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Biomedical subjects

I Khan

Publications and source records attributed to I Khan.

At least 127 records · Page 7Linked to original sources
PubMed1991

In-vitro fertilization, gamete- or zygote intra-fallopian transfer for the treatment of male infertility.

This retrospective study compares in-vitro fertilization and embryo transfer (IVF-ET), gamete intra-Fallopian (GIFT) and zygote intra-Fallopian transfer (ZIFT) for the treatment of male infertility in 266 couples (n = 318 cycles). The IVF-ET technique revealed a total pregnancy rate of 14.1% per cycle and 29.1% per transfer. The conception rate with GIFT was 17.8%; an abortion rate of 50% was noted. The ZIFT procedure scored a 20.9% total pregnancy rate per cycle and 33.3% per transfer. The cumulative take home baby rates per couple for IVF-ET, GIFT and ZIFT were 13.5, 7.0 and 20.0%, respectively.

Adult↗
PubMed1991

Calcium-calmodulin and calcium-phospholipid dependent phosphorylation of membranous fraction proteins related to the tropic regulation by estradiol in the corpus luteum.

Estradiol assumes a major role in the regulation of growth, vascularization, and progesterone synthesis in the midpregnant rat corpus luteum. To explore whether molecular events triggered by estradiol could be mediated, at least in part, by protein phosphorylation, we investigated whether estradiol treatment in vivo affects endogenous luteal protein phosphorylation systems detectable in vitro. Luteal nuclear, mitochondrial, and microsomal fractions were obtained by differential centrifugation from rats hypophysectomized and hysterectomized on day 12 of pregnancy and treated with or without estradiol for 72 h. Using [gamma-32P]ATP as phosphate donor, proteins were phosphorylated in the presence or absence of either calcium (Ca), Ca plus calmodulin, or Ca plus phospholipid. Phosphoproteins were separated by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and visualized by autoradiography. The Coomassie blue stained proteins and phosphoprotein profiles were markedly different in the various fractions. Estradiol treatment in vivo caused an increase in the basal endogenous phosphorylation of several proteins in vitro. It also substantially enhanced the protein kinase C (PKC) and Ca-calmodulin kinase-dependent phosphorylation of selected proteins in subcellular fractions. The Ca-calmodulin kinase catalyzed phosphorylation of microsomal 56 and 60 kilodalton (kDa) proteins was remarkably increased by estradiol. Proteins (56 and 60 kDa) were also phosphorylated when Ca-calmodulin was added to the nuclear fraction, however, this phosphorylation did not appear to be affected by estradiol treatment. A major PKC substrate in the nuclear fraction was an 80 kDa protein whose phosphorylation was increased remarkably by estradiol treatment. In the mitochondrial fraction the most striking effect of estradiol was a marked increase in PKC-mediated phosphate transfer into a 76 kDa substrate. To determine whether estradiol action on protein phosphorylation was related to its tropic effect in the corpus luteum, the hormone was administered to day 10 hypophysectomized and hysterectomized pregnant rats. In this rat model, where estradiol has no stimulatory effect on either luteal steroidogenesis or growth, neither endogenous nor kinase-mediated phosphorylation was affected by this steroid. In summary, the present investigation has revealed that in vivo treatment with estradiol affects the PKC and the Ca-calmodulin dependent in vitro phosphorylation of selected proteins localized in different subcellular compartments and further suggests that phosphorylation systems are potential control points for estradiol regulation of rat corpus luteum function.

Animals↗
PubMed1991

Expression, action, and steroidal regulation of insulin-like growth factor-I (IGF-I) and IGF-I receptor in the rat corpus luteum: their differential role in the two cell populations forming the corpus luteum.

The overall aim of this investigation was to examine the expression and steroidal regulation of insulin-like growth factor-I (IGF-I) and the IGF-I receptor in the rat corpus luteum and to examine the specificity of IGF-I action in the two luteal cell populations. We first examined whether the corpus luteum expresses the IGF-I and IGF-I receptor genes. Using a solution hybridization/RNase protection assay, IGF-I and IGF-I receptor mRNAs were represented by protected bands 224 and 265 bases in length, respectively. In addition, Northern blot analysis showed that, as in liver, rat IGF-I and IGF-I receptor cDNAs hybridized with 7.5-, 1.8-, and 0.8- to 1.2-kilobase transcripts and an 11-kilobase transcript, respectively. Both IGF-I and IGF-I receptor mRNAs were detected on all days of pregnancy tested (days 5-21). Since the rat corpus luteum increases remarkably in size and steroidogenic capacity at midpregnancy due to estradiol stimulation, we determined whether these developmental changes are accompanied by an increased expression of the IGF-I and/or IGF-I receptor genes. Total RNA was isolated from corpora lutea of day 12 hypophysectomized-hysterectomized rats treated with or without estradiol for 3 days. Estradiol caused a clear and marked reduction in IGF-I and IGF-I receptor mRNA. [125I]IGF-I bound with high specificity and affinity to luteal cell membranes. Large and small cell populations forming corpora lutea of day 3 and 14 pregnant rats were separated by elutriation and used for the determination of binding activity and for cell culture, respectively. IGF-I receptors were found to be localized principally in the large luteal cell population. The small luteal cells had approximately 6.5-fold less IGF-I-binding activity. The difference in binding activity in both cell populations was reflected in the ability of both cell types to respond to IGF-I. IGF-I (25 ng/ml) had a profound effect on the production of progesterone by the large luteal cells. No stimulatory effect of IGF-I on the small luteal cells was observed. Addition of estradiol (10 ng/ml) to the cell culture remarkably enhanced IGF-I stimulation of progesterone biosynthesis by the large luteal cells. In summary, the results of this investigation have revealed that the corpus luteum of the pregnant rat is a major site of expression of both the IGF-I and IGF-I receptor genes.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Human serum albumin versus serum: a comparative study on embryo transfer medium.

OBJECTIVE: This study has examined the efficacy of human albumin as a replacement for serum in embryo transfer (ET) medium. DESIGN: In a prospective, randomized study, 224 cycles were analyzed. Patients were randomly divided into three groups: in group A, embryos were transferred in 75% serum; in group B, in 8% serum; and in group C, 2.25% human serum albumin (HSA). SETTING: All the ETs were performed in patients from the in vitro fertilization program of the Center for Reproductive Medicine, Vrije Universiteit Brussel, Belgium. PATIENTS, PARTICIPANTS: In 194 patients, 224 ETs were performed. The patients were selected when they had at least one good-quality embryo. INTERVENTIONS: None. MAIN OUTCOME MEASURE(S): Use of albumin in culture medium resulted in higher pregnancy rates (PRs). To further simplify the procedure, albumin was also used in ET medium. RESULTS: An overall PR of 43% in group A, 27% in group B, and 36% in group C was achieved. No significant difference was observed in PRs between three different transfer media. CONCLUSIONS: We conclude that HSA is a safe and suitable replacement for serum, both in embryo culture and in the transfer medium.

Adult↗
PubMed1990

Abundance of sarcoplasmic reticulum calcium pump isoforms in stomach and cardiac muscles.

Rabbit stomach smooth muscle contains mRNA for an internal Ca2+ pump identical in sequence to that reported for rabbit uterus [Lytton, Zarain-Herzberg, Periasamy & MacLennan (198) J. Biol. Chem. 264, 7059-7065]. This is an alternatively spliced form (Is) of the cardiac muscle sarcoplasmic reticulum Ca2+ pump (Ic). The splicing results in replacement of the last 4 amino acids (Ala-Ile-Leu-Glu) present in Ic by 49 amino acids and by a different 3'-non-coding region. Using cDNA probes against the conserved and the alternatively spliced regions, we determined that poly(A+) RNA isolated from rabbit stomach smooth muscle did not contain any transcripts for Ic. The poly(A+) RNA from cardiac muscle contained transcripts mostly for Ic, but also some for Is. The abundance of the Ca2(+)-pump transcripts as measured by the binding of a cDNA probe against the conserved region to poly(A+) RNA was 6-8 times higher in cardiac than in smooth muscle. The amount of the corresponding pump protein, measured using two antibodies, was 60-80 times higher in cardiac membranes than in smooth muscle membranes. Thus the protein-to-transcript level was approx. 10-fold higher in the cardiac muscle. We conclude that the regulation of the abundance of this protein occurs at steps leading to the formation of the mature mRNA for the two splices, which may differ in their translation efficiency.

Animals↗
PubMed1990

Comparison between human serum and Albuminar-20 (TM) supplement for in-vitro fertilization.

Patient or fetal cord serum is commonly used as a protein supplement to culture media used in in-vitro fertilization (IVF). To eliminate the variability and possible hazards related to the use of human serum, a well-defined protein supplement, Albuminar-20 (Armour Pharmaceutical Cy) was evaluated as a substitute for serum. Prior to its application in the human, Earle's culture media supplemented with 0.5% (w/v) bovine serum albumin, 8% (v/v) decomplemented patient serum or 2.25% (v/v) Albuminar-20 were compared in a mouse bioassay. For the three different conditions, the percentages of blastocysts formed after 120 h in-vitro culture were respectively 91.2, 85.2 and 87.8% (NS). In the human IVF, a controlled comparison was performed from October to December 1988, between Earle's medium supplemented with patients' serum or Albuminar-20. When oocytes and spermatozoa were cultured in these two media, the fertilization rates were similar, 58.9% in human serum versus 59.4% in Albuminar-20. After further culture, the morphological quality of the cleaved embryos was better in the embryos cultured in Albuminar-20. The higher pregnancy rate in Albuminar-20 was correlated with the better morphological appearance of the embryos and their more advanced cleavage stage at the time of transfer. Therefore, Albuminar-20 can be considered as a suitable protein supplement in human IVF.

Animals↗
PubMed1990

Identification and characterization of an abundant phosphoprotein specific to the large luteal cell.

An abundant protein with a relative mol wt of 32K present specifically in the large cells of the pregnant rat corpus luteum has been identified. Separation of large and small luteal cells by elutriation, followed by protein analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), have revealed that the 32K protein was present as a major protein in the large luteal cells but was practically absent in the small cell population. This protein appears to be highly tissue and cell specific and resolves into three protein species by two-dimensional SDS-PAGE with the major protein having an isoelectric point (pI) greater than or equal to 8.5. It was not detected in preantral follicles or placentas of the same pregnant rats, or in any other tissue examined. After subcellular fractionation, the 32K protein(s) was found in the particulate fraction and was localized principally in the microsomal compartment. Autoradiographic analysis of 35S-amino acid-labeled tissue demonstrated that the 32K protein(s) is synthesized in the corpus luteum. When particulate fractions from small and large cells were incubated in the presence of [gamma-32P]ATP followed by SDS-PAGE, phosphorylation of the 32K protein was apparent. Phosphorylation of this protein was not enhanced by the addition of cofactors for cAMP, Ca2(+)-calmodulin- or Ca2(+)-phospholipid-dependent kinases. Experimental inhibition of steroidogenesis with amino-glutethimide caused a remarkable reduction in the luteal content of this 32K protein whereas estradiol and human CG treatment increased its content. In summary, we have discovered and partially characterized a unique 32K protein(s) which is expressed and phosphorylated only in large luteal cells of the corpus luteum. This protein(s), which is regulated by estradiol formed locally, may serve as a powerful marker for both the large luteal cell and estrogen action in the corpus luteum.

Animals↗
PubMed1990

Mechanism for control of hydroxymethylglutaryl-coenzyme A reductase and cytochrome P-450 side chain cleavage message and enzyme in the corpus luteum.

The present study was undertaken to investigate the mechanism for control of hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase and cytochrome P-450 side chain cleavage (P-450scc), enzymes involved in the synthesis and processing of cholesterol in the corpus luteum of pregnant rats. The role of sterol and estradiol were investigated by administering 4-aminopyrazolo-[3,4d]pyrimidine (4-APP), aminoglutethimide and/or estradiol to day 12 hypophysectomized-hysterectomized pregnant rats. Estradiol treatment markedly increased mRNA levels of HMG-CoA reductase in the corpus luteum. This stimulatory effect of estradiol was specific for the reductase since the mRNA for luteal P-450scc did not increase following estradiol treatment. To determine whether estradiol's action on HMG-CoA reductase mRNA was mediated by changes in cellular free cholesterol, the separate and combined action of estradiol and either 4-APP or aminoglutethimide on both sterol content and HMG-CoA reductase expression was examined. The estradiol induced rise in HMG-CoA reductase was not accompanied by a decrease in luteal cholesterol. 4-APP treatment depleted cholesterol in the corpus luteum and induced a greater increase in HMG-CoA reductase mRNA than estradiol. Combined treatment with estradiol and 4-APP resulted in a synergistic increase in HMG-CoA reductase mRNA despite the fact that estradiol did not further reduce the 4-APP induced decrease in luteal sterol content. This indicates that luteal cells possess an estradiol-mediated mechanism for up-regulation of HMG-CoA reductase gene expression which is distinct from the cholesterol negative feedback regulation. However, estradiol stimulation of HMG-CoA reductase was totally inhibited when sterol content was elevated by aminoglutethimide, suggesting that estradiol stimulation of HMG-CoA reductase expression is not sufficient to overcome the negative regulatory effect of cholesterol. In contrast to HMG-CoA reductase mRNA which appears to be controlled by sterol and estradiol, P-450scc mRNA levels remained constant in corpora lutea despite wide changes in sterol and steroid content induced by either 4-APP, aminoglutethimide or estradiol treatment. However, interestingly, aminoglutethimide increased substantially the content of P-450scc protein. This increase in P-450scc enzyme was not due to a greater amount of translatable message since similar levels of immunoprecipitable 35S-P-450scc were translated in vitro from luteal mRNA of rats treated with or without aminoglutethimide. In summary, results of this investigation have revealed that the expression of HMG-CoA reductase and cytochrome P-450scc are controlled by totally different mechanisms in the rat corpus luteum.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenine↗
PubMed1990

In vitro and in vivo effects of the triazolobenzodiazepine alprazolam on hypothalamic-pituitary-adrenal function: pharmacological and clinical implications.

We report here a study of the effects of alprazolam on in vivo pituitary-adrenal function in jacketed nonrestrained nonhuman primates and on in vitro CRH release from rat hypothalami and ACTH release from rat dispersed anterior pituicytes. We undertook this study because alprazolam is the only benzodiazepine effective in treating both major depressive and anxiety disorders, and recent data suggest that the hypercortisolism of major depression reflects hypersecretion of CRH. Moreover, the intracerebroventricular administration of CRH can reproduce many of the components of the symptom complex of major depression, including not only hypercortisolism, but also hypothalamic hypogonadism, decreased libido, anorexia, and intense anxiety. As a comparison, we also assessed the effects of diazepam on in vitro CRH release, because in contrast to alprazolam, diazepam is effective in anxiety states but not in depression. Alprazolam (0.01-0.3 mg/kg, iv) produced a dose-dependent inhibition of both plasma ACTH and cortisol secretion in non-restrained adult male rhesus monkeys. Our in vitro studies showed that alprazolam significantly inhibited serotonin (5HT)-induced CRH release in a dose-dependent fashion (10(-10)-10(-5) M). Diazepam also inhibited 5HT-induced CRH release, but was 40 times less potent than alprazolam. Alprazolam was ineffective in blocking basal or CRH-induced ACTH release from rat dispersed anterior pituicytes, suggesting that its in vivo effects are through inhibition of CRH secretion. As expected, the inactive benzodiazepine ligand Ro 15-1788 inhibited the effects of alprazolam on 5HT-induced CRH release, but this occurred only at doses below 10(-7) M. Interestingly, when incubated alone in higher doses with our rat hypothalamic organ culture, Ro 15-1788, like alprazolam, produced a dose-dependent inhibition of 5HT-induced CRH release (10(-7)-10(-5) M), suggesting an agonistic action of Ro 15-1788 at the benzodiazepine receptor at higher concentrations. We conclude that alprazolam is capable of suppressing the primate pituitary-adrenal axis, and that this suppression most likely reflects suppression of the CRH neuron rather than of the pituitary corticotroph cell. We speculate that the enhanced capacity of alprazolam to suppress the CRH neuron relative to other benzodiazepines may contribute to its unique efficacy among this class of drugs in the treatment of major depression. The capacity of Ro 15-1788 to reverse alprazolam-induced suppression of the CRH neuron indicates that the effects of alprazolam are mediated at least in part via its interaction with the benzodiazepine component of the gamma-aminobutyric acidA macromolecular complex.

Adrenocorticotropic Hormone↗
PubMed1990

Induction and repression of specific estradiol sensitive proteins in the rat corpus luteum.

In the pregnant rat estradiol causes luteal cell hypertrophy and a dramatic increase in overall protein synthesis. The aim of this investigation was to determine whether estradiol induces the synthesis of specific proteins in luteal cell subcellular fractions and to examine estradiol-regulated translational products in order to identify a specific protein marker of estradiol action in the corpus luteum. Corpora lutea obtained from day 12 hypophysectomized-hysterectomized pregnant rats treated with or without estradiol (2 cm implant) for 3 days were incubated with Trans35S-label for 8 hours at 37 degrees C in an atmosphere of 95% O2 - 5% CO2. Nuclear, mitochondrial, microsomal and cytosolic subcellular compartments were obtained by differential centrifugation. RNA was extracted and translated using a rabbit reticulocyte lysate reaction mixture. Radiolabeled proteins were separated by SDS-PAGE, visualized by fluorography and quantified by densitometry. Estradiol-treatment significantly increased 35S-amino acid incorporation into luteal proteins. Specific estradiol-induced proteins within cellular fractions included mitochondrial 80, 50, and 32 x 10(-3) Mr proteins; microsomal 100, 80, 32 x 10(-3) Mr proteins; and cytosolic 80, 60, 50 and 14 x 10(-3) Mr proteins. Estradiol-treatment increased the secretion of two proteins (60 and 45 x 10(-3) Mr) while no major estradiol-induced proteins were noted in the nuclear fraction. In vitro translation of mRNA indicated that estradiol markedly enhances the message for a protein with apparent Mr 32 x 10(-3) Mr. The 32 x 10(-3) Mr translated protein appeared as the major estradiol-induced protein in mitochondrial and microsomal fractions. Estradiol also reduced the expression of a 38 x 10(-3) Mr protein (pI 7.0) in the cytosolic compartment. The major estradiol sensitive protein observed in luteal particulate and translation profiles was a 32 x 10(-3) Mr protein with a pI greater than or equal to 8.5. This protein may serve as a potential protein marker of estradiol action in the rat corpus luteum.

Animals↗
PubMed1990

A study of urolithiasis in North West Frontier Province of Pakistan.

Of 188 (144 renal, 29 bladder, 15 ureteric) stones analysed, 109 (58%) were pure calcium oxalate stones and in 177 (94%) calcium oxalate was the main component. The remaining were of mixed composition containing calcium phosphate, uric acid and calcium hydrogen phosphate. Serum calcium levels in 50 patients with pure calcium oxalate stones were normal. Majority of the cases (76%) came from the hilly areas of N.W.F.P.

Adult↗
PubMed1989

An 18-month survey of infertility treatment by in vitro fertilization, gamete and zygote intrafallopian transfer, and replacement of frozen-thawed embryos.

An 18-month survey of infertility treatment by in vitro fertilization (IVF) and related procedures at the Centre for Reproductive Medicine of the Vrije Universiteit Brussel is described. During this period, 1326 treatment cycles were started in patients with long-standing infertility and 1135 oocyte retrievals were performed in 771 different patients. IVF and embryo transfer (ET) after laparoscopic (N = 793) or ultrasonically guided (N = 342) ovum pickup, gamete intrafallopian transfer (GIFT; N = 284), or zygote intrafallopian transfer (ZIFT; N = 15) combined with IVF as well as the replacement of cryopreserved embryos yielded an overall pregnancy rate of 21.8% per started cycle. Echographic and laparoscopic oocyte retrieval gave similar results except for a higher fertilization rate after echographic-guided retrieval. For in vitro fertilization and embryo transfer an overall pregnancy rate of 26% per transfer was obtained. For GIFT and ZIFT the pregnancy rates were, respectively, 27.8 and 46.7% per replacement. For each procedure one-third of the pregnancies aborted. After the replacement of frozen and thawed embryos, during a natural cycle, a significantly lower fetal loss was observed.

Adult↗
PubMed1989

Assisted procreation in the presence of a positive direct mixed antiglobulin reaction test.

Twenty-five infertile couples in which the male had antisperm antibodies were treated by in vitro fertilization (IVF), zygote intrafallopian transfer, or gamete intrafallopian transfer in 38 cycles. In 10 females a tubal pathology was present, and in the normal female patients repeated intrauterine insemination with husband sperm had failed. The presence of an andrological factor in 17 male patients did not influence the fertilization and the cleavage of the retrieved oocytes. Although the fertilization rate of 45.8% was significantly lower than in patients with tubal pathology, the pregnancy rate was 34.2% per started cycle and 44.8% per replacement. Furthermore, the embryos were of lesser quality than in couples with tubal and idiopathic infertility. This study suggests that IVF could be considered as a useful therapeutic approach for couples with a positive direct mixed antiglobulin reaction test before advising them the use of heterologous sperm.

Adult↗
PubMed1989

The effect of pneumoperitoneum gases on fertilization, cleavage and pregnancy in human in-vitro fertilization and gamete intra-fallopian transfer.

A prospective, randomized study was carried out, creating a pneumoperitoneum with 100% CO2 or with 5% CO2 in air and evaluating the effect(s) of these gas phases on fertilization, cleavage and pregnancy outcome in this in-vitro fertilization and embryo transfer programme. There was no significant difference in the fertilization rate when either 100% CO2 or 5% CO2 in air was used for insufflation during laparoscopy. Further, embryonic development and pregnancy rates also indicated no significant differences between the two groups. Similarly, the oocytes which were retrieved and replaced with spermatozoa in the gamete intra-Fallopian transfer programme using either 100% or 5% CO2, gave similar pregnancy rates. Furthermore, the fertilization and cleavage rates of the supernumerary oocytes were not significantly different in both groups.

Carbon Dioxide↗
PubMed1989

Zygote intra-fallopian transfer as an alternative treatment for male infertility.

The results of 42 zygote intra-Fallopian transfer cycles in 37 couples with persistent male infertility are reported. Of 396 retrieved oocytes, 39.1% fertilized normally and 63 zygotes were replaced in 25 cycles. Twelve patients became pregnant, including two twin pregnancies. The pregnancy rate was 28.6% per started cycle and 48.0% per replacement. The implantation rate per replaced zygote was 22.2% (14 of 63 replaced zygotes implanted). Sixty-two supernumerary zygotes or embryos were cryopreserved for later use.

Embryo Transfer↗
PubMed1989

Time of insemination and its effect on in-vitro fertilization, cleavage and pregnancy rates in GnRH agonist/HMG-stimulated cycles.

In this prospective study, we compared the effect of delayed inseminations on fertilization, cleavage and pregnancy rates in two groups of patients. In one group, the ovarian stimulation was performed with a clomiphene citrate/human menopausal gonadotrophin/human chorionic gonadotrophin (CC/HMG/HCG) protocol. The other group was pre-treated with gonadotrophin-releasing hormone agonist (GnRHa) and ovarian stimulation was carried out with an HMG/HCG protocol. Under both protocols, a delay of 2, 4 or 6 h in insemination showed no significant differences in the fertilization, cleavage or pregnancy rates. To find out which type of oocyte has the potential for better fertilization, cleavage and implantation, a simple oocyte classification scheme is proposed. In the GnRHa/HMG group, 9% post-mature, 90% mature and only 1% immature oocytes were retrieved. The post-mature oocytes showed a tendency towards reduced fertilization when insemination was delayed. The mature and slightly immature oocytes fertilized equally well when spermatozoa were added 2, 4 or 6 h after retrieval. Similarly, no significant difference was observed in the cleavage (80%) or fragmentation (20%) rates of these oocytes. The pregnancy rates after inseminations delayed for 2, 4 and 6 h were 14, 27 and 26%, respectively. Though these figures were not statistically significant, the 4- and 6-h groups in both the IVF and zygote intra-Fallopian transfer treatments showed a slightly improved pregnancy rate compared to the 2-h group. An insemination delay of 4 h is advocated on a routine basis.

Adult↗