increased left ventricular (LV) isovolemic relaxation time (P =.02) and mitral deceleration time (P =.08), which indicate an LV diastolic dysfunction that could be partially reversed by operation. LV systolic function (ejection fraction and shortening fraction) tended to be elevated in HPT (P =.07 and.06, respectively) and diminished after parathyroidectomy. There was a trend toward higher LV mass, especially among the men with HPT (P =.06), which was unchanged postoperatively. CONCLUSIONS: HPT couples to reversible signs of myocardial ischemia and LV dysfunctions with a possible increased risk of life-threatening arrhythmia.

Adult↗
PubMed1999

Endothelial vasodilatory dysfunction in primary hyperparathyroidism is reversed after parathyroidectomy.

BACKGROUND: Primary hyperparathyroidism (HPT) is accompanied by hypertension and a cardiovascular mortality. Impaired endothelium-dependent vasodilatation (EDV) occurs in hypertension but has not been fully investigated in HPT despite the vasoactive influences of parathyroid hormone. METHODS: Twenty-five HPT patients and 25 normocalcemic control subjects, matched for age and gender, underwent forearm venous occlusion plethysmography. EDV and endothelium-independent vasodilatation (EIDV) were evaluated during local infusion of metacholine (2 and 4 micrograms/min) and nitroprusside (5 and 10 micrograms/min), respectively. The endothelial function index was calculated as the ratio of forearm blood flows during the high doses of metacholine and nitroprusside. Ambulatory 24-hour blood pressures and thickness of the intima-media complex of the carotid arteries were also measured; the latter is considered an early marker of atherosclerosis. RESULTS: Endothelial function index was lower in the HPT patients compared with control subjects (1.01 +/- 0.26 vs 1.27 +/- 0.31, P = .003). Reinvestigation 10 months after parathyroidectomy showed normalization of the index (1.31 +/- 0.39, P = .01) due to a numeric increase in EDV and decrease in EIDV. The carotid intima-media thickness and blood pressure were similar in the groups and unaltered postoperatively. CONCLUSIONS: Endothelial vasodilatory dysfunction is another indicator of the vascular disturbance of HPT and can be normalized by parathyroidectomy.

Aged↗