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Biomedical subjects

R West

Publications and source records attributed to R West.

At least 235 records · Page 13Linked to original sources
PubMed1986

Do older children take in more smoke from their cigarettes? Evidence from carbon monoxide levels.

Expired-air carbon monoxide (CO) concentrations were measured in 125 pupils aged 11-17 years attending a girls' comprehensive school in the South of England who had smoked at least one cigarette on the day of testing. Both number of cigarettes smoked on the day of testing and time since the last cigarette were independently related to CO concentrations. Although there was a positive correlation between age and CO, this disappeared when number of cigarettes smoked on the day of testing and time since the last cigarette were taken into account. Previous reports of increasing CO concentrations with age taking account of cigarette consumption may be due to the use of usual daily cigarette consumption rather than number on the day of testing, which is more relevant given the short half-life of CO in the blood. In this sample, no evidence was found for an increase in smoke inhalation with increasing age.

Adolescent↗
PubMed1986

Stimulation of human fetuses with sound and vibration.

Forty pregnant women between 30 and 42 weeks' gestational age were studied to examine the effects of external sound and vibration on the fetal heart rate. A significant increase in the mean duration and amplitude of the first acceleration after sound stimulus was found when these values were compared with the control values. Conversely the mean time to the first acceleration in the control period was greater than that in the stimulated period. There was a significant increase in the mean duration of fetal heart rate accelerations, the mean amplitude of fetal heart rate accelerations, and the total time spent in accelerations up to 15 minutes after the sound stimulus as compared with the control period. There was no change in the number of accelerations following the sound stimulus compared to control. These data suggest that vibratory acoustic stimuli may influence patterns of fetal heart rate during human pregnancy.

Acoustic Stimulation↗
PubMed1986

Epithelioid haemangioendothelioma. A case report.

Epithelioid haemangioendothelioma of the liver is an extremely rare tumour which has only recently been recognised. This report describes the clinical, radiological and histological findings in a case of a primary epithelioid haemangioendothelioma of the liver. The case highlights some of the difficulties in establishing the diagnosis, and in its differentiation from Budd-Chiari syndrome and veno-occlusive disease. The patient has subsequently undergone successful orthotopic hepatic transplantation.

Diagnosis, Differential↗
PubMed1986

Scanning and transmission electron microscopic observations of the acute morphological response of the mouse urinary bladder to 4-ethylsulfonylnaphthalene-1-sulfonamide.

A total of 75 BALB/cStCrlfC3H/Nctr male weanling mice were administered either 0 or 250 ppm of 4 ethylsulfonylnaphthalene-1-sulfonamide (ENS) in the diet for periods up to 14 days to evaluate the early morphological changes of the transitional epithelium of the urinary bladder with scanning (SEM) and transmission (TEM) electron microscopy. Primary TEM changes included hyperplasia of the epithelium, loosening of the intercellular junctions, autophagic vacuoles and electron dense granules in the mitochondria. Primary SEM changes included sloughing of epithelial cells, irregularity in the size and shape of the transitional epithelial cells and the presence of microvilli. Although pleomorphic microvilli were present after only three days of treatment with ENS, it appears that they are a transient observation in a series of morphological changes. The reversibility or transient nature of the pleomorphic microvilli may indicate that they are an acute toxic response and may not necessarily indicate a preneoplastic change.

Animals↗
PubMed1985

Treatment of homozygous familial hypercholesterolaemia: an informative sibship.

In a family in which both parents had the heterozygous form of familial hypercholesterolaemia four of the children had the homozygous form. The three oldest homozygous children, two of whom did not receive any treatment and in one of whom treatment did not lower the plasma cholesterol concentration, developed xanthomas in early childhood and died aged 3, 9, and 10 years. The fourth homozygous child was treated with diet and drugs from the age of 1 and at the age of 15 had no xanthomas, no clinical evidence of heart disease, and a virtually normal coronary angiogram. His plasma cholesterol concentration was reduced by about 30% but remained considerably raised. It is concluded that treatment, if started before atherosclerosis develops, can delay the onset of atheroma and coronary heart disease even though normal plasma cholesterol concentrations are not achieved.

Adolescent↗
PubMed1985

Human apolipoprotein B: identification of cDNA clones and characterization of mRNA.

Apolipoprotein B (apoB) is a major protein component of low density and very low density lipoproteins. Because of its large size and heterogeneity, molecular studies of apoB have been difficult, and its structure and regulation remain poorly understood. We now report the identification of human apoB cDNA clones by antibody screening of hepatoma libraries in the expression vector lambda gt11. Both oligo(dT) primed and random primed libraries were constructed and screened with polyclonal antibodies to intact apoB, as well as with antibodies raised against a synthetic peptide based on the limited amino acid sequence available for apoB. The identity of the clones was unambiguously established by comparisons of the cloned cDNA sequences with apoB amino acid sequences. The clones hybridize to an exceptionally large 20 kb mRNA that is present in liver and intestine but not other tissues examined, consistent with the distribution expected from protein biosynthetic studies. The properties of the mRNA have implications for the biogenesis of the multiple apoB molecular weight forms secreted by liver and intestine.

Apolipoproteins B↗
PubMed1985

Cloning and expression of apolipoprotein B, the major protein of low and very low density lipoproteins.

We report the cloning of cDNAs for rat liver apolipoprotein B (apo B) and the use of the cloned sequences to examine apo B expression at the level of mRNA in rat tissues. Fifteen putative apo B clones were identified by antibody screening of a rat liver cDNA library in the lambda gt11 expression vector. The identity of the clones was confirmed by immunological studies of the fusion protein products. All clones appear to contain sequences found only in apo B PI, the high molecular weight form of rat liver apo B. Blotting studies show that the clones hybridize to a single 20-kilobase liver mRNA species, sufficiently large to encode the entire apo B PI peptide, which is estimated to be 400 kDa in size. Apo B PI mRNA is abundant in liver and present in lower amounts in intestine but is absent in a variety of other tissues examined. This tissue distribution is consistent with that expected from studies on the in vivo synthesis of apo B. One clone, corresponding to a 240-base segment of the apo B PI mRNA, was sequenced and found to exhibit homology with a short region of rat apo E mRNA. Analysis of the secondary structure of the corresponding peptide did not show the preponderance of amphipathic alpha-helical structures characteristic of other apolipoproteins examined thus far.

Amino Acid Sequence↗
PubMed1985

Endoscopic variceal pressure measurements: response to isosorbide dinitrate.

An endoscopic pressure sensor has been evaluated in the measurement of oesophageal variceal pressure and its response to drug ingestion. The variceal pressure showed a highly significant correlation with the splenic pulp pressure (r = 0.97) in six patients with liver disease of diverse aetiology and with hepatic venous wedge pressure (r = 0.92) in eight alcoholic cirrhotic men. Intraduodenal infusion of isosorbide dinitrate in the cirrhotics produced no change in wedge pressure or endoscopic variceal pressure despite profound falls in arterial systolic pressure. Thus isosorbide dinitrate appears to be of no value in treating portal hypertension. This study establishes the endoscopic pressure sensor as a valuable tool in screening drugs in this condition.

Adult↗
PubMed1984

An evaluation of the intervention against smoking in the multiple risk factor intervention trial.

The results of the Multiple Risk Factor Intervention Trial showed no significant difference in mortality from coronary heart disease between intervention and control groups despite an apparent success of the intervention against cigarette smoking. A reanalysis of the published data indicates that the effectiveness of the smoking intervention may have been overestimated. The researchers counted those who smoked pipes or cigars at screen as nonsmokers and attempted to classify cigarette smokers who switched to pipes or cigars during the trial as successes whether or not they continued to inhale the smoke. It is unreasonable to assume a priori that inhaling pipe or cigar smoke is less dangerous than cigarette smoke. Moreover, attempting to include pipe and cigar smokers, who may have been inhaling smoke, among the successes makes biochemical validation of claims of abstinence overly lenient. When levels of serum thiocyanate are used to obtain an objective index of smoking reduction, it appears that the effect of intervention was considerably smaller than has been reported, and failed to reach design goals over the first 4 years. This could help to explain the disappointing mortality results.

Carbon Monoxide↗
PubMed1984

Use of lacZ fusions to delimit regulatory elements of the inducible divergent GAL1-GAL10 promoter in Saccharomyces cerevisiae.

We present the DNA sequence of a 914-base pair fragment from Saccharomyces cerevisiae that contains the GAL1-GAL10 divergent promoter, 140 base pairs of GAL10 coding sequence, and 87 base pairs of GAL1 coding sequence. From this fragment, we constructed four pairs of GAL1-lacZ and GAL10-lacZ fusions on various types of yeast plasmid vectors. On each type of vector, the fused genes were induced by galactose and repressed by glucose. The response of a GAL1-lacZ fusion to gal4 and gal80 regulatory mutations was similar to the response of intact chromosomal GAL1 and GAL10 genes. A set of deletions that removed various portions of the GAL10 regulatory sequences from a GAL10-CYC1-lacZ fusion was constructed in vitro. These deletions defined a relatively guanine-cytosine-rich region of 45 base pairs that contained sequences necessary for full-strength galactose induction and an adjacent guanine-cytosine rich 55 base pairs that contained sequences sufficient for weak induction.

Alleles↗
PubMed1983

Increased blood-brain transport of tryptophan after portacaval anastomoses in germ-free rats.

Portal-systemic shunting in rats results in altered plasma concentrations of the large neutral amino acids (NAA), and increased blood-brain barrier NAA transport. Bacterial ammonia production in the bowel, especially the colon, is thought to play a major role in the etiology of portal-systemic encephalopathy (PSE). In order to isolate the role of bacteria in PSE, plasma and brain amino acids and ammonia (NH3) were studied in germ-free (GF) rats with portacaval shunts (PCS). Germ-free rats underwent end-to-side portacaval shunt or sham operation under germ-free conditions and were kept in a germ-free isolator under careful bacteriologic control. Similar operations were carried out on conventional animals. Two weeks post-operatively blood-brain transport of the neutral amino acid tryptophan was studied and the animals sacrificed. Plasma NH3 rose after PCS both in GF and in conventional rats. In germ-free and conventional rats with PCS, there was a significant elevation in plasma of the aromatic amino acids and decreased concentrations of the branched-chain amino acids. In the brain, both groups had elevated aromatic amino acids, while the branched-chain amino acids remained normal. The blood-brain transport of tryptophan was elevated in portacaval shunted rats, whether germ-free or conventional. These studies suggest the elevated plasma levels of ammonia and disturbances in plasma and brain amino acids seen after portacaval shunt are not dependent on the presence of gut bacteria.

Amino Acids↗