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M M Vig

Publications and source records attributed to M M Vig.

10 recordsLinked to original sources
PubMed2000

Postnatal differentiation of efferent ductule epithelium in goats: a light microscopic and ultrastructural study.

Caprine efferent ductule epithelium contains ciliated and nonciliated cells. The latter cells are divided into three types: type II cells contain PAS-positive granules, type III cells contain PAS-negative vacuoles, and type I cells lack both granules and vacuoles (Goyal and Williams, Anat. Rec. 220:58-67). The objectives of this study are i) to determine when the epithelium differentiates into ciliated and nonciliated cells, ii) to determine when nonciliated cells acquire characteristics typical for type II and type III cells, and iii) to relate developmental changes in the epithelium with those in the testis. Testes and efferent ductules were examined at the light and electron microscopic levels in goats from 1-25 weeks of age. Efferent ductule epithelium contained ciliated and nonciliated cells as early as week 1. While ciliated cells were differentiated at week 1, differentiation of nonciliated cells did not occur until week > or =15. Differential features in ciliated cells included the presence of cilia at the apical border and an aggregation of mitochondria in the apical cytoplasm. Those in nonciliated cells included the presence of i) an endocytotic apparatus at week > or =15, ii) PAS-positive granules at week > or =15, and iii) PAS-negative vacuoles at week > or =25. The seminiferous tubules developed lumens at 12-15 weeks. Hence, while differentiation of ciliated cells occurred much before lumen formation in the seminiferous tubules, that of nonciliated cells coincided with, or occurred soon after, lumen formation, suggesting a role for testicular fluid contents in their differentiation. The goat efferent ductules can be characterized morphologically mature by 25 weeks.

Age Factors↗
PubMed1999

Postnatal differentiation of the ductus deferens, tail of the epididymis, and distal body of the epididymis in goats occurs independently of rete testis fluid.

Observations from extratesticular rete-ligated, mature goats indicated that epithelial morphology in the tail of the epididymis can be maintained without any input from testicular fluid (Goyal et al., Acta Anat., 1994;150: 127-135). Hence, the objective of this study was to determine whether the tail of the epididymis and/or other regions of the male excurrent ducts can differentiate prior to the appearance of lumen in the seminiferous tubules, which is an indicator for the onset of seminiferous tubular fluid secretion. Based on age and scrotal circumference (SC), 20 male goats were divided into four groups of five animals each: 1-4 weeks (SC, 6.5-7.5 cm), 7-10 weeks (SC, 8.5-11.0 cm), 12-15 weeks (SC, 11.0-14.0 cm), and 15-25 weeks (SC, 16.0-19.0 cm). Tissues were collected from the testis, six regions of the epididymis (proximal, middle and distal head; proximal and distal body; and tail), and the ductus deferens, and were processed for light and electron microscopic examination. Changes in epithelial height and cytological features associated with absorption (microvilli, pinocytotic and coated vesicles) and protein secretion (RER, Golgi body) were used as markers for differentiation. Differentiation of all of these features was comparable to that observed in the 15-25-week-old animals in the ductus deferens by > or = 1 week, in the tail of the epididymis by > or = 7 weeks, in the distal body of the epididymis by > or = 12 weeks, and in the proximal body of the epididymis and all three regions of the head of the epididymis by > or = 15 weeks. Seminiferous tubules developed lumens between 12 and 15 weeks. In conclusion, epithelial differentiation in the ductus deferens, tail of the epididymis, and distal body of the epididymis follows a time-dependent, spatial, ascending order and is achieved before lumen formation in the seminiferous tubules. Conversely, epithelial differentiation in all three regions of the head and the proximal body of the epididymis occurs simultaneously and after lumen formation in the seminiferous tubules.

Age Factors↗
PubMed1998

Regulation of androgen and estrogen receptors in male excurrent ducts of the goat: an immunohistochemical study.

BACKGROUND: Since androgens and/or estrogens must bind with specific receptors in order to elicit a response at the target organ(s), it is important to understand factors that regulate expression of androgen receptors (AR) and estrogen receptors (ER). Hence, the objective of the study is to determine the relative significance between circulating androgen (CA) and luminal androgen (LA) in maintaining normal expression of AR and ER in male excurrent ducts. METHODS: Mature Nubian goats were subjected for 15 days each to the following treatments: (1) bilateral orchidectomy, (2) bilateral orchidectomy and testosterone treatment, (3) unilateral ligation of the extratesticular rete, and (4) unilateral orchidectomy. Tissues from different segments of the excurrent ducts were fixed in 4% paraformaldehyde and embedded in Paraplast-plus. Antigenic sites for AR and ER were immunolocalized using PG-21 rabbit antirat/human antibody and H-222 rat antihuman monoclonal antibody, respectively. The avidin-biotin horseradish peroxidase procedure was used to identify positive immunoreactivity. Negative controls included incubation of sections with irrelevant IgG in place of primary antibody. RESULTS: In intact animals, whereas AR were found in epithelial, connective tissue, and peritubular smooth muscle cells of the efferent ductules, regions I-V of the epididymis, and ductus deferens, ER were confined to nonciliated cells of the efferent ductules. Bilateral orchidectomy caused a severe loss of both AR and ER staining. Testosterone replacement to orchidectomized animals restored staining of both AR and ER to the intact level. Neither unilateral ligation of the extratesticular rete nor unilateral orchidectomy had any effect on AR or ER immunostaining. CONCLUSION: Circulating androgen alone, without any input from luminal androgen or other rete fluid contents, can regulate expression of both androgen receptor and estrogen receptor.

Animals↗
PubMed1997

Immunolocalization of androgen receptor and estrogen receptor in the developing testis and excurrent ducts of goats.

BACKGROUND: Because of the significance of androgens and estrogens in prenatal and postanatal differentiation of the testis and excurrent ducts, it is important to understand the developmental pattern of androgen receptor (AR) and estrogen receptor (ER) in these organs. METHODS: Tissues from 1-23-week-old goats were fixed in 4% paraformaldehyde and embedded in Paraplast-plus. Antigenic sites for AR and ER were immunolocalized using the PG-21 rabbit anti-rat/human antibody and the H-222 rat anti-human monoclonal antibody, respectively. The avidin-biotin horseradish peroxidase procedure was used to identify positive immunoreactivity. Controls included incubation of sections with irrelevant IgG in place of primary antibody. RESULTS: Within the testis, immunostaining for AR in the nuclei of Sertoli cells increased gradually from mild at week 1 to strong at week > or = 19. In contrast, nuclei of peritubular myoid cells and Leydig cells exhibited moderate to strong reaction for AR in all animals. Germ cells were negative. Within the rete testis, efferent ductules, regions I-V of the epididymis, and ductus deferens, nuclei of all epithelial cells, peritubular myoid cells, and intertubular connective tissue cells expressed moderate to strong staining for AR at all ages. ER were confined to nonciliated cells of the efferent ductules, which displayed moderate staining in all animals, beginning from week 1. CONCLUSIONS: Nuclear AR staining, found in all testicular cells (except germ cells) and excurrent duct cells examined, was observed to change in an age-related manner only in Sertoli cells, where staining intensity increased between week 1 and week 19. Staining for ER, confined to nonciliated epithelial cells of the efferent ductules, was not affected by postnatal age.

Animals↗
PubMed1990

Nicotine poisoning in a dog.

Nicotine poisoning is a rarely reported toxicosis. The clinical signs and symptoms are complex and are mostly of central nervous system derangement. In addition, animals may have hypersalivation, vomiting, diarrhea, tachycardia, tachypnea, hypertension and hyperthermia. Some animals are presented in total collapse with slow and shallow respirations, hypotension, dilated pupils, and a weak, rapid and irregular pulse. Treatment is directed toward removing the unabsorbed poison and diluting, and counteracting or controlling the animal's signs. This report emphasises the comparative ease with which a dog would readily ingest chewing tobacco, which is sweet in taste, and come down with nicotine poisoning, as compared to cigarette tobacco which is nonpalatable and therefore less of a threat. The report further discusses clinical nicotine toxicosis, its incidence, clinical manifestations, diagnosis, prognosis and treatment.

Animals↗
PubMed1988

Effects of age and season on the type and occurrence of sperm abnormalities in Nubian bucks.

Effects of age and season on type and occurrence of sperm abnormalities were examined in semen samples collected from 3 groups of Nubian bucks at ages of 4 to 9 months, 10 to 21 months, and 39 to 50 months. The average total percentage of sperm abnormalities at the onset of puberty (141 +/- 4 days) was 64.6 +/- 14.8% (head, 19.5 +/- 13.6%; middle piece, 17.2 +/- 9.3%; and proximal protoplasmic droplets, 14.6 +/- 10.5%), but this improved rapidly and was reduced to 12.5 +/- 7.5% by 8 months of age (head, 1.9 +/- 4.5%; middle piece, 4.6 +/- 2.8%). Further increase in age, at least up to 4 years, did not reveal a significant effect (P less than 0.05) on the type or percentage of total abnormalities. Similar to age, a comparison of data among seasons did not reveal a significant effect on the type or occurrence of sperm abnormalities in 10- to 21-month-old or 39- to 50-month-old bucks. Seemingly, Nubian bucks started producing good quality semen at 8 months of age, and season did not influence sperm abnormalities.

Aging↗
PubMed1987

Serum levels and pharmacokinetics of ticarcillin and clavulanic acid in dog following parenteral administration of Timentin.

The serum concentration-time data for ticarcillin (TICAR) and clavulanic acid (CLA) following intravenous and intramuscular administration of Timentin (TICAR, 50 mg/kg with CLA, 1.7 mg/kg) indicated that absorption of CLA following intramuscular injection and its overall elimination from the body was faster than that of TICAR. This is supported by comparison of certain pharmacokinetic parameters for TICAR and CLA. These include the shorter value of Tmax for CLA (11.45 +/- 1.60 min) than that for TICAR (29.93 +/- 1.94 min) and significant variation in the elimination rate constants (0.183 +/- 0.0018 min -1 for CLA vs. 0.0097 +/- 0.0006 min -1 for TICAR) for the intravenous group of animals. The biological half-life of CLA (approximately 39 min) was significantly shorter (P less than 0.01) than that of TICAR (approximately 73 min). In spite of initial faster absorption, the intramuscular bioavailability of CLA (65.02%) was less than that of TICAR (91.37%). Though the pharmacokinetic behaviour of TICAR and CLA is not similar, yet based on the therapeutically optimal concentrations of CLA and TICAR reached in serum, Timentin at the dose used in the present study should be effective in treating most TICAR-resistant Enterobacteriaceae infections in dogs. Timentin is not likely to be effective in the treatment of infections caused by TICAR-resistant pseudomonads, at the dose used in the present study.

Animals↗
PubMed1984

Histochemical activity of alkaline phosphatase and acid phosphatase in the epididymis of mature intact and androgen-deprived bulls.

The histochemical localization of alkaline phosphatase (ALP) and acid phosphatase (ACP) was determined in regions I to VI of the epididymis in mature intact, orchidectomized, and orchidectomized testosterone-treated bulls. The intensity of ALP activity was essentially the same in all regions; however, its localization varied depending upon the region. Although the stereocilia and luminal border of epithelial cells were strongly-positive in regions I to III, these were negative in regions IV to VI. The basement membrane and circumtubular smooth muscle cells were strongly ALP reactive in all regions. Epithelial ALP activity was abolished completely by orchidectomy; however, it was restored to normal concentration by testosterone treatment implying its dependence on circulating testosterone. The ACP activity was present in the epithelial cells of all regions with the strongest activity in the supranuclear region. Similar to ALP, ACP activity was markedly reduced in the epithelial cells by orchidectomy. However, in contrast to ALP activity, lost ACP activity was only minimally increased by testosterone treatment in all regions, except in region VI where it was restored to a normal concentration. These observations imply that although the epithelial ACP activity of region VI was mainly under the influence of circulatory testosterone, there may be other factors such as luminal androgens, testicular fluid, and sperm that may be important in regulating the ACP activity of regions I to V of the epididymis. The importance of ALP and ACP in the epididymal epithelium was discussed.

Acid Phosphatase↗
PubMed1979

Exteriorization of the bile duct in germfree rats.

A modified T cannula and a cannula housing receptacle was employed to cannulate the bile duct of germfree rats. Bile was collected without anesthesia or sedation. During collection, the rat was restrained in a plastic holder where it was free to eat.

Animals↗