Morphological and histochemical study of the submandibular gland in Praomys (Mastomys) natalensis

The submandibular gland in female and male Praomys (Mastomys) natalensis (a South African multimammate rodent) was studied using light microscopy and techniques for the demonstration of carbohydrates. Hematoxylin and eosin stain revealed the presence of a single secreting component that gave a strongly positive PAS reaction. Limiting elements of the granular tubules gave a weakly positive PAS reaction. Acidic glycoproteins were evidenced only in granules of the acinar component.     

An electrophoretic polymorphism in the serum transferrins of Praomys (Mastomys) natalensis

Three serum transferrin phenotypes of Praomys (Mastomys) natalensis, an African rodent having a high incidence of many varieties of spontaneous neoplasms, were detected by electrophoresis and autoradiography. On electrophoresis, transferrin of Trf-K was found to be a protein that migrates slowly toward the cathode, whereas that of Trf-M migrates rapidly. Trf-KM is a heterozygous phenotype of the above two. Progeny testing demonstrated that these three serum transferrin phenotypes in Mastomys are probably controlled by two codominant allelic genes, Trf ^k and Trf ^m , at a single autosomal locus. The genotypes of these phenotypes may be Trf ^k /Trf ^k , Trf ^m /Trf ^m , and Trf ^k /Trf^m.     

The ultrastructure of the male and female prostate of Praomys (Mastomys) natalensis

Summary Male ventral and female prostates of Praomys (Mastomys) natalensis were examined with the electron microscope. The findings support and add to information obtained with the light microscope on tissues from normal, castrated and ovariectomised animals.Our results indicate that although the female prostate may be considered a homologue of the male ventral prostate anatomically and histologically, there are differences in sub-cellular morphology and hormone dependence.Cells of the intact ventral prostate of the male are characterised by prominent dilated Golgi vesicles and electron-dense mature secretory granules seen in the apical region of the cell. In the cells of the female prostate these features are absent. These morphological differences reflect the influence of hormones upon the cells, as shown by the reduction of the dilated Golgi vesicles in the castrated male and conversely, their occasional presence in the cells of the oestrous female.Comparison of castrated and ovariectomised animals shows that the male ventral prostate is much more dependent on androgens than the female is on ovarian hormones.There are several modes of secretion in the male ventral and the female prostate. These are by acellular and cellular blebbing, by a variety of secretory vesicles into the acinar lumina, and by a system of double walled vesicles not previously described.We are grateful to Dr. R.C.B. Pugh of the Department of Pathology, St. Peter's Hospitals for helpful discussion, to Mr. P. Chaloner and Miss P. Gunter for technical assistance and also the Department of Medical Art of the Institute of Urology     

Histochemical localization of prostaglandin-synthetase in the salivary glands of Praomys (Mastomys) natalensis

The cellular distribution of prostaglandin-synthetase was studied in the salivary glands of Praomys (Mastomys) natalensis. Only the epithelial cells of the ducts showed discrete prostaglandin-synthetase activity, whereas the acini and the stroma gave completely negative results in all three salivary glands of both sexes. The presence of exogenous substrates was not required for the reaction, since identical results are observed following incubation with and without arachidonic acid. The localization of prostaglandin synthetase in the ductal epithelia of Praomys salivary glands is related to a possible regulatory role of the prostaglandins on the reabsorptive activity of the ductal cells.     

Praomys (Mastomys) natalensis: a model for gastric carcinoid formation.

The gastric carcinoid tumors of Praomys (Mastomys) natalensis have been reviewed with respect to histogenesis, development, biochemistry, and morphological properties. Multicentric gastric carcinoids frequently develop in the oxyntic mucosa of aging Mastomys. The development of these tumors can be significantly enhanced by drug-induced hypergastrinemia, e.g., histamine2-receptor blockade. Spontaneous and drug-induced gastric carcinoids are endocrine in nature, as evidenced by their argyrophilic staining properties and chromogranin A content. They are also rich in histidine decarboxylase activity and produce large amounts of histamine, although other hormones, such as peptide YY and enteroglucagon, have also been demonstrated in these tumors. Ultrastructurally, gastric carcinoids are composed of tumor cells with typical secretory granules resembling those of enterochromaffin-like (ECL) cells. A close examination of the gastric carcinoids in Mastomys reveals striking similarities with gastric carcinoids developing in humans suffering from chronic atrophic gastritis type A or from the Zollinger-Ellison syndrome in combination with multiple endocrine neoplasia type 1 (MEN-1). Both these conditions are associated with hypergastrinemia and a higher risk for developing multi-centric gastric carcinoids of ECL-cell origin. The Mastomys tumor model therefore appears to be a significant experimental model in which induction and formation of gastric carcinoid tumors can be studied.     

Histochemical determination of carbohydrates in the prostate of male and female Praomys (Mastomys) natalensis

The ventral lobes of the prostate in the female and male Praomys (Mastomys) natalensis were studied using light microscopic techniques for the demonstration and localization of carbohydrates. A weakly PAS-positive material appeared in the secretory product and secretory granules in epithelial cells of both female and male ventral lobes. This reaction is unaffected by diastase and is completely blocked by acetylation. Alcian blue, toluidine blue and methylene blue stains demonstrate metachromatic changes only after sulphation. All reactions indicate the presence of neutral mucosubstances in the secretory product and secretory granules of epithelial cells of the ventral lobes in either sex.     

Distribution of sibling species of the Praomys (Mastomys) natalensis group in Rhodesia (Mammalia: Rodentia)

The taxon Praomys ( Mastomys ) natalensis, the multimammate mouse, comprises at least two biological species in Rhodesia. Species-specific haemoglobin phenotypes which were previously documented for sympatric populations near Salisbury are shown to apply throughout Rhodesia. Several areas of sympatry were revealed which encompassed various habitats. No hybrids for diploid number or haemoglobin phenotype were found.     

Cytochemical demonstration of enzymatic activities of the parotid, submandibular, and sublingual glands of Praomys (Mastomys) Natalensis

Histochemical techniques were applied to salivary glands removed from adult multimmate rodents (Praomys) of either sex to detect and localize the following enzymatic activities: acid and alkaline phosphatase, arylsulphatase, ali-esterases, beta-glucuronidase, N-acetyl-betaglucosaminidase, and L-leucyl-aminopeptidase. No reaction was observed for alkaline phosphatase and glucuronidase. The glands reacted differently to the other enzymatic activities. Alkaline phosphatase and glucosaminidase were present only in one glandular type whereas arysulphatase and esterases were present in all types although demonstrating a variable staining intensity in different glands. Sharp differences in some enzymatic activities of the submandibular and parotid glands were related to the sex of the animal.     

Morphological and histochemical studies on the prostate gland of developing and adult Paramphistomum cervi (Digenea: Paramphistomatidae)

Morphological and histochemical studies have been made on the development of the prostate gland of the digenetic trematode, Paramphistomum cervi during the course of its infection in sheep; histochemical characterization of prostate gland secretion in adult worms and its functional relationship with the transport of spermatozoa have also been studied. In 6-wk-old worms, the terminal portion of the male genital duct is formed of what appears to be a syncytial epithelium containing a relatively large number of nuclei compared to the rest of the male duct. Cellular organization of the prostate gland becomes conspicuous in 8-wk-old worms and the prostate gland is fully developed by 16 wk. Two types of prostate gland cells, characteristic of the adult, become distinct in 16-wk-old worms which contain spermatozoa in the lumen of their vas deferens and pars prostatica. Adult worms show two types of prostate gland cells: type I containing mainly glycoprotein and type II mainly phospholipid granules. Weak-to-strong activities of acid phosphatase, alkaline phosphatase, esterase, lipase, adenosine triphosphatase, tetrazolium reductase, NAD-diaphorase, isocitrate dehydrogenase, glyceraldehyde dehydrogenase, α-glycerophosphate dehydrogenase and glucose-6-phosphate dehydrogenase have been observed in the prostate gland. The release of prostate gland secretion and the passage of spermatozoa through the lumen of pars prostatica appear to be synchronized events.     

Morphological, micromorphological and histochemical studies on the parotid salivary glands of the one-humped camel (Camelus dromedarius).

The morphology, blood and nerve supply of the parotid salivary glands of the one-humped camel were studied in detail. The intraglandular portion of the duct system was also examined. The histological and histochemical studies showed that the parotid salivary glands of the camel are of the tubuloacinar type and are serumocoid in nature. The secretory acini and tubules show themselves in 3 different forms according to the different phases of their secretory cycle. The duct system of the gland contains goblet cells between its lining epithelium. The intercalated ducts show ampullation followed by narrowing that help in mixing the secretion. Intraepithelial glands are found in the terminal part of the parotid duct.