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A Benslimane

Publications and source records attributed to A Benslimane.

At least 55 records · Page 3Linked to original sources
PubMed1995

[Seroprevalence of Chlamydia trachomatis infection in STD consultants in Morocco].

We have conducted a seroepidemiological survey of Chlamydia trachomatis infection among 400 STD consultants in comparison with 400 blood donors. The study was performed by using the indirect microimmunofluorescence technique with Chlamydia trachomatis, Chlamydia psittaci and Chlamydia pneumoniae as antigens. The overall seroprevalences were 60% and 46% for STD consultants and blood donors respectively. The seroprevalences of Chlamydia trachomatis alone were 12.5% for STD consultants and 7.5% for blood donors. No differences were observed according to age in the two groups and people of 20-29 and 30-39 years old, of both sexes were the most concerned. We conclude that Chlamydia trachomatis infection remains an important problem in Morocco.

Adult↗
PubMed1994

Growth inhibition of Trypanosoma cruzi and Leishmania donovani infantum by different snake venoms: preliminary identification of proteins from Cerastes cerastes venom which interact with the parasites.

Venom from three different snake species was tested in vitro against the protozoan parasites Trypanosoma cruzi and Leishmania donovani infantum. Two of them, Cerastes cerastes and Naja haje, exerted a significant growth inhibition of T. cruzi and L. d. infantum parasites. Heating of the venoms abolished their activity, suggesting that the active factors are thermolabile. Incubation of parasites with 125I-labelled C. cerastes venom proteins allowed preliminary identification of components which interact preferentially with the pathogens.

Animals↗
PubMed1993

Characterization of a new leiurotoxin I-like scorpion toxin. PO5 from Androctonus mauretanicus mauretanicus.

Three novel peptide inhibitors of the SKCa channels were purified to homogeneity from the venom of the scorpion Androctonus mauretanicus mauretanicus using one step of RP-HPLC and competition assays with [125I]apamin to rat brain synaptosomes. PO1, PO2 and PO5 have K0.5 of 100, 100 and 0.02 nM, respectively, for the apamin binding site. The sequence of PO5 was established and compared to that of other scorpion toxins active on K+ channels: it contains 31 residues and has a free carboxyl end. it shares sequence similarity with apamin and leiurotoxin I.

Amino Acid Sequence↗
PubMed1993

P05, a new leiurotoxin I-like scorpion toxin: synthesis and structure-activity relationships of the alpha-amidated analog, a ligand of Ca(2+)-activated K+ channels with increased affinity.

The venom of the scorpion Androctonus mauretanicus mauretanicus contains a toxin, P05, which is structurally and functionally similar to scorpion leiurotoxin I (87% sequence identity), a blocker of the apamin-sensitive Ca(2+)-activated K+ channels. It is a 31-residue polypeptide cross-linked by three disulfide bridges. A C-terminal carboxyl-amidated analog of P05 (sP05-NH2) was chemically synthesized by the solid-phase technique and fully characterized. Toxicity assays in vivo established that sP05-NH2, like native P05, is a potent and lethal neurotoxic agent in mice (LD50 of 20 ng per mouse). Pharmacological assays in vitro however showed that, unlike P05 which has a binding affinity of 2 x 10(-11) M, sP05-NH2 apparently binds irreversibly to the apamin receptor. Iodination at the C-terminal His gave diiodo-sP05-NH2, which had a binding affinity similar to that of native P05. The disulfide bridge pairings were chemically determined for sP05-NH2 and thereby deduced for P05 and leiurotoxin I: linkages were between Cys3 and Cys21, Cys8 and Cys26, and Cys12 and Cys28. Molecular dynamics refinement of P05 also using data from leiurotoxin I suggests that P05 is mainly composed of a double-stranded, antiparallel beta-sheet (from Leu18 to Val29) linked to an alpha-helix (from Arg6 to Gly16) by two disulfides (Cys8-Cys26 and Cys12-Cys28) and to an extended fragment (from Thr1 to Leu5) by the third disulfide (Cys3-Cys21). In agreement with the model, circular dichroism analysis of sP05-NH2 showed that the toxin structure is highly rigid.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

MHC-I non-restricted cytotoxic activity in Macaca sylvana experimentally inoculated with HIV2 and SIV/mac.

The anti-retrovirus cell-mediated immunity was repeatedly investigated in seven monkeys (Macaca sylvana). Four of these animals were injected with cell-free supernatants containing human immunodeficiency viruses: two monkeys received HIV1 Bru (2.5 x 10(6) cpm), two received HIV2 Rod (1.5 x 10(6) cpm). Two additional animals were injected with a cell-free supernatant containing simian immunodeficiency virus SIV/mac 251 (1.5 x 10(6) cpm) and the last animal served as control. The four macaques infected with HIV2 Rod and SIV/mac 251 seroconverted. Freshly isolated and non stimulated peripheral blood mononuclear cells from these infected macaques and from the uninfected control were repeatedly assessed for cytolytic activity. Target cells consisted of heterologous human cell lines expressing HIV1 Bru, HIV2 Rod or SIV/mac proteins. A significant cytotoxic activity, non-restricted at the major histocompatibility complex class I (MHC-I), was demonstrated in one HIV2 Rod-infected animal (F8) and in one SIV/mac 251-infected animal (M1). This last animal showed progressively diminishing cytolytic activity that was correlated with a pronounced decrease in CD4+ lymphocytes. An AIDS-like disease developed in M1, with presence of lymphadenopathy, weight loss, diarrhea and opportunistic infections. Cytotoxic activity was active against SIV and HIV2-infected target cells in an MHC-unrestricted manner; it was specific to virus-infected cells and there was cross-reactivity between HIV2 and SIV. Cytotoxic effectors appeared to be mainly CD8+ cells. This model may prove to be very useful in evaluating the capacity of candidate AIDS vaccines to elicit effective cell-mediated immune responses.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Kaliotoxin, a novel peptidyl inhibitor of neuronal BK-type Ca(2+)-activated K+ channels characterized from Androctonus mauretanicus mauretanicus venom.

A peptidyl inhibitor of the high conductance Ca(2+)-activated K+ channels (KCa) has been purified to homogeneity from the venom of the scorpion Androctonus mauretanicus mauretanicus. The peptide has been named kaliotoxin (KTX). It is a single 4-kDa polypeptide chain. Its complete amino acid sequence has been determined. KTX displays sequence homology with other scorpion-derived inhibitors of Ca(2+)-activated or voltage-gated K+ channels: 44% homology with charybdotoxin (CTX), 52% with noxiustoxin (NTX), and 44% with iberiotoxin (IbTX). Electrophysiological experiments performed in identified nerve cells from the mollusc Helix pomatia showed that KTX specifically suppressed the whole cell Ca(2+)-activated K+ current. KTX had no detectable effects on voltage-gated K+ current (delayed rectifier and fast transient A current) or on L-type Ca2+ currents. KTX interacts in a one-to-one way with KCa channels with a Kd of 20 nM. Single channel experiments were performed on high conductance KCa channels excised from the above Helix neurons and from rabbit coeliac ganglia sympathetic neurons. KTX acted exclusively at the outer face of the channel. KTX applied on excised outside-out KCa channels induced a transient period of fast-flicker block followed by a persistent channel blockade. The KTX-induced block was not voltage-dependent which suggests differences in the blockade of KCa channels by KTX and by CTX. Comparison of KTX and CTX sequences leads to the identification of a short amino acid sequence (26-33) which may be implicated in the toxin-channel interaction. KTX therefore appears to be a useful tool for elucidating the molecular pharmacology of the high conductance Ca(2+)-activated K+ channel.

Amino Acid Sequence↗
PubMed1992

Establishment of T-lymphoid cell lines from Morroccan patients with tropical spastic paraparesis.

Two T-cell lines were established from peripheral blood mononuclear cells of two Moroccan patients with tropical spastic paraparesis and then named PR52 and PR144. The two cell lines showed a T lineage of activated CD4+ with high density of Tac+ (IL2 receptor). No expression of CD8 was observed. The virus particles were detected by reverse transcriptase activity and the viral antigens were also detected by immunofluorescence (IF) and Western blot. After six months of culture greater than 90% of the cells exhibited HTLVI antigen by IF. Lysate virus particles on Western blot analysis revealed p19,p24, and p53 gag protein similar to those detected in C91/PL virus particles from an adult T-cell leukemia (ATL) patient. gp46 and gp61 were also weakly detected. These two T-cell lines established will serve as substrate for further comparative studies on TSP and ATL isolates.

Base Sequence↗
PubMed1991

Analysis by high-performance liquid chromatography of Androctonus mauretanicus mauretanicus (black scorpion) venom.

The venom of the black scorpion, Androctonus mauretanicus mauretanicus, was obtained by means of manual stimulation and was analyzed using high-performance liquid chromatography. Starting from 20 mg of venom and using only two chromatographic steps, six toxins were purified to homogeneity. They have been characterized by their amino acid content and compared to those already isolated from a pool of venoms obtained using electric stimulation (Rosso and Rochat, Toxicon 23, 113-125, 1985). The toxins Amm I and Amm II were not found, suggesting either different levels of toxin expression or the existence of Androctonus mauretanicus mauretanicus subspecies. Using rat brain synaptosomes, it was demonstrated that the toxins Amm III, Amm IV and Amm V were alpha-toxins. The toxin Amm VI was neither alpha- or beta-toxin. Unexpectedly, the toxin Amm VII was found to be a beta-toxin, the first one identified in a north African scorpion venom. In addition, some toxins active on mammals exhibited different levels of specificity towards phylogenetically related groups of arthropods.

Amino Acids↗
PubMed1989

[T lymphocytes in the circulating blood and pleural fluid of patients with tuberculosis or cancer].

Inflammatory pleurisies in the adult are particularly rich in CD4 lymphocytes, capable of inducing and facilitating the immune reaction. The aim of this study was to determine the percentage of CD4 and CD8 lymphocytes in pleural fluid and blood in 13 patients with tuberculous pleurisy and 12 patients with pleural neoplasms, to establish the diagnostic value of this analysis. Independent of the etiology of the effusion there is a concentration of CD4 T lymphocytes in the pleural fluid compared to the blood (49.52 +/- 12.36% and 39.28 +/- 6.74%, respectively, p value less than 0.001). However, there was a similar concentration for the two types of disorders studied with 59.92 +/- 7.26% for tuberculous pleurisies and 45.83 +/- 6.26% for neoplastic effusions, thus this technique does not make the diagnostic orientation any clearer.

Adult↗
PubMed1988

[Evaluation of a fast test for direct research on streptococcal group A from pharyngeal samples].

Importance of streptococcal pharyngitis rapid diagnosis is increasing. 645 patients with pharyngoamygdalitis were tested. The correlation between bacteriologic culture and rapid test is 86%, the sensibility of the test is 68%, its specificity is 92%, while the predictive positive and negative values are 75% and 90%. These results show the interest of the rapid test for the diagnosis of streptococcal pharyngitis.

Adolescent↗
PubMed1987

Multicentre evaluation of a direct coagglutination test for group A streptococci.

A coagglutination test for detection of group A streptococci in throat samples was evaluated in a multicentre study and found to be about 95% sensitive when applied to swabs taken from symptomatic patients which yielded more than 100 colonies per plate on culture. The sensitivity of the test dropped significantly when it was applied to swabs giving fewer than 100 colonies on culture. The specificity of the test was high regardless of colony count on conventional media.

Acute Disease↗
PubMed1986

Streptococcal group A polysaccharide antibodies assayed by an ELISA determination of antibodies in rabbit hyperimmune sera; normal levels in man and comparison with levels in patients with rheumatic fever and with poststreptococcal glomerulonephritis.

An enzyme-linked immunosorbent assay (ELISA) was adapted to measure antibodies to streptococcal group A polysaccharide. The components of the reaction were studied, including the concentration of the polysaccharide antigen, the suppression of non-specific reactions, optimal conjugate binding conditions and the most suitable plates. The specificity of this test was documented by studies using immune sera and polysaccharide antigens of various groups of beta-hemolytic streptococci. In addition dynamics of the antibody response in animals as well as in man were investigated. The upper limit of normal level of this antibody in normal healthy persons was determined by this technique. We found that 80% of patients with rheumatic fever and acute glomerulonephritis showed an elevation of the group A polysaccharide antibody titer. Determination of this antibody response by the ELISA technique is clinically useful in evaluation patients with the nonsuppurative sequelae of group A streptococcal infections.

Adolescent↗
PubMedDate not supplied

Anti-HCV seroprevalence and risk factors of hepatitis C virus infection in Moroccan population groups.

Hepatitis C virus (HCV) seroprevalence and transmission routes were investigated in several groups of the Moroccan population. This study showed a low HCV seroprevalence in the Moroccan general population. However, haemodialysis patients and haemophiliacs were at higher risk of having HCV infection, since the prevalences were, respectively, 35.1 and 42.4% in comparison with the blood donors' prevalence (1.1%). These results indicated that parenteral exposure is the transmission pathway of HCV. To investigate the possibility of vertical HCV transmission, a cohort of healthy, unselected pregnant women were included in the study. A prevalence of 1% was found among them. Seven newborns were anti-HCV-positive, although, when RT-PCR was used to search for HCV RNA in their sera, none of them was viraemic. These data indicated that anti-HCV antibodies were passively acquired in these cases. We concluded that vertical transmission is absent when mothers are at low risk of contracting other parenterally or sexually transmitted diseases. Three percent of a group of patients of a centre for sexually transmitted diseases were repeatedly anti-HCV-positive, suggesting the possible sexual transmission of HCV. When screening 116 sera of anti-HIV-positive subjects, 19.8% were anti-HCV-positive. Furthermore, 17.9% of the sixty-seven patients who were proven to have sexually contracted HIV were also anti-HCV-positive. These data might reflect a likely cotransmission of these two viruses, hence suggesting HIV is a cofacter for HCV sexual transmission, as previously reported.

Adolescent↗
PubMedDate not supplied

Pre-core mutation associated with lack of hepatitis B e antigenaemia in Moroccan asymptomatic carriers of the virus.

Recently, ongoing chronic liver disease with persistent viraemia has been described in hepatitis B virus (HBV) carriers despite the presence of anti-HBe. This has been attributed to infection with pre-C-region-mutated HBV variants. To investigate the possible existence and the prevalence of HBV variants in Morocco and the correlation between HBV DNA detection by polymerase chain reaction and pre-S1 antigenaemia, we tested twenty blood donors, HBsAg chronic carriers for more than one year. The diagnosis of such HBeAg-negative HBV variants was determined by a previously described rapid detection method using selective oligonucleotide hybridization. Probes M0, M1 and M2 correspond, respectively, to a non-mutated distal pre-C sequence, a one-point-mutated sequence with a TAG stop codon at pre-C codon 28 and a two-point-mutated sequence with codon 28 TAG and codon 29 GAC. All the 5 HBeAg-positive samples hybridized with the M0 wild-type probe only. Among the anti-HBe-positive samples, one hybridized with the M0 probe only, whereas another hybridized with none of the oligoprobes. The 13 remaining HBeAg-negative cases hybridized with the M1, M2 or combined M0, M1 and M2 probes. Seven of the 13 HBeAg-negative samples hybridized with more than one probe. DNA sequencing confirmed mixed distal pre-C sequence changes in samples hybridizing with more than one probe. These data demonstrate the existence, in patients, of HBV variants containing an inactive pre-C region and hence the incapacity to synthesize pre-C-region-derived HBeAg.

Base Sequence↗