Immunohistochemical studies on human myocardial mast cells.

Immunoreactivity of resting human heart mast cells [MCs] to a wide variety of antisera was studied in the right atrial auricles and papillary muscles of patients subjected to open heart surgery. All MCs reacted positively to antisera against leukocyte common antigen, vimentin and histamine. Some MCs positively reacted with antisera against lysozyme, alpha 1-antitrypsin, alpha 1-antichymotrypsin, and S-100 protein. Immunostaining pattern was similar in papillary muscle MCs and atrial MCs. There was no reaction with antisera against epithelial, tumor, neuronal, and endocrine cell antigens used in this study. Our studies displayed the existence of differences in immunoreactivity between human neoplastic and reactive MCs and heart resting mast cells. This may reflect the heterogeneity of human MCs from different anatomic sites and/or different pathological processes.

Immunocytochemical studies on parafollicular cells of various mammals.

Using specific antisera, calcitonin, calcitonin gene-related peptide (CGRP), somatostatin as well as neuron-specific enolase, chromogranin, secretory peptide I and calbindin (vitamin D-dependent calcium-binding protein) were looked for in parafollicular cells of rats, Syrian hamsters, Mongolian gerbils, mice, guinea pigs, rabbits and pigs. Calcitonin and CGRP were most invariably present in various species. Somatostatin was absent in mice and Mongolian gerbils and present in variable amounts in the remaining species. Neuron-specific enolase could not be detected in rabbits, while in the pigs and the Mongolian gerbils it could be demonstrated only in some parafollicular cells. Calbindin was present exclusively in parafollicular cells of guinea pigs. Chromogranin and secretory protein-I were present only in some animal species.

Immunocytochemical studies on thyroid parafollicular cells in postnatal development of the rat.

Studies were performed on Wistar strain rats aged 1-720 days. Immunocytochemical reactions were used to detect calcitonin, somatostatin, calcitonin gene-related peptide (CGRP), cholecystokinin, serotonin, neuron-specific enolase (NSE), secretory protein-I, chromogranin and Ca-binding protein. In the parafollicular cells of the rat, the presence of calcitonin, somatostatin, CGRP, NSE and secretory protein-I could be demonstrated. The number of parafollicular cells increased with the age of animals, and the increase was particularly pronounced in the early postnatal period and after the first year of age. The number of somatostatin-immunoreactive cells decreased after birth and increased again after the first year of age. The number of calcitonin-immunoreactive cells increased in the early postnatal period independently of the increase in parafollicular cell number, forming frequently tumor-like outgrowths in 2-year-old animals. A small proportion of these outgrowths contained no calcitonin even if they did contain somatostatin, CGRP and NSE immunoreactivity. Evident changes in immunoreactivity in the first days after birth may reflect the sudden change in environment and may be associated with growth and differentiation. In any period of life, CGRP- and NSE-immunoreactive cells have constituted the most numerous groups and, therefore, the respective antigens seem to represent the most suitable markers of parafollicular cells in the rat.

Studies on localization of calcitonin gene-related peptide (CGRP) in the thyroid-parathyroid complex.

Calcitonin gene-related peptide (CGRP) was localized by an immunocytochemical technique in the thyroid-parathyroid complexes of rat, guinea pig, rabbit, and in normal human thyroids and parathyroids. Human medullary carcinomas and parathyroid adenomas were also studied. In man and all animal species examined CGRP was present in the parafollicular cell, however, in guinea pigs only in small amounts. Except in rabbits, presence of CGRP was demonstrated in nerves of the thyroid and parathyroid capsule as well as in the nerve fibers of the capsular blood vessels. In the thyroid of guinea pigs CGRP was also noted in nerve fibers and in blood vessel walls between follicles. CGRP was also present in the parathyroid glands of rat and man, in nerve fibers localized between parathyroid cells. In rabbit the parafollicular cells between parathyroid cells also expressed CGRP immunoreactivity. No CGRP was noted in the parathyroids of the guinea pig. The proximity of parathyroid cells and CGRP containing tissue structures suggests a role for CGRP in the modulation of parathyroid hormone secretion. The importance of these regulatory mechanisms appear to be different in individual species.

Immunocytochemical study of the distribution of S-100 protein in the parathyroid gland of rats and guinea pigs.

The distribution of S-100 protein in the parathyroid cells of normal and hypercalcaemic rats and guinea pigs was investigated. Previous studies had shown that the applied antibodies detect only the beta subunit of S-100 protein. S-100 protein was found in all parathyroid cells of rats aged between 1 and 720 days. In adult guinea pigs, S-100 protein was detectable in only a small proportion of parathyroid cells. The level of S-100 protein in individual cells exhibited considerable variation, particularly in guinea pig. Hypercalcaemia did not affect the distribution of S-100 protein in the parathyroid cells of either rats or guinea pigs. In both species, the presence of small groups of parathyroid cells in the central fragments of thyroid lobes was often noted.