Transfected rat islet tumour cells express mouse major histocompatibility complex class I antigens functionally

Summary Rat insulinoma cells clone 5AH-B, were transfected by electroporation with the gene encoding the mouse major histocompatibility complex class I antigen H-2K^b, whereupon stable transfectants were selected and analysed. Data from flow cytometric analyses using three different H-2K^b specific monoclonal antibodies and functional assays using H-2K^b specific alloimmune cytotoxic T cells revealed that the encoded H-2 antigen was expressed in a functional manner. Similar experiments employing the monoclonal antibody OX-18, which recognizes rat major histocompatibility class I molecules, and xenoimmune cytotoxic T cells specific for the endogenously expressed RT1^g antigen showed that functional expression of the RT1^g antigen was maintained. However, a down-regulation of the expression was observed in H-2K^b positive transfectants, whereas normal expression was retained in K^b negative transfectants. The function of the native promoters of both the endogenous and the transfected class I genes was found to be preserved in the transfectants as assessed by the response to stimulation with interferon-. The present study was unable to confirm the reports of RIN specific lysis by T cells from multiple low dose streptozotocin diabetic mice. Even in the presence of the syngeneic restriction element no lysis was observed. We conclude, that rat insulinoma cells clone 5AH-B, are able to integrate a foreign class I antigen gene and express the encoded product functionally. The data also suggest the possibility of creating major histocompatibility antigen positive rat insulinoma cells which are RT1^g negative. Such transfectants will be of great potential value for the dissection of cell mediated B cell destructive processes.     

Studies of the mechanism of tolerance induced by short-term immunosuppression with cyclosporine in high-risk corneal allograft recipients. I. Analysis of CTL precursor frequencies

Transplantation of unmatched allogeneic corneas into highly vascularized recipient eyes under the cover of short-term immunosuppression with cyclosporine enables permanent engraftment. The aim of this study was to further elucidate the mechanism(s) underlying this tolerant state. In eight "high-risk" cornea recipients the clone sizes of donor-specific and third-party reactive cytotoxic T cell precursors were assessed by limiting dilution analyses before and at three and six months after transplantation. Acquired allograft tolerance in these patients was not accompanied by clonal reduction of donor-specific CTL-p, whereas in the case of an irreversible rejection the donor-specific CTL pool size was significantly enlarged. This donor-specific CTL-p increase could already be seen two months before clinical manifestation. These patterns differed from that of tolerant renal transplant patients, in whom marked and donor-specific reduction of CTL-p was observed. During rejection identical patterns with increasing donor-specific CTL-p frequencies were seen in both groups of patients. We conclude that induction of tolerance by short-term CsA to unmatched cornea grafts is not caused by clonal reduction of the effector precursor cell pool.     

A different desensitization pattern of cardiac beta-adrenoceptor subtypes by prolonged in vivo infusion of isoprenaline

(-)Isoprenaline was continuously administered to rats at a rate of 0.4 mg/kg/h for 7 days via subcutaneously (s.c.) implanted osmotic minipumps. This treatment induced cardiac hypertrophy and a marked decrease in basal as well as catecholamine-stimulated adenylate cyclase activity in a ventricular plasma membrane fraction. The total number of beta-adrenoceptors was downregulated by one-half the amount of the receptor sites obtained in a control group. However, in the isoprenaline-treated group, the beta 2-adrenoceptors constituted a significantly smaller proportion of the total beta-adrenoceptor population (28%) than in the control group (50%). Transformation of these relative into absolute values indicates that prolonged isoprenaline treatment induced a significantly higher downregulation of beta 2- than of beta 1-adrenoceptors. The fact of a different beta-adrenoceptor desensitization pattern in response to in vivo administration of nonselective beta-adrenergic agonists therefore must be taken into consideration when desensitization is used as a method for determination of subtype selectivity of an agonist per se. However, we were unable to detect the "lost" beta-adrenoceptors in a light vesicular fraction. In our study, this fraction was not separable from plasma membranes, as substantiated by levels of plasma membrane markers as high as in the plasma membrane fraction and by a guanine nucleotide-dependent adenylate cyclase activity.     

CD97, but not its closely related EGF-TM7 family member EMR2, is expressed on gastric,pancreatic, and esophageal carcinomas

CD97 expression is related closely to the dedifferentiation and tumor stage in thyroid carcinomas. We systematically examined the role of CD97 and its closest relative, EMR2, in normal and malignant gastric, esophageal, and pancreatic tissue. The normal tissues were EMR2-, whereas CD97 was expressed slightly in the parietal cells of gastric mucosa and in exocrine pancreatic cells. Interestingly, intralobular and interlobular pancreatic ducts were CD97+. All tumors were EMR2-. CD97 was expressed by 44 of 50 gastric, 14 of 18 pancreatic, and 10 of 13 esophageal carcinomas. Of the 44 gastric cancers, 27 showed disseminated or scattered tumor cells at the invasion front with stronger CD97 expression than tumor cells located in solid tumor formations. There was no correlation between CD97 levels in the tumors or soluble CD97 in the serum samples and the clinicopathologic features of the patients. Taken together, significant numbers of gastric, esophageal, and pancreatic carcinomas are CD97+, whereas its homolog, EMR2, does not have any role in such tumors.     

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Ohne Zusammenfassung     

Proteases and antiproteases related to the coagulation system in plasma and ascites — An approach to differentiate between malignant and cirrhotic ascites

Summary The concentrations of several proteases and antiproteases known to be present in ascites were tested in plasma and ascitic fluid with regard to their ability to separate ascites according to malignant or nonmalignant disease. Seventeen patients with proven malignant ascites and 37 with ascites due to liver cirrhosis were included. Activities of plasminogen, ₂-antiplasmin, antithrombin-III, and factor V, and the concentration of ₁-protease inhibitor were significantly higher in the plasma of patients with malignant ascites than in cirrhotic patients. Fibronectin, plasminogen, ₂-macroglobulin, ₁-protease inhibitor, antithrombin-III, and albumin revealed higher concentrations or activities in malignant ascites than in cirrhotic ascites. Due to a wide variation of most parameters, only fibronectin, antithrombin III, and ₁-protease inhibitor in ascites had a sensitivity and specificity higher than 90% for malignant ascites. When the specific protein/albumin ratio was used, only the accuracy of fibronectin was increased reaching a sensitivity and specificity of 100%. The plasma/ascites gradients of the proteins assessed differed significantly, that of fibronectin being much higher (22±7) than that of all other proteins. In malignant ascites fibronectin concentration was only correlated with ₁-protease inhibitor concentration but not with the concentration or activity of all other proteins, while in cirrhotic ascites most proteins revealed a positive correlation.The determination of the fibronectin concentration or the fibronectin/albumin ratio in ascites can differentiate malignant and nonmalignant ascites. All other proteases and antiproteases assessed are of lesser value for this purpose, although most are significantly increased in ascites and plasma of patients with malignant disorders.Abbreviations ₂AP ₂-Antiplasmin - ₁PI ₁-Protease inhibitor - AT III Antithrombin III - FDP Fibrin(ogen) degradation products - FM Fibrin monomers - ₂MG ₂-Macroglobulin - PTT Partial thromboplastin time - RT Reptilase time     

Intensivtherapie und Prognose des akuten Kreislaufstillstandes

Zusammenfassung Anhand von 115 im Zeitraum von 2 1/2 Jahren beobachteten Episoden von akutem Kreislaufstillstand bei 90 Patienten werden die Kriterien und Behandlungserfolge der Intensivtherapie des akuten Kreislaufstillstandes dargelegt. Während die Basis-Therapie mit externer Herzmassage, künstlicher Beatmung, Natriumbicarbonatinfusionen und elektrischer Defibrillation eindeutig feststeht, bietet die medikamentöse Führung noch immer Probleme. Zehn eigene Verlaufsbeobachtungen zeigen, daß betaadrenergische Sympathomimetica auch bei bestimmten Fällen tachysystolischer Herzrhythmusstörungen günstig wirken. Der Versuch der elektrischen Stimulation des Herzens mit einer extern angelegten epikardialen Schrittmachersonde bei akutem Kreislaufstillstand durch Asystolie oder Bradykardie führte in keinem von 8 Fällen zum Erfolg. Für die Früh- und Spätprognose sind bei adäquater Therapie in erster Linie Art und Schwere des Grundleidens sowie der morphologisch funktionelle Zustand lebenswichtiger Organe bei Einsetzen des plötzlichen Kreislaufstillstandes verantwortlich. Bei Kammerflimmern und Kammerflattern waren deutlich bessere Resultate zu erzielen, als beim akuten Kreislaufstillstand durch Asystolie. Von den 90 Patienten überlebten 12 länger als 4 Wochen (13%), 9 (10%) konnten entlassen werden und sind zum Zeitpunkt der Publikation ohne Nachwirkungen des akuten Kreislaufstillstandes. Es wird auf die Bedeutung einer lückenlosen Beobachtung Schwerstkranker und die Beachtung prämonitorischer Zeichen zur Verhütung des akuten Kreislaufstillstandes hingewiesen.

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Summary Criteria and therapeutic success of intensive therapy of cardiac arrests are evaluated in 115 episodes observed in 90 patients over a period of 2 1/22 years. While basic therapy with external cardiac massage, artificial ventilation, infusion of sodium bicarbonate and electrical defibrillation is generally agreed upon, the choice of further drugs is still problematic. It is shown in 10 cases that under certain conditions even in ventricular fibrillation and ventricular tachycardia beta-receptor stimulating drugs are indicated. Electrical stimulation of the heart by an external epicardial pacemaker was unsuccessful in all of eight cases with complete asystoly or bradycardia. Immediate and long term results of cardiac arrests with adequate treatment primarely depends on the extend of the underlying disease as well as on the condition of all vital organs at the time of onset of the arrest. Ventricular fibrillation and -flutter had a better prognosis than asystoly. Twelve out of the ninety patients lived longer than four weeks after the arrest (13%). Nine of these are still living at the time of publication with an observation time from three months to two years. The chance of improving therapeutic results with intensive care lie mainly in preventing rather than curing complications such as cardiac arrests.

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Professor Dr.H. E. Bock zum 65. Geburtstag.     

Analysis of microdissected prostate tissue with ProteinChip arrays--a way to new insights into carcinogenesis and to diagnostic tools

Prostate carcinomas are one of the most common malignancies in western societies. The pathogenesis of this tumor is still poorly understood. These tumors present with two characteristic features: epithelial-mesenchymal interactions, which play a pivotal role for tumor development and most of clinically manifest cancers arise in prostate proper compared to a minority of tumors which develop in the transitional zone. Deciphering the epithelial-mesenchymal cross talk and identification of molecular pecularities of the sub-populations of cells in different zones can therefore help understanding carcinogenesis and development of new, non-invasive tools for the diagnosis and prognosis of prostate carcinomas which has remained a challenge until today. A ProteinChip array technology (SELDI = surface enhanced laser desorption ionization) has been developed recently by Ciphergen Biosystems enabling analysis and profiling of complex protein mixtures from a few cells. This study describes the analysis of approximately 500-1000 freshly obtained prostate cells by SELDI-TOF-MS (surface enhanced laser desorption ionization time-of-flight mass spectrometry). Pure cell populations of stroma, epithelium and tumor cells were selected by laser assisted microdissection. Multiple specific protein patterns were reproducibly detected in the range from 1.5 to 30 kDa in 28 sub-populations of 4 tumorous prostates and 1 control. A specific 4.3 kDa peak was increased in the prostate tumor stroma compared to normal prostate proper and transitional zone stroma and increased in prostate tumor glands compared to normal prostate proper and transitional zone glands. Coupling laser assisted microdissection with SELDI provides tremendous opportunities to identify cell and tumor specific proteins to understand molecular events underlying prostate carcinoma development. It underlines the vast potential of this technology to better understand pathogenesis and identify potential candidates for new specific biomarkers in general which could help to screen for and distinguish disease entities, i.e. between clinically significant and insignificant carcinomas of the prostate.