Connexin:a potential novel target for protecting the central nervous system?

Connexin subunits are proteins that form gap junction channels, and play an important role in communication between adjacent cells. This review article discusses the function of connexins/hemichannels/gap junctions under physiological conditions, and summarizes the findings re-garding the role of connexins/hemichannels/gap junctions in the physiological and pathological mechanisms underlying central nervous system diseases such as brain ischemia, traumatic brain and spinal cord injury, epilepsy, brain and spinal cord tumor, migraine, neuroautoimmune disease, Alzheimer’s disease, Parkinson’s disease, X-linked Charcot-Marie-Tooth disease, Peli-zaeus-Merzbacher-like disease, spastic paraplegia and maxillofacial dysplasia. Connexins are considered to be a potential novel target for protecting the central nervous system.

Cortical spreading depression-induced preconditioning in the brain

Cortical spreading depression is a technique used to depolarize neurons. During focal or global ischemia, cortical spreading depression-induced preconditioning can enhance tolerance of further injury. However, the underlying mechanism for this phenomenon remains relatively unclear. To date, numerous issues exist regarding the experimental model used to precondition the brain with cortical spreading depression, such as the administration route, concentration of potassium chloride, induction time, duration of the protection provided by the treatment, the regional distribution of the protective effect, and the types of neurons responsible for the greater tolerance. In this review, we focus on the mechanisms underlying cor- tical spreading depression-induced tolerance in the brain, considering excitatory neurotransmission and metabolism, nitric oxide, genomic reprogramming, inflammation, neurotropic factors, and cellular stress response. Specifically, we clarify the procedures and detailed information regarding cortical spreading depression-induced preconditioning and build a foundation for more comprehensive investigations in the field of neural regeneration and clinical application in the future.

Gerstmann-Str?ussler-Scheinker disease: A case report

BACKGROUND Gerstmann-Str?ussler-Scheinker(GSS) disease is an inherited prion disease that is clinically characterized by the early onset of progressive cerebellar ataxia. The incidence of GSS is extremely low and it is particularly rare in China. Therefore,clinicians may easily confuse this disease with other diseases that also cause ataxia, resulting in its under-diagnosis or misdiagnosis.CASE SUMMARY Here, we report the first case of genetically diagnosed GSS disease in Northeast China. The patient exhibited typical ataxia and dysarthria 2.5 years after symptom onset. However, magnetic resonance imaging of the brain and spinal cord revealed a normal anatomy. Screening results for the spinocerebellar ataxia gene were also negative. We thus proposed to expand the scope of genetic screening to include over 200 mutations that can cause ataxia. A final diagnosis of GSS was presented and the patient was followed for more than 3.5 years, during which we noted imaging abnormalities. The patient gradually exhibited decorticate posturing and convulsions. We recommended administration of oral sodium valproate, which resolved the convulsions.CONCLUSION Patients with inherited ataxia should be considered for a diagnosis of GSS via genetic testing at an early disease stage.

Significantly Enhanced Melt Memory Effect of Metallocene-made Isotactic Polypropylene Containing Talc

The melt memory effect is a widely observed phenomenon in semi-crystalline polymers. In practical applications, various additives are usually introduced into polymers, which may affect their melt memory behavior. In this work, the effect of talc on the melt memory effect of metallocene-made isotactic polypropylene(M-PP) was investigated in detail by using the differential scanning calorimetry. The results indicated that the introduction of talc significantly strengthened the melt memory effect of M-PP. Specifically, the upper limit temperature of Domain II increased from 161 ℃ to 174 ℃, resulting in a substantial widening of the temperature range of Domain IIa from 1 ℃ to 14 ℃. Analysis of the crystal orientation of the M-PP containing talc cooled from various Ts suggested that the remarkably enhanced melt memory effect could be ascribed to the stabilization of oriented nuclei facilitated by talc. This stabilizing effect was likely attributable to the prefreezing effect or the sorption interaction between talc and the M-PP chains.

Fabry disease with acute cerebral infarction onset in a young patient

To the Editor:Fabry disease (FD)is a recessive X-linked hereditary disease.The onset age of the disease is in children and adolescents mostly.The average time from the onset of symptoms to the definite diagnosis needs 13.7 years in male patients and 16.3 years in female patients.FD happens rarely and it is easy to cause diagnosis and treatment delay.Here,we report a case of FD in a 27-year-old man who developed clinical symptoms with acute cerebral infarction onset to improve doctors' understanding of FD.

Comparative Investigation on Step-cycle Tensile Behaviors of Two Bimodal Pipe-grade Polyethylene with Different Slow Crack Growth Resistance

In this work,step-cycle tensile behavior of two bimodal polyethylene(PE)materials,a PEI 00 grade pipe material,XS10,and a PEI 00-RC(Resistant Crack)grade pipe material,XSC50,was comparatively investigated.By decomposing the strain into a recoverable part and an unrecoverable part,it was found that the deformation recovery capability of XSC50 during stretching was larger than that of XS10.Structural evolution characterized by in situ synchrotron small angle X-ray scattering indicated that the fragmentation of initial crystals in XSC50 occurred at lower strain than in XS10.Considering that XSC50 had relatively small lamellar thickness and similar crystallinity to XS10,we speculated that the larger deformation recovery capability of XSC50 during stretching probably derived from stronger entangled amorphous region caused by larger density of tie molecules and entanglements,which were usually regarded to have a significant influence on the slow crack growth(SCG)resistance of PE materials.As expected,the experimental result of strain hardening modulus test suggested that the deformation recovery capability during stretching was positively correlated with the SCG resistance for XS10 and XSC50 used in this work.The step-cycle tensile test had the potential to be developed into a supplement for comparison of SCG resistance of PE materials.

Reversible Plasticity Shape Memory Effect in SEBS/Crystallizable Paraffin: Influence of Paraffin Content

Polymers with reversible plasticity shape memory effect(RPSME)have attracted considerable attention due to their simple programming and large deformation.However,the exact mechanisms of RPSME are still not thoroughly understood.In this work,the RPSME of SEBS/crystallizable paraffin was investigated by comparatively analyzing the performances and microstructures of samples with different paraffin content.It was found the shape fixing ratios(Rfs)of samples increased with the paraffin content,and interestingly,a significant improvement in Rf was observed when the paraffin content exceeded 60 wt%.Tensile test results showed that the deformation characteristics of samples changed from elastic to plastic as the paraffin content increased above 60 wt%.By exploring the crystallization behaviors of paraffin in various SEBS/paraffin samples,it was revealed that the microstructures of SEBS/paraffin were different when the paraffin content was below 50 wt%and above 60 wt%.In samples with low paraffin content(below 50 wt%),nearly all paraffin was co-crystallized with ethylene-co-butylene(EB)chains and its crystallization was severely restricted;while in samples with high paraffin content(above 60 wt%),“excess”paraffin appeared and this part of paraffin crystallized on the template of the EB/paraffin co-crystals,which might be responsible for the elastic-to-plastic transition and the sharp increase in Rf.Based on the above results,a possible structural model was proposed to explain the exact mechanism of RPSME in SEBS/paraffin.