The nature of the Ca2+-pump defect in the red blood cells of patients with cystic fibrosis.

The reduction in (Ca2+ + Mg2+)-ATPase activity in the cystic fibrosis red blood cells can be attributed to a reduction in the number of active Ca2+ pumps per red blood cell and an altered interaction of calcium ions with the pump. Despite this, the normal free intracellular [Ca2+] is preserved due to a lower rate of passive calcium entry.

South-east asian ovalocytic (SAO) erythrocytes have a cold sensitive cation leak: implications for in vitro studies on stored SAO red cells.

South-east Asian ovalocytosis (SAO) results from the heterozygous presence of an abnormal band 3, which causes several alterations in the properties of the erythrocytes. Although earlier studies suggested that SAO erythrocytes are refractory to invasion in vitro by the malarial parasite Plasmodium falciparum, a more recent study showed that fresh SAO cells were invaded by the parasites, but became resistant to invasion on storage because intracellular ATP was depleted more rapidly than normal. Here we show that SAO red cells are much more leaky to sodium and potassium than normal red cells when stored in the cold. This leak was much less marked when the cells were stored at 25 or 37 degreesC. Incubation for 3.5 h at 37 degreesC of cold-stored SAO red cells did not restore sodium and potassium to normal levels, probably because the depleted ATP level in cold-stored SAO red cells is further reduced with incubation at 37 degreesC. The increased leakiness of SAO red cells is non-specific and extends to calcium ions, taurine, mannitol and sucrose. These results suggest that SAO red cells undergo a structural change on cooling. Since many of the reports describing altered properties of SAO red cells have used cells which have been stored in the cold, these results need re-evaluation using never-chilled SAO red cells to assess whether the cells have the same abnormal properties under in vivo conditions.

Cholesterol and arterial distensibility in the first decade of life: a population-based study.

BACKGROUND: Blood cholesterol levels are a key determinant of coronary heart disease risk in adults, but the importance of lipid levels in the general population during childhood is less clear. We related arterial distensibility, a marker of vascular function known to be altered early in atherosclerosis, to the lipid profile of a population-based sample of children aged 9 to 11 years. METHODS AND RESULTS: A noninvasive ultrasound technique was used to measure arterial distension during the cardiac cycle in the brachial arteries of 361 children from 4 towns in the United Kingdom. This measure was related to their pulse pressure to assess arterial distensibility. All the children had previously had a comprehensive assessment of cardiovascular risk including a full lipid profile, cotinine-assessed smoke exposure, serum glucose, and questionnaire data on socioeconomic and dietary factors. Mean total cholesterol in the population was 4.72 [SD 0.75] mmol/L. There was a significant, inverse relation between cholesterol and distension of the artery across this range (linear regression coefficient -11.8 microm. mmol(-1). L(-1), P=0.003). Similar relationships were demonstrated with LDL and apolipoprotein B (-12.9 microm. mmol(-1). L(-1), P=0. 005 and -36.9 microm/mmol/L, P=0.01). HDL and triglyceride levels showed no consistent association with distensibility. CONCLUSIONS: LDL cholesterol levels had an impact on arterial distensibility in the first decade of life. Furthermore, the functional differences in the arterial wall were demonstrated within the lipid range found in normal children, a finding that raises the possibility that cholesterol levels in the general population during childhood may already be relevant to the development of vascular disease.

Elevated plasma lipoprotein(a) is associated with coronary artery disease in patients with chronic stable angina pectoris.

OBJECTIVES: We sought to assess the relation between plasma lipoprotein(a) [Lp(a)] levels, clinical variables and angiographic coronary artery disease (CAD) in patients with chronic stable angina. BACKGROUND: The relation between plasma Lp(a) levels and the severity and extent of angiographic CAD has not been studied in well characterized patients with stable angina pectoris. METHODS: We investigated clinical variables, lipid variables and angiographic scores in 129 consecutive white patients (43 women) undergoing coronary angiography for chronic stable angina. RESULTS: Plasma Lp(a) levels were significantly higher in patients with than in those without significant angiographic stenoses (> or =70%) (372 mg/liter [interquartile range 87 to 884] vs. 105 mg/liter [interquartile range 56 to 366], respectively, p=0.002). This difference remained significant when patients with mild or severe angiographic disease were compared with those with completely normal coronary arteries (312 mg/liter [interquartile range 64 to 864] vs. 116 mg/liter [interquartile range 63 to 366], respectively, p=0.02). However, subset analysis indicated that this difference achieved statistical significance only in women. Multiple logistic regression analysis indicated that Lp(a) concentration was independently predictive of significant angiographic stenoses (adjusted odds ratio [OR] 9.1, 95% confidence interval [CI] 2.0 to 42.1, p=0.006) and remained true even after exclusion of patients receiving lipid-lowering treatment (n=27) (OR 10.4, 95% CI 1.1 to 102.9, p=0.05). Lp(a) also had independent predictive value in a similar analysis using mild or severe angiographic disease as the outcome variable (OR 11.8, 95% CI 1.5 to 90.8, p=0.02). CONCLUSIONS: Our results indicate that elevated plasma Lp(a) is an independent risk factor for angiographic CAD in chronic stable angina and may have particular significance in women.

A sensitive reverse passive haemagglutination immunoassay for hepatic caeruloplasmin.

A reverse passive haemagglutination assay for the measurement of caeruloplasmin in homogenates and organelle fractions prepared from needle biopsies of human liver tissue is described. Use of serial dilutions over a narrow range of concentrations permits accurate quantitation of caeruloplasmin down to 10 ng/ml, sufficient to detect the protein in needle biopsies with as little as 5 mg wet weight of tissue. Applied to the measurement of caeruloplasmin in human sera, the assay gives values which correlate well with those obtained by the standard radial immunodiffusion technique.

Western blot analysis in patients with hypocaeruloplasminaemia.

Inherited copper toxic disease, Wilson's disease, is an autosomal recessive disorder arising from a defect in biliary copper excretion. Although there are several pathognomonic clinical features, such a multisystem disease can be difficult to diagnose, particularly in the early stages of copper toxicity. Even measurements of serum copper and caeruloplasmin, the major copper-transporting protein typically reduced in Wilson's disease, may mimic other metabolic conditions such as Menke's disease and chronic active hepatitis. We have previously shown that the major biliary isoform of copper-transporting protein is 125 kDa caeruloplasmin, and this is always absent in the bile of Wilson's disease patients. In this paper we describe Western blot analysis of molecular species of caeruloplasmin in hypocaeruloplasminaemia, which can distinguish between the overlap which occurs in Wilson's disease homozygotes, heterozygotes and other conditions mimicking Wilson's disease. This may be useful for identifying patients with low plasma caeruloplasmin concentrations, and hepatic or neurological clinical features which may also be found in Wilson's disease.

Newborn screening for inborn errors of metabolism: a systematic review.

OBJECTIVES. To establish a database of literature and other evidence on neonatal screening programmes and technologies for inborn errors of metabolism. To undertake a systematic review of the data as a basis for evaluation of newborn screening for inborn errors of metabolism. To prepare an objective summary of the evidence on the appropriateness and need for various existing and possible neonatal screening programmes for inborn errors of metabolism in relation to the natural history of these diseases. To identify gaps in existing knowledge and make recommendations for required primary research. To make recommendations for the future development and organisation of neonatal screening for inborn errors of metabolism in the UK. HOW THE RESEARCH WAS CONDUCTED. There were three parts to the research. A systematic review of the literature on inborn errors of metabolism, neonatal screening programmes, new technologies for screening and economic factors. Inclusion and exclusion criteria were applied, and a working database of relevant papers was established. All selected papers were read by two or three experts and were critically appraised using a standard format. Seven criteria for a screening programme, based on the principles formulated by Wilson and Jungner (WHO, 1968), were used to summarise the evidence. These were as follows. Clinically and biochemically well-defined disorder. Known incidence in populations relevant to the UK. Disorder associated with significant morbidity or mortality. Effective treatment available. Period before onset during which intervention improves outcome. Ethical, safe, simple and robust screening test. Cost-effectiveness of screening. A questionnaire which was sent to all newborn screening laboratories in the UK. Site visits to assess new methodologies for newborn screening. The classical definition of an inborn error of metabolism was used (i.e., a monogenic disease resulting in deficient activity in a single enzyme in a pathway of intermediary metabolism). RESEARCH FINDINGS. INBORN ERRORS OF METABOLISM. Phenylketonuria (PKU) (incidence 1:12,000) fulfilled all the screening criteria and could be used as the 'gold standard' against which to review other disorders despite significant variation in methodologies, sample collection and timing of screening and inadequacies in the infrastructure for notification and continued care of identified patients. Of the many disorders of organic acid and fatty acid metabolism, a case can only be made for the introduction of newborn screening for glutaric aciduria type 1 (GA1; estimated incidence 1:40,000) and medium-chain acyl CoA dehydrogenase (MCAD) deficiency (estimated incidence 1:8000-1:15,000). Therapeutic advances for GA1 offer prevention of neurological damage but further investigation is required into the costs and benefits of screening for this disorder. MCAD deficiency is simply and cheaply treatable, preventing possible early death and neurological handicap. Neonatal screening for these diseases is dependent upon the introduction of tandem mass spectrometry (tandem MS). This screening could however also simultaneously detect some other commonly-encountered disorders of organic acid metabolism with a collective incidence of 1:15,000.(ABSTRACT TRUNCATED)

Monocyte expression of tissue factor and adhesion molecules: the link with accelerated coronary artery disease in patients with chronic renal failure.

OBJECTIVE: To investigate the expression of monocyte tissue factor (MTF) and adhesion molecules in patients with chronic renal failure (CRF) and to look for any correlation with thrombin generation and Lp(a) lipoprotein. DESIGN: A study of MTF expression and adhesion molecules, prothrombin fragments 1+2 (PTf1+2), an index of thrombin generation, and lipoproteins in patients with CRF and in normal control subjects. BACKGROUND: Patients with end stage renal failure have an increased risk of coronary artery disease despite advances in therapy. Stimulated monocytes are potent activators of blood coagulation through the generation of MTF, which was recently implicated in the aetiology of acute coronary ischaemic syndromes. METHODS: MTF expression and adhesion molecules were measured in whole blood using immunofluorescence of monocytes labelled with anti-tissue factor antibody and CD11b and c by flow cytometry. PTf1+2 and Lp(a) lipoprotein in plasma were measured by enzyme linked immunosorbent assay (ELISA). PATIENTS: 70 patients with CRF without documented coronary artery disease (30 patients with CRF undialysed, 20 patients undergoing chronic ambulatory peritoneal dialysis (CAPD), and 20 undergoing haemodialysis (HD)), together with 20 normal controls, were studied. RESULTS: The (mean (SD)) increased MTF of CRF (48.0 (29) v 33.3 (7.2) mesf unit/100 monocytes in controls, p = 0.04) was more pronounced in patients undergoing dialysis (HD 73.1 (32.8) (p < 0.003) and CAPD 62.8 (28.9) mesf unit/100 monocytes, p < 0.04). MTF activity showed a positive correlation with both PTf1+2 and serum creatinine (p < 0.003) but not with Lp(a) lipoprotein. Lp(a) lipoprotein was significantly increased in both dialysis groups compared with controls (p < 0.005) and non-dialysis CRF groups (p < 0.02). Monocyte adhesion molecule (CD11b) was significantly higher in all three CRF groups than in the controls (p = 0.006). CONCLUSION: This study has demonstrated a hypercoagulable state in patients with CRF. This was especially pronounced in the dialysis patients. These findings provide a possible explanation for the increased cardiovascular and cerebrovascular morbidity and mortality in these patients.

Secondary analysis of economic data: a review of cost-benefit studies of neonatal screening for phenylketonuria.

STUDY OBJECTIVE: To estimate the net financial benefit of neonatal screening for phenylketonuria (PKU): by a simple pooling of cost data from the literature; and by a more complex modelling approach. DESIGN: A systematic literature review was conducted to identify papers containing data on the monetary costs and benefits of neonatal screening for PKU. The methodological quality of the studies was appraised, and data were extracted on resource use and expenditure. Monetary data were converted to common currency units, and standardised to UK incidence rates. Net benefits were calculated for median, best case and worst case scenarios, and the effect of excluding poor quality studies and data was tested. The net benefit was also estimated from a model based on data from the literature and assumptions appropriate for the current UK situation. Extensive sensitivity analysis was conducted. MAIN RESULTS: The direct net benefit of screening based on the median costs and benefits from the 13 studies identified was 143,400 Pounds per case detected and treated (39,000 Pounds and 241,800 Pounds for worst case and best case scenarios respectively). The direct net benefit obtained by the modelling approach was lower at 93,400 Pounds per case detected and treated. Screening remained cost saving under sensitivity analysis, except with low residential care costs (less than 12,300 Pounds per annum), or very low incidence rates (less than 1 in 27,000). CONCLUSIONS: The economic literature on PKU screening is of variable quality. The two methods of secondary analysis lead to the same conclusion: that neonatal PKU screening is worthwhile in financial terms alone in the UK, and that it justifies the infrastructure for collecting and testing neonatal blood samples. This result cannot necessarily be extrapolated to other countries.

Polymorphisms in the gene encoding angiotensin 1-converting enzyme and relationship to its post-translational product in cerebral infarction.

There is increasing evidence to suggest that the gene encoding angiotensin 1-converting enzyme (ACE) plays a significant part in cardiac disease risk. It is not clear if this risk is due to atherosclerotic factors in general or whether its influence is local to cardiac tissue. Previous studies have suggested that there is a genetic control of plasma ACE levels in normal subjects. We sought to see if such a relationship also existed amongst computer tomography (CT) proven cerebral infarction. Twenty-eight patients with stroke and 19 control subjects were grouped according to their ACE genotype and their plasma ACE levels were assessed. Although there is a trend for plasma levels to be associated with the variant ACE alleles there was a wide overlap. However, when compared with their respective alleles in control subjects there was no difference. We conclude that any future evaluation of stroke risk from the ACE gene will need to determine both plasma ACE level and genotype.

Caeruloplasmin isoforms in Wilson's disease in neonates.

AIM: To investigate the neonatal diagnosis of Wilson's disease from caeruloplasmin isoforms in cord blood. METHODS: Serum caeruloplasmin isoforms were measured in 5-10 ml cord blood from 10 fresh umbilical cords using sodium dodecyl polyacrylamide gel electrophoresis (SDS PAGE) and western blotting and analysed by densitometry. Total caeruloplasmin concentrations were determined by nephelometry and caeruloplasmin oxidase by p-nitrophenyldiamine. RESULTS: Although total caeruloplasmin concentrations are reduced in neonates, the plasma isoform was significantly reduced or absent in patients with Wilson's disease. Sera from healthy neonates and from those with Wilson's disease had reduced biliary isoforms. CONCLUSION: Identification of caeruloplasmin isoforms may be a marker for Wilson's disease in neonates.

Acute renal failure after cardiopulmonary bypass: a possible association with drugs of the fibrate group.

BACKGROUND: Renal failure is a recognized, but infrequent, complication following cardiac surgery. The causes for this condition are multifactorial, and a major concern is that the occurrence of postoperative acute renal failure is still associated with a high mortality rate. METHODS AND MATERIALS: We report unexpected acute renal failure occurring in 4 patients after uncomplicated cardiac surgery. Each patient was taking a fibric acid derivative at the time of surgery. Renal failure occurred rapidly within 3 days of surgery and was associated with increased concentrations of skeletal muscle-derived creatine kinase (CK). One patient developed myoglobinuria, and another developed a malignant hyperthermia-like syndrome. CONCLUSIONS: These cases show that patients receiving lipid lowering medications could be at higher risk of developing acute renal failure after cardiac surgery. This association merits careful evaluation in large prospective studies and, if proved, would suggest that patients taking either statins or fibrates should discontinue doing so before cardiac surgery.

Association of Helicobacter pylori and Chlamydia pneumoniae infections with coronary heart disease and cardiovascular risk factors.

OBJECTIVE: To investigate the relation between seropositivity to chronic infections with Helicobacter pylori and Chlamydia pneumoniae and both coronary heart disease and cardiovascular risk factors. DESIGN: Cross sectional study of a population based random sample of men. Coronary heart disease was assessed by electrocardiography, Rose angina questionnaire, and a history of myocardial infarction; serum antibody levels to H pylori and C pneumoniae were measured, risk factor levels determined, and a questionnaire administered. SETTING: General practices in Merton, Sutton, and Wandsworth, south London. SUBJECTS: 388 white south London men aged 50-69. MAIN OUTCOME MEASURES: Evidence of coronary risk factors and infection with H pylori or C pneumoniae. RESULTS: 47 men (12.1%) had electrocardiographic evidence of ischaemia or infarction. 36 (76.6%) and 18 (38.3%) were seropositive for H pylori and C pneumoniae, respectively, compared with 155 (45.5%) and 62 (18.2%) men with normal electrocardiograms. Odds ratios for abnormal electrocardiograms were 3.82 (95% confidence interval 1.60 to 9.10) and 3.06 (1.33 to 7.01) in men seropositive for H pylori and C pneumoniae, respectively, after adjustment for a range of socioeconomic indicators and risk factors for coronary heart disease. Cardiovascular risk factors that were independently associated with seropositivity to H pylori included fibrinogen concentration and total leucocyte count. Seropositivity to C pneumoniae was independently associated with raised fibrinogen and malondialdehyde concentrations. CONCLUSIONS: Both H pylori and C pneumoniae infectins are associated with coronary heart disease. These relations are not explained by a wide range of confounding factors. Possible mechanisms include an increase in risk factor levels due to a low grade chronic inflammatory response.

Liver and gastrointestinal function in pregnancy.

Difficulties arise in the interpretation of liver tests in the pregnant subject, since some values increase (alkaline phosphatase) whilst others remain unchanged (transaminases) or fall during pregnancy. The diagnosis and management of some causes of jaundice in pregnancy, such as viral hepatitis, gall stones, benign intrahepatic cholestasis and acute fatty liver of pregnancy are discussed. Little is known about the commonest symptoms of pregnancy (nausea, vomiting and constipation) other than that they might be due to hormonally induced alteration of sphincter tone. However, pre-existing bowel disease has a greater effect on pregnancy. Fertility is reduced in poor nutritional states (e.g. coeliac and Crohn's diseases) and an increased occurrence of spontaneous abortion has been noted. For inflammatory bowel diseases, the time of onset is important in determining the outcome of pregnancy. Relapse in the disease is commonest in the first trimester and in the puerperium. Treatment of these conditions is essentially as in the non-pregnant subject. The controversial subject of sulphasalazine and steroid usage in pregnancy is discussed.