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Biomedical subjects

B Norton

Publications and source records attributed to B Norton.

At least 19 recordsLinked to original sources
PubMed2001

Central venous catheterization and fatal cardiac tamponade.

Cardiac tamponade is a poorly recognized complication of central venous catheterization associated with a high mortality. We present a case of fatal cardiac tamponade after intra- pericardial infusion of total parenteral nutrition in a patient who had two central venous catheters. We suggest that catheter tip position should always be confirmed before use of a catheter. Tamponade should be suspected in a patient who deteriorates when a central venous catheter is used and resuscitation via the catheter should be avoided.

Adult↗
PubMed1999

Weight loss has an independent beneficial effect on symptoms of gastro-oesophageal reflux in patients who are overweight.

BACKGROUND: Weight loss is commonly recommended as part of first-line management of gastrooesophageal reflux disease (GORD) despite the paucity of published clinical trials. The aim of this study was to prospectively assess the independent effect of weight loss on reflux symptoms in overweight individuals with either normal endoscopic findings or grade-I oesophagitis. METHODS: Thirty-four patients were recruited on the basis of a body mass index (BMI) of greater than 23 and symptoms of GORD for at least 6 months. All patients were advised to lose weight. Symptoms of gastro-oesophageal reflux (GOR) were scored, using a modified DeMeester questionnaire at 0, 6, and 26 weeks. Patients who were unable to stop taking all medication for control of symptoms were excluded from the study. Changes in weight and symptom score were analysed by using a paired t test. Correlation between change in weight and symptom score was assessed with the Pearson correlation test. RESULTS: Thirty-four patients were studied (18 men and 16 women) with a mean age of 65 years (range, 24-70 years). The mean weight at recruitment was 83.4 kg (standard deviation (s), 4.5 kg; BMI, 23.5 kg/m2 (s, 2.3 kg/m2). Twenty-seven patients (80% of the total) lost weight with a mean of 4.0 kg (P < 0.01) and improved by a mean reduction of 75% from the initial symptom score (P < 0.001). In nine patients the symptoms disappeared completely. Three patients gained weight and had a deterioration of their symptoms, whereas four patients gained weight but still improved their symptom score. There was a significant direct correlation between weight loss and symptom score (R = 0.548, P < 0.001). CONCLUSIONS: This study has shown a significant association between weight loss and improvement in symptoms of GOR. Patients who are overweight should be encouraged to lose weight as part of the first-line management.

Aged↗
PubMed1999

Intra-hepatic false aneurysm: a rare complication of ERCP.

We report a rare case in which an intra-hepatic false aneurysm formed following endoscopic retrograde cholangiopancreatography and presented with life-threatening gastrointestinal bleeding. The aetiology, investigation and management of intra-hepatic false aneurysm is discussed.

Aged↗
PubMed1996

A randomised prospective comparison of percutaneous endoscopic gastrostomy and nasogastric tube feeding after acute dysphagic stroke.

OBJECTIVE: To compare percutaneous endoscopic gastrostomy and nasogastric tube feeding after acute dysphagic stroke. DESIGN: Randomised prospective study of inpatients with acute stroke requiring enteral nutrition. SETTING: One university hospital (Nottingham) and one district general hospital (Derby). SUBJECTS: 30 patients with persisting dysphagia at 14 days after acute stroke: 16 patients were randomised to gastrostomy tube feeding and 14 to nasogastric tube feeding. MAIN OUTCOME MEASURES: Six week mortality; amount of feed administered; change in nutritional state; treatment failure; and length of hospital stay. RESULTS: Mortality at 6 weeks was significantly lower in the gastrostomy group with two deaths (12%) compared with eight deaths (57%) in the nasogastric group (P < 0.05). All gastrostomy fed patients (16) received the total prescribed feed whereas 10/14 (71%) of nasogastric patients lost at least one day's feed. Nasogastric patients received a significantly (P < 0.001) smaller proportion of their prescribed feed (78%; 95% confidence interval 63% to 94%) compared with the gastrostomy group (100%). Patients fed via a gastrostomy tube showed greater improvement in nutritional state, according to several different criteria at six weeks compared with the nasogastric group. In the gastrostomy group the mean albumin concentration increased from 27.1 g/l (24.5 g/l to 29.7 g/l) to 30.1 g/l (28.3 g/l to 31.9 g/l). In contrast, among the nasogastric group there was a reduction from 31.4 g/l (28.6 g/l to 34.2 g/l) to 22.3 g/l (20.7 g/l to 23.9 g/l) (P < 0.003). In addition, there were fewer treatment failures in the gastrostomy group (0/16 versus 3/14). Six patients from the gastrostomy group were discharged from hospital within six weeks of the procedure compared with none from the nasogastric group (P < 0.05). CONCLUSION: This study indicates that early gastrostomy tube feeding is greatly superior to nasogastric tube feeding and should be the nutritional treatment of choice for patients with acute dysphagic stroke.

Acute Disease↗
PubMed1994

TGF-beta 1 and 25-hydroxycholesterol stimulate osteoblast-like vascular cells to calcify.

Previous studies in our laboratory demonstrated messenger RNA for bone morphogenetic protein-2a in human calcified plaque, suggesting that arterial calcification is a regulated process, similar to osteogenesis. To further test this hypothesis, we have isolated and cloned a subpopulation of cells from bovine aortic media that show osteoblastic potential. These novel cells are primarily distinguished from smooth muscle cells by expression of a surface marker preliminarily identified as a modified form of the ganglioside sialyl-lactosylceramide (GM3). Osteoblastic potential was indicated by high levels of alkaline phosphatase and collagen I, expression of osteopontin and osteonectin (SPARC), and production of bone-specific osteocalcin and hydroxyapatite. Cultures of these cells were stimulated to form increased numbers of calcium-mineral-producing nodules by the oxysterol 25-hydroxycholesterol as well as by transforming growth factor-beta 1, both known to be present in atherosclerotic lesions. The stimulation of calcifying vascular cells in the artery wall by these two factors suggests a possible mechanism for the colocalization of calcification with atherosclerosis in vivo.

Alkaline Phosphatase↗
PubMed1993

Pharmacological studies of K+ loss from ischaemic myocardium in vitro: roles of ATP-dependent K+ channels and lactate-coupled efflux.

Perfused guinea-pig hearts were rendered ischaemic by 95% reductions in coronary flow. K+ and lactate release over the first 6 min of ischaemia were reduced by glibenclamide (described as a K+ATP channel blocker), 2-deoxyglucose (inhibitor of lactate synthesis) and alpha-cyano-4-hydroxycinnamic acid (inhibitor of lactate transport). Glibenclamide did not selectively reduce K+ loss without affecting lactate release, as would be expected for a selective K+ATP channel blocker. During a single 30 min period of ischaemia, a secondary release of K+ was observed corresponding to the onset of ventricular fibrillation, with no associated increase in lactate efflux, which appeared sensitive to glibenclamide. In conclusion, glibenclamide failed to reduce K+ loss in early ischaemia without reducing lactate release as would be expected for a selective K+ATP channel blocker. Caution should be exercised when using glibenclamide as a specific blocker of K+ATP channels in the absence of measurements of metabolic parameters.

Adenosine Triphosphate↗
PubMed1993

New technique to measure mucosal metabolism and its use to map substrate utilization in the healthy human large bowel.

A new method of assessing substrate utilization in gastrointestinal mucosal specimens is described. Small human endoscopic biopsy specimens with wet weights ranging between 1.4 and 12.2 mg were used to quantify the oxidation of three metabolic substrates, glucose, glutamine and butyrate, through to carbon dioxide over a 2-h period. The technique proved to be reproducible and capable of distinguishing variations in mucosal metabolism between individuals (P < 0.0001 for each substrate). Results were similar to those obtained previously using human and rat colonocytes. To characterize the metabolism of the healthy large bowel, specimens were obtained from five regions in 15 patients who had a normal colonoscopic examination. The results show that butyrate is the preferred fuel source of large bowel mucosa, followed by glutamine, then glucose (P < 0.01). There was no significant regional variation in utilization of the three substrates between the five regions; with respect to glutamine, this is contrary to previous findings.

Adult↗
PubMed1993

Evidence for involvement of a second genetic locus on chromosome 11q in porphyrin metabolism.

Chester porphyria is a distinct type of acute porphyria, which shows a biochemical overlap with acute intermittent and variegate porphyrias and has a dual enzyme deficiency of porphobilinogen deaminase (PBGD) and protoporphyrinogen oxidase. Linkage analysis in an extensive family with Chester porphyria was undertaken using multiple polymorphic markers. A maximum two point Lod score of 5.25 at 0.07 recombination (confidence interval 0.01 to 0.14) was observed with D11S351, which has been localised to 11q23.1. Multipoint linkage analysis confirmed the two point results and gave a maximum Lod score of 7.33 at a distance less than 1 cM proximal to D11S351. PBGD also maps to 11q but four recombinants could be identified from ten informative meioses in this family using a PBGD DNA polymorphism. Thus, a separate locus on 11q appears to be the basis of Chester porphyria.

Chromosome Mapping↗
PubMed1987

The effect of maternal psychotic illness on a child.

We report the case of an 11-year-old girl who had been living with only her mother, a woman with chronic schizophrenia. The girl had been caught shoplifting with her mother, and had a long history of non-attendance at school. The case emphasises that adult psychiatrists should always consider the impact of chronic parental psychiatric disorder on children, particularly in one-parent families.

Child↗
PubMed1984

Regiospecific transfer of tritium into 3H2O from labeled estrogens by mushroom tyrosinase.

The specificity of mushroom tyrosinase in displacing 3H from estradiol and catechol estrogens labeled at C-1, C-2, C-4 or C-6,7 was investigated under various conditions. [2-3H]E2 Yielded significant amounts of 3H2O, in the presence of NADH, and the rate of 3H loss from the steroid paralleled that of the radioactivity remaining in the aqueous fraction after extraction with organic solvents. NADH had little effect on the release of 3H from [1-3H]E2 or [4-3H]E2 but glutathione was highly active in this respect, with considerable differences being observed between lyophilizable 3H2O and yields of water-soluble products. It is proposed that 3H losses from C-2 of estradiol reflects oxidative displacement of this isotope by tyrosinase while the loss observed from C-1 and C-4 is the result of non-enzymatic conjugation with glutathione after the formation of the catechol estrogen. The difference between lyophilizable 3H2O and the yield of water-soluble products obtained with [1-3H]E2 and [4-3H]E2 provided a measure of the relative amount of conjugation occurring at C-1 and C-4. These findings were confirmed by double label experiments with 3H- and 14C-labeled estrogens and the isolation of the glutathionyl derivatives. The catechol estrogens did not serve as substrates for further hydroxylation by the enzyme even when C-2 was available for this reaction. These experiments give further information about the specificity of tyrosinase in its reaction with aromatic steroids and provide a simple and rapid method for confirming the distribution of 3H at C-2 or C-4 of estradiol.

Basidiomycota↗
PubMed1984

Mortality of a lithium-treated population.

In South-East Scotland, 791 subjects treated with lithium for more than two months during 1967-76 were traced, using public and health service records; 751 were traced alive, 33 had died, and seven remained untraced. The standardised mortality rate was 2.83, and excess mortality was attributable to suicide (increased 36-times) and cardiovascular disease (increased 2.15-times); deaths from nephropathy, cancer or leukaemia were not increased. Comparison of the 33 deaths and 33 matched patients, selected from the 751 survivors, showed that patients dying on lithium were similar in most respects to survivors, but when first starting lithium, they had more signs of physical disease.

Aged↗
PubMed1983

6. Steroid metabolism in neuroendocrine structures. Specific and nonspecific components in the oxidative metabolism of estradiol by the male rat brain in vitro.

The oxidative transformation of estradiol at the C-2 and C-4 positions in the male rat brain was studied by the transfer of 3H into water from [2-3H]- and [4-3H]-estradiol. The nonenzymatic transformation at either site was linear with substrate concentration. The addition of pyridine nucleotide cofactors had no effect on the transformation at the C-4 site. The C-2 reaction was greatly enhanced by NADPH or NADH and exhibited the greatest velocity in the microsomal formation in the presence of NADH. The C-2 reaction exhibited saturation with respect to substrate and NADH with apparent KM of 1.82 microM and 0.34 mM respectively and Vmax of 81.3-76.3 pmol/mg protein/60 min. The reaction at C-4 failed to exhibit substrate saturation up to 30 microM. These data indicate that male rat brain estrogen hydroxylase is specific for the C-2 position, is NADH dependent and thus different from the corresponding liver enzyme. The reaction at C-4 in the brain tissues fails to exhibit enzymatic characteristics and the formation of 4-hydroxyestrogens in that tissue may be artifactual.

Animals↗
PubMed1981

[Not Available].

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Genetics↗