The significance of gastric helicobacteriosis in the genesis hemorrhage from duodenal peptic ulcer

Based on a comprehensive analysis of findings from examination and surgical treatment of 196 patients with bleeding pyloroduodenal ulcers, it was found out that patients with concurrent helicobacteriosis of the stomach are prone to more unfavourable course of their illness, which fact is evidenced by a greater loss of blood and higher risk for bleeding recurrences. A classification is proposed by the authors, taking advantage of the data from endoscopic, microscopic and immunoenzymatic techniques, with the purpose of providing an assessment of degree of severity of helicobacteriosis of the stomach.     

Immune recognition of viral antigens

The response exhibited by the immune system to viral and other foreign antigens consists of antibody-mediated and T cell-mediated immunity. Structural and molecular biological studies have shown that the antibody response is tailored to provide exquisite specificity by generating binding pockets that are complementary in shape as well as in charge to the antigen. On the other hand, the cellular response uses T-cell receptors (TCRs) and the major histocompatibility complex (MHC) antigens. Structural information on the TCRs is not yet available, but the crystal structures of several MHC class I molecules have shown how one MHC molecule can bind many different peptide sequences that share only the common anchor residue positions that determine allele specificity. MHC class I interactions with the peptide backbone at the N and C termini explain the high specificity of the binding groove for peptide ligands and suggest a universal mode of recognition for peptides to MHC class I molecules. Peptide-MHC class II interactions are less well understood, although recent structural work has shown important differences in the binding clefts of MHC class I and II that lead to longer peptides being bound to class II molecules. Detailed analysis at the molecular level has indicated that conformational changes in both antibodies and MHC molecules occur upon antigen binding.(ABSTRACT TRUNCATED AT 250 WORDS)     

Aminopeptidases in cells of non-Hodgkin's lymphoma of varying degrees of malignancy and in lymphogranulomatosis

26 cases of lymphoproliferative diseases were studied: 8 cases of reactive follicular hyperplasia (RFH), 11 cases of non-Hodgkin's malignant lymphomas (NML), 7 cases of lymphogranulomatosis (LGM). Only gamma-glutamyl transpeptidase (GGT) was found in lymphoid cells of B- and T-dependent areas of lymph nodes with reactive changes as well as in tumor cells of NML and LGM. GGT activity was more pronounced in NML of high-grade malignancy (centroblast and immunoblast) as compared to lymphomas of lower grade of malignancy (lymphocytic, centroblast-centrocytic and in Lennert lymphoma). GGT activity in cells of Hodgkin and Berezovsky-Sterberg in some cases of LGM was high, in others low. Significant differences in GGT activity between RFH and follicular centroblast-centrocytic lymphoma were not found. Activity of aminopeptidase M was observed in histiocytes, fibroblasts, vessels and areas of connective tissue growth. Aminopeptidase A activity was observed in vessels only. Activity of dipeptidyl(amino)peptidase IV was observed in some lymphoid cells in RFH, NML and LGM. Thus, GGT activity may be considered as a differential-diagnostic marker in separating NML of high and low degree of malignancy and this may presume a different sensitivity to the therapy.     

Long-term outcome of a prospective randomized trial of conversion from cyclosporine to azathioprine treatment one year after renal transplantation

BACKGROUND: Since the introduction of cyclosporine (CsA), 1-year renal allograft survival has improved, but concern persists about the long-term adverse effects of CsA, especially with respect to renal function and blood pressure. This randomized controlled trial was set up to establish whether withdrawal of CsA would alter long-term outcome. METHODS: Adult patients who, at 1 year after renal transplantation, had a stable serum creatinine of less than 300 micromol/L and who had not had acute rejection within the last 6 months were eligible for entry. Patients were randomized either to continue on CsA (n=114) or to stop CsA and start azathioprine (Aza, n=102). All patients remained on prednisolone. Median follow-up was 93 months after transplantation (range: 52-133 months). RESULTS: There was no significant difference in actuarial 10-year patient or graft survival (Kaplan-Meier), despite an increased incidence of acute rejection within the first few months after conversion. Median serum creatinine was lower in the Aza group (Aza: 119 micromol/L; CsA. 153 micromol/L at 5 years after randomization, P=0.0002). The requirement for antihypertensive treatment was also reduced after conversion to Aza; 75% of patients required antihypertensive treatment at the start of the study, decreasing to 55% from 1 year after randomization in the Aza group and increasing to >80% in the CsA group (55% (Aza) and 84% (CsA) at 5 years after randomization, P<0.005). CONCLUSIONS: Conversion from CsA to Aza at 1 year after renal transplantation results in improvement in both blood pressure control and renal allograft function, and is not associated with significant adverse effects on long-term patient or graft survival.     

聚酯酰胺热熔胶的合成及其性能研究

研究了以聚酯胶和聚酰胺胶为原料在催化剂作用下加热共熔,通过大分子链交换反应制备织物用聚酯酰胺热熔胶的方法。用聚酯胶的溶剂对所得产品进行溶取试验并且通过红外光谱分析都证明了链交换反应的存在。用该法所得产品粘接强度大,既耐水洗又耐干洗,适用于粘合衬生产。     

基于灰色关联分析的卫星初始轨道优选方法

卫星初始轨道优选是一项复杂而且具有多目标性的问题,所以必须利用一系列的评价指标才能全面系统地评价各种初始轨道.针对各种数据源确定的多组初始轨道如何选优问题,提出了一种应用于卫星初始轨道优选的灰色关联分析方法,建立了初始轨道选优的评价指标体系,成功地利用标称轨道作为属性基向量,解决了比较数列的生成问题并给出了具体的应用实例.实例计算结果表明,该方法计算简单,结果可靠,可为决策者的选择提供依据.     

Evolution of gypsy-group retrotransposons: phylogenetic analysis of domains included in the pol-polyprotein

Transposons of gypsy group are assigned to LTR-containing retrotransposons present in the genomes of invertebrates, fungi, and plants. In this work, a theoretical analysis of the potential products of ORFs of these retrotranposons was conducted. Alignments were obtained and trees of similarity were constructed for domains of the POL region. On the basis of the obtained data, two hypothetically monophyletic subgroups of transposons were distinguished within the framework of the gypsy group, settling the genomes of taxonomically related organisms (the subgroup of "true" gypsy of insects and the subgroup of gypsy-like transposons of plants and fungi). A number of peculiarities of the topology of these trees hypothetically indicate cases of genetic conversion and recombination of domains accompanying the evolution of this group. The amino acid substitution fixation rate was evaluated on the basis of comparison of sequences of the protein products of ORFs. Estimates of the time of divergence of subgroups of gypsy-group transposons are significantly less than estimates of the times of divergence of their host species. One explanation for this discrepancy might be the hypothesis of settlement by transposons of the genomes of isolated host species.     

Body thiamine level in acute alcohol psychoses

PURPOSE: To compare admission data and academic performances of medical students younger and older than 25, and to qualify older students' experiences and perceptions in medical school. METHOD: The authors reviewed 1988-1991 data for applications to the McGill University Faculty of Medicine. Data included GPAs and MCAT scores, as well as ratings for reference letters, autobiographical statements, and interviews. For those same years, the authors measured students' academic performances in the preclinical and clinical years. The authors compared the data by students' age: "younger" students, aged 17 to 24; and "older" students, aged 25 and above. All enrolled students took the Derogatis Stress Profile, and the older students participated in focus groups. RESULTS: The older applicants had lower GPAs and MCAT scores, but higher interview and reference letter ratings. For older accepted students, basic science course scores were lower than those of younger students, but clinical scores did not differ significantly between the groups. The two groups had similar stress levels, although older students tested lower in driven behavior, relaxation potential, attitude posture, and hostility. In focus groups, the older students spoke of learning style differences, loss of social support, and loss of professional identity. CONCLUSION: Different scores in admission criteria suggest that McGill uses different standards to select older medical students. Older students admitted under different criteria, however, do just as well as do younger students by their clinical years. A broad-based study of admission criteria and outcomes for the older student population is warranted.