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Biomedical subjects

R D Lambert

Publications and source records attributed to R D Lambert.

51 records · Page 3Linked to original sources
PubMed1983

[Extracorporal fertilization of the human oocyte and transfer of the embryo: consideration of technics and ethics].

In vitro fertilization of human oocytes is successful only when several techniques are perfectly mastered. Accurate prediction of imminent ovulation by rapid radioimmunoassay of luteinizing hormone in the plasma, suitable hormonal treatment or ultrasonography, or a combination of these, leads to the recovery of mature oocytes. Factors such as suction strength and bore size of the aspiration needle may interfere with the recovery of follicular oocytes during endoscopy. Capacitation of the spermatozoa, the most critical part of the whole process, requires the presence of serum or serum albumin. Fertilization and embryonic development in vitro occur in well defined experimental conditions. However, in spite of all the precautions currently taken, the rate of success, in terms of pregnancies continued to term, is still much lower than that observed under natural conditions. Much better results will likely be obtained in the near future. The literature suggests that in vitro fertilization and embryo transfer do not have any harmful physical effects on the offspring. Moreover, the laws of biology suggest that in vitro fertilization of human oocytes does not raise any ethical problem with regard to the potential offspring. However, it is extremely difficult to identify ethical problems related to the influence of the technique of in vitro fertilization on the evolution of man and human society.

Embryo Transfer↗
PubMed1983

Prediction of bovine ovulation by a rapid radioimmunoassay for plasma LH.

A commonly used and specific plasma LH radioimmunoassay was modified to provide reliable results for cow LH concentrations in blood within 4-5 h. Blood samples were collected at 2- or 4-h intervals from at least 24 h before the expected oestrus until after its onset. Thereafter, samples were collected at intervals of 2 or 4 days until the next oestrus. For the assay, the antigen-antibody reaction took place during a 2-h incubation at 37 degrees C. The immune complex was precipitated by addition of rabbit anti-gamma-globulin and polyethylene glycol followed by an incubation at 22 degrees C for 30 min. The coefficient of variation between this assay and the standard assay was less than 15%. From a study of 25 cycles from 12 animals, we obtained intervals of congruent to 27.3 h between the beginning of the LH peak and ovulation and congruent to 17.5 h between the end of the peak and ovulation. This modified technique can be used to predict rapidly and precisely the time of ovulation in cattle.

Animals↗
PubMed1983

Effect of the products of ovulation on in vitro fertilization and sperm motility in the rabbit.

Different concentrations of rabbit or bovine follicular fluid were added to a defined medium or to rabbit oestrous oviduct fluid containing 13 hours in utero incubated sperm. With increasing concentration of follicular fluid, the percentage of fertilization was progressively and significantly lower than in oestrous tubal secretions or Brackett's medium, alone or containing up to 5% of follicular fluid. Utilization of ova, with or without cumulus clot, to the fertilization media, had no significant effect on fertilization of rabbit eggs. Both kinds of follicular fluid used did inhibit the motility of capacitated sperm.

Animals↗
PubMed1981

Plaque assay for Ebola virus.

A plaque assay for Ebola virus is reported. The procedure has real potential for future research, although it is less sensitive than indirect fluorescent-antibody and mouse inoculation tests.

Animals↗
PubMed1981

[Effects of uterine secretions on embryonic development].

Rabbit embryos at the stage of one-cell and morula were incubated in uterine secretions from rat. The uterine fluid was aspirated from uterus of freshly sacrificed estrus animals. We obtained a very good development of the morulas (mean of the maximum diameter : 0.79 +/- 0.02 mm); however only 35% of the one cell rabbit embryos reached the stage of 16 cells. This consequently suggest a uterine tropism in the rats similar to that previously found for the rabbit.

Animals↗
PubMed1979

[Confirmation of the presence of uteroglobin in tubal secretions].

The acrylamide gel electrophoresis of rabbit serum, of rabbit tubal secretions at the oestrus stage (STO) and at the luteal stage (STL), followed by immunodiffusion with anti-serum, was done to detect any tubal proteins which were not found in the rabbit serum. The anti-rabbit STO goat anti-serum was absorbed with rabbit plasma in order to purify antibodies to proteins found specifically in tubal secretions. This technique revealed the presence of a protein (STx) in STO and STL but not in the rabbit serum. The electrophoretic migration (Rf = 0.72) of the tubal protein (STx) is similar to uteroglobin (Rf = 0.74). The tubal protein was detected immunologically only in tissues where uteroglobin had been found by other workers: lungs, semen, Fallopian tubes and uterine secretions (5 days post-ovulation); further more a complete identity for the precipitating line existed between these extracts. These results corroborate the presence of uteroglobin or of a very similar protein in oestrus of luteal tubal secretions and in some other rabbit tissues.

Animals↗
PubMed1978

[Effect of coitus on sperm transport and fertilization in rabbits].

The number of spermatozoa into the Fallopian tubes and levels of in vivo fertilization were measured following different treatment. The results show that copulation by the artificially inseminated animal has a strong influence on the transport of the rabbit spermatozoa and "in vitro" fertilization. This constitutes some more evidence about the physiological role played by the utero-tubal junction.

Animals↗
PubMed1975

In vitro fertilization of rabbit eggs in oviduct secretions from different days before and after ovulation.

In vitro fertilization of rabbit eggs in oviduct secretions has been studied through different days of the psudopregnant cycle. The appearance of the pronuclei and cleavage into two cells, which were the criteria of fertilization, occurred significantly less frequently when in vitro fertilization was attempted in the oviduct secretions obtained during the estrous (preovulatory) period of the cycle than it was in the secretions obtained during pseudopregnancy or in Brackett's medium plus 20% heated rabbit blood serum. Whether fertilization was attempted in ampulla secretions or in whole oviduct secretions had no effect on the success rate. The effects of oviduct secretions from the estrous period of the cycle is probably due mainly to an effect on the egg, involving the very first development processes during and after fertilization.

Animals↗