Search PubMed⌕ Search

Biomedical subjects

R Pelkonen

Publications and source records attributed to R Pelkonen.

At least 19 recordsLinked to original sources
PubMed1992

Cyclosporin reduces renal prostanoid excretion in type 1 diabetic patients.

Prostacyclin and thromboxane A2 are important regulators of kidney blood flow. To examine whether changes in their metabolism could be involved in the nephrotoxicity of cyclosporin, we determined urinary excretion of 6-keto PGF1a and dinor-6-keto PGF1a (prostacyclin metabolites) and dinor-TxB2 (thromboxane metabolite) in five newly diagnosed type 1 diabetic patients during and after stopping cyclosporin therapy. In the resting state, cyclosporin had no effect on prostanoid excretion. In response to exercise, urinary excretion of 6-keto PGF1a was reduced by 50% (P less than 0.02), dinor-6-keto PGF1a by 15% (P less than 0.05) and dinor-TxB2 by 45% (P less than 0.02), while albumin excretion increased 4.5-fold (P less than 0.05) during cyclosporin therapy. Simultaneously, there was a rise in serum creatinine concentration, and renal biopsy specimens obtained from three patients showed periglomerular and interstitial fibrosis and tubular atrophy. After the discontinuation of cyclosporin therapy, serum creatinine concentrations returned to normal, histological changes improved and there was an associated rise in urinary prostanoid excretion. These data suggest that a reduction in renal prostanoid synthesis by cyclosporin may diminish renal blood flow and function, and lead to histological changes in the kidney.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

Normal renal sensitivity to atrial natriuretic peptide in Gordon's syndrome.

To test the hypothesis that renal sensitivity to atrial natriuretic peptide (ANP) is impaired in Gordon's syndrome (hypertension and hyperkalaemia with normal glomerular filtration rate) we infused alpha-hANP into two patients with this syndrome (a sister and a brother, 19 and 18 years of age). For comparison, 11 healthy volunteers were also examined. The infusion of alpha-hANP increased urinary volume and excretion of sodium similarly in the patients and controls. The excretion of potassium did not change in either the patients or the controls. The infusion of alpha-hANP had no effect on the serum potassium levels or the plasma CO2 content in the patients. The present results do not confirm the hypothesis of lack of sensitivity to ANP as a pathophysiological concept in Gordon's syndrome.

Adolescent↗
PubMed1992

Fuel and fluid homeostasis during long-term exercise in healthy subjects and type I diabetic patients.

OBJECTIVE: This study was designed to examine metabolic and hormonal effects of long-term exercise in healthy subjects and insulin-dependent (type I) diabetic patients. RESEARCH DESIGN AND METHODS: Two studies were performed. First, 16 healthy males (32 +/- 3 yr) were studied during a semitriathlon competition (2 km swimming, 90 km biking, and 21 km running). Second, 9 type I diabetic males (41 +/- 2 yr) and 17 healthy matched control subjects were studied during a 75 km cross-country skiing race. Blood samples were taken before and immediately after exercise, and also during the ski race. RESULTS: During the semitriathlon race, serum insulin, C-peptide, glucagon cortisol, growth hormone ACTH, prolactin, and plasma renin activity increased two- to ninefold, whereas serum testosterone fell. Apart from a fall in magnesium, serum electrolyte concentrations remained unchanged. Before long-term skiing, patients reduced their insulin dose by 30-40%. They were hyperglycemic during the initial part of the race, but near normoglycemic thereafter. There were large interindividual variations in the increments of counterregulatory hormones, whereas serum testosterone and luteinizing hormone fell quite uniformly. Plasma renin activity and aldosterone concentrations rose similarly in diabetic and healthy subjects, whereas the rise in antidiuretic hormone was slightly greater in diabetic patients. During the initial part of the race, serum atrial natriuretic peptide fell in both groups. CONCLUSIONS: Severalfold increments in hormone concentrations contribute to the maintenance of fuel and fluid homeostasis during long-term exercise. With an appropriate adjustment of insulin dose and diet, also type I diabetic patients can participate in competitive long-term exercise.

Adult↗
PubMed1991

Is the treatment of metastatic carcinoid tumor with interferon not as successful as suggested?

Eight patients with metastatic carcinoid tumor, seven of whom had symptoms of the carcinoid syndrome, were treated with either human leukocyte interferon (seven patients) or recombinant alpha-interferon (IFN alpha-2b) (one patient) at doses of 4.5 to 21 x 10(6) IU weekly for 1 to 21 (mean, 8.5) months. Tumor regression on computed tomography (CT) scan was found in one patient, the CT findings remained unchanged in three, and the tumor progressed in four patients. A clearcut and continuing decrease in urinary levels of 5-hydroxyindoleacetic acid (5-HIAA) was observed in one patient and a transient one in four patients. The symptoms improved in only two of seven patients. Four patients had leukopenia develop, which was circumvented by reducing the dose. The authors conclude that interferon therapy of the carcinoid tumor is not as successful as has been suggested in previous reports.

Adult↗
PubMed1991

Testosterone-secreting virilizing adrenal adenoma with human chorionic gonadotrophin receptors and 21-hydroxylase deficiency.

A 60-year-old woman was evaluated for persistently elevated serum testosterone concentrations after bilateral ovariectomy. Her serum cortisol, androstenedione, dehydroepiandrosterone sulphate and 17-hydroxyprogesterone levels were normal, and decreased after dexamethasone administration. Those of testosterone (17.8-18.4 nmol/l) were remarkably high (normal range 0.7-2.8 nmol/l), were not suppressed by dexamethasone, but clearly increased after hCG administration (up to 128 nmol/l). Computed tomography revealed an adenoma in the right adrenal gland and adrenal scintigraphy under dexamethasone suppression visualized this adenoma. A right adrenalectomy was performed. (1) The tumour was histologically and ultrastructurally adrenocortical adenoma of zona reticularis cell type. (2) The adenoma tissue contained hCG receptors (198 fmol/g). (3) During tissue culture both ACTH and hCG were capable of maintaining its testosterone production, which was attenuated with time without stimulation. (4) The adenoma tissue did not elaborate 21-hydroxylated steroids in contrast to normal adrenal tissue. Thus the aberrant endocrine behaviour of this gonadotrophin-responsive testosterone-secreting adenoma of adrenal zona reticularis cell origin can be explained by ectopic functional hCG receptors and the lack of 21-hydroxylase activity.

Adenoma↗
PubMed1991

Obstructive sleep apnoea syndrome in morbidly obese patients.

Twenty-seven morbidly obese patients (13 men and 14 women) with body mass index greater than or equal to 40 kg m-2 were examined. The mean age of the subjects was 36.9 +/- 8.2 years (range 23-51 years), and the mean BMI was 50.2 +/- 6.2 kg m-2 (range 40.0-62.9 kg m-2). A whole-night sleep recording was made for all patients with signs or symptoms indicative of possible obstructive sleep apnoea syndrome (OSAS). If the first nocturnal sleep recording was abnormal, it was controlled after 1 year. Eleven (10 men and one woman) of the 27 patients had an oxygen desaturation index (ODI) of 10 h-1. They were symptomatic with excessive daytime sleepiness or other daytime symptoms of OSAS. The occurrence of OSAS in men and women was 76.9 and 7.1%, respectively. Arterial hypertension was associated with OSAS, but not with smoking or the degree of obesity. Antihypertensive treatment was received by nine of the 27 patients; six of them had OSAS. Thus six of the 11 (54.5%) patients with OSAS and three of the 16 (18.8%) nonapnoeic patients were treated for arterial hypertension (Fisher exact test, P = 0.042). The odds ratio of OSAS for arterial hypertension is 5.2 (95% CI, 0.71-43.6). Vertical-banded gastroplasty was performed in 14 patients, three of whom had OSAS. The selection of patients for gastroplasty was made without taking into account the results of sleep recordings. In the three OSAS patients, a 30-38% reduction in BMI was achieved by surgery. Eight patients with OSAS were treated with an intensified dietary regimen, and the reduction in BMI ranged from -2.6 to 33%. OSAS was either cured or significantly improved in six (55%) patients, with a mean reduction in BMI of 27%, while in patients with persistent OSAS the mean reduction in BMI was only 7%.

Adult↗
PubMed1991

Hormonal changes in severely uncontrolled type 1 (insulin-dependent) diabetes mellitus.

To investigate endocrinological changes associated with severely uncontrolled type 1 (insulin-dependent) diabetes mellitus 27 patients (19 men, eight women) with ketoacidosis or severe ketonuria (= group 1) were examined on admission and after recovery. For comparison 13 non-ketotic patients (seven men, six women), admitted for adjustment of treatment because of poor diabetic control (= group 2), and 20 healthy controls were studied. On admission, the serum testosterone levels in men were lower in group 1 (15.1 +/- 2.0 nmol l-1) (mean +/- SEM) than in group 2 (27.2 +/- 2.8 nmol l-1) (p less than 0.01) and healthy controls (20.6 +/- 2.0 nmol l-1) (p less than 0.05). During treatment the testosterone levels in group 1 rapidly rose to the control level. The serum oestradiol levels in women were low in group 1 both on admission and discharge. The serum prolactin levels were low in female patients in group 1 (119 +/- 17 mIU l-1) compared with the women in group 2 (315 +/- 75 mIU l-1) (p less than 0.05). On admission the serum cortisol levels were higher and their response to 1 mg of dexamethasone was weaker in group 1 than in group 2 and healthy controls. After recovery the serum cortisol levels fell by 15% (p less than 0.01) and the response to 1 mg of dexamethasone returned to normal in group 1. In group 1 during treatment the serum free T4 and reverse T3 levels fell, and the T3 levels rose, whereas the thyroid stimulating hormone (TSH) levels and their responses to TRH remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Pituitary-gonadal hormones and adrenal androgens in non-cirrhotic female alcoholics after cessation of alcohol intake.

To investigate the sex-hormone profiles associated with chronic alcoholism in women we examined 16 non-cirrhotic alcohol abusers (aged 18-46 years). They were admitted for the treatment of alcoholism (duration of 2-16 yrs) to a social hospital for 6 weeks. Their mean daily alcohol consumption was 170 g. Blood samples for serum LH, FSH, prolactin (PRL), oestrone (E1), oestradiol (E2), progesterone (P), 17-alpha-hydroxyprogesterone (17-OHP), androstenedione (A) and dehydroepiandrosterone (DHEA) were drawn three times a week during the hospital stay. Similar blood samples were taken from 10 control women during one menstrual cycle. The cycles were anovulatory in two patients and in none of controls. Serum LH and FSH levels were similar in alcoholic and control women but serum concentrations of PRL were increased 2-4-fold in alcoholic women. In the patients serum, concentrations of E1 and E2 tended to be lower during the follicular and midcycle phases, as did those of P and 17-OHP during the luteal phase. Compared with the controls, serum levels of A were increased 2-3-fold in the patients. A parallel difference between the two groups was seen in serum DHEA concentrations. We conclude that until liver injury, even heavy alcohol drinking has only minor effects on the secretion of gonadotrophins and ovarian steroids. Hypersecretion of PRL and adrenal androgens may well be an initiating mechanism for sexual dysfunction of female alcoholics.

Adolescent↗
PubMed1978

Pituitary function after pituitary apoplexy.

Pituitary function was studied in nine patients who had recovered from pituitary apoplexy. All the patients recovered spontaneously; none required immediate surgery. Four of the patients had acromegaly, two had pituitary-dependent Cushing's syndrome, and a "functionless" pituitary adenoma was found in three. Low serum growth hormone concentrations were observed in three patients with acromegaly whereas the concentration remained increased in the fourth one. Of the two patients with Cushing's syndrome, a selective ACTH-deficiency developed in one and Nelson's syndrome appeared with excessive secretion of ACTH in the other. Transient or persistent hypofunction of the anterior pituitary occurred in al patients. Three patients underwent hypophysectomy after respective intervals of three, eight and 12 months after pituitary apoplex. The operation revealed a hemorrhage in one functionless adenoma and a large cyst in another one. In the third patient who had acromegaly, no signs of the pituitary apoplexy were observed at operation.

Acromegaly↗
PubMed1978

Somatostatin inhibits the pentagastrin-induced release of serum calcitonin in medullary carcinoma of the thyroid.

The effect of somatostatin on the secretion of calcitonin was studied in four patients with medullary carcinoma of the thyroid (MCT). The basal serum calcitonin level was markedly elevated in all cases. A bolus injection (100 microgram) of somatostatin followed by an intravenous infusion (5 microgram/min) for 60 min suppressed the basal calcitonin level in three of the four patients by 24-42%, while it had no inhibitory effect in one case. In another experiment, the pentagastrin-stimulated (6 microgram/kg s.c.) calcitonin release was partially blocked by a simultaneous i.v. injection of somatostatin (200 microgram) in all four patients studied. These experiments add human calcitonin to the list of hormones whose release in inhibited by somatostatin.

Adult↗
PubMed1978

Ultrastructural and steroidogenic characteristics of an androgen-producing adrenocortical tumour.

A 16-year-old female patient with an adrenal tumour was studied. Clinically she had progressive hirsutism, showed high urinary 17-oxosteroid excretion with normal plasma cortisol. Plasma C19-steroids, both unconjugated (including testosterone) and sulphate-conjugated, were greatly elevated. On surgical exploration an adrenal tumour was histologically an adenoma. On ultrastructural analysis the cells in all zones of the adjoining adrenal were considered normal. Although the tumour cells had the general appearance of a steroid-secreting cell their structure diverged from the cells of every subzone of the cortex. This was the case particularly with mitochondria and lipid inclusions. The only endogenous unconjugated steroids detected in the adjoining cortex were corticosterone and cortisol while in tumour tissue these were present in lesser amounts. The tumour tissue contained large amounts of C19-steroids, 11beta-hydroxy-androstenedione being quantitatively most significant. On the basis of the steroid profile an impaired defect of 21-hydroxylation in tumour cells leading steroid synthesis from corticosteroidogenesis to the C19 pathway is proposed.

Adenoma↗