Biomedical subjects

M Heberer

Publications and source records attributed to M Heberer.

At least 73 records · Page 4Linked to original sources

PubMed1994

[Surgical technique in vascularized auto- and allotransplantation of the knee joint in a dog model].

Experimental transplantation of vascularized canine knee joints has so far been associated with high complication rates in both auto- and allografts. We have now compared 4 autografts and 4 allografts that were successfully performed at our institution. This report details our surgical technique. Stable internal fixation enabling immediate postoperative weight bearing, microsurgical end-to-end anastomoses of popliteal artery and vein and postoperative control of immunosuppression in transplanted animals are crucial. Thus, an interdisciplinary approach of experts in microsurgery, orthopedic and trauma surgery and immunologists appears to be a prerequisite for successful joint transplantation.

Animals↗

PubMed1994

[Stable joint-bridging extension of malleolar dislocations and pilon fractures with the AO pinless external fixator].

The pinless external fixator, introduced into clinical practice for open tibial fractures, suggested itself for use as a traction substitute because of its pinless frame. The aim of this feasibility study was to replace the conventional calcaneal pin traction by a joint-bridging pinless fixator, inserted under local anesthesia. 10 patients with 6 malleolar dislocation fractures, 3 pilon tibial and 1 open distal tibial fracture were immobilised by a joint-bridging pinless fixator during 10.4 days (5-16 days) till swelling had subsided and definitive fracture treatment, consisting of plate fixation, took place. The implantation of the joint-bridging pinless fixator in local anaesthesia was well tolerated by all patients. This traction substitute offered good patient comfort and easy care. Although the provided stability was less than a conventional fixator, all patients were able to lift up their fractured extremity without pain.

Aged↗

PubMed1993

[The DHS (dynamic hip screw) buttress plate in the management of unstable proximal femoral fractures].

The DHS-implant system is a technically simple and widely used operative treatment modality for pertrochanteric fractures of the femur. In unstable 4-part fractures rotation of the head and neck fragment around the lag screw and significant impaction might lead to lateralisation of the greater trochanter and therefore to marked shortening. To prevent these effects we treated 17 patients with 4-part fractures with a prototype of a modular trochanteric DHS buttress plate. With this additional implant lateralisation of the greater trochanter could be prevented in all cases. This also leads to a limitation of telescoping, with less shortening even with immediate full weight bearing.

Adult↗

PubMed1993

Cytokine gene transcription in renal cell carcinoma.

Cytokines are powerful modulators of immune responses, the local production of which could be relevant to the interaction between tumour and immune system. This study investigated the transcription of genes encoding interleukin (IL) 2, IL-4, IL-10 and interferon (IFN) gamma in lymphocyte-infiltrated renal cell carcinoma biopsies from ten patients using the reverse polymerase chain reaction technique. Autologous peripheral blood mononuclear cells and healthy renal parenchyma tissue were tested in parallel. The beta-actin gene, used as a positive control, was transcribed in all samples. In contrast, transcription of cytokine genes was confined to tumour biopsies: IL-2 gene transcripts were detectable in five biopsies and IL-10 transcripts in seven. IL-4 and IFN-gamma gene transcripts were detectable in one biopsy each. In two patients no cytokine gene transcription could be identified. These data underline that heterogeneous patterns of cytokine gene transcription can be observed in renal cell carcinoma biopsies. Although transcription of an immunostimulatory lymphokine such as IL-2 was observed in 50 per cent of biopsies, the most frequently transcribed cytokine gene coded for an inhibitory factor, IL-10.

Aged↗

PubMed1993

Exogenous glutamine requirement is confined to late events of T cell activation.

Glutamine is required for the proliferation of lymphocytes, but quantitative effects on discrete steps of activation remain unknown to date. Therefore the influence of glutamine (range: 0 mM-1 mM) on the in vitro response of human peripheral blood mononuclear cells (PBMC) to a mitogenic anti-CD3 monoclonal antibody (mAb) was investigated. Expression of surface activation markers by flow cytometry, presence of mRNA of cytokine genes by polymerase chain reaction, release of cytokines by ELISA, and entering into the cell cycle by flow cytometry were sequentially analyzed. Proliferation was measured by a 3H-thymidine incorporation assay. mRNA coding for IL-2, IL-2 receptor, IL-4, IL-5, GM-CSF, and IFN-gamma was detectable independently from exogenous glutamine provision; expression of the cell surface activation marker CD69 was also glutamine independent. In contrast, later activation events including the expression of the surface activation markers CD25, CD45RO, and CD71 as well as the production of IFN-gamma were found to require exogenous glutamine supply. In contrast, production of TNF-alpha could be observed in the absence of glutamine and was increased to a limited extent by exogenous glutamine. The overall lymphocyte response as reflected by entering into the cell cycle and proliferation was directly correlated with the glutamine concentration of the culture medium. Efficient progression through the cell cycle was found to require at least 0.5 mM glutamine and an increase in glutamine concentration from 0.1 mM to 1 mM enhanced proliferation by 50%. These results were supported by data obtained following anti-CD3 stimulation of a CD4+ T cell clone.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, CD↗

PubMed1993

On the relative roles of interleukin-2 and interleukin-10 in the generation of lymphokine-activated killer cell activity.

Induction of cytokine gene transcription by recombinant human IL-2 (rhIL-2) in peripheral blood mononuclear cells (PBMC) from healthy donors was studied by qualitative polymerase chain reaction. In all donors tested, optimal doses of rhIL-2-induced transcription of genes encoding for IL-5, GM-CSF, IFN-gamma, and TNF-alpha whereas transcription of IL-1-alpha, IL-3, IL-4, and IL-6 genes could only be detected in about half of the donors. Moreover, we observed that different doses of rhIL-2 were needed to induce transcription of different cytokine genes. In contrast, transcription of IL-2 and IL-10 genes was only observed in a minority of donors, irrespective of the concentration of rhIL-2 used. Since IL-10 displays a well-characterized inhibitory activity on the synthesis of cytokines possibly involved in the generation of lymphokine-activated killer (LAK) cells, we asked whether the absence of IL-10 gene transcription plays a role in the induction of LAK cells. Thus, we tested the effects of different doses of rhIL-10 on the rhIL-2-driven generation of LAK activity. Interestingly, rhIL-10 dose-dependently inhibited the production of IFN-gamma and TNF-alpha induced by IL-2, but had no effects on PBMC proliferation and generation of LAK activity. Similarly, purified CD3-/CD16+ lymphocytes, the precursors of LAK effector cells, could be optimally induced by low doses of rhIL-2 to proliferate and generate MHC-unrestricted cytotoxic activity against NK-resistant targets in the presence of rhIL-10. Altogether, our results indicate that rhIL-2 induces transcription of a preferential pattern of cytokine genes, with the IL-10 gene being infrequently transcribed. On the other hand, rhIL-10 shows diverse effects on rhIL-2-triggered PBMC activation, in that it inhibits IFN-gamma and TNF-alpha production but does not affect PBMC proliferation or generation of LAK activity.

Base Sequence↗

PubMed1993

Differential effects of interleukin-2 and CD3 triggering on cytokine gene transcription and secretion in cultured tumor infiltrating lymphocytes.

The therapeutic potential of tumor-infiltrating lymphocytes (TIL) is currently under investigation. TIL have been reported to display characteristic functional defects, including impairments of activation mechanisms. In animal models, therapeutic efficacy of adoptive TIL transfer has been correlated with their capacity to produce cytokines rather than with their in vitro cytotoxic potential. In this work we assayed cytokine gene transcription and protein production in eight cultured TIL populations stimulated with recombinant human IL-2 (rhIL-2), solid-phase-bound anti-CD3 monoclonal antibodies (mAb), or a combination of the two. By using a sensitive reverse polymerase chain reaction technique, we observed that transcription of IL-5, GM-CSF, and TNF-alpha could be detected in unstimulated, IL-2-starved TIL from all cultures, while IL-4 and IFN-gamma genes were found to be transcribed in two cultures out of eight. A 50 U/ml dose of rhIL-2 was sufficient to induce IL-4 and IFN-gamma gene transcription in the remaining six cultures and in four more TIL populations, respectively. In contrast, rhIL-2 could not induce IL-2 gene transcription in five of eight TIL cultures. Furthermore, it could not induce IL-10 gene transcription in any TIL population. Anti-CD3 mAb triggering, however, induced transcription of all these cytokine genes. On the other hand, IL-6, IL-7, or TGF-beta 2 gene transcription could not be induced by any of the stimuli used, including the combination of anti-CD3 and rhIL-2. Despite detection of their gene transcripts, GM-CSF, IFN-gamma, or TNF-alpha was never detectable, at the protein level, in unstimulated TIL. Stimulation by rhIL-2 induced GM-CSF secretion, albeit to different extents, in all TIL populations. In contrast, rhIL-2 induced IFN-gamma and TNF-alpha production in three and one TIL population, respectively. CD3 triggering however, induced cytokine production in all TIL populations. Addition of rhIL-2 significantly increased production of GM-CSF, but not of IFN-gamma and TNF-alpha. These data underline that stimulation with a moderate dose of rhIL-2 reveals considerable heterogeneity of TIL populations regarding cytokine gene transcription and secretion. On the other hand, triggering of the CD3-T-cell receptor complex induces transcription of an extended panel of cytokine genes in all TIL populations and secretion of GM-CSF, IFN-gamma and TNF-alpha in virtually all cultures. Thus, if stimulated by properly presented antigenic peptides, TIL are capable of mounting an efficient response in terms of cytokine gene expression and protein production.

Aged↗

PubMed1993

Cytokine gene expression in primary brain tumours, metastases and meningiomas suggests specific transcription patterns.

To obtain an insight into the network of cytokine gene transcription in the brain tumour microenvironment, we investigated the expression of genes encoding for interleukin (IL)-1 alpha, IL-1 beta, IL-2, IL-4, IL-5, IL-6, IL-10, interferon (IFN)-gamma, granulocyte-macrophage colony-stimulating factor, tumour necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta 1, -beta 2 and -beta 3 in freshly excised brain tumour samples and autologous peripheral blood mononuclear cells. Tissue specimens from 15 primary brain tumours, three brain metastases, five meningiomas, autologous peripheral blood mononuclear cells (PBMC) and three brain tumour cell lines were tested by reverse polymerase chain reaction. Despite the presence of T-lymphocytes, cytokine gene transcripts typically detectable upon T cell receptor triggering could not be observed in central nervous system tumours of diverse histology. In primary brain neoplasms, transcription of genes encoding for the inhibitory cytokines TGF-beta and IL-10 was detectable in more than 50% of samples. IL-6 transcripts could only be detected in malignant gliomas. In brain metastases, virtually no cytokine gene transcripts could be observed. Surprisingly, TGF-beta transcripts were also detected in all meningiomas. Thus, transcription of genes encoding for inhibitory factors appears to prevail in primary brain neoplasms.

Adolescent↗

PubMed1993

Effects of different culture protocols on the expression of discrete T-cell receptor variable regions in human tumour infiltrating lymphocytes.

Therapeutic effects of tumour infiltrating lymphocytes (TIL) rely on T-cell receptor (TCR) engagement. In this work, the expression of five TCR alpha/beta variable (V) domains was quantitatively analysed by means of a panel of monoclonal antibodies (Mab) recognising gene products from TCR V alpha 2, V beta 5, V beta 6, V beta 8 and V beta 12 families in freshly isolated TIL and in autologous peripheral blood mononuclear cells (PBMC) from patients with neoplasms. In 3 out of 6 cases, differences in the expression of V beta 5, V beta 6, V beta 8 or V beta 12 could be detected. TIL populations were expanded by using recombinant human interleukin-2 (rhIL-2) alone or in addition to solid phase bound anti-CD3 Mab. Cultured TIL showed similar CD4/CD8 ratios and cytotoxic activity against autologous neoplastic target cells, regardless of the activation protocol. In 4 patients, the expression of TCR alpha/beta V gene products, as compared with TIL from freshly excised tumours, was found to be modified in cultured TIL, especially in cell populations activated with rhIL-2 only. These results indicate that TCR V gene usage in TIL may quantitatively differ from that in PBMC. TIL culture protocols using rhIL-2 alone or in combination with solid phase bound anti-CD3 may result in differential expression of discrete TCR V families.

Aged↗

PubMed1993

Antibiotic prophylaxis with two doses of cephalosporin in patients managed with internal fixation for a fracture of the hip.

A prospective, randomized, double-blind study was performed to evaluate the effects of antibiotic prophylaxis on the development of a wound infection in 239 patients who had immediate stabilization of a fracture of the proximal part of the femur with a dynamic hip screw. The effects of two perioperative doses of cefotiam, given twelve hours apart, were compared with those of two doses of a placebo. Sixteen perioperative risk factors were evaluated to determine whether it was possible to identify patients who were at risk for a wound infection. All patients were followed for a minimum of six weeks. Antibiotic prophylaxis significantly reduced the prevalence of wound infection (p < 0.05): the rate of major wound infection decreased from 5 to 1 per cent and the rate of minor wound infection, from 11 to 4 per cent. The most powerful predictors of major wound infection were the duration of the operation, the interval between the accident and admission to the hospital, and the duration of postoperative urinary catheterization. The preoperative level of serum albumin and the absolute lymphocyte count were significant predictors (p < 0.05) of minor wound infection and systemic infection, respectively.

Aged↗

PubMed1993

T-cell receptor V-gene usage in neoplasms of the central nervous system. A comparative analysis in cultured tumor infiltrating and peripheral blood T cells.

The use of tumor-infiltrating lymphocytes in the treatment of central nervous system (CNS) neoplasms has met with serious obstacles due to difficulty of culture and poor characterization. Since in other tumors the therapeutic effects of tumor-infiltrating lymphocytes have been shown to rely on T-cell receptor engagement, the authors addressed the question as to whether expression of T-cell receptor variable (V) domains in cultured tumor-infiltrating lymphocytes from CNS is different from that of autologous cultured peripheral blood mononuclear cells. Infiltrating lymphocytes from CNS neoplasms, including primary malignancies, metastatic cancers, and meningiomas, were cultured in the presence of interleukin-2 and anti-CD3 monoclonal antibodies (MoAb's) in order to obtain optimum growth of T cells. Autologous peripheral blood mononuclear cells from the same patients were similarly cultured. After 4 to 5 weeks of culture, 97.3% +/- 2.6% (mean +/- standard deviation) of the resulting cell populations were CD3-positive lymphocytes. The expression of T-cell receptor V domains was then studied by using a panel of 12 MoAb recognizing gene products from T-cell receptor V-alpha 2, V-beta 5, 6, 8, and 12, V-gamma 4 and 9 families, and from two subfamilies of V-delta 2. Remarkably, in over 70% of all paired measurements, percentages of T cells expressing discrete T-cell receptor V-gene products were found to be virtually identical in tumor- and peripheral blood-derived cultured cell populations, with differences never exceeding 1%. In contrast, a different expression of individual V-gene products, concerning both alpha/beta and gamma/delta T-cell receptors, could be detected between cultured tumor-infiltrating lymphocytes and autologous peripheral blood-derived T lymphocytes in seven of 12 patients. In two cases, significant differences between the two populations were also observed in the proliferative responses obtained upon stimulation with staphylococcal enterotoxins that trigger defined V-beta T-cell receptors. Altogether, these data suggest that the T-cell receptor repertoire of cultured tumor-infiltrating lymphocytes from CNS tumors, suitable for use in adoptive immunotherapies, differs from that of autologous cultured peripheral blood mononuclear cells.

Adult↗

PubMed1993

[Quality control and cost-benefit analysis in surgical fracture treatment].

In recent years quality assurance is gaining increasing importance in all parts of medicine. In this article, different quality control measures in the field of operative fracture treatment are reviewed and illustrated. As in most other therapeutic specialties, the most commonly used measures are sporadic quality control studies. The Documentation Center of the association for the study of internal fixation [AO] offers in addition to all its contributing clinics an extraordinary measure for a continuous control of their treatment results. So far only a few instances of cost-benefit analysis have been published. Besides direct comparison of costs of different treatment options, improved quality of life may be calculated as well, using the method of Quality-Adjusted Life Years [QALY].

Cost-Benefit Analysis↗

PubMed1993

[Quality of emergency admission (resuscitation, REA) and first aid in multiple trauma].

Undue delay between hospital admission and the beginning or urgent operative procedures is considered as a major mortality risk for polytraumatized patients in any trauma center. As part of a quality control study at our institution (Kantonsspital, University of Basel), the time spent for early resuscitation and diagnostic procedures was therefore prospectively recorded in 20 patients (mean age 38 years) with a mean ISS of 26.9 (range: 13 to 43). Time spent in the resuscitation room averaged 31.4 min (range: 10 to 50 min). Conventional radiographic diagnostic procedures took 34.7 more min (range: 20 to 60 min). An additional CT scan was performed in 15 patients requiring 19.5 min per region (head/thorax/abdomen/spine). Four patients underwent angiography necessitating 28 more min (mean). Time elapsed between admission and arrival of the patient in the OR or the ICU respectively accounted for an average of 89 min (range 22 to 200 min). For comparable injury severities this interval was shorter during the day than during the night (77 and 103 min respectively). Diagnoses established during this period were both accurate and comprehensive, as detectable from the low rate of missed diagnosis (three minor fractures). Although our results match favorably with figures reported in the literature we feel that further improvements could be achieved by performing the conventional radiographic procedures simultaneously with the early resuscitation in the resuscitation room. At present time, for reasons of X-ray protection, this is not possible in our institution.

Adolescent↗

PubMed1993

[Experience with the AO universal femoral intramedullary nail for management of femur shaft fractures].

57 fractures of the femoral shaft, treated with an AO femoral interlocking nail, have been analysed in a retrospective study. 40 nails have been implanted primarily, 17 as secondary procedures following different operations. In the group of primary nailing 35/40 reached a good or very good result, 8 of them however, following secondary operations. In the group of the secondary nailing, 9/17 patients had a good or a very good result. 3 pseudarthroses persisted. The AO femoral interlocking nail therefore appears to be an adequate implant for the treatment of femoral shaft fractures, but a precise implantation technique is a prerequisite for the successful outcome.

Bone Nails↗

PubMed1993

[The AO universal femur intramedullary nail: problems and their amelioration. Retrospective quality control study of 57 femur shaft fractures].

Today intramedullary nailing is considered the treatment method of choice in fractures of the femoral diaphysis. In this retrospective quality control study 57 femoral fractures treated with the AO-Universal Femoral Nail have been reviewed. The average follow up time was 2.9 years. Intramedullary nailing was done as a primary procedure in 40 cases and in 17 cases as a secondary procedure following various initial operations. The results were evaluated according to the Stromsoe score. 27 of the 40 primary procedures went on to an uneventful healing and showed good to excellent final result. Technical errors (7), non-unions (4) and 1 deep infection required various secondary procedures. Thereafter the final number of good to excellent results amounted to 35 out of 40 patients. In the group with secondary i.m. nailing 9 out of 17 patients showed a good to excellent final result. 2 non unions persisted. In conclusion the AO-Universal Femoral Nail proved to be suited for the treatment of femoral shaft fractures for both primary and secondary procedures. In this series, however, technical imperfections led to a high rate of secondary procedures. Strict observation of the recommended operative technique is therefore mandatory.

Adolescent↗

PubMed1993

[Modification of ischemia and reperfusion damage of skeletal muscles with allopurinol: in vivo 31P MR spectroscopy of the posterior limb of the rat].

The effect of Allopurinol on energy metabolism (re-utilisation of hypoxanthine) was studied in a in vivo skeletal muscle ischemia rat model by 31-P-MR spectroscopy. Allopurinol-treatment showed no benefit to the kinetics of PCr/(Pi + PCr) and ATP/(Pi + PCr). The role of re-utilisation of hypoxanthine has to be further investigated.

Adenosine Triphosphate↗

PubMed1993

[Proximal femoral fractures: trochanteric area (classification 31 A1-A3)].

The increasing incidence of trochanteric fractures renders their treatment a challenging task concerning both medical and increasingly socio-economical questions as well. The majority of these fractures occurs in elderly patients compromised by various preexisting medical problems. The primary goal of treatment therefore has to be early mobilisation to avoid secondary complications. This can only be achieved by operative treatment. Regarding the perioperative management an antibiotic as well as an antithrombotic prophylaxis is advisable. Recent data also suggest to add an enteral nutritional supplement during the postoperative period. The social reintegration depends however primarily upon the rapid restoration of the walking capacity. In this concern the Dynamic Hip Screw (DHS) is an optimal implant for ORIF, since it allows early full weight-bearing and shows a lower complication rate than static implants (e.g. the condylar blade plate).

Aged↗

PubMed1993

[The dynamic hip screw support plate for management of unstable proximal femoral fractures].

The DHS-Implant system is a technically simple and widely used operative treatment modality for pertrochanteric fractures of the femur. In unstable 4 part-fractures rotation of the head and neck fragment around the lag screw and a significant impaction might lead to a lateralisation of the greater trochanter and therefore to an important shortening. To prevent these effects we treated 17 patients with 4 part-fractures with a prototype of a modular trochanteric DHS buttress plate. With this additional implant the lateralisation of the greater trochanter could be prevented in all cases. This also leads to a limitation of the telescoping, with less shortening even with immediate full weight bearing.

Adult↗