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Biomedical subjects

J Lewis

Publications and source records attributed to J Lewis.

At least 325 records · Page 18Linked to original sources
PubMed1988

Trace nutrients. 5. Minerals and vitamins in the British household food supply.

1. The amounts of magnesium, copper, zinc, phosphorus, manganese, potassium, vitamin B6, vitamin B12, folate, pantothenic acid, biotin, vitamin E and dietary fibre in the British household diet were calculated by applying appropriate values from recent analytical studies to the amounts of foods recorded in the National Food Survey during 1986. 2. National average intakes were (mg/person per d): Mg 247, Cu 1.25, Zn 9.0, P 1249, Mn 3.43, K 2694, vitamin B6 1.73, vitamin B12 6.33 micrograms, folate 230 micrograms, pantothenic acid 6.07, biotin 35 micrograms, vitamin E 8.4. Regional and income-group differences were estimated, and found to be small. Additional contributions from alcoholic drinks and confectionery were also determined. 3. Dietary fibre was estimated both as unavailable carbohydrate and as non-starch polysaccharide. The national average intakes were 21.8 and 12.9 g/d respectively. 4. Intakes were compared with Canadian (Department of National Health and Welfare, 1983) and American (National Research Council, 1980) recommended dietary allowances (RDAs). With the exception of biotin, the Canadian RDAs were met by the household diet but the much higher American RDAs were only met for vitamin B12 and pantothenic acid.

Food Analysis↗
PubMed1988

Radionuclide measurements of diastolic function for assessing early left ventricular abnormalities in the hypertensive patient.

Three measurements of diastolic filling were compared in 29 patients with essential hypertension and 27 age matched normotensive controls. Systolic function was normal in all but one of the patients. The mean (1SD) first one third filling fraction (a measurement of early diastolic filling) was significantly lower in the hypertensive groups (0.27 (0.24] than in the control group (0.45 (0.16)). The hypertensive group was subdivided into those with electrocardiographic abnormalities and those without. In the subgroup with a normal electrocardiogram the mean (1SD) first one third filling fraction measurement (0.28 (0.16)) was significantly lower than in the control group. In the subgroup with an abnormal electrocardiogram, the first one third filling fraction was even lower (0.24 (0.9)). In addition, the time to peak filling rate (213 (56) ms) was significantly longer in the subgroup with the abnormal electrocardiogram than in the control group (164 (45) ms). However, the interobserver reproducibility of the time to peak filling measurement was poor. The peak filling rate was low in the subgroup with an abnormal electrocardiogram, but not significantly different from the normal controls. The discriminatory value of the three diastolic measurements did not improve with exercise. These results showed an early diastolic filling abnormality in essential hypertension that did not appear to be caused by disease of the large coronary vessels as it was present in patients with normal wall motion and a normal exercise electrocardiogram. The occurrence of diastolic abnormalities when systolic function is still normal may mark an early stage in the development of hypertensive heart failure, at a time when the process is still potentially reversible.

Adult↗
PubMed1988

Characterization of antisera distinguishing carbohydrate structures in the beta-carboxyl-terminal region of human chorionic gonadotropin.

The beta-COOH-terminal peptide region (beta CTP) of hCG is an important immunochemical domain that is specific to hCG but absent from homologous hLH. Three types of polyclonal antibodies can be elicited to the beta CTP portion of hCG. The first and most common recognizes the beta CTP amino acid sequence independent of its carbohydrate content (carbohydrate-oblivious). It can be elicited against synthetic beta CTP as well as against native or asialo beta CTP. The second type binds best to desialylated beta CTP, (galactose-requiring). The third type binds well only to sialylated beta CTP (sialic acid-requiring). All three types of antisera recognize the sialylated beta CTP as equivalent to the whole hormone on a molar basis, indicating that this peptide region of the whole hormone is neither sequestered nor conformationally altered. We have characterized the epitopes for the sialic acid-requiring and galactose-requiring beta CTP antisera. Both require elements of the primary amino acid sequence of beta hCG as well as specific elements of the carbohydrate side-chains and, therefore, are not directed solely to either peptide or carbohydrate determinants. The galactose-requiring beta CTP antiserum was generated to an ovalbumin conjugate of a desialylated form of beta CTP, beta 123-145. It binds desialylated forms 1000 times better than it binds native hCG, and binds neither synthetic beta CTP nor asialo-agalacto beta 123-141. The antiserum requires residues 123-141 and a portion of an O-serine-linked oligosaccharide chain. Its binding requirements are, thus, very different from those of the carbohydrate-oblivious beta CTP antiserum, which requires the last two residues of the hCG beta polypeptide chain and is not sensitive to the presence or absence of carbohydrate. The sialic acid-requiring beta CTP antiserum, which was generated to sialylated beta 123-145-thyroglobulin conjugate, binds well to sialylated beta CTP, but poorly to asialo beta CTP and not at all to the carbohydrate-free synthetic peptide. This antiserum requires the entire beta 123-145 sequence as well as sialic acid-terminated oligosaccharide side-chains. Since the sialylated peptide beta 115-141 binds poorly to it, this antiserum resembles the carbohydrate-oblivious anti-beta CTP; both require the COOH-terminal amino acids of hCG beta. However, the former requires intact O-linked carbohydrate moieties for binding. These antisera can be used to assess the primary protein and carbohydrate structures of beta CTP at low concentrations in urine.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1987

Heat shock induces peroxidase activity in Neurospora crassa and confers tolerance toward oxidative stress.

Heat shock treatment of 14-h-old Neurospora crassa mycelium, for 1 h at 48 degrees C, led to the induction of high levels of peroxidase (EC. 1.11.1.7) activity. No significant change was observed in the superoxide dismutase content. Colonies formed by plating conidial suspensions on sorbose-medium also exhibited high peroxidase activity following exposure to hyperthermia and were found to be resistant to normally toxic doses of H2O2. Thus one of the heat shock proteins of N. crassa has the function of protection against oxidative stress.

Hot Temperature↗
PubMed1987

Monoaminergic correlates of kindling.

High-performance liquid chromatography with electrochemical detection was used to measure the regional concentrations of monoamines and metabolites in the brains of rats killed 2 or 4 weeks after kindling of generalized seizures with amygdaloid stimulation. Each kindled rat was compared to a yoked control that received brief trains of non-convulsive low-frequency stimulation of the amygdala. Two weeks after kindling we found a significant depletion of noradrenaline (NA) in the ipsilateral frontal cortex, a significant depletion of serotonin (5-HT) in the stimulated amygdala and contralateral hypothalamus, and no significant changes in concentration of dopamine (DA). Four weeks after kindling we found significant depletions of NA in the stimulated amygdala and ipsilateral hypothalamus, a significant depletion of 5-HT in the ipsilateral hippocampus, and no significant changes in DA. These findings generally fail to replicate previous reports of monoaminergic correlates of kindling. Furthermore, the alterations in monoamines produced by kindling do not fall into a simple and readily interpretable pattern.

Animals↗
PubMed1987

Comparison of three treatment strategies for esophageal cancer within a single institution.

Fifty-seven patients with esophageal cancer were treated with curative intent between January 1979 and June 1985. Seventeen were treated with radical radiation therapy alone (TD 4000-6500 cGy in 200-250 cGy fractions). Twenty-five were treated using radiation therapy (3000 cGy in 200 cGy fractions, day 1-19, and 2600-3000 cGy in 200 cGy fractions, day 50-68) and concomitant chemotherapy (5-FU and Cis-platinum). Fifteen were treated preoperatively by radiation therapy (3000 cGy at 200 cGy fractions) and concomitant chemotherapy (5-FU and Cis-platinum) followed by esophagectomy in 2-3 weeks. Chi square tests showed no significant baseline differences between the patients in the three different treatment groups with respect to A.J.C. stage, T status, location of tumor or histology. Median survival and 2-year survival for the three treatment groups were RT alone: 5 months and 0%, RT and chemotherapy: 12 months and 37%, RT, chemotherapy and surgery 13 months and 38%. A Cox multivariate analysis revealed significant predictor variables for increased survival were treatment strategy, RT dose delivered and T status. Increased local control was seen with either multimodality approach compared to radiation therapy alone. Our data suggests that a multimodality approach is superior as a curative treatment strategy, compared to RT alone, in esophageal cancer. In our series no significant differences were seen with respect to treatment outcome between the two multimodality approaches used.

Adenocarcinoma↗
PubMed1987

Metabolic response to total hip arthroplasty under hypobaric subarachnoid or general anaesthesia.

Whole blood glucose concentration was estimated in 93 patients undergoing total hip arthroplasty under either subarachnoid or general anaesthesia. In 77, plasma cortisol concentration was also estimated before and after surgery. There were no preoperative differences between the two groups. Blood glucose concentration increased slightly following induction in both groups, but with spinal anaesthesia it decreased again, whereas with general anaesthesia it continued to increase (P less than 0.0001). Plasma cortisol concentration with spinal anaesthesia was 291 (SD 145) nmol litre-1 before, and 279 (253) nmol litre-1 30 min after operation. With general anaesthesia there was a three-fold increase from 301 (159) nmol litre-1 (preoperative) to 987 (474) nmol litre-1 30 min after operation (P less than 0.0001). Low spinal anaesthesia with a predominantly unilateral block appears sufficient to suppress the neuroendocrine response to hip surgery.

Aged↗
PubMed1987

Epithelial ovarian cancer and coffee drinking.

A recent report from a case-control study in Greece suggested that coffee consumption is related to an increase in the risk of ovarian cancer. This hypothesis was examined in a hospital-based case-control study in the US. Information on coffee drinking and other factors was obtained from 290 incident cases of epithelial ovarian cancer and compared with that of 580 controls with non-malignant conditions of acute onset and 476 controls with cancer of other sites. Adjustment was made for the potential confounding effects of several factors, including the major known risk factors for ovarian cancer. The estimated relative risk for drinking five or more cups of coffee per day, relative to none, was 1.1 (95% confidence interval, 0.6-2.0) using the controls with non-malignant conditions and 1.0 (0.5-1.8) using the controls with cancer. The estimates for drinking less than five cups per day were greater than 1.0, but this could have been due to chance. The consumption of decaffeinated coffee and tea also appeared to have no influence on risk. The evidence from this study suggests that, if coffee drinking increases the risk of ovarian cancer, the effect is small.

Adult↗
PubMed1987

Clinical relevance of therapeutic drug level estimation with respect to clonazepam and carbamazepine: preliminary report.

This paper compares the results of plasma drug level estimations for 30 patients receiving clonazepam and 39 patients taking carbamazepine (assessing total and free carbamazepine concentrations together with carbamazepine epoxide levels) with the clinical features of seizure control. Owing to the small numbers of seizure-free patients, the power of the study was insufficient to justify absolute conclusions being drawn. However there appeared to be a trend which suggested that drug level estimations in both situations had virtually no clinical relevance. This causes one to question the growing reliance on plasma drug level estimation in the treatment of epilepsy and, because of the low power of the study, demands extension of the work to confirm its significance. This type of research in epilepsy, based exclusively on a secondary and tertiary referral source, has inherent difficulty in that a conspicuously low number of well controlled patients is included. Acknowledgement of this fact should lead one to appraise critically other papers giving dogmatic statements regarding therapeutic ranges of anticonvulsant plasma levels.

Adolescent↗