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Biomedical subjects

G László

Publications and source records attributed to G László.

At least 19 recordsLinked to original sources

Differential expression of GL7 activation antigen on bone marrow B cell subpopulations and peripheral B cells.

GL7 was originally described as a 35-kDa late activation antigen on mouse T and B cells. GL7 expression has also been demonstrated on thymocytes, germinal center B cells and some neuronal cell types. Flow-cytometry and immunohistochemistry were used to follow changes in the expression of GL7 during B cell development, amongst B cell subpopulations and various anatomical locations. GL7 is expressed as early as the pro-B cell stage and increases up to the pre-B-I stadium. Expression remains high on pre-B-II and on immature B cells, although slightly decreases during maturation. GL7 is almost completely downregulated when IgD appears on the cell surface. On the periphery only a few B cells are positive and these cells are almost exclusively found in the sIgD- germinal center areas of lymph nodes and spleen. The staining pattern of GL7 is very similar to that of PNA in the lymph nodes but in the bone marrow we have found both B220+PNA+GL7- and B220+PNA+GL7+ populations, showing that GL7 and the antigen recognized by PNA are different. After in vitro stimulation, the GL7(hi) B cell population has also been found to be IgD negative. Functional comparison between in vitro activated and MACS sorted GL7(hi) and GL7(lo/-) spleen B cells of immunized mice showed significantly higher specific and total antibody production as well as antigen presenting capacity in the GL7(hi) population.

Animals↗

[2-year results of leg amputation in Hungary based on a nationwide data base].

Authors review nation-wide hospital data of amputees over two years in order to make comparison with similar data gathered about 20 years ago. Data were provided by the National Medical Records Centre and processed by own developed programmes. The quality level of data validity is slightly criticised. The cause of amputation was most often vascular disease, amputees were elderly and large majority of amputation surgery was carried out on the lower limb. The rate of below-knee amputation has gone up favourably over the 20 years, but there are large regional differences within the country. Mortality parameters remarkably exceed those of foreign countries. Regarding compromised data accuracy, still there are ways of exploiting data in favour of quality improvement of care, e.g. improve below-knee amputation rate, reduce mortality. Publication of data can be of bench-marking importance for hospitals by enabling them to compare own results with those of other hospitals, as well as develop and improve performance.

Amputation, Surgical↗

Collaboration of TCR-, CD4- and CD28-mediated signalling in antigen-specific MHC class II-restricted T-cells.

A previously developed experimental system was applied to obtain qualitative and quantitative data on the contribution of TCR-, CD4- and CD28-mediated signalling in the activation of an antigen specific T-cell hybridoma. All the three signal transducing receptors were stimulated by their natural ligands, and intermediate and late responses of an I-Ed restricted, CD4 +, influenza HA specific murine T-hybridoma (IP-12-7) were monitored by measuring the concentration of intracellular calcium [Ca2+]i and secreted IL-2. This type of analysis of T-cell activation revealed: (i) calcium mobilization induced by peptide loaded APC requires rapid conjugate formation; (ii) a direct correlation between the magnitude of the intermediate and the late responses was observed as a consequence of differential TCR ligation modulated by peptide dose or by the presence CD4; (iii) considering the APC/peptide and T/APC ratios, the concentration dependence of the intermediate and late responses was similar in both assays but a substantial difference in the sensitivity of the two methods was observed; (iv) CD4 mediated signalling has a co-stimulatory effect predominantly at suboptimal in vitro conditions; and (v) sustained increase of [Ca2+]i as well as the production of high concentrations of IL-2 is highly dependent on the CD28-B7 interaction. These results demonstrate that distinct peptide doses and the presence or absence of CD4 result in quantitative changes in T-cell responses, while the degree of CD28 mediated signalling has a qualitative affect on the outcome of T-cell activation, revealed by complete or partial inhibition of IL-2 secretion as a result of limited CD28-B7 interaction as well as by alteration in the duration and time kinetics of the calcium response.

Animals↗

[Observations on real drug need of hospitals].

Authors indicate that a considerable share of the inpatient drug supply "gets out" of the institution, another remarkable share is administrated to patients due to polypragmasia. Consequently, in-patient drug-costs might be reduced by large amounts without jeopardizing the quality of care. Authors made attempts to measure the first of the two mentioned losses by repeated systematic observation of patients' clinical charts, while the second one was assessed by several peer-reviews. Illegal drug losses were tackled by involving an external ordinary drugstore, to deliver hospital staff members prescription drugs, while polypragmasia was successfully reduced by introducing changes derived from reports of peer-reviews, over the past three years. Additionally, since the most costly group of drugs is that of the antibiotics, an internal treatment protocol system was set up based on collective knowledge and consensus of all doctors. Authors recommend that once all listed management activities are introduced and conducted in a hospital, department-specific daily drug-cost rationing can be created fairly based on the average drug consumption of the respective department.

Drug Costs↗

[Experience with the surgical management of primary and secondary chondrosarcoma].

Forty eight primary and 20 secondary chondrosarcomas were treated surgically 1975 through 1991. An evaluation of the data of the Bone Tumor Register of the Semmelweis Medical University proved that the incidence of the malignant transformation and development of secondary chondrosarcomas is 3% and 2.6% among solitary osteochondromas. The authors summarize the clinicopathological characteristics of the malignant transformation. A retrospective evaluation of the histological grade of the malignancy proved that 67% of tumors were classified as grade I; 18% as grade II and 15% as grade III. The survival of the patients was mainly determined by the grade of the malignancy. A 95% 5-years survival was found in the grade I group and a 10% survival only in the grade II and III groups. In the cases of highly malignant chondrosarcomas radical surgical intervention i.e. amputation is recommended, considering the most often extra-compartmental location of the tumors. Low malignant and intra-compartmental highly malignant chondrosarcomas should be treated, however, by limb saving surgery. In the cases of large inresecable but low malignant chondrosarcomas debulking surgery is also acceptable.

Adolescent↗

[Results of amputation and rehabilitation].

Authors report on a questionnaire study of amputees having been rehabilitated in three departments of the National Institute of Medical Rehabilitation in 1988. The study was conducted one and a half years (average) after amputation. In comparison to an earlier study on a similar population the ratio of distal amputations has increased and the prosthetic fitting has improved. From these points results are well comparable with international standards. The feeling of isolation of the amputees has decreased since the earlier study. Their chance to get a job has deteriorated essentially, their subsistence problems have increased.

Adolescent↗

Isolation and characterization of IgG2a-reactive autoantibodies from influenza virus-infected BALB/c mice.

Repeated influenza virus infection induces the production of dominantly IgG2a-type virus-specific antibodies as well as the appearance of IgG2a-reactive autoantibodies in BALB/c mice characterized by low spontaneous rheumatoid factor-type autoantibody production. IgG2a-reactive autoantibody-producing hybridomas could be isolated from the spleen of influenza virus-infected BALB/c mice. The mAb produced by these clones represent not only IgM but also IgG and IgA isotypes and show strong isotype or isoallotype specificity. The common functional property of these autoantibodies is their preferential- and high-affinity binding to complexed, solid-phase-bound or heat-aggregated IgG2a when compared to native soluble or cell-bound IgG2a. The mechanism of induction and the possible biological function of these autoantibodies are discussed in the light of their fine specificity and functional properties.

Animals↗

In vivo manipulation of IgG2a production by isotype-specific autoantibodies.

Repeated intranasal infection of Balb/c mice with A/PR/8 influenza virus induced an intense antiviral IgG response dominated by the IgG2a subclass, and accompanied by the appearance of IgG2a reactive autoantibodies. Cells producing IgG2a reactive autoantibodies could then be cloned as hybridomas from the virus infected animals. Monoclonal antibodies produced by selected hybridomas U28, Z26 and Z41 produced IgM-type antibodies with strong specificity for the IgG2a isotype bearing "a" allotypic determinants on the Fc region. These IgG2a specific autoantibodies showed highly preferred binding to solid phase bound or aggregated IgG2a, compared to soluble native IgG2a. Based on these characteristics they were classified as mono-reactive rheumatoid factor (RF)-like autoantibodies. Passive administration of IgM type IgG2a-specific autoantibodies to influenza virus infected animals resulted in a long-term reduction in the secondary antiviral response. This could be demonstrated by decreased virus neutralizing activity of the serum and diminished level of IgG2a-type anti-viral antibodies. A similar effect was observed in Balb/c mice contact sensitized with oxazolone: passive administration of RF-like antibodies resulted in reduced IgG2a response to oxazolone while the level of antibodies belonging to other isotypes was not influenced. These results suggest an isotype-specific regulatory function of these RF-like autoantibodies presumably acting via antigen-antibody complexes.

Animals↗

[Management of critical ischemia of the leg by omentum transplantation in Buerger's disease].

Author reviews cryptogenic etiology, and poor prognosis of endarteriitis obliterans (Buerger's disease), traditional salvage measures and their temporary effectivity. Based on theoretical, animal experimental and clinical studies chances of new operative measure: omental transplantation are suggested. Two own cases operated on and promising results of the short follow-up period (6 and 9 months) are reported.

Female↗

Structural characteristics influencing the carrier function of synthetic branched polypeptides based on poly[Lys-(DL-Ala)3)]backbone.

Effective carrier function of selected representatives of new branched polypeptides covalently coupled with the synthetic monovalent hapten, oxazolone was studied. The effectiveness of oxazolone-synthetic polypeptide conjugates in inducing oxazolone-as well as carrier-specific antibody responses in inbred mice was compared to that of bovine serum albumin (BSA)- and KLH-oxazolone conjugates. The synthetic polypeptides, poly[Lys-(D-Leui-DL-Alam)] (D-LAK), LAK and FAK, as well as the common poly[Lys-(DL-Alam)](AK) core covalently coupled to oxazolone (Ox) induced a T cell-dependent antibody response when repeatedly administered with or without Freund's adjuvant in mice. This was evidenced by: the increasing titer of oxazolone-specific IgG during the course of the memory response; the appearance of all IgG subclasses; the effective oxazolone-specific priming by the conjugates; and the induction of an intense oxazolone- and carrier-specific DTH reaction. Although the oxazolone-specific antibody response was 10-100 times lower than that induced by KLH- or BSA-oxazolone conjugates, it was accompanied by a lower level or no detectable carrier-specific antibody response despite an effective carrier-specific T cell-mediated response. Significant differences were observed between the effectiveness of synthetic polypeptides used as carrier: highest oxazolone-specific antibody titers were observed using the AK, LAK and FAK conjugates. The intensity and specificity of the DTH reaction and antibody response induced by the carrier-oxazolone conjugates suggested that the distinct effectiveness of L- and D-amino acid-containing conjugates (LAK vs D-LAK and FAK vs D-FAK) was dependent on altered B cell recognition of the haptenic group. Circular dichroism (CD) spectra indicating different local orientation of oxazolone, when coupled to L or D side chain-terminating amino acids, support this suggestion.

Amino Acids↗

Activity of epirubicin and dibromodulcitol in advanced breast cancer. Results of the South-East European Oncology Group Study.

The therapeutic efficacy of the combination of epirubicin + dibromodulcitol was evaluated in 108 previously treated or untreated patients with advanced breast cancer. The overall response rate was 39.8%, complete remission 3.7% (mean duration 6.3 months) and partial remission 36.1% (mean duration 3.5 months). The response was rated in function of age, menopausal status, performance status and previous therapy. Toxicity (in case of 115 patients) was evaluated according to the WHO recommendation. The similar therapeutic effectiveness and less toxicity of the above drug combination compared to ADM + DBD regimen are demonstrated.

Adult↗

Hip disarticulation in peripheral vascular disease.

The authors had to perform hip disarticulation on vascular patients in an increasing number - in spite of the general amputation principles. In the majority of the cases hip disarticulation followed other, more distal amputations of the same lower limb. Results of wound-healing, prosthetic fitting and mortality are poor, nevertheless this operation may lengthen life, relieve pain and lead to a tolerable life, usually bound to wheel-chair.

Adult↗

The immunomodulatory effect of human IgG Fc fragments on the oxazolone-specific immune response of high and low responder mice.

Intravenous injection of human IgG Fc fragments in mice resulted in the stimulation or inhibition of an oxazolone-specific antibody response depending on the schedule of Fc fragment injection. High and low responder mice for oxazolone were injected with Fc fragments according to two protocols: either on the day of oxazolone priming, or together with the oxazolone boost, and the isotype composition of oxazolone-specific antibodies was analysed by solid phase radioimmunoassay. We found the primary and secondary anti-oxazolone IgM levels increased in all instances, irrespective of the schedule of Fc fragment treatment. In contrast, the oxazolone-specific IgG production was increased only if Fc fragments were injected at the time of antigen priming. Injection of Fc fragments together with a secondary injection of oxazolone resulted in the inhibition of oxazolone-specific IgG production. Both stimulation and inhibition of oxazolone-specific antibodies were more pronounced in the low responder C57BL/6 mice strain.

Animals↗

The influence of Igh-1 genes on the class and subclass distribution of oxazolone-specific antibodies.

Previous studies have demonstrated that the level of the oxazolone-specific antibody response induced by contact sensitization is under the control of H-2 and Igh-1-linked genes. The aim of the present study was to clarify the role of H-2 and Igh-1 genes in the regulation of antibody affinity and isotype composition of oxazolone-specific antibodies. Analysis of the antibody response to oxazolone has revealed different ratios of IgG2a and IgG2b antibodies in mice carrying the Igh-1b allele and in strains carrying alleles a, c, and e. The characteristic ratio of IgG2a and IgG2b isotypes persisted during the whole period of the primary and secondary antibody response of CBA and CBA-Igb Igh-C congenic mice. The Igh-1-linked genes influenced the isotype distribution and not the affinity of oxazolone-specific antibodies induced by contact sensitization.

Animals↗