PubMed Health⌕ Search

Biomedical subjects

F Khamsi

Publications and source records attributed to F Khamsi.

25 records · Page 2Linked to original sources
PubMed1993

Human menopausal gonadotropin during in vitro maturation of human oocytes retrieved from small follicles enhances in vitro fertilization and cleavage rates.

OBJECTIVES: To compare the IVF rates of oocytes retrieved from small follicles (< 2 mL in volume) with those of oocytes retrieved from large follicles and to test the effect of adding gonadotropins to the IVF medium on the fertilization rates of oocytes from small follicles. DESIGN: Oocytes were retrieved with endovaginal ultrasound (US) guidance from patients undergoing infertility treatment in our IVF program. Oocytes were grouped according to the volume of the originating follicle and subjected to our routine procedure for IVF. HMG was added to the IVF medium for some of the oocytes from small follicles. SETTING: Toronto Fertility and Sterility Institute is affiliated with the University of Western Ontario and University of Toronto and is equipped for RIA, endovaginal US monitoring and oocyte retrieval, and for processing and culturing gametes and embryos. PATIENTS: Infertile patients admitted to our IVF program. INTERVENTIONS: Patients underwent ovarian stimulation with hMG before oocyte retrieval. No other interventions were introduced to the processing and culturing the gametes and embryos except the addition of hMG to the medium of some of the small follicle-originated oocytes with the informed consent from the patients. MAIN OUTCOME MEASURES: Rates of fertilization, cleavage of the fertilized embryos before replacement, and meiotic status of some of the oocytes from small follicles. RESULTS: Most of the oocytes from small follicles did not complete the first meiotic division; they had low rates of fertilization and cleavage compared with oocytes from large follicles, and these rates were improved by the addition of hMG to the IVF medium. CONCLUSIONS: Oocytes from small follicles are probably less mature and require a more physiological environment to achieve normal rates of fertilization and cleavage.

Adult↗
PubMed1992

Release of tissue-type plasminogen activator by activated rat eggs and its possible role in the zona reaction.

The resumption of meiosis results in synthesis of tissue-type plasminogen activator (tPA) in the rat and mouse oocytes (Haurte et al., Cell 43:551-558, 1985). The present study demonstrates that freshly ovulated rat oocytes released their tPA into the surrounding medium upon in vitro activation by sperm penetration or treatment with a calcium ionophore. The presence of a neutralizing monoclonal anti-tPA antibody during in vitro activation by the calcium ionophore inhibited the activation-induced zona hardening and also preserved the ability of the oocyte to be penetrated by sperm subsequent to activation. Rat oocytes undergo zona hardening during in vitro maturation in the absence of serum, presumably as a result of spontaneous cortical granule release, based on findings in mice and hamsters. In the present study, the anti-tPA antibody prevented the zona hardening and enhanced partition by spermatozoa of rat oocytes that were matured in vitro without serum. Collectively, the observations reported have suggest a possible role of tPA released during the cortical granule reaction in the zona reaction, which contributes to the block to polyspermy.

Animals↗
PubMed1992

Cushing's syndrome associated with ectopic corticotropin production and small-cell lung cancer.

PURPOSE: This study was undertaken to review the clinical and laboratory features and response to treatment of patients with Cushing's syndrome associated with ectopic corticotropin (adrenocorticotropic hormone; ACTH) production and small-cell lung cancer (SCLC). PATIENTS AND METHODS: We undertook a retrospective chart review of 545 patients with SCLC seen at Toronto General Hospital between 1980 and 1990 and identified 23 patients (4.5%) with Cushing's syndrome and ectopic ACTH production. RESULTS: There were 17 male and six female patients, with a median age of 60 years. The syndrome was diagnosed at the time of initial presentation of SCLC in 13 patients and at relapse in 10 patients. Seven patients had limited disease and 16 had extensive disease at their initial diagnosis of SCLC, but 20 of 23 had extensive disease at the time of diagnosis of Cushing's syndrome. Ten patients had bone marrow involvement. The most frequent physical findings included edema (83%) and proximal myopathy (61%). All patients had elevated plasma and urinary free cortisol levels; 22 had a hypokalemic alkalosis, and 13 had hyperglycemia. Only one patient had a normal ACTH level. The response rate (complete plus partial) to chemotherapy for patients who had the syndrome diagnosed at initial presentation of SCLC was only 46%, and their median survival was only 3.57 months. Only two patients achieved complete normalization of all hormone parameters, and neither experienced hormone relapse at the time of SCLC relapse. Complications of therapy included gastrointestinal (GI) ulceration (six patients), GI bleeding (four), perforation of a duodenal ulcer (one), pneumonia (10), septic shock (three), and fungal infections (five). CONCLUSION: Ectopic ACTH production is associated with a low response to chemotherapy, short survival, and a high rate of complication to therapy.

ACTH Syndrome, Ectopic↗
PubMed1991

Hormonal actions during oocyte maturation influence fertilization and early embryonic development.

On the basis of evidence just reviewed, the hormonal requirements during IVM of mammalian oocytes for fertilization and developmental competence may be summarized as follows: 1. Nuclear maturation occurs "spontaneously," without follicular factors or hormones, in all mammalian species. 2. Cumulus cells are necessary during nuclear maturation in culture for fertilization and developmental competence. Their effect is enhanced by the addition of serum or follicular fluid to the maturation medium. 3. FSH retards nuclear maturation, perhaps thereby enhancing subsequent developmental competence by allowing more time for cytoplasmic maturation to occur before fertilization. The effects of FSH are mediated, in part, by soluble factors from cumulus or granulosa cells. 4. FSH in vivo before culture or added in vitro to IVM culture media enhances fertilization and stimulates steroidogenesis (progesterone and estradiol) in cumulus cells. Blockade of steroidogenesis prevents the enhancing effect of FSH on fertilization. Progesterone can substitute for FSH in enhancing fertilization of rat oocytes. 5. Other hormones enhance beneficial effects of FSH, with some apparent species differences: a. Rat: Progesterone may mediate the FSH effect. b. Cow, rabbit: Estradiol enhances the beneficial effect of FSH. c. Rabbit: Prolactin further enhances the effects of estradiol and FSH. d. Human: No evidence is available on the possible synergism between steroids and gonadotropins in enhancing in vitro maturation. It is clear that further research is required to elucidate the mechanisms of action of all the hormones that have been observed to influence oocyte maturation, and to establish the physiologic significance of most of these, particularly in species other than laboratory rodents. Major benefits to animal production and human health are likely to accrue from such research.

Animals↗