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Biomedical subjects

K K Ahuja

Publications and source records attributed to K K Ahuja.

At least 37 records · Page 2Linked to original sources
PubMed1990

The management of predicted ovarian hyperstimulation involving gonadotropin-releasing hormone analog with elective cryopreservation of all pre-embryos.

Severe ovarian hyperstimulation syndrome complicates up to 6% of IVF treatment cycles. We have utilized our pre-embryo cryopreservation program to manage incipient ovarian hyperstimulation syndrome in an alternative way. Four women, who were at risk of developing ovarian hyperstimulation syndrome, underwent oocyte retrieval, but not embryo replacement. Instead, resulting pre-embryos were cryopreserved for future transfer. The four patients have since become pregnant. Three conceived after thawed embryo replacement cycles, and the fourth conceived spontaneously 1 month after the stimulation cycle. This approach offers maximum flexibility in the management of ovarian hyperstimulation syndrome.

Adult↗
PubMed1988

The value of IVF-ET in patients undergoing treatment by the GIFT procedure.

In patients undergoing the gamete intra-Fallopian transfer (GIFT) procedure, a prospective study was performed to establish the predictive value of attempting in-vitro fertilization (IVF) using extra oocytes obtained at laparoscopy and also the value of transferring the resulting embryo(s), in conjunction with GIFT, in the same treatment cycle. The GIFT procedure was performed in 50 treatment cycles involving 43 patients, of whom 20 have achieved clinical pregnancy with an overall success rate of 40% per treatment cycle. In 38 of these patients, one or more extra oocytes were available and an attempt was made in each case to fertilize them in vitro. When fertilization failed to occur in vitro, the chances of pregnancy were significantly reduced (9.1%). In patients for whom IVF of extra oocyte(s) was successful, there was no significant difference in the pregnancy rate whether embryo transfer was performed or not (54 and 57.1%, respectively). The success rate was also influenced by the number of oocytes collected rather than the number of oocytes/embryos transferred. Therefore these results suggest that IVF of extra oocytes is a good indicator of in-vivo fertilization and that if extra embryos are obtained they should be cryopreserved.

Adult↗
PubMed1988

The appearance of glycoconjugates associated with cortical granule release during mouse fertilization.

For the first time we have shown with appropriately labelled lectins that fucosyl- and sialyl-rich glycoconjugates are released into the perivitelline space of the mouse oocyte after activation by the fertilizing spermatozoon or artificial activation by the calcium ionophore A23187 or ethanol. The glycoconjugates show a punctate distribution over the oocyte surface except for the microvilli-free area overlying the second meiotic spindle from which they are absent. Their appearance in the perivitelline space is associated with the release of the cortical granule suggesting that they represent part of the cortical granule exudate. Soon after the glycoconjugates appear, they begin to aggregate. The process continues until the beginning of cytokinesis at first cleavage when a single large aggregate is found within the cleavage furrow. Most of the labelled glycoconjugates disappear by the late 2-cell stage and no evidence was found for their presence during the later preimplantation period. This technique is suitable for monitoring the kinetics of the cortical reaction in mammalian oocytes and investigating the importance of the glycoconjugates in early preimplantation period.

Animals↗
PubMed1987

An investigation using lectins of glycocomponents of mouse spermatozoa during capacitation and sperm-zona binding.

Ten different lectins conjugated to fluorescein isothiocyanate (FITC) were used to study the distribution of surface carbohydrates on mouse spermatozoa, and to monitor the possible changes of their distribution during capacitation in vitro and sperm-egg interaction. Most of the lectins gave a restricted pattern of binding to fixed or unfixed epididymal spermatozoa. Binding was highly specific because no staining occurred in the presence of appropriate monosaccharides. Binding of UEA I, DBA and Con A was unaffected by the type of fixative used, but it was influenced by mild centrifugation. While unwashed spermatozoa showed binding mainly over the acrosomal cap and equatorial or postacrosomal regions, spermatozoa washed by mild centrifugation showed a change in the staining of the equatorial segment. Binding of 5 different lectins to spermatozoa did not change during capacitation in vitro. In contrast, capacitated spermatozoa bound to the zona pellucida exhibited a UEA I binding pattern which was strikingly different from that of the capacitated but unbound spermatozoa. We conclude that glycocomponents of specific regions of mouse spermatozoa do not change dramatically during capacitation, but do alter significantly during binding to the zona pellucida.

Animals↗
PubMed1985

Carbohydrate determinants involved in mammalian fertilization.

During fertilization in mammals, the male and female gametes undergo a form of highly complex cell-cell recognition whereby a nonspecific initial binding is followed by a species-specific penetration of the zona pellucida. Recent data from many species have demonstrated the involvement of surface carbohydrates in regulating fertilization at both these stages. The potential benefits as well as drawbacks of three major techniques used so far are discussed, and the need for a cautious interpretation of the data is emphasized. During capacitation, the carbohydrate components of the entire surface of spermatozoa undergo striking changes which may be linked to the concurrent metabolic events within motile spermatozoa, leading to the appearance of egg-specific glycoconjugates in a time-dependent manner. A multiple set of glycoproteins on the sperm surface, possessing oligosaccharides synthesized by the lipid-linked pathway, are probably required during different stages of fertilization, including sperm-oocyte fusion. The oviductal glycosaminoglycans may also be involved in regulating the timing and species specificity of mammalian fertilization by masking the sperm receptor sites on the zona and triggering the physiological acrosome reaction. Future biochemical and high-resolution localization studies involving specific probes for surface glycoconjugates, glycosyltransferases, and hydrolytic enzymes should greatly aid our understanding not only of the role of the individual surface macromolecules but also of the surface domains to which they are localized.

Acrosome↗
PubMed1985

Augmentation of mitogen-induced proliferative responses by in vitro indomethacin in patients with acquired immune deficiency syndrome and AIDS-related complex.

The effect of indomethacin on mitogen-induced lymphocyte proliferative responses was studied in six normal heterosexual subjects and nine patients with the acquired immune deficiency syndrome (AIDS) and AIDS-related complex (ARC). Indomethacin enhanced only Con A-induced lymphocyte responses in six heterosexual men. In contrast, study of the cells from AIDS and ARC revealed that indomethacin enhanced PHA-induced lymphocyte proliferative responses from 52,600 counts/min to 70,900 counts/min (P less than 0.005) and 81,400 counts/min (P less than 0.001) at 0.1 and 1 microgram/ml. respectively and increased Con A-induced lymphoproliferation from 30,800 counts/min to 52,000 counts/min (P less than 0.01) at 0.1 microgram/mg and 51,1000 counts/min (P less than 0.005) at 1 microgram/ml. These results suggest that indomethacin enhanced mitogen-induced lymphoproliferative responses in vitro with cells from patients with AIDS and AIDS-related complex and may have therapeutic potential in some patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Successful pregnancies from the transfer of pronucleate embryos in an outpatient in vitro fertilization program.

Twenty-nine infertile women were given clomiphene citrate (100 mg/day, days 3 to 7), human menopausal gonadotropin (150 IU/day, days 7 to 12 or 13), and human chorionic gonadotropin (2000 IU) for the induction of ovulation. Eggs were collected by laparoscopy and preincubated for 6 hours before being cultured with spermatozoa for fertilization. Approximately 16 to 18 hours after insemination, the eggs that showed two pronuclei were transferred to the patient's uterus. As confirmed by the ultrasonic appearance of a gestational sac, six women who received pronucleate embryos became pregnant, and three pregnancies resulted in normal full-term deliveries. These results confirm that, unlike requirements for most laboratory and farm animals, the requirements of synchrony between the preimplantation human uterus and developing embryos are not very stringent. In vitro fertilization treatment procedures can thus be made simpler by the transfer of embryos at the pronucleate stage.

Adult↗
PubMed1985

Involvement of sperm sulphatases in early sperm-zona interactions in the hamster.

Sulphatase preparations from Abalone entrails, the limpet Patella vulgata and ox liver, as well as artificial substrates for these enzymes, were used in the hamster in vitro fertilization system to study the possible roles of sperm sulphatases in sperm-zona pellucida interactions. p-nitrophenyl sulphate, p-nitrocatechol sulphate, ascorbate 2-sulphate, as well as D-glucopyranose and D-galactopyranose, both sulphated at the 3, 4 or 6 position but not the 2 position, inhibited fertilization in a dose-dependent manner. Sperm-egg fusion was not inhibited by the substrates used and eggs pre-treated with sulphates could readily be fertilized. Sperm motility and therefore viability was unaffected by inhibitory concentrations of substrates as determined by rhodamine 123 labelling of motile spermatozoa. Acrosomal integrity of rhodamine-labelled spermatozoa was assessed and found to be unaffected by inhibitory levels of substrates. Fertilization was inhibited by high concentrations of the two molluscan sulphatases but not by purified ox liver sulphatase. Pre-treatment of eggs with these enzymes did not prevent fertilization. Long-term exposure of hamster oocytes to N-acetylhexosaminidase or limpet sulphatase caused thinning and distension of the zona pellucida but these changes were not observed with the ox liver sulphatase. The results suggest that a glycosulphatase is probably released from hamster spermatozoa during sperm-egg adhesion and, or, penetration. If sperm-egg adhesion molecules are sulphated, the commercially available sulphatases would be unsuitable for their characterization.

Acrosome↗
PubMed1984

Lectin-coated agarose beads in the investigation of sperm capacitation in the hamster.

Sperm surface changes during in vitro capacitation were examined with the help of an assay system using lectin-coated agarose beads. The nature and intensity of binding of epididymal spermatozoa to beads depended entirely on the particular stage of capacitation and the type of lectin attached to the bead surface. Fresh epididymal spermatozoa bound readily to beads coated with Con A, LCA, WGA, and PNA, but not with seven other lectins. During capacitation there was a constant decline in sperm binding to beads, and spermatozoa cultured for 4-5 hr bound only to those coated with Con A. A dramatic increase in sperm binding to Con A-coated agarose beads occurred between 4.5 and 5 hr, when large numbers of hyperactivated spermatozoa adhered, predominantly through their flagellae, to form large clumps on the beads. The clumping of spermatozoa on Con A-coated beads was enhanced in the presence of stimulators of capacitation (i.e., taurine, hypotaurine, and phosphodiesterase inhibitors) and was suppressed in the presence of various metabolic inhibitors (i.e., sodium azide and local anesthetics). The implications of these results are that the carbohydrate components of the entire surface of spermatozoa undergo striking changes during capacitation, and a close relationship may exist between the sperm surface and the metabolic changes occurring within capacitating spermatozoa. Sperm-bead binding assays are clearly able to recognize surface changes in asynchronous populations of motile spermatozoa and, due to their simplicity and speed, should prove to be valuable in gaining a greater understanding of the biochemistry of sperm capacitation.

Animals↗
PubMed1983

Probable asymmetry in the organization of components of the hamster zona pellucida.

The distribution of the sperm-, lectin- and antibody-binding components was examined on isolated fragments of the hamster zona pellucida. In all three studies, binding was much stronger on the outer than on the inner surface of the zona pellucida. Fab antibody-binding sites were different from those for various lectins since there appeared to be no competition for binding. Multiple components are obviously exposed on the surfaces of the zona pellucida because the sperm receptor sites are also inaccessible to Fab fragments. We conclude that although the components may be present throughout the zona they are asymmetrically arranged in relation to both surfaces. Microdisc PAGE of zonae from ovulated eggs revealed three major components of molecular weight 240 000, 150 000 and 80 000. These are probably glycoproteins and thus resemble the glycoprotein composition of the mouse zona.

Animals↗
PubMed1982

In-vitro inhibition of the block to polyspermy of hamster eggs by tertiary amine local anaesthetics.

When freshly ovulated hamster eggs (16 h after hCG) were incubated at 37 degrees C in the presence of local anaesthetics, the extrusion of the second polar body was inhibited in differing proportions of eggs, depending on the concentration of drug and the age of eggs. Insemination of procaine (3 X 10(-3) M)- and tetracaine (2 X 10(-4) M)-treated eggs with capacitated spermatozoa in vitro resulted in approximately 80% of eggs showing multiple penetration compared with approximately 20% for controls, indicating that local anaesthetics interfere with the block to polyspermy in the egg. This effect was reversed by raising the concentration of Ca2+, but not Mg2+, during treatment with the drug or washing the drug-loaded eggs in Ca2+-containing medium. When the treatment of eggs was carried out at 4 degrees C, no such inhibition of the block to polyspermy was observed. The extrusion of cortical granules was delayed by procaine, although the rate of fertilization was not affected. The results provide evidence to support the belief that the initiation of the block to polyspermy in the hamster is dependent on Ca2+-triggered release of cortical granules.

Animals↗
PubMed1981

Investigation of sperm receptors in the hamster zona pellucida by using univalent (Fab) antibodies to hamster ovary.

An antiserum raised in rabbits against hamster ovaries was digested with papain to obtain the univalent (Fab) fragments. The anti-zona pellucida activity of this preparation was monitored by a direct fluorescence test and by an indirect precipitation test. In contrast to the effects produced by immune gamma-globins on the zona pellucida, the immune Fab antibodies failed to form a precipitate layer on the zona pellucida and did not inhibit fertilization in vitro. Immune Fab antibodies also failed to overcome the fertilization-inhibiting effects of zona sperma receptors in solution. It is concluded that the sperm receptors, which are thought to be essential for sperm attachment to the zona pellucida and consequently for fertilization, have little or no antigenicity.

Animals↗
PubMed1977

Carcinoma of the breast with multinucleated reactive stromal giant cells. A light and electron microscopic study of two cases.

Two unusual carcinomas of the breast are described, containing nests of infiltrating neoplasm situated within stromal lacunar spaces, and surrounded by numerous benign appearing multinucleated giant cells. Within the stroma, there was extensive hemorrhage, hemosiderin pigment deposition, and large numbers of mononucleated inflammatory cells. The morphology of both tumors resembled the giant cell tumor of bone. Although a similar giant cell reaction has recently been described in association with a uterine leiomyosarcoma, we are aware of only two other examples of this entity in the breast, both reported over 40 years ago in the French literature. This is the first report in which electron microscopy confirmed the benign histiocytic nature of the giant cells. These cells had many of the ultrastructural features of multinucleated giant cells described in tissue culture, skeletal osteoclastomas, and foreign body granulomas. We propose that the giant cells arise from fusion of mononucleated stromal cells, and most likely are reactive histiocytic elements which are in some way related to the tumor cell nests. Further studies of these unusual neoplasms are needed to determine if the giant cell reaction in any way affects the prognosis of the patient.

Adult↗