Integrin CD11b Deficiency Aggravates Retinal Microglial Activation and RGCs Degeneration After Acute Optic Nerve Injury.

Neuroinflammation plays a vital role in the process of a variety of retinal ganglion cells (RGCs) degenerative diseases including traumatic optic neuropathy (TON). Retinal microglial activation is believed as a harbinger of TON, and robust microglial activation can aggravate trauma-induced RGCs degeneration, which ultimately leads to RGCs loss. Toll like receptor 4 (TLR4)-triggered inflammation is of great importance in retinal inflammatory response after optic nerve injury. CD11b on macrophage and brain microglia can inhibit TLR4-triggered inflammation. However, the functional role of CD11b in retinal microglia is not well understood. Here, using an optic nerve crush model and CD11b gene deficient mice, we found that CD11b protein expression was mainly on retinal microglia, significantly increased after optic nerve injury, and still maintained at a high level till at least 28 days post crush. Compared with wild type mice, following acute optic nerve injury, CD11b deficient retinae exhibited more exacerbated microglial activation, accelerated RGCs degeneration, less growth associated protein-43 expression, as well as more proinflammatory cytokines such as interleukin-6 and tumor necrosis factor α while less anti-inflammatory factors such as arginase-1 and interleukin-10 production. We conclude that CD11b is essential in regulating retinal microglial activation and neuroinflammatory responses after acute optic nerve injury, which is critical for subsequent RGCs degeneration and loss.

Amino-Nogo inhibits optic nerve regeneration and functional recovery via the integrin αv signaling pathway in rats.

BACKGROUND: Nogo-A, a major myelin-associated inhibitor, can inhibit injured optic nerve regeneration. However, whether Amino-Nogo is the most important functional domain of Nogo-A remains unknown. This study aimed to identify the role of Amino-Nogo following optic nerve injury, and the mechanism of the Amino-Nogo-integrin αv signaling pathway in vivo. METHODS: Sprague-Dawley rats with optic nerve crush injury were injected with Nogo-A siRNA (Nogo-A-siRNA), the Nogo-66 functional domain antagonist peptide of Nogo-A (Nep1-40) or a recombinant rat Amino-Nogo-A protein (∆20) into the vitreous cavity to knock down Nogo-A, inhibit Nogo-66 or activate the Amino-Nogo, resparately. Retinal ganglion cell (RGC) density, axon regeneration and the pattern of NPN of visual electrophysiology (flash visual evoked potentials [F-VEP]) at different times post-injury were investigated. RESULTS: Our study revealed a lower RGC survival rate; shorter axonal outgrowth; longer N1, P1 and N2 waves latencies; and lower N1-P1 and P1-N2 amplitudes in the Δ20 group, and Δ20 treatment significantly attenuated integrin αv expression and phosphorylated focal adhesion kinase (p-FAK) levels. In the Nep1-40 and Nogo-A siRNA groups, there were higher RGC survival rates, longer axonal outgrowth, shorter N1 and P1 wave latencies, and higher N1-P1 and P1-N2amplitudes. Nogo-A siRNA treatment significantly increased integrin αv expression and p-FAK levels. Nepl-40 treatment did not alter integrin αv expression. In addition, there was no significant change in integrin α5 in any group. CONCLUSION: These results suggest that the integrin signaling pathway is regulated by Amino-Nogo, which inhibits optic nerve regeneration and functional recovery, and that the integrin subunit involved might be integrin αv but not integrin α5.

Isolated ipsilateral ptosis associated with ventral midbrain infarction: a case report and literature review.

Documented cases of ipsilateral ptosis caused by midbrain infarction remain rare. Herein, we present a patient with isolated ipsilateral ptosis that was initially considered to be a consequence of myasthenia gravis but was subsequently attributed to ventral midbrain infarction. We also discuss the possible underlying mechanisms; ipsilateral ptosis in our patient was attributed to selective damage of the levator palpebral muscle branch of the oculomotor nerve. The patient was started on aspirin (200 mg once daily) and atorvastatin (40 mg once daily). Improvement in ptosis occurred from day 5 of admission, and the patient was subsequently discharged. Ptosis disappeared 1 month after onset. This report describes an extremely rare case of ventral midbrain infarction presenting with isolated ipsilateral ptosis. Careful examination, including magnetic resonance imaging, is essential in such patients, especially in those with multiple cerebrovascular risk factors.

Efficacy of linaclotide in combination with polyethylene glycol for bowel preparation in Chinese patients undergoing colonoscopy polypectomy: protocol for a randomised controlled trial.

BACKGROUND: Adequate bowel preparation is essential for successful colonoscopy and polypectomy procedures. However, a significant proportion of patients still exhibit suboptimal bowel preparation, ranging from 18% to 35%. The effectiveness of bowel preparation agents can be hampered by volume and taste, adversely affecting patient compliance and tolerance. Therefore, exploring strategies to minimise laxative volume and improve patient tolerance and adherence is imperative to ensure optimal bowel preparation quality. METHODS AND ANALYSIS: This study is a two-arm, single-blinded, parallel-group randomised controlled trial designed to compare the efficacy of 2 L polyethylene glycol (PEG) combined with linaclotide with 4 L PEG in bowel cleansing. A total of 422 participants will be randomly assigned in a 1:1 ratio to either the intervention group (2 L PEG combined with 580 µg linaclotide) or the control group (4 L PEG). The primary outcome measure is bowel cleansing efficacy, which is assessed using the Boston Bowel Preparation Scale. Secondary outcomes include evaluating the tolerability and safety of the bowel preparation regimens, bowel diary assessments, postpolypectomy complications (such as bleeding and perforation) and the size and number of removed polyps. ETHICS AND DISSEMINATION: The study has received approval from the Clinical Research Ethics Committee of The First Affiliated Hospital, Zhejiang University School of Medicine. The findings of this trial will serve as a valuable resource for clinicians and patients undergoing colonoscopy polypectomy by guiding the selection of appropriate bowel preparation regimens. Study findings will be disseminated to participants, presented at professional society meetings, and published in peer-reviewed journals. This trial was registered on the Chinese Clinical Trial Registry with registration number ChiCTR2300075410.

Inhibition of retinal ganglion cell axonal outgrowth through the Amino-Nogo-A signaling pathway.

Nogo-A is a myelin-derived inhibitor playing a pivotal role in the prevention of axonal regeneration. A functional domain of Nogo-A, Amino-Nogo, exerts an inhibitory effect on axonal regeneration, although the mechanism is unclear. The present study investigated the role of the Amino-Nogo-integrin signaling pathway in primary retinal ganglion cells (RGCs) with respect to axonal outgrowth, which is required for axonal regeneration. Immunohistochemistry showed that integrin αv, integrin α5 and FAK were widely expressed in the visual system. Thy-1 and GAP-43 immunofluorescence showed that axonal outgrowth of RGCs was promoted by Nogo-A siRNA and a peptide antagonist of the Nogo-66 functional domain of Nogo-A (Nep1-40), and inhibited by a recombinant rat Nogo-A-Fc chimeric protein (Δ20). Western blotting revealed increased integrin αv and p-FAK expression in Nogo-A siRNA group, decreased integrin αv expression in Δ20 group and decreased p-FAK expression in Nep1-40 group. Integrin α5 expression was not changed in any group. RhoA G-LISA showed that RhoA activation was inhibited by Nogo-A siRNA and Δ20, but increased by Nep1-40 treatment. These results suggest that Amino-Nogo inhibits RGC axonal outgrowth primarily through the integrin αv signaling pathway.

Intracranial large artery embolism due to carotid thrombosis caused by a neck massager: A case report.

BACKGROUND: There are few reported cases of intracranial large artery embolism due to carotid thrombosis caused by a neck massager. Herein we report such a case. CASE SUMMARY: A 49-year-old woman presented with left limb weakness and dysarthria after a history of neck massage for 1 mo. Neurological examination showed left central facial paralysis and left hemiparesis with a National Institutes of Health Stroke Scale score of 12. Brain magnetic resonance imaging revealed restricted diffusion on diffusion-weighted imaging in the right parietal and temporal lobes. Computed tomography angiography (CTA) indicated M3 segment embolism of the right middle cerebral artery. Neck CTA revealed thrombosis of the bilateral common carotid arteries. Carotid ultrasound showed thrombosis in the bilateral common carotid arteries (approximately 2 cm below the proximal end of the carotid sinus), and contrast-enhanced ultrasound did not suggest enhancement. No hypertension, diabetes, heart disease, vasculitis, or thrombophilia was found after admission. After 1 wk of treatment with aspirin 200 mg and atorvastatin 40 mg, a carotid ultrasound reexamination showed that the thrombosis had significantly reduced. CONCLUSION: Neck massager may cause carotid artery thrombosis.

[Involvement of Cdk5/p35 and tau protein in the hippocampal mossy fiber sprouting in the PTZ kindling model].

OBJECTIVE: To observe the expression of cyclin-dependent kinase 5 (Cdk5), p35, tau protein and the activity of Cdk5 in rat hippocampus during pentylenetetrazole (PTZ) kindling process and their correlation with mossy fiber sprouting (MFS) so as to investigate the role of Cdk5/p35 in epileptogenesis. METHODS: A total of 240 healthy male SD rats were divided randomly into normal controls and pentylenetetrazole (PTZ) treatment groups. The epileptic models were established by injection of PTZ intraperitoneally. At Day 3, Weeks 1, 2, 4 & 6 after a daily injection of PTZ, Timm staining was scored in the CA3 region and dentate gyrus. At the same time, the mRNA and protein of Cdk5 and p35, total tau protein and its phosphorylation at ser202 and Cdk5 activity were analyzed in the hilus and stratum granulosum of dentate gyrus and the CA1, CA3 regions of hippocampus. The methods of in situ hybridization, immunohistochemistry, Western blot and immuno-precipitation and liquid scintillation counter were employed respectively. RESULTS: Prominent MFS was observed in area CA3 rather than the inner molecular layer in PTZ-treated rats. And the degree of MFS progressed with the development of behavioral kindled seizures. The expressions of Cdk5/p35 mRNA and protein, tau protein and its phosphorylation at Ser202 significantly increased from Day 3 to Week 4 in the PTZ treatment group. It was in accordance with the progression of MFS in area CA3. CONCLUSION: Cdk5/p35 and its substrate tau protein may be involved in MFS. Understanding the molecular mechanisms of MFS may lead to therapeutic interventions for limiting epileptogenesis.

Potential roles of Cdk5/p35 and tau protein in hippocampal mossy fiber sprouting in the PTZ kindling model.

BACKGROUND: The most well-documented synaptic reorganization associated with temporal lobe epilepsy is mossy fiber sprouting (MFS), which is believed to play a critical role in epileptogenesis. However, the molecular mechanisms underlying this phenomenon remain unclear. Cyclin-dependent kinase 5 (Cdk5) is a proline-directed serine/threonine kinase which is found to be crucial in axon growth and synaptic plasticity. We hypothesized that Cdk5 contributed to MFS via phosphorylating its substrate tau protein, which was known to facilitate microtubule stabilization and axonal elongation. METHODS: 240 male SD rats were randomly divided into the control group and PTZ group. The epileptic models were established by intraperitoneal PTZ injection, while the control rats were injected with an equal dose of saline. At different time points, Cdk5/p35 mRNA and protein, total tau protein and its phosphorylation at Ser202 (p-tau) and Cdk5 activity were analyzed in different regions of hippocampus by in situ hybridization, immunohistochemistry, Western blot, immuno-precipitation and liquid scintillation counter. Hippocampus was also evaluated for MFS with Timm stain. RESULTS: Prominent MFS was observed in area CA3 rather than the inner molecular layer in PTZ treated rats and the degree of MFS progressed with the development of behavioral kindled seizures. The expression of Cdk5/p35 mRNA and protein, tau protein and its phosphorylation at Ser202 significantly increased from 3 days to 4 weeks in the PTZ group, which was in accordance with the progression of MFS in area CA3. CONCLUSIONS: Cdk5/p35 and its substrate tau protein may be involved in MFS. Understanding the molecular mechanisms underlying MFS may lead to therapeutic interventions that limit epileptogenesis.

Mossy fiber sprouting, hippocampal damage and spontaneous recurrent seizures in pentylenetetrazole kindling rat model.

AIM: The aim of this study was to determine the correlations among hippocampal damage, spontaneous recurrent seizures (SRS), and mossy fiber sprouting (MFS) using pentylenetetrazole (PTZ) kindling model. METHODS: Chronic epileptic model was established by administration of PTZ. Behaviour and EEG seizure activity were recorded. Rats' hippocampus were analyzed with haematoxylin and eosin (H&E) stain for histological lesions and evaluated for MFS with Timm stain. RESULTS: Prominent MFS was observed in area CA3 rather than the inner molecular layer in PTZ treated rats and the degree of MFS progressed with the development of behavioral kindled seizures. MFS preceded the occurrence of spontaneous seizures. No obvious neuronal necrosis and loss were observed in different regions of the hippocampus during kindling progression. CONCLUSION: MFS is not the outcome of SRS. Severe hippocampal damage is not required in the development of MFS and SRS.

Microbial degradation of sulfur, nitrogen and oxygen heterocycles.

Sulfur (S), nitrogen (N) and oxygen (O) heterocycles are among the most potent environmental pollutants. Microbial degradation of these pollutants is attracting more and more attention because such bioprocesses are environmentally friendly. The biotechnological potential of these processes is being investigated, for example, to achieve better sulfur removal by immobilized biocatalysts with magnetite nanoparticles or by solvent-tolerant bacteria, and to obtain valuable intermediates from these heterocycles. Other recent advances have demonstrated the mechanisms of angular dioxygenation of nitrogen heterocycles by microbes. However, these technologies are not yet available for large-scale applications so future research must investigate proper modifications for industrial applications of these processes. This review focuses on recent progress in understanding how microbes degrade S, N and O heterocycles.

[Changes of mossy fiber sprouting in hippocampus of pentylenetetrazole kindling rats].

OBJECTIVE: To determine the changes of mossy fiber sprouting in hippocampus of pre-kindling and post-kindling rats of chronic epilepsy induced by pentylenetetrazole (PTZ). METHODS: Sixty rats were randomly divided into a control group and a PTZ group (PTZ 30 mg/kg, intraperitoneal injection, once daily). The changes of mossy fiber sprouting in hippocampus of pre-kindling and post-kindling rats were examined by Timm staining. RESULTS: Before the occurrence of convulsion confirmed by behavior and EEG, the mossy fiber sprouting was found in the PTZ group. The grade of the mossy fiber sprouting increased with the gradual establishment of kindling effect. CONCLUSION: Mossy fiber sprouting may play an important role in the onset and development of epilepsy.

Methods for the preparation of a biodesulfurization biocatalyst using Rhodococcus sp.

Several methods to prepare a biodesulfurization (BDS) biocatalyst were investigated in this study using a strain of Rhodococcus sp. 1awq. This bacterium could selectively remove sulfur from dibenzothiophene (DBT) via the "4S" pathway. DBT, dimethylsulfoxide (DMSO), sodium sulphate and mixed sulfur sources were used to study their influence on cell density, desulfurization activity, desulfurization ability, and the cost of biocatalyst production. In contrast to that observed from bacteria cultured in DBT, only partial desulfurization activity of strain 1awq was induced by DBT after cultivation in a medium containing inorganic sulfur as the sole sulfur source. The biocatalyst, prepared from culture with mixed sulfur sources, was found to possess desulfurization activity. With DMSO as the sole sulfur source, the desulfurization activity was shown to be similar to that of bacteria incubated in medium with DBT as the sole sulfur source. The biocatalyst prepared by this method with the least cost could remove sulfur from hydrodesulfurization (HDS)-treated diesel oil efficiently, providing a total desulfurization percent of 78% and suggesting its cost-effective advantage.

[The innate ability of Rhodococcus sp. SDUZAWQ to tolerate sulfur in petroleum].

Removal of sulfur from petroleum can be accomplished by various means. One method is to use microorganisms, such as bacteria. In the present study, strain Rhodococcus sp. SDUZAWQ was employed to test the effects of various concentrations of dibenzothiophene (DBT) and sulfate, had on this removal process. Desulfurization was accomplished, using Basal Salts Medium (BSM), supplemented with 0.2mmol/L DBT and different concentrations of Na2SO4. Growth of SDUZAWQ was pronounced, even when the concentration of DBT was increased to 6mmol/L. Furthermore, it should be noted that the end product of DBT desulfurization, 2 hydroxybiphenyl (2-HBP), was detected as well. This finding was significant because it demonstrated the bacteria' s ability to withstand high concentrations of organosulfur. Dibenzothiophene was utilized when both DBT and Na2SO4 were present in the culture medium. Additionally, 2-HBP was produced. These data are in contrast to previous studies that indicated that DBT could not be metabolized by Rhodococcus sp. in the presence of sulfate. Finally, cloning and sequencing of the gene cluster dszABC, its upstream regulatory sequence and dszD, demonstrated that they share 99%, 100% and 100% with those of R. erythropolis IGTS8, respectively.

Prevalence of hepatitis C infection among intravenous drug users in Shanghai.

AIM: To characterize the prevalence of hepatitis C virus (HCV) infection among Chinese intravenous drug users (IDUs). METHODS: A total of 432 adult IDUs (95 women and 337 men) in Shanghai were included in the study. The third-generation Elecsys Anti-HCV assay (Roche Diagnostics GmbH, Sandhofer Strasse 116, D-68305, Mannheim, Germany) was used to screen for antibodies against HCV. The RIBA strip, a supplemental anti-HCV test with high specificity, was performed on all of the samples that tested positive during the initial screening. All of the anti-HCV positive samples were analyzed with a Cobas TaqMan 48 Analyzer (Roche Diagnostics) for direct detection of HCV RNA. All of the HCV RNA-positive samples were sequenced for genotype determination. RESULTS: The preliminary screening identified 262 (60.6%) subjects who were seropositive for HCV. Of the 62 females and 200 males seropositive subjects, 16 (16.7%) and 65 (19.3%), respectively, were confirmed by RIBA, yielding an overall HCV seropositive rate of 18.8%. Four female (6.5%) and 14 male (7.0%) subjects tested positive for HCV RNA, indicating an active infection rate of 4.2% for the entire study population. The 18 HCV RNA-positive serum samples were genotyped. Seven individuals were genotype 1b, and four were genotype 1a. One individual each was infected with genotypes 2a, 2b and 3a. Four subjects were co-infected with multiple strains: two with genotypes 1a and 2a, and two with genotypes 1b and 2a. The active infection rate among HCV-seropositive individuals was 22.2%, which was significantly lower than most estimates. CONCLUSION: The prevalence of HCV is relatively low among IDUs in Shanghai, with a spontaneous recovery rate much higher than previous estimates.

Alphavirus M1 induces apoptosis of malignant glioma cells via downregulation and nucleolar translocation of p21WAF1/CIP1 protein.

Alphavirus, a genus of arthropod-borne togavirus, is well-known for its pro-apoptotic capability. However, the underlying mechanism remains to be further clarified. Here, we have identified that M1, an alphavirus isolated in 1960s, targeted C6 malignant glioma cells for apoptosis. Flow cytometry analysis showed that more cells enter S-phase post M1 infection, and subsequently undergo a classic apoptosis. To elucidate the mechanism of S-phase arrest and its relationship to apoptosis, we tested the expression of several critical cell cycle regulatory proteins and found elevated phosphorylation of cyclin-dependent kinase 2 (CDK2), decreased expression of cyclin A and proliferating cell nuclear antigen (PCNA). Notably, the protein level of p21(WAF1/CIP1) was downregulated earliest and most effectively among all tested changes of cell cycle regulators, though its mRNA level was strongly upregulated. To evaluate the role of p21(WAF1/CIP1) in S-phase accumulation and subsequent apoptosis, we confirmed that exogenous p21(WAF1/CIP1) overexpression or treatment with roscovitine (a selective chemical inhibitor of CDK2) efficiently protected against apoptosis with a reduced S-phase accumulation. Thus, it is indicated that the downregulation of p21(WAF1/CIP1) mediated C6 apoptosis via overactivation of CDK2. In addition, confocal microscopy showed that p21(WAF1/CIP1) totally translocated to nucleolus during M1-induced C6 apoptosis. Altogether, downregulation and nucleolar translocation of the p21(WAF1/CIP1) protein played an active role in M1-induced C6 apoptosis.