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Biomedical subjects

R Warwick

Publications and source records attributed to R Warwick.

At least 37 records · Page 2Linked to original sources
PubMed1994

Prenatal determination of human platelet antigen type using DNA amplification following amniocentesis.

OBJECTIVES: To demonstrate that fetal human platelet antigen (HPA1) type can be determined, without the need for fetal blood sampling, by amplification of fetal DNA from amniotic fluid cells using polymerase chain reaction and allele specific oligonucleotide hybridisation. DESIGN: Oligonucleotide DNA primers were designed to amplify a portion of the platelet glycoprotein GpIIIa gene which spans the site of the single base change which differentiates HPA1a from HPA1b. Specific oligonucleotides were designed to hybridise either to the amplified HPA1a allele or to the HPA1b allele. Amniotic cells were used as the DNA template both directly and following formal isolation of DNA. Fetal HPA1 type, determined by this method in fifteen pregnancies not at risk of perinatal alloimmune thrombocytopaenia, was compared to typing of fetal blood obtained following cordocentesis. The methodology was then used to HPA type the fetus in two pregnancies at risk of the disease. SETTING: Department of Molecular Biology and Centre for Fetal Care, Queen Charlotte's Hospital. SUBJECTS: Fifteen women undergoing amniocentesis and fetal blood sampling for other indications and two women at risk of perinatal allo-immune thrombocytopaenia whose partners were heterozygotes. RESULTS: In the 15 control cases and the two clinical cases, determination of fetal HPA1 type from amniotic fluid cells agreed with typing of fetal blood. There was no difference in the efficiency of amplification from amniotic fluid cells directly or from isolated DNA. CONCLUSIONS: Fetal HPA type may be reliably determined by amplification of DNA from amniotic fluid cells, eliminating the need for fetal blood sampling or immunoglobulin administration when the fetus is HPA1a negative.

Amniocentesis↗
PubMed1990

Simultaneous assessment of intestinal permeability and lactose tolerance with orally administered raffinose, lactose and L-arabinose.

1. In order to develop an improved differential sugar absorption test for simultaneously assessing intestinal permeability and lactose intolerance, methods were established for determining raffinose, lactose and L-arabinose in human urine. Using NAD(P)H-coupled enzymatic assays and fluorimetry, each sugar was measurable over a concentration range of approximately 3-300 mumol/l in diluted urine specimens. 2. After an overnight fast, 40 normal volunteers drank an iso-osmotic solution containing raffinose, lactose and L-arabinose. The median 5 h urinary sugar excretion was 0.26% of the ingested raffinose, 0.05% of lactose and 17.5% of L-arabinose. 3. In 143 patients with gastrointestinal disease, excretion of both ingested raffinose and lactose was significantly increased in coeliac disease in relapse or in partial remission and in Crohn's disease, but not in the irritable bowel syndrome, coeliac disease in remission or ulcerative colitis. Excretion of lactose, but not raffinose, was increased in patients with mucosal lactase deficiency, whereas excretion of L-arabinose was reduced in all disease groups except ulcerative colitis. 4. Discrimination between diseases was poor when based on individual sugar recoveries, but improved dramatically when excretion was expressed relative to that of L-arabinose. The raffinose/L-arabinose excretion ratio, an index of intestinal permeability, was greater than 0.08 in 15/15 untreated coeliac patients but less than 0.06 in all normal subjects and in 9/9 lactase-deficient patients, 15/16 recovered coeliac patients, 5/6 patients with ulcerative colitis, 13/16 patients with Crohn's disease and 61/62 patients with irritable bowel syndrome.

Adolescent↗
PubMed1989

Changes in protein C and free protein S during pregnancy and following hysterectomy.

Two longitudinal studies were undertaken to measure the naturally occurring coagulation inhibitors, protein C and protein S, in females who were either pregnant or who were undergoing hysterectomy. Functional and immunological protein C and free protein S were assayed. During pregnancy, protein C levels remained unchanged except for a small increase in protein C antigen at 28-32 weeks gestation. The free protein S fell significantly and progressively during pregnancy, although only in about one-third of patients did the level fall below the normal range. In the hysterectomy study, a significant fall in protein C occurred on days one and three after surgery but had returned to normal by the time of discharge (days 7-10). A small rise in free protein S was observed at time of discharge, but this factor was otherwise unchanged. We conclude that the changes observed may contribute to the hypercoagulable state which is associated with pregnancy or major surgery.

Adult↗
PubMed1986

Anatomy--analysis and synthesis.

Scientific knowledge is a continuum, and anatomy is a part of this subject to the same methods, principles, and the need of synthesis, both within anatomy and with other syntheses. Western science is the spearhead of human progress in understanding the universe around us and the world of Earth, from which we cannot escape. Science may also, in its power of synthesis, bringing together not only those who practise it but also uniting the nations. Excellent as are the applications of science in technology, knowledge has its own value in producing a synthesis of human awareness,--and also it may prevent us from ruining the Earth, which is our only possible home.

Anatomy↗
PubMed1983

Monosaccharide absorption and water secretion during disaccharide perfusion of the human jejunum.

During jejunal perfusion of normal subjects with isotonic mannitol-saline containing glucose, maltose or sucrose (112 mmol/l), monosaccharide absorption from disaccharides was greater than expected from the intraluminal concentration of free monosaccharides, and water secretion was greater than with glucose. With equimolar (112 mmol/l) glucose + disaccharide mixtures, intraluminal glucose concentrations were similar to but total glucose absorption less than expected from experiments with the individual sugars. The results favour sequential hydrolysis-absorption whereby high concentrations of monosaccharide accumulate at the brush border and promote sugar uptake by conventional rather than 'disaccharidase-related' transport, and stimulate water secretion by local osmotic effects.

Adolescent↗
PubMed1980

Prolonged incubation period of imported P. vivax malaria in London.

Between January 1976 and July 1979, 453 cases of malaria were seen at Hillingdon Hospital. The majority of cases were Plasmodium vivax infections in Asians from the Punjab in Northern India-either new immigrants or United Kingdom resident Asians returning from holidays. Twenty-four cases were contracted in Africa or the Middle East. Figures are presented showing a considerable increase in cases during the period of study. In P. vivax infections the time interval between arrival and development of the acute illness was significantly greater for those subjects entering the United Kingdom in autumn or winter.

Humans↗
PubMed1979

Pyruvate carboxylase from a thermophilic Bacillus: some molecular characteristics.

Analysis of the native enzyme and of the subunits produced upon its denaturation shows that pyruvate carboxylase from a thermophilic Bacillus is a tetramer with a molecular weight (mean value) of 558,000 and that the four polypeptide subunits are probably identical. The three functions (carboxyl carrier, carboxylation, and carboxyl transfer) in the pyruvate carboxylation reaction must therefore reside in this quarter-molecular polypeptide. The enzyme molecule contains four atoms of zinc and four molecules of D-biotin, and in the electron microscope the disposition of its four subunits presents a rhombic appearance. Reaction of the denatured enzyme with 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB) reveals 10 sulfhydryl groups/subunit. In the native enzyme less than one of these groups reacts with DTNB. By contrast, all of these groups (11/subunit) of the native chicken liver pyruvate carboxylase are accessible to DTNB. The thermophile enzyme is also more resistant to other sulfhydryl reagents and to denaturation under certain conditions than the avian enzyme.

Animals↗