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J Freijanes

Publications and source records attributed to J Freijanes.

13 recordsLinked to original sources
PubMed1993

1,25-Dihydroxyvitamin D3 receptors in peripheral blood mononuclear cells from patients with postmenopausal osteoporosis.

A decrease in intestinal calcium absorption, in spite of normal serum calcitriol levels, has been reported in postmenopausal osteoporotic women, raising the possibility of an intestinal resistance to the hormone. The mechanism responsible for it could lie at the receptor or postreceptor level. Intestinal receptors are difficult to study on clinical settings, but calcitriol receptors have been found in peripheral blood mononuclear cells (PBMC). We have studied the PBMC calcitriol receptors by means of Scatchard analysis in 11 postmenopausal osteoporotic women without any treatment and in 12 normal postmenopausal women of similar age. No differences were found in the dissociation constant (Kd) or the concentration of binding sites (Nmax) (Kd in patients: 0.90 +/- 0.75 x 10(-10) M; Kd in controls: 0.85 +/- 0.40 x 10(-10) M; Nmax in patients: 2.4 +/- 1.2 fmol/10(7) cells; Nmax in controls: 2.1 +/- 0.6 fmol/10(7) cells), supporting the contention that the disorder responsible for the resistance to calcitriol in postmenopausal osteoporotic women is located at the postreceptor level. In addition, our study included five postmenopausal osteoporotic women treated with calcitriol (0.5 microgram/day). The number of calcitriol receptors was increased in this group (Nmax: 3.9 +/- 2.0 fmol/10(7) cells vs. 2.1 +/- 0.6 fmol/10(7) cells; P = 0.02).

Adult↗
PubMed1993

Lack of effect of octreotide on parathyroid hormone levels and urinary excretion of epidermal growth factor.

To determine whether octreotide may acutely modify calcium homeostasis and/or inhibit the EGF production by the kidney, a subcutaneous injection of octreotide (100 micrograms) was administered to ten healthy volunteers. Blood and urine samples were collected at -30, 0, 60, 90, 120 and 180 minutes. Serum insulin, intact PTH, osteocalcin, total and ionized calcium and urinary EGF and creatinine were measured. There was no modification in serum PTH, osteocalcin and total or ionized calcium. There was no significant modification of urinary EGF, although a trend to decrease was evidenced.

Adult↗
PubMed1991

Vitamin D metabolism and serum binding proteins in anorexia nervosa.

Serum vitamin D metabolites and other parameters of mineral metabolism were measured in 12 patients with anorexia nervosa. Serum concentrations of calcium, phosphate, albumin, alkaline phosphatase, parathyroid hormone, calcitonin, osteocalcin, and 24-hours calcium excretion were normal. Serum 25-hydroxyvitamin D (25OHD) concentration was similar in patients and normal subjects, whereas 1,25-dihydroxyvitamin D (1,25(OH)2D) levels were significantly reduced in patients (62 +/- 17 vs 82 +/- 17 pmol/l); p less than 0.05). The concentration of vitamin D-binding protein (DBP) in patients was normal, but serum binding capacity (Nmax) was diminished in anorectic patients (2.05 +/- 0.50 vs 2.53 +/- 0.51 mumol/l; p less than 0.05). The diminished serum binding capacity, in spite of normal concentrations of albumin and DBP, reflects the presence of qualitative rather than quantitative defects in serum transport proteins. Since the reduction in 1,25(OH)2D and serum binding capacity was quantitatively similar, it is likely that free 1,25(OH)2D levels would be normal.

Adolescent↗
PubMed1990

[Different behavior of bone turnover markers in endocrine (extrinsic) and structural (intrinsic) osteopathies].

Alkaline phosphatase, osteocalcin and hydroxyproline levels were evaluated in patients with the following conditions: primary hyperparathyroidism, renal dialysis, hyperthyroidism, Cushing's syndrome, long term corticosteroid therapy, Paget's disease, osteoblastic metastases, osteolytic or mixed metastases, and nutritional osteomalacia. In all cases the levels of the three substances were increased, with the following exceptions: a) in endogenous or exogenous hypercortisolism states osteocalcin level was reduced and those of alkaline phosphatase and hydroxyproline were unchanged; and b) in blastic or lytic metastases osteocalcin level was unchanged. In general, alkaline phosphatase and hydroxyproline levels had a higher sensitivity than those of osteocalcin in structural bone disease (Paget's disease, blastic or lytic metastases), whereas the converse was true for endocrine bone disease (the remaining conditions except osteomalacia, which is mixed, both structural and endocrine; in this syndrome, the three substances showed the same sensitivity.

Adolescent↗
PubMed1990

Successful treatment with ketoconazole of Cushing's syndrome in pregnancy.

Patients with Cushing's syndrome rarely become pregnant. This is a high risk situation both for the fetus and the mother, if untreated. We report a patient with Cushing's syndrome due to adrenocortical adenoma who became pregnant and was successfully treated with ketoconazole during the last period of pregnancy.

Adenoma↗
PubMed1989

[Effect of active metabolites of vitamin D on manifestations of primary hyperparathyroidism].

We have evaluated the serum levels of 25-hydroxyvitamin D (25-OHD) and 1,25-dihydroxyvitamin D (1.25-OHD) in 33 patients with primary hyperparathyroidism and normal renal function, relating them with the clinical expression of the disease and other biochemical parameters. The level of 1.25-OHD of the patients was significantly higher than in healthy controls [51 +/- 18 vs 36 +/- 10 pg/ml (122 +/- 43 vs 86 +/- 24 pmol/l), p less than 0.001], although it was higher than the upper limit of the normal range in only 36% of patients. By contrast, the level of 25-OHD was diminished [11.0 +/- 6.3 ng/ml (27.5 +/- 15.7 nmol/l) in the patients and 19.9 +/- 10.5 ng/ml (49.7 +/- 26.2 nmol/l) in the controls, p less than 0.01]. A positive correlation was found between PTH and 1.25-OHD (r = 0.40, p less than 0.05) and a negative one between PTH and 25-OHD (r = -0.40, p less than 0.05). Calcemia was correlated with PTH (r = 0.77, less than p 0.001) but not with 1.25-OHD (partial r = 0.22). There was no correlation between vitamin D metabolites and calciuria, nor between the former and the biochemical indexes of bone remodelling. There were no significant biochemical differences between patients with renal calculi and those without them. It was concluded that PTH level appears as the major determinant factor of 1.25-OHD serum level. The serum level of vitamin D metabolites does not seem to clearly influence calcemia, calciuria, bone remodelling or the development of calculi.

Adult↗
PubMed1987

No effect of verapamil on calcium stimulated calcitonin release.

We investigated the effect of infusing 5 mg/h of verapamil on calcitonin release in normal males. After 60 minutes of infusion, ionized calcium and calcitonin levels were unchanged. At 60 minutes we infused 3 mg/kg of body weight of elemental calcium over 10 minutes and we found that calcitonin release was no different from when the subjects were receiving verapamil. These results suggest that, despite blocking calcium channels, acute hypercalcaemia produces normal calcitonin release.

Adult↗
PubMed1987

Vertebral compression fractures and mineral metabolism in chronic obstructive lung disease.

Chronic obstructive lung disease has been reported as a cause of osteoporosis, though whether this association is due to the disease itself or to corticosteroid treatment has not been elucidated. We studied 44 male patients with chronic obstructive lung disease (mean (SD) FEV1 39% (14%) of predicted normal) who were not having long term corticosteroids. No differences in a vertebral deformity score or in metacarpal index were found between them and a control group of similar age. Indices of bone formation (serum osteocalcin) and bone resorption (urinary hydroxyproline) were normal and parathyroid hormone and 1,25-dihydroxyvitamin D were also normal. Serum 25-hydroxyvitamin D was decreased, indicating depleted vitamin D. Calcitonin concentrations were higher in the patient than in the control group of the same age. There was no increase in the prevalence of osteoporosis in patients with chronic obstructive lung disease who had not received long term corticosteroid treatment. Increased concentrations of calcitonin may protect the skeleton from the detrimental effect of hypovitaminosis D.

Bone and Bones↗
PubMed1982

Familial cerebellar ataxia and hypogonadotropic hypogonadism: evidence for hypothalamic LHRH deficiency.

A family with familial cerebellar ataxia and hypogonadotropic hypogonadism is described. The condition was inherited as an autosomal recessive defect. CT scan in one case revealed cerebellar and brain stem atrophy. Endocrinological tests showed abnormalities only in two patients who were clinically affected. In both cases raised gonadotropic levels were found after repetitive stimulation with luteining hormone-releasing hormone which suggests that the hypogonadism was due to a primary hypothalamic disturbance.

Adult↗