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Biomedical subjects

M C Bowman

Publications and source records attributed to M C Bowman.

At least 19 recordsLinked to original sources
PubMed1999

Role of primary constitutive phosphorylation of Sendai virus P and V proteins in viral replication and pathogenesis.

Functional analysis of the primary constitutive phosphorylation of Sendai virus P and V proteins was performed using both in vitro and in vivo systems. Sendai virus minigenome transcription and replication in transfected cells were not significantly affected in the presence of primary phosphorylation deficient P protein (S249A, S249D, P250A) as measured by either the luciferase activity or the Northern blot analysis. Similarly, recombinant Sendai viruses lacking the primary phosphorylation in P grew to titers close to the wild-type virus in cell cultures and in the natural host of Sendai virus, the mouse. Mutant viruses showed no altered pathogenesis in mice lungs. Oligomerization of P by binding WT P or mutant P to GST-P (WT) Sepharose beads revealed that the primary phosphorylation was not crucial for P protein oligomerization. Similar to P protein primary phosphorylation, the V protein primary phosphorylation at serine249 was not essential for minigenome transcription and replication, as both WT and mutant V proteins were found equally inhibitory to the minigenome replication. These results show that the primary phosphorylation of P protein has no essential role in Sendai virus transcription, replication, and pathogenesis.

Animals↗
PubMed1999

Dissection of individual functions of the Sendai virus phosphoprotein in transcription.

The Sendai virus P protein is an essential component of the viral RNA polymerase (P-L complex) required for RNA synthesis. To identify amino acids important for P-L binding, site-directed mutagenesis of the P gene changed 17 charged amino acids, singly or in groups, and two serines to alanine within the L binding domain from amino acids 408 to 479. Each of the 10 mutants was wild type for P-L and P-P protein interactions and for binding of the P-L complex to the nucleocapsid template, yet six showed a significant inhibition of in vitro mRNA and leader RNA synthesis. To determine if binding was instead hydrophobic in nature, five conserved hydrophobic amino acids in this region were also mutated. Each of these P mutants also retained the ability to bind to L, to itself, and to the template, but two gave a severe decrease in mRNA and leader RNA synthesis. Since all of the mutants still bound L, the data suggest that L binding occurs on a surface of P with a complex tertiary structure. Wild-type biological activity could be restored for defective polymerase complexes containing two P mutants by the addition of wild-type P protein alone, while the activity of two others could not be rescued. Gradient sedimentation analyses showed that rescue was not due to exchange of the wild-type and mutant P proteins within the P-L complex. Mutants which gave a defective RNA synthesis phenotype and could not be rescued by P establish an as-yet-unknown role for P within the polymerase complex, while the mutants which could be rescued define regions required for a P protein function independent of polymerase function.

Animals↗
PubMed1995

Inter-observer variability at laparoscopic assessment of pelvic adhesions.

A total of 25 women undergoing videolaparoscopy and a dye test to investigate pelvic adhesions and infertility were evaluated to determine whether applying a score system to pelvic adhesions was reproducible, and its place in determining prognosis or management. The surgeon performing the laparoscopies scored each case using the American Fertility Society (AFS) system, gave an estimate of the likely prognosis from microsurgery and recorded a recommended management [surgery or in-vitro fertilization (IVF)]. The video images and histories were independently reviewed by two other surgeons experienced in tubal surgery, who also scored each case and recorded prognosis from surgery and recommended management. Several differences in adhesion scores for each case were noted. Agreement was present between surgeons regarding estimated prognosis for microsurgery and also in recommending management, particularly when prognosis was considered poor and IVF was recommended. Despite some reproducibility, the AFS score system did not predict outcome or management decisions. However, the surgeons' fundamental impression of the state of the pelvis and recommendation for either surgery or IVF were more consistent and reproducible. Any future proposed system for adhesion classification will need to account for, and be predictive of, the decreasing number of patients for whom surgery (rather than IVF) is the preferred management.

Adnexal Diseases↗
PubMed1994

Community attitudes to maternal age and pregnancy after assisted reproductive technology: too old at 50 years?

Community attitudes toward oocyte and embryo donation, and toward assisted reproduction after the menopause were assessed in this survey of 1131 Australians. Of the respondents, 64.2% believed that oocyte or embryo donation was an acceptable treatment for infertile couples, 54.6% felt that it was acceptable for a woman to have her own embryos transferred after the menopause, and 37.9% are accepting of the donation of eggs or embryos to post-menopausal women. There were no significant differences in response amongst different religious groups, or in relation to gender or income level. Significantly higher levels of acceptance were noted for all categories amongst those respondents aged < 35 years. Despite the established clinical ability to achieve pregnancy in the over 50 years age group, this survey reveals only minority community support for this practice. However, public opinion may alter in the future if the attitudes of the younger proportion of the sample are maintained.

Adolescent↗
PubMed1994

Comparison of fallopian tube intraluminal pathology as assessed by salpingoscopy with pelvic adhesions.

OBJECTIVE: To correlate the severity and extent of pelvic adhesions, as noted at laparotomy for microsurgery, with the presence and extent of fallopian tube intraluminal pathology, as noted using salpingoscopy. DESIGN: Prospective clinical study. SETTING: A university teaching hospital. PATIENTS: Twenty patients presenting for pelvic microsurgery between July 1992 and January 1993. INTERVENTIONS: Salpingoscopy was performed at the time of microsurgery and intraluminal pathology was scored. An objective assessment of the extent of pelvic adhesions was made using standardized adhesion score systems. RESULTS: There was a strong correlation between the degree of intratubal damage and the extent of pelvic adhesions when the etiology was previous pelvic inflammatory disease (PID) but not when the underlying etiology was endometriosis. However, in the endometriosis subgroup, intraluminal ampullary pathology was noted in 27% of tubes assessed, and intraluminal fimbrial pathology was noted in 36% of tubes assessed. Intraluminal tubal pathology also was noted in a number of cases where the underlying etiology was previous surgery for benign disease. CONCLUSIONS: This study confirms previous reports that, in cases of PID leading to adhesions, there is a high incidence of intraluminal pathology. However, this study also demonstrates that intraluminal pathology is often associated with adhesions arising from other etiologic groups, suggesting that intraluminal assessment is required for all patients in whom adhesiolysis for fertility is considered.

Endometriosis↗
PubMed1993

Investigation of impaired ovarian function as a contributing factor to infertility in women with pelvic adhesions.

A prospective study was performed to determine whether a relationship exists between infertility as a result of pelvic adhesions, and raised follicle stimulating hormone (FSH). A total of 66 patients, who had a diagnostic laparoscopy and dye performed as part of their infertility work-up, had an early cycle serum FSH drawn one to two cycles after this procedure. Patients were divided into two groups, one with pelvic adhesions as a result of surgery, infection or endometriosis, and a control group consisting of those with a normal pelvis at laparoscopy or with minimal/mild endometriosis without adhesions. In the adhesion group, a correlation was noted between American Fertility Society (AFS) adhesion score and basal FSH concentration, although all FSH values for this group were within the normal range. This study suggests a correlation between pelvic adhesions and ovarian compromise, but a larger study involving more severe cases of adhesions is required to determine whether this finding is of clinical importance.

Basal Metabolism↗
PubMed1993

A comparison of early pregnancy failure and ongoing pregnancy rates between fresh and frozen embryo transfer following in vitro fertilization.

In order to compare pregnancy outcomes following fresh and frozen embryo transfer after in vitro fertilization (IVF), a retrospective analysis of data from the Royal North Shore IVF Programme was performed. Six hundred and sixty seven embryo transfers following routine IVF were performed during 1991 and 1992. Four hundred and twenty fresh embryo transfers were performed during that period, resulting in a clinical pregnancy rate of 21%. In comparison, 247 frozen transfers, where the initial procedure was routine IVF, were performed, resulting in a clinical pregnancy rate of 16.6%. This difference was not significant. When varying numbers of transferred embryos in the 2 groups were taken into account, there was a significant difference in the proportion of ongoing viable fetuses per embryo returned for 1991, but not for 1992. Although there were a greater number of abortions and ectopic pregnancies in the fresh transfer group, these differences did not achieve statistical significance. The implications of improving results from frozen embryo transfer are discussed.

Abortion, Spontaneous↗
PubMed1991

Vergence orthoptics: validity and persistence of the training effect.

The validity and permanence of orthoptic treatment for vergence deficiencies requires investigation due to the subjective nature of determining success in most clinical cases, i.e., the amelioration of symptoms and increases in vergence ranges. The relation between Risley prism vergences, a subjective measure, and vergence tracking rate, an objective index, is investigated. The course of orthoptics progress is compared in cases of clinical vergence dysfunction. Vergence-deficient control subjects showed no significant change in either index. However, trained subjects demonstrated rapid increases in both indices. The persistence of the training effect was monitored for up to 9 months. No regression was observed in subjects who met all release criteria, but one subject who chose to terminate therapy early showed a slow regression in tracking rate and recurrence of symptoms. These data support the validity of vergence training and increase the plausibility of previous clinical reports of orthoptics success.

Adult↗
PubMed1982

A "marker" technique to monitor treated industrial wastewater effluents.

In toxicological research with hazardous substances (e.g. carcinogens), wastewater effluent from the test facility must be free of such substances before discharge into the environment. An industrial wastewater processing employing adsorbers of carbon and XAD-2 resin is described; however, chemical assays of each batch of treated effluent must certify the absence of all test agents. Elution profiles and adsorption isotherm tests with the test agents vs. the two adsorbents provided the basis for a "marker" technique which should eliminate the necessity to assay for all test agents in each batch of processed effluent. A radionale is presented for periodic introduction of a "marker" (gentian violet) into the primary adsorbers. If detected in the effluent, the "marker", which elutes from the adsorbers before most of the test agents would signal impending depletion of the adsorbent which could then be replaced. Recommendations to modify the industrial wastewater treatment plant and to implement the "marker" technique are presented as cost-effective alternatives to extensive and laborious chemical assays.

Carcinogens↗
PubMed1982

A rapid procedure to efficiently clean blenders repeatedly used to prepare dosed feed for bioassays.

An effective and economical procedure is described to clean blending equipment repeatedly used to prepare dosed feed for animal bioassays. The cleanup procedure was evaluated with 2 types of blenders against 10 test chemicals with a broad spectrum of polarities by separately spiking the agents into feed at various levels. Analytical data illustrating the level of contamination at each interval of the multi-step cleanup procedure are presented for each test chemical. Analytical chemical methods and efficiencies of the cleaning steps with the feed admixtures are discussed. The procedure was tested and adopted for use at the National Center for Toxicological Research (NCTR).

Animal Feed↗
PubMed1982

Trace analysis of doxylamine succinate in animal feed, human, urine, and wastewater by GC using a rubidium-sensitized nitrogen detector.

Doxylamine succinate, a drug used as a sleep-inducing agent, an antihistamine, and in a therapeutic formulation taken by pregnant women as an antinauseant, was scheduled for toxicological evaluation as part of a structure activity relationship study, with rats and mice, because a deficiency of such data exists with regard to many antihistamines. Analytical chemical procedures that ensure proper concentration, homogeneity, and stability of the drug in dosed feed, as well as the safety of personnel and the environment, were prerequisites for the toxicological tests. GC methods using a rubidium-sensitized nitrogen detector were developed for analysis of doxylamine succinate in animal feed, human urine, and wastewater at levels as low as 1 ppm, 100 ppb, and 100 ppb, respectively. Sample extracts were cleaned up by liquid-liquid partitioning, followed by additional cleanup on a column of silica gel. Data are presented concerning the stability of the drug in animal feed, extraction efficiencies, and the use of the silica gel cleanup column to separate the caffeine interference from doxylamine in extracts of human urine. Partition values and ancillary data concerning analysis of the drug in feed, by HPLC at levels as low as 10 ppm, are also reported.

Animal Feed↗