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Biomedical subjects

F Bigi

Publications and source records attributed to F Bigi.

49 records · Page 3Linked to original sources

Recurrent hyperparathyroidism: a study of 3 cases with evaluation of some pathogenetic and clinical aspects.

Three patients with recurrent hyperparathyroidism (15, 8 and 3 years respectively, after the first operation) are described in order to establish the causes and define the clinical characteristics of the disease. The observation that in the present series recurrent hyperparathyroidism was associated either with an adenoma (two cases) or a carcinoma (one case), appears to stress the possibility of the pathological involvement of one gland even though recurrent hyperparathyroidism should be considered due to the chronic extrinsic stimulation of the parathyroid glands. The severity of the clinical and metabolic picture observed at the time of the first diagnosis and/or at the time of recurrence together with the simultaneous presence of bone and stone disease in the patients described is of particular interest. The cases reported underline the importance of carrying out careful metabolic investigations in patients with hyperparathyroidism not only before but also for a prolonged period of time after operation.

Adenoma↗

Normal calcitonin secretion in acromegaly.

Calcium and phosphate metabolism has been studied in eight patients with active acromegaly. Plasma calcium, phosphate, alkaline phosphatase, creatinine and parathyroid hormone levels were in the normal range in all patients, while urinary calcium excretion, calcium/creatinine ratio and hydroxyproline were higher than in controls (p less than 0.01, p less than 0.01, p less than 0.02, respectively). Basal plasma calcitonin levels were in the normal range and stimulation with calcium (3 mg/kg body weight in 10 min) showed similar calcitonin responses in acromegalic and normal subjects. Our data show that in normocalcemic acromegaly with high bone turnover calcitonin secretion is not abnormal.

Acromegaly↗

Basal and stimulated calcitonin secretion in primary hyperparathyroidism before and after parathyroidectomy.

To investigate calcitonin secretion in primary hyperparathyroidism, basal and stimulated (3 mg Ca++/kg body weight/10 min) immunoreactive calcitonin plasma levels were studied before parathyroidectomy. Plasma calcitonin levels were raised in 50% of patients regardless of sex, but a significant correlation between basal plasma calcium and calcitonin was found only in males. A reduced calcitonin response to calcium infusion was observed in all patients. Parathyroidectomy invariably induced a normalization of calcitonin basal levels. Our findings confirm the existence of a decreased parafollicular cell reserve probably as a consequence of the persistent hypercalcemic state in hyperparathyroid patients and suggest that it is more frequent in females.

Adult↗

Changes in mineral content and biochemical bone markers at the menopause.

Serum alkaline phosphatase activity, serum bone gamma-carboxyglutamic acid protein, urinary hydroxyproline and bone mineral content were simultaneously measured in 30 age-matched pre- and postmenopausal women in order to define the temporal relationship between skeletal turnover and bone loss. In postmenopausal women, mean values of phosphatase activity, serum bone gamma-carboxyglutamic acid protein and urinary hydroxyproline were significantly higher, and mean values of mineral content were significantly lower than in premenopausal women. A marked loss of bone mineral content together with a persistent increase in skeletal turnover is already evident shortly after the menopause.

1-Carboxyglutamic Acid↗

Lack of inhibition of anterior pituitary hormone release during chronic treatment with calcium antagonists.

Calcium antagonists are widely used for the treatment of cardiovascular disorders, especially ischaemic heart disease. It has been demonstrated that these drugs, either in vitro or acutely administered in humans, inhibit the basal and stimulated secretion of pituitary hormones by blocking calcium influx through slow calcium channels. To see if a similar effect could be detected after their chronic administration, we studied the basal, TRH- and LHRH-stimulated TSH, PRL, LH and FSH release in 18 male subjects with chronic stable angina before and on the 30th day of oral treatment with verapamil (n = 8;80 mg three times a day) or with nifedipine (n = 10; 10 mg three times a day). Neither drug had any effect on basal TSH, PRL, LH and FSH values or on their response to the specific hypothalamic-releasing hormones. These results suggest that the chronic administration of calcium antagonists, at the usual therapeutic doses, does not effect the process of stimulus-secretion coupling of anterior pituitary hormones, ruling out any impairment of the related target glands which have been expected on the basis of previous studies.

Aged↗

A western blot characterization of Mycobacterium bovis antigens recognized by cattle sera.

The immune response to Mycobacterium bovis in cattle was assessed by Western blot. The antibody recognition pattern to M. bovis whole cell extracts and culture supernatant antigens was studied by using sera from M. bovis-infected (n = 62) and healthy (n = 38) cattle. Although the recognition patterns were highly variable, some proteins were regularly detected, mainly those with molecular masses of 17, 23, 28, 42, 66, 71 and 80 kDa in cellular extracts, and with molecular masses of 23 and 33 kDa in supernatants. Whole cell extract antigens were more frequently recognized than culture supernatant antigens. Healthy controls produced only a weak antibody response. The antibody response was variable, depending on tuberculosis stage. In early stages very few antibodies were detected. A response against the 66-kDa stress protein was mounted in intermediate tuberculosis and remained stable in more advanced disease. In late diseases, the preferentially recognized antigens were a 28-kDa cellular protein and supernatant antigens. The 28-kDa protein was studied in some detail. As determined by using monoclonal antibodies, the 28-kDa protein is different from superoxide dismutase. This protein aggregated in stored cell extracts and was not totally transferred to nitrocellulose. The principal conclusions of this work are: (i) whole cell extract proteins are more frequently recognized than the secreted proteins and (ii) a 28-kDa protein is a major antigen in late disease.

Animals↗

[The genotype of the principal Mycobacterium bovis in Argentina is also that of the British Isles: did bovine tuberculosis come from Great Britain?].

Bovine tuberculosis is a highly prevalent animal disease in Argentina. In this work evidence was obtained showing that a major Mycobacterium bovis group in Argentina had been introduced with the bovine bulls imported from the United Kingdom at the end of the XIX century. This evidence came from two sources: historical, obtained by bibliographical references, and from laboratory results, using a molecular typing method called spoligotyping. These strains are also present in other countries that introduced cattle from the same origin.

Animal Husbandry↗