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Biomedical subjects

K Boukef

Publications and source records attributed to K Boukef.

At least 19 recordsLinked to original sources
PubMed2001

[Association between type 1 diabetes and polymorphism of the CTLA-4 gene in a Tunisian population].

Susceptibility to type 1 diabetes mellitus is strongly associated with particular HLA class II alleles. However, non HLA genetic factors are likely to be required for the development of disease. The candidate genes include the cytotoxic T lymphocyte associated 4 (CTLA-4) located on chromosome 2q33 and designated (IDDM12), which encodes a cell surface negative signal T molecule providing for activation. We investigated CTLA-4 exon 1 dimorphism in 74 type 1 patients and a control group of 48 healthy subjects from Tunisia using two methods PCR (polymerase chain reaction) allele specific and polymerase chain reaction restriction fragment length polymorphism (PCR RFLP). The CTLA-4/G allele was found on 68.9% in type 1 patients as compared to 51.02% in controls (p = 0.002), mostly in homozygous from 43.24% versus 22.45% (p = 0.0058). This results indicate that CTLA-4/G allele was significantly associated with predisposition to type 1 diabetes in our group from Tunisian population.

Abatacept↗
PubMed2001

Rapid high-performance liquid chromatography analysis for the quantitative determination of oleuropein in Olea europaea leaves.

Olea europaea (Oleaceae) leaves of 14 different cultivars have been studied by a new isocratic HPLC method. Qualitative and quantitative determinations of principal compounds were established for each cultivar. Oleuropein concentration was determined for each sampled tree, using coumarin as internal standard. Bid el Haman, Chemlali, Meski, Cailletier, Tanche, a Verdale-Picholine hybrid, and Lucques, in particular, had high oleuropein concentrations and could be useful sources for industrial extractions.

Antihypertensive Agents↗
PubMed2001

Gene frequencies of human neutrophil antigens in the Tunisian blood donors and Berbers.

Human neutrophil antigens play an important role in provoking immune neutropenia and transfusion-reactions. The aim of this study was to determine granulocyte-specific antigens on the neutrophil Fc gamma receptor IIIb (Fc gamma RIIIb, CD16b), namely, the HNA-1a(NA1) and HNA-1b(NA2) antigens and their gene frequencies in Tunisian blood donors and Berbers. One hundred and ninety-nine unrelated healthy Tunisian blood donors and Berbers were typed for HNA-1a and HNA-1b(NA1 and NA2), using polymerase chain reaction with sequence-specific primers (PCR-SSP). In 24 granulocyte samples, the HNA-1a and HNA-1b phenotypes was additionally determined by the granulocyte immunofluorescence test (GIFT) and correlated with the genotyping results. A subsequent analysis of the genotyping study showed that, the HNA-1a and HNA-1b gene frequencies observed, were 0.342 and 0.658 for Berbers, and 0.311 and 0.668 for blood donors, respectively. In the genotyping study conducted, it was determined that the HNA-1a and HNA-1b gene frequencies observed in Tunisian blood donors and Berbers are similar to those previously reported in other white populations.

Blood Donors↗
PubMed2001

[Autologous transfusion program].

The term autologous transfusion describes transfusion of any blood component that was donated by intended recipient. A recipient who serves as his or her own donor receives the safest possible transfusion in that the risks of transfusion-transmitted infection and alloimmunization are eliminated. A preoperative autologous transfusion program provides many benefits to the donor-patient the blood donor center and the hospital transfusion service; requires a good communication between the transfusion physician and the collecting facility and needs a rigorous technical organization of the blood bank to ovoid the human errors of testing and labeling. Underutilizaton of autologous blood programs in our country is possibly related to a lack of awareness on the part of all the contributors.

Blood Banks↗
PubMed2000

Contribution of flow cytometry to acute leukemia classification in Tunisia.

The precision of immunological characterization of leukemias was improved by a certain number of technical innovations, particularly hybridoma production and standardization, resulting in monoclonal antibodies and definition of recognised cellular antigens (designated by CD: Cluster of Differentiation). The aim of this work was to determine the immunophenotyping profile of patients with leukemia, by means of a flow cytometric method: 66 blood samples coming from leukemic persons in the Sahel region were studied by flow cytometry, using about thirty monoclonal antibodies all marked with a fluorochrome, in one or two colour systems to assess their distribution according to type (lymphoid B or T / myeloid) and age, and to search for possible co-expressions of markers of different lineages. The marked preponderance of childhood B-ALL in our series is, at least partly, attributable to the age distribution of the Tunisian population. In agreement with studies from other countries, the majority of AML cases occurred among adults. A high proportion of AML cases in our series co-expressed markers of other lineages. Overall, accurate classification of acute leukemias was possible from a simple peripheral blood sample in 62 of 66 cases (93.9%).

Acute Disease↗
PubMed2000

NA antigen frequencies in the Tunisian population.

The biallelic NA antigen system is of special interest as the NA antigens are frequent targets of neutrophil antibodies, causing alloimmune neonatal neutropenia, blood transfusion reactions, and chronic benign autoimmune neutropenia in infancy. Neutrophils isolated from the peripheral blood of 119 unrelated individuals at the National Blood Center were phenotyped for NA1 and NA2 using a granulocyte immunofluorescence assay. A subsequent analysis of the phenotyping study showed that the NA1 and NA2 antigen frequencies were 0.529 and 0.865 respectively, and that the estimated NA1 and NA2 gene frequencies were 0.313 and 0.632 respectively. In conclusion, it was determined that the Tunisian population is of Caucasian origin. However, to validate this finding, further investigations are necessary.

Asia↗
PubMed1999

Gene frequencies of human platelet antigens in the Tunisian population.

Gene frequencies for the human platelet antigens HPA-1, -3 and -5 in the Tunisian population were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) on 93 volunteer blood donors (78 were tested for HPA-1, 90 for HPA-3 and 93 for HPA-5). This study shows the highest frequencies of the HPA-1b (0.25) and HPA-5b (0.22) yet recorded. These antigens are considered as markers of a high risk of platelet alloimmunisation in other populations, and for this reason particular attention should be paid in the case of pregnancy or blood transfusion in this population. The 9 base pair deletion located in intron 21 of the GPIIb gene associated with HPA-3b determinant is present in this population. No individual showed the polymorphism associated with HPA-1b (T-->G at codon 40 of the GPIIIa).

Antigens, Human Platelet↗
PubMed1997

Thrombosis in congenital deficiencies of AT III, protein C or protein S: a study of 44 children.

Congenital deficiency in coagulation inhibitors is a cause of hereditary thrombotic disease. The severity of symptoms is variable and depends on the type of deficit. In this paper, 44 children suffering from deep venous thrombosis, with a mean age of 5 years, were studied. A search for Lupus anticoagulant (LA) and coagulation inhibitor deficiency showed: 3/44 cases (6.8%) had protein S deficiency, 2/44 cases (4.5%) had protein C deficiency, 1/44 cases (2.3%) had deficiencies in both protein C and S; no cases of AT III deficiency and LA was positive in 2/44 cases (4.5%). Only 1 case of APC resistance out of 13 studied was found. Four family studies were performed and confirmed the congenital origin of the disorder.

Adolescent↗
PubMed1997

Higher prevalence of parvovirus B19 in Belgian as compared to Tunisian blood donors: differential implications for prevention of transfusional transmission.

Serious anaemia can be induced by human parvovirus B19 (HPV) infection in immuno-compromised patients or subjects with an haemolytic disorder. Routine inactivation procedures are insufficient to neutralize the virus, but screening for HPV is an effective means to avoid transmission by transfusion of blood components. In the present study, we have compared for the first time the IgG and IgM seroprevalence in a North African (Tunisian) and Western European (Belgian) population of blood donors. The prevalence of HPV-specific IgM was less than 2% in both populations, pointing to the absence of an epidemic. The prevalence HPV IgG was significantly (p < 0.01) higher in Belgium (74%) than in Tunisia (65%), without any relationship with age or sex. This finding may suggest a south-north gradient of this infectious disease. Since the presence or absence of HPV-specific antibodies does not preclude transfusional transmission, screening for the virus itself should be done to avoid iatrogenic infection in HPV-naive subjects at risk. In view of the different transfusion policies in Belgium and Tunisia, a strategy for each of both countries is proposed.

Adolescent↗
PubMed1997

[Screening and confirmation of anti-HCV antibodies in Tunisian blood donors].

Antibodies to Hepatitis C virus (HCV) were tested in 43000 Tunisian blood donors by using enzyme immuno-assay. Our results show that 0.7% (304/43000) were anti-HVC positive. Of these 304.78 were confirmed anti-HCV positive (0.18%) by immuno-blot, and 99 displayed an indeterminate profile. Different immune responses were observed: In donors with positive serologic pattern (78/304), 25.6% response towards whole antigens (C + NS3 + NS4 + NS5) was frequently observed (44/78) 56.4%. Reactivity to 2 antigens was observed in 28.2% (22/78) and with 3 antigens in only 15.4% (12/78), with systematic reactivity to core. In donors with indeterminate serologic pattern (99/304) 32.5%, reactivity to non-structural antigen NS5 was the most frequently observed (54/99) 54.5%, reactivity to non-structural NS3 antigen was noted in 27.3% (27/99) and to core antigen in 18.2% (18/99). No donors with isolated reactivity to NS4 were observed in our series.

Adolescent↗
PubMed1995

[Study of class I HLA polymorphism in the Tunisian population].

The HLA class I gene polymorphism (HLA-A, -B) was investigated in a population of 102 Tunisians. Allele and haplotype frequencies as well as linkage disequilibrium between HLA-A and HLA-B loci were calculated and compared with other populations. The most frequent alleles were A2 (23%), A30 (12.5%), A3 (10.2%), A1 (8.5%), A23 (7.4%) for the HLA-A locus and B21 (14.3%), B44 (11.4%), B35 (9.6%), B5 (8.5%) for the HLA-B locus. The most frequent haplotype was A3 B21 (2.6%) and a positive linkage disequilibrium was found for the following allelic associations: A11 B35 (X2 = 6.8), A28 B35 (X2 = 5.3), and A30 B35 (X2 = 5). In conclusion, a specific distribution of HLA class I components in terms of antigen and haplotype frequencies characterizes the Tunisian population. This specific pattern may reflect the great ethnical diversity of this community. All these informations may be helpful in the future for HLA and disease association studies.

Alleles↗
PubMed1995

HLA class II gene polymorphism in Tunisians.

The polymorphism of HLA class II genes (HLA-DRB, DQB, DPB) was investigated in 101 Tunisians using polymerase chain reaction. (PCR) amplification and reverse dot blot (RDB) hybridization. Allele and haplotype frequencies, as well as DRB1-DQB1 linkage disequilibria, were calculated. A total of 26 DRB1 alleles were detected and the most prevalent variant was DRB1*0301 with an allelic frequency at 21.87%. In the DR1 group, DRB1*0102 was most frequent than DRB1*0101. In the DR4 group, DRB1*0403 was the most common allele and was associated with DQB1*0402. Interestingly this DRB1-DQB1 association has not been observed in other populations. With regard to the DR8 group, DRB1*0804 was the unique variant detected, whereas with the DR13 specificity, the most common variant was DRB1*1303 in Algerians also. Although the DQB1 polymorphism analysis showed an allelic distribution very close to that observed in caucasoids, many DRB1-DQB1 associations which have not been reported in studies of other populations, were described. Finally at the DPB1 locus DPB1*1701 and *1301 allele frequencies distinguish clearly this Tunisian sample from a French caucasoïd panel of 83 subjects. In conclusion, a specific distribution of HLA components in terms of gene and haplotype frequencies characterizises this Tunisian population. This specific pattern may reflect the great ethnic diversity of this community. All these informations may be helpful in the future for HLA and disease association studies.

Gene Frequency↗
PubMed1995

[HCV antibodies in hemodialyzed patients in Tunisia].

The prevalence of seropositivity to Hepatitis C and B virus and HIV infection in Haemodialysis patients was assessed in sera from 235 patients from 6 dialysis units in Tunisia. Anti-HCV antibodies were found in 106 patients (45.10%), the hepatitis B surface antigene was found in 19 patients (8%), and no case of HIV infection was found. Anti-HCV positivity was correlated with duration of dialysis (p < 0.001). There was no correlation between anti-HCV positivity and the number of transfusions.

Adult↗