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Biomedical subjects

J D Maxwell

Publications and source records attributed to J D Maxwell.

At least 55 records · Page 3Linked to original sources
PubMed1995

Vegetarian diet as a risk factor for tuberculosis in immigrant south London Asians.

BACKGROUND: In a previous retrospective study of tuberculosis in south London among Asian immigrants from the Indian subcontinent Hindu Asians were found to have a significantly increased risk for tuberculosis compared with Muslims. This finding has been further investigated by examining the role of socioeconomic and lifestyle variables, including diet, as risk factors for tuberculosis in Asian immigrants from the Indian subcontinent resident in south London. METHODS: Using a case-control study technique Asian immigrants from the Indian subcontinent diagnosed with tuberculosis during the past 10 years and two Asian control groups (community and outpatient clinic controls) from the Indian subcontinent were investigated. Cases and community controls were approached by letter. A structured questionnaire concerning a range of demographic, migration, socioeconomic, dietary, and health topics was administered by a single trained interviewer to subjects (56 cases and 100 controls) who agreed to participate. RESULTS: The results confirmed earlier findings that Hindu Asians had an increased risk of tuberculosis compared with Muslims. However, further analysis revealed that religion had no independent influence after adjustment for vegetarianism (common among Hindu Asians). Unadjusted odds ratios for tuberculosis among vegetarians were 2.7 (95% CI 1.1 to 6.4) using community controls, and 4.3 (95% CI 1.8 to 10.4) using clinic controls. There was a trend of increasing risk of tuberculosis with decreasing frequency of meat or fish consumption. Lactovegetarians had an 8.5 fold risk (95% CI 1.6 to 45.4) compared with daily meat/fish eaters. Adjustment for a range of other socioeconomic, migration, and lifestyle variables made little difference to the relative risks derived using either community or clinic controls. CONCLUSIONS: These results indicate that a vegetarian diet is an independent risk factor for tuberculosis in immigrant Asians. The mechanism is unexplained. However, vitamin D deficiency, common among vegetarian Asians in south London, is known to affect immunological competence. Decreased immunocompetence associated with a vegetarian diet might result in increased mycobacterial reactivation among Asians from the Indian subcontinent.

Adult↗
PubMed1994

Salivary antibodies to Helicobacter pylori: screening dyspeptic patients before endoscopy.

Diagnostic tests on saliva have advantages compared with those on serum. In 119 consecutive dyspeptic patients referred for endoscopy we developed and validated an enzyme-linked immunosorbent assay to detect salivary immunoglobulins to Helicobacter pylori. Salivary IgG distinguished positive and negative cases (p < 0.0001), but salivary IgA did not. The optimum performance of salivary IgG (85%) was similar to that of serum IgG (90%) and better than that of salivary IgA. Using our assay and a history of regular use of non-steroidal anti-inflammatories in screening patients under 45 years, we detected all peptic ulcers while saving 39% of endoscopies.

Adolescent↗
PubMed1994

Soluble intercellular adhesion molecule-1 in primary biliary cirrhosis: relationship with disease stage, immune activity and cholestasis.

Intercellular adhesion molecule-1, strongly expressed on the interlobular and proliferating bile ducts in primary biliary cirrhosis, is important in the migration and adhesion of inflammatory cells from the circulation to these structures. A soluble form has been found to be elevated in serum in primary biliary cirrhosis. Our aim was to check on the role of soluble intercellular adhesion molecule-1 in primary biliary cirrhosis with particular reference to its specificity by comparison with other disease control groups and to assess its relationship with stage of disease activity, circulating lymphocyte activation and cholestasis. Soluble intercellular adhesion molecule-1 (enzyme-linked immunosorbent assay) and liver biochemistry were measured in 41 patients with primary biliary cirrhosis, 9 with primary sclerosing cholangitis, 12 with alcoholic liver disease and 17 healthy controls. In subgroups of patients with primary biliary cirrhosis, lymphocyte activation and hepatic bile acid uptake and excretory rates were determined. Soluble intercellular adhesion molecule-1 was significantly higher in all three disease groups. Levels in primary biliary cirrhosis and primary sclerosing cholangitis were similar and significantly higher than alcoholic liver disease. Soluble intercellular adhesion molecule-1 expression was greater in late primary biliary cirrhosis than early disease and correlated with histological progression. Correlations were also found with alkaline phosphatase, gamma-glutamyl transpeptidase and conjugated bilirubin. A trend toward an inverse correlation with hepatic excretory rate was found, but no correlation was detected with circulating lymphocyte interleukin-2 receptor expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Kinetics of hepatic bile acid handling in cholestatic liver disease: effect of ursodeoxycholic acid.

BACKGROUND/AIMS: Ursodeoxycholic acid (UDCA) is clinically beneficial in chronic cholestatic liver disease, but the underlying mechanisms are unclear. It has been suggested that intrahepatic retention of endogenous hydrophobic bile acids contributes to cholestasis and that the hydrophilic bile acid UDCA reduces this retention; the aim of our study was to test these hypotheses. METHODS: Twelve patients with primary biliary cirrhosis (PBC) and 5 with primary sclerosing cholangitis (PSC) were studied before and during UDCA (10 mg.kg-1.day-1) and compared with 11 healthy controls. Following intravenous 75Se labeled homocholic acid taurine (75SeHCAT) in the fasting state, abdominal gamma camera imaging was performed for 90 minutes. Initial hepatic uptake, transit time, net, and absolute excretory rates for 75SeHCAT were measured. RESULTS: Mean initial hepatic uptake was not different between patients and controls (17.2% and 19.9% dose/minute, not significant). However, net and absolute excretory rates were significantly reduced in patients (1.4% vs. 3.7% dose/minute, P < 0.0001; and 2.35% vs. 3.96% dose/minute, P < 0.02, respectively), and hepatic transit time was prolonged (18.7 minutes vs. 11.6 minutes, P < 0.002). UDCA improved net and absolute hepatic excretory rates and transit time (1.43% to 1.96% dose/minute, P < 0.001; 2.35% to 3.15% dose/minute, P < 0.005 and 18.7 to 14.7 minutes, P < 0.001, respectively). However, UDCA did not alter initial hepatic uptake. CONCLUSIONS: In PBC and PSC, there is a defect in hepatic bile acid excretion but not in uptake, implying bile acid retention. This retention is reduced by UDCA.

Adult↗
PubMed1994

Effect of local inhibition of nitric oxide synthesis on forearm blood flow and dorsal hand vein size in patients with alcoholic cirrhosis.

1. Nitric oxide (NO) is a potent endogenous vasodilator and plays a role in the control of resting vascular tone. Patients with cirrhosis have a hyperdynamic circulation with reduced blood pressure and decreased peripheral resistance, and it is possible that increased production of NO due to induction of NO synthase may be involved in maintaining this vasodilatation. We have examined this possibility by studying the effects of local infusions of NG-monomethyl-L-arginine (an inhibitor of NO synthase) in the forearm arteriolar bed and the superficial dorsal hand veins of patients with alcoholic cirrhosis. 2. Drugs were either infused locally into the brachial artery and forearm blood flow was measured by venous occlusion plethysmography, or into a vein on the back of the hand and vein diameter was measured using a linear displacement technique. 3. Basal forearm blood flow was increased and vascular resistance was decreased in the patients with alcoholic cirrhosis compared with healthy control subjects. Noradrenaline and NG-monomethyl-L-arginine caused dose-dependent falls in forearm blood flow in both healthy control subjects and patients with cirrhosis. There was no significant difference in the responses to either noradrenaline or NG-monomethyl-L-arginine between the two groups. 4. In the superficial hand veins there was no change in vein size in response to NG-monomethyl-L-arginine infused alone, and venoconstriction to local infusion of noradrenaline was unaffected by co-infusion with NG-monomethyl-L-arginine. 5. Our results confirm that patients with alcoholic cirrhosis are vasodilated compared with healthy control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Effect of famotidine on oesophageal sensitivity in gastro-oesophageal reflux disease.

Gastric acid suppression could improve heartburn by healing oesophagitis or by reduction of oesophageal sensitivity to acid. To independently assess changes in oesophageal sensitivity, it would be necessary to study patients with reflux disease but no oesophagitis. The aim of this study was to investigate the effect of acid suppression on oesophageal sensitivity and to assess the time course of any measured effect. Twenty seven patients were recruited, of whom 25 completed the study (14 men and 11 women, mean (SD) age 50 (15) years). All had classic symptoms of gastro-oesophageal reflux but normal results of upper gastrointestinal endoscopy and oesophageal mucosal histological tests. Each had abnormal 24 hour pH studies and a positive acid perfusion tests. Subjects were assigned double blind to placebo (n = 11) or famotidine 40 mg twice daily (n = 14) for four weeks. Acid perfusion tests were carried out at 0, 4, 5, and 8 weeks and time to heartburn recorded. Time to heartburn (mean (SEM)) was 124 (78) seconds in the famotidine and 187 (154) in the placebo group at week 0 (NS). Compared with baseline, significant increases in time to heartburn was found with famotidine at weeks 4 (383 (102), p < 0.01) and 5 (344 (92), p < 0.01) but not week 8 (336 (90) seconds). No significant effects were found with placebo (219 (41), 146 (23), and 144 (25) seconds for weeks 4, 5, and 8). Heartburn symptom score decreased significantly with famotidine (mean scores 3.6, 1.9, 2.1, and 2.6 at weeks 0, 4, 5, and 8 (p=0.001)) and showed a significant negative correlation with time to heartburn (r(s)=-0.60; p<0.0001). It is concluded that oesophageal sensitivity to acid is reduced by famotidine independent of and effect on oesophagitis; the effect wanes one to four weeks after the end of treatment and correlates with change in heartburn score.

Adult↗
PubMed1994

Localisation of vitamin D receptor in normal human duodenum and in patients with coeliac disease.

Immunocytochemistry using a specific monoclonal antibody 9A7 gamma was used to identify receptors for calcitriol (1,25 (OH)2 D3), the active metabolite of vitamin D, in sections of duodenal mucosa. Specific staining for vitamin D receptors was largely restricted to nuclei of enterocytes lining crypts in duodenal biopsy specimens from normal mucosa. Vitamin D receptors were also abundant in crypts from duodenal mucosa in coeliac disease patients with mucosal damage and villous atrophy. In contrast, alkaline phosphatase, a vitamin D regulated protein, was absent from crypts but present on brush borders of normal villi, and on surface enterocytes in coeliac disease. Oestrogen receptor could not be identified in duodenal mucosa. These findings suggest that calcium malabsorption in coeliac disease does not result from the absence of vitamin D receptors, but rather from reduction in vitamin D regulated proteins and functions essential for active calcium absorption that are located in the enterocytes of the villi.

Alkaline Phosphatase↗
PubMed1993

Is clubbing a feature of the anti-phospholipid antibody syndrome?

A patient with the anti-phospholipid antibody syndrome and digital clubbing is described. No recognized cause for the clubbing was found. It is suggested that platelet aggregation and microthrombi formation as a result of anti-phospholipid antibody may be involved in the pathogenesis of the digital clubbing. This may be a new feature of the anti-phospholipid antibody.

Antiphospholipid Syndrome↗
PubMed1993

Physicians' attitudes to the autopsy.

The overall autopsy rate (excluding coroner's autopsies) at a large teaching district general hospital over a four year period was 16.5%, but individual rates for ten general physicians varied from 5% to 35%. During this period, the mean autopsy rate for general medicine (14%) was significantly lower than rates for cardiology (21%), geriatrics (23%) and paediatrics (36%), but similar to general surgery (13%). Autopsies were widely perceived as being of benefit to education and research, but physicians were often unaware of their value for confirming the diagnosis and for clinical audit, and over-estimated their actual autopsy rates on average by 50%. High rates (18-30%) were associated with consultants who had a definite policy regarding autopsies and had made this clear to their junior staff. Low rates (6-10%) obtained where there was no consultant policy on autopsies, and were frequently attributed by the consultant physicians to failure by their junior staff. Physicians should be more aware of the value of autopsies, and should take responsibility for increasing and monitoring autopsy requests to improve clinical audit, quality assurance and medical education.

Attitude of Health Personnel↗
PubMed1992

Determinants of pregnancy heartburn.

OBJECTIVE: To study the prevalence and severity of reflux symptoms in pregnancy. DESIGN: Self-administered questionnaire detailing age, race, gestational age, parity, weight, height, symptoms and severity of gastro-oesophageal reflux. SETTING: An antenatal clinic in a teaching hospital. SUBJECTS: 607 consecutive women at various stages of pregnancy were recruited during attendance at antenatal clinic. RESULTS: The prevalence of heartburn increased with gestational age (22% in the first, 39% in the second, and 72% in the third trimester; P < 0.0001), as did severity of heartburn (P < 0.0001). Pharyngeal regurgitation as a symptom showed little increase during advancing pregnancy. Symptoms of heartburn rapidly increased towards the end of the second trimester. The decrease in heartburn traditionally expected during the last three weeks of pregnancy (fetal head descent) was not observed. Logistic regression analysis showed increased risk of suffering heartburn with increasing gestational age (P < 0.0001), pre-pregnancy heartburn (P < 0.0001), parity (P < 0.0001) and inversely with maternal age (P < 0.05) but not with body mass index before pregnancy, race, or weight gain in pregnancy. CONCLUSION: Heartburn, but less so pharyngeal regurgitation, increases in prevalence and severity with gestational age and parity. We speculate that hormone-related impairment of distal oesophageal clearance mechanisms may have a crucial bearing on whether heartburn develops in those individuals at greatest risk.

Adult↗
PubMed1992

Osteomalacia should be sought and treated before withdrawal of anticonvulsant therapy in UK Asians.

Individuals from the Asian sub-continent in the United Kingdom are at particular risk of developing osteomalacia. We report a Gujarati woman who developed osteomalacia whilst taking anticonvulsant drugs; withdrawal of anticonvulsant therapy was followed by a seizure complicated by femoral neck fracture. In patients with other risk factors for osteomalacia, as is the case for Asians living in Britain, anticonvulsant drugs should not be reduced or withdrawn until osteomalacia, which puts the skeleton at increased risk of fracture, and its associated hypocalcaemia, which reduces seizure threshold, have been sought and adequately treated.

Adult↗
PubMed1992

Clinical and histological spectrum of osteomalacia among Asians in south London.

In a prospective study of 175 adult Asian patients attending a medical out-patient clinic we found a spectrum of metabolic bone disease. Twenty-four patients (13.5 per cent) had definite osteomalacia, of whom 11 (6 per cent) had severe clinical osteomalacia on the basis of associated symptoms and radiological signs. Fifteen (8.5 per cent) had borderline osteomalacia, while the remaining 136 (78 per cent) had normal bone biopsy, or were presumed to be normal. This histological spectrum was paralleled by the increasing prevalence of musculoskeletal symptoms (thigh pain, change in gait and difficulty rising from seated position) attributable to osteomalacia. Multivariate analysis showed that the major determinant of osteomalacia in Asians in South London was vegetarian diet. Increasing severity of bone disease was associated with increasingly strict vegetarian practice, which accounted for the excess risk of females, Hindus, and Asians originating from East Africa. Covering skin when outdoors also contributed to the female excess risk, and suggested a role for reduced solar exposure. Clinically significant osteomalacia is underdiagnosed in the Asian population, but evidence of dietary adaptation suggests this problem may diminish with time.

Adult↗
PubMed1992

Blunted seasonal variation in serum 25-hydroxy vitamin D and increased risk of osteomalacia in vegetarian London Asians.

Serum 25-hydroxy vitamin D levels were measured in 297 adult Asians and 68 white subjects at different times of year and seasonal variation compared between subjects grouped according to ethnic origin, religion and dietary habit. A sub-group of Asians with symptoms and biochemical changes suggestive of osteomalacia underwent bone biopsy, and static bone histomorphometry was performed. Histological osteomalacia was detected in 15 Asians and borderline changes in 13. The majority of these cases were among vegetarian Hindus. Significant seasonal variation in 25-hydroxy vitamin D was observed in all groups, but with lower peak and trough levels among Asians, and especially the Hindus and vegetarian Asians. Summer rises in 25-hydroxy vitamin D levels were blunted among Hindus and vegetarian Asians, compared to whites, Muslims and non-vegetarian Asians. Vegetarian Asians had significantly lower serum calcium and higher PTH levels than non-vegetarians, but multivariate analysis indicated that this was an effect of osteomalacia, not vegetarianism. We conclude that solar exposure has a significant effect on vitamin D status in Asians resident in London. Non-vegetarian Asians have similar rise and peak levels to whites, but those taking a vegetarian diet (in particular, Hindus) have an impaired seasonal rise in 25-hydroxy vitamin D levels, and are at particular risk of metabolic bone disease. This effect did not appear to be mediated through secondary hyperparathyroidism consequent on a vegetarian diet.

Adult↗
PubMed1991

Comparison of liver histology with ultrasonography in assessing diffuse parenchymal liver disease.

To establish the accuracy of ultrasonography in assessing diffuse parenchymal liver disease we performed a prospective comparative study with histology in 50 patients with a wide range of liver disease. Liver biopsy was performed within 24 h of the ultrasound examination and ultrasonography was performed by a single operator who was unaware of clinical details of the patients. Histology was reviewed blind and the degree of steatosis graded mild, moderate or severe while increased portal fibrous tissue was graded mild, moderate or established cirrhosis. Thirty-six patients had steatosis and 31 patients had increased fibrous tissue on histology. Ultrasonography correctly identified steatosis in 32/36 (89%) patients including all patients with the severe grade. Increased fibrous tissue was correctly identified in 24/31 (77%) with a sensitivity of 100% in patients with moderate fibrosis and established cirrhosis. Specificity was 93% for steatosis and 89% for increased fibrous tissue. These results show that ultrasonography can provide a non-invasive prediction of liver histology which in moderate and severe steatosis and advanced fibrosis can be both highly sensitive and specific.

Biopsy, Needle↗