Irene von Lawzewitsch

Reproduction in the Male Llama (Lama glama), a South American Camelid

The cycle of the seminiferous epithelium of the llama was divided into eight stages, using as criteria the shape and distribution of the germ cell nuclei, the location of the spermatids, the presence of meiotic figures and the release of spermatozoa from the tubular wall. Cell populations making up each stage are described. The relative frequencies of stages 1 through 8 were: 9.86, 12.46, 17.65, 14.12, 5.81, 8.09, 13.04 and 18.89%, respectively. In the seminiferous epithelium, spermatogonia of the A and B type are present and twelve spermiogenic steps can be recognized. Interstitial (Leydig) cells are packaged together forming large masses and elongated cords and share the intertubular space with one or two central great lymphatic vessels and few capillaries. Season male Leydig cells contain lipid droplets in their cytoplasm and show a marked immunoreactive testosterone reaction.

Effect of estrogens on blood sugar, serum insulin and serum free fatty acids, and pancreas cytology in female dogs

SummaryWe analyzed the changes in blood sugar (BS), serum immunoreactive insulin (IRI), circulating free fatty acids (FFA) and pancreatic cytology caused by estrogenization at low pharmacological dosage in female dogs. Vehicle-injected and untreated controls (anestrus) were studied as well. Neither mean basal BS nor basal serum IRI was modified by the treatments, while the mean basal serum FFA value was raised. Glucose tolerance was not modified by the estrogens while glucosey-mean was significantly raised. Hyperglycemia was higher for a longer time in estrogenized animals compared to both controls, while the profiles of hyperinsulinemia coincided. In the estrogen-treated bitches, the pancreatic B-cells contained scarse brown-stained granules near their vascular pole, as shown by an immunochemical method. In the peripheral part of the pancreas, near the acini, some solitary, poorly β-granulated B-cells were present. During the IVGTT, serum FFA reached lower values for a longer time in the estrogenized bitches as compared to those found in both control groups. Insulin-induced hypoglycemia in the estrogenized animals coincided with the one evoked in the vehicle controls; in the semilog relationship of serum IRI and time,y-mean was lower than that observed in oil-injected controls, and insulin space was larger. The serum FFA levels of the estrogenized bitches, very high in the basal conditions, did not respond to insulin administration, and were above those found in untreated controls and also in vehicle-injected controls just at the beginning of the test. These results are discussed. We came to the conclusion that estrogenization causes some glucose intolerance in bitches while insulin sensitivity remains normal in the IVITT as studied measuring BS. The glucose intolerance is thought to be related to a reduction in glucose space and occurs despite the normality of the serum IRI response. The pancreas must have an intense secretory responsein vivo so as to maintain normal IRI activity despite degranulation of the islets of Langerhans and poor islet hypertrophy and neoformation. The serum FFA changes are thought to contribute towards the tendency to adiposity in these animals.

Microscopic anatomy of the ovary ofAlouatta caraya

The microscopic structure of theAlouatta caraya ovary is studied in different ages and reproductive stages. The most significant feature seems to be the presence in adult ovaries of abundant glandular interstitial tissue which occupies both the cortex and medulla. It seems to be derived from the theca interna of atretic follicles. Discrete luteinized masses are present in the medulla in all the ovaries observed. Invaginations of the surface epithelium are seen only in infant and juvenile ovaries. The development of cystic follicles seems to be a common pathway of atresia.

In vivo effect of beef hypothalamic extracts on the cells of rat adenohypophysis.

Administration of crude and semipurified beef hypothalamic extracts to normal male rats resulted in a considerable degranulation of acidophil, thyrotropic and gonadotropic cells of the adenohypophysis. This effect was evidenced from 10 to 20 min after intracarotid injection of these extracts. At 60 min, the three groups of cells showed moderate hypertrophy, and the chromophobe cells also showed some degree of enlargement. By 90 min, acidophils were apparently normal, whereas thyrotrophs and gonadotrophs were partially degranulated and vacuolized. These effects coincided with a drop in pituitary FSH (follicle-stimulating hormone) and LH (luteinizing hormone), as evidenced by specific bioassays in animals injected with similar extracts. The control animals, whether sham-operated or injected with saline, vasopressin or brain cortical extracts, did not show any degranulation in the adenohypophyseal cells. This investigation demonstrated that the well-known effect of hypothalamic extracts on pituitary tropins can also be evidenced at a histological level.

Pancreatic islets in Platyrrhini monkeys:Callithrix jacchus, Saimiri boliviensis, Aotus azarae, andCebus apella. A cytological and immunocytochemical study

A histochemical and immunocytochemical study was performed to describe the cellular localization of four hormones in pancreatic tissue of the Callithricidae and Cebidae families belonging to Platyrrhini monkeys. Insulin, somatostatin, glucagon, and gastrin immunoreactive cells were detected in the pancreatic islets at light microscope level. Beta cells (insulin positve) were distributed in a peripheral mantle or in irregular clusters in a polar region of the islet. Also little groups (small islets) from three to six beta cells distributed in the pancreatic stroma were observed in all the species. A constant feature was the presence of neuroinsular complexes. The alpha cell population was composed of orangeophiles or phloxinophile cells and presented an heterogeneous composition as the result of their granular type (difference in immunocytochemical affinity). Alpha 1 cells (somatostatin) were scattered between the other cells or in the periphery of the islets, while alpha 2 cells (glucagon) were distributed in three different ways: (1) occupying polar positions; (2) disseminated in small groups; or (3) arranged in cord-like disposition. One or two G cells (gastrin) were found in few islets.

The Respiratory System of the Genus Callithrix, the South American Monkey*

It has been described the cytology of the following parts of the respiratory system of some South American primates:Callithrix jacchus andCallithrix argentata melanura.The nasal cavities are divided into three parts: a vestibule, covered with a stratified nonkeratinized squamous epithelium; the respiratory portion, consisting of a pseudostratified columnar ciliated epithelium with goblet cells and the olfactory portion which is also covered with a high respiratory epithelium without goblet cells.The trachea is lined with a mucous membrane, whose epithelium is pseudostratified columnar ciliated with scarce goblet cells in the proximal portion unlike to the distal one. In the dorsal portion of the trachea, at the level of the gap between the two ends of incomplete cartilaginous rings, the epithelial lining is of transitional type. The incomplete hyaline cartilaginous rings present centers of calcification.The right and left lungs consist of two and three lobes respectively characteristic for these species, but they are not divided into lobules by connective tissue as in other ones.The bronchi, bronchioles and the respiratory portion, respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli present the typical respiratory structure with exception of their cartilaginous configuration; the cartilage continues as far as the respiratory bronchioles and alveolar ducts. These last structures are formed by a thin squamous epithelium, in which we observed two types of alveolar lining cells.

Effects of short-term thyroxine treatment on pancreatic cytology and responses of blood sugar, serum insulin and serum free fatty acids to epinephrine infusion

The influence of short-term treatment with l-thyroxine on pancreatic histology and on the responses of glycemia, insulinemia and serum free fatty acids to a continuous l-epinephrine infusion in the absence or presence of alpha- and beta-adrenergic blockade was studied in male dogs. l-Epinephrine dosage: 0.06 microgram/kg body weight/min for 55 min. Two experimental groups were studied, one treated for 10 days with sodium l-thyroxine, one daily dose of 100 micrograms/kg body weight, the other of untreated controls. Three alternative treatments were applied to dogs of both groups: 1) no treatment; 2) alpha-adrenergic blockade with phentolamine (2.0 mg/kg body weight, 35 min before starting the l-epinephrine infusion); 3) beta-adrenergic blockade with propranolol (0.3 mg/kg body weight, 20 min before starting the l-epinephrine infusion). Body weight, rectal temperature, heart and respiratory rates were used as guidelines to assess experimental hyperthyroidism. Insulin immunocytolocalization was also studied in the Langerhans islets of T4-treated and control dogs. Body weight decreased and rectal temperature did not vary as a result of thyroxine administration which had no significant effect on respiratory and heart rate. The mean number of breaths from 0 to 120 min from the start of l-epinephrine infusion decreased in both T4-treated and control dogs submitted to propranolol blockage compared to non-blocked animals; phentolamine had no effect on the respiratory rate. Thyroxine treatment did not modify the number of heart beats, but phentolamine blockade had a different effect in T4-treated compared to control dogs whereas propranolol had similar effects in these two groups. Histological examination of the Langerhans islets of dogs submitted to short-term thyroxine treatment showed degranulation though no vacuolation. Most of the beta-granules contained in the B-cells of these islets were found near the cell membrane, thus forming a dark brown line after the immunochemical reaction. Since negative images of B-cell nuclei and vascular spaces were predominant in these specimens, the pancreas of T4-treated dogs presented a mesh structure. In dogs submitted to short-term thyroxine treatment, the hyperglycemic response to l-epinephrine was enhanced and prolonged as compared to untreated controls. In normal dogs, this response is mainly mediated by alpha-adrenergic receptors while beta-receptors hardly influence this response.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of Sulpiride on the Adenohypophysis of Castrated Male Rats

Previous studies have shown that N-[(1-ethyl-2-pyrrolidinyl)methyl])-2-methoxy-5-sulfamoylbenzamide (sulpiride), a psychotrophic drug of clinical use, is a potent antidopaminergic agent, and acts on pPrevious studies have shown that N-[(1-ethyl-2-pyrrolidinyl)methyl] )-2-methoxy-5-sulfamoylbenzamide (sulpiride), a psychotrophic drug of clinical use, is a potent antidopaminergic agent, and acts on prolactin and gonadotroph secretions. Cytological changes caused by the effects of this drug were studied in castrated male rats treated with daily doses of sulpiride 5 mg/100 g body weight. Animals were sacrificed 2 months after treatment and their hypophyses processed for cytological and immunohistochemical studies. Cytomorphometry was carried out at the ultrastructural level. An immunocytochemical study was performed with peroxidase-labelled antibody to determine PRL, FSH and LH hormones in gland sections. The administration of sulpiride produced a decrease in granules of prolactin cells. Only the Golgi region showed a positive prolactin reaction and the cytomorphometric study indicated an increase of the area occupied by the endoplasmic reticulum and Golgi complex. In gonadotrophs, treatment with sulpiride decreased the vacuolatin caused by castration. The area occupied by the endoplasmic reticulum was smaller, whereas that occupied by secretion granules and lysosomes became larger. It is suggested that sulpiride treatment increased markedly the mammotroph activity and decreased the gonadotroph one, restoring the vacuolation of the endoplasmic reticulum vacuolation to normal.