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Biomedical subjects

M Buc

Publications and source records attributed to M Buc.

At least 37 records · Page 2Linked to original sources
PubMed1996

Vitiligo is associated with HLA-A2 and HLA-Dw7 in the Slovak populations.

By investigating a group of 67 unrelated adult persons suffering from vitiligo it was found that antigens HLA-A2 and HLA-Dw7 differed in their frequencies in comparison to those observed in the healthy population. The antigen HLA-A2 was found in 76.12% of patients compared to 43.95% in the control group (chi 2 = 25.61, P < 0.005, RR = 4.07). The antigen HLA-Dw7 was present in 56.71% of patients compared to 15.8% in the healthy population (chi 2 = 26.55, P < 0.0001, RR = 6.98). No other significant deviations in the frequencies of investigated antigens were observed.

Adolescent↗
PubMed1996

The immunomodulatory properties of low-molecular tri- and tetrapeptides.

Immunomodulatory effects of six linear tri- or tetrapeptides were studied. These peptides are physiologically inert precursors, which under the action of native proteases split into a C-terminal dipeptide ester, which is subsequently converted by spontaneous intramolecular cyclization to a biologically active compound, i.e., a spirocyclic dipeptide. The following biological activities were evaluated using human lymphocytes: recovery of receptors for sheep red blood cells, test of active E-rosettes, and modulation of T-cell mitogen responses. All tested peptides revealed significant inhibition in some assay, although none of them induced significant inhibition in all assays. The compounds, I, IV, and VI proved to be the best inhibitors in comparison with Alaptide, i.e., cyclo(Ala-Acp).

Concanavalin A↗
PubMed1996

[Immunogenetic mechanisms in autoimmune processes: disorders of immune regulatory mechanisms, genetic determination of autoimmunity, effector mechanisms of autoimmune processes and their therapy].

Autoimmune disease represent a great social and medical problem. 5 to 7% of population suffer from these chronic debilitating disorders. Our knowledge about the immune system and the genetic determination of its components and processes has considerably increased in the fast few years. The purpose of the two articles on autoimmunity published in the previous and this issue is to offer a reader a topical status of the development in this field. Autoantigens, their presentation to T lymphocytes and superantigens were discussed in the first article. The breakdown of regulatory mechanisms of immunity, the genetic basis of autoimmunity, the effector mechanisms responsible for tissue damages and their therapy are reviewed in the presented article. (Tab. 4, Fig. 1.).

Autoimmune Diseases↗
PubMed1995

The role of HLA class II antigens in the induction of cytotoxic T lymphocytes.

Investigation of pairs of unrelated persons mismatched for a particular HLA-DQB1 or -DPB1 gene on the induction of cytotoxic T lymphocytes (CTL) revealed that HLA-DQ and HLA-DP antigens provided a slight proliferative stimulus which was, however, sufficient for the generation of CTL. Monomorphic anti-DQ and anti-DP monoclonal antibodies abrogated the induction of cytotoxic response. The results indicate that the HLA-DQ and HLA-DP antigens play a similar role to HLA-DR specificities in clinical bone marrow transplantation.

Female↗
PubMed1995

Effect of domperidone-induced hyperprolactinemia on selected immune parameters in healthy women.

Domperidone, anti-emetic drug, given to healthy female volunteers, induced an elevation of plasma prolactin (PRL) concentration with the peak in 1-4 h. The release of prolactin had a transient stimulating effect on theophylline sensitive T lymphocytes and on concanavalin A induced mitogenic activity, suggesting an enhanced activity of T suppressor lymphocytes. The relative number of CD4+ lymphocytes decreased markedly one hour after domperidone administration and returned to normal values within 2 h (that means 3 h after taking the drug). The number of lymphocytes positive for dipeptidyl peptidase IV exhibited similar transient increase and normalization of activity. No change was observed in the number of CD8+ lymphocytes. The production of interferon by leukocytes treated with Newcastle disease virus was found to be significantly increased 2 h after domperidone administration. The results suggest that prolactin can selectively stimulate some functions of cellular immunity as well as the release of cytokines (IFN). The present study may contribute to the understanding of the role of the immune system in endogenous hyperprolactinemia.

Adolescent↗
PubMed1994

[NK cell activity and association with the HLA class I antigen complex].

To contribute to the genetic regulation of NK cell cytotoxic activity an association between HLA antigens and a level of cytolysis of target cells (K-562) have been followed. By investigating of NK cell cytotoxic activity in 183 HLA-typed healthy persons it was found that high levels of cytolytic function of NK cells were associated with the antigens of HLA-B8, HLA-B27, HLA-B40, and HLA-B44 as well as the HLA-A2,-B12 phenotypes (in male only). It was also found that low NK cell cytotoxic activity was significantly correlated with homozygosity at HLA loci. These results suggest that HLA genes or genes linked with them may control NK cell cytotoxic functions in man. The authors have also suggested that above mentioned HLA-B antigens might belong to the activating receptor family of NK cells. (Tab. 7, Ref. 48.)

Cytotoxicity, Immunologic↗
PubMed1993

Genetic polymorphism of factor B (Bf) and C3 component of complement in type 1 (insulin-dependent) diabetes mellitus: BFQO allele observed in a diabetic child.

C3 and Bf polymorphisms were studied in 215 and 192 children with type 1 diabetes mellitus (IDDM), respectively. No significant differences in C3 phenotypes and allele frequencies were found between IDDM patients and a healthy population. The rare allele BfF1 was found in 9.37% of diabetic patients but in only 0.35% of the general Slovak population (0.0468 vs. 0.0017). An increased frequency rate of BfSO.7 was also observed in 8.85% of IDDM patients compared with 3.57% of healthy controls (0.0442 vs. 0.0178). The relative risk was 28.83 for BfF1 and 2.55 for BfSO.7. One diabetic child was found to be heterozygous for a silent allele BfQO. This rare Bf allele was transmitted to the boy from his healthy mother.

Adolescent↗
PubMed1993

The major histocompatibility complex in man.

The HLA system is a complex of polymorphic genes divided into a class I group and a class II group. The disclosed tertiary structure of HLA antigens indicates that they are principally involved in binding a variety of self and foreign immunogenic peptides and in their presentation to T cells. Class III HLA region is located between class I and class II regions. It comprises many genes, some of them participate in events of the immune response, too.

Antigen Presentation↗
PubMed1993

The role of HLA-DQ antigens in the induction of cytotoxic T lymphocytes.

Investigating three pairs of HLA-DR (DRB1) identical unrelated persons on the induction of cytotoxic T lymphocytes (CTL) it was found that HLA-DQ antigens provided slight proliferative stimulus which was, however, sufficient for the generation of CTL. The results indicate that the HLA-DQ antigens do play a similar role in clinical bone marrow transplantation as the HLA-DR specificities.

Bone Marrow Transplantation↗
PubMed1993

[Immunogenetics and immunologic aspects of kidney and bone marrow transplantation].

Progress in comprehension of the immunogenetics of the HLA-complex and the discovery of new very potent immunosuppressive agents have enabled organ and tissue transplantations to be performed as a relatively routine therapeutic method. Long-term outcome measured as a half-life in kidney transplantations is 25 years among HLA-identical siblings, 12 years in one haplotype-mismatched paternal donors, and 7 years in cadaver transplantation program. The long-term outcome in the latter group can be markedly improved--to as much as 19 years--when six-antigen program is observed (i.e. donor and recipient are identical in HLA-DR, -B, and -A antigens). The survival of patients after bone marrow transplantation (BMT) having as a donor a HLA-identical sibling has improved remarkably, too. However, only about 30 percent of patients who might benefit from a bone marrow transplant have a genotypically. HLA-identical sibling who could be a donor. Transplants from unrelated donors have become therefore an alternative method. To find HLA-matched donors the establishment of large registries are needed. One of them--Them Bone Marrow Donors Worldwide--in Leiden has over 1.2 million of potential donors at the time being (1992).

Bone Marrow Transplantation↗
PubMed1992

[The HLA complex in 1991].

In November 1990 the Nomenclature Committee of the WHO updated the designation of loci, alleles, and antigens of the HLA complex. Their complete list is presented in our review, along with current knowledge on the complexity of the HLA-D region. Finally, the paper deals with the tertiary structure of HLA antigens discovered in 1987, which has enabled us to understand the biological significance of the HLA complex. (Fig. 5, Tab. 5, Ref. 15.)

HLA Antigens↗
PubMed1991

Reduced expression of HLA-DP antigens on PWM stimulated T lymphocytes in patients suffering from psoriasis vulgaris.

24 psoriasis vulgaris patients were investigated for the expression of class II HLA antigens on the surface of PWM-stimulated T lymphocytes. The percentage of the expression of HLA-DP antigens ranged from 50.1% to 82.6% compared to a 100% level in healthy controls (p less than 0.005). No significant differences in the expression of HLA-DR antigens were observed. A higher frequency of some HLA antigens was found in the group of patients studied: B13 - 23.1%/6.2%, B 17 - 15.4%/7.1%, and Dw7 - 59.4%/15.8%.

Concanavalin A↗
PubMed1990

[Possibilities of finding identical HLA donor-recipient pairs for bone marrow transplantation].

With the aim to detect genotypically identical donors for patients suffering from some type of leukemia or aplastic anemia, HLA antigens and MLC reactivity were determined in 72 families, having together 209 children. HLA identical, MLC negative sibling donors were found for 31 patients, i.e. 43%. Compared to the healthy population, no significant differences were found in the frequency of HLA antigens and haplotypes in 58 leukemic patients. Two recombinations were recorded, one between the loci HLA-A and HLA-B, and the other one between HLA-B and HLA-D/DR. Only 9 persons (2.5%) homozygous for HLA-D antigens were found in the whole series of 353 subjects investigated.

Bone Marrow Transplantation↗
PubMed1990

Occurrence rate of the HLA-identical pair donor-recipient for bone marrow transplantation.

HLA antigens and MLC reactivity were ascertained in 69 families, having altogether 198 children, with the aim to find genotypically identical donors for patients suffering from some type of leukemia or aplastic anemia. HLA identical, MLC negative sibling donors were found for 29 patients, i.e. 42.03%. In 55 leukemic patients the frequency of HLA antigens and haplotypes was calculated. No significant differences were found as compared to the healthy population. One recombination between HLA-A and HLA-B and one between HLA-B and HLA-D/DR loci were observed.

Bone Marrow↗
PubMed1989

[The effect of certain substances on changes in the expression of class II HLA antigens].

With the aid of the RIA method, the authors found that the stimulation of T-lymphocytes by means of PWM lectin is linked to the expressivity of HLA antigens of class II on their surface. A simultaneous addition of indomethacin, tetracycline, coreton, hydrocortisone and novozir was decreasing the expressivity of the Ia antigens and, at the same time inhibited the lymphocyte proliferation. The growth factor for T (IL-2) lymphocytes was increasing the expressivity of HLA-DR antigens in the cells even without a previous stimulation by mitogen. Glucan, serous thymic factor, natrium salicylicum, hippuric acid had no effect on the expressivity of the HLA antigens of class II.

HLA-D Antigens↗
PubMed1989

Family study of natural killer cell activity in C1q-deficient patients with systemic lupus erythematosus-like syndrome: association between impaired natural killer cell function and C1q deficiency.

Impaired natural killer (NK) cell activity has been found in patients with systemic lupus erythematosus (SLE)-like syndrome. The mechanism by which NK cell function is impaired in SLE patients is not quite clear. We report here a family study of NK cell activity in C1q-deficient patients with SLE-like syndrome. In both SLE-active and SLE-inactive stages of the disease, NK cell function was significantly impaired when compared with the healthy controls (10.6 +/- 2.3% and 16.9 +/- 4.8% to 34.7 +/- 9.6%, p less than 0.025). On the other hand, differences in NK cell cytotoxicity between SLE-active and SLE-inactive members of the family were not statistically relevant (p less than 0.1). Further, we found no correlation between NK cell activity and clinical or laboratory values, except for a positive correlation between function of NK cells and C1q and CH50 values, respectively (rs = 0.93, 0.01 less than p less than 0.02). To our knowledge, this is the first report on a notable association between impaired NK cell activity and C1q deficiency. The type of inheritance of C1q deficiency in this family is also discussed.

Adult↗