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Biomedical subjects

J Wild

Publications and source records attributed to J Wild.

At least 91 records · Page 5Linked to original sources
PubMed1992

Higher multiple births and the modern management of infertility in Britain. The British Association of Perinatal Medicine.

OBJECTIVE: To assess prospectively the number of triplet and higher multiple births born in 1989 and their methods of conception. To assess obstetric factors and the effect of these pregnancies on neonatal medical services. DESIGN: All consultant paediatricians received a monthly card asking whether they had been involved in the management of triplet and higher multiple pregnancies delivered after 22 weeks gestation. Detailed questionnaire sent to those giving a positive response. SETTING: British Paediatric Surveillance Unit organized mailings to all members of the British Paediatric Association working in the British Isles. SUBJECTS: 156 pregnancies resulting in 482 babies (143 triplets, 12 quadruplets and 1 quintuplet set). These data were compared to nationally collected OPCS data. MAIN OUTCOME MEASURES: Method of conception, obstetric performance, neonatal outcome. RESULTS: Of the 156 pregnancies, 47 (31%) were conceived naturally, 52 (34%) had ovarian stimulation (usually with clomiphene or gonadotrophins) 37 (24%) had IVF and 17 (11%) GIFT. All quadruplet and quintuplet pregnancies were established after assisted reproduction. Mothers who had had IVF were significantly older than those who had ovulation induction alone. The median gestation at birth was 33 weeks. Overall 181 (40%) of the babies required intensive care for a median duration of 5 days. The perinatal mortality of the triplets alone and quads and quins together was 70 and 104 per 1000 respectively. CONCLUSIONS: Assisted reproduction is the major cause of triplets and higher multiple births and ovarian stimulation is the single most important technique currently in use. These babies are very likely to be born pre term and make considerable demands on neonatal intensive care facilities.

Adult↗
PubMed1992

DnaK, DnaJ, and GrpE are required for flagellum synthesis in Escherichia coli.

The DnaK, DnaJ, and GrpE heat shock proteins are required for motility of Escherichia coli. Cells deleted for dnaK or dnaJ, or with some mutations in the dnaK or grpE gene, are nonmotile, lack flagella, exhibit a 10- to 20-fold decrease in the rate of synthesis of flagellin, and show reduced rates of transcription of both the flhD master operon (encoding FlhD and FlhC) and the fliA operon (encoding sigma F). Genetic studies suggest that DnaK and DnaJ define a regulatory pathway affecting flhD and fliA synthesis that is independent of cyclic AMP-catabolite gene activator protein or the chemotaxis system.

Bacterial Proteins↗
PubMed1992

Involvement of Fis protein in replication of the Escherichia coli chromosome.

We report evidence indicating that Fis protein plays a role in initiation of replication at oriC in vivo. At high temperatures, fis null mutants form filamentous cells, show aberrant nucleoid segregation, and are unable to form single colonies. DNA synthesis is inhibited in these fis mutant strains following upshift to 44 degrees C. The pattern of DNA synthesis inhibition upon temperature upshift and the requirement for RNA synthesis, but not protein synthesis, for resumed DNA synthesis upon downshift to 32 degrees C indicate that synthesis is affected in the initiation phase. fis mutations act synergistically with gyrB alleles known to affect initiation. oriC-dependent plasmids are poorly established and maintained in fis mutant strains. Finally, purified Fis protein interacts in vitro with sites in oriC. These interactions could be involved in mediating the effect of Fis on DNA synthesis in vivo.

Bacterial Proteins↗
PubMed1992

Microendoscopic observations of the hemodynamics in the rabbit ciliary processes.

The in vivo hemodynamics of the ciliary process vasculature in the albino rabbit were studied with an improved technique of intraocular microendoscopy. The spreading pattern and velocity of the dye front has been observed in defined vessel segments following intracarotid injection of Evans Blue. In the anterior portion of the ciliary processes a "thoroughfare channel" (bypass) was found leading from the arteriolar tree directly into the marginal venule bypassing the capillary network of the ciliary processes. This bypass is characterized by a higher blood flow velocity (1.5-3mm/sec) than was found for the capillary network (0.8-1mm/sec). A stoppage of blood flow was observed in the capillary network at 45-50mmHg after step-wise elevation of intraocular pressure (IOP): blood flow was not stopped in the thoroughfare channel until IOP values of 55-60mmHg were reached. Intraarterial administration of vasoconstrictive agents could lead to a complete stoppage of blood flow in the capillary net whereas the marginal route often remained patent.

Animals↗
PubMed1992

SLP assay: a rapid assay for detection of red blood cell antibodies in the serology of pregnancies.

A rapid manual test for the detection of red cell antibodies called SLP assay has been developed and compared with the sensitivity of the antiglobulin assay. Acid-soluble proteins (SLP) from human leukocytes cause aggregation of human red blood cells. SLP represents a group of proteins consisting of 5 fractions of different positively charged macromolecules, which are able to reduce the negative charge of the red cells. Reduction of the negative charge results in a nonspecific hemagglutination of different strengths, depending on the SLP fractions used. This hemagglutination can be reversed by neutralizing the SLP with heparin. In the case of blood group-antibody-mediated aggregation the hemagglutination is nonreversible despite neutralization with heparin and remains stable for several hours. Because of the high sensitivity of the SLP assay all blood group antibodies from the IgM type as well as from the IgG type are detectable even in low concentrations. The sensitivity of the SLP assay is comparable to the antiglobulin assay.

ABO Blood-Group System↗
PubMed1990

One heart, two bodies: insight from the transplanted heart and its new electrocardiogram.

Cardiac transplantation provides a unique opportunity to record the electric field generated by a human heart in a new somatic environment. By examining pre- and posttransplantation electrocardiograms (ECGs), it is possible to address questions on the effect of rotation of the heart on its long axis on the surface ECG, the effect of thoracic anatomy on ECG voltage and predisposing factors for conduction defects observed after transplant surgery. To examine these questions, we reviewed a series of 35 matched donor and recipient ECGs. There were no differences in the mean height of the donors and recipients, but age, weight and body surface area were higher in the recipients (p less than 0.025). We found no significant differences in the mean heart rate or precordial voltage but the PR and QT intervals were shorter (p less than 0.025), and the precordial transitional zone was more to the left after transplantation (p less than 0.0005). New evidence of right bundle branch delay was found in 11 recipients and this was not related to pretransplantation hemodynamic factors or the period of ischemic arrest. Thus, there is indeed an anatomic basis for the ECG determination of clockwise rotation of the heart when the precordial transition zone is to the left. Age and body habitus, per se, do not appear to affect precordial voltage and evidence of right bundle delay in the transplant recipient appears to be related to the altered position of the heart and not to injury or changes in right ventricular hemodynamics.

Adolescent↗
PubMed1990

Bromocriptine as an adjuvant to cyclosporine immunosuppression after heart transplantation.

Prolactin, a pituitary hormone, has been shown to have an active role in the regulation of the immune system. Prolactin receptors have been described on the membrane of lymphocyte cells, and competitive binding to these receptors by cyclosporine and circulating prolactin has been demonstrated. Experimental evidence suggests a synergistic effect of cyclosporine and bromocriptine, an inhibitor of pituitary release of prolactin, on immunosuppression. Between July 1986 and January 1988, 54 patients were randomly assigned to two groups of immunosuppression treatment. Thirty patients (group 1) were administered cyclosporine, azathioprine, and prednisone and 24 patients (group 2), a modified protocol aimed at decreasing the level of circulating prolactin by adding bromocriptine to the immunosuppression regimen. The two groups were similar in regard to age, preoperative diagnosis, and duration of follow-up. Minimal side effects related to bromocriptine were observed. The overall incidences of rejection and infection were similar, although actuarial analysis showed that freedom from these complications among patients treated with bromocriptine was significantly higher throughout the first 2 months after heart transplantation compared with that of patients in the control group. Other variables such as serum cyclosporine levels and lymphocyte counts were similar in both groups. In conclusion, suppression of circulating prolactin by bromocriptine appears to improve the immunosuppressive effect of cyclosporine, at least during the early postoperative period when the risk of rejection and infection is higher, and could be a promising avenue to successful hormonal manipulations of the immune process after organ transplantation.

Actuarial Analysis↗
PubMed1990

Association of anti-DNA idiotype markers with clinical and serological manifestations in patients with systemic lupus erythematosus.

Serum levels of 6 anti-DNA antibody idiotypes were measured in 65 consecutive patients with systemic lupus erythematosus (SLE) and 45 healthy subjects. Five of the 6 idiotypes were elevated in SLE sera compared to the normal controls (p less than 0.005). Analysis of the associations of the idiotypes with clinical, hematological, and serological characteristics revealed that significantly decreased serum levels of 3 idiotypes (103.1, 100, and 1305) were associated with nephritis and that one of these idiotypes (103.1) was also associated with discoid rash. An association of lowered levels of 3 idiotype markers (604, 1305, and 1400) was also observed with the presence of lupus anticoagulant and anticardiolipin antibodies. Serial studies in individual patients with SLE nephritis failed to show a close correlation of serum idiotype levels with the degree of proteinuria, creatinine clearance, anti-DNA antibody, or complement values. The association of decreased levels of specific idiotypes with the presence of nephritis, discoid rash, and antiphospholipid antibodies suggests the participation of these antibodies in the pathogenesis of disease.

Adolescent↗
PubMed1989

In vivo characterization of the absorption and biotransformation of pteroylmonoglutamic acid in man: a model for future studies.

HPLC-EC has been used to measure the appearance of 5-CH3-H4 folic acid in human plasma following oral administration of folic acid. The process was found to be saturable in accordance with Michaelis-Menten kinetics. The apparent Km for this enzyme system indicates that low doses of oral folic acid are rapidly converted into 5-CH3-H4 folic acid, an observation consistent with the needs of intestinal absorption of essential trace nutrients. The appearance of L. casei active folate in plasma was not rate-limited and showed a biphasic relationship to dose. Preparative HPLC combined with L. casei bioassay demonstrated that most of the L. casei active folate appearing in plasma following a 20,000-micrograms dose of folic acid was due to the unmodified vitamin, only 5.6% being due to 5-CH3-H4 folic acid and with no detectable contribution from 5-CHO-H4 folic acid. The absorption characteristics of the system seem consistent between and within subject(s). No relationship could be demonstrated between predose levels of plasma 5-CH3-H4 folic acid and total folate in erythrocytes, which reflect the status of transport and storage forms of the vitamin, respectively.

Absorption↗
PubMed1989

Prevalence of neural tube defects in the Yorkshire Region.

The birth prevalence of neural tube defects (NTD) in the Yorkshire Region was determined for 1985 and 1986 by ascertainment of cases in live-and stillborn babies and of pregnancies terminated for NTD. Sixty-seven cases of anencephaly, 82 of spina bifida and 11 others were identified, a prevalence of 1.54 per 1000 total births. Eighty-eight per cent of pregnancies associated with anencephaly and 48 per cent of those with spina bifida were terminated.

Cross-Sectional Studies↗
PubMed1989

Neural tube defect recurrence after 'partial' vitamin supplementation.

A total of 227 mothers enrolled for periconceptional multivitamin supplementation because of previous neural tube defect (NTD) births took vitamins for less than the recommended minimum period (at least 28 days before conception until two menstrual periods have been missed). Of 213 examined infants/fetuses born to these partially supplemented mothers, two had NTD, one of whom followed four previous NTDs. The observed NTD recurrence rate is similar to that observed in fully supplemented mothers. A further 14 mothers started supplements before the second missed period but after the normal time of neural tube closure. Three of their offspring had NTD. The significance of this apparently high recurrence rate is discussed.

Ascorbic Acid↗
PubMed1989

Biotransformation of pteroylmonoglutamic acid during absorption: implications of Michaelis-Menten kinetics.

Previously reported work from this laboratory has shown that, in man, the formation of plasma 5-methyltetrahydrofolic acid (5MeTHF) from orally administered pteroylmonoglutamic acid (PGA) obeys Michaelis-Menten kinetics. The regression equation obtained from a plot of the reciprocal amount of 5MeTHF formed (micrograms per litre plasma/min) as a function of reciprocal amount of PGA administered (micrograms/kg body weight) provides a useful means of calculating the improved efficiency of 5MeTHF formation by dividing the total dose of PGA into smaller doses.

Adult↗
PubMed1987

Longitudinal study of height and weight at adolescence.

A longitudinal study through puberty of the height and weight of 96 boys and 102 girls in schools in and around the city of Leeds was conducted. Data for height and weight and height and weight velocities are presented, which are based on chronological age and on age relative to the age of peak height velocity. Comparison was made with the Tanner standards: male puberty developed a little later but growth continued longer, so that the adult men were taller and heavier. Girls showed a similar timing of puberty to the Tanner standards but were lighter at all ages and ultimately slightly taller as growth was not completed until later. It is important to know the pubertal state when interpreting growth changes in children.

Adolescent↗
PubMed1987

Naltrexone treatment for postconcussional syndrome.

Two patients with postconcussional syndrome whose most severe symptoms were blackouts, headaches, and amnesia episodes appeared to respond to naltrexone. Because life-saving emergency trauma services are widely available, it is likely that the incidence of postconcussional syndrome will increase.

Accidental Falls↗
PubMed1987

Two distinct types of mutations conferring to Escherichia coli K12 capability of D-tryptophan utilization.

We showed that the ability of Escherichia coli K12 tryptophan auxotrophs to utilize D-tryptophan as a substitute for L-tryptophan may result from two types of mutations. The first type consisted in changes in the dadR regulatory site of the dad operon increasing the synthesis of D-amino acid dehydrogenase. The mutations of the second type mapped within the dad A structural gene. They changed the apparent substrate specificity of D-amino acid dehydrogenase. We suppose that the change may be due to an altered enzyme structure which make it more accessible to D-tryptophan.

Alanine↗
PubMed1986

Recurrent neural tube defects, risk factors and vitamins.

Data from our trial of periconceptional vitamin supplementation for the prevention of neural tube defects have been analysed to assess the influence of various factors on recurrence rates of neural tube defect. Our data suggest that the risk of recurrence of neural tube defect is influenced by the number of previous neural tube defects, area of residence, immediately prior miscarriage, and interpregnancy interval. None of these factors, however, contributed any significant differential risk between supplemented and unsupplemented mothers. Hence we conclude that the highly significant difference in recurrence rates of neural tube defect between supplemented and unsupplemented mothers was due to vitamin supplementation.

Abortion, Spontaneous↗
PubMed1986

Human-human hybridoma autoantibodies with both anti-DNA and rheumatoid factor activities.

Human hybridomas have been produced by fusing peripheral blood lymphocytes from patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) with the GM 4672 human cell line. 262 hybridoma clones from the fusions of four RA and five SLE patients were screened for binding to denatured DNA (dDNA), native DNA, and the Fc fragment of human IgG (HIgG). Of the 17 hybridoma antibodies (nine RA, eight SLE) selected for strong binding to denatured DNA, Fc, or both, five reacted with dDNA only, one with Fc only, and eight with both dDNA and Fc. Hybridoma supernatants exhibiting dual reactivity were absorbed over HIgG and bovine serum albumin (BSA)-Sepharose immunoabsorbent columns. The reactivities to both DNA and HIgG were completely removed by the HIgG column but unaffected by passage over the BSA column, and both DNA binding and rheumatoid factor activities were recovered in the acid eluates from the Sepharose-IgG column. The binding of dual reactive hybridoma autoantibodies to the Fc fragment of HIgG was specifically competed by dDNA and HIgG, providing additional evidence that one antibody may be capable of reacting both as a rheumatoid factor and as an anti-DNA antibody.

Antibodies, Antinuclear↗