Chemical composition and larvicidal activity of several essential oils from Hypericum species from Tunisia

The chemical composition of the essential oils extracted from some Tunisian Hypericum species and their larvicidal activity against Culex pipiens larvae were evaluated. The chemical compositions of the essential oils from the aerial plant parts were analyzed using gas chromatography–mass spectrometry. One hundred and thirty-four compounds were identified, ranging between 85.1 and 95.4 % of the oil's composition. The components were monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes, non-terpenic hydrocarbons, and others. The larvicidal activity of the essential oils was evaluated using a method recommended by WHO. Larvicidal tests revealed that essential oils from the Hypericum species have a significant larvicidal activity against C. pipiens, with LC₅₀ ranging between 102.82 and 194.70 ppm. The most powerful essential oils against these larvae were Hypericum tomentosum and Hypericum humifusum samples, followed by the essential oil of Hypericum perforatum.     

Effect of Genetic Polymorphism +294T/C in Peroxisome Proliferator-Activated Receptor Delta on the Risk of Ischemic Stroke in a Tunisian Population

PPARδ +294T/C polymorphism was investigated in diabetics, in normolipidemic healthy controls, in dyslipidemic and nondyslipidemic coronary artery disease patients but never in ischemic stroke patients. The aim of this study was to explore, for the first time, the relationship between the genetic polymorphism of PPARδ and the risk of ischemic stroke among patients with diabetes. The study group consisted of 196 patients with ischemic stroke and 192 controls. Plasma concentrations of total cholesterol, triglycerides, low-, and high-density lipoprotein did not differ significantly between subjects carrying the TT genotype and those carrying the CC/TC genotype in both ischemic stroke patients (with or without diabetes) and control groups. The +294C allele (CC + CT genotypes) as compared with TT genotypes was found to be higher in total ischemic stroke patients than in controls. On the other hand, no interaction between diabetes and PPAR +294T/C polymorphism on the risk of ischemic stroke was found (p?=?0.089). The PPARδ +294T/C polymorphism was associated with the risk of ischemic stroke in Tunisian subjects. This polymorphism has no influence on plasma lipoprotein concentrations and body mass index either in healthy subjects or in ischemic stroke patients with or without diabetes both in males and females.     

Neurological manifestations following cured malaria: don't forget post-malaria neurological syndrome

IntroductionCerebral malaria which occurs during the active infection is the most common neurological complication of malaria. Other complications including post-malaria neurological syndrome (PMNS) can rarely occur following complete recovery from the disease. We report a case of post-malaria neurological syndrome in a Tunisian patient.Case presentationA 26-year-old Tunisian man with no past medical history was admitted in 2016 for a muscle weakness of the 4 limbs, seizures, tetraparesis and myoclonus which appeared after he returned from Côte d''Ivoire where he had been treated three weeks ago for Plasmodium falciparum malaria with favorable outcome. Blood smears for malaria were negative. Brain MRI showed multiple hypersignal cerebral lesions. Investigations didn''t show any infectious, metabolic, toxic, vascular or tumoral etiology. Thus, the diagnosis of PMNS was considered. The patient was treated with methylprednisolone with favorable outcome. Two years later, he was completely asymptomatic.ConclusionPMNS should be considered in patients with neurological symptoms occurring within two months of cured acute disease in which blood smears for malaria are negative and other etiologies have been ruled out. In most cases, the disease is self-limited while in severe cases corticosteroid therapy should be prescribed with favorable outcome.     

Limited mutational heterogeneity in the LDLR gene in familial hypercholesterolemia in Tunisia

Familial hypercholesterolemia (FH) is an autosomal dominant disease caused by mutations in the low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), and proprotein convertase subtilisin/kexin type 9 (PCSK9) genes. In previous studies, we have identified novel mutations in Tunisian FH families. In this study, we have extended our investigation to additional families. Five unrelated probands were screened for mutations in the LDLR and APOB genes, using direct sequencing and enzymatic restriction. We identified two novel LDLR mutations: a missense mutation in exon 7: p.Gly343Cys (c.1027G>T), and a nonsense mutation in exon 17: p.Lys816X (c.2446A>T). Using the PolyPhen and SIFT prediction computer programs the p.Gly343Cys is predicted to have a deleterious effect on LDL receptor activity. The missense mutation we found in exon 3, p.Cys89Trp (c.267C>G), has previously been identified in patients from United Kingdom and Spain, and is reported here for the first time in the Tunisian population. Finally, the framshift mutation in exon 10, p.Ser493ArgfsX44, is reported here for the fourth and fifth time in Tunisian families. The latter is the most frequent FH-causing mutation in Tunisia. These LDLR gene mutations enrich the spectrum of mutations causing FH in the Tunisian population. The framshift mutation, p.Ser493ArgfsX44, seems to be a founder mutation in this population.     

Matrix metalloproteinases: a potential therapeutic target in atherosclerosis

Mature human atherosclerotic plaques are frequently characterized by a lipid-rich core covered by a fibrous cap composed of fibrillar collagens, elastin, proteoglycans and smooth muscle cells (SMC). Most sudden deaths due to acute myocardial infarction are caused by rupture of coronary atheroma, leading to a prothrombotic response followed by rapid occlusion of the artery. The accumulation of macrophage-derived foam cells in vulnerable shoulder regions of atherosclerotic plaques correlates with increased local release of matrix-degrading metalloproteinases (MMPs) and weak fibrous cap tissue. These findings suggest a potential role of macrophage-derived MMPs in the weakening and ultimate rupture of plaque structures. Consequently, several studies have focussed on the hypothesis that inhibiting MMP activity would reduce plaque volume and prevent plaque rupture and therefore would be useful in the treatment of atherosclerosis. However, current synthetic MMP inhibitors are not very specific and clinical results have so far been inconclusive. The development of selective inhibitors and focal gene transfer approaches may be better suited for the treatment of atherosclerosis.     

Norplant contraception at the Rabta Tunis maternity hospital

During 1988-1992, physicians used two study protocols to follow 612 women who had accepted the subdermal contraceptive implant Norplant at the Rabta Maternity Hospital of Tunisia. They used WHO criteria to select 375 women aged 18-40 (i.e., healthy women with no contraindications). The remaining 237 women and their infants underwent regular clinical and paraclinical examinations. 58 of these women had heart disease. 13 had diabetes mellitus. 11 women had hypertension. 22 women were breast feeding. The women's mean age was 30. They weighed on average 61 kg. Mean family size was three. 35% and 21% of the women used oral contraceptives or IUDs, respectively, before accepting Norplant. 57% experienced menstrual disturbances after accepting Norplant. 162 women (26.5%) asked for Norplant to be removed. Menstrual disturbances were the reason for removal among 37% of them. This rate was the same for both groups. 1.79% of the women conceived during Norplant use. None of these women had an ectopic pregnancy, however. None of the infants being breast fed had any problems with growth. Norplant appeared to have no adverse effects on lactation. Side effects occurred at the same rate in the healthy women as the women at risk. These findings show that women at risk tolerated Norplant well.     

Inhibition of potato virus Y NIa activity: preparation of monoclonal antibody directed against PVY NI protein that inhibits cleavage of PVY polyprotein

Summary.  A partially purified nuclear inclusion (NI) fraction was obtained from tobacco plants infected by potato virus Y (PVY). Four monoclonal antibodies (MAbs) were produced and characterized using this semipurified fraction as antigen. Data showed that only one was directed against NIa whereas two were directed against cytoplasmic inclusion (CI) protein and the last one against coat protein (CP). These results were due to the fact that the semipurified NI fraction was usually contaminated with CI and CP proteins. When used on in situ immunofluorescence method the anti-NIa MAb showed accumulation of the NIa protein in both nucleus and cytoplasm. In vivo, this MAb was able to detect different forms of the NIa protein including precursors and cleavage products. It was also able to inhibit the cleavage of the polyprotein detected in the semipurified NI. Received October 3, 2000 Accepted, February 15, 2001