Serum biochemical values in two inbred strains of mastomys (Praomys coucha).

Serum samples collected from 119 (72 male and 47 female) mastomys (Praomys coucha) of 2 specific-pathogen-free inbred strains (RI4 and RI7) were analyzed for 12 serum biochemical parameters. Sex-related differences (p < 0.01) were noted in alkaline phosphatase and glucose; the both higher in females than in males. Age-related changes (p < 0.01) were observed in total protein, albumin, total cholesterol, and alkaline phosphatase, with higher values for the first three parameters in the older group (200-250 days of age) than in the younger group (90-140 days of age). Four out of 12 parameters showed strain-related differences (p < 0.01), consistent with the large amount of genetic heterogeneity reported in this species. These serum biochemical reference values should provide information for the use of mastomys in laboratory research.     

Effects of lactation on the border zone formation in the female mastomys (Praomys coucha) adrenal cortex.

Adrenocortical zonation and especially border zone formation were investigated in relation to reproduction in female mastomys of the wild-colored inbred strain (MWC). The adrenal weight and the whole thickness of the cortex remained relatively constant throughout pregnancy, delivery and lactation. During pregnancy the zona fasciculata increased, but the z. reticularis decreased in thickness. The border zone between the z. fasciculata and the z. reticularis thickened 2-fold during pregnancy and further 2-fold during lactation. This zone was composed of vacuolated cell layers and nodules in females with a normal reproductive career. In young virgins this zone was barely identified by the presence of a few highly vacuolated cells. These cells became prominent during pregnancy and lactation. During lactation two types of cell aggregations, distinguishable by their stainability, vacuolation, localization and cellularity, appeared in the thickened border zone. The nodules first appeared within the z. reticularis after lactation. Neither thickening of both border zone and z. fasciculata nor formation of nodules occurred when lactation was interrupted after delivery. Thus, the changes in the female MWC adrenal, above all the appearance of nodules, seemed to be more dependent upon lactation than pregnancy. The vacuolated cells and the nodules might originate from the thickened z. fasciculata and the thinned z. reticularis, respectively, by the specific metamorphosis of the cells adjacent to the border zone. Their fusion and induction of fibrous tissue migration may result in the wider border zone.     

Fertilization of oocytes and birth of normal pups following intracytoplasmic injection with spermatids in mastomys (Praomys coucha)

The mastomys is a small laboratory rodent that is native to Africa. Although it has been used for research concerning reproductive biology, in vitro fertilization (IVF) and intracytoplasmic sperm injection are very difficult in mastomys because of technical problems, such as inadequate sperm capacitation and large sperm heads. The present study was undertaken to examine whether mastomys spermatids could be used to fertilize oocytes in vitro using a microinsemination technique, because spermatids are more easily injected than mature spermatozoa into oocytes. Most mastomys oocytes (80%-90%) survived intracytoplasmic injection with either round or elongated spermatids. Round spermatids had little oocyte-activating capacity, similar to those of mice and rats, and exogenous stimuli were needed for normal fertilization. Treatment with an electric pulse in the presence of 50 microM Ca2+ followed by culture in 10 mM SrCl2 led to successful oocyte activation. After injection of round spermatids into preactivated oocytes, 93% of oocytes were normally fertilized (male and female pronuclei formed), and 100% of cultured oocytes developed to the 2-cell stage. However, none reached term after transfer into recipient females. Elongated spermatids, which correspond to steps 9-11 in rats, activated oocytes on injection without additional activation treatment. After embryo transfer, five offspring (6% per transfer) developed to term. These results indicate that microinsemination with spermatids is a feasible alternative in animal species that are refractory to IVF and sperm injection and that using later-stage spermatids may lead to increased production of viable embryos that can develop into normal offspring.     

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.     

Adrenocortical zonation of inbred wild-coloured mastomys, Praomys coucha: a new border zone in the cortex of females

Adrenal glands were examined in the inbred strain of wild-coloured mastomys (Praomys coucha), MWC. The most characteristic findings were emergence of a border zone between the zona fasciculata and z. reticularis of the cortex in females but not in males, and persistence of broad z. reticularis in males. The border zone was typically comprised of vacuolated cell layers, nodular layers and fibrous tissue. Vacuolated cells increased in number during pregnancy and partially disappeared during lactation. Growth of the nodules was greatly enhanced in both number and size during lactation. Thus, multiparae had very thick border zones composed predominantly of large nodules and, additionally, of vacuolated cells and fibrous tissue. The z. reticularis was compressed into a cord of closely packed cells by the expanded border zone in multiparous females but it continued to thicken with age in males. These changes produced completely different cortical zonation in the adrenal between sexes.     

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.     

Morphology and electrophoretic protein profiles of female salivary glands in four Oriental black fly species (Diptera: Simuliidae).

Saliva of female flies is responsible for localized hypersensitivity reactions and life-threatening systemic hemorrhagic syndromes in humans and animals. In this study, morphology and electrophoretic protein profiles of female salivary glands of Oriental black flies in the subgenus Simulium Latreille s. str., Simulium (Simulium) nigrogilvum, S. (S.) rufibasis, S. (S.) nodosum, and subgenus Gomphostilbia Enderlein, S. (Gomphostilbia) asakoae were analyzed. The paired female salivary glands of the four simuliid species were morphologically similar and situated on either side of the esophagus. Each gland is composed of two main parts, a secretory arm and a reservoir. In each species, the size of the gland correlated with salivary gland protein contents. SDS-PAGE analysis revealed differences of electrophoretic protein profiles and specifically major protein bands of the female salivary glands in each species, suggesting that protein profiles might be useful for construction of an additional tool to distinguish these black fly species. The information obtained from this study is an initial step for further research on salivary proteins that are involved in vertebrate hemostatic response.     

The submaxillary salivary glands of the African rodent Praomys (mastomys) natalensis as the richest available source of the nerve growth factor

It is the object of this report to compare the biological, biochemical activity and the immunocytochemical localization of nerve growth factor (NGF) in the submaxillary glands of Praomys (mastomys) natalensis and mouse. Biological and radioimmunoassays gave evidence of a higher NGF activity in the soluble extract of submaxillary glands of male and female mastomys than in the male mouse homologous glands. Histological and immunocytochemical studies showed that, in contrast to mouse submaxillary glands, these mastomys glands exhibit a very attenuated sexual dimorphism. Immunocytochemistry and radioimmunoassay revealed a similarity—but not identity—of mouse and mastomys NGFs.     

1-Naphthol basic dye (1-NBD). An alternative to diaminobenzidine (DAB) in immunoperoxidase techniques

The usefulness of 1-naphthol as substrate for horseradish peroxidase (HRP) in immunohistochemistry was studied using the peroxidase-antiperoxidase (PAP) and avidin-biotin-complex (ABC) methods in the demonstration of glial fibrillary acidic protein (GFAP), vimentin, carbonic anhydrase C (CA.C), and factor VIII-related antigen (FVIII/RAg) in central nervous tissue and cerebral tumors. In the presence of ammonium carbonate, 1-naphthol is oxidized by HRP and hydrogen peroxide, producing a fine gray-violet precipitate. The oxidation product of 1-naphthol proved capable of binding a great number of basic dyes. For each stain the final reaction product had a characteristic color that was different from the spontaneous color of the dye and from the color displayed by nuclei. The final color obtained with this procedure was alcohol resistant and could be mounted in solvent-based mounting media. The results obtained with the 1-naphthol basic dye (1-NBD) method were compared with those obtained using the diaminobenzidine (DAB) reaction in the demonstration of GFAP-positive astrocytes. The DAB reaction produced a more intense staining but also a coarser precipitate than the 1-NBD reaction. The 1-NBD procedure showed more morphological detail of fine structures and did not obscure nuclei and mitosis. The very low toxicity of 1-naphthol compared with DAB (a suspected carcinogen) is an important advantage of the 1-NBD method, as is its high specificity and sensitivity.     

An RsaI polymorphism in the transcribed region of the neurofibromatosis (NF1)-gene

We describe an RsaI polymorphism in the transcribed region (exon 5) of the neurofibromatosis type 1 (NF1)-gene