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R Rajamahendran

Publications and source records attributed to R Rajamahendran.

42 records · Page 3Linked to original sources
PubMed1985

Observations on in vitro development of bovine morulae in Ham's F-10 and Dulbecco's phosphate buffered saline supplemented with normal steer serum.

This study was conducted to compare in vitro development of bovine morulae in Ham's F-10 and Dulbecco's phosphate buffered saline (D-PBS) media supplemented with 10% (v/v) normal steer serum. Fifty-three excellent and good embryos were obtained by superovulating 15 non-lactating Holstein cows. Embryos were placed randomly in culture with Ham's F-10 or D-PBS media and development was recorded at 12-h intervals for the duration of culture. All embryos reached early blastocyst, blastocyst and expanded blastocyst stage. Nineteen of 27 embryos (70.1%) cultured in Ham's F-10 developed to hatched blastocyst stage in contrast to three out of 26 in D-PBS (11.5%). The mean developmental scores at 24, 48, 72, 96 and 120 h of culture were significantly (P<0.001) higher for embryos cultured in Ham's F-10. Also, the mean times to reach early blastocyst (25.84 +/- 6.65 vs 46.67 +/- 9.99 h), blastocyst (44.57 +/- 11.45 vs 61.89 +/- 16.62 h) and expanded blastocyst stage (65.00 +/- 13.20 vs 73.41 +/- 15.80 h) were significantly (P<0.001) shorter for embryos cultured in Ham's F-10. No difference was observed in the mean time to reach hatching (90.00 +/- 10.85 vs 84.00 +/- 16.97 h) and hatched blastocyst stage (97.26 +/- 18.71 vs 96.00 +/- 0.00 h). The results obtained support the concept that Ham's F-10 and normal steer serum provide for optimal bovine embryo development and suggest that 10% normal steer serum could be used as a protein supplement with D-PBS for short term storage and culture of bovine embryos.

Journal Article↗
PubMed1981

Libido and semen characteristics of Murrah, Surti, and local buffalo bulls in Sri Lanka.

The sperm properties and the libido were investigated in four Murrahs, three Surtis, and one local buffalo over a period of four months. As regards their libido, no specific features were found for the different breeds. The volume of the ejaculates and the concentration of the sperms were highest in the Murrah buffaloes, but they also exhibited the highest proportion of dead sperms in the first ejaculate. The local buffalo bull had a greater ejaculate than the Surti bulls but its sperm concentration was smaller and the proportion of dead and/or abnormal sperms was higher. Comparing the first and the second ejaculate, significant differences were found as regards the proportion of dead sperms and the motility in Murrah bulls, the sperm concentration and the proportion of dead sperms in Surti bulls, and proportion of abnormal sperms in the local buffalo bull.

Animals↗
PubMed1976

Luteolytic activity of a synthetic prostaglandin and PGF2alpha in heifers.

Two experiments involving 44 cycling heifers were conducted to evaluate the luteolytic activity of a synthetic prostaglandin, AY 24366, and PGF2alpha. Activity was assessed by the decline in progesterone level of peripheral blood and occurrence of estrus. Progesterone concentrations of jugular blood plasma were quantified by radioimmunoassay. In the first experiment, 36 heifers were treated during diestrus with AY 24366 (A-10mg intrauterine, B-30mg intramuscular and C-60mg im) or with PGF2alpha (D-5mg iu, E-15mg im and F-30mg im). Mean progesterone 0, 24 and 48 hours after treatment were A-6.33, 5.55 and 5.06; B-6.35, 2.79 and 3.92; C-5.23, 2.69 and 3.91; D-5.19, 1.50 and 1.51; E-4.69, 0.85 and 0.61; F-6.66, 0.80 and 0.48 ng/ml. Standing estrus was observed in 1, 1, 1, 4, 5 and 6 females in groups A, B, C, D, E and F respectively within 72 hours of treatment. PGF2alpha resulted in significantly (P less than 0.01) lower progesterone at 24 and 48 hours than AY 24366. However, in administration of the latter did significantly (P less than 0.05) lower progesterone at 24 hours. In the second trial six heifers were treated with either 120 or 180mg of AY 24366 im on day 12 of the cycle. Mean progesterone declined from 3.84 to 2.12 ng/ml (P less than 0.01) by 6 hours and to 1.59 ng/ml by 12 hours. Thereafter the decline was gradual and reached a level of 0.65 ng/ml at 72 hours. All six heifers showed standing estrus at 78 +/-2 hours and were inseminated. Two in each group conceived. Doses of 15mg PGF2alpha and 120mg AY 24366 were effective in causing luteal regression, however, the latter caused respiratory discomfort for 5 to 10 minutes post treatment.

Animals↗
PubMedDate not supplied

Anti-bull sperm monoclonal antibodies: I. Identification of major antigenic domains of bull sperm and manifestation of interspecies cross-reactivity.

The overall objective of this series of experiments is to generate immunological markers that may elucidate bull sperm surface changes in vitro. Here we report the initial experiments of the study, involving the production and characterization of monoclonal antibodies (mAbs) again bull sperm. BALB/c mice were immunized with phosphate-buffered saline (PBS)-washed whole bull sperm, and their spleen cells were fused with NS-1 myeloma cells in two separate cell fusion experiments, resulting in the generation of 15 mAbs. The mAbs were specific to antigens of either the posterior tail or the head regions of bull sperm and detected five major domains of antigen localization in the bull sperm (apical crescent, equatorial band, principal acrosomal, whole head, and posterior tail). Eleven of the 13 head-specific mAbs recognized intra-acrosomal antigens, whereas 2 mAbs recognized antigens that were localized in the plasma membrane. One mAb specific to the tail region was of the IgM class; the remaining 14 mAbs were of the IgG class. They were all sperm specific, with no cross-reactivity to bovine oocytes or to any of the 12 bovine somatic tissues tested. The mAbs were not species specific, however, because 11, 10, 2, and 1 of the 15 mAbs cross-reacted with sheep, pig, mouse, and human sperm, respectively. None of the mAbs cross-reacted with rooster sperm. The cognate antigens of the 11 tested mAbs were of testicular origin, but several of them showed enhanced binding to epididymal sperm. In western blot analysis, 3 of the 13 mAbs tested identified more than one protein band (40-200 kDa). Seven others recognized proteins of > or = 200 kDa, whereas three mAbs recognized no proteins.

Animals↗
PubMedDate not supplied

Anti-bull sperm monoclonal antibodies: II. Binding changes during capacitation and influence on sperm-zona interactions in vitro.

Anti-bull sperm monoclonal antibodies (mAbs), generated against intra-acrosomal and surface antigens, were evaluated for their functional significance. In experiment I, the influence of mAbs on the bovine sperm-oocyte interaction in vitro was tested on a total of 493 oocytes in either three or four replicate trials. Although the number of sperm bound per zona increased significantly over untreated control samples (23.6 +/- 5.6 vs. 10.0 + 2.4, mean +/- standard error [SE]; P < 0.001) in the presence of one surface-reacting mAb, other mAbs had no effect. Experiment II was designed to determine if the mAbs would detect capacitation-related changes of bull sperm in vitro. Bull sperm were incubated in capacitation medium (supplemented Tyrode's medium [TALP] plus 10 micrograms/ml heparin) for up to 4.5 hours. At 0 and at 4 hours, mAbs in hybridoma culture supernatant were incubated for 30 minutes with sperm, labeled with fluorescein isothiocyanate (FITC)-conjugated secondary antibody, and processed for indirect immunofluorescence assay. Four mAbs specific to intra-acrosomal antigens exhibited a time-dependent increase (P < 0.05) in binding to bull sperm incubated under capacitation conditions. In contrast, the binding of the mAbs specific to surface antigens significantly decreased (P < 0.05) after 4 hours in the presence of heparin. Sperm viability did not change during the 4-hour period. In experiment III, mAbs specific to intra-acrosomal antigens were evaluated to assess bull sperm acrosomal status following lysophosphatidylcholine-induced acrosome reaction. A significant decrease (P < 0.01) in mAb binding following the induced acrosome reaction was observed with all the mAbs; it was highly correlated (r > or = 0.85; P < 0.01) with Pisum sativum agglutinin binding and Giemsa staining. The results suggest that some of the mAbs are potential biological markers for bull sperm surface changes associated with capacitation and the acrosome reaction in vitro.

Acrosome↗