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Biomedical subjects

P Rasmussen

Publications and source records attributed to P Rasmussen.

At least 127 records · Page 7Linked to original sources

Calcium deficiency, pregnancy, and lactation in rats. Microscopic and microradiographic observations on bones.

Adult female rats were subjected to a calcium-depriving regimen (calcium-deficient diet containing oxalate + pregnancy + lactation) to obtain maximum bone mineral mobilization in as short a time as possible. The femur and tibia were investigated by histological, microradiographic and fluorescent microscopic methods. The regimen caused osteoporosis, which varied in severity with the degree of calcium deprivation. Most of the bone tissue removed was taken from the metaphyseal trabeculae and from the endosteal surface of the diaphysis. The remaining bone tissue seemed unchanged. The cells responsible for the bone removal did not seem to be multinucleated osteoclasts, but mononuclear, hypertrophied, elongated cells, possibly derived from the "resting" osteoblasts normally lining the bony surfaces. No signs of osteocytic osteolysis were observed. Bone formation was reduced, but present even in the most calcium-deprived animals. No increase in the amount of osteoid was observed.

Animals↗

Pituitary-testicular function in acromegalic and hypophysectomized patients.

Serum testosterone, LH, and FSH before and after i.v. injection of LHRH were studied in ten acromegalic men and in twenty-one males after hypophysectomy. Controls were normal men matched according to age. Compared to the controls, basal FSH was slightly higher and basal LGH slightly lower in the untreated acromegalics. The differences were not statistically significant. Serum testosterone and the ratio between basal FSH and LH were significantly lower in the patients. Following hypophysectomy because of acromegaly, the values were essentially unchanged. Hypophysectomy because of a functionless chromophobe adenoma resulted in a significantly lower maximum value of LH but not of FSH after LHRH. The results show that hypogonadism in acromegaly might be a result of imbalance between LH and FSH. They furthermore demonstrate that testing the pituitary-testicular function with LHRH in patients with pituitary disorders seems to be of limited value.

Acromegaly↗

Quantitative observation on teeth during calcium deprivation in rats.

Adult female rats were subjected to severe calcium deprivation by feeding them a calcium-deficient diet containing oxalate (Group A). Furthermore, pregnant and lactating animals were subjected to the same diet (Group B). The mandibular teeth were collected for ash determination and for linear measurements. The ash content of the growing incisors was only slightly reduced in Group A, while the reduction in Group B was 27%. Linear measurements demonstrated that the outer dimensions of the incisors were not affected by the calcium-depriving regimen in either group, while the inner dimensions (pulp cavity) were considerably increased in Group B due to reduced thickness of the dentin mantle. The daily dentin apposition in Group A did not deviate much from the control values, while in Group B it was severely reduced. The thickness of incisor enamel was unaffected by the calcium-depriving regimen. The ash content of the molars was normal in Group A, but slightly reduced in Group B.

Animals↗

Histologic and microradiographic observations on teeth during calcium deprivation in rats.

Adult female rats were subjected to severe calcium deprivation by feeding them a calcium-deficient diet containing oxalate (Group a). Furthermore, pregnant and lactating animals were subjected to the same diet (Group b). The mandibular teeth were examined by histologic, microradiographic and fluorescence microscopic techniques. The incisor enamel was found to be nearly unaffected by the experimental regimen; the dentin formed and mineralized during the experimental period was abnormal only in Group b. Characteristic features were reduced thickness, increased width of predentin and numerous globular defects. Both ameloblasts and odontoblasts were seemingly normal. No obvious differences could be observed between the molars from the controls and the test groups (a,b). "Cementolysis" seemed to be present to the same extent in all groups. In some of the animals of Group b some carious or erosional defects were observed in the molars. These may at least partially account for a small reduction in molar ash content observed in this group.

Animals↗

Effect of thyrotrophin releasing hormone (TRH) in patients with pituitary disorders.

The secretion and biological activity of thyroid stimulating hormone (TSH) were studied in 22 patients with a pituitary tumour (17 acromegalics and 5 patients with a chromophobe adenoma) and in 36 hypophysectomized patients (16 acromegalics and 20 with a chromophobe adenoma). Thyroid function was assessed by serum thyroxine (T4), serum triiodothyronine (T3), and thyroxine-binding globulin (TBG) concentration. Serum TSH was measured before and after injection of TSH releasing hormone (TRH), and in 19 hypophysectomized patients the T3 response after TRH was measured. In addition a TRH test was performed 1-2 weeks after surgery in 11 patients. The basal serum TSH did not differ from euthyroid control values in any of the groups and no late effect of hypophysectomy was observed. Subnormal peak TSH values were seen in 10 out of 37 euthyroid patients, whereas 9 out of 11 hypothyroid patients responded normally. Hypophysectomy caused an immediate but transient decrease in peak TSH in patients with a chromophobe adenoma only. The rise in serum T3 after TRH was significantly lower in hypophysectomized patients than in controls. An increase in TSH was followed by a T3 response in all patients except in 4 out of 8 euthyroid acromegalics. In patients operated on for a chromophobe adenoma the T3 response was correlated with serum T4, whereas this was not the case in acromegalics.

Acromegaly↗

Luteinizing hormone and follicle stimulating hormone and the response to luteinizing hormone releasing hormone in relation to sex and age.

Serum follicle stimulating hormone (FSH) and luteinizing hormone (LH) before and after intravenous injection of luteinizing hormone releasing hormone (LHRH) were studied in 71 male and female subjects of various ages. Mean basal FSH and LH levels were not significantly different in the male groups, except that FSH was significantly higher in the very old subjects. Postmenopausal female subjects had much higher concentrations of both hormones than had premenopausal women. LH was higher in female subjects shortly after the menopause than in very old female subjects. The serum concentrations of both FSH and LH 30 min. after intravenous injection of 200 mug LHRH were not different from the 60 min. values. There was no significant difference in the response of LH in the male groups. The peak FSH concentration was higher in the very old male subjects. Postmenopausal women had a much higher peak concentration of both FSH and LH than had younger subjects. The increment of LH, but not of FSH, was larger in female subjects shortly after the menopause than in very old female subjects. In both sexes there was a significant correlation between the basal FSH/LH ratio and age. In younger male subjects there was a close positive correlation between basal LH and serum testosterone, in older male subjects this correlation was negative and significant.

Adult↗

Short ACTH test in assessing hypothalamic-pituitary-adrenocortical function.

The adrenocortical response to the simple 30-minute ACTH stimulation test was compared with the hypothalamic-pituitary-adrenocortical (HPA) response to insulin-induced hypoglycaemia in 25 patients with various degrees of hypothalamic-pituitary malfunction. The correlations between the increase in plasma cortisol during insulin hypoglycaemia and that during ACTH stimulation (r = 0-66) and between peak plasma cortisol levels during the two tests (r = 0-90) were highly significant. Peak plasma cortisol levels in individual patients were similar on both tests, no patient showing any major discrepancy between the two test results. Thus the simple 30-minute ACTH stimulation test seems to be reliable in detecting imparied HPA function.

Adolescent↗

Endocrine function in patients with suprasellar and hypothalamic tumours.

The pituitary function in 35 consecutive patients with a non-pituitary suprasellar tumour was studied. In craniopharyngiomas and hypothalmic gliomas severe hormonal disturbances were the rule. In suprasellar cysts and meningiomas and in optic nerve gliomas the hormonal disturbances were on the whole less marked and related to the size of the tumour as judged from the pneumoencephalography, larger tumours leading to more extensive alterations than smaller neoplasms.

Adolescent↗

[Milk].

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Animals↗

Ectopic pituitary function.

Two patients with acromegaly have been treated with hypophysectomy. Because the disease was still active, the patients were reoperated. No pituitary tissue could be found at the second operations. Besides the acromegaly, one of the patients had diabetes mellitus (appeared after the first operation), Cushing's syndrome, probably ACTH-dependent, and evidence of thyrotoxicosis. In both patients extopic pituitary tissue was suspected. One of the patients reacted with a normal fall in plasma growth hormone to growth hormone releasing-inhibiting hormone. Ectopic pituitary function should be suspected, if the pituitary function is retained after a hypophysectomy.

Acromegaly↗