Search PubMed⌕ Search

Biomedical subjects

B A Stone

Publications and source records attributed to B A Stone.

At least 55 records · Page 3Linked to original sources
PubMed1989

Tailoring a commercial radioimmunoassay to the range of levels of progesterone occurring in human serum during controlled ovarian hyperstimulation and following embryo/gamete transfer.

While the Pantex direct P radioimmunoassay is used widely in programs of assisted conception, its sensitivity and range do not encompass the wide range of levels of P in serum of many patients during COH and through the first trimester of pregnancy. The present communication details minor modifications to the proprietary Pantex assay which accommodate these requirements. The nature of the changes does not compromise the performance characteristics or simplicity of the original assay and facilitates precise, accurate, and rapid measurement of serum P between 0.05 and 1280 ng/ml.

Embryo Transfer↗
PubMed1989

Spontaneously resorbing ectopic pregnancy: preservation of human chorionic gonadotropin bioactivity despite declining steroid hormone levels.

We compared serum hormone profiles of patients with normal intrauterine pregnancies (n = 14), spontaneously resorbing ectopic pregnancies (n = 10), and viable ectopic pregnancies (n = 26). Hormone profiles were evaluated at 5 to 8 weeks' gestational age. Ectopic pregnancies were diagnosed by laparoscopy; intrauterine gestations were confirmed by ultrasonography. Immunoreactive beta-human chorionic gonadotropin, progesterone, estradiol, and 17-hydroxyprogesterone were measured by radioimmunoassay. Bioactive human chorionic gonadotropin was measured by a modified mouse Leydig cell bioassay. Diminished steroid production was noted in ectopic pregnancies; levels in serum of patients with resorbing ectopic pregnancies were lower than values expressed in viable ectopic pregnancies (p less than 0.01). Serum levels of human chorionic gonadotropin bioactivity correlated closely with immunoreactive human chorionic gonadotropin in all three groups (r = 0.81, p less than 0.01). Ratios of bioactive human chorionic gonadotropin to immunoreactive beta-human chorionic gonadotropin were similar (0.93 +/- 0.26 in resorbing ectopic pregnancies, 1.11 +/- 0.16 in viable ectopic pregnancies, and 0.90 +/- 0.10 in intrauterine pregnancies). We conclude that although reduced serum levels of steroids noted in ectopic pregnancy suggest an impairment in corpus luteum activity, diminished steroid production was not attributable to lower human chorionic gonadotropin bioactivity.

17-alpha-Hydroxyprogesterone↗
PubMed1989

Uterine presensitization and embryo survival and growth in Booroola Merino x South Australian Merino ewes.

The fertility enhancing effects of semen were examined following the intra-uterine insemination of killed spermatozoa plus seminal plasma 17 d prior to insemination with viable spermatozoa. Three experiments were conducted: two on 1.5-yr old and 2.5 to 5.5 yr-old Booroola Merino x South Australian Merino ewes in 1986 and one on 1.5 yr-old ewes in 1987. Differences between treatment and control groups for the percentage of ewes exhibiting estrus by Days 21 and 35 following fertile insemination, the percentage of ewes with viable embryos at Day 35, the number and weight of viable embryos per ewe, the nubmer of caruncular implantation sites and the progesterone level were not statistically significant (P>0.05). There were no statistically significant treatment by experiment interactions for any of the variables examined. Inflammation and edema of the endometrial tissue was not observed following the presensitization treatment.

Journal Article↗
PubMed1989

Responses of patients to different lots of human menopausal gonadotropins during controlled ovarian hyperstimulation.

Responses of patients treated with different lots of human menopausal gonadotropin (hMG) during controlled ovarian hyperstimulation were analyzed. Levels of luteinizing hormone (LH) in serum varied between groups of patients treated with different hMG lots, serum follicle-stimulating hormone (FSH) levels did not differ. In the analysis of levels of estradiol (E2) in serum of patients pretreated with leuprolide acetate (gonadotropin-releasing hormone analog; GnRH-a), there was an interaction between hMG lot and day of stimulation. E2 levels/follicle also diverged between hMG batches as ovum pick-up approached. Within the groups of patients pretreated with GnRH-a, serum FSH/LH ratios varied between 5 and 20, with a batch x day interaction. Ongoing pregnancy rates in the hMG-treatment groups ranged between 0/24 and 7/33 (21%).

Estradiol↗
PubMed1989

Gonadotropin and estradiol levels during ovarian stimulation in women treated with leuprolide acetate.

Levels of FSH, LH, and estradiol (E2) were measured in the serum of 209 gonadotropin-releasing hormone analogue-treated women and in 202 control subjects during the final 5 days of ovarian stimulation in our in vitro fertilization program. Levels of FSH and E2 in serum of gonadotropin-releasing hormone analogue-treated subjects significantly exceeded control values during the sampling period, whereas LH levels were significantly lower. Concentrations of E2 in serum of gonadotropin-releasing hormone analogue-treated and control subjects were similar when corrected for differences in numbers of follicles aspirated at oocyte retrieval (mean of 8.9 and 7.2 follicles per subject, respectively). Pregnancy rates by diagnostic ultrasound were 18 and 11%, respectively, a statistically significant difference.

Estradiol↗
PubMed1989

Levels of interleukin-2 receptor in serum of patients during the menstrual cycle and following embryo/gamete transfer.

In an attempt to establish whether nidation elicits a measureable systemic immunologic response in vivo, levels of interleukin-2 receptor (IL-2R) have been determined in serum drawn from 34 pregnant patients (IUP) immediately before embryo/gamete transfer, and 7 and 14 days later. For comparison, these same values were determined for 41 subjects who did not conceive, and for 18 who spontaneously aborted (SAB) during the first trimester of gestation. Serum IL-2R values were near 320 U/ml and did not differ between days within outcomes, or within days between outcomes. Furthermore, levels of IL-2R and beta-hCG in serum were not interrelated on days 7 or 14 of pregnancy (SAB or IUP). Serum IL-2R levels did not change during the menstrual cycle. The present results appear to traverse presumptive elements of existing hypotheses of "placental immunotropism."

Chorionic Gonadotropin↗
PubMed1988

Luteotropic activity in serum of women following embryo or gamete transfer in a program of assisted conception.

In an attempt to track the proliferation/demise of trophoblastic tissues in women following gamete transfer (GT) or in vitro fertilization/embryo transfer (IVF/ET), we have measured levels of human chorionic gonadotropin (hCG) in serum of 180 patients on days 7 and 14 following oocyte pickup (OPU). Serum hCG levels were measured by immunoassay and by a bioassay based on the capacity of the sample to stimulate testosterone secretion by cultured mouse Leydig cells. Based on determinations of bioactive and immunoactive hCG in serum from 18 of 180 patients who subsequently delivered (12 of 73 GT, 6 of 107 IVF/ET; P less than 0.05) and classification of patients in accord with their compliance or noncompliance with these ranges of values, about 70% of all patients in the present study were classified as "pregnant" 7 days following OPU. Based on these same criteria, about 23% were pregnant 7 days later. Biochemical pregnancy rates on days 7 and 14 following GT (near 73 and 27%, respectively) were not different from the respective values following IVF/ET (near 68 and 20%, respectively; P greater than 0.05). The luteotropin bioassay described is highly sensitive to hCG (to 0.02 mIU/ml serum) and appears appropriate to the characterization of proliferation/demise of embryonic tissues during the 14 days after gamete/embryo transfer. In addition, through its representation of the cumulative luteotropic properties of human serum and its insensitivity to biologically inactive hCG subunits, this bioassay appears more appropriate than hCG immunoassay in the monitoring of early embryonic signalling following assisted (or spontaneous) conception in the woman.

Chorionic Gonadotropin↗
PubMed1988

Levels of steroid and protein hormones in antral fluids of women treated with different combinations of gonadotropins, clomiphene citrate, and a gonadotropin-releasing hormone analog.

Levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol, progesterone (P), and total protein in follicular fluids collected from 18 patients pretreated with a gonadotropin-releasing hormone analog (GnRHa), in association with human menopausal gonadotropin (hMG) and FSH, were compared with values for 69 patients treated with FSH, hMG, FSH/hMG, or clomiphene citrate (CC)/hMG in an in vitro fertilization (IVF) program. The authors have established a number of significant differences in chemical and physical properties of follicular fluids of patients treated by different regimen, and concur with earlier evidence that the volume of a follicle, and its P and total protein content, are related to the maturity of the oocyte nested within the follicle. Overall, however, differences in concentrations of gonadotropins in follicular fluids between groups were not consistent with differences in follicular fluid steroid levels, and levels of immunoactive gonadotropins in follicular fluids were not in accord with dosages of exogenous immunoactive gonadotropin administered during hyperstimulation. The most favorable outcomes of IVF (greater than 70% of oocytes fertilized) were established with oocytes collected from patients treated with FSH only or with CC/hMG, and patients treated with FSH only yielded the highest average number of oocytes which fertilized in vitro (6.2 per patient).

Body Fluids↗
PubMed1988

Interrelationships between plasma hormone levels and the content of total protein, gonadotropins and steroid hormones in antral fluids of women undergoing in vitro fertilization.

Follicle development was induced in 41 women with follicle-stimulating hormone (FSH) and human menopausal gonadotropin. Blood samples were drawn and follicular fluids (FF) were aspirated when two or more follicles attained diameters of 15 to 17 mm. Levels of estradiol (E2), progesterone (P), FSH, and luteinizing hormone (LH) were determined in samples by radioimmunoassay, and relationships between the measured parameters in antral fluids and in serum were examined by least-squares linear regression analysis. Levels of LH in serum correlated with LH and FSH levels in FF (P less than 0.005). Concentrations of FSH in serum were positively related to levels of LH, FSH, E2, and total protein in FF (P less than 0.005). E2 levels in serum were predictive of E2 levels in FF only, and levels of P in serum were directly correlated with P levels in FF (P less than 0.05). With respect to the peculiarly broad range of predictions that could be drawn from the FSH content of serum, peripheral FSH provided a better predictive index of the chemical composition of antral fluid than did the level of any other single hormone measured in serum.

Female↗
PubMed1988

Methods used to improve gamete efficiency.

Male factor infertility accounts for a significant percentage of problems in infertile couples. With clinical utilization of the technologies for selection of good-quality spermatozoa from the ejaculate, our ability to successfully treat the severely affected male factor couple has improved. However, it must be remembered that even with current technologies, fertilization success is reduced in these patients but remains above a 50% level. Other factors that can be used in the future to improve on these statistics are being investigated in regard to the in vitro environment for gametes, that is, the type of culture medium, the methods of coincubation of the sperm and egg, and other methods of enhancement of sperm fertilizing potential. However, methods of sperm preparation will achieve improvement in a percentage of these males treated, and can be used to improve fertilization and pregnancy success. It is important to understand the limitations of the zona-free hamster test, but it is also important to use that test as a screening method for sperm handling. By utilizing the SPA to select out the optimal method of sperm preparation, the fertilization and pregnancy outcome can be improved. Overall, the live-birth rate in male factor infertile couples is lower than non-male-factor couples treated by IVF and GIFT. Until more is known about basic spermatozoal function, and the ability to improve that function in affected males, the live-birth rate should not be expected to change substantially.

Cell Separation↗
PubMed1988

Introduction of a porcine growth hormone fusion gene into transgenic pigs promotes growth.

Six transgenic pigs have been produced by microinjecting a human metallothionein promoter/porcine growth hormone gene construct into the pronuclei of fertilized eggs which were transferred to synchronized recipient sows. The resulting transgenic animals contained between 0.5 and 15 copies of the gene construct per cell, and at least one of the animals expressed the introduced gene and grew at an increased rate compared to both transgenic and non-transgenic littermates. Some of the transgenic animals that did not appear to grow at increased rates were found to contain rearranged gene sequences. Two of the transgenic pigs have been shown to pass on the introduced genes to their offspring.

Animals↗
PubMed1987

Tumor-specific genetically engineered murine/human chimeric monoclonal antibody.

Murine variable and human constant region exons were fused to produce "chimeric" immunoglobulin gamma and kappa genes. These constructs were cotransfected into murine myeloma cells which then produced and secreted intact, functional antibody. Cells secreting the chimeric antibody were introduced into mice. The engineered immunoglobulin was subsequently harvested from ascites fluid and was purified by affinity chromatography. Its immunological properties were compared to those of the parental murine monoclonal (B6.2), which exhibits specificity for human breast, lung, and colon carcinoma cells. Competitive binding, immunofluorescent cell staining, and analysis of immunoprecipitated antigen gave similar results for the chimeric and murine B6.2. The biodistribution of chimeric and murine B6.2 after injection into mice bearing human tumors was found to be identical. These results suggest that murine/human chimeric antibodies may be viable clinical replacements for murine monoclonals with the potential for better immunological tolerance and pharmacological efficacy.

Animals↗
PubMed1987

Comparative effects of dietary wheat bran and its morphological components (aleurone and pericarp-seed coat) on volatile fatty acid concentrations in the rat.

Adult male rats were fed on diets containing 100 g dietary fibre/kg either as alpha-cellulose or wheat bran or the pericarp-seed coat or aleurone layers prepared from that bran by sequential milling and air elutriation and electrostatic separation. After 10 d, concentrations of total volatile fatty acids (VFA) in caecal fluid were significantly different between groups and fell in the order: aleurone greater than wheat bran greater than pericarp-seed coat greater than cellulose. This ranking probably reflected the ease of fermentation of fibre polysaccharides by colonic bacteria which also resulted in a considerably higher faecal bacterial mass in the aleurone group. Because of the differences in the volume of caecal digesta, the mass of caecal VFA was considerably the highest in the aleurone group, intermediate with wheat bran and equally low in the pericarp-seed coat and cellulose groups. The diet based on aleurone gave a relatively higher proportion of propionate but with both pericarp-seed coat and wheat bran the contribution of butyrate was raised. VFA concentrations in hepatic portal venous plasma were proportional to caecal concentrations with very high (greater than 3 mM) values being recorded in the aleurone group. The findings are discussed in relation to the apparent susceptibility of the morphological components of wheat bran to fermentation by large bowel bacteria.

Animals↗
PubMed1987

Changes in peripheral progestagen levels in early pregnant gilts following injection of human chorionic gonadotrophin.

The capacity of human chorionic gonadotrophin (hCG) to raise plasma progestagen levels during the first 8 days of gestation in gilts was examined. The effective half-times of hCG in gilts treated with 500 and 5000 i.u. hCG were 29.1 and 26.3 h respectively (P greater than 0.05). Neither 500 nor 5000 i.u. hCG caused rises in peripheral concentrations of progesterone or pregnenolone sulphate, and plasma pregnenolone concentrations declined (P less than 0.05) following hCG treatment. Apart from diminished total corpus luteal weights in gilts treated with 500 i.u. hCG (P less than 0.05) and lower peripheral progesterone levels in gilts treated with 5000 i.u. hCG (P less than 0.05), ovarian and plasma steroid characteristics of hCG-treated animals between 23 and 25 days of gestation were similar to control values. Furthermore, treatment with hCG did not affect embryo survival during the first 4 weeks of pregnancy, and plasma oestrone/oestrone sulphate levels provided no evidence for differences between control and treated animals in trophoblastic outgrowth. These results challenge the rationale for the treatment of early pregnant sows with hCG in order to reduce the levels of embryonic wastage in early pregnancy.

Animals↗
PubMed1986

A genetically engineered murine/human chimeric antibody retains specificity for human tumor-associated antigen.

Chimeric immunoglobulin genes were constructed by fusing murine variable region exons to human constant region exons. The ultimate goal was to produce an antibody capable of escaping surveillance by the human immune system while retaining the tumor specificity of a murine monoclonal. The murine variable regions were isolated from the functionally expressed kappa and gamma 1 immunoglobulin genes of the murine hybridoma cell line B6.2, the secreted monoclonal antibody of which reacts with a surface antigen from human breast, lung, and colon carcinomas. The kappa and gamma 1 chain fusion genes were co-introduced into non-antibody producing murine myeloma cells by electroporation. Transfectants that produced murine/human chimeric antibody were obtained at high frequency as indicated by immunoblots probed with an antisera specific for human immunoglobulin. Enzyme-linked immunoabsorbent assay analysis demonstrated that this chimeric antibody was secreted from the myeloma cells and retained the ability to bind selectively to membrane prepared from human tumor cells. The chimeric immunoglobulin was also shown by indirect fluorescence microscopy to bind to intact human carcinoma cells with specificity expected of B6.2. The ability of chimeric antibody to recognize human tumor-associated antigen makes feasible a novel approach to cancer immunotherapy.

Animals↗