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Biomedical subjects

B Mason

Publications and source records attributed to B Mason.

At least 19 recordsLinked to original sources
PubMed1992

Cumulative conception and livebirth rates after in-vitro fertilisation.

Cumulative conception and livebirth rates related to age and cause of infertility provide the most useful estimate of success after in-vitro fertilisation (IVF), but limited data are available. It is also uncertain whether the probability of pregnancy, livebirth, and pregnancy failure changes with repeated treatment cycles. To assess the effects of patients' age and cause of infertility on these outcomes, we studied the results of 5055 consecutive IVF cycles (773 clinical pregnancies, 518 livebirths) undertaken on 2735 patients in a single IVF unit. Cumulative conception and livebirth rates were analysed by the life-table approach and differences in rates between age-groups and between causes of infertility were measured by the log-rank test and logistic regression modelling. Both conception and livebirth rates per cycle declined with age (p less than 0.001), and cumulative conception and livebirth rates after five treatment cycles were about 54% and 45%, respectively, at 20-34 years, compared with 38.7% and 28.9% at 35-39 years and 20.2% and 14.4% at greater than or equal to 40 years. The two rates were significantly different between causal groups (p less than 0.001 and p = 0.02, respectively) and were lowest in patients with male infertility or multiple infertility factors. The pregnancy failure rate was higher (p = 0.006) in women over the age of 34 years and there was a significant decline in the chances of pregnancy and livebirth per cycle with successive treatment cycles.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Obstetric outcome of in vitro fertilization pregnancies compared with normally conceived pregnancies.

OBJECTIVE: To compare the obstetric outcome of in vitro fertilization pregnancies with normally conceived pregnancies. STUDY DESIGN: The obstetric outcome of in vitro fertilization pregnancies achieved in 763 British residents at two in vitro fertilization clinics resulting in the births of 961 babies were compared by means of the relative risk statistic with a control group of naturally conceived primiparous pregnancies matched by maternal age and multiplicity of pregnancy. RESULTS: Twenty-five percent of in vitro fertilization pregnancies were multiple pregnancies. The incidence of singleton term breech presentation was similar to that among controls. As compared with controls there was an increased incidence among in vitro fertilization pregnancies of vaginal bleeding and hypertension requiring hospitalization (p less than 0.001) and cesarean births (p less than 0.001) and, among in vitro fertilization singleton pregnancies, an increased incidence of intrauterine growth retardation (p less than 0.05), placenta previa (p less than 0.05), and preterm delivery (p less than 0.001). The congenital malformation, stillbirth, and perinatal mortality rates were comparable with maternal age-standardized national rates. CONCLUSIONS: Although the majority of in vitro fertilization pregnancies have a satisfactory obstetric outcome, there are a number of increased obstetric risks that may reflect the history of infertility, the relatively high incidence of poor obstetric history, and the lower threshold for obstetric intervention in in vitro fertilization patients.

Adult↗
PubMed1992

The routine use of gonadotropin-releasing hormone agonists for all patients undergoing in vitro fertilization. Is there any medical advantage? A prospective randomized study.

OBJECTIVE: To determine if the routine use of gonadotropin-releasing hormone agonists (GnRH-a) for all patients undergoing in vitro fertilization (IVF) produces any significant medical advantage. DESIGN: Prospective randomized study. PATIENTS: Three hundred eight patients having their first ever IVF attempt. INTERVENTIONS: Patients were randomly divided into four groups and received either human menopausal gonadotropin (hMG) alone for ovarian simulation (group A, n = 81); clomiphene citrate and hMG (group B, n = 77); a 3-day ultrashort course of GnRH-a and hMG (group C, n = 74); or pituitary desensitization with GnRH-a followed by hMG (group D, n = 76). RESULTS: The indications for IVF and mean age of all four groups of patients were comparable. There was a significant difference in the number of embryos cleaved and transferred among the groups, but there were no significant differences in the cancellation rate, mean number of oocytes collected or fertilized, and number of cases of failed fertilization. There were also no significant differences in the pregnancy and live birth rates per cycle commenced or per embryo transfer. CONCLUSION: The routine use of GnRH-a for all patients undergoing IVF has practical but no significant medical advantages.

Abortion, Spontaneous↗
PubMed1991

Immunochemical analysis of a recombinant, genetically engineered, secreted HLA-A2/Q10b fusion protein.

We engineered a fusion gene which encodes the alpha 1 and alpha 2 domains of HLA-A2 with the alpha 3 and truncated transmembrane domains of the murine class I-like protein Q10b, and transferred it into mouse L cells along with the gene for human beta 2-microglobulin (beta 2m). The secreted rA2/Q10b gene product consisted of a single heavy chain of molecular weight 42 kd that was noncovalently associated with the human beta 2m light chain. Native detergent-solubilized HLA-A2 and secreted rA2/Q10b proteins were found to be similar by: (a) the binding to mouse monoclonal anti-HLA antibodies in an ELISA; (b) the blocking of lysis of HLA-A2+ cells by human anti-HLA-A2,-B17, anti-HLA-A2,9,28, and anti-HLA-A2,28 cross-reactive group (CREG) antisera in a complement-dependent cytotoxicity assay; and (c) the ability when coupled to Sepharose to selectively purify HLA-A2,9,28 and HLA-A2,28 CREG-specific antibodies. Mouse L cells expressing rA2/Q10b produced as much as 2.5 micrograms protein per 10(6) cells/day, or 50- to 100-fold more antigen on a per cell basis than the level of HLA-A2 expressed by B-lymphoblastoid cell line or spleen cells. Thus rA2/Q10b represents a viable alternative to detergent-solubilized HLA-A2 for purification of anti-HLA-A2 antibodies and analysis of anti-HLA-A2 immune responses.

Animals↗
PubMed1991

An investigation of the safety of the blood reinfusion step used with tunneled venous access devices in children with cancer.

Infection has been identified as the most serious potential complication of the indwelling catheter. As a result, the primary nursing goal using the catheters is to prevent infection. Nurses must frequently manipulate the catheters when securing blood specimens and are concerned that this manipulation may serve as a source of infection for the immunocompromised pediatric oncology patient. One particular step in catheter manipulation during blood sampling is blood reinfusion, ie, residual blood in the catheter is withdrawn and set aside while a second sample is collected for laboratory analysis but is subsequently returned to the patient through the catheter. The purpose of this study was to examine this nursing procedure for its potential of contaminating the blood sample that was to be reinfused, or for the potential of reinfusing a sample that contained preexisting pathogens independent of the procedure itself. An experimental design was used with 21 patients randomly assigned to an experimental group (unclean procedure to exaggerate the potential to incur pathogens during the process), and 21 randomly assigned to a control group (usual clean procedure followed with the reinfusion sample). The usual blood sampling procedure was altered for all participants as the typical amount of blood that normally constitutes the reinsertion sample was not reinserted, but was instead used to complete certain microbial analyses. Of the 42 participants, 17 were male and 25 were female; 35 were white and seven were black; 22 were diagnosed with leukemias and 20 with solid tumors. The age range for participants was 2 to 20 years (mean = 9.4 years, SD = 4.8).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Hygienic hand disinfection tests in three laboratories.

A comparative study was made in three laboratories of a test for hygienic hand disinfection. Staphylococcus aureus was applied to the fingertips of a total of 74 volunteers (49 female and 25 male) and the effect of washing with three chlorhexidine preparations and one non-medicated soap was assessed after one and five applications. Fingertip inoculation is convenient and is a realistic representation of the in-use situation. Although significant differences were obtained between log10 reductions in test organisms using the same formulation in different centres, and different periods in the same centre, the maximum differences after a single application of a preparation were small, e.g. between centres 0.39 and between periods in the same centre 0.55, and after multiple applications the maximum difference between centres was 0.42 and between periods in the same centre it was 0.51. The differences between preparations were similar in all centres. This test compares well with other similar tests and products can be placed in rank order of effectiveness. It is concluded that this test, if carried out under the controlled conditions described, is sufficiently reproducible between laboratories and repeatable within laboratories to be used as a standard test.

Chlorhexidine↗
PubMed1990

Influence of superovulation on endometrial and embryonic development.

The authors have studied the temporal relationship between follicular rupture and endometrial development in 13 women during a natural ovarian cycle (length 25 to 35 days), and subsequently after standard treatment with clomiphene citrate, human menopausal gonadotropin and human chorionic gonadotropin (hCG) to induce multiple folliculogenesis for oocyte recovery, in vitro fertilization, and embryo freezing (cycle length 23 to 27 days). An endometrial biopsy was taken during both cycles 1.5 to 2.0 days after the oocytes had been released or removed. The samples were examined by light and transmission electron microscopy. Samples of peripheral blood were taken at defined times for hormone analysis. After treatment 11 subjects (85%) had advanced morphological development of the endometrium (8 women by 3 to 4 days, 3 women by 1 to 2 days). The concentrations of plasma estradiol (E2) and progesterone (P) on the days of follicular rupture and endometrial biopsy were significantly raised in the treatment cycles. The concentration of total urinary estrogens on the day of hCG administration and the mean change in the concentration of plasma E2 (treatment/control) on the days of endometrial biopsy were positively correlated with the extent of endometrial advancement. In addition, the mean change in the concentration of plasma P (treatment/control) was markedly increased on the days of follicular rupture and endometrial biopsy in those subjects with an advanced endometrium. Embryonic development was not so obviously related to the extent of superovulation. Asynchronous endometrial and embryonic development may therefore contribute to the low pregnancy rate in these patients.

Adult↗
PubMed1990

Dose-intense weekly cyclophosphamide, methotrexate, 5-fluorouracil, vincristine and prednisolone (CMFP) in advanced breast cancer.

Weekly chemotherapy with cyclophosphamide 80 mg m-2 day-1 p.o. continuously, methotrexate 35 mg m-2 week-1 i.v., 5-fluorouracil 500 mg m-2 week-1 i.v., vincristine 1.4 mg m-2 i.v. every two weeks and prednisolone 20 mg m-2 day-1 p.o. continuously (CMFVP) was prospectively studied in 45 previously untreated outpatients with advanced breast cancer to determine the feasibility of delivering a dose-intense regimen. Of 40 evaluable patients, complete response (CR) occurred in one patient, partial response (PR) in 20 (CR + PR 53%), stable in eight, progression in 11 and five were unevaluable for response. The median relapse-free survival for responders was 25 weeks and median survival for all patients was 31 weeks. The mean dose intensity relative to the Cooper regimen fell from 1.02 to 0.6 within the first 4 weeks of treatment and the median dose intensity achieved for all patients on study was only 0.52. Eighty-seven per cent of patients had treatment delays with a mean of 3.9 delays per patient and 71% had dose reductions. Neutropenia was the major toxicity with WHO grade 3 or 4 neutropenia (less than 1.0 x 10(9) l-1) in 62% of patients and three septic deaths while neutropenic. Dose-intense weekly CMFVP in this schedule cannot be delivered to previously untreated outpatients with advanced breast cancer.

Adult↗
PubMed1990

Rare ectopic pregnancies after in-vitro fertilization: one unilateral twin and four bilateral tubal pregnancies.

Between 1985 and 1989, one unilateral twin and four bilateral tubal pregnancies were encountered among 124 extrauterine pregnancies and 1648 intrauterine pregnancies following in-vitro fertilization and embryo transfer. The two factors associated with this high incidence of single and multiple extrauterine pregnancies were tubal damage and multiple embryo transfer. Embryos at different stages of development appear to have the capacity to implant ectopically. Despite advances in diagnostic capabilities, ectopic pregnancy remains a major cause of maternal mortality. Early diagnosis prior to rupture must be made if mortality and morbidity are to be abolished. The use of transvaginal sonography has improved the diagnosis of ectopic pregnancy and should be routinely used in all pregnancies following assisted conception. The identification of an intrauterine pregnancy should not be sufficient to rule out the possibility of an extrauterine pregnancy or even bilateral tubal pregnancies.

Adult↗
PubMed1989

Studies on folliculogenesis and in vitro fertilization outcome after the administration of follicle-stimulating hormone at different times during the menstrual cycle.

The authors have undertaken a prospective, randomized clinical trial of six treatments to optimize folliculogenesis in patients prior to oocyte collection, in vitro fertilization, and embryo transfer. All treatments involved the administration of the same daily dose of follicle-stimulating hormone (FSH), but at different times during the antecedent and/or current menstrual cycle. There was a significant difference (P less than 0.01, chi-square test) between treatments in the clinical pregnancy rate/patient (19 clinical pregnancies, 67 patients). No advantages were observed for regimens that involved starting treatment during the antecedent cycle. The study was continued with the three treatments that started during the current cycle (24 clinical pregnancies, 58 patients). The most cost-effective regimen was clomiphene citrate, 100 mg/day for days 2 to 6 inclusive; FSH, 150 units/day for days 1 to 4 inclusive; and human menopausal gonadotropin, 150 units/day from day 5 until the day of human chorionic gonadotropin administration.

Adult↗
PubMed1989

Risk factors for sensitization by blood transfusions. Comparison of the UW/Madison and UC/San Francisco donor-specific transfusion experience.

We have tested the predictive model for risk of sensitization by donor-specific transfusions developed at the University of California, San Francisco for its applicability to the DST experience at UW/Madison. Patient sample sizes between the two groups were similar (n = 249 for UW/Madison, n = 261 for UCSF) and the two groups of patients had similar compositions in terms of mean age, ABO type, baseline panel-reactive antibody, and pregnancy rate. The two groups differed in that the UW/Madison group had a higher percentage of males, diabetic patients, previously transplanted patients, and 0 haplotype-matched (2 HLA-mismatched related and unrelated) recipients. In addition, all the UW/Madison patients received azathioprine (AZA) whereas only half the UCSF group was given AZA. Despite these differences, application of the UCSF model for prediction of sensitization by DST gave remarkably similar results in our patient population, with pregnancy, prior transplant, baseline PRA, and HLA antigen sharing giving similar odds ratios and P values. However, when female sex was included in the model along with the other variables, the significance of pregnancy risk disappeared. We have developed an alternative multivariate model using stepwise logistic regression that identifies baseline PRA greater than 40%, female sex, and prior transplant as significant risk factors for sensitization, while number of HLA (A, B, DR) antigens shared and increasing recipient age significantly decreased risk of sensitization by DST.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1989

Cadaveric renal transplantation with quadruple immunosuppression in patients with a positive antiglobulin crossmatch.

The significance of the antiglobulin crossmatch in the cyclosporine era remains controversial. Over an 11-month period, 124 recipients of cadaveric renal allografts (109 primary, 15 nonprimary) were retrospectively crossmatched via the antiglobulin technique. Criteria for recipient selection for transplantation included a negative T lymphocytotoxic (CDC) crossmatch for current and historical sera. Fourteen patients (11.3%) underwent transplantation in the setting of a negative T and positive antiglobulin crossmatch. The patient group included 10 female and 4 male patients with a mean age of 43.8 years. All but one patient received a primary transplant, and current sera were positive in the antiglobulin crossmatch in all cases. The mean HLA-ABDR match was 1.4 (range 0-4). Preoperative PRA titers ranged from 0 to 80% (mean 18.3%). All patients underwent successful renal transplantation with quadruple immunosuppression consisting of prednisone, azathioprine, and the sequential use of MALG/cyclosporine. There were no episodes of hyperacute rejection. However, 10 patients (71.4%) experienced acute rejection, including 7 episodes within 4 days of transplant. Early rejection was significantly more common in patients with a positive antiglobulin test (50% vs. 20.9%, P less than 0.05). The mean one-month serum creatinine was 1.7 mg/dl. Actual patient and allograft survival are 92.9% and 85.7%, respectively. Risk factors for a positive antiglobulin crossmatch included female sex and prior sensitization as measured by PRA. Although these patients represent a high-risk group for early rejection, no adverse effect on patient or graft survival was noted with quadruple immunotherapy. In conclusion, a positive antiglobulin crossmatch is no longer a contraindication to renal transplantation with current immunosuppressive strategies.

Adolescent↗
PubMed1989

Predicting survival in bilateral breast carcinoma.

Survival in 38 patients with bilateral breast cancer has been studied. The tumours were synchronous in 14 patients and metachronous in 24. Survival was less than that predicted for either tumour on the basis of a previously developed index involving lymph node status, oestrogen receptor content, progesterone receptor content, and patient age. Simple addition of the indices for the two tumours gave better predictor although this also overstated the prospects for survival for both synchronous and metachronous tumours. This experience suggests, therefore, that the prospects for survival for patients with suggests, therefore, that the prospects of survival for patients with synchronous or metachronous bilateral breast carcinoma is poor, and worse than might reasonably be anticipated.

Breast Neoplasms↗