Prenatal diagnosis of Machado-Joseph disease by direct mutation analysis

MJD is the most frequent dominant ataxia and an incapacitating disorder. Onset is most frequently during the reproductive years, and genetic counseling is its only means of prevention. The causative mutation--an expansion of a (CAG)n on chromosome 14q32.1--can now be directly detected. We now report the first two cases of prenatal diagnosis (PND). The first presented as a simultaneous request for predictive testing and PND at 14 weeks of pregnancy. Owing to time constraints, we performed a full protocol of counseling with shorter inter between sessions, while psycho-social evaluation of the other parent obstetric consults were also begun. We ensured that the couple wished termination if the fetus was a carrier, to avoid a presymptomatic test for the unborn child. We were thus able to deliver test results two weeks before PND. As the fetus carried an expanded allele (77 CAGs) inherited from his father, termination was performed and the couple received counselling, psychological and social support. The second case was the fetus of a carrier-mother that was diagnosed as non-carrier, also after amniocentesis.

Influence of stiripentol on cytochrome P450-mediated metabolic pathways in humans: in vitro and in vivo comparison and calculation of in vivo inhibition constants

OBJECTIVE

The spectrum of cytochrome P450 inhibition of stiripentol, a new anticonvulsant, was characterized in vitro and in vivo.

METHODS

Stiripentol was incubated in vitro with (R)-warfarin, coumarin, (S)-warfarin, (S)-mephenytoin, bufuralol, p-nitrophenol, and carbamazepine as probes for CYPs 1A2, 2A6, 2C9, 2C19, 2D6, 2E1, and 3A4, respectively. Caffeine demethylation and the 6 beta-hydroxycortisol/cortisol ratio were monitored in vivo before and after 14 days of treatment with stiripentol as measures of CYP1A2 and CYP3A4 activity, and dextromethorphan O- and N-demethylation were used to measure CYP2D6 and CYP3A4 activity, respectively. In vivo inhibition constants for CYP3A4 were calculated with use of data that previously documented the interaction between stripentol and carbamazepine.

RESULTS

In vitro, stiripentol inhibited CYPs 1A2, 2C9, 2C19, 2D6, and 3A4, with inhibition constant values at or slightly higher than therapeutic (total) concentrations of stiripentol, but it did not inhibit CYPs 2A6 and 2E1 even at tenfold therapeutic concentrations. In vivo inhibition of caffeine demethylation and dextromethorphan N-demethylation were consistent with inhibition of CYP1A2 and CYP3A4, respectively. The 6 beta-hydroxycortisol/cortisol ratio did not provide a reliable index of CYP3A4 inhibition. Inhibition of CYP2D6-mediated O-demethylation was not observed in vivo. With use of carbamazepine, in vivo inhibition constants for CYP3A4 ranged between 12 and 35 mumol/L, whereas the corresponding in vitro value was 80 mumol/L.

CONCLUSIONS

Stiripentol appears to inhibit several CYP450 enzymes in vitro and in vivo. In vivo inhibition constants show that stiripentol inhibition of CYP3A4 is linearly related to plasma concentration in patients with epilepsy.

13C-urea breath test for Helicobacter pylori: cut-off point determination by cluster analysis

1. This study was performed on a large set of 13C-urea breath test results to determine the optimal cut-off point of the test for the diagnosis of Helicobacter pylori (Hp) infection. 2. The following steps were applied to three sets of urea breath test results obtained in three groups of subjects (696 adults before anti-Hp treatment, 1056 adults after anti-Hp treatment and 173 children under 17 years of age): (1) demonstrate the distribution of urea breath test results as a mix of two normal populations (Hp negative and Hp positive) by logarithmic transformation of the results in each group of subjects; (2) apply statistical cluster analysis to determine the separation point between Hp-negative and -positive populations; (3) calculate the mean and SD of each population, and use these parameters in the equation of the normal distribution to establish the frequency curves of Hp-negative and -positive populations; and (4) determine the cut-off point of the urea breath test as the intersection of the two curves, and the risks of error related to it. 3. The optimal cut-off point was found at +3.00 delta/1000, with a risk of false-negative or -positive response of the urea breath test of less than 3%. From this, a cut-off point of +3.00 delta/1000 for the 13C-urea breath test is recommended, with an indetermined zone between +2.5 and +3.5 delta/1000 to account for the spontaneous variation of 13CO2 in breath and the limits of GC-isotope ratio-MS analytical precision.

Combined endarterectomy of the internal carotid artery and persistent hypoglossal artery: an unusual case of carotid revascularization

Persistence of the hypoglossal artery is an unusual congenital abnormality of the carotid arterial system, and the simultaneous occurrence of atheromatous disease in the internal carotid artery and persistent hypoglossal artery is even more uncommon. Carotid surgery in this situation is challenging, and the surgeon must be aware of potential inherent pitfalls. A 74-year-old woman with asymptomatic stenosis of both internal carotid and hypoglossal arteries associated with occlusion of the contralateral internal carotid artery underwent successful revascularization. The anatomy of this unusual lesion and the surgical strategies, which included cranial nerve dissection and mandibular subluxation, are reviewed.

Continuous monitoring of 13C-aminopyrine metabolism in rats: effects of cold exposure and noradrenaline

A system was developed to allow constant monitoring of hepatic cytochrome P450 activity in awake and unrestrained rats. A continuous 13C-aminopyrine perfusion was performed, and breath samples obtained for endogenous CO2 production and 13C measurements, to calculate 13C O2 production due to aminopyrine demthylation. Increasing doses of 13C-aminopyrine produced a hyperbolic increase of expired 13CO2, compatible with an in vivo measurement of enzymatic activity. Acute-cold exposure of the rats during 13C-aminopyrine perfusion produced a two-fold increase of endogenous CO2 production, together with a 27% increased 13C-aminopyrine metabolism (p<0.05 vs basal conditions). In contrast, noradrenaline (20 microg/kg BW/min), despite a similar effect on energy expenditure, did not significantly change 13C-aminopyrine metabolism. Acute-cold exposure is known to stimulate both adrenal catecholamine secretion and the sympathetic nervous system. The observed difference in 13C-aminopyrine demthylation during cold exposure and nonadrenaline perfusion, therefore, could be due to a more specific effect of adrenal catecholamines on liver aminopyrine metabolism. These results suggest the possibility of prolonged in vivo monitoring of liver metabolism pathways such as aminopyrine demethylation, thus allowing the study of drug acute interactions with cytochrome P450 system.

Impact of the development of a multidisciplinary adverse drug reaction committee

A multidisciplinary Adverse Drug Reaction (ADR) committee consisting of pharmacists, nurses, and physician was formed. The committee developed an ADR Reporting Form and a 24-hour ADR Reporting Hotline to simplify ADR Reporting throughout the hospital. An ADR Newsletter and an extensive inservice education program was also implemented. Suspected ADRs are investigated by a pharmacist and presented to committee. A formal report is then forwarded to the Pharmacy and Therapeutics Committee, as well as the clinical departments within the hospital. The establishment of a formalized multidisciplinary ADR committee was successful in generating 2.1 ADR reports per 100 hospital admissions. These ADRs were reported from a variety of healthcare professionals.

Absence of mutations in superoxide dismutase and catalase genes in patients with Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is an adult-onset, neurodegenerative disorder characterized by a selective loss of the dopaminergic cells of the substantia nigra and by progressive motor decline. Studies have shown aberrant oxidative stress metabolism within the substantia nigra and other dopaminergic regions of the brain in patients with PD.

OBJECTIVE

To screen the genes of three free radical detoxifying enzymes--copper/zinc superoxide dismutase, manganese superoxide dismutase, and catalase--for mutations in patients with PD.

PATIENTS AND METHODS

A total of 107 unrelated patients with PD from two PD populations (familial and sporadic) were screened for mutations in the genes of copper/zinc superoxide dismutase, manganese superoxide dismutase, and catalase by single-strand conformation analysis. The diagnosis of PD was based on the clinical observations of resting tremor, rigidity, and bradykinesia.

RESULTS

No mutations were identified. However, we did identify an amino acid substitution (glycine to aspartic acid) in exon 9 of the catalase gene in one patient; decreased red blood cell catalase activity was observed in this patient.

CONCLUSION

Parkinson's disease is not caused by mutations in the genes of these three detoxifying enzymes. The exon 9 variant in the catalase gene in the one family with PD is most likely a silent mutation and not the genetic cause of PD in this family.

Aminopyrine breath test: development of a 13C-breath test for quantitative assessment of liver function in humans

BACKGROUND/AIM

14C-aminopyrine breath test (ABT) has been shown to be well correlated to the severity of liver diseases, but its use is limited in countries where radioactive isotopes are severely controlled. The goal of this study was to develop a 13C-ABT based on a highly sensitive method to measure 13CO2 in breath samples.

MATERIALS AND METHODS

The relevant parameters were studied in 26 controls and 27 patients: the 13CO2 enrichment of expired breath between t-10 and t+60 minutes was determined as the most simple and clinically useful parameter. The 13C-ABT was then prospectively compared to clinico-biological data and the galactose elimination capacity (GEC) in 82 patients.

RESULTS

The 13C-ABT was well correlated to: i) the Child-Pugh classification; ii) GEC results; iii) the hepatic volume. The presence of ascites or alcoholic consumption did not alter significantly the results of the test. 13C-ABT appeared more sensitive than GEC to evaluate minor liver dysfunctions.

CONCLUSIONS

The 13C-ABT is a simple and sensitive test to measure liver function. The use of the stable isotope 13C ensures the harmlessness of the test and the possibility to repeat it in a given patient.

Characterization of the non-functional Fas ligand of gld mice

Mice homozygous for either the gld or lpr mutation develop autoimmune diseases and progressive lymphadenopathy. The lpr mutation is characterized by the absence of functional Fas, whereas gld mice exhibit an inactive FasL due to a point mutation proximal to the extracellular C-terminus. The structural repercussions of this amino acid substitution remain unknown. Here we report that FasL is expressed at similar levels on the surface of activated T lymphocytes from gld and wild-type mice. Using a polyclonal anti-FasL antibody, indistinguishable amounts of a 40 kDa protein are detected in both gld and wild-type splenocytes. The molecular model of FasL, based on the known structure of TNF-alpha, predicts that the Phe --> Leu gld mutation is located at the protomer interface which is close to the FasR interaction site. We conclude that the gld mutation allows normal FasL biosynthesis, surface expression and oligomerization, but induces structural alterations to the Fas binding region leading to the phenotypic changes observed.

Theophylline pharmacokinetics and metabolism in rabbits following single and repeated administration of Capsicum fruit

Pharmacokinetics and metabolism of theophylline were studied in three groups of male rabbits, after intravenous administration (12 mg/kg), with and without oral ground Capsicum fruit suspension. Compared with control values, plasma theophylline half-life of distribution and of elimination, areas under plasma curves, clearance and volume of distribution did not show any significant difference. On the contrary, the elimination rate constant (k1,0) is significantly different (0.01 < P < 0.05) after a single dose of capsicum and remained unchanged after a repeated dose. Concerning the metabolism of theophylline in rabbits, the results showed that the oral administration of a single dose of Capsicum fruit suspension does not significantly affect the urinary excretion of theophylline and its metabolites--1,3-dimethyluric acid (1,3-DMU) and 1-methyluric acid (1-MU). On the other hand, after a repeated dose of Capsicum fruit for 7 days, the quantity of 1-MU was significantly reduced (0.01 < P < 0.05). In conclusion, it was found that a single dose of Capsicum fruit could affect pharmacokinetic parameters of theophylline (k1,0), while a repeated dose affected the metabolic pathway of xanthine oxidase.

Human hepatic macrovesicular steatosis: a noninvasive study of mitochondrial ketoisocaproic acid decarboxylation

Differentiating between alcoholic and nonalcoholic hepatic steatosis is often a difficult clinical task. However, decreased fatty acid mitochondrial oxidation appears as the main factor for alcoholic steatosis, whereas nonalcoholic steatosis may be due to other causes. We studied mitochondrial function, based on a 13C-ketoisocaproic acid (13C-KIC) breath test, in nine alcoholic and 12 nonalcoholic steatosis patients and 10 healthy volunteers. Our results showed a 42% 13C-KIC decarboxylation decrease in alcoholic steatosis patients, but not in nonalcoholic steatosis patients. This noninvasive breath test appears helpful for the diagnostic work-up of hepatic steatosis.

[Clinical study of a population of patients hospitalized for eating disorders. Discussion of DSM III-R diagnostic criteria]

Patients consecutively referred for a clinical diagnosis of eating disorders to the Unit for Addictive Disorders at the University Hospital of Nantes were included in the study. The sample contained 95 patients (94 females, 1 male; mean age +/- SD: 24.1 +/- 6.5). All the patients were evaluated with the Computerized Multiple Diagnostic Instrument for Eating Disorders, which assesses diagnostic criteria for eating disorders from different international diagnostic classifications. Seven (7%) patients fulfilled the DSM III-R criteria for anorexia nervosa (AN) and 42 (44%) the DSM III-R criteria for bulimia nervosa. Two subgroups of bulimic patients were distinguished according to Body Mass Index [anorexia-bulimia (AB) if BMI was < 18 (n = 11, 12%) and normal weight bulimia (NWB) if BMI was > 18 (n = 31, 33%)]. Most patients (n = 46, 48%) did not fulfill DSM III-R criteria for AN or bulimia, and were given the residual DSM III-R diagnosis of eating disorder not otherwise specified (EDNOS). A comparison was made of the frequencies of the different weight control strategies displayed by the patients of the 4 subgroups. Vigorous exercise was more frequently used by AN patients than by patients of the 3 other subgroups. Vomiting was more frequent in bulimic patients, although this symptom was displayed by 29% of the AN patients and 24% of the EDNOS. Abuse of laxatives or diuretics was similar in the four subgroups. Use of diuretics was infrequent in the total sample of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanism of carbon tetrachloride autoprotection: an in vivo study based on 13C-aminopyrine and 13C-galactose breath tests

This study was conducted to evaluate in vivo the hepatotoxic effects of CCl4 administration to rats using 13C breath tests: aminopyrine breath test (ABT) was used to monitor CCl4-induced cytochrome P450 inactivation, and galactose breath test (GBT) to quantitatively measure the CCl4-induced decrease of liver function. The ABT results showed profound aminopyrine demethylation inhibition lasting for three days and complete recovery at day 7, while GBT results were decreased only one day after CCl4. The protection induced by a first CCl4 dose against a second one paralleled cytochrome P450 inactivation: a second CCl4 dose given three days after the first one induced no GBT decrease and a mild increase of serum transaminase activities. On the other hand, the second dose administered 7 days after the first one produced a GBT decrease similar to the one observed after the first one. These results should be taken into consideration to determine the optimal CCl4 dosing schedule in the rat CCl4-induced cirrhosis model.

The neurofibromatosis type 2 gene is inactivated in schwannomas

Schwannomas are tumors arising from schwann cells surrounding peripheral nerves. Although most schwannomas are sporadic, they are seen in approximately 90% of individuals with neurofibromatosis type 2 (NF2), an autosomal dominantly inherited disease with an incidence of 1:40000 live births. The NF2 gene has recently been isolated on chromosome 22 and encodes a putative membrane organizing protein named schwannomin. It is believed to act as a tumor suppressor gene based on the high frequency of loss of heterozygosity (LOH) on this autosome in both sporadic and NF2 associated schwannomas and meningiomas and the identification of inactivating mutation in NF2 patients. In this study we examined 61 schwannomas including 48 sporadic schwannomas (46 of which are vestibular schwannomas) and 12 schwannomas obtained from NF2 patients, for mutations in 10 of the 16 coding exons of the NF2 gene. Twelve inactivating mutations were identified, 8 in sporadic tumours and 4 in tumors from people with NF2. These results support the hypothesis that loss of function of schwannomin is a frequent and fundamental event in the genesis of schwannomas.

Natural history and patterns of current practice in heart failure. The Studies of Left Ventricular Dysfunction (SOLVD) Investigators

A total of 6,273 consecutive relatively unselected patients with heart failure or left ventricular dysfunction, or both (mean age 62 +/- 12 years, mean ejection fraction 31 +/- 9%), were enrolled in the Studies of Left Ventricular Dysfunction (SOLVD) Registry over a period of 14 months. All patients were followed up for vital status and hospital admissions at 1 year. Ischemic heart disease was the underlying cause of failure or dysfunction in approximately 70% of patients, whereas hypertensive heart disease was considered to be primarily involved in only 7%. There were striking differences in the etiology of heart failure among blacks and whites: 73% of whites had an ischemic etiology of failure versus only 36% of blacks; 32% of blacks had a hypertensive condition versus only 4% of whites. The total 1-year mortality rate was 18%; 19% of patients had hospital admissions for heart failure and 27% either died or had a hospital admission for congestive heart failure during the 1st year of follow-up. Factors related to 1-year mortality or hospital admission for congestive heart failure included age, ejection fraction, diabetes mellitus, atrial fibrillation and female gender. There was no difference in mortality associated with congestive heart failure among blacks and whites, but hospital admissions for heart failure were more frequent in blacks. Digitalis and diuretic agents were the drugs most often used in these patients, who were often taking many medications in relation to severity of congestive heart failure symptoms and ejection fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of enalapril on myocardial infarction and unstable angina in patients with low ejection fractions

An association between raised renin levels and myocardial infarction has been reported. We studied the effects of enalapril, an angiotensin-converting enzyme (ACE) inhibitor, on the development of myocardial infarction and unstable angina in 6797 patients with ejection fractions < or = 0.35 enrolled into the two Studies of Left Ventricular Dysfunction (SOLVD) trials. Patients were randomly assigned to placebo (n = 3401) or enalapril (n = 3396) at doses of 2.5-20 mg per day in two concurrent double-blind trials with the same protocol. Patients with heart failure entered the treatment trial (n = 2569) and those without heart failure entered the prevention trial (n = 4228). Follow-up averaged 40 months. In each trial there were significant reductions in the number of patients developing myocardial infarction (treatment trial: 158 placebo vs 127 enalapril, p < 0.02; prevention trial: 204 vs 161 p < 0.01) or unstable angina (240 vs 187 p < 0.001; 355 vs 312, p < 0.05). Combined, there were 362 placebo group patients with myocardial infarction compared with 288 in the enalapril group (risk reduction 23%, 95% CI 11-34%; p < 0.001). 595 placebo group patients developed unstable angina compared with 499 in the enalapril group (risk reduction 20%, 95% CI 9-29%, p < 0.001). There was also a reduction in cardiac deaths (711 placebo, 615 enalapril; p < 0.003), so that the reduction in the combined endpoint of deaths, myocardial infarction, and unstable angina was highly significant (20% risk reduction, 95% CI 14-26%; p < 0.0001). Enalapril treatment significantly reduced myocardial infarction, unstable angina, and cardiac mortality in patients with low ejection fractions.

Clinical characteristics of patients in studies of left ventricular dysfunction (SOLVD)

The Studies of Left Ventricular Dysfunction (SOLVD) trials were designed to evaluate the effects of enalapril on long-term mortality in patients with severe left ventricular (LV) dysfunction. Patients with LV ejection fractions less than or equal to 0.35 and symptoms of congestive heart failure (CHF) were enrolled in the treatment trial, whereas those with no history of overt CHF and taking no treatment directed for LV dysfunction were enrolled in the prevention trial. The baseline clinical characteristics of SOLVD patients were compared to characterize differences between patients in these 2 separate but concurrent trials. From over 70,000 patients screened with LV dysfunction, 4,228 patients were enrolled in the prevention trial and 2,569 patients in the treatment trial. Ischemic heart disease was the primary cause of LV dysfunction in both prevention (83%) and treatment (71%) trial patients. Prior myocardial infarction was present in 80% of the prevention and 66% of the treatment trial patients (p less than 0.001). In the prevention trial, infarction was recent (less than or equal to 6 months) in 27% patients and remote (greater than 6 months) in 57% patients. Treatment trial patients had proportionately more women (20 vs 13%; p less than 0.001) and non-Caucasians (20 vs 14%; p less than 0.001), as well as the coexisting risk factors of hypertension (42 vs 37%; p less than 0.001) and diabetes (26 vs 15%; p less than 0.001) than did prevention trial patients. Clinical characteristics of patients in both trials were influenced by the gender and race of enrolled patients. Similarly, coronary artery bypass surgery was performed less often in women and non-Caucasians.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative Study of 35 Bacteriophages of Lactobacillus helveticus: Morphology and Host Range

This survey included 23 phages isolated from cheese whey and 12 temperate phages induced with mitomycin from their lysogenic host strains. All of the phages had an isometric head and a tail with a contractile sheath. In addition, short-tailed (160-nm-long) and long-tailed (260-nm-long) phages were distinguished. Short-tailed phages were by far the most widespread in French cheese factories (32 of the 35 phages studied). The study of phage relationships enabled two large groups of strains to be distinguished: those not or slightly sensitive to phages and those very sensitive to phages. There was an obvious relationship in the first group between phage sensitivity (or resistance) and the geographic origin of the strains. The second group contained primarily strains from large international collections and those isolated from commercial starters. The relationships among short-tailed phages, either temperate or isolated as lytic, suggest that lysogenic strains could be the major source of phages in French cheese factories.

Localization of Peptidases in Lactococci

The localization of two aminopeptidases, an X-prolyl-dipeptidyl aminopeptidase, an endopeptidase, and a tripeptidase in Lactococcus lactis was studied. Polyclonal antibodies raised against each purified peptidase are specific and do not cross-react with other peptidases. Experiments were performed by immunoblotting after cell fractionation and by electron microscopy of immunogold-labeled peptidases. All peptidases were found to be intracellular. However, immunogold studies showed a peripheral labeling of the X-prolyl-dipeptidyl aminopeptidase, the tripeptidase, and the endopeptidase. This peripheral location was further supported by the detection of these three enzymes in cell membrane fractions in which none of the two aminopeptidases was present.