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Biomedical subjects

H Kirchner

Publications and source records attributed to H Kirchner.

At least 73 records · Page 4Linked to original sources
PubMed1999

Prognostic impact of in vivo soluble cell adhesion molecules in metastatic renal cell carcinoma.

The purpose of the study was to determine prognostic significance of pretreatment serum levels of different molecules involved in cell to cell interactions along with other clinical parameters in patients with metastatic renal cell carcinoma. sICAM-1, sVCAM-1 and sELAM-1 serum levels were determined by ELISA assays in sera from 99 patients with histologically confirmed progressive metastatic renal cell carcinoma prior to initiation of systemic therapy. Kaplan-Meier survival analysis, log-rank statistics and two-proportional Cox regression analyses were employed to identify risk factors and to demonstrate statistical independence. In univariate analyses, the following pretreatment risk factors could be identified: serum sICAM-1 level > 360 ng ml(-1), erythrocyte sedimentation rate > 70 mm h(-1), serum C-reactive protein level > 8 mg l(-1), serum lactic dehydrogenase level > 240 U/l and neutrophil count > 6000 microl(-1). Multivariate analyses demonstrated statistical independence for serum sICAM-1 level, erythrocyte sedimentation rate (ESR) and serum C-reactive protein (CRP) level as pretreatment predictors of overall patient survival. The prognostic significance of sICAM-1 might indicate a role of this molecule for tumour progression, potentially in association with the abrogation of anti-tumour immune responses. The possibility of defining a pretreatment risk model based on sICAM-1 level, ESR and CRP also warrants further investigation, with regard to a possible linkage between acute phase proteins and sICAM-1 levels.

Carcinoma, Renal Cell↗
PubMed1999

Analysis of Epstein-Barr virus (EBV) receptor CD21 on peripheral B lymphocytes of long-term EBV- adults.

Primary infections with EBV are rarely observed after the age of 20. Some individuals even remain seronegative all their lives. Previously, a lack of EBV receptors on B cells of persistently EBV- adults was described as a reason for long-term EBV-seronegativity. The present study examined the CD21 receptor status of 20 repeatedly EBV- healthy adults and 32 EBV+ volunteers by means of flow cytometry. CD21 molecules on the surface of CD19+ B cells were quantified using anti-IgG-coated microbeads. The percentage of CD19+/CD21+ B lymphocytes was slightly lower in the peripheral blood of EBV- donors, but the CD21 antibody binding capacity on CD19+ B cells showed no significant differences between EBV- and EBV+ adults. In vitro studies showed an equally good EBV transformability of peripheral B lymphocytes of EBV- and EBV+ donors. Since HLA-DR was recently described as a co-receptor for EBV infection of B cells, we also determined HLA-DRB1 alleles in the EBV- group. We found a significant negative association of EBV-seronegativity with HLA-DR13 in comparison with 111 healthy blood donors. In summary, a biologically significant lack of the EBV receptor CD21 on peripheral B lymphocytes of persistently EBV- adults was excluded as a reason for long-term EBV-seronegativity.

Adult↗
PubMed1999

A human whole-blood assay for analysis of T-cell function by quantification of cytokine mRNA.

A whole blood assay was developed for T-lymphocyte analysis which allows the quantification of induced cytokine mRNA expression. We applied a novel kinetic reverse transcription polymerase chain reaction method which directly measures product accumulation using Taqman technology. Quantitative results were obtained by using beta-actin and cytokine standard curves generated from synthetic external standards. Since quantification relies on threshold cycles for fluorescence detection (Ct), this technique proved to be accurate over a dynamic range of at least five orders of magnitude. To evaluate the method a study was undertaken to find optimal conditions for whole-blood stimulation with soluble anti-CD3 monoclonal antibodies in the presence of a costimulatory signal mediated by anti-CD28 monoclonal antibody. Therefore, whole blood was taken from healthy individuals (n = 10) and aliquots for mRNA measurement were withdrawn after 0, 4, 8 and 24 h of stimulation. Optimal assay conditions were reached with 1 : 10 diluted heparinized whole blood and after stimulation with equimolar amounts of anti-CD3 and anti-CD28 monoclonal antibodies (1 microgram/ml). Interferon-gamma and tumour necrosis factor-alpha proved to be early response cytokines with peak expression at 4 h. In contrast, interleukin (IL)-2, IL-4 and IL-10 required 8 h of stimulation. This novel whole-blood assay is potentially useful for monitoring T-cell-specific immune functions in a variety of clinical settings. Using whole blood obviates the need for T-cell purification and may therefore closely approximate the state of responsiveness of circulating T cells in vivo.

Biological Assay↗
PubMed1999

Preparation of autologous platelets for the ophthalmologic treatment of macular holes.

BACKGROUND: Platelet concentrates were recently used for ophthalmologic treatment of macular holes. This strategy was investigated to define standardized blood bank components. STUDY DESIGN AND METHODS: Two different, highly concentrated autologous platelet components, one from whole-blood preparation and the other from plateletpheresis, were evaluated. In the first procedure, platelet-rich plasma was obtained from 250 mL of whole blood. After storage for 20 hours, platelet-rich plasma was concentrated in a second centrifugation step and adjusted to 10 x 10(9) platelets per mL. In the second procedure, platelets were collected by apheresis, stored overnight, centrifuged, and adjusted to 20 x 10(9) platelets per mL. The respective component was instilled during vitrectomy and gas tamponade in patients with stage II to IV macular holes. Patients were followed for 9 months. RESULTS: With regard to the various preparation procedures and final concentrations of platelets in the components, no differences in wound healing were observed. An anatomic closure of the macular hole was achieved in 18 of 19 treated patients. Visual acuity improved in 14 patients. CONCLUSION: Both types of highly concentrated platelet components were effective in achieving high closure rates of macular holes. These autologous platelet components possess the quality standard of blood bank components and could be of great benefit for initiating wound healing in other clinical settings.

Adult↗
PubMed1999

Clinical and molecular findings in multiple sclerosis patients with type 1 diabetes mellitus.

The clinical and molecular findings in three patients with multiple sclerosis (MS) and additional type 1 diabetes mellitus are described. These patients all presented with a severe and progressive disease course of MS. Molecular testing for HLA class II genes demonstrated the presence of the haplotype DRB1*0401, DQB1*0302 in all patients. This haplotype is closely linked to type 1 diabetes mellitus and is increased among patients with the primary progressive subtype of MS. We conclude that the immunogenetic background in patients with diabetes mellitus may determine the severity and clinical course of MS in these individuals. Copyright 1999 Harcourt Publishers Ltd.

Journal Article↗
PubMed1999

Failure to detect antiviral activity in serum and plasma of healthy individuals displaying high activity in ELISA for IFN-alpha and IFN-beta.

The presence of constitutively produced interferon (IFN)-alpha in the blood of healthy individuals has been the subject of contradictory discussions for years. Immunologic as well as biologic test procedures have demonstrated striking differences regarding serum IFN-alpha under physiologic conditions. We investigated the presence of immunoreactive IFN-alpha in serum samples of 923 healthy blood donors by means of a widely used commercially available ELISA. Of these, 254 (27.5%) exhibited detectable serum IFN-alpha levels. The sera of 85.1% of these people also contained IFN-beta. Both IFN were also demonstrated in EDTA-anticoagulated plasma. However, none of these samples exhibited any antiviral effect on human A549 lung carcinoma cells challenged with encephalomyocarditis virus. Samples with high IFN-alpha ELISA activity did not abolish the antiviral action of added natural IFN-alpha, thus excluding IFN-alpha inhibitory factors. The experiments suggest that the detected compounds probably did not represent IFN-alpha but were the result of a cross-reaction with unknown serum components. A variety of disorders has been associated with elevated serum IFN-alpha levels that in most cases were detected by ELISA. In view of our data, these findings need to be carefully reevaluated. For the purpose of monitoring IFN-alpha levels in therapy of atopic, autoimmune, or malignant disorders, an appropriate detection system for IFN-alpha is advisable.

Antiviral Agents↗
PubMed1999

Mucosal cytokine expression, cellular markers and adhesion molecules in inflammatory bowel disease.

OBJECTIVE: To relate proinflammatory cytokines to leukocyte surface markers and adhesion molecules in the same paraffin-embedded biopsy specimen in inflammatory bowel disease (IBD) of varying activity. METHODS: Biopsies of seven cases of Crohn's disease, seven patients with ulcerative colitis, one case of intestinal infection and six control subjects were studied. We performed in situ hybridization on sections of tissue using probes specific to interleukin-1beta (IL-1beta), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF alpha). Leucocyte markers and adhesion molecules were investigated in subsequent slides of selected specimens by immunohistochemistry. RESULTS: Cytokine mRNA was found in large numbers of cells throughout the inflamed intestine but also in some macroscopically unaffected tissue specimens. Transcripts were predominantly located within the lamina propria where immunohistochemistry of parallel sections revealed numerous macrophages and the presence of endothelial adhesion molecules. The expression of the different cytokines was closely related to each other and to histological but not to macroscopic (endoscopic) activity. CONCLUSIONS: The synthesis of IL-1beta IL-6 and TNF alpha mRNA is coordinately regulated. Cytokine production is located mostly in the lamina propria at sites that are rich in macrophages and show abundant staining of vascular adhesion molecules. This cascade of immune events is related to inflammatory cell infiltration in both Crohn's disease and ulcerative colitis.

Adult↗
PubMed1999

Autoimmunity resulting from cytokine treatment predicts long-term survival in patients with metastatic renal cell cancer.

PURPOSE: In patients undergoing cytokine therapy, systemically applied interleukin-2 (IL-2) and/or interferon-alpha (IFN-alpha) have been reported to induce thyroid dysfunction as well as thyroid autoantibodies. We analyzed the correlation of thyroid autoimmunity with HLA phenotype, various other autoimmune parameters, and patient survival. PATIENTS AND METHODS: For this purpose, antithyroglobulin autoantibodies, antimicrosomal thyroid autoantibodies, thyroglobulin receptor autoantibodies, thyroid dysfunction, and multiple clinical parameters were determined in 329 unselected patients with metastatic renal cell cancer before and after systemic IL-2 and IFN-alpha2 therapy. For statistical analysis, we used both univariate and multivariate Cox proportional hazards models and the two-tailed Fisher's exact test. RESULTS: Antithyroglobulin autoantibodies and antimicrosomal thyroid autoantibodies were detected in 60 patients (18%); positive autoantibody titers of various other autoimmune parameters were statistically unrelated. The presence of thyroid autoantibodies was correlated with prolonged survival (P<.0001). There was a statistically significant difference in frequencies of HLA-Cw7 expression between thyroid autoantibody-positive and -negative patients (P< or =.05), and the Cw7 expression was associated with prolonged overall survival (P = .009). CONCLUSION: The evaluation of thyroid autoantibodies during cytokine therapy could be a useful prognostic marker for patients with renal cell carcinoma who benefit from cytokine treatment. IL-2- and IFN-alpha2-induced tumor control and prolonged survival may require breaking of immunologic tolerance against self-antigens.

Adult↗
PubMed1998

Evaluation of a flow cytometric method for simultaneous leukocyte phenotyping and quantification by fluorescent microspheres.

We describe a flow cytometric method using a newly designed product, fluorochrome-containing microspheres (Flow Count fluorospheres), which facilitates the precise quantification of cells in whole blood samples or heterogeneous cell suspensions on a single-cell level. These microparticles are easily distinguishable from other events of interest and can be detected by their light-scattering and fluorescence properties. In contrast to the traditional manual or automated cell-counting techniques, this method offers the opportunity to quantify cells simultaneously with flow cytometric immunophenotyping without additional cell loss or other cell preparation steps. We evaluated the accuracy and reproducibility of this flow cytometric method on the determination of CD45+ leukocyte counts and compared the results with those obtained by conventional techniques. Particular interest was focused on the behavior of cells and fluorospheres regarding their sedimentation rate over the period of analysis. The data from 48 blood samples with low, normal, and high leukocyte counts confirmed the reliability and comparability of the flow cytometric method, permitting the determination of white blood cell concentration at least to a limit of 100 cells/microL. A broad field of applications will benefit from this flow cytometric supplement because it is easy to perform and highly accurate. The results appear to be transferable to clinical decision-making monitoring of CD4+ lymphocytes in patients infected with human immunodeficiency virus or of CD34+ hematopoietic cells, optimizing the harvest for peripheral blood stem cell transplantation.

Antigens, CD34↗
PubMed1998

DNA typing for natural killer cell inhibiting HLA-Cw groups NK1 and NK2 by PCR-SSP.

Over the last few years, natural killer (NK) cells have been shown to express MHC molecule recognizing receptors which are thought to function primarily as negative signaling receptors. HLA-Cw seems to play a key role as the corresponding ligand. Two distinct HLA-Cw groups which differ in amino acid residues 77 and 80 inhibit separate subsets of NK cells. In order to classify target cells with respect to their expression of HLA-Cw groups we established a group specific PCR-SSP which directly amplifies the relevant epitope coding sequences. The PCR protocol was validated by retyping cell lines obtained from the International Histocompatibility Workshop and by comparing those results with those acquired from allele-specific genotyping and serotyping on 80 donor-recipient pairs from our kidney transplantation unit. In the context of inhibitory HLA-Cw receptors, our protocol which definitively discriminates the two alternative epitopes is the more direct and thus more reliable approach, and is less labor intensive compared to an allele specific PCR or serotyping. In addition serotyping does not detect at all certain alleles. Basic NK cell research and clinical transplantation immunology may benefit from this newly established PCR SSP technique.

Cell Line↗
PubMed1998

Lack of evidence for Marek's disease virus genomic sequences in leukocyte DNA from multiple sclerosis patients in Germany.

Herpes viruses have repeatedly been associated with the etiology of multiple sclerosis (MS). In the course of investigations on a cluster of MS patients in Key West, Florida, it was suggested that Marek's disease virus (MDV), a cell-associated avian herpes virus, might be involved in the pathogenesis of the disease. The aim of our study was to investigate 107 well-defined MS patients with regard to latent MDV infection. Using a highly-sensitive polymerase chain reaction technique, we did not find MDV-related sequences in leukocyte DNA of any of the patients. The results of our study do not suggest an implication of MDV in the pathogenesis of MS.

DNA, Viral↗
PubMed1998

Increased serum neopterin levels in acutely ill and recovered schizophrenic patients.

Twenty-nine in-patients with acute schizophrenia were examined to assess serum neopterin levels by ELISA at two points of time: during the state of acute symptoms and after clinical recovery at the point of discharge (at an interval of 30.84 +/- 15.22 days). Patients showed significantly higher levels of neopterin than controls. Moreover, the neopterin levels were significantly higher in patients after clinical improvement than in acutely ill patients. Neopterin levels in patients after clinical recovery were negatively correlated to scores of psychopathological symptoms, and positively to neuroleptic medication at the acute stage of the disease. The increase of serum neopterin during treatment of schizophrenia may reflect an up-regulation of dopamine turnover, rather than immunological activity.

Acute Disease↗
PubMed1998

Altered cytokine production in the elderly.

Elderly persons are more susceptible to bacterial and virus infections and neoplasias than young adults. This is related to an impaired immune response. Lymphocytes of the elderly show a decreased proliferation after induction with mitogens. The decreased proliferation is correlated to a decreased release of interleukin (IL)-2 and soluble IL-2 receptor (sIL-2R). However, IL-2R expression on the cell surface is normal. Interferon (IFN)-gamma as the main T-helper-1 (TH1) cytokine is produced less by lymphocytes of the elderly, whereas the TH2 cytokines IL-4 and IL-10 are produced in higher amounts as compared to stimulated lymphocytes of young donors. The decreased production of IFN-gamma is correlated to a decreased number of CD45RO+/CD8+ T cells. Therefore in the elderly there seems to be a dysregulation in the TH1/TH2-system which is predominated by TH2-functions. Monocyte function seems to be increased in the elderly. Leukocytes of elderly persons produce higher amounts of IL-1, IL-6, IL-8 and tumor necrosis factor (TNF)-alpha after induction with lipopolysaccharide (LPS) than leukocytes from young donors. In contrast, in vitro induction of IFN-alpha by viruses is decreased in the elderly compared to the young. In conclusion, there are cellular defects and dysfunctions in the elderly resulting in an altered immune response.

Adult↗
PubMed1998

[Cytokine release and changes in mononuclear cells in peripheral blood under the influence of general anesthesia].

OBJECTIVE: Anaesthetic agents are believed to have an adverse effect on human immune defense mechanisms. We investigated changes in peripheral immune cell numbers such as natural killer (NK) cells, B cells and T lymphocyte subpopulations (CD4+ and CD8+ cells) and differences in cytokine production after stimulation with different mitogens before and during narcosis. METHODS: We studied 30 patients undergoing elective orthopedic surgery. Stimulatory experiments were performed with the mitogens lipopolysaccharide (LPS), phytohemagglutinin (PHA) and inactivated Newcastle Disease Virus (NDV). RESULTS: During general anaesthesia with fentanyl, thiopental, isoflurane and nitrous oxide there was a significant decrease of circulating NK cells in the peripheral blood accompanied by a significant increase of B cells and CD8+ T lymphocytes. We detected a significant anesthesia-associated increase of interferon (IFN)-gamma, INF-alpha, tumor necrosis factor (TNF)-alpha and soluble interleukin-2 receptor (sIL-2R) synthesis after stimulation with different mitogens while interleukin (IL)-1 beta and IL-6 protein did not change significantly. After the beginning of surgery CD8-positive cells showed a return to control values and NK cell number increased slightly. CONCLUSION: These findings suggest that general anaesthesia interferes with immune cell number and immune cell response. This may explain the clinically well-recognized disturbance of human immunity after surgery and general anaesthesia.

Adolescent↗
PubMed1998

Pseudo-exclusion from paternity due to maternal uniparental disomy 16.

The investigation of a case of disputed paternity revealed indirect exclusion of the alleged father in the haptoglobin system and in the DNA single-locus system D16S309/Hinf I (MS205). The paternity index for the non-exclusion systems was > 10(6). Since both exclusion systems (HP and MS205) are located on chromosome 16, we investigated 10 microsatellite loci covering this chromosome with 10-20 cM resolution. Analysis of the child's chromosome showed only alleles of maternal origin and lack of inheritance of paternal alleles for five informative loci. The markers close to the centromere of chromosome 16 were heterozygous, whereas distal loci were either heterozygous or homozygous for maternal alleles. This is consistent with a maternal meiosis I nondisjunction of chromosome 16 leading to maternal uniparental heterodisomy. This case emphasizes that the opinion of non-paternity should be based on the absence of paternal alleles at genetic systems located on at least two different chromosomes.

Alleles↗
PubMed1998

A method to determine the 3-D stiffness of fracture fixation devices and its application to predict inter-fragmentary movement.

Inter-fragmentary movement considerably influences the fracture healing process. Large shear movement delays while moderate axial movement stimulates the healing process. To be able to control the mechanical situation at a fracture site and to achieve optimal bony healing it is essential to understand the relationship between inter-fragmentary movement, bony loading and fixation stiffness. A 6 x 6 stiffness matrix is introduced which completely describes the linear relationship between the 6 inter-fragmentary movements and the resulting bony loading (3 forces and 3 moments). Further, it is illustrated that even in relatively stiff external fixateur constructs simple axial loading of the bony fragments leads to complex inter-fragmentary movement. When the 3-D stiffness description is multiplied by the load state in sheep tibiae, movements similar to those measured in vivo are calculated. The relationship between axial compression and medio-lateral or dorso-ventral shear varies depending on the mounting plane of the external fixateur. The authors conclude that a single value is not sufficient to describe the mechanical relationship between inter-fragmentary movement and bony loading. Only a complete description of fixation stiffness allows prediction of inter-fragmentary movement and differentiation between various configurations of fixation devices and their potential for mechanically promoting bony healing.

Animals↗