Biomedical subjects

M Bellassoued

Publications and source records attributed to M Bellassoued.

8 recordsLinked to original sources

PubMed2001

Two-carbon homologation of aldehydes via silyl ketene acetals. 2. Study of the stereochemical control in the formation of (E)-alkenoic acids.

The condensation of C,O,O-tris(trimethylsilyl)ketene acetal 1 with aldehydes 2 in the presence of catalytic amounts of mercuric iodide at room temperature affords syn and anti beta-trimethylsiloxy alpha-trimethylsilyl alkanoic acid silyl esters 3 in good yields. These new compounds gave, under acidic or basic conditions, E and (or) Z enoic acids 4. The paths for the formation of these alkenoic acids are discussed.

Journal Article↗

PubMed2001

CTLA-4 gene polymorphisms in Tunisian patients with Graves' disease.

Graves' disease (GD) is an organ-specific autoimmune disorder of multifactorial etiology with a polygenic mode of inheritance. A recent report has demonstrated that there is a linkage and an association between the genetic markers of the CTLA-4 gene on chromosome 2q33 and GD. In order to confirm this association in a Tunisian population, three polymorphisms of the CTLA-4 gene were analyzed: the first is at the -318 position from the ATG start codon consisting of a C/T change; the second is in position 49 of exon 1, which lies in the A/G transition; and the third is in the 3' untranslated region with variant lengths of the dinucleotide (AT)n repeat. The genomic DNA from 144 patients with GD and 205 healthy individuals was genotyped after specific polymerase chain reaction amplification. Comparative analysis using a chi(2) test showed a weak yet significant difference in allele frequencies of the A/G dimorphic marker between patients and controls (P < 0.05), and a significant increase of A/A homozygous individuals among patients (21.53 vs 12.7%, P = 0.02, odds ratio (OR) = 1.89) was found. Analyses of CTLA-4 A/G polymorphism with respect to sex showed a significant difference in A/A genotypes between female patients and controls (OR = 2.14; 95%, 1.13 < OR < 4.04, P < 0.05). The distribution of CTLA-4 (AT)n allele frequencies differed between patients and controls (chi(2) = 38.18, 20 degrees of freedom, P = 0.0084) and the highest OR was found with the CTLA-4 (AT)-224-bp allele (OR = 6.43, 1.7 < OR < 28.64; P = 0.001). In conclusion, these results show that the CTLA-4 gene, or one closely associated with it, confers susceptibility to GD in a Tunisian population.

Abatacept↗

PubMed2001

A full genome screening in a large Tunisian family affected with thyroid autoimmune disorders.

The autoimmune thyroid diseases (AITDs) including Graves' disease (GD) and Hashimoto's thyroiditis (HT) are inherited as complex traits. We initiated a whole genome linkage study of patients with AITD, in order to identify the susceptibility genes involved in their pathogenesis. We studied 39 patients affected with GD or HT and 68 related controls, who belonged to a large consanguinous family composed of more than 200 members. Linkage analysis was performed using the lod score method under two arbitrary models, one dominant and one recessive. A positive lod score was found for D2S171, assuming a recessive mode of inheritance and 50% penetrance, which suggests the presence of a major AITD susceptibility gene on chromosome 2p21. However, no linkage was found with microsatellite markers spanning the HLA system. This locus localised outside MHC will be of interest for investigation of other autoimmune disorders.

Adolescent↗

PubMed2001

[Thyrotoxicosis hepatitis: a case report].

Abnormal liver function in thyroid disorders may be secondary to thyrotoxicosis or to autoimmune injury to the liver. We report the case of a 36-year-old female who developed jaundice and pruritus with mild cholestasis and moderately elevated transaminase levels. The diagnosis of Graves' disease was made shortly thereafter. Laboratory findings were: alanine and aspartate aminotransferase 219 (IU/I (N: 9-50) and 102 IU/I (N: 10-15) respectively, alkaline phosphatase 336 IU/I (N: 40-135), bilirubin 24 micromol/I (N: 2-23), and gamma-glutamyl transpeptidase 232 IU/I (N: 9-43). Abdominal ultrasonography showed normal bile ducts; echocardiography ruled out heart failure; viral and autoimmune markers for hepatitis and cirrhosis were negative. Percutaneous liver biopsy showed moderate intrahepatic steatosis, anisokaryosis, lymphocyte infiltration in the portal areas, and Kupffer cell hyperplasia. Outcome was favorable after seven months of iodine therapy, confirming the diagnosis of thyrotoxicosis hepatitis.

Adult↗

PubMed2001

[Perrault's syndrome: two cases].

Perrault's syndrome is an autosomal recessive ovarian dysgenesis associated with sensorineural deafness. We report two cases in sisters issuing from consanguinous parents. Aged 16 and 21 years, both patients present the two cardinal symptoms of the syndrome. Magnetic resonance imaging in the second sister showed high intensity signals in the periventricular and subcortical white substance and in the central ovale, suggestive of cerebral leucodystrophy. This element may be one of a wide spectrum of neurological symptoms found in Perrault's syndrome. The discovery of the causal genes may allow better understanding of the biomolecular mechanisms involved in gonad and sensorineural differentiation.

Adolescent↗

PubMed2001

[Hemichorea caused by striatal infarct in a young type 1 diabetic patient].

Movement disorders such as chorea and ballism rarely occur in diabetes mellitus. We report the case of 26-year-old man with a 13-year-history of type 1 diabetes mellitus. He presented with a right side hemichorea. Brain CT-scan and MRI showed an infarction of the head of the caudate nucleus and the anterior part of the putamen. Presence of microangiopathy affecting retina, kidneys and peripheral nerves suggest a similar involvement of the lenticulo-striatal arteries. Hemichorea and hemiballism usually occur in older patients presenting type 2 diabetes mellitus. Non-ketotic hyperglycaemia is the common cause in such situation. Striatal infarct, as seen in our patient, is rarely reported.

Adult↗

PubMed2000

Polymorphisms of HLA DQB1 CAR1/CAR2 and TNFalpha IR2/IR4 microsatellite markers in patients affected with Graves disease.

Graves disease is an autoimmune thyroid disorder in which HLA class I and II confer susceptibility in different ethnic groups. An allele-specific polymerase chain reaction was used to characterize the variation of the HLA-DQB1 CAR1/CAR2 and TNFalpha markers located on chromosome 6 in 85 unrelated Tunisian patients affected with Graves disease and 148 healthy control subjects. In contrast to the results regarding TNFalpha alleles showing no difference between patients and controls (P = 0.904), the analysis of the HLA-DQB1 CAR1/CAR2 polymorphism showed a significant difference in its alleles (P < 0.0001). Nevertheless, no allele exhibited a predispositional effect on GD pathogenesis.

Alleles↗

PubMedDate not supplied

[Pure primitive dysautonomia or Bradbury-Eggleston syndrome. Report of 3 cases].

The primary autonomic failure (Bradbury-Eggleston syndrome) is rare. We report three cases (two females and one male) who are 55 year old with orthostatic hypotension, tachycardia, and other signs of dysautonomia. They hadn't a pyramidal, extrapyramidal or cerebellar syndromes. The other causes of postural hypotension are excluded. The autonomic dysfunction was confirmed by autonomic reflex tests and by evaluating of cardiac reflex function; these included heart rate responses to deep breathing and to the valsalva maneuver. Hypotension occurs in a variety of clinical setting; ascertainment of the cause is by non means easy. Primary autonomic failure remains a diagnostic category based on exclusion; its pathophysiology isn't well know and its treatment is only symptomatic.

Autonomic Nervous System Diseases↗