[Application of damage control concept in severe limbs fractures combining with multiple trauma].

OBJECTIVE: To discuss the application and clinical effect of damage control concept in the treatment of severe limbs fractures combining with multiple trauma. METHODS: From July 2009 to July 2012, 30 patients with severe limbs fractures combining with multiple trauma were treated with the damage control concept, included 20 males and 10 females with an average age of (34.03 ± 12.81) years old ranging from 20 to 60 years old; the ISS averaged (35.00 ± 12.81) points (ranged from 26 to 54 points). And the control group also contained 30 patients with severe limbs fractures combining with multiple trauma treated by the traditional operation from June 2006 to June 2009, there were 23 males and 7 females with an average age of (34.23 ± 11.04) years old ranging from 18 to 65 years old. The ISS averaged (35.56 ± 11.04) points (ranged from 26 to 51 points). The age, gender, ISS, Gustilo classification, operation time, intraoperative blood loss, blood transfusion,postoperative complications and mortality rate were observed and compared. RESULTS: In the damage control concept group,there were 28 cases surviving and 2 cases (6.7%) death; 6 cases of postoperative complication included 2 cases of adult respiratory distress syndrome, 1 case of multiple organ failure, 1 case of disseminated intravascular coagulation and 2 cases of wound infection. In the control group, there were 22 cases surviving and 8 cases death(26.7%); 13 cases of postoperative complication included 4 cases of adult respiratory distress syndrome,2 cases of multiple organ failure, 2 cases of disseminated intravascular coagulation and 3 cases of wound infection. There were no statistically significant differences between two groups in age, gender, ISS, Gustilo classfication and complication (P > 0.05), however there were statistically significant differences in mortality rate, operation time, blodd loss, blodd transfusion between two groups (P < 0.05). CONCLUSION: Damage control concept is used to treat severe limbs fractures combining with multiple trauma which has the rapid and effective therapy, can improve survival rate and reduce complication.

Ring finger protein 34 (RNF34) interacts with and promotes γ-aminobutyric acid type-A receptor degradation via ubiquitination of the γ2 subunit.

We have found that the large intracellular loop of the γ2 GABAA receptor (R) subunit (γ2IL) interacts with RNF34 (an E3 ubiquitin ligase), as shown by yeast two-hybrid and in vitro pulldown assays. In brain extracts, RNF34 co-immunoprecipitates with assembled GABAARs. In co-transfected HEK293 cells, RNF34 reduces the expression of the γ2 GABAAR subunit by increasing the ratio of ubiquitinated/nonubiquitinated γ2. Mutating several lysines of the γ2IL into arginines makes the γ2 subunit resistant to RNF34-induced degradation. RNF34 also reduces the expression of the γ2 subunit when α1 and ß3 subunits are co-assembled with γ2. This effect is partially reversed by leupeptin or MG132, indicating that both the lysosomal and proteasomal degradation pathways are involved. Immunofluorescence of cultured hippocampal neurons shows that RNF34 forms clusters and that a subset of these clusters is associated with GABAergic synapses. This association is also observed in the intact rat brain by electron microscopy immunocytochemistry. RNF34 is not expressed until the 2nd postnatal week of rat brain development, being highly expressed in some interneurons. Overexpression of RNF34 in hippocampal neurons decreases the density of γ2 GABAAR clusters and the number of GABAergic contacts that these neurons receive. Knocking down endogenous RNF34 with shRNA leads to increased γ2 GABAAR cluster density and GABAergic innervation. The results indicate that RNF34 regulates postsynaptic γ2-GABAAR clustering and GABAergic synaptic innervation by interacting with and ubiquitinating the γ2-GABAAR subunit promoting GABAAR degradation.

Molecular and functional interaction between protocadherin-γC5 and GABAA receptors.

We have found that the γ2 subunit of the GABA(A) receptor (γ2-GABA(A)R) specifically interacts with protocadherin-γC5 (Pcdh-γC5) in the rat brain. The interaction occurs between the large intracellular loop of the γ2-GABA(A)R and the cytoplasmic domain of Pcdh-γC5. In brain extracts, Pcdh-γC5 coimmunoprecipitates with GABA(A)Rs. In cotransfected HEK293 cells, Pcdh-γC5 promotes the transfer of γ2-GABA(A)R to the cell surface. We have previously shown that, in cultured hippocampal neurons, endogenous Pcdh-γC5 forms clusters, some of which associate with GABAergic synapses. Overexpression of Pcdh-γC5 in hippocampal neurons increases the density of γ2-GABA(A)R clusters but has no significant effect on the number of GABAergic contacts that these neurons receive, indicating that Pcdh-γC5 is not synaptogenic. Deletion of the cytoplasmic domain of Pcdh-γC5 enhanced its surface expression but decreased the association with both γ2-GABA(A)R clusters and presynaptic GABAergic contacts. Cultured hippocampal neurons from the Pcdh-γ triple C-type isoform knock-out (TCKO) mouse (Pcdhg(tcko/tcko)) showed plenty of GABAergic synaptic contacts, although their density was reduced compared with sister cultures from wild-type and heterozygous mice. Knocking down Pcdh-γC5 expression with shRNA decreased γ2-GABA(A)R cluster density and GABAergic innervation. The results indicate that, although Pcdh-γC5 is not essential for GABAergic synapse formation or GABA(A)R clustering, (1) Pcdh-γC5 regulates the surface expression of GABA(A)Rs via cis-cytoplasmic interaction with γ2-GABA(A)R, and (2) Pcdh-γC5 plays a role in the stabilization and maintenance of some GABAergic synapses.

Differential regulation of the postsynaptic clustering of γ-aminobutyric acid type A (GABAA) receptors by collybistin isoforms.

Collybistin promotes submembrane clustering of gephyrin and is essential for the postsynaptic localization of gephyrin and γ-aminobutyric acid type A (GABA(A)) receptors at GABAergic synapses in hippocampus and amygdala. Four collybistin isoforms are expressed in brain neurons; CB2 and CB3 differ in the C terminus and occur with and without the Src homology 3 (SH3) domain. We have found that in transfected hippocampal neurons, all collybistin isoforms (CB2(SH3+), CB2(SH3-), CB3(SH3+), and CB3(SH3-)) target to and concentrate at GABAergic postsynapses. Moreover, in non-transfected neurons, collybistin concentrates at GABAergic synapses. Hippocampal neurons co-transfected with CB2(SH3-) and gephyrin developed very large postsynaptic gephyrin and GABA(A) receptor clusters (superclusters). This effect was accompanied by a significant increase in the amplitude of miniature inhibitory postsynaptic currents. Co-transfection with CB2(SH3+) and gephyrin induced the formation of many (supernumerary) non-synaptic clusters. Transfection with gephyrin alone did not affect cluster number or size, but gephyrin potentiated the clustering effect of CB2(SH3-) or CB2(SH3+). Co-transfection with CB2(SH3-) or CB2(SH3+) and gephyrin did not affect the density of presynaptic GABAergic terminals contacting the transfected cells, indicating that collybistin is not synaptogenic. Nevertheless, the synaptic superclusters induced by CB2(SH3-) and gephyrin were accompanied by enlarged presynaptic GABAergic terminals. The enhanced clustering of gephyrin and GABA(A) receptors induced by collybistin isoforms was not accompanied by enhanced clustering of neuroligin 2. Moreover, during the development of GABAergic synapses, the clustering of gephyrin and GABA(A) receptors preceded the clustering of neuroligin 2. We propose a model in which the SH3- isoforms play a major role in the postsynaptic accumulation of GABA(A) receptors and in GABAergic synaptic strength.

Involvement of taurine in penicillin-induced epilepsy and anti-convulsion of acupuncture: a preliminary report.

The potential role of taurine on epilepsy and acupuncture anti-convulsion was addressed in the present study. Epilepsy was induced by micro-injection of penicillin into hippocampus of Wistar rats. Taurine was applied by intraperitioneal (i.p.) injection. Electro-acupuncture (EA) was performed on acupoints of DU 20 "Bai Hui" and DU 16 "Feng Fu" along DU channel. Epileptic grades were evaluated by electro-encephalography (EEG) and behavior score. We featured the dose-response relationship between taurine-treated epilepsy and epilepsy-only subjects, detected the effect of exogenous taurine on epilepsy and acupuncture treatment, and investigated taurine transporter immuno-activity in hippocampus using immunohistochemistry. It was found that: 1), taurine had a significant antiepileptic effect as applied at i.p. 20 mg/kg, 40mg/kg, 80mg/kg, especially at 40mg/kg in the rat model of penicillin-induced seizure. Animals were improved by one to three Racine grades in behavior and in frequency and amplitude of EEG. 2), Exogenous taurine enhanced the anti-convulsive effect of EA. Both behavior and EEG were improved in taurine-treated rats. EA inhibited epilepsy. Exogenous taurine improved epilepsy in a synergistic manner to EA. 3), EA increased the concentration of taurine transporter in hippocampus by comparing EA-treated epilepsy with normal control and penicillin only, or EA-treated plus taurine-treated epilepsy with taurine-treated only epilepsy and penicillin only. The resulting data suggested that taurine may play an inhibitory role against epilepsy as an inhibitory amino acid in the central nervous system and EA may inhibit epilepsy via upregulating the concentration of taurine transporter to increase the release of taurine.

Electro-acupuncture improves epileptic seizures induced by kainic acid in taurine-depletion rats.

Electro-acupuncture (EA) partially inhibited epilepsy with great success. The biological basis underlying EA anti-convulsion remained uncertain, which resulted in limited application and slow improvement of acupuncture. Our previous study indicated that taurine may play an inhibitory role against epilepsy as an inhibitory amino acid in the central nervous system and EA may inhibit epilepsy via up-regulating the expression of taurine transporter to increase the release of taurine. Involvement of taurine in kainic acid (KA)-induced epilepsy and anti-convulsion of EA was further addressed on taurine deficiency animal in the present work. We instituted endogenous taurine-deficiency model by supplementation of beta-alanine (3%) in drinking water for continuous 10 days initially, injected KA into lateral cerebral ventricle to induce epileptic seizure, and performed EA treatment on DU26 "RenZhong" and K "YongQuan" acupoints by an EA apparatus (Model G6805-2) using successive waves with the frequency 64Hz and the current intensity 0.8-1.0 mA for 30 minutes in Sprague-Dawley (SD) rats. Taurine levels markedly decreased in cortex, hippocampus, striatum and cerebellum of rats after beta-alanine administration by fluore-HPLC measurement. EA alleviated epileptic activity in rats at 3.5 h time point after KA injection, whereas beta-alanine-induced taurine depletion rendered rats more susceptible to KA-induced epilepsy. Taurine transporter level increased after EA treatment. These results suggested that taurine participated in epileptogenesis and EA may be related to taurine in controlling epileptic seizure.