Differentiation of steroidogenic cells in the developing adrenal gland of Testudo hermanni Gmelin, 1789 (chelonian reptiles).

The aim of this study was to investigate the development and differentiation of steroidogenic cells in the embryonic adrenal gland of Testudo hermanni using histological, histochemical, immunohistochemical and ultrastructural methods. The 26 developmental stages were divided into three periods: early (stages 1-18, up to 20 days of incubation), intermediate (stages 19-22, incubation days 21-35) and advanced (stages 23-26, from incubation day 36 to hatching). A small presumptive bud of steroidogenic cells was visible at the end of the early period, protruding into the coelom from the lateral wall of intermediate mesoderm. Ultrastructural characteristics suggested that young and scarcely differentiated cells could already be able to perform steroidogenic activity: lipid droplets, large amount of SER and RER, small rounded mitochondria with variously shaped cristae and dense matrix. The cell membrane showed microvilli and coated pits. During the intermediate period, the interrenal bud deepened into the haemopoietic tissue, close to the mesonephros and the newly formed metanephros. The ultrastructural, immunohistochemical and immunocytochemical characteristics pointed to enhanced steroidogenic activity. The contact with both kidney types (mesonephros and metanephros) continued in the advanced period, and chromaffin cells were also extensively mixed with steroidogenic cells. This is a peculiar feature of chelonian adrenal gland, in comparison with that of other reptiles. The variable cytological characteristics of embryonic steroidogenic cells in the advanced period suggest a four-phase cycle of steroidogenic activity.

Morphology and ultrastructure of the pronephros of Testudo hermanni Gmelin, 1789 (chelonian reptiles).

The aim of this study was to investigate the morphology and ultrastructure of the pronephros of Testudo hermanni as observed in the earlier part of its development. This paired structure appears during renal ontogenesis and originates from the first somites localised in the cephalic part of the embryo. The first pronephric evidence is noted at stage 12. The kidney is composed of large glomeruli that are devoid of a capsule and protrude into the coelomic cavity. A ciliated nephrostome provides access to short renal tubules, lined with a well-developed brush border. Two nephric ducts on the lateral sides of the embryo are connected to the tubules. The cytological characteristics of the pronephric structure suggest that it might be functional, at least in the first part of development. The pronephros of Testudo hermanni regresses after a short time around stage 18, while the mesonephros is already well differentiated. Its plesiomorphic characteristics, similar to those observed in amphibians, might be related to the phyletic position of chelonians within the reptiles.

Retinol-induced apoptosis in larval pancreas of Bufo bufo.

Tadpoles of Bufo bufo at the end of premetamorphosis were exposed to the action of retinol diluted in the rearing water at two concentrations: 20 and 40 microM, for 48 h. Assuming that retinol causes growth suppression by cell death induction, the TUNEL reaction for the detection of apoptotic cells was performed on paraffin sections of pancreas. The results showed that retinol induced a significant dose-dependent increase of number of apoptotic cells with respect to controls, in which apoptosis was scarce. Electron microscopic observations of treated specimens showed that the effects of retinol mostly occurred on exocrine cells: condensed crescent-shaped nuclear chromatin, dark cytoplasm with long projections; conversely, mitochondria and endoplasmic reticulum appeared unaffected.

Programmed cell death in the pancreas of Bufo bufo during metamorphosis.

Programmed cell death or apoptosis occurred in anuran amphibian larval pancreas as a remodelling agent, and was responsible for the reduction of the gland volume during metamorphosis. Apoptotic cells were recognisable by their morphological characteristics and could be immunocytochemically detected by means of the TUNEL reaction, which evidenced nuclear DNA fragmentation. During the last stages of prometamorphosis, that is in the period of hindlimb differentiation, only a few TUNEL positive cells occurred, whereas they increased at the beginning of metamorphic climax, that is at forelimb emergence and during tail regression. Under the electron microscope, the typical morphological characteristics of apoptosis were observed: decrease in size, and the presence of wide intercellular spaces and nuclei with dense chromatin masses arranged in crescents. The fragmentation of these cells produced the so-called 'apoptotic bodies': portions of cytoplasm lined by a membrane, containing nuclear fragments and cytoplasmic organites. Dead cell elimination is hypothesised to occur by phagocytic ingestion.

Pancreatic endocrine cells in Bufo bufo: immunocytochemistry and ultrastructure.

The endocrine pancreas of the toad consists of rounded islets of various sizes embedded in the exocrine tissue. Isolated cells are also present. At least 4 types of endocrine cell are distinguishable by shape, size and electrondensity of the secretory granules as well as by their immunoreactivity with different antisera: insulin, somatostatin, pancreatic polypeptide, and glucagon cells. Insulin cells can be divided into 2 types according to their cytoplasmic electrondensity. Colocalisation of different hormones in the same cell is rarely observed. The close contact between endocrine and exocrine cells and the scarcity of nerve supply is indicative of a paracrine control of hormone secretion.

The chromaffin cells of urodele amphibians.

Different conditions in the arrangement of the adrenal gland are observed in urodeles. The gland consists of islets scattered on the ventral surface of the kidneys, the amount, size and position of the islets varying consistently within different families and even within genera. The infraordinal variation also extends to the fine structure of the gland, as observed in 14 species belonging to 6 different families. The ultrastructural characteristics of chromaffin cells and their relationships with interrenal cells appear to be related to the phyletic position. In primitive urodeles (Sirenidae, Proteidae) the chromaffin cells are isolated or in small groups, mostly separated from interrenal cells and often in contact with renal cells. In neourodeles (Amphiumidae, Ambystomidae, Salamandridae, Plethodontidae) the chromaffin cells appear generally grouped and intermingled with steroidogenic cells. Some cytological characteristics of chromaffin cells, such as nerve supply and the shape and electron density of chromaffin granules exhibit a variability related to phyletic position.

The chromaffin cells of Siren lacertina (Amphibia, Urodela): cytological characteristics and evidence of exocytosis.

In the adrenal gland of Siren lacertina three types of chromaffin cells are described, on the basis of size, shape and electron density of the cytoplasmic granules: adrenaline-secreting cells, noradrenaline-secreting cells and small granulated chromaffin-cells. In A-cells exocytotic profiles are described, in which the granule membrane fuses with the plasma membrane and the granule core is discharged into the intercellular space.

Complement-fixing gastric parietal cell autoantibodies. A good marker for the identification of type A chronic atrophic gastritis.

Using an indirect immunofluorescence (IIF) technique, gastric parietal cell autoantibodies of IgG class (GPCA-IgG) were found in 2% of a normal population, in 5-26% of organ-specific autoimmune subjects and in 100% of patients with pernicious anaemia. With the exception of subjects with alopecia, there was a significantly increased prevalence of GPCA-IgG in autoimmune patients with respect to normal controls. GPCA of IgA class were detected in 22% of GPCA-IgG positive subjects, whereas GPCA of IgM class were uncommon. One-hundred and fifteen subjects underwent gastroscopy and body mucosal biopsy. Histopathological findings of chronic atrophic gastritis (CAG) were present in 71% of GPCA-IgG positive autoimmune patients without pernicious anaemia, in 100% of GPCA-IgG positive patients with pernicious anaemia, and in 20% of GPCA negative autoimmune patients. Complement-fixation test was performed in 46 GPCA-IgG positive subjects without pernicious anaemia using the IIF method. Twenty-nine patients (63%) were found to fix complement fractions till C9 (CF-GPCA) together with properdin factor, and in 25 of them (86%) the histological examination of body gastric mucosa disclosed a CAG (P = 0.0003 versus GPCA-IgG positive/CF negative controls). No significant difference was observed for the prevalence of CAG in GPCA-IgG positive/CF negative subjects with respect to GPCA-IgG negative control group. We conclude that the presence of CF-GPCA represents a useful immunological marker in the identification of CAG, while no predictive value seems to be associated with non-complement fixing GPCA-IgG.

Endoscopic treatment of stenosis following stapler anastomosis.

The papillotomy knife, introduced by an endoscope, was employed to treat stenosis following stapler anastomosis, and to cut the stenotic ring in three points along its circumference.

Morphogenesis of the adrenal gland of Triturus cristatus carnifex during larval development and metamorphosis.

During the morphogenesis of the adrenal gland of Triturus cristatus, a cranio-caudal differentiation is observed together with a migration of the two cell types composing the adrenal gland: the steroidogenic cells and the chromaffin cells. During the cranio-caudal differentiation the two cell type gradually occupy an increasingly posterior position on the mesonephros until they are distributed, in the adult, along the whole kidney. The migration brings the cells from dorsal or dorso-lateral position, with respect to the venous vessels, to the ventral surface of the kidney, an arrangement typical of the adult.

Incidence and significance of organ-specific autoimmune disorders (clinical, latent or only autoantibodies) in patients with vitiligo.

The frequency of autoimmune disorders was determined in 373 vitiligo patients and in controls matched for sex, age and race. Vitiligo patients had an increased frequency of clinical autoimmune diseases of thyroid (7.5%), stomach (0.8%), parathyroid (1%), adrenal gland (1.3%). Vitiligo patients, without clinical signs of overt autoimmune diseases, also had a statistically significant increase in the frequency of gastric parietal cell (p less than 0.001), thyroid microsomal (p less than 0.05) and adrenal autoantibodies (p less than 0.05). This increased incidence of autoimmune manifestations was correlated with the duration of vitiligo. Furthermore in 94% of the patients with parietal cell autoantibodies a gastric biopsy showed atrophic gastritis. In addition, in 48% of the patients with thyroid microsomal autoantibodies and in 2 out of 6 patients with adrenal autoantibodies without overt diseases at the beginning of the study, the functional investigation of the target organs during the follow-up allowed the detection of the presence or that of the subsequent development of clinical or subclinical dysfunction.

The adrenal gland of Euproctus (Urodela, Salamandridae): comparison of three species and phylogenetic inferences.

Adrenal glands of three species of Euproctus (E. asper, E. montanus and E. platycephalus) were compared. Differences were observed as regards: (1) the distribution of the adrenal tissue, which is more sparse in E. asper than in the other two species; (2) the amount and size of the adrenal islets: in E. asper, they are numerous and small, in E. platycephalus, they are decreased in number and larger, in E. montanus they are few and very large; (3) the distance of the islets from the medial border of the kidney is variable in E. asper; in E. montanus they are mostly in contact with the medial edge, whereas in E. platycephalus they are distant from it. The adrenals of E. montanus and E. platycephalus are more similar to each other than to that of E. asper; the gland in this species may be considered a more primitive type. Such structural relationships are in agreement with phylogenetic inferences concerning the three species.

Adrenaline-, noradrenaline- and small granule- containing cells in the adrenal gland of Discoglossus pictus (Amphibia, Anura).

In the adrenal gland of Discoglossus pictus, various types of chromaffin cells are described: noradrenaline cells, adrenaline cells and small granule-containing cells (on the basis of electron density and shape of the granules). The chromaffin cells occur in small groups, and have cytoplasmic processes which may surround them in the form of parallel layers. Their nerve supply is sparse. The possible function of SGC-cells, in relation to those described in other vertebrates, is discussed.