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At least 1,243 records · Page 69Linked to original sources
PubMed1991

[Electropharmacological test with class-I C drugs in paroxysmal supraventricular re-entrant tachycardia: is a negative result with a drug predictive of the ineffectiveness of other drugs of the same class?].

UNLABELLED: Propafenone and flecainide, both I C class drugs, are first choice in the treatment of paroxysmal supraventricular reciprocating tachycardia. The aim of this study was to check whether a negative or paradoxical electropharmacological test with one of the two drugs was predictive of an equally negative or paradoxical test with the other drug. Thirty patients with disabling paroxysmal supraventricular reciprocating tachycardia, 16 M, 14 F, mean age 30.6 +/- 16 years, were studied with serial electropharmacological tests using esophageal approach. The reentry circuit was sustained by an anomalous pathway in 25 patients (83.5%) whereas it was idionodal in the other 5 (16.5%). Propafenone was tested in 13 patients (43.5%, group A) after flecainide had resulted negative or paradoxical in the first test. In 17 patients (56.5%, group B) flecainide was tested after propafenone had resulted negative or paradoxical. The second drug tested was also ineffective in 14 of the 30 patients (group A + group B) while it had positive results in 16 patients. Specifically, propafenone was positive in 6 of the 13 patients (group A) in whom flecainide had been negative, and flecainide was positive in 10 of the 17 patients (group B) with acute negative or paradoxical propafenone test. These "acute" results were confirmed in steady-state with esophageal study and in the follow-up (21.9 +/- 9.3 months). CONCLUSIONS: 53.5% of the patients who are "non responders" to the electropharmacological test with one of the two drugs (propafenone or flecainide) may be "responders" to the other drug. Thus the ineffectiveness of one of the two drugs is not predictive of ineffectiveness of the other.

Adolescent↗
PubMed1978

Regulation of antibody response in different immunoglobulin classes. IV. Properties and functions of IgE class-specific" suppressor factor(s) released from DNP-mycobacterium-primed T cells.

IgE class-specific suppressor factors (IgE-TsF) released from DNP-Myc-primed T cells showed their suppressor effect in an antigen nonspecific manner, although DNP-specific stimulation was required for their induction. The suppressor activity of IgE-TsF was absorbed with the alloantiserum directed to the subregions between I-A and I-E of the H-2 complex. IgE-TsF from BALB/c mice did not show their suppressor effect on the IgE response of C57BL/6J and vice versa. The suppressor activity of IgE-TsF was removed with a DNP-OA-primed B lymphocyte population including an increased number of IgE-B cells, but not with T cells. Incubation of hapten-primed B cells with IgE-TsF for 3 hr at 37 degrees C selectively abolished the anti-hapten IgE antibody response in the adoptive transfer experiment, indicating that the target cells of IgE-TsF were IgE-B cells.

Animals↗
PubMed1997

HLA class I and class II alleles and haplotypes in Mexican mestizos established from serological typing of 50 families.

We describe new information on the frequency and association of class II antigens (HLA-DR and HLA-DQ) of the major histocompatibility complex (MHC) in Mexicans. The study includes HLA-B typing and its association with the HLA-DR antigens determined in 50 families, which included 100 individuals. This family study allowed the establishment of the precise composition of the 200 HLA haplotypes, which cannot be obtained from unrelated individuals. The predominant antigens in decreasing order of frequency were B35, B39, and B61 at the B locus; DR4, DR5, and DR8 at the DR locus; and DQ3 at the DQ locus. The most common HLA-B,HLA-DR haplotype (considering broad specificities) was B16,DR4, with a frequency of 8.0%. Five HLA-B,HLA-DR haplotypes showed significant delta values (observed vs. expected frequencies) after correcting for the number of comparisons. On the other hand, the most common HLA-DR,HLA-DQ haplotypes were DR4,DQ3 and DR5,DQ3 with a frequency higher than 10%. Ten of the 17 HLA-DR,HLA-DQ haplotypes had significant postcorrection delta values.

Ethnicity↗
PubMed2005

HLA class I and class II frequencies in patients with cutaneous malignant melanoma from southeastern Spain: the role of HLA-C in disease prognosis.

Available data have led to a controversy on the relationship between human leukocyte antigen (HLA) and cutaneous malignant melanoma susceptibility or prognosis. Moreover, the influence of HLA-C on melanoma has not yet been well established. Therefore, the aim of the current study was to analyze the possible influence of the HLA system on melanoma susceptibility and prognosis in the Spanish population. For this purpose, HLA-A and HLA-B serotyping and HLA-C, HLA-DRB1, and HLA-DQB1 genotyping by polymerase chain reactions using sequence-specific oligonucleotide (PCR-SSO) and sequence-specific primer (PCR-SSP) were performed in 174 melanoma patients and 227 ethnically matched controls. The number of controls was increased up to 356 for HLA-C typing. Patients were stratified according to the histological subtypes of melanoma, sentinel lymph node status, tumor thickness, and ulceration of primary lesion. No HLA-A, HLA-B, HLA-DRB1, or HLA-DQB1 relationship with melanoma was observed for susceptibility or disease prognosis. However, the analysis of HLA-C locus showed that individuals homozygous for HLA-C(Lys80) were significantly more frequent within the patient than the control group. Remarkably, individuals homozygous for group 2 HLA-C alleles (HLA-C(Lys80)) seem to be associated with metastatic progression of melanoma. In contrast, we found a negative association between group 1 HLA-C alleles (HLA-C(Asn80)) and disease susceptibility or metastasis development. In conclusion, although an association with HLA-A, HLA-B, HLA-DRB1, or HLA-DQB1 was not demonstrated, the study of the HLA-C locus revealed that the analysis of the dimorphism at position 80 in the alpha1 helix may help to evaluate the risk and prognosis of melanoma in our population.

Case-Control Studies↗
PubMed2002

Association of HLA class I and class II alleles with susceptibility to endometriosis.

Although the exact etiology of endometriosis is unclear, several lines of evidence support roles for both cell-mediated and humoral immunity in its pathogenesis. To assess the association between HLA genotypes and endometriosis, we investigated the frequencies of HLA-A, -B, -C, and -DRB1 antigens or alleles in 123 Japanese patients with endometriosis and 165 healthy women as controls. Significant positive association with endometriosis was observed for HLA-B7 (OR = 2.7, 95% CI = 1.5-5.1, p(u) = 0.0022, p(c) = 0.0440) and for Cw*0702 (OR = 2.1, 95% CI = 1.2-3.3, p(u) = 0.0026, p(c) = 0.0398). An increased frequency of DRB1*0101 was observed in endometriosis patients compared with control subjects (OR = 2.3, 95% CI = 1.2-4.4, p(u) = 0.0143), but was not statistically significant after correction for multiple comparisons. Two-locus analysis indicated that the susceptibility to endometriosis was primarily associated with B7, and that the increased frequencies of Cw*0702 and DRB1*0101 in patients reflected the linkage disequilibrium between B7 and Cw*0702 and DRB1*0101. Most of the B7 antigens were encoded by the B*0702 allele, which was in complete linkage disequilibrium with A24, Cw*0702, and DRB1*0101. Therefore, our results indicated that the HLA-A24-B*0702-Cw*0702-DRB1*0101 haplotype was associated with endometriosis susceptibility. Our findings may provide an important clue to elucidating the pathogenesis of endometriosis.

Adult↗
PubMedDate not supplied

HLA class I and class II frequencies of a Hong Kong Chinese population based on bone marrow donor registry data.

HLA-A, and -B antigen, gene and haplotype frequencies have been calculated from 18,774 southern Chinese donors on a Hong Kong-based bone marrow donor registry. Two hundred and fifty donors were also tested for HLA-DRB1, -DQA1, and -DQB1 alleles using the PCR-SSP technique. Forty-one HLA-A, -B combinations showed statistically significant positive linkage disequilibrium at the 0.05 level after adjustment for the number of haplotypes theoretically possible and 43 showed significant negative disequilibrium. Thirty-nine different DRB1-DQA1-DQB1 haplotypes were identified of which 20 occurred 5 or more times. The most prevalent was DRB1*0901-DQA1*0301-DQB1*0303 (haplotype frequency = 0.1620). This is the first paper to report the distribution of DQA1*0104, DQA1*05011 and DQA1*05012/13 alleles in Chinese. These data are important for phylogenetic, comparative and medico-legal studies and are of particular value in estimating the likelihood of obtaining appropriately matched donors for Chinese patients awaiting bone marrow transplantation.

Bone Marrow Transplantation↗
PubMed2000

Ethanol and halothane differently modulate HLA class I and class II oligomerization. A new look at the mode of action of anesthetic agents through fluorescence spectroscopy.

The field of research considering the working mechanism of anesthetic agents is a complex one and the site or sites of action of general anesthetics are yet to be elucidated. Through the years, on the molecular level, the discussion has shifted from the lipid theories to the more specific interaction with the proteins responsible for the signal transduction. While this approach led to several models, they offer, at best, partial explanations for the observed phenomena. Anesthetic agents interact with many systems, of which the neuronal is best studied, leaving interaction with the immune defense system relatively unexplored. In this study we focus on the interaction of ethanol and halothane with the co-localization on the membrane of HLA I and II molecules. We show that ethanol tends to randomize the distribution of HLA I and II molecules, while halothane increases the clustering of HLA I proteins. The notion that anesthetics modulate cell function by disrupting clustering and thereby promoting a random distribution is a novel approach that may explain the general involvement of many systems during exposition to anesthetic drugs. In this study we show the disturbance of co-localization of molecules that may form a functional network. The relevance of this finding depends on the importance of these networks for extracellular and intracellular processes.

Anesthetics, Inhalation↗