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Biomedical subjects

B A Lieberman

Publications and source records attributed to B A Lieberman.

At least 73 records · Page 4Linked to original sources
PubMed1991

Characterization and functional properties of the A and B forms of human progesterone receptors synthesized in a baculovirus system.

Human progesterone receptors (PR) were overexpressed in Spodoptera frugiperda (Sf9) insect cells using a recombinant baculovirus system. Recombinant viruses were constructed that produced either full-length A (94K) or B (120K) forms of human PR, and each was expressed as a functional protein. Steroid and DNA binding activities were found to be indistinguishable from that of endogenous human PR in T47D breast cancer cells. Moreover, as analyzed by gel-mobility shift, recombinant PR-A and PR-B each bound to specific progesterone response elements in a strictly hormone-dependent manner. Native receptors expressed in Sf9 cells also exhibited structural properties similar to that of endogenous PR. Cytosolic PR (PR-A or PR-B), prepared in low salt buffer, sedimented on density gradients as an 8S oligomeric complex that was converted largely to 4S by treatment with 0.4 M NaCl. Immune isolation of the 8S cytosol PR complex and analysis of protein composition revealed the presence of two specific copurifying proteins of approximately 90K and 70K. The 90-K component was identified immunologically as heat shock protein 90. The 70-K component was not identified but is likely to be the insect equivalent of heat shock protein 70. Immune isolation of PR from Sf9 cells metabolically labeled with [32Pi], revealed that expressed PR was capable of being phosphorylated in insect cells. Hormone addition to Sf9 cells, however, did not stimulate the same increase in PR phosphorylation or upshift in mobility on sodium dodecyl sulfate gels that occurs with endogenous receptors in T47D cells. Thus some, but not all, phosphorylations occur with human PR expressed in Sf9 cells. These phosphorylation data, together with the fact that expressed PR required hormone for DNA binding, indicate that the hormone-dependent phosphorylation step responsible for PR upshifts on sodium dodecyl sulfate-polyacrylamide gel electrophoresis is not required for receptor binding to DNA. The baculovirus expression system, therefore, may prove valuable in dissecting the functional role(s) for both hormone-dependent and hormone-independent PR phosphorylation.

Animals↗
PubMed1990

Measurement of human chorionic gonadotropin during early pregnancy: a comparison of two immunoradiometric assays.

Evidence of implantation following either in vitro fertilization and embryo transfer (IVF-ET) or gamete intrafallopian transfer (GIFT) was obtained by collecting blood on days 10, 12, 14, 16, and 18 after oocyte recovery (day 0), and retrospectively measuring human chorionic gonadotropin (hCG). This was done using immunoradiometric assays for hCG, manufactured either by Serono Diagnostics Ltd. (MAIAclone) or Diagnostics Products Corporation (IRMA-count). The analysis of 63 serum samples by both kits showed a good correlation (r = 0.99) but the Serono (y) method gave values which were consistently greater (y = 1.58x + 4.89) than those of the DPC (x) method. A comparison of the hCG profile of singleton pregnancies measured with either the Serono (n = 33) or DPC (n = 22) kits gave a similar relationship. These results suggest that great care must be taken when comparing results from different laboratories using different kits. Also, consideration must be given to the possible loss of a continuous database should a laboratory change kit.

Chorionic Gonadotropin↗
PubMed1990

Serum PP14 levels in a patient with Turner's syndrome pregnant after frozen embryo transfer.

Data are presented on serum levels of the pregnancy-associated placental protein (PP14) in an XO mother, pregnant after frozen embryo transfer. Steroid replacement before and during early pregnancy was provided with transdermal oestradiol and vaginal micronized progesterone. Characterization of a pre-treatment cycle indicated a physiological response by the endometrium. The pregnancy was associated with normal maternal blood levels of all hormones considered responsible for maintenance of early gestation but with consistently subnormal serum levels of PP14. Hitherto, PP14 has been believed to be an endometrial protein arising from the decidua during pregnancy, under the influence of ovarian steroids. The findings in this case suggest that other factors are involved in its production, possibly under the control of, or originating from, the maternal ovary.

Adult↗
PubMed1990

Use of buserelin in an IVF programme for pituitary-ovarian suppression prior to ovarian stimulation with exogenous gonadotrophins.

Daily s.c. injections of buserelin were commenced in the mid-luteal phase of the preceding cycle in 118 women undergoing in-vitro fertilization (IVF) and embryo transfer. Ovarian and pituitary suppression was said to have been adequately achieved when serum oestradiol was less than 50 pg/ml, serum LH less than 2.0 IU/l, no ovarian cysts greater than or equal to 10 mm diameter were present and menstruation had occurred. Nine groups of women were retrospectively identified after the administration of buserelin for 12 days according to whether pituitary and ovarian suppression had been achieved or not, and the reason for extended buserelin treatment prior to ovarian stimulation. Upon adequate suppression, patients were grouped in terms of the duration of exposure to buserelin, and ovarian stimulation was then started by daily injections of human menopausal gonadotrophin. There appeared to be no differences in the ovarian response for women down-regulated by day 12, 19 or greater than or equal to 26 days; those women requiring extended buserelin treatment did equally well compared to those women down-regulating quickly, in terms of number of oocytes recovered and fertilization rate. Clinical pregnancy rates per embryo transfer were 27/68(40%), 8/33(26%) and 4/17(24%) for those women down-regulated by days 12, 19 or greater than or equal to 26 respectively, and were not significantly different.

Adult↗
PubMed1990

Endocrine changes in women conceiving during treatment with an LHRH agonist.

We report on eight patients who conceived during pituitary desensitization with buserelin in the luteal phase of the menstrual cycle. Pregnancy was diagnosed between day 12 and 21 of buserelin administration. Analysis of serum luteinizing hormone on day 12 showed that pituitary desensitization occurred in conjunction with increasing production of ovarian steroid hormones. Serum concentrations of human chorionic gonadotrophin (HCG) were less than 10 IU/l on day 1 of buserelin administration for seven of the eight patients. The serum concentration of HCG on day 12 showed a median value of 722 IU/l (range 14.6-798 IU/l). Five of the eight patients were given HCG support (10,000 IU) following the diagnosis of pregnancy--three of these patients have ongoing pregnancies and the remaining two had blighted ova on scan. Of the remaining three patients, one had a singleton pregnancy which miscarried at 9 weeks, one had a blighted ovum on scan and bled per vagina shortly after this, and one bled per vagina prior to a scan being carried out. Our results show that pregnancy can occur during pituitary desensitization with buserelin, despite patients being counselled not to have unprotected intercourse in the cycle during which administration commences. An HCG assay on day 1 of buserelin administration is not helpful. Pregnancy should be suspected when ovarian steroid production persists despite complete pituitary down-regulation.

Adult↗
PubMed1990

Fertilization in vitro of supernumerary oocytes following gamete intra-fallopian transfer (GIFT).

Gamete intra-Fallopian transfer (GIFT) was performed in 130 treatment cycles over a 17-month period. In 91% (118/130) of the cycles one or more oocytes were available for insemination in vitro and only GIFT cycles with supernumerary oocytes were included in the present study. Pituitary and ovarian suppression was achieved with buserelin followed by stimulation of multifollicular development by human menopausal gonadotrophin (HMG). Failure of supernumerary oocytes to fertilize was associated with a significantly reduced pregnancy rate (3/23; 13%) compared to cycles where fertilization occurred in vitro (35/95; 37%). These findings demonstrate that the outcome of IVF of supernumerary oocytes may be of particular diagnostic value in couples where the female partner has not conceived following treatment by GIFT after pituitary down-regulation with buserelin and ovarian stimulation with HMG.

Adult↗
PubMed1990

The cryopreservation of donor semen by a simplified method: use in an IVF and GIFT programme.

The cryopreservation of semen used in assisted reproduction procedures was carried out exclusively by a simplified method in which a mixture of semen and cryoprotectant was contained in 1-ml tuberculin syringes and plunged directly into liquid nitrogen. Donor semen samples halved and frozen in syringes and in straws in a controlled-rate freezer showed no significant difference in post-thaw motility (P = 0.217) or survival (P = 0.217) after 30 min. However, after 180 min the survival rate showed a significant reduction in syringes (P = 0.045). A significant difference (P less than 0.00008) in the rate of fertilization of oocytes was seen in IVF cycles using frozen-thawed donor sperm (58/142, 42%) when compared to fresh sperm from husbands (2315/3926, 59%). A significant reduction (P less than 0.00005) in fertilization rate was also observed in the case of supernumerary oocytes in GIFT cycles with the cryopreserved donor sperm (29/132, 22%) compared to the husbands' sperm (239/514, 46%). However, the pregnancy rate following IVF and embryo replacement was the same after fertilization with fresh sperm (75/351, 21%) as opposed to frozen sperm (3/14, 21%). Furthermore, a higher pregnancy rate was observed in GIFT with frozen donor sperm (9/19, 47%) than with fresh sperm from husbands (28/103, 27%), though this was not statistically significant (P = 0.079). These results show this simplified methods of semen cryopreservation to be effective when used in an IVF and GIFT programme, giving pregnancy rates comparable to fresh normospermic semen samples. The method is simple, quick and inexpensive.

Cell Survival↗
PubMed1989

Quality control in an in-vitro fertilization laboratory: use of human sperm survival studies.

A bioassay procedure is described for quality control testing of various disposable items used in routine IVF procedures. This bioassay is performed over 4 days and uses the survival of human sperm in vitro at room temperature to assess which products are suitable for use. New products were tested for cytotoxicity using a general screening method and subsequent batches of every suitable item tested to detect interbatch variation. Products were considered suitable or unsuitable for use depending upon a calculated sperm survival index. Two main types of product were found to be cytotoxic, namely certain brands of syringe and surgical gloves, the common feature of both being the presence of rubber components. The bioassay was also used to investigate further the cytotoxic effect of the powdered and starch-free surgical gloves. The cytotoxic substances from both types of surgical glove were readily transferred to an embryo replacement catheter by touch, and washing of the gloves reduced this effect only moderately. The bioassay has proved inexpensive and convenient but more importantly it has been invaluable for detecting potential sources of cytotoxicity before they are introduced into a standard IVF protocol.

Cell Survival↗
PubMed1989

Fertilization of human oocytes in vitro by spermatozoa from oligozoospermic and normospermic men.

Sperm were isolated from the semen of oligozoospermic (less than 20 x 10(6) sperm/ml) and normospermic (greater than or equal to 20 x 10(6) sperm/ml) men in an in-vitro fertilization (IVF) programme. Oocytes from the female partners were inseminated with either 75 or 100 x 10(3) motile sperm and checked for fertilization after 16-20 h. A significant reduction in the overall fertilization rate of oocytes was seen for the oligozoospermic group compared to the normospermic group, at both insemination concentrations. In the oligozoospermic group, a fertilization rate of 31% (19/61) was achieved when oocytes were inseminated with 75 x 10(3) sperm, and 38% (9/24) when inseminated with 100 x 10(3) sperm. This compared with rates of 57% (397/696) and 64% (650/1018), respectively, for normospermic cases at both insemination concentrations. No evidence of fertilization was seen in 36% (4/11) and 67% (4/6) of oligozoospermic cases when 75 or 100 x 10(3) sperm were used, compared with values of 13% (17/133) and 9% (20/212), respectively, in normospermic cases. After excluding zero cases, the fertilization rate of oocytes for the oligozoospermic group (75%; 9/12) was similar to the normospermic group (70% 650/935) when 100 x 10(3) sperm were used. However, when 75 x 10(3) sperm were used, the fertilization rate for the oligozoospermic group (41%; 19/46) was significantly lower than that of the normospermic group (62%; 397/645). Following the transfer of embryos into the female partner, clinical pregnancies were diagnosed in 2/7 (29%) oligozoospermic cases and 27/267 (10%) normospermic cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1988

Factors associated with accidental fractures of the zona pellucida and multipronuclear human oocytes following in-vitro fertilization.

A total of 101 multipronuclear oocytes (7.4% of fertilizations) were retrospectively identified in this in-vitro fertilization programme. The use of a manual syringe suction system, instead of an electric pump, to aspirate follicles, was associated with a significant increase in the proportion of oocytes with fractured zonae pellucidae (P less than 0.001), a lower normal fertilization rate (P less than 0.05) and a higher proportion of multipronuclear fertilizations (P less than 0.001). Irrespective of the mode of follicular aspiration, significantly more multipronuclear fertilizations occurred following stimulation with a combination of clomiphene and human menopausal gonadotrophin, than after clomiphene alone (P less than 0.05). It was concluded that the aspiration pressures, created by syringe suction, were more likely to rupture the zona pellucida of some oocytes, while in others it predisposed to an increased multipronuclear fertilization rate.

Female↗
PubMed1984

Impact of improved perinatal care on the causes of death.

A total of 440 perinatal deaths occurring in a maternity hospital over a 6 year period have been analysed clinically and pathologically. The decline in mortality could be attributed to a reduction in asphyxial deaths, lethal malformations, and macerated stillbirths. The establishment of a neonatal intensive care unit seemed to have been more successful in combating birth asphyxia than respiratory distress syndrome. Although the greatest reduction in perinatal mortality was in babies with birthweights between 1 and 1.5 kg, there was no decline in the deaths from hyaline membrane disease or intraventricular haemorrhage, or both. The most striking change was the drop in asphyxia as a cause of perinatal death which was independent of birth trauma. Earlier diagnosis of fetal distress with obstetric intervention and the establishment of the intensive care unit were seen as the main factors in this change, and their mutual dependence and evolution are emphasised.

Asphyxia Neonatorum↗