Mutation detection rate and spectrum in familial hypercholesterolaemia patients in the UK pilot cascade project.

Cascade testing using DNA-mutation information is now recommended in the UK for patients with familial hypercholesterolaemia (FH). We compared the detection rate and mutation spectrum in FH patients with a clinical diagnosis of definite (DFH) and possible (PFH) FH. Six hundred and thirty-five probands from six UK centres were tested for 18 low-density lipoprotein receptor gene (LDLR) mutations, APOB p.Arg3527Gln and PCSK9 p.Asp374Tyr using a commercial amplification refractory mutation system (ARMS) kit. Samples with no mutation detected were screened in all exons by single strand conformation polymorphism analysis (SSCP)/denaturing high performance liquid chromatography electrophoresis (dHPLC)/direct-sequencing, followed by multiplex ligation-dependent probe amplification (MLPA) to detect deletions and duplications in LDLR.The detection rate was significantly higher in the 190 DFH patients compared to the 394 PFH patients (56.3% and 28.4%, p > 0.00001). Fifty-one patients had inadequate information to determine PFH/DFH status, and in this group the detection rate was similar to the PFH group (25.5%, p = 0.63 vs PFH). Overall, 232 patients had detected mutations (107 different; 6.9% not previously reported). The ARMS kit detected 100 (44%) and the MLPA kit 11 (4.7%). Twenty-eight (12%) of the patients had the APOB p.Arg3527Gln and four (1.7%) had the PCSK9 p.Asp374Tyr mutation. Of the 296 relatives tested from 100 families, a mutation was identified in 56.1%. In 31 patients of Indian/Asian origin 10 mutations (two previously unreported) were identified. The utility of the ARMS kit was confirmed, but sequencing is still required in a comprehensive diagnostic service for FH. Even in subjects with a low clinical suspicion of FH, and in those of Indian origin, mutation testing has an acceptable detection rate.

Folic acid improves arterial endothelial function in adults with hyperhomocystinemia.

OBJECTIVES: To evaluate whether oral folic acid supplementation might improve endothelial function in the arteries of asymptomatic adults with hyperhomocystinemia. BACKGROUND: Hyperhomocystinemia is an independent risk factor for endothelial dysfunction and occlusive vascular disease. Folic acid supplementation can lower homocystine levels in subjects with hyperhomocystinemia; however, the effect of this on arterial physiology is not known. METHODS: Adults subjects were recruited from a community-based atherosclerosis study on healthy volunteers aged 40 to 70 years who had no history of hypertension, diabetes mellitus, hyperlipidemia, ischemic heart disease or family history of premature atherosclerosis (n = 89). Seventeen subjects (aged 54 +/- 10 years, 15 male) with fasting total homocystine levels above 75th percentile (mean, 9.8 +/- 2.8 micromol/liter) consented to participate in a double-blind, randomized, placebo-controlled and crossover trial; each subject received oral folic acid (10 mg/day) and placebo for 8 weeks, each separated by a washout period of four weeks. Flow-mediated endothelium-dependent dilation (percent increase in diameter) of the brachial artery was assessed by high resolution ultrasound, before and after folic acid or placebo supplementation. RESULTS: Compared with placebo, folic acid supplementation resulted in higher serum folate levels (66.2 +/- 7.0 vs. 29.7 +/- 14.8 nmol/liter; p < 0.001), lower total plasma homocystine levels (8.1 +/- 3.1 vs. 9.5 +/- 2.5 micromol/liter, p = 0.03) and significant improvement in endothelium-dependent dilation (8.2 +/- 1.6% vs. 6 +/- 1.3%, p < 0.001). Endothelium-independent responses to nitroglycerin were unchanged. No adverse events were observed. CONCLUSION: Folic acid supplementation improves arterial endothelial function in adults with relative hyperhomocystinemia, with potentially beneficial effects on the atherosclerotic process.

Hyperhomocyst(e)inemia is a risk factor for arterial endothelial dysfunction in humans.

BACKGROUND: Hyperhomocyst(e)inemia is associated with premature peripheral vascular, cerebrovascular, and coronary artery disease. Because homocysteine has been found to be damaging to endothelial cells in animal and cell culture studies, we evaluated the association between hyperhomocysteinemia and arterial endothelial dysfunction (a marker of early atherosclerosis) in asymptomatic adult subjects. METHODS AND RESULTS: Using high-resolution ultrasound, we measured endothelium-dependent flow-mediated dilation (EDD) and endothelium-independent nitroglycerin-induced dilation (GTN) of the brachial artery in 14 prospectively defined hyperhomocysteinemic (mean plasma homocysteine, 34.8+/-8.5 micromol/L), nonsmoking, healthy subjects aged 53+/-9 years and 14 control subjects with low plasma homocysteine levels (9.9+/-3.2 micromol/L). The two groups were well matched for age; sex; body mass index; blood pressure, blood cholesterol, folate, and vitamin B12 levels; and vessel diameter. EDD was significantly lower in hyperhomocysteinemic subjects (6.5+/-1.7%) than in subjects with low homocysteine levels (10.8+/-1.7%) (P<.001). GTN responses were similar in the two subject groups (P=.90). Multivariate analysis confirmed homocysteine level as the strongest predictor for impaired EDD, independent of age, sex, body mass index, or blood pressure, folate, vitamin B12, and cholesterol levels. CONCLUSIONS: Hyperhomocysteinemia is an independent risk factor for arterial endothelial dysfunction in healthy middle-aged adults.

Monoclonal gammopathy of unknown significance and malignant paraproteinemia in Hong Kong.

The incidence of multiple myeloma is lower in Southeast Asia than in the West. However, there are few reports on the overall incidence of paraproteinemia and its disease-associations in the Chinese. Therefore, the authors have correlated the laboratory features with the eventual clinical diagnosis in patients with paraproteinemia in a Hong Kong general/teaching hospital. Over 18 months, 1,600 patients were investigated for the presence of paraproteinemia. Paraproteinemia was detected in 157 (10%) patients. In 11 patients, investigations could not be completed. The remaining 146 patients were subjected to detailed clinical, radiologic, and laboratory investigations. Eighty-seven (59.6%) had monoclonal gammopathy of unknown significance (MGUS), 44 (30.1%) myeloma and 15 (10.3%) other lymphoproliferative disorder (LPD). There was no significant difference in the paraprotein concentration, frequency of hypogammaglobulinemia of Bence Jones proteinuria (BJP) or concentration of nonparaprotein immunoglobulin (Ig) between the myeloma and LPD groups. The overall kappa:lambda light chains ratios were 2.9, 1.6 and 3.3 in the MGUS, MM and LPD groups, respectively. Polyclonal Ig elevation was rare with myeloma (4.5%) but was detected in 33% of patients with LPD (P < .02) and 40% of those with MGUS (P < .0001). Biclonal (and one triclonal) gammopathy was detected in 11.5% of patients with MGUS, 11% with LPD and 4.5% with myeloma. In the MGUS group, infection was the commonest associated clinical disorder (29.3%). Moreover, 70% of patients with biclonal gammopathy and MGUS had an infection. Five of 15 patients with LPD had a T-cell malignancy, including 3 lymphomas and 2 large granular cell leukemias. Only one patient had primary systemic amyloidosis. It is concluded that the high frequency of biclonality and its association with infection, of paraproteinemia in association with T-cell malignancy and of kappa light chains in the MGUS and LPD groups are at variance with reports from the West and probably reflect local differences.

Hyperhomocysteinaemia and premature coronary artery disease in the Chinese.

OBJECTIVES: To examine the prevalence of hyperhomocysteinaemia and compare it with the classic risk factors and vitamin status in Hong Kong Chinese patients with premature atherosclerotic coronary artery disease. DESIGN: Case-control study. SETTING: General hospital and community. SUBJECTS: Forty five patients (39 males) with significant coronary artery disease confirmed by angiography (32 post myocardial infarction) and 23 healthy volunteers (17 male), all aged less than 55 years. INTERVENTION: Standardised methionine-loading test. MAIN OUTCOME MEASURES: Coronary artery disease, risk factors. RESULTS: More patients than controls had fasting hyperhomocysteinaemia (10/45 v 2/23, P = 0.122), post-methionine hyperhomocysteinaemia (17/45 v 1/23, P = 0.008), and an abnormal response to methionine (15/45 v 1/23, P = 0.015). A history of smoking was more frequent in patients (3/23 v 25/45, P = 0.002). Sixteen of 17 patients with hyperhomocysteinaemia but only nine of 28 with normohomocysteinaemia were smokers (P = 0.0002). Fasting plasma cholesterol concentrations (mean (SD)) were higher in hyperhomocysteinaemic patients (6.41 (1.58) mmol/l) than in controls (5.53 (0.90) mmol/l) (P = 0.042). Serum vitamin B-12 was not reduced and serum folate was higher in hyperhomocysteinaemic patients (35 (4) nmol/l) than normohomocysteinaemic patients (26 (9) nmol/l) (P = 0.009). CONCLUSIONS: Although the prevalence of hyperhomocysteinaemia in Hong Kong Chinese is similar to that in white subjects, hyperhomocysteinaemia is not an independent risk factor for coronary artery disease and is associated with smoking. This may be of some consequence in view of the change to a more Western diet with more animal protein, and therefore methionine, coupled with a high frequency of cigarette smokers in this region. The causes of the hyperhomocysteinaemia are multifactorial but in this pilot study a deficiency of folate and/or vitamin B-12 did not seem to be one of them.

Fatal acute hepatorenal failure following potassium permanganate ingestion.

Potassium permanganate (KMnO4), a powerful oxidizing agent, is readily available without prescription. Tissue contact produces coagulation necrosis and the lethal consequences of oral ingestion are well described, with most deaths because of airway oedema and obstruction or circulatory collapse. Whilst systemic toxicity is reported, its mechanism is unclear. We describe a case of suicidal ingestion of KMnO4 followed by acute hepatorenal toxicity resulting in the death of the patient. The clinical course bore close resemblance to that of severe paracetamol overdose. We discuss the pathogenesis of the systemic toxicity of KMnO4 and postulate that it is due to oxidative injury from free radicals generated by the absorbed permanganate ion. We recommend that N-acetyl cysteine be given within the first few hours to all patients with potassium permanganate poisoning.

Water and sodium disorders following surgical excision of pituitary region tumours.

A prospective observational study of the pathophysiology of sodium and water disorders in patients with pituitary region tumours after surgical excision was carried out in 20 patients. Serial pre-operative and post-operative fluid and sodium balance, plasma and urine elctrolyte biochemistry and their derived parameters, and circulating hormones associated with fluid balance, atrial natriureic peptide (ANP) and antidiuretic hormone (ADH) were documented to correlate with the patients' clinical conditions. Ten out of these twenty cases developed diabetes insipidus (DI) requiring ADH replacement therapy, although in the majority (6 cases), this way only a transient event. Of the nine patients who developed hyponatraemia, six had symptoms such as impaired consciousness and convulsions. Four patients developed alternating hypoatraemia and hypernatraemia, which constituted a difficult group, where appropriate sodium and fluid management, and ADH replacement therapy were based upon twice daily plasma and urine biochemistry and their derived parameters. Whilst DI in this group of patients was the result of a low circulating ADH level, hyponatraemia was not associated with an exaggerated ADH activity (6.0 +/- 2.3 vs 7.4 +/- 2.3 pmol/ml, mean +/- SEM). Rather, hyponatraemia was strongly associated with an elevated circulating ANP concentration (82.4 +/- 10.5 vs 30.0 +/- 3.1 pmol/ml, mean +/- SEM, p < 0.001), resulting in salt wasting and hypovolaemia.

Alpha-1-antitrypsin phenotypes and associated disease patterns in neurological patients.

INTRODUCTION: Alpha-1-antitrypsin (AAT) deficiency is usually associated with lung or liver disease. It is often detected as a qualitative reduction of the alpha-1 band on the serum protein electrophoretic pattern. MATERIAL AND METHODS: We examined the protein electrophoretic pattern in sera of 22980 unselected consecutive patients with neurological disorders and noted a reduced alpha-1 band in 88. Their phenotypes were compared with the clinical disease. RESULTS: 75 patients had a deficient or non-M and 13 the usual MM phenotype. Contrary to in the general population, PiMZ was four times more common than PiMS. Vascular disease was more common in patients with PiMZ while multiple sclerosis significantly more frequent in patients with PiMS than with other phenotypes, including PiMM. CONCLUSIONS: Other genetic abnormalities have previously been found in AAT associated with multiple sclerosis, but not PiMS. Since PIMS leads to modest reduction of AAT activity, the association may be through other mechanisms than reduced protease activity.

Antiepileptic drug pharmacokinetics and neuropharmacokinetics in individual rats by repetitive withdrawal of blood and cerebrospinal fluid: phenytoin.

The temporal pharmacokinetic (blood) and neuropharmacokinetic (cerebrospinal fluid, CSF) interrelationship of phenytoin was studied after acute and during chronic (up to 5 days) intraperitoneal administration of phenytoin (30, 50 or 100 mg/kg) using a new freely behaving rat model. After administration, phenytoin rapidly appeared in both serum (Tmax mean range 0.15-0.38 h) and CSF (Tmax mean range 0.9-1.4 h), suggesting ready penetration of the blood-brain barrier. However, transport across the blood-brain barrier may be rate limiting since whilst phenytoin concentrations rose dose dependently in serum, CSF concentrations did not. Further, the divergence between the blood and CSF compartments increased with chronic dosing. Cmax, AUC and t1/2 values for serum increased non-linearly, suggestive of accumulation kinetics. Based on these data, high initial phenytoin blood concentrations are essential if phenytoin entry into the brain is to be facilitated, and this may be important in studies of phenytoin in animal models of status epilepticus.

IgD multiple myeloma with thoracic spine compression due to epidural extra-osseous tumour spread.

On initial presentation of a patient with IgD multiple myeloma there were no features to suggest an unusual variant. Two months later she developed spinal cord compression due to an IgD plasmacytoma. This complication of IgD myeloma has rarely been reported. During the course of the disease and using the routine laboratory protocol for investigating and identifying paraproteins, including IgD, the patient's results became indistinguishable from those in Bence-Jones proteinuria myeloma.

A freely moving and behaving rat model for the chronic and simultaneous study of drug pharmacokinetics (blood) and neuropharmacokinetics (cerebrospinal fluid): hematological and biochemical characterization and kinetic evaluation using carbamazepine.

A freely moving and behaving rat model for the chronic and simultaneous study of drug pharmacokinetics (blood) and neuropharmacokinetics [cerebrospinal fluid (CSF)] is described. The blood (jugular vein) and CSF (cisterna magna) catheters employed are simple, reliable, and inexpensive. The blood catheter was made of soft and flexible Silastic tubing and sealed with heparin. The CSF catheter consisted of intersliding polythene tubing and interlocking Silastic tubing, which allowed maneuverability within the cisternal magna space and thus prolonging patency for chronic studies. Both catheters were well tolerated by the animals, and the postoperative success rate was 80%-100%; after 8 days 80%-85% of catheters were still patent. Using a sampling protocol considered suitable for kinetic studies, we determined numerous biochemical and hematological parameters and compared them with those values obtained postsurgically and in control rats. The parameter changes associated with the sampling protocol did not affect the kinetics of the commonly prescribed antiepileptic drug carbamazepine and its primary pharmacologically active metabolite carbamazepine-10, 11-epoxide. Therefore, the model can be used to study the interrelationship between drug kinetics at central and peripheral sampling sites and mechanism(s) of drug action.

Value of urinary copper excretion after penicillamine challenge in the diagnosis of Wilson's disease.

To investigate the diagnostic value of 24-hr urinary copper excretion testing after penicillamine challenge in the diagnosis of Wilson's disease, 75 consecutive children referred for a variety of liver problems and in whom parameters of copper metabolism had been investigated were analyzed retrospectively. Seventeen had Wilson's disease, 22 had autoimmune chronic active hepatitis, 6 had primary sclerosing cholangitis, 12 had chronic liver disease of various etiologies, 4 had cryptogenic acute liver failure, 6 had acute hepatitic illnesses and 8 had a variety of disorders featuring normal liver histological appearance. Serum ceruloplasmin and total copper levels were significantly lower in Wilson's disease patients compared with all other groups, but three children with Wilson's disease had normal ceruloplasmin levels and seven had normal total copper levels. No significant difference was found for free serum copper levels and liver copper content between Wilson's disease patients and the other groups. Baseline 24-hr urinary copper excretion was significantly higher in Wilson's disease patients compared with that of the other patients, but six children with Wilson's disease had levels just above the upper limit of normal, overlapping with values obtained in three children with liver failure, two with acute hepatitis, two with autoimmune chronic active hepatitis and three with primary sclerosing cholangitis. The 24-hr urinary copper excretion after penicillamine challenge proved the most accurate single diagnostic test; levels more than 25 mumol/24 hr were present in 15 of 17 patients with Wilson's disease, but in only 1 child with liver failure of the 58 with other disorders.(ABSTRACT TRUNCATED AT 250 WORDS)

Hyponatraemia in neurosurgical patients: diagnosis using derived parameters of sodium and water homeostasis.

Seventeen unselected, consecutive patients with intracranial disease and accompanying hyponatraemia were studied. All would previously have been diagnosed as having the syndrome of inappropriate antidiuretic hormone (ADH) secretion on the basis of spot plasma/urinary electrolyte testing with the application to them of existing standard laboratory criteria. Timed urinary collections and matching plasma samples were available in all but three cases for the derivation of creatinine, osmotic and free-water clearances, tubular reabsorbed water, and fractional water and sodium excretions. In a number of patients the plasma renin, aldosterone and ADH levels were also assayed. On the basis of the overall findings, 13 patients were diagnosed as in fact having a salt-wasting state whilst in only four patients was the diagnosis of inappropriate ADH secretion (SIADH) substantiated. It is suggested that obtaining simple derived parameters of sodium and water homeostasis can add significantly in differentiating between these quite opposite syndromes.

Cerebral neoplastic angioendotheleosis complicated by hypercalcaemia.

This is a case report of a 67 year old man who presented with a fluctuating level of consciousness and myoclonic jerks caused in part by hypercalcaemia. The diagnosis of cerebral neoplastic angioendotheleosis was only made later on brain biopsy and is the first report of the occurrence of hypercalcaemia in neoplastic angioendotheleosis.

Transient nephrotic syndrome after anaesthesia resulting from a familial cryofibrinogen precipitating at 35 degrees C.

Transient nephrotic syndrome, haematuria, and cryofibrinogenuria in a child after anaesthesia were found in association with a plasma cryofibrinogen that precipitated at 35 degrees C. Investigation of the family showed this to be a familial trait probably with dominant inheritance.

Chronic neurological toxicity associated with exposure to volatile substances.

1. The main neurological disorders associated with chronic VSA are peripheral neuropathy, cerebellar disease, chronic encephalopathy and dementia. Apart from peripheral neuropathy, the clinical features are non-specific, evidence for solvent-related toxicity is in most cases circumstantial and there is no clear dose/response relationship. 2. Peripheral neuropathy is mainly associated with n-hexane and methyl n-butyl ketone. 3. Cerebellar disease is usually associated with toluene exposure; in the more severe cases there is often radiological evidence of irreversible cerebellar atrophy. 4. Chronic encephalopathy and dementia are the most serious consequence of solvent exposure, particularly to toluene in abusers and to mixed solvents in industrial workers. Postmortem studies in some abusers have shown generalized axonal degeneration, demyelination and brain atrophy. 5. Further studies on low level solvent exposure are needed as little is known about the neurological consequences of mild VSA, especially as regards individual susceptibility and possible interactions between solvents and other toxins such as ethanol.

An intra-erythrocytic low molecular weight lead-binding protein in acute and chronic lead exposure and its possible protective role in lead toxicity.

A low-molecular-weight protein was measured in erythrocytes from workers with chronic and recent lead exposure, with and without clinical lead toxicity, and from a group of control subjects not exposed to undue environmental lead. The protein was detected in all the workers, but in significantly smaller amounts in those with symptoms, and was absent from controls. The synthesis of the protein is induced at blood lead concentrations above 1.9 mumol/L, but is reduced in workers susceptible to clinical lead toxicity at blood lead concentrations below 4.0 mumol/L. The activity of the red blood cell dithiothreitol (DTT)--activated 5-aminolaevulinate dehydratase (ALA-D) was correlated with the concentration of the low-molecular-weight protein, with both being particularly low in the symptomatic workers. Previous studies have shown that the protein binds lead. By sequestrating excess lead into a non-toxic form, the protein may have a protective role in preventing clinical, and reducing biochemical, lead toxicity.

Cerebral depression due to propylene glycol in a patient with chronic epilepsy--the value of the plasma osmolal gap in diagnosis.

A case of propylene glycol poisoning is described in a 39 year old woman which resulted in her admission to hospital in status epilepticus. She had had a long-standing history of uncontrollable epilepsy. The diagnosis of propylene glycol poisoning resulted directly from the finding of a high plasma osmolal gap on admission. This finding would have been missed if later samples only had been analysed. Plasma osmolality and the osmolal gap should be considered first line investigations in patients presenting with metabolic acidosis and cerebral signs and symptoms. Since her discharge from hospital a year ago the patient has had no further seizures.