Evidence for an association between a G-protein beta3-gene variant with depression and response to antidepressant treatment.

Abnormal signal transduction pathways have been implicated in the pathogenesis of bipolar disorder and major depression. G-proteins are key elements of these pathways in the regulation of cellular responses by transmission of signals from receptors to effector proteins. In recent years several studies have reported altered levels and activities of G-protein alpha subunits in depressive patients. A recently identified polymorphism of a G-protein beta3 subunit (C825T) has been shown to be associated with increased signal transduction and ion transport activity. Therefore, we investigated whether this Gbeta3 polymorphism is associated with affective disorders or with the response to antidepressant treatment in 88 depressive patients (10 bipolar disorder, 78 major depression) compared with 68 schizophrenic patients and 111 healthy controls. We found a significantly higher frequency of the T allele in depressive patients than in healthy controls (genotype: chi2 = 9.571, df = 2, p = 0.008; alleles: p = 0.004, OR = 1.87, 95% CI 1.23-2.84; Fisher's exact test, two sided) and schizophrenic patients (genotype: chi2 = 8.037, df = 2, p = 0.018; alleles: p = 0.009, OR = 1.94, 95% CI 1.99-3.14; Fisher's exact test, two sided). We also found a statistical significant association between TT homozygosity and response to antidepressant treatment after four weeks (p = 0.01). The results of this study suggest that the investigated G-protein beta3 subunit seems to be a susceptibility factor for major depression and maybe even for bipolar disorder, but not for schizophrenia. Further, the presence of the T allele could be an indicator for treatment response.

The role of calcium in Chlamydomonas photomovement responses as analysed by calcium channel inhibitors.

Phototaxis and light-induced stop responses in Chlamydomonas are known to be calcium dependent. We show that phototaxis is stereoselectively inhibited by dihyropyridines, verapamil, diltiazem, omega-conotoxin and pimozide, all inhibitors of slow L-type calcium channels. In contrast, the stop response in Chlamydomonas can be specifically reduced only by omega-conotoxin and pimozide. The light-regulated calcium uptake as detected by 45calcium can be completely suppressed by verapamil and omega-conotoxin but not by diltiazem or any of the dihyropyridine-type calcium channel inhibitors. We conclude that phototaxis and stop response in Chlamydomonas are regulated by three distinguishable drug receptor sites. One of them controls phototaxis and is sensitive to verapamil. The second site controls stop response and phototaxis and shows a high sensitivity to omega-conotoxin and pimozide. These two drug receptors seem to be localized in the plasma membrane and function as ion channels. In addition, calcium influences internal signal transduction from the photoreceptor to the flagella. This internal role of calcium is inhibited by the dihydropyridine binding to a dihydropyridine receptor protein. The arylazide-1,4-dihydropyridine[3H]azidopine binds with a Kd = 35 nM to a 50 kDa protein located in one of the internal cell membranes. Azidopine binding is fully reversible and can be partially inhibited by nimodipine and PN-200110. This protein is the first identified dihyropyridine receptor in an unicellular plant cell. It might serve as an internal calcium regulating channel in Chlamydomonas.

[Intrafocal wiring of fractures of the wrist joint]. / Intrafokale Verdrahtung bei Handgelenkfrakturen.

This method discussed by Kapandji (1976) in which pins are passed through the fracture line and not through the styloid process provides dynamic pinning in comminuted fractures in the adult resulting from compression and extension. No plaster is used. The authors report the experience of the unit of hand surgery in the Centre de Traumatologie et d'Orthopédie of Strasbourg (150 cases at present). They describe the technique and the indications.