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Biomedical subjects

G W Bates

Publications and source records attributed to G W Bates.

At least 55 records · Page 3Linked to original sources
PubMed1987

The purification of lactoferrin from human whey by batch extraction.

The isolation of lactoferrin from human whey has been accomplished using a rapid two-step procedure. The lactoferrin is directly adsorbed to cellulose phosphate by batch extraction and eluted by a stepped salt and pH gradient. The major impurity, a low-molecular-weight fraction, is quickly removed by gel filtration. The recovered lactoferrin has a purity of about 96%. The yield of lactoferrin averaged 80%. This method of lactoferrin purification greatly reduces the labor and time required, and the procedure is easily scaled to any volume of starting material.

Chromatography, Gel↗
PubMed1987

Role of transmigration and abnormal embryogenesis in ectopic pregnancy.

Transmigration of ovum and/or sperm may occur, as deduced by the presence of EP in the fallopian tube contralateral to the corpus luteum. The frequency of occurrence of transmigration is relatively low, and, in many cases, other routes of ovum and sperm transport (i.e., intrauterine migration, tubal recanalization, fistula formation) may lead to the ectopic implantation site. In our view, the percentage of abnormal embryos associated with EP is no different from those associated with spontaneous abortions of intrauterine origin. Embryos from spontaneous abortions-of either intrauterine or extrauterine origin-seem to have more abnormalities than embryos from induced abortions. Other etiologic factors such as tubal disease, strictures of the fallopian tube, or endocrinopathies seem to contribute more significantly to the incidence of EP than does abnormal embryogenesis.

Abdomen↗
PubMed1986

The exchange of Fe3+ between pyrophosphate and transferrin. Probing the nature of an intermediate complex with stopped flow kinetics, rapid multimixing, and electron paramagnetic resonance spectroscopy.

A detailed study of the exchange of Fe3+ between pyrophosphate and human serum transferrin was undertaken to test the hypothesis of a generalized reaction route for exchange of Fe3+ between transferrin and chelators. The initial rate of Fe3+ transfer from pyrophosphate to apotransferrin-CO2-3 is highly sensitive to the pyrophosphate to iron ratio with a maximal rate being observed at a ratio of 3:1, consistent with the presence of slowly reactive polymeric species at ratios less than 3:1 as revealed by EPR and kinetic measurements. At a ratio of 4:1 the reaction is distinctly biphasic. The rapid first phase results in the formation of an intermediate postulated as a mixedligand complex of the type PPi-Fe3+-transferrin-CO2-3. The intermediate has a distinct EPR spectrum and an absorption spectrum similar to that of Fe3+-transferrin-CO2-3, but with a spectral maximum at 450 nm rather than 465 nm. The second phase principally arises from the slow reaction of polymeric iron-pyrophosphate with the apoprotein and has contributions from the breakdown of the intermediate formed in the first phase. The rate of formation of the intermediate shows a hyperbolic dependence on NaHCO3 and apotransferrin concentrations, the latter suggesting a rate-limiting labilization of Fe3+(PPi)3, perhaps to form species of the type Fe3+(PPi)2, prior to attack by apotransferrin-CO2-3. Multimixing stopped flow spectrophotometry was employed to test the chemical reactivity of the Fe3+ to reduction at various times during the first phase. Surprisingly, a diminution of reactivity of 1000-fold was noted after only 2% of the first phase was completed, indicating a fast initial reaction which is not observed by normal rapid flow spectrophotometry. This initial reaction may involve the binding of iron-pyrophosphate to allosteric sites on the protein. The kinetics of iron removal from Fe3+-transferrin-CO2-3 by PPi are consistent with a rate-limiting conformational change in the protein as proposed earlier.

Apoproteins↗
PubMed1986

Stable transformation of tobacco by electroporation: evidence for plasmid concatenation.

Electroporation (electric field-mediated DNA transfer) of tobacco protoplasts in the presence of the linearized plasmid pMON200 has led to the formation of transgenic plants. Defined electric shocks were delivered by capacitive discharges with readily available, low-cost electrical components. This transformation procedure is simple and efficient and may suggest a quick method for determining the appropriate electric fields for new cell systems. An optimal transformation frequency of 2.2 X 10(-4) (based on the number of cells subjected to the shock) was obtained with a single 2000-V/cm, 250-microseconds-duration capacitive discharge. Calli transformed to kanamycin resistance have been regenerated into whole plants. Southern blots of DNA from the transgenic plants demonstrate the integration of the selectable marker gene (neomycin phosphotransferase) at single or multiple genomic sites. In some cases, the plasmid appears to be integrated intact; in others, it is rearranged. The blots also provide evidence of plasmid recircularization and/or the formation of head-to-head and head-to-tail concatemers in most of the plants analyzed. Although some plants apparently have multiple integration sites, analysis of progeny obtained by self-fertilization of the transgenic plants indicates that the kanamycin-resistance marker is inherited as a single dominant gene.

Chromosome Mapping↗
PubMed1986

Treatment of persistent ectopic pregnancy with methotrexate and leukovorum rescue: a case report.

The incidence of ectopic pregnancy is increasing in the Western world, and this reproductive complication has had an adverse impact on subsequent fertility. Advances in the surgical treatment of ectopic pregnancies have been designed to preserve future reproductive potential, but conservative tubal surgery may fail to completely remove the trophoblast. Described is a case of persistent ectopic pregnancy successfully treated with methotrexate.

Adult↗
PubMed1986

Potential role of in vitro iron bioavailability studies in combatting iron deficiency: a study of the effects of phosvitin on iron mobilization from pinto beans.

Iron deficiency and iron overload affect one billion people worldwide. Treatment of iron malnutrition can be enhanced by an understanding of iron bioavailability from the diet. We have focused on the development of in vitro methods for determining iron bioavailability in the hopes of providing both an understanding of the chemical basis leading to the inhibition or enhancement of iron absorption and the provision of methodologies which will allow nutritionists around the world to ascertain iron bioavailability of local foods and food combinations. The study reported here focuses on the effects of phosvitin, a suspected inhibitor of iron absorption found in egg yolks, on the chemistry of iron during the in vitro enzymatic digestion of pinto beans. Three basic types of information were obtained. First, the total soluble iron was determined during in vitro enzymatic digestion under simulated oral, gastric (pH 2) and duodenal (pH 6) conditions. Phosvitin was found to have a strong solubilizing effect at pH 6 and pH 2 when in the presence of ascorbate. Pyrophosphate also leads to high iron mobilization. A second approach is to determine the static Fe2+ and Fe3+ concentrations following in vitro enzymatic digestion of pinto beans at pH 2 and pH 6. Ascorbic acid enhanced the total soluble iron at both pH values, however, only at pH 2 was a large proportion of the iron found in the Fe2+ state and then only in the presence of phosvitin but not pyrophosphate. A third approach is to determine the amount of Fe2+ formed in the digestive supernatant during a 10-min incubation with ferrozine.(ABSTRACT TRUNCATED AT 250 WORDS)

Ascorbic Acid↗
PubMed1986

Insemination with fresh donor semen.

Factors influencing the probability of conception after artificial insemination with donor semen were investigated in a series of 80 infertile couples. Overall, 46 pregnancies were achieved for a crude pregnancy rate of 58%. Life table analysis showed a cumulative probability of conception of 97.1% at the end of 12 cycles and an average fecundability of 15.1%. These results were achieved using a single insemination per cycle and individualizing the day of insemination based on the woman's basal body temperature. Women who had been pregnant previously had a significantly better fecundability than nulligravid women (P less than .05). The overall rates of conception in those women who required therapy for ovulatory dysfunction were the same as normal women although the fecundability was somewhat lower. Women who had abdominal pathology had an overall conception rate of 23%.

Cervix Mucus↗
PubMed1985

The interaction of resealed reticulocyte ghosts with Fe3+-transferrin-CO3(2-).

The present studies were designed to investigate the interaction of Fe3+transferrin-CO3(2-) with the transferrin receptors of the resealed reticulocyte ghost and to assess the degree to which the iron release reaction can be reconstituted in resealed ghosts supplemented with entrapped cytoplasmic components. Reticulocyte, but not erythrocyte, ghosts displayed an intact Fe3+transferrin-CO3(2-) binding capability. When ATP, NADH and ferritin were included during the resealing process, some iron release to the ghosts was observed.

Adenosine Triphosphate↗
PubMed1985

Amniotic fluid embolism: prophylaxis with heparin and aspirin.

The thromboplastic activity of amniotic fluid (AF) from women in labor may be a significant factor in amniotic fluid embolism (AFE) and obstetric disseminated intravascular coagulation (DIC). Infusion of AF from women in labor into laboratory animals was found to depress the platelet count, as seen in DIC. In this study we also investigated the ability of heparin and aspirin to block the thromboplastic activity and thrombocytopenia subsequent to AF infusion. In animals, heparin prophylaxis before infusion of AF prevented thrombocytopenia, whereas aspirin prophylaxis did not. Heparin prophylaxis may be useful in the management of coagulation defects associated with AFE and labor.

Animals↗
PubMed1985

Plasma prolactin concentrations and pregnancy-induced hypertension.

Human prolactin (PRL) has been related to various pathologic disorders known to be associated with osmoregulation and hypertension. In this study, we compared changes in plasma PRL concentrations in normal pregnant patients to those in patients with severe pregnancy-induced hypertension (PIH). Comparison of plasma PRL concentrations collected antepartum, at delivery, and 48 hours postpartum failed to distinguish women with PIH from those without. Only women with PIH, however, showed a significant rise in systemic PRL concentrations between admission to the study and delivery. Antepartum abnormalities in plasma PRL concentrations associated with PIH may not have been detected because of diurnal variations in PRL secretion.

Adult↗
PubMed1985

A technique for uterine conservation in adolescents with vaginal agenesis and a functional uterus.

Vaginal agenesis in association with a functional uterus occurs infrequently, and usually presents in adolescents. To preserve reproductive function, the uterus must be conserved, and a vagina must be constructed in one operative procedure. The authors describe a surgical technique that combines a modified McIndoe vaginoplasty with uterine conservation in which a special stent is fabricated to insert in the uterine cervix and the neovagina. Factors that must be considered when choosing between a hysterectomy and a uterine conservation procedure also are discussed.

Cervix Uteri↗
PubMed1984

Management of agenesis of the vagina.

The management of 92 women with vaginal agenesis is presented. All patients were managed by a modified McIndoe procedure. Four women (4 per cent) had intraoperative or postoperative complications, but only one woman had a complication that resulted in failure of vaginal function. We advocate the McIndoe vaginoplasty as the primary technique of management for women with vaginal agenesis.

Adolescent↗