PubMed Health⌕ Search

Biomedical subjects

M Souissi

Publications and source records attributed to M Souissi.

At least 19 recordsLinked to original sources
PubMed2006

Apolipoprotein B signal peptide polymorphism: distribution and influence on lipid parameters in Tunisian population.

Apolipoprotein B (apo B) is the major protein component of LDL, VLDL and chylomicrons. Numerous polymorphisms of the apolipoprotein B gene have been described. Particularly, the insertion/deletion polymorphism located in the coding part of the signal peptide of apo B, associated with modification of lipid concentrations and the risk of cardiovascular disease, has been reported in the general population. No such study in the Tunisian population has been performed. The aim of our study was to assess the effect of insertion/deletion polymorphism of the apolipoprotein B gene on lipid levels in a sample of the Tunisian population. A total of 458 unrelated subjects (321 men and 137 women) were included. The insertion/deletion polymorphism was determined by electrophoresis on polyacrylamide gels after PCR amplification. The relative frequencies of the Ins and Del alleles were 0.74 and 0.26, respectively. These frequencies were similar to those found in other Caucasian populations. There was no significant difference in serum TC, TG, and HDL-C levels due to the influence of the genotypes. However, significant variation among the three genotypes was seen for LDL-cholesterol (p<0.001) and apo B (p<0.001) levels. Individuals homozygous for the Del allele had higher levels than individuals homozygous for the Ins allele, while individuals heterozygous for both alleles exhibited intermediate levels. When the data were analyzed in men and women separately, a similar effect was seen in both groups. Our results show that distribution of apo B insertion/deletion polymorphism in Tunisians is similar to other Caucasian population and confirm the reported association with serum LDL-cholesterol and apo B concentrations.

Adult↗
PubMed2006

Apolipoprotein E polymorphism in the Tunisian population: frequency and effect on lipid parameters.

OBJECTIVES: We determined the frequencies of apolipoprotein E (apo E) gene alleles and examined the association between apo E polymorphism and lipid parameters in a sample of the Tunisian population. DESIGN AND METHODS: Apo E polymorphism was investigated using PCR, and plasma lipid parameters were measured in 122 men and 111 women aged 35 to 87 years. RESULTS: The allele frequencies were epsilon2: 7.3%, epsilon3: 84.6%, and epsilon4: 8.1%. Apo E polymorphism was associated with significant differences (P<0.001) in total cholesterol, apo B and LDL cholesterol in both men and women. epsilon2 carriers had the lowest mean total cholesterol, apo B and LDL-C concentrations, and subjects with the epsilon4 allele had the highest levels. Triglycerides levels increased with the epsilon4 allele, but this did not reach statistical significance. These results remained unchanged after adjustment for age, body mass index, sex, hypertension, diabetes and smoking. However, in obese subjects (BMI>30 kg/m2), TG concentrations were significantly lower in individuals homozygous for the epsilon3 allele compared to those with the alleles epsilon2 or epsilon4. CONCLUSION: In this sample of the Tunisian population, the distribution of apo E gene alleles is similar to that observed in Southern European populations with low prevalence of the epsilon4 allele. Variations in the apo E gene play a role in determining plasma lipid levels. These data also suggest that effects of apo E alleles on lipids levels are partly dependent on environmental variables such as BMI. These findings highlight the importance of the gene/environment interaction on the deleterious effect of obesity on cardiovascular risk factors.

Adult↗
PubMed2006

[Homocysteinemia and coronary artery disease: a case-control study in a Tunisian population].

We have determined the prevalence of hyperhomocysteinemia and tested its relationship with coronary heart disease in Tunisian patients. The study included 70 angiogrphically proven coronary patients and 140 age- and sex-matched healthy subjects. Plasma homocysteine folate and vitamin B12 were analyzed by immunoenzymatic methods. Hyperhomocysteinemia was considered for plasma homocysteine concentration >17 micromol/L. Mean plasma homocysteine concentration and hyperhomocysteinemia prevalence were significantly (p<0.001) higher in patients (16.3 +/- 7.9 micromol/L and 29%) than controls (12.6 +/- 4.0 micromol/L and 10%). The association between hyperhomocysteinemia and coronary heart disease persisted after adjusting on main cardiovascular risk factors (multi adjusted odds ratio, 2.99; 95% CI, 1.18-7.59; p=0.02). No association was observed between hyperhomocysteinemia and coronary disease severity and extent. This study showed an independent association between hyperhomocysteinemia and coronary heart disease, suggesting a role of hyperhomocysteinemia in atherothrombogenesis. However, causal relationship is not yet established. Until results of homocysteine-lowering therapy trials become available, hyperhomocysteinemia should be researched and treated in coronary heart disease patients.

Case-Control Studies↗
PubMed2001

[Vitamin E: structure, metabolism, and functions].

Vitamin E is a generic term denoting eight different isomers among which alpha-tocopherol is the most important and most active. Vitamin E metabolism is closely linked to lipids during intestinal absorption, plasma secretion and transport, and tissue uptake. It is a key compound involved in many physiological processes, such as neurological and immune functions. The most common role of vitamin E is its antioxidant effect, protecting molecules and tissues against the deleterious effect of free radicals. Vitamin E also contributes to the stabilization of biological membranes. In addition, it intervenes in the regulation of several enzymes and probably has impact on gene expression. Advancing knowledge about vitamin E has been achieved with high performance liquid chromatography, making assay accessible to many laboratories, and the use of deuterated derivatives to better apprehend its metabolism. Certain issues remain unresolved concerning the molecular basis of vitamin E's mechanism of action and the exact nature of metabolic dysfunction leading to the clinical manifestations of severe vitamin E deficiency.

Humans↗
PubMed2001

[Vitamin E deficiency. Etiopathogenesis, clinical, histopathologic, and electrical features, and main etiologies].

Vitamin E deficiency is frequently observed in human pathology. In most cases, deficiency is moderate and asymptomatic. Severe deficiency is rare and presents as a progressive neurological syndrome including cerebellar ataxia and posterior cord injury. Neuropathological and electrophysiological features confirm spinocerebellar degeneration. The pathophysiology of vitamin E deficiency nervous dysfunction is still unknown. Oxidative alterations due to the lack of the main lipid-soluble antioxidant could be involved. A few causes of vitamin E deficiency are recognized (malnutrition, impaired lipid absorption, specific anomaly of hepatic or intestinal secretion of vitamin E, excessive endogenous consumption), but diseases associated with vitamin E deficiency are numerous and divers. Symptomatic severe deficiency is constantly observed in ataxia with vitamin E deficiency and abetalipoproteinemia. Intestinal, hepatobiliary, and pancreatic diseases are often associated with more or less marked deficiency. Other pathological circumstances such as malnutrition, alcoholism, hemolytic anemia, renal failure and hemodialysis could be associated with moderated and asymptomatic vitamin E deficiency. Oral or regular administration of high-dose vitamin E is required for patients with symptomatic severe deficiency. An adapted supplementation is recommended for patients with a marginal vitamin E status.

Electrophysiology↗
PubMed2001

[Vitamin E deficiency: risk factor in human disease?].

Oxidative stress is suspected to intervene in certain chronic diseases. Much research has been devoted to the relationship between vitamin E, a major lipid-soluble antioxidant, and certain widespread diseases. Experimental and epidemiological proof supports a protective effect of vitamin E in a number of pathological processes such as coronary heart disease, cancer, cataract, diabetes mellitus, and Alzheimer disease. Randomized clinical trials have not confirmed a beneficial effect of vitamin E supplementation on the progression of these diseases. Certain methodological biases could however have affected these studies, explaining conflicting results. These biases include inaccuracy of vitamin E intake estimates and changes in eating habits during the course of the survey. An insufficient supplementation period using an insufficient dose and inclusion of aged and high-risk patients are the main limitations of the reported clinical trials. Large scale randomized clinical trials including healthy and low-risk subjects, along with prolonged administration of high-dose natural vitamin E, associated with synergetic compounds, and testing on morphological or biological features, will allow a better understanding of the relationship between vitamin E and chronic diseases.

Cardiovascular Diseases↗
PubMed2000

Vitamin E and coronary heart disease in Tunisians.

BACKGROUND: Vitamin E (VE) is thought to be effective in preventing atherosclerosis. However, to date no consistent relationship has been identified between VE and coronary heart disease (CHD). This study was designed to assess the degree of association between VE and CHD in a sample of the Tunisian population. METHODS: Sixty-two angiographically confirmed coronary atherosclerotic patients and 65 age- and sex-matched controls were included. VE was measured in plasma and in the LDL fraction by HPLC. Cholesterol, triglycerides, and phospholipids were measured by enzymatic methods. RESULTS: A trend toward a meaningful decrease of plasma VE was observed in affected patients compared with controls (P: = 0.06). VE concentrations standardized for cholesterol and lipid concentrations were significantly lower (P: <0.02) in coronary patients than in controls (4.35 +/- 1.03 vs 4.82 +/- 1.23 mmol/mol for cholesterol-adjusted VE and 2.35 +/- 0.56 vs 2.66 +/- 0.65 mmol/mol for lipid-adjusted VE, respectively). In the LDL fraction, only cholesterol-standardized VE was significantly lower in cases than controls (3.84 +/- 1.13 vs 4.41 +/- 1.16 mmol/mol). This association between VE and CHD remained unchanged independent of age, sex, smoking habit, hypertension, and diabetes. In CHD patients, lower lipid-adjusted VE was associated with enhanced LDL susceptibility to oxidation but without alteration of the serum fatty acid profile. CONCLUSIONS: These results support the hypothesis that VE plays a role in preventing atherosclerosis.

Adult↗
PubMed1995

[Determinant factors in the choice of site of delivery and the role of peripheral maternity units in a semi-urban environment in Tunisia].

The authors analyse, in the context of a developing country, a number of factors which can determine the choice of site of delivery in a population with access to several possibilities. The role of peripheral (or local) maternity units is considered in particular, in view of the utilisation problems which they raise. This leads to the conclusion of a degree of irrationality in the choice of health care services and the characteristics of women interacting with those of professionals when explaining the choice of site of delivery. Better management of available services is desirable in order to render peripheral maternity units more useful, and improve the medical performance at the time of delivery. Sensitization of the public and above all of health professionals nevertheless remains essential.

Delivery, Obstetric↗
PubMed1994

[Positioning of hemodialysis catheters after locating the internal jugular vein by echo-Doppler].

Despite significant progress, vascular access remains a major concern for nephrologists. For the last 6 years we have used as temporary vascular access silastic twin catheters implanted into the internal jugular vein based on Canaud's method. We have developed in 15 patients an ultrasound-guided method using an ultrasonic Doppler to improve access to the internal jugular vein, prior to its catheterization. Ultrasound assistance was provided by a 5MHz mechanical sectorscanning transducer (Toshiba 270A). The internal jugular vein and carotid artery were visualized. The skin overlying the internal jugular vein was marked with indelebile ink. The internal jugular vein was cannulated successfully in 14 patients. The use of ultrasound guidance to cannulate the internal jugular vein improves success, and reduces complications. This method is recommended in patients with distorted cervical or subclavicular anatomic characteristics, or with bleeding tendency.

Catheterization, Central Venous↗
PubMed1994

[Femoral arteriovenous fistulas after vascular puncture for hemodialysis].

From 1978 to 1991 we observed 10 patients who developed femoral arteriovenous fistula after venous puncture for hemodialysis. The fistula most often appeared after several punctures, but 3 developed after a single puncture. Diagnosis was made on the basis of local observation and auscultation of the vessel (bruit + thrill n = 10, hematoma n = 4, pulsatile mass n = 1). Two patients had arteriography and 2 had echo-doppler. Arteriography was not required for diagnosis (since clinical signs were sufficient), or for treatment, since echo-doppler and surgery indicated the location of the fistula. Five patients underwent surgery. In all cases, continuity of the main vessels of the lower member was maintained or reestablished during surgery. Surgery is mandatory for high flow rate. Such fistulas cannot be used and can cause cardiac failure in patient with another fistula for hemodialysis. Surgery should not be undertaken too early because of the possibility of spontaneous clotting (particularity if echo-doppler shows low flow rate), and to allow organization of the lesions and easier dissection. Auscultation of the vessel should be a routine procedure after any femoral vein puncture in order that this complication not be overlooked.

Adult↗
PubMed1994

[Tunneled double femoral catheters: emergency vascular access for hemodialysis].

Transient vascular access for hemodialysis is a daily problem in nephrology. Internal jugular twin catheters using Canaud's technique is the method of reference, which we have applied since 1987. In 3 cases where the internal jugular route was impraticable, twin catheters via the femoral route were used. The catheter was placed by percutaneous route, at the bedside, in rigorous aseptic conditions and with local anesthesia. The catheter emerge at mid-thigh. Mean placement time was 45 mn. The ideal site for distal end of the catheters is in the inferior vena cava. No traumatic complication occurred during placement. No infectious episode was observed. All the catheters that were removed were sterile in culture. No thrombosis of femoral, iliac or inferior cava veins were observed by echodoppler after removal of the catheters. In conclusion, twin femoral catheters are a good alternative when jugular access is impossible or contraindicated.

Adult↗
PubMed1993

[Radiological exploration of hematuria].

Hematuria is defined as the presence of blood in urine. Its site of origin can be in any point of the urinary tract. Its discovery leads to clinical, biological and radiological investigations. The causes of hematuria are dominated, in terms of frequency, by urinary infection and lithiasis. The risk of associated lesions, especially of a tumor, must lead to regarding them as excluding diagnoses. Besides the so-called "medical" hematurias of glomerular origin (hematuria with proteinuria and cylinder casts) and hematurias occurring during a first episode of cystitis in women, the radiological exploration of "surgical" hematuria is systematic and always begins with an IVP. When the IVP is normal, a cystoscopy is most often made. The other radiological examinations (CT, Doppler ultrasound) are performed only according to the findings of IVP and cystoscopy. Arteriography combined with renal phlebography is indicated if the assessment is negative in case of recurrent hematuria or of massive hematuria. It is mainly aimed at detecting a vascular malformation. When this exploration is completed, an etiology is found is about 90% of all cases.

Female↗
PubMed1993

[Renal Doppler ultrasonography in the diagnosis of acute obstructions of the upper urinary tract].

A comparative study of the resistivity indices (RI) obtained in both kidneys has been carried out in 30 controls and 60 patients with suspected unilateral acute obstruction of the upper urinary tract. Doppler findings (difference in the mean RI of both kidneys, delta RI) in the pathologic population have been systematically correlated to the data yielded by intravenous pyelography (IVP). In the control population delta RI was always < or = 0.03 (mean delta RI = 0.01, SD = 0.01). Considering that an increase in delta RI > or = 0.05 (> mean RI + 3 SD) is significant, 93% sensitivity and 100% specificity are obtained for the diagnosis of unilateral acute obstruction. Comparison of the resistivity indices of both kidneys is more specific and more sensitive than the assessment of the index on the obstructed side only; it improves the performance of ultrasonography in the initial diagnosis of acute urinary tract obstruction.

Acute Kidney Injury↗
PubMed1993

[Role of MRI in the diagnosis of kidney cancer].

The recent technical developments in magnetic resonance imaging (MRI) and the use of paramagnetic contrast media (gadolinium compounds) have considerably improved the performances of MRI for the detection and characterization of renal tumors. MRI does not have specific merits for the diagnosis of the typical form of cancer, nor for the detection of small kidney tumors, both being mainly based on computed tomography (CT). On the other hand, it can be used for the diagnosis of atypical forms of cancers (small, hypovascular, cystic or hemorrhagic cancers) which raise problems of differential diagnosis with some pseudotumoral lesions, complex cysts and benign tumors. Its complementarity to CT for the characterization of an atypical mass results from the signal information it provides, from a better contrast resolution, and from the possibility to make sections in all planes of space. Except for angiomyolipoma, which has a fatty content, there is no really specific MR criterion as present to evidence benign renal tumors. Concerning regional extension, CT remains the primary technique of choice, as it allows studying the limits of the tumor, the renal compartment ans its walls, the renal vein and the inferior vena cava, the neighboring organs and the contralateral kidney all together. Its findings allow defining the indications of MRI, which, as a complementary exploration, is often decisive to assess venous invasion.

Diagnosis, Differential↗
PubMed1993

[HELLP syndrome. Epidemiological, nosological and prognostic aspects].

The authors report a prospective and controlled study of hellp syndrome in two groups of patients: normal and preeclamptic. Hellp syndrome was seen only in the pre-eclamptic group (19.3 per cent). Maternal prognosis was poor when Hellp syndrome was confirmed. Several maternal complications were seen: severe hypertension, subarachnoid hemorrhage, coagulation disorders and renal failure. Maternal mortality was high (16.7 per cent). Hellp syndrome does not worsen fetal prognosis, which is already compromised by pre-eclampsia.

Adult↗
PubMed1992

[Imaging of renal cancer in adults].

In its typical form renal carcinoma shows at imaging as a solid, heterogeneous and vascularized mass deforming the kidney; its CT scan appearance is usually very suggestive. Atypical forms (small or cystic carcinomas, large carcinomas with exorenal extension, haemorrhagic carcinomas) mainly raise problems of characterization; the lesional image is always suspicious at CT or combined US, CT and MRI examinations. The detection of small tumours primarily rests on CT with contrast injection, a technique which is more sensitive (94%) than all other techniques. Among non-tumoral lesions which may look like renal carcinomas, some pseudotumoral inflammatory lesions and suspicious atypical cysts often require histological examination. With the exception of angiomyolipoma with its fat content detectable at CT or MRI, there is no truly specific criterion to differentiate benign tumour from cancer. The diagnosis of renal carcinoma extension primarily rests on MRI. In a number of cases the results are so inadequate for the study of renal veins and caval vein that a complementary exploration of these veins by Doppler ultrasonography or MRI must be requested.

Adult↗