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Biomedical subjects

M Lambert

Publications and source records attributed to M Lambert.

At least 109 records · Page 6Linked to original sources

[Takayasu's arteritis: vascular investigations and therapeutic management. Experience with 16 patients].

PURPOSE: There is no consensus in regard to vascular explorations and therapeutical management of Takayasu's arteritis. The objective of this study was therefore to establish the most appropriate vascular explorations and to analyze current treatments. METHODS: Clinical, biological and morphological findings related to either diagnosis or treatment were retrospectively evaluated in sixteen patients diagnosed with Takayasu's arteritis according to the American College of Rheumatology criteria. RESULTS: Median delay between the occurrence of the first symptoms and the diagnosis was 9 months. Aortic lesions and aortic valvular incompetence were more frequent. Statistical analysis showed the existence of a correlation between the lack of relapse and corticosteroid therapy (Fisher exact test, P = 0.021). Percutaneous transluminal angioplasty led to stabilization of vascular lesions. Surgical management led to satisfactory results, except for patients with aortic lesions, as survival was then less than 1 year. CONCLUSION: Early diagnosis is mandatory in patients with Takayasu's arteritis in order to propose appropriate therapy, particularly corticosteroid therapy. Surgery and angioplasty prove to be useful in occlusive forms. Late diagnosis is accompanied by severe aortic lesions and fatal outcome.

Adult↗

Mutation at the phenylalanine hydroxylase gene (PAH) and its use to document population genetic variation: the Quebec experience.

We describe variation at the PAH locus in the population of Quebec. We successfully analyzed 135 of 141 chromosomes from phenylketonuria (PKU) probands (95.7% of the sample), and eight additional chromosomes from a small number of probands with non-PKU hyperphenylalaninemia (HPA). The full set of chromosomes harboured 45 different PAH mutations: i) seven polymorphisms (IVS2nt19, IVS3nt-22, IVS6nt-55, Q232Q, V245V, L385L, Y414Y); ii) four mutations causing non-PKU HPA (T92I, E390G, R408Q, D415N); iii) 34 mutations causing PKU. Only six mutations (M1V, R261Q, F299C, S349P, R408W and IVS12nt1) occurred in the whole province at relative frequencies > 5%: most are rare and probably identical by descent. By studying associations of mutations with polymorphic haplotype alleles, we found examples of mutations on different haplotypes that were identical by state, but not by descent because they were recurrent mutations (E280K and R408W); and examples of mutations identical both by state and by descent because of intragenic recombination (S67P, G218V, V245A and IVS12nt1). Ten mutations were first described in Quebec and five are still unique there; three of these 'Quebec' mutations are reported here for the first time (c.125A-->T (K42I); [c.470G-->A; c.471A--C] (R157N); c.707nt-55 (IVS6nt-55). The PAH mutations stratify by geographic region and population, their distributions validating hypotheses about European range expansion to North America during three separate phases of immigration and demographic expansion in the Quebec region over the past four centuries. The PAH homozygosity value (j) is 0.06 for the total Quebec sample (0.5-0.08 by regions), and the corresponding homoallelic fraction of mutant PAH genotypes is 24%. These findings are a documentation of genetic diversity in the Quebec population.

Alleles↗

Impact of ethnicity on the prevalence of psychiatric disorders among migrants in Germany.

OBJECTIVES: Studies on psychiatric disorders among migrants have described higher rates, especially of schizophrenia. Some evidence points to the possibility of misdiagnosis for this higher rate; other studies point to the underrepresentation of migrants in psychiatric services, leading to artefactual epidemiological data. METHODS: All admission records of migrants to a psychiatric clinic from 1993 to 1995 were assessed for diagnosis, symptomatology and treatment. RESULTS: Admissions of 408 migrants, 8.1% of total admission, were assessed. Of these, 38.7% received a diagnosis of a schizophrenic disorder, significantly more than the other clinic patients. The mean age at admission was 34.0 years, at onset of illness 28.6 years and at time of migration 20.4 years. Only 8.3% were mentally ill at the time of migration. Language problems correlated with the diagnosis of a schizophrenic disorder. CONCLUSION: An underrepresentation of migrants shows differences in the use of psychiatric services. Some evidence from the mental status and reported language problems may explain the higher rate of schizophrenia due to misdiagnosis.

Adult↗

Chronic aortic dissection masquerading as systemic disease.

We report two cases of chronic aortic dissection whose prominent features were characterized by systemic symptoms (prolonged low grade fever, fatigue, weight loss) and biological acute phase response. In the first patient, a surgical repair of the descending thoracic aorta aneurysm was performed, allowing the disappearance of general manifestations, whereas spontaneous resolution occurred in the second case. Although aortic dissection is usually an acute and highly symptomatic event, the disorder can present--albeit rarely--as systemic illness and fever of unknown origin.

Acute-Phase Reaction↗

Antiviral activity of a selective ribonucleotide reductase inhibitor against acyclovir-resistant herpes simplex virus type 1 in vivo.

The present study reports the activity of BILD 1633 SE against acyclovir (ACV)-resistant herpes simplex virus (HSV) infections in athymic nude (nu/nu) mice. BILD 1633 SE is a novel peptidomimetic inhibitor of HSV ribonucleotide reductase (RR). In vitro, it is more potent than ACV against several strains of wild-type as well as ACV-resistant HSV mutants. Its in vivo activity was tested against cutaneous viral infections in athymic nude mice infected with the ACV-resistant isolates HSV type 1 (HSV-1) dlsptk and PAAr5, which contain mutations in the viral thymidine kinase gene and the polymerase gene, respectively. Following cutaneous infection of athymic nude mice, both HSV-1 dlsptk and PAAr5 induced significant, reproducible, and persistent cutaneous lesions that lasted for more than 2 weeks. A 10-day treatment regimen with ACV given topically four times a day as a 5% cream or orally at up to 5 mg/ml in drinking water was partially effective against HSV-1 PAAr5 infection with a reduction of the area under the concentration-time curve (AUC) of 34 to 48%. The effects of ACV against HSV-1 dlsptk infection were not significant when it was administered topically and were only marginal when it was given in drinking water. Treatment under identical conditions with 5% topical BILD 1633 SE significantly reduced the cutaneous lesions caused by both HSV-1 dlsptk and PAAr5 infections. The effect of BILD 1633 SE against HSV-1 PAAr5 infections was more prominent and was inoculum and dose dependent, with AUC reductions of 96 and 67% against infections with 10(6) and 10(7) PFU per inoculation site, respectively. BILD 1633 SE also significantly decreased the lesions caused by HSV-1 dlsptk infection (28 to 51% AUC reduction). Combination therapy with topical BILD 1633 SE (5%) and ACV in drinking water (5 mg/ml) produced an antiviral effect against HSV-1 dlsptk and PAAr5 infections that was more than the sum of the effects of both drugs. This is the first report that a selective HSV RR subunit association inhibitor can be effective against ACV-resistant HSV infections in vivo.

Acyclovir↗

Clara cell protein (CC16) in pleural fluids: a marker of leakage through the visceral pleura.

Pleural fluid (PF) proteins either derive from serum by diffusion or are locally secreted within the pleural space. Another hypothetical origin is a leakage of lung secretory proteins across the visceral pleura. To test this hypothesis, we investigated the occurrence, sources, and determinants in PF of CC16, a small-size and readily diffusible protein of 16 kDa secreted by bronchiolar Clara cells. CC16 concentration was determined by a sensitive latex immunoassay in serum and PF of 117 subjects (86 exudates and 31 transudates) and, for purpose of comparison, in ascites samples from another group of 38 subjects (7 exudates and 31 transudates). CC16 was also studied in serum and PF of normal rats and in rats with pleural exudate induced by alpha-naphthyl-thiourea (ANTU). The levels of CC16 in PF and ascites were highly correlated with that in serum, suggesting a diffusional exchange across the pleural/blood and peritoneal/blood barriers. Whereas CC16 occurs at similar levels in ascites and serum, the protein was found to be more concentrated in PF than in serum in both humans (geometric mean in microg/L, 26.2 versus 14.6, p < 0.0001) and rats (213 versus 16.2, p < 0.001). A local synthesis of CC16 appeared unlikely in view of the lack of CC16-immunostaining in pleura of both species. The only plausible explanation for these findings is that CC16 in PF originates from two sources: diffusion from plasma and a leakage from the lung into the pleural space across the semipermeable visceral pleura. This interpretation is supported by a markedly increased leakage of CC16 in experimental exudates induced by ANTU and the finding of high CC16 concentrations in human transudates associated with congestive heart failure, two conditions wherein PF has been shown to arise from the interstitial spaces of the lung.

Aged↗

Detection of false-positive sera in contagious agalactia with a multiantigen ELISA and their elimination with a protein G conjugate.

In serology, lack of specificity can generally be attributed to cross-reactions between different pathogens with antigens bearing similar epitopes. During seroepidemiologic surveys of contagious agalactia of sheep caused by Mycoplasma agalactiae infection, numerous sera were analyzed by enzyme-linked immunosorbent assay (ELISA). A few sera reacted with various antigens coated on plates, including the well with no antigen. This reactivity was not due to cross-reactions as initially suspected, and these multipositive sera were designated false-positive sera. Elimination of this false positivity was not possible by using covalent ELISA plates or different rabbit anti-sheep IgG conjugates. Only conjugates using monoclonal antibodies or protein G were efficient in elimination of false positivities without reducing the true specific positive titers. No false-positive sera have been observed since the implementation of protein G conjugates in the serologic diagnosis of contagious agalactia by ELISA for the past 2 years.

Animals↗

Hypoleptinemia in patients with anorexia nervosa: loss of circadian rhythm and unresponsiveness to short-term refeeding.

Leptin is a protein encoded by the ob gene that is expressed in adipocytes and regulates eating behavior via neuroendocrine mechanisms. Plasma leptin levels have been shown to correlate with weight and body fat in normal, obese and anorexic subjects. In the last of these populations, the dynamic profile of plasma leptin levels during short-term refeeding has never been assessed. We thus investigated basal plasma leptin levels in 29 female patients with anorexia nervosa (AN) (age 21.9 +/- 1.4 years, body mass index (BMI) 15.2 +/- 0.3 kg/m2) and in 80 normal female controls (age 21.2 +/- 0.2 years, BMI 20.3 +/- 0.3 kg/m2, mean +/- S.E.M.). Basal plasma leptin levels in AN were decreased by 77% compared with controls (2.5 +/- 0.2 vs 11.1 +/- 0.7 ng/ml, P < 0.0001). In both AN subjects and controls, plasma leptin levels correlated significantly with BMI (r2 = 0.448, P < 0.0001 and r2 = 0.339, P < 0.0001 respectively). Five AN patients (four female, one male, age 22.0 +/- 4.7 years, BMI 14.2 +/- 0.4 kg/m2, body fat 4.3 +/- 0.9 kg or 11.0 +/- 1.9% of body weight, basal metabolic rate (BMR) 958 +/- 122 kcal/day) were studied during a 3-day refeeding period and compared with eight control subjects (two male, six female, age 25.7 +/- 1.2 years, BMI 21.3 +/- 0.8 kg/m2, body fat 15.1 +/- 0.9 kg or 24.6 +/- 1.7%, BMR 1455 +/- 78 kcal/day) submitted to 36-h fasting. The amount of calories administered was based on BMR + 20% (carbohydrate 60%, protein 17%, fat 23%). In contrast to the rise in leptin levels that occurred during refeeding after a prolonged fast period in normal subjects, plasma leptin levels remained low and unchanged throughout the 3 days of renutrition in AN patients. The circadian rhythm of leptin was also completely abolished. This contrasted with the preserved circadian variations of cortisol, whose mean levels were increased. In conclusion, we confirmed that plasma leptin levels are low in AN and correlate with body weight. We further demonstrated that plasma leptin levels do not respond to short-term refeeding in anorexic patients in whom circadian variations are not restored, which suggests that the acute regulation of leptin by positive changes in energy balance is not preserved under a critical threshold of body fat.

Adult↗

Takayasu's arteritis diagnosed at the early systemic phase: diagnosis with noninvasive investigation despite normal findings on angiography.

We describe a case of Takayasu's arteritis discovered at the early systemic phase. Ultrasonography and computed tomography show thickening of the walls of the superior mesentery and common carotid arteries despite normal findings on angiography. Diagnosis was confirmed by arterial biopsy. We emphasize the importance of noninvasive vascular investigation to support the diagnosis of Takayasu's arteritis.

Adult↗

[Differential diagnosis of psychotic disorders in immigrants].

Several studies [5,6] on the prevalence of psychiatric disorders among migrants describe a higher rate of schizophrenic disorders. Other studies [2,3] as well as DSM-IV [1] point out that affective disorders with psychotic symptoms can be misdiagnosed as schizophrenic or schizoaffective disorders. We report on a patient admitted with the diagnosis of paranoid schizophrenia (ICD-10: F20.0), discussing differential diagnostic criteria and the problems of diagnosing along ICD-10 criteria.

Adult↗

[Cadherins, the development and regeneration of the neuromuscular axis].

Various cell adhesion molecules of the cadherin family characterize the neuromuscular system. During development, cadherins N and M are sequentially expressed by myogenic cells during the two waves of myoblast fusion. Two other cadherins, called 6 and 11, are also expressed during the embryonic musculature development. In adult muscle, cadherins N and M, whose expression is suppressed by muscle activity, persist only at the neuromuscular junction and are reexpressed at the surface of denervated fibers. Cadherins N, M and E are also expressed in adult peripheral nerves. Their differential localization at Schmidt-Lanterman clefts, Ranvier nodes and neuromuscular junctions suggest that these molecules contribute to the stabilization of specialized intercellular contacts. In conclusion, a combination of cadherins, the expression of which is spatially and temporally regulated, participates in the differentiation and maintenance of the organization of the various cellular and tissular components of the neuromuscular system.

Adult↗

Identification of two novel LDL receptor gene defects in French-Canadian pediatric population: mutational analysis and biochemical studies.

Familial hypercholesterolemia (FH) is at least twofold more prevalent in French Canadians from Québec than in most Western populations. Although our recent data confirmed this high frequency of heterozygous FH in our pediatric population with hypercholesterolemia, none of the five established molecular defects for the French-Canadian population was detected in 29% of the unrelated French-Canadian children characterized by a persistent increase in LDL (low density lipoprotein receptor) cholesterol and a positive parental history of hyperlipidemia (Assouline et al., 1995). To probe for new mutations, six of these molecularly undiagnosed children were investigated as index patients. By using single-strand conformation polymorphism analysis and DNA sequencing, two novel mutations were identified in two of these subjects: (1) 7-base pair (bp) duplication following nucleotide 681 (according to the cDNA sequence) in exon 4 (681ins7), which causes a frameshift, the introduction of a stop at codon 208, and premature chain termination, and (2) A to G change in exon 8 substituting a tyrosine for a cysteine at amino acid 354 (Y354C). A third subject carried the recently reported exon 10 mutation (Y468X), whereas the remaining three patients demonstrated various known polymorphisms with no effect on gene product. Rapid molecular assays were developed to detect the two new mutations as well as the Y468X mutation. Screening of our cohort showed heterozygosity in 1/88, in 2/88, and in 2/88 of patients for the 681ins7, the Y354C, and the Y468X mutations, respectively.

Amino Acid Sequence↗

Hematological changes in anorexia nervosa are correlated with total body fat mass depletion.

OBJECTIVE: To assess the relationships between total body fat mass (FM) and hematological abnormalities in anorexia nervosa (AN). METHOD: Peripheral blood parameters and body composition were determined in 10 anorectic patients and 19 age- and sex-matched healthy subjects. In patients with AN, magnetic resonance imaging (MRI) studies of bone marrow were also performed. RESULTS: Compared with controls, patients with AN had -41% body weight, -81% FM, -18.8% lean tissue mass (LTM), and -22.6% bone mineral content; they also had lower mean total leukocyte (4.52 +/- 0.47 vs. 6.28 +/- 0.33 x 10(3)/microliter, p < .005), neutrophil (2.45 +/- 0.34 vs. 3.46 +/- 0.20 x 10(3)/microliter, p < .005), monocyte (0.24 +/- 0.03 vs. 0.37 +/- 0.03 x 10(3)/microliter, p < .05), and platelet counts (184 +/- 17 vs. 238 +/- 9 x 10(3)/microliter, p < .005). Hemoglobin level was normal and comparable in both groups. In patients with AN, but not in controls, total leukocyte, neutrophil, eosinophil, and monocyte counts as well as hemoglobin level were highly correlated with FM expressed in absolute values or in percentage of body weight, but not with LTM. Moreover, AN patients with signal intensity patterns suggestive of serous atrophy of bone marrow at MRI had not only lower erythrocyte, leukocyte, neutrophil, and platelet counts, but they also had lower FM than AN patients with normal MRI patterns. DISCUSSION: Hematological changes in AN, as assessed by peripheral blood parameters and MRI patterns of bone marrow, are correlated with total body FM depletion, suggesting that the reduction of adipose tissue adversely affects hematopoiesis.

Adipose Tissue↗

Effect size of efficacy measures comparing divalproex, lithium and placebo in acute mania.

Effect size (ES) is a statistical concept that can be used to improve the interpretation of results from psychopharmacological studies. ES may aid interpretation of results when sample size is unbalanced or small or when units or levels of baseline measures differ across items. Usually, an investigator can define a threshold value for a clinically meaningful ES based on published data and clinical judgment or by resorting to conventions, e.g., a medium ES = 0.5 S.D., which can usually be discerned by the trained clinician. In the present study, we apply ES analysis to results from a study comparing the effectiveness of divalproex (DIVAL), lithium (LI), and placebo (PLA) in hospitalized, acutely manic patients. One hundred seventy-six patients were randomly assigned to DIVAL, LI, or PLA in a 2:1:2 ratio, with drug administered in a double-blind, parallel group design for 21 days. The primary efficacy measure was the Mania Rating Scale from the Schedule for Affective Disorders and Schizophrenia, composed of the Manic Syndrome Score (MSS) from items that are relatively specific to the manic state, and the Behavior and Ideation Score (BIS), which reflects severe but nonspecific psychopathology. Improvement of the MSS after 5 days of treatment was difficult to interpret based on percentage change (DIVAL = 19%, LI = 13.5%, PLA = 8.5%). However, the corresponding effect sizes of 0.79, 0.55, and 0.35 indicated a medium to marked ES for DIVAL, a medium ES for LI, and a small ES for PLA at this early point in treatment. Similarly, the ES for change on the MSS at the end of treatment indicated a large, readily observable improvement with both DIVAL (ES = 1.01) and LI (ES = 0.79) vs. an ES of 0.37 for PLA. ES analysis also indicated that the BIS is a less robust indicator of change to either drug. The ES at the end of treatment for the BIS was 0.67 for DIVAL-, 0.62 for LI-, and 0.25 for PLA-treated patients.

Adolescent↗