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Biomedical subjects

J D Maxwell

Publications and source records attributed to J D Maxwell.

At least 91 records · Page 5Linked to original sources
PubMed1986

Alcohol and dilated cardiomyopathy.

Alcohol has been considered a cardiotoxin for over a century, but the pathogenesis and natural history of alcohol-related heart disease remains obscure. The diagnosis still rests on the coincidence of alcoholism and a dilated hypocontractile heart in the absence of any other cause of dilated cardiomyopathy. Advances have been made in our understanding of the effects of acute and chronic alcohol administration both at a haemodynamic and cellular level, and recent studies have indicated that preclinical changes in LV dimensions and function are common in alcoholics. It is not known whether clinical cardiomyopathy, which develops in only 1-2% of heavy drinkers, occurs because of genetic predisposition, or the presence of synergistic cardiovascular risk factors. Abstinence remains the mainstay of treatment, but the prognosis is poor after development of frank heart failure.

Actins↗
PubMed1985

Vitamin D deficiency in adult British Hindu Asians: a family disorder.

The vitamin D state of 60 apparently healthy adult Hindu Asian couples living in Britain was studied on a community basis. Twenty six (22%) of the Asian subjects had pronounced vitamin D deficiency, defined as 25-hydroxycholecalciferol concentrations below 10 nmol/l (4 ng/ml), while none of the white controls had such low concentrations. Asian men and women were equally affected, and plasma concentrations were similar in husbands and wives. Vitamin supplements were being taken by only 31 (26%) subjects, most of whom were women. It is suggested that the spouses of patients with osteomalacia should be screened for vitamin D deficiency.

Adult↗
PubMed1985

Preclinical left ventricular abnormalities in alcoholics are independent of nutritional status, cirrhosis, and cigarette smoking.

M mode echo recordings of the left ventricle (LV) were performed in 33 patients with alcoholic liver disease, 26 patients with various non-alcoholic liver diseases, and in 18 non-alcoholic controls. Groups were well matched for age and overall nutritional status (as assessed by anthropometry) and none of the subjects studied had cardiorespiratory symptoms. Alcoholics had significantly increased LV free wall thickness and LV cavity dimension at end diastole (EDD). Multiple regression analysis of the data identified alcohol abuse as the most important variable affecting EDD, and this relation could not be explained by differences in age, sex, overall nutrition, cigarette smoking, thiamine status (total blood thiamine and thiamine pyrophosphate concentration), presence of liver disease, or severity of liver disease (cirrhotic vs non-cirrhotic). The increase in LV free wall thickness was not significantly related to alcohol abuse. These results suggest that chronic alcohol abuse is an important independent risk factor for cardiac dilatation, and that increase in EDD may be an early marker of alcoholic cardiomyopathy.

Adult↗
PubMed1985

Nutritional assessment in patients with chronic gastrointestinal symptoms: comparison of functional and organic disorders.

We assessed the nutritional status of 119 patients with chronic gastrointestinal symptoms due to organic disorders (inflammatory bowel disease, IBD; peptic ulcer, PU; malabsorption syndrome, M; and malignant gastrointestinal tumours, T), by standard anthropometry and marker proteins (albumin; retinol-binding protein, RBP; and thyroxine-binding prealbumin, TBPA). We also studied 31 patients with irritable bowel syndrome (IBS) and 75 age-matched healthy controls (C). Compared with healthy controls, patients with organic bowel disease had significant abnormality of two or more anthropometric measurements (P less than 0.05). Plasma albumin was reduced in patients with IBD, M and T (P less than 0.001), but RBP and TBPA measurements were lower in all patient categories (P less than 0.01) including IBS. Stepwise discriminant analysis of the patient data alone, using three to six parameters, correctly separated 65 per cent PU patients, 66 per cent IBD and M, 72 per cent IBS and 88 per cent patients with T from other disease categories. We conclude that patients with chronic gastrointestinal symptoms often have some nutritional disturbances and that simple anthropometric and protein measurements might help us to distinguish patients with functional bowel disease from those with organic bowel disease.

Adolescent↗
PubMed1984

Blood thiamine and thiamine phosphate ester concentrations in alcoholic and non-alcoholic liver diseases.

Thiamine state was investigated in patients with alcoholic liver disease, patients with various non-alcoholic liver diseases, and controls using a direct technique (thiochrome assay) to measure thiamine, thiamine monophospate, and the active coenzyme thiamine pyrophosphate in whole blood after isolating the fractions by ion exchange chromatography. Overall nutrition was similar in all groups as assessed by anthropometry, and no patient had clinical evidence of thiamine deficiency. There was no significant difference among the groups in mean concentration of any form of thiamine. The scatter was much greater in patients with alcoholic liver disease but only 8.7% had biochemical thiamine deficiency (defined as a blood concentration of the active coenzyme greater than 2 SD below the mean control value). An unexpected finding was of abnormally high total thiamine concentrations (greater than 2 SD above the mean control value) in 17.4% of patients with alcoholic liver disease, the highest concentrations being found in two patients with severe alcoholic hepatitis and cirrhosis. The ratio of phosphorylated to unphosphorylated thiamine was calculated as an index of phosphorylation and, although the mean did not differ significantly among the groups, the range was greatest in alcoholic liver disease. The lowest ratios occurred in the two patients with severe alcoholic hepatitis, but neither had evidence of thiamine pyrophosphate deficiency. Contrary to studies using indirect assay techniques, these results suggest that thiamine deficiency is unusual in well nourished patients with alcoholic liver disease. The new finding of unexpectedly high thiamine concentrations in some patients may be due to abnormalities of hepatic storage or release in liver disease, particularly in severe alcoholic hepatitis. There was no convincing evidence of impaired thiamine phosphorylation in any patients with liver disease. Conclusions from studies using indirect assays on the prevalence and mechanisms of thiamine deficiency in liver diseases may not be valid.

Adult↗
PubMed1983

Subclinical protein malnutrition in irritable bowel syndrome: assessment by retinol-binding protein (RBP) and thyroxine-binding pre-albumin (TBPA).

We have assessed the nutritional status of 31 patients with irritable bowel syndrome (IBS) and 75 control subjects by anthropometry (height, weight, mid-arm circumference, biceps, triceps and subscapular skinfolds) and three plasma proteins: albumin, retinol-binding protein (RBP), and thyroxine-binding pre-albumin (TBPA). There was no significant difference between the patients and controls for any of the anthropometric measurements, but mean (+/- s.d.) plasma concentrations of RBP and TBPA were significantly lower in patients with IBS, 7.21 +/- 2.77 mg/dl (P less than 0.01); and 26.57 +/- 7.33 mg/dl, (P less than 0.001) respectively than in the control group, 8.85 +/- 2.56 mg/dl and 32.71 +/- 6.30 mg/dl. We conclude that patients with IBS may have subclinical protein deficiency in the absence of demonstrable organic bowel disease.

Adult↗
PubMed1982

Biliary excretion of amoxycillin and ceftriaxone after intravenous administration in man.

1 Plasma and biliary concentrations of amoxycillin and ceftriaxone were measured after bolus intravenous administration (500 mg) in four subjects with normal hepato-biliary and renal function. 2 The mean plasma elimination half-life for ceftriaxone (t 1/2 = 330 +/- 30 min) was considerably longer than that for amoxycillin (t 1/2 = 60 +/- 9 min). 3 The biliary concentration of ceftriaxone was above plasma concentration of the drug throughout the study period, whereas amoxycillin concentration in the bile was lower than that in plasma. 4 Both plasma and biliary concentrations of ceftriaxone were substantially higher than previously determined minimum inhibitory concentration (MIC) values for E. coli (and several other common biliary tract pathogens) for over 6 h following drug administration. Amoxycillin concentration in plasma fell below MIC by 2 h, and did not reach inhibitory concentrations in bile.

Adult↗
PubMed1982

Intestinal bypass in the rat: a model for growth failure, liver disease, and jejunal bacterial overgrowth in marasmus and kwashiorkor.

The role of small intestinal bacterial colonisation on growth, liver function, and survival was examined in young rats, by comparing the effects of 90% small intestinal resection (resulting in nutritional disturbance from loss of absorptive surface) with equivalent small intestinal bypass (where the nutritional disturbance is accompanied by bacterial overgrowth in the long bypassed segment of jejunoileum). Weight loss in bypass rats was double that seen in resected animals. This was not due to enhanced malabsorption, but was the result of reduced food intake. In addition, bypass rats developed hepatocellular dysfunction, the early onset of hypoproteinaemia (occasionally accompanied by ascites), and had high mortality. Adverse effects were due to bacterial overgrowth in the long excluded segment of small bowel, as they were modified by antibacterial drugs, and were not seen in rats with nutritional disturbance (resection) alone, which adapted well and had negligible postoperative mortality. Persistent bacterial overgrowth in the small intestine can adversely affect the host's appetite, growth, liver function, and survival. These abnormalities, which developed shortly after intestinal bypass in the rat, are reminiscent of marasmus and kwashiorkor, and suggest that bacterial overgrowth, rather than dietary deficiency, may be primarily responsible for the development of infant "malnutrition" in the developing world.

Animals↗
PubMed1982

Role of anaerobic bacteria in weight loss and reduced food intake after jejuno-ileal bypass in the rat.

The mechanism of weight loss after small intestinal bypass was studied in Wistar rats. Weight loss after 90 per cent bypass was twice that after equivalent small-bowel resection. This was not due to differences in absorption, as faecal fat and energy excretion were equally increased after both procedures. However, when resected rats were pair fed with bypassed animals, their weight curves were identical, suggesting that diminished food intake was responsible for the increased weight loss after bypass. Anaerobic organisms were rarely found in normal small bowel but were present in high concentrations in the bypassed segment. Metronidazole administration significantly reduced weight loss after bypass, but not after resection. Cephalexin had no effect. These results suggest that approximately half the weight loss occurring after bypass is due to shortening of small bowel. The remainder can be accounted for by reduced food intake as a result of anaerobic overgrowth of the long excluded segment of bowel.

Anaerobiosis↗
PubMed1982

Experimental evaluation of the effect of intestinal reflux on weight loss after jejunoileal bypass.

The effect on weight loss of reflux of intestinal contents into the bypassed segment of jejunoileum after 90 per cent jejunoileal bypass was investigated in Wistar rats. No difference in weight curves was observed in rats undergoing (a) standard (end to side) jejunoileal bypass, (b) an anti-reflux procedure (end to end bypass with anastomosis of the bypassed segment to sigmoid colon), (c) bypass with separation of the bypassed segment from functioning gut and formation of an ileostomy. Faecal energy and lipid excretion was identical after end to side, and end to end jejunoileal bypass, and no different from that in rats with equivalent small bowel resection. Weight loss and malabsorption after jejunoileal bypass are unaffected by reflux of intestinal contents into the excluded gut. These experimental studies suggest that modifications of the standard jejunoileal bypass operation designed to prevent reflux of intestinal contents are unnecessary.

Animals↗
PubMed1981

Comparison of simple screening tests for fat malabsorption.

Three tests were evaluated as screening procedures for fat malabsorption--namely, measurement of serum optical density, serum triglyceride concentration, and 14CO2 breath excretion after the administration of a 60 g fat meal containing 10 muCi glycerol tri[1-14C]oleate. The results of these tests were compared with fat excreted in a three-day faecal collection after adjustment for completeness of collection as assessed by using non-absorbable radio-opaque markers. Fifty-two patients with various symptoms and eight normal subjects were studied. The maximum increase in serum optical density or triglyceride concentration above the fasting value discriminated poorly between subjects with normal and increased adjusted faecal fat excretion. In contrast, seven- or eight-hour cumulative 14CO2 breath excretion provided good discrimination with only four (7%) false-positive and no false-negative results. The simplicity and convenience of breath analysis make it an attractive alternative to analysis of faecal fat excretion in screening for fat malabsorption.

Adolescent↗
PubMed1981

Vitamin D supplements enhance weight gain and nutritional status in pregnant Asians.

In a double blind trial of supplementary vitamin D (1000 iu daily) administered in the last trimester of pregnancy to Asian women living in London, supplemented mothers gained weight faster (63.3 g/day) than those in the control group (46.4 g/day), and at term had significantly higher plasma levels of retinol binding protein and thyroid binding prealbumin indicating better protein-calorie nutrition. Maternal weight gain correlated with postpartum levels of both retinol binding protein and thyroid binding prealbumin. Almost twice as many infants in the unsupplemented group weighed under 2500 g at birth, and had significantly lower retinol binding protein levels than infants of supplemented mothers. The nutritional benefits of supplementation provide further support for the routine administration of vitamin D to all British Asians during pregnancy.

Asia↗