Injuries of the small and large intestine following blunt abdominal trauma

From 1979 to 1987 1428 patients with blunt abdominal trauma were treated in the Department of Surgery of the University of Freiburg; 119 patients had intestinal injuries. They were mainly young adults who had sustained a car accident. 71.3% of the small bowel injuries were overseen, 14.2% needed resection, and in 14.5% an operative procedure was not necessary. The surgical procedure for colonic injuries has to be chosen with regard to the age and general condition of the patient, to the severity of the trauma, to associated injuries and to the stage of peritonitis. Accordingly, 18% of the patients were treated with and 58% without a protective colostomy, 24% could be treated conservatively. Mortality and morbidity correlated with the severity of associated injuries. Morbidity was also dependent on the time interval between accident and operative therapy.     

Alloplastic ligament replacement. A study of the biological fixation of 5 non-resorbable materials

The long-term stability of alloplastic ligament prostheses depends on various parameters, on including the quality of the biologic fixation in the bone tissue. Biomechanical and histological tests were therefore performed to examine the stability obtained with five different alloplastic and non-resorbable ligament substitute materials following stress-free implantation into the distal femur and proximal tibia of Wistar rats. The materials were: a filament of the PTFE ligament prosthesis, PTFE suture material (Goretex), polyethylene terephthalate (Mersilene), polyethylene (Braun-Dexon) and polybutylene terephthalate (Miralene). The materials used were all of USP-1 quality. Extraction trials of the implants 32 weeks later did not show any differences between the PTFE materials, such as polyethylene and polyethylene terephthalate, whereas a significantly lower value was found for polybutylene terephthalate. The fixation involved connective tissue exclusively with all the materials tested except for PTFE. PTFE not only induced tight and direct bony contact externally, within the material itself extensive formation of new bone was also found. PTFE was found to be the most histocompatible material, while polyethylene terephthalate led to the most pronounced foreign-body-type reactions.     

The repertoire of HLA-Cw-specific NK cell receptors CD158 a/b (EB6 and GL183) in individuals with different HLA phenotypes.

Over the last few years, natural killer (NK) cells have been shown to express major histocompatibility complex (MHC) molecules recognizing receptors that are thought to function primarily as negative signalling receptors. Much attention has been focused on the NK cell receptors CD158a (EB6) and CD158b (GI 183), which recognize two alternative epitopes on the HLA-Cw locus. In order to investigate whether HLA type affects the CD158a/b repertoire, expressed as percentage positive cells for a particular receptor and mean expression on this population of NK cells, peripheral blood lymphocytes of 47 HLA-typed donors were examined. Peripheral blood samples were examined by flow cytometric analysis to investigate the expression of CD158a and CD158b receptors on the surface of NK cells. In parallel, we determined each individual's HLA phenotype. There was a great heterogeneity in CD158 expression; nevertheless all individuals had NK cells belonging either to the CD158 a+b-, a-b+ or a-b- populations. No positive or inverse correlations could be shown between either receptor expression intensity or proportion of positive cells, and presence of the appropriate ligand. Thus no association between an individual's NK receptor repertoire and HLA serotype could be demonstrated. It is concluded that CD158 is expressed on NK cells in a highly redundant fashion. Our data do not support either a positive selection mechanism or the receptor calibration model.     

In-vivo evaluation of random donor platelet concentrates from pooled buffy coats

 Random-donor platelet concentrates (PC) prepared from pooled buffy coats have recently been described as an alternative method for platelet preparation. We evaluated such PCs in the clinical setting compared with a standard PC from platelet apheresis. PCs were prepared either from pools of buffy coats (BC-PC) or from single donors (SD-PC) with the cell separator CS-3000 plus. PCs were stored for up to 5 days before transfusion. We compared fresh PC (day 1) with stored (day 2–3) and long-stored PC (day 4–5). For analysis, platelet increment in the recipient was determined immediately and 16–22 h (mean 20 h) after transfusion, corrected for total body area and transfused platelets (CCI). A total of 316 PCs were administered to 36 thrombocytopenic patients suffering from various hematological disorders. Patients with detectable HLA or platelet-specific antibodies or splenomegaly were excluded from the study. Mean platelet content of the PC was 262×10⁹ for BC-PC and 251×10⁹ for SD-PC. The 20-h CCI after transfusion of fresh PC was slightly higher with BC-PC than with SD-PC (14.5 versus 11.9;p=0.19), but values did not differ significantly between the two types of PC on any day of storage. For BC-PC, 20-h CCI decreased with further storage by 30% (10.2;p=0.02). For SD-PC a decrease by 9% was not significant. In conclusion, platelet concentrates prepared from pools of buffy coats showed excellent transfusion results when administered fresh, but storage decreased the CCI by 30%. No significant difference from PCs from plateletpheresis was observed on any day of storage. Both types of platelet concentrates were capable of sufficient platelet increment even when stored for up to 5 days. Received: 28 December 1995 / Accepted: 14 May 1996     

LPS resistance in monocytic cells caused by reverse signaling through transmembrane TNF (mTNF) is mediated by the MAPK/ERK pathway

The transmembrane form of tumor necrosis factor (mTNF), expressed on activated monocytes (MO) and macrophages (MPhi), is able to induce apoptosis in human endothelial cells (EC). Apoptosis is mediated by two distinct mechanisms: direct cell contact and a yet-unidentified soluble protein, death factor X. In addition, mTNF acts as a receptor that transduces a "reverse signal" into MO/MPhi when bound to the TNF receptor on EC. Reverse signaling by mTNF confers resistance to bacterial lipopolysaccharide (LPS). Stimulation of reverse signaling by mTNF blocks the ability of MO/MPhi to produce death factor X and proinflammatory cytokines. We have investigated which signaling pathways are used by mTNF acting as receptor. Reverse signaling triggers two independent pathways that can be distinguished by protein kinase C (PKC) inhibitors. The suppression of LPS-induced death factor X is dependent on PKC, whereas the suppression of LPS-mediated cytokine release is not. LPS and reverse signaling stimulate the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway. It is interesting that the activation of reverse signaling by mTNF renders MO/MPhi refractory to a subsequent activation of the MAPK/ERK pathway by LPS. Thus, reverse signaling achieves LPS resistance in monocytic cells through interference with key signal-transduction pathways.     

Relations between the effect of tetanus toxin on the neuromuscular transmission and histological functional properties of various muscles of the rat

Summary Various doses of tetanus toxin were injected into three hind leg and two fore leg muscles of the rat. The neuromuscular transmission was tested by recording the mass action potential of the muscles elicited by a single electrical stimulus to the motor nerve after strong symptoms of local tetanus had developed. The muscle responses were depressed and blocked at lower toxin doses in the fast tibialis anterior than in the mixed gastrocnemius latemlis, while blocking of the slow soleus required the highest dose. The extensor carpi radialis and the flexor carpi ulnaris muscles showed medium sensitivity. In all five muscles the contraction time was measured and correlated with its individual minimal blocking dose. The more phasic (i.e., the faster) the muscle, the more sensitive its neuromuscular transmission was to tetanus toxin. The proportional distribution of red, white, and intermediate fibres, which are associated with specific end-plate types, was evaluated for the five muscles. The percentage of white fibres in the muscles displayed a very good negative correlation with the blocking dose. The relation between structures of end-plates and effects of tetanus toxin were analysed and it is suggested that the differences in sensitivity to tetanus toxin in the neuromuscular transmission in the five muscles is determined by a differential distribution of endplates with varying sensitivities to this toxin due to structural properties.This study is a part of a doctoral dissertation submitted by one of the authors (H.K.) to the Faculty of Medicine, University of Göttingen. Some of the results were presented at the 48th and 49th Congr. of German Physiol. Soc. (Kretzschmar et al., 1977, 1978) and at the 5th Internat. Conf. on Tetanus (Kretzschmar et al., 1979)