[Success factors in hospital administration].
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Cost-Benefit Analysis↗
Biomedical subjects
M Heberer
Publications and source records attributed to M Heberer.
Nonreplicating recombinant vaccinia virus encoding human B-7 molecules elicits effective costimulation of naive and memory CD4+ T lymphocytes in vitro.
We constructed recombinant vaccinia viruses (recVV) encoding the human T-cell costimulatory molecules B7-1 and B7-2. To abrogate the vaccinia virus transcription termination signal for early genes, the cDNA of B7-1 had to be modified by a T through C sense mutation at position 766. Upon infection with replication incompetent and noncytopathic recVV, several tumor cell lines as well as cultured human fibroblasts expressed the costimulatory molecules. All these cells were capable of providing effective costimulation for proliferation of resting CD4(+) T-cells after infection with recVV encoding B7 molecules. The costimulatory effect could be blocked with CTLA-4 IgG fusion protein, the soluble ligand for B7. RecVV-induced overexpression of B7 on syngeneic EBV-transformed lymphoblastoid B-cells was able to costimulate the proliferative response of CD4(+) memory cells against VV antigens. The possibility of easily engineering a variety of human cells using recVV encoding human B7 molecules holds implications for the future design of vaccination strategies.
B7-1 Antigen↗
Functional and morphological outcome of knee joint transplantation in dogs depends on control of rejection.
BACKGROUND: The reconstruction of massive osteochondral defects extending to weight-bearing joints remains a surgical challenge. Total knee joint transplantation has been performed experimentally, but these studies lacked prospective evaluation of functional outcome, graft vascularization, and graft viability. METHODS: Replantation and transplantation of vascularized knee joints was performed in dogs (n=4 per group), comparing functional and morphological results during a 6-month follow-up. RESULTS: All replant recipients and three transplant recipients survived the 6-month follow-up period. At this time, duplex sonography and angiography revealed patent anastomoses in all animals. Increases in volumetric flow rates and vascular collateralization were observed in allografts, as compared with replanted joints (100+/-16 ml/min vs. 31+/-15 ml/min at 6 months after transplantation). Bone fusion at the graft-host interface was verified by fluorography in all animals at 3 months after transplantation. Six months after transplantation, microradiographies and computerized tomographies revealed spongialization of the cortical bone and filling of the medullary space by trabecular bone in transplanted joints. Such alterations were not detectable in replanted joints. Chondrocyte viability exceeded 80% in all but one transplanted joint. Lymphocyte infiltration of synovia and arterial walls was detected in all transplanted joints, suggesting the presence of chronic rejection. Weight-bearing capacity recovered in all replanted animals (weight-bearing index before transplantation: 0.499+/-0.080; 6 months after transplantation: 0.38+/-0.16) but only in two of four transplanted animals (weight-bearing index 6 months after transplantation: 0.37, 0.28, and 0.00). CONCLUSIONS: These data demonstrate the potential of joint grafting and the critical dependence of allotransplantation on the control of rejection.
Angiography↗
High expression of MAGE-3 protein in squamous-cell lung carcinoma.
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Adult↗
Generation of tumoricidal cytotoxic T lymphocytes from healthy donors after in vitro stimulation with a replication-incompetent vaccinia virus encoding MART-1/Melan-A 27-35 epitope.
Active specific immunotherapy targeting tumor-associated antigens (TAA) requires reagents of high immunogenicity and safety. To address this issue, we constructed a recombinant vaccinia virus carrying a minigene insert encoding the HLA-A2.1-restricted MART-1/Melan-A27-35 melanoma TAA (rVV-M). To facilitate the entry of the antigenic epitope into the endoplasmic reticulum, a sequence coding for adenovirus E3/19K leader peptide was added. This rVV-M was made replication-incompetent by treatment with psoralen and UV light. Infection with rVV-M rendered HLA-A2.1 EBV-transformed lymphoblastoid cells sensitive to the cytotoxic effects of HLA-class-1-restricted, MART-1/Melan-A27-35-specific cytotoxic T lymphocytes (CTL). The capacity of rVV-M to generate HLA-A2.1-restricted MART-1/Melan A-specific CTL was demonstrated from tumor-infiltrating-lymphocyte (TIL) cultures and from healthy donors' peripheral-blood mononuclear cells (PBMC). MART-1/Melan-A27-35-specific CTL were generated from TIL after 2 weekly stimulation courses. Infection with rVV-M elicited a higher CTL response than addition of exogenous peptide, whereas, when a similar protocol was used to stimulate PBMC of healthy donors, significant and specific cytotoxic activity could be observed only upon rVV-M infection but not upon exogenous peptide addition. All CTL generated upon rVV-M stimulation were also able to efficiently kill melanoma cell lines expressing both MART-1/Melan-A and HLA-A2.1. In addition, TNF-alpha production could be induced in rVV-M-stimulated CTL upon co-culture with COS-7 cells transiently transfected with MART-1/Melan-A and HLA-A2.1 genes. This safe and highly immunogenic reagent could be of use in TAA-targeted clinical immunotherapy.
Amino Acid Sequence↗
[Tumor cachexia--a special entity and therapeutic sequelae].
Cancer cachexia as a syndrome of generalized host tissue wasting results from interactions of tumor, host and tumor-directed treatment. Cancer cachexia may be associated with all terminal cancer stages and is not tumor-specific. Weight loss, functional impairment and deterioration of the quality of life require palliation. A therapeutic algorithm based on therapeutic standards is proposed: appropriate use of parenteral and enteral nutrition, of progesterone analogues and of metoclopramide. Innovative concepts that may enable prophylactic rather than therapeutic interventions are currently under investigation.
Cachexia↗
Increased surface expression of CD18 and CD11b in leukocytes after tourniquet ischemia during elective hand surgery.
The surface expression of beta2-integrins was investigated in leukocytes from patients undergoing ischemia induced by tourniquet application for elective hand surgery. Blood samples were obtained before initiation, at the end of ischemia, and after 15 minutes of reperfusion from ischemic and contralateral arms of five patients. Comparable expression of CD18, CD11a, CD11b, and CD11c could be detected by immunofluorescence in leukocytes from samples drawn from either arm before tourniquet application. In contrast, a significant increase in the expression of CD18 was detectable in monocytes, granulocytes, and lymphocytes from the ischemic arm compared with that in the nonischemic contralateral control, at the end of the ischemia time (80 +/- 16 minutes). A significantly increased expression of CD11b, but not CD11a or CD11c, determinants was also observed in granulocytes and monocytes. Concomitantly, a significant reduction in the percentages of granulocytes in samples from ischemic areas was detectable. After 15 minutes of reperfusion, differences in the expression of these adhesion molecules were no longer significant. The expression of the genes encoding interleukins IL-1alpha, IL-1beta, and IL-6 and tumor necrosis factor alpha (TNFalpha) proinflammatory cytokines was also studied by reverse polymerase chain reaction (rPCR) in peripheral blood mononuclear cells (PBMCs) obtained from the same samples in three patients. IL-1beta or IL-6 gene expression was never observed. Expression of IL-1alpha and TNFalpha genes, as detected in two patients, was not related with induction of ischemia. However, in these patients expression of one or both these genes was observed in samples derived from the ischemic but not the control arm after 15 minutes of reperfusion. These data document that overexpression of adhesion molecules and sequestration of leukocytes take place following short ischemia times, as routinely applied clinically for minor surgical procedures.
Adult↗
Kinetics of high-energy phosphates in allopurinol-pretreated ischaemic and post-ischaemic skeletal muscle: an in vivo magnetic resonance spectroscopy study.
Allopurinol (AP) protects skeletal muscle function against ischaemia-induced injury, but the mechanism is not yet clear. As AP acts as a competitive xanthine oxidase inhibitor, both a reduction of oxygen-derived free radicals and an enhancement of purine resynthesis (salvage pathway) might be involved. We investigated the in vivo kinetics of high-energy phosphates in skeletal muscle after AP pretreatment using 31P-magnetic resonance spectroscopy during 2 h of ischaemia and 3 h of reperfusion in rat hindlimbs. Three animals (group A) were pretreated with a total of 160 mg/kg AP i.p., 3 control animals (group B) received the same amount of 0.9% saline solution. ATP decreased to 18.6 +/- 1.3% of the pre-ischaemic value in group A and to 17.3 +/- 2.8% in group B after 2 h of ischaemia, and rose to only 47.7 +/- 1.5 and 50.5 +/- 1.8%, respectively, after 3 h of reperfusion. Phosphocreatine fell to 7.2 +/- 2.9 and 7.6 +/- 2.2% of pre-ischaemic values after 2 h of ischaemia and rose again to 36.5 +/- 12.9 and 45.4 +/- 20.4% after 3 h of reperfusion. Inorganic phosphate (Pi) increased 5-fold after 2 h of ischaemia, irrespective of the treatment. After 3 h of reperfusion, Pi was still 4 times the pre-ischaemic value. The kinetics of ATP, PCr, and Pi levels were not statistically different between the two groups. These results indicate that the ATP salvage pathway does not play an important role in AP-induced attenuation of ischaemia/reperfusion-induced muscle damage.
Adenosine Triphosphate↗
Heterogeneity of melanoma antigen-1 (MAGE-1) gene and protein expression in malignant melanoma.
OBJECTIVE: The authors' objective is to identify MAGE-1 tumor antigen in clinical melanoma specimens and to verify the extent of its expression in tumors where evidence of specific gene transcripts can be obtained. BACKGROUND DATA: The MAGE-1 gene encodes a tumor-associated antigen that can be recognized by specific cytotoxic T lymphocytes. Transcription of the MAGE-1 gene has previously been demonstrated in various malignancies, but the production of the specific gene product and its distribution in neoplastic tissues have not yet been addressed. METHODS: Total cellular mRNA was extracted from six melanoma biopsies, reverse-transcribed and tested in 25-45 cycles of reverse polymerase chain reaction (rtPCR) in the presence of primers' pairs specific for the beta-actin-positive control gene and for the MAGE-1-encoding gene. Concurrently, portions of these specimens were lysed and probed for MAGE-1 protein by immunoblotting. Additional material from the same biopsies was analyzed following immunohistological staining with MAGE-1-specific monoclonal antibodies. RESULTS: MAGE-1 gene transcription could be demonstrated following 25 cycles of rtPCR in one out of six biopsies and in three more following 35 cycles of rtPCR. 2/6 samples were negative even after 45 cycles of rtPCR. MAGE-1 protein production could be detected by immunoblotting in the lysates from biopsies showing evidence of specific gene transcription. Cells positive for MAGE-1 protein expression could be identified by immunohistochemistry on snap-frozen sections in three of the four tumors displaying specific transcripts. Distribution of positivity ranged between focal cellular areas and single positive cells in the different tumors. CONCLUSIONS: The MAGE-1 tumor antigen can be detected by specific monoclonal antibodies in clinical tumor specimens. The pattern of positivity observed in samples showing evidence of MAGE-1 gene expression suggests a relevant heterogeneity regarding MAGE-1 antigen production within individual tumor specimens.
Antibodies, Monoclonal↗
Quantitative monitoring of blood supply to knee joint transplants in dogs.
BACKGROUND: Transplantation of vascularized knee joints has become technically feasible, but graft rejection as well as failures of the vascular anastomoses remain critical hazards. We therefore tested the potential of repetitive non-invasive duplex sonography to detect changes of the arterial blood flow following canine knee joint transplantation. METHODS: Four transplantations and, as controls, 4 replantations of intact canine knee joints were performed. The follow-up was 6 months. During this period, repetitive duplex sonography measurements as well as tests of knee joint function were performed. Six months postoperatively, angiographies were performed and all joints were explanted for histological investigation. RESULTS: The luminal diameters of the implanted popliteal artery remained constant in the transplanted animals (preop. 2.6 +/- 0.2 mm, 6 months postop. 2.7 +/- 0.2 mm) but decreased in the autografted controls (preop. 2.9 +/- 0.3 mm, postop. 2.0 +/- 0.3 mm). The time-averaged velocity of the popliteal artery blood flow decreased in both groups 1 month postoperatively. Subsequently, blood flow velocity recovered in transplanted animals but remained low in replanted controls. Significant arterial wall thickening was also detected in transplanted animals as compared to controls. Six months postoperatively, hypervascularization of transplanted joints was confirmed by angiography and thickening of the arterial wall by histology. Furthermore, histology identified mild to chronic allograft rejection in all transplanted joints in spite of controlled cyclosporin A trough level immunosuppression. CONCLUSIONS: Chronic rejection of transplanted vascularized knee joints appears to be associated with vessel wall thickening and hypervascularization rather than with vascular rarefaction (picture of the 'arbre mort') that is characteristic of the rejection of most parenchymatous organs. Duplex sonography appears to be sensitive in detecting the corresponding changes of blood supply.
Angiography↗
[Quality and cost reduction: corresponding goals of strategic reorientation of hospitals].
Industrial quality management has taught that costs are not induced by high quality but by non-quality. The medical literature suggests that this might also hold true in medicine and furthermore reveals factors directed concurrently at lowering costs and at increasing quality: These include personal and institutional case load, implementation of guide lines supported by information technology as well as innovative organizational structures and principles of reimbursement.
Cost Control↗
Cytotoxic T-lymphocyte responses against mutated p21 ras peptides: an analysis of specific T-cell-receptor gene usage.
Generation of cytotoxic-T-lymphocyte (CTL) responses against mutated ras peptides from peripheral-blood mononuclear cells (PBMC) was attempted in a group of HLA-A2.1+ healthy donors. Bulk PBMC cultures were stimulated in vitro with a mixture of peptides encompassing 12 Gly --> Val, 61 Gln --> Lys or 61 Gln --> Leu ras mutations and displaying HLA-A2.1 binding motifs, selected by a computer program. A promiscuous tetanus toxoid peptide was also added. Weekly thereafter, PBMC were re-stimulated with peptide pulsed autologous Epstein-Barr virus (EBV)-transformed B cells. After 8 rounds of re-stimulation, reproducible cytotoxic activity against peptide-pulsed target cells was detectable in one donor. The CTL line recognized 2 nonamers encompassing ras 61 Gln --> Leu mutation. Killing was mediated by CD8+ T cells displaying alphabeta TCR and was inhibited by anti-HLA-A2.1 monoclonal antibodies. No killing of tumor cells expressing the specific mutation could be observed. More than 60 CTL clones were generated. Fine specificity studies revealed effective, though differing cytotoxic activity against both 53-LDILDTAGL-61 and 55-ILDTAGLEE-63, but not against 54-DILDTAGLE-62 mutated peptides, in all but one of the clones. None was able to exert effective cytotoxic activity against tumor cells expressing the specific mutation. T-cell-receptor (TCR) usage was then analyzed phenotypically, by reverse-transcription-polymerase-chain-reaction (RT-PCR) and by sequence analysis. This study revealed the monoclonal nature of the CTL response against mutated nonamers, with TCR expressing Vbeta14 gene product in combination with, Jbeta2.7 and Cbeta2.
Amino Acid Sequence↗
Ischemic preconditioning--a new concept in orthopedic and reconstructive surgery.
The duration of tourniquet-induced ischemia during orthopedic and reconstructive surgery is limited by the risk of ischemia and reperfusion injury to skeletal muscle. This study evaluated the potential of ischemic preconditioning (short periods of ischemia with intermittent reperfusion) to improve skeletal muscle function after ischemia and reperfusion in a rodent model. Preconditioning was found to improve force, contractility, and performance and to decrease fatigue of skeletal muscle. In contrast, energy-rich phosphates, measured concurrently, were not affected by preconditioning, suggesting mechanisms other than energy preservation to be involved. In summary, preconditioning may enable prolongation of orthopedic and reconstructive procedures.
Animals↗
[Ischemic preconditioning in surgery of extremities: experimental studies].
Ischemic preconditioning (IP), using one or more brief periods of ischemia, each followed by a short reperfusion phase, improves tolerance of subsequent sustained ischemia in different organs. The aim of this experimental study was to evaluate the effects of IP on postischemic function in skeletal muscle. Right hindlimbs of anesthetized rats were pretreated with three cycles each of 10 min of ischemia and 10 min of reperfusion (n = 12). Non-preconditioned animals (n = 12) served as controls. These hindlimbs were then subjected to 3 h of ischemia and 2 h of reperfusion. IP resulted in a significant increase in postischemic skeletal muscle force (240 +/- 47 mN vs 409 +/- 63 mN), force-time integral (1081 +/- 242 mN*s vs 2546 +/- 481 mN*s) and endurance (29.6 +/- 3.4 s vs 48.0 +/- 5.0 s). These data support the potential of IP to reduce postischemic skeletal muscle damage in surgery of the extremities using tourniquet ischemia. The concept deserves clinical evaluation.
Animals↗
Nitric oxide-independent inhibitory effects of L-arginine analog NG-monomethy-L-arginine on the generation of interleukin-2 activated cytotoxic activity in humans.
Nitric oxide (NO) derived intracellularly from L-arginine (Arg) is indispensable for optimalgeneration of lymphokine-activated killer (LAK) cell activity in rodents. Still unclear, however, is its role in humans. To address this question human peripheral blood mononuclear cells (PBMC) from healthy donors were cultured in L-arginine free medium supplemented with recombinant interleukin-2 (rIL-2) and in the presence of exogenous L-arginine analog NG-monomethyl-L-arginine (NMMA), a specific inhibitor of the NO synthetic pathway. Cultured PBMC were tested for cytotoxic activity, proliferative capacity, and expression of phenotypic and activation markers (CD3, CD4, CD8, CD16, CD56 and CD25). Culture supernatants were assayed for nitrite (NO2-) and tumor necrosis factor-alpha (TNF-alpha) production. We found that NMMA inhibits the generation of optimal LAK cell activity when no exogenous Arg is supplied. Similar effects were also observed on proliferation, expression of IL-2 receptor induced upon rIL-2 stimulation and on TNF-alpha production. Sodium nitroprusside (SNP), used as a source of exogenous NO could not overcome this effect of NMMA on LAK cell activity. NO2- production was virtually undetectable in culture supernatants. Thus, NMMA affects in an NO-independent manner rlL-2 induced LAK activity in human PBMC.
Journal Article↗
Comparison of cyclosporin A absorption from LCT and MCT solutions following intrajejunal administration in conscious dogs.
Absorption from the intestine of cyclosporin A (CsA), dissolved in either a medium-chain (MCT) or a long-chain triglyceride (LCT) solution, was investigated in a chronic dog model. Following intrajejunal administration of 20 mg of CsA/kg of body weight, absorption, judged by the portalvenous appearance of CsA, was determined by measuring whole blood CsA concentrations in the portalvenous and arterial blood and the portalvenous flow. Appearance of CsA from LCT commenced earlier and attained significantly higher mean peak values (+/- SEM) in the portalvenous blood (2557 +/- 436 ng/mL) than from MCT (274 +/- 80 ng/mL). Portalvenous concentrations of CsA were always higher than arterial concentrations for both LCT and MCT, suggesting that CsA is transported by portalvenous blood following uptake from the gut. Absorption of CsA, measured over 300 min, was 10 times higher with LCT (9.96 +/- 2.00%) than with MCT (0.95 +/- 0.21%). This significant difference is believed to result from the formation of mixed micelles which occurs during digestion of LCT but not MCT.
Animals↗
Effects of verapamil on skeletal muscle function following ischemia and reperfusion.
Verapamil (VRP) improves ischemic tolerance of different organs including brain, kidney, liver and heart. We report here on the effects of preischemic VRP treatment on skeletal muscle function following 3 h of tourniquet ischemia and 2 h of reperfusion using a rodent model. Postischemic and contralateral limbs were evaluated. Fast (musculi peronei)- and slow-twitch muscles (musculus soleus) of both limbs were excised and electrically stimulated in vitro. VRP pretreatment was found to significantly decrease tetanic peak tension of both contralateral nonischemic m. soleus and mm. peronei. Furthermore, VRP improved fatigability of slow-twitch muscles of both ischemic and contralateral limbs [increase of fatigue index from 0.04 +/- 0.009 (0 mg/kg) to 0.10 +/- 0.019 (4 mg/kg)], but not of fast-twitch muscles. These data indicate that the effects of VRP on postischemic skeletal muscle function depend on fiber composition.
Animals↗
Ischemic preconditioning improves post-ischemic skeletal muscle function.
Ischemic preconditioning (IP), using one or more brief periods of ischemia before a sustained ischemia, represents a new approach to reduce tourniquet ischemia-induced skeletal muscle damage. The aim of this study was to investigate the effect of IP on skeletal muscle function and high-energy phosphate tissues levels in a rodent model. IP protocols using one, two, or three preconditioning cycles were compared. IP was found to significantly improve force, performance, endurance, and contractility of postischemic skeletal muscle. The efficacy of IP-induced protection was correlated with the number of preconditioning cycles. Preconditioning with three cycles resulted in a more effective protection as compared to one or two cycles. Three cycles of IP significantly improved force (409 +/- 63 versus 240 +/- 47 mN), performance (2546 +/- 481 versus 1081 +/- 242 mN*sec), endurance (46.7 +/- 5.0 versus 29.6 +/- 3.4 sec) and contractility (59.9 +/- 4.2 versus 38.7 +/- 5.1) in postischemic m.extensor dig. long. when compared to nonpreconditioned muscles. In contrast, high-energy phosphate tissue levels remained unchanged after three cycles of preconditioning. Altogether, this study describes, for the first time, the efficacy of IP to improve postischemic muscle function. The respective clinical potential warrants further exploration.
Animals↗