Preliminary studies on the interaction of TNF alpha and IFN gamma with alpha 2-macroglobulin.

The binding of 125I-labelled recombinant human TNF alpha and IFN gamma to isolated human blood alpha 2-macroglobulin has been investigated using molecular sieving procedures and non-denaturing PA gel electrophoresis in combination with autoradiography. These studies revealed that both cytokines readily bind to the electrophoretically fast form of alpha 2M generated by methylamine or protease treatment of this protein. PAGE/SDS gel investigations indicated that TNF alpha bound non-covalently while the IFN gamma interaction was covalent in nature. Preliminary competition studies also indicate that cold TNF alpha and IL-2 are more effective than cold IFN gamma at inhibiting the binding of labelled IFN gamma to alpha 2M. Bioassays revealed that "native" alpha 2M or its derivatives at 2 mg/ml concentration did not impair the antiproliferative effects of TNF alpha and IFN gamma on susceptible bladder tumour cell lines. Furthermore they did not interfere in the induction of Class II antigen expression by IFN gamma on inducible cell lines or in a 2-site ELISA assay for TNF.     

A Common Variant in ERBB4 Regulates GABA Concentrations in Human Cerebrospinal Fluid

The neuregulin 1 (NRG1) receptor ErbB4 is involved in the development of cortical inhibitory GABAergic circuits and NRG1-ErbB4 signaling has been implicated in schizophrenia (SCZ). A magnetic resonance spectroscopy (¹H-MRS) study has demonstrated that a single-nucleotide polymorphism in ERBB4, rs7598440, influences human cortical GABA concentrations. Other work has highlighted the significant impact of this genetic variant on expression of ERBB4 in the hippocampus and dorsolateral prefrontal cortex in human post mortem tissue. Our aim was to examine the association of rs7598440 with cerebrospinal fluid (CSF) GABA levels in healthy volunteers (n=155). We detected a significant dose-dependent association of the rs7598440 genotype with CSF GABA levels (G-allele standardized β=−0.23; 95% CIs: −0.39 to −0.07; P=0.0066). GABA concentrations were highest in A homozygous, intermediate in heterozygous, and lowest in G homozygous subjects. When excluding subjects on psychotropic medication (three subjects using antidepressants), the results did not change (G-allele standardized β=−0.23; 95% CIs: −0.40 to −0.07; P=0.0051). The explained variance in CSF GABA by rs7598440 in our model is 5.2% (P=0.004). The directionality of our findings agrees with the aforementioned ¹H-MRS and gene expression studies. Our observation therefore strengthens the evidence that the A-allele of rs7598440 in ERBB4 is associated with increased GABA concentrations in the human central nervous system (CNS). To our knowledge, our finding constitutes the first confirmation that CSF can be used to study genotype–phenotype correlations of GABA levels in the CNS. Such quantitative genetic analyses may be extrapolated to other CSF constituents relevant to SCZ in future studies.     

Comparison of different routes of administration of nadroparin in hemodialysis

AIM: In an open, crossover, randomized study in hemodialysis patients, we investigated possible differences of the effect of the low molecular weight heparin (LMWH) nadroparin/fraxiparine in relation to the route of administration. PATIENTS AND METHODS: The effect of nadroparin, administered by the venous line or by the arterial line after priming of the extracorporeal circuit with a part of the total dose administered, was compared with administration of the same dose by the arterial line as recommended by the manufacturer. Twelve stable, chronic hemodialysis patients were studied during 3 dialysis sessions for each treatment option. Concomitant medication was kept constant. RESULTS: Results obtained after administration of nadroparin by the venous line were comparable to those obtained after administration by the arterial line. When a part of the dose was added to the priming solution, the anti-Xa activity, measured after 2 hours of dialysis, was somewhat lower (p = 0.09). There was also a tendency towards longer manual compression time in this group. There was no difference in hemoglobin, serum urea and creatinine before the study and at the end of each treatment option. CONCLUSION: We therefore conclude that the safety and efficacy of administration of LMWH by the arterial and by the venous route are identical. There is no need for addition of a small dose of LMWH to the priming fluid.     

Prevention of B cell antigen receptor-induced apoptosis by ligation of CD40 occurs downstream of cell cycle regulation

Cross-linking of the B cell antigen receptor (BCR) on germinal center B cells can induce growth arrest and apoptosis, thereby eliminating potentially autoreactive B cells. Using the Burkitt lymphoma cell line Ramos as a model, we studied the commitment to apoptosis following growth arrest, as well as how triggering of CD40 or addition of tumor necrosis factor (TNF)-alpha can interfere to block cell death. Both BCR triggering and direct induction of growth arrest by sodium butyrate (n-But) caused hypophosphorylation of the retinoblastoma protein (pRb), followed by apoptosis. Interestingly, although CD40 ligation or TNF-alpha efficiently prevented BCR-induced and n-But-induced apoptosis, these co-stimuli did not inhibit, but rather augmented, growth arrest. Analysis of cell cycle regulators showed that each apoptotic and T(h) stimulus distinctly affected cyclins or cyclin-dependent kinase inhibitors, indicating that growth arrest can be uncoupled from apoptosis. BCR ligation and growth arrest activated the intrinsic or mitochondrial route of apoptosis. CD40 ligation and TNF-alpha prevented release of cytochrome c and activation of caspase-3, which could not be explained by effects on the expression of Bcl-2, Bcl-x(L) or Bax. Finally, the onset of BCR-induced apoptosis occurred after 10-12 h and addition of CD40 mAb or TNF-alpha at that point still prevented further execution of apoptosis. We conclude that in mature B cells apoptosis is not an obligatory event following growth arrest. Instead, commitment to apoptosis can be rapidly controlled by T cells via CD40 ligand and TNF-alpha, downstream of the pRb-regulated restriction point of the cell cycle, but prior to mitochondrial cytochrome c release.     

Effect of alcohol intake and cigarette smoking on sperm parameters and pregnancy

Much has been published about smoking and alcohol intake influencing male fertility, sperm parameters and reproductive outcome. However, there is no conclusive agreement about the effects of cigarette smoking and alcohol use on these outcomes and thus no generally accepted guidelines. The combined effect of cigarette smoking and alcohol intake, though, has not been rigorously investigated. Because alcohol consumption and smoking are often seen together, this study focuses on the effect of smoking and drinking habits separately and combined on semen parameters, such as volume, sperm count, motility and morphology, and on pregnancy outcome. These suggested toxic effects are studied in a group of subfertile, asthenozoospermic men (<10% motile spermatozoa), compared with a group of ‘proven fertile’, healthy men. The extreme asthenozoospermic group has especially been chosen because of the suspected effect, that is, oxidative stress, on sperm motility. In our study, we found that cigarette smoking and alcohol intake did not differ between the subfertile and fertile group. In conclusion, cigarette smoking and alcohol consumption do not appear to significantly affect sperm parameters, such as volume, sperm count, motility and morphology or pregnancy outcome in our study population.     

Aufklappende Osteotomie des Tibiakopfes

Background

Lesions of the popliteal artery during high tibial osteotomy are rare complications, consequently the majority of publications are case related. The interval between surgery and diagnosis is reported to be as long 3 years; therefore, the current literature probably does not reflect the true incidence of vascular injuries.

Objective

The case reports published in the literature were further evaluated. The focus was on the normal vascular anatomy of the popliteal region and anatomical deviations that predispose to vascular injury. As the flexion angle of the knee joint is considered to be decisive for vascular injury, this aspect was also an additional focus. For the unlikely event of a vascular injury, recommendations are presented which indicate diagnostic and therapeutic decisions.

Methods

We analyzed the available literature and present own magnetic resonance imaging (MRI) investigations of the popliteal artery with different angles of flexion in six healthy volunteers.

Results and discussion

A variation of the origin of the anterior tibial artery with a course between the posterior tibial cortex and the popliteal muscle was found in 6?% of all patients and predisposes to an accidental injury during osteotomy. The results in the literature and our own MRI findings suggest that a flexion angle of 90° facilitates anatomical dissection and osteotomy but cannot be regarded as a reliable protection against vascular injury.