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Biomedical subjects

J Williams

Publications and source records attributed to J Williams.

At least 847 records · Page 47Linked to original sources
PubMed1988

Randomized low-dose indomethacin trial for prevention of intraventricular hemorrhage in very low birth weight neonates.

We admitted 36 preterm neonates (600 to 1250 gm birth weight) with normal 6-hour echoencephalograms to a randomized, placebo-controlled prospective trial to determine whether a low dose of indomethacin would prevent germinal matrix or intraventricular hemorrhage and permit adequate urinary output. Between the sixth and tenth postnatal hours, indomethacin (0.1 mg/kg) or placebo was administered intravenously every 24 hours for a total of three doses. Cardiac ultrasound studies to assess the status of the ductus arteriosus were performed at 6 postnatal hours and on day 5. Urinary output, serum electrolytes, serum indomethacin levels, and renal and clotting functions were monitored. No differences in birth weight, gestational age, or Apgar scores were noted between the two groups of infants. Two indomethacin-treated infants and three infants given placebo had significant urinary output difficulties, requiring that the study medication be withheld. Of 19 infants given indomethacin, two had germinal matrix or intraventricular hemorrhage, in comparison with 8 of 17 infants given saline solution (p = 0.02). Of the infants who had a left-to-right patent ductus arteriosus shunt before treatment, 64% of the indomethacin-treated and 33% of the saline solution-treated infants no longer had a patent ductus arteriosus on day 5. Ductal status appeared unrelated to the development of germinal matrix or intraventricular hemorrhage.

Cerebral Hemorrhage↗
PubMed1988

Tendency to display spontaneous incubation does not affect maternal responsiveness in the domestic hen.

Induction of maternal behavior was performed in 63-week-old hens of the JV15 (or "Vedette") strain which had previously exhibited brief incubating phases during the preceding egg-laying period to discover if their maternal behavior differed from that induced in hens who had no previous record of incubating. The degree of maternal behavior exhibited showed large variation among individuals. However, hens with a history of one or more spontaneous, brief incubation bouts and hens without such histories showed similar responsiveness toward chicks and similar levels of general activity. In most of the subjects, the establishment of maternal behavior was accompanied by a significant long-term fall in the plasma levels of luteinizing hormone whereas the plasma levels of prolactin appeared to be unaffected.

Animals↗
PubMed1988

Plasma levels of progesterone in the domestic hen related to the maturation of ovarian follicles, and changes in the secretion of progesterone by granulosa cells cultured for 24 hours.

Hens in their sixth month of lay were injected with a series of doses of ovine LH, either following the oviposition of a mid-sequence egg (which is closely associated with an ovulation), or following the oviposition of the last egg of a sequence. The concentrations of steroid hormones were subsequently measured by radioimmunoassay in blood withdrawn at intervals after injection. No changes were observed in the concentrations of either testosterone or 17 beta-oestradiol, irrespective of the dose of LH or the stage of the ovulatory cycle. An increase in delta-4-androstenedione was observed in all cases. This increase was minimal and unrelated to the dose of LH at the mid-sequence stage, but a dose-response relationship was observed in hens injected following the terminal oviposition of a series. Consistent, dose-related changes in the concentrations of progesterone in plasma were found at both stages of the ovulatory cycle, and the magnitude of these changes was 3.5-5 times greater than those observed for androstenedione. Granulosa cells from the first, second and third ovarian follicles were dispersed by collagenase and stimulated with ovine LH either immediately or following a 24 h pre-incubation in medium 199. The amount of progesterone released into the medium after 3 h was assessed by radioimmunoassay. A progressive decrease in this response was observed in cells derived from the first to the third follicles in all cases. Cells challenged after 24 h always showed increased responses, cells from the second follicle secreted similar amounts of progesterone as cells from the first follicle that were challenged immediately, without pre-incubation. The responses obtained after 24 h were attenuated if no bovine serum albumin was present in the medium, or if ovine LH had been present in the medium continuously. These results are interpreted as evidence for an increase in the secretion of progesterone by the granulosa cells of the hen which is linked to the maturation of the follicle. The final stages of this maturation may proceed in the absence of LH.

Androstenedione↗
PubMed1988

Evaluation of chromatographic and kit immunoassay techniques for the measurement of theophylline in serum: a study based on external quality assurance measurements.

The accuracy and precision of assay techniques used to measure theophylline concentrations in human serum were compared using data from 96 samples from the Heathcontrol external quality assurance scheme. Abbott TDX had the highest precision, with a mean coefficient of variation (CV) of measurements of 6.4%, and Ames Fluorostat was most accurate, with a mean bias of +0.1%. Differences between the better techniques, however, were not significant. The Beckman ICS assay gave the lowest precision (CV 9.3%) and, in addition, produced the highest proportion (7.5%) of rejected observations greater than 3 standard deviations from the sample mean. The least accurate method was radioimmunoassay, with a -9.9% bias. Measurements from two samples spiked with paraxanthine demonstrated that 76% of laboratories using high-pressure liquid chromatography (HPLC) were unable to distinguish between paraxanthine and theophylline. The +4% bias observed at low concentrations and the high variability (CV 8.3%) of measurements made by HPLC were thus attributed to interference by paraxanthine present in the sample matrix. Discriminant analysis of a range of HPLC column and mobile phase parameters indicated that separation of theophylline and paraxanthine was achieved by the use of lower flow rates with mobile phases of solvent mixtures with lower proton donator selectivity.

Chromatography, High Pressure Liquid↗
PubMed1988

Alterations in immunologic measurements in patients experiencing early hepatic allograft rejection.

We compared lymphocyte subsets, the T4:T8 ratio, and assays of lymphocyte function in 11 recipients of hepatic allografts who showed signs of early graft rejection (less than 3 weeks after transplant) with 13 patients who had no evidence of graft rejection. Both patient groups had similar values for lymphocyte subsets, lymphocyte transformation in the presence of phytohemagglutinin, and in vitro immunoglobulin synthesis prior to allografting. Nonrejectors had a decline in both T3 and T4 cells one week after transplant. Those who had evidence of graft rejection did not show a significant decline in either of these T cell subsets. The T4:T8 ratio declined in 11/13 nonrejectors in the week after transplant but in only 4/11 rejectors (P less than 0.05). Monitoring immunologic markers in blood may represent a means of determining which subjects are at greatest risk for developing early hepatic allograft rejection.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1988

Morphologic features of rejection in long-surviving canine small bowel transplants.

We studied morphologic features of small bowel transplants in 25 dogs immunosuppressed by cyclosporine, and preoperative graft irradiation. Graft and host bowel were compared with respect to multiple histologic parameters in a blinded analysis. A lymphoplasmacytic infiltrate in nerves and vessels in submucosa and muscle was present in 18 graft bowels and only 3 host bowels, suggesting that these findings represent a cellular rejection reaction. The other histologic parameters were the same in graft and host bowel. Although the dogs did not exhibit clinical signs of rejection, end-stage scarring of the bowel and death occurred in 6 dogs. The animals did not develop systemic graft-verus-host reaction. These findings indicate that under cyclosporine therapy, a subclinical rejection reaction persists deep in the wall and may remain undetectable in mucosal biopsies, but may progress to destroy the graft.

Animals↗
PubMed1988

Molecular analysis of a pathogenicity locus in Pseudomonas syringae pv. syringae.

One of the chromosomal regions of Pseudomonas syringae pv. syringae encoding pathogenicity factors had been mapped into a 3.9-kilobase-pair fragment in previous studies. Promoter probe analysis indicated the existence of a promoter near one end of the fragment. DNA sequencing of this fragment revealed the existence of a consensus promoter sequence in the region of the promoter activity and two open reading frames (ORFs) downstream. These ORFs, ORF1 and ORF2, encoded putative polypeptides of 40 and 83 kilodaltons, respectively. All ORF1::Tn5 as well as ORF2::Tn5 mutant strains were nonpathogenic on susceptible host bean plants and were unable to elicit hypersensitive reactions on nonhost tobacco plants. The deduced amino acid sequence of the 83-kilodalton polypeptide contained features characteristic of known integral membrane proteins. Fusion of the lacZ gene to ORF2 led to the expression of a hybrid protein inducible in Escherichia coli. The functions of the putative proteins encoded by ORF1 and ORF2 are unknown at present.

Amino Acid Sequence↗
PubMed1988

Adenovirus type 12 E1B 19-kilodalton protein is not required for oncogenic transformation in rats.

The adenovirus type 12 mutants in700 and pm700 carry site-specific mutations within the reading frame encoding the E1B 19-kilodalton protein (19K protein) which prevent the production of the intact 19K protein. In cultures of human A549 cells, these mutants grow just as well as the wild-type virus does, but they display a large-plaque (lp), cytocidal (cyt) phenotype. DNA in these infected cells is not degraded, but at late times in human KB cells infected by the mutants, the mutants display a DNA degradation (deg) phenotype. The transformation phenotype of these mutants is also host range. Although the mutants are defective for transformation of the 3Y1 rat cell line, they transform rat and mouse primary kidney cells in vitro at wild-type efficiency and are capable of inducing tumors in rats. These results support the view that the type 12 E1B 19K protein is not obligatory for oncogenic transformation.

Adenovirus Early Proteins↗
PubMed1988

Silastic catheters for antibiotics in cystic fibrosis.

A randomised comparison of percutaneous Silastic catheters and conventional intravenous cannulae for giving intravenous antibiotics in patients with cystic fibrosis showed that Silastic catheters were favoured by the patient, lasted longer, and had fewer complications.

Adolescent↗
PubMed1988

Faecal chymotrypsin: a reliable index of exocrine pancreatic function.

Simultaneous measurements of duodenal and faecal chymotrypsin were made in 30 children aged 3 weeks to 14 years. Apparent chymotrypsin secretion rates measured after stimulation with pancreozymin were compared with the mean faecal chymotrypsin concentration derived from three stool specimens collected at random within 72 hours of the intraduodenal test. In the 25 children who responded to pancreozymin stimulation the mean faecal chymotrypsin concentration was significantly positively correlated with the apparent chymotrypsin secretion rate. Correlation using single specimen stools collected at random was appreciably poorer. In the five children with undetectable or only traces of chymotrypsin in the duodenum after stimulation, the mean faecal chymotrypsin concentrations were only 3-10% of the lower limit of the reference interval. In a second group of 46 children with cystic fibrosis proved by sweat tests and clinical evidence of malabsorption, the chymotrypsin concentration measured in a single stool specimen collected at random was unequivocally subnormal in each case. Faecal chymotrypsin measurement is a rapid, simple, cheap, readily repeated, non-invasive test of high specificity and sensitivity. Faecal chymotrypsin should be measured before contemplating intraduodenal tests of pancreatic function.

Adolescent↗
PubMed1988

Sweat tests and flucloxacillin.

Sweat tests were carried out on 14 patients with cystic fibrosis and 14 controls when on no antibiotics and when taking oral flucloxacillin. No significant differences in results were obtained for either group whether on or off antibiotics. Oral flucloxacillin does not affect sweat electrolytes and is not a contraindication to sweat testing.

Adolescent↗
PubMed1988

Neonatal screening for cystic fibrosis in Wales and the West Midlands: 1. Evaluation of immunoreactive trypsin test.

A study programme was set up in Wales and the West Midlands to evaluate serum immunoreactive trypsin screening for cystic fibrosis in neonates using blood spots collected for metabolic screening. By screening half the blood spots from each area, it was hoped to generate two comparable groups of fibrocystic children; those detected by screening and those not screened who would be diagnosed clinically. Over almost three years, more than 120,000 specimens were screened and 37 infants detected with cystic fibrosis. Four additional fibrocystic patients were missed on screening: two had negative immunoreactive trypsin values, of which one had meconium ileus, and two, although giving initial positive tests, were negative on follow up. Excluding infants known to be at risk, comparison of the numbers of children detected in the screened and unscreened groups showed more than a two-fold difference in favour of the screened group. There may be a large number of undiagnosed fibrocystic patients in the general population.

Clinical Enzyme Tests↗
PubMed1988

The clinical use and measurement of theophylline.

This report reviews the clinical use, metabolism and toxicity of theophylline (Section 1). Current chromatographic and immunoassay methods for theophylline measurement are discussed and practical methods using high-performance liquid chromatography are described (Section 2). Results from the UK National scheme for theophylline quality control and from an experiment to investigate the degree of interference by 1,7-dimethylxanthine in routine assays for theophylline are discussed in Section 3.

Humans↗
PubMed1988

Quality of urograms in infants: a comparison of sodium diatrizoate, metrizamide and iohexol.

A consecutive series of 314 intravenous urograms performed in infants were reviewed and assessed for quality. The first 106 examinations were performed using sodium diatrizoate (Hypaque 270) as the contrast medium, the next 98 patients received metrizamide (Amipaque 280) and the final 110 received iohexol (Omnipaque 300). Thirty-five patients had to be excluded from the study for a variety of reasons, after which there were totals of 98 in the diatrizoate, 90 in the metrizamide and 91 in the iohexol groups. Assessing quality in terms of nephrographic and pyelographic density, sodium diatrizoate was found to be better than the non-ionic agents. Although the differences reached statistical significance they are small and unlikely to affect the information obtained in clinical practice. There was no difference in overall quality between metrizamide and iohexol. Comparing the degree of pyelographic distension and ureteric visualization using the three agents, no difference was found between the groups.

Diatrizoate↗
PubMed1988

Diagnosis of pulmonary strongyloidiasis by bronchoalveolar lavage.

Bronchoalveolar lavage was performed on a patient with disseminated strongyloidiasis and 4.5 X 10(7) cells/65 ml of lavage fluid were recovered. Eighty-five percent of cells were polymorphonuclear leukocytes; 15 percent were pulmonary alveolar macrophages. Rhabditiform larvae (1 X 10(4)) were recovered in 65 ml of lavage fluid. This is the first report of bronchoalveolar lavage used in diagnosing disseminated strongyloidiasis.

Bronchoalveolar Lavage Fluid↗