Altered axon initial segment in hippocampal newborn neurons, associated with recurrence of temporal lobe epilepsy in rats.

Hippocampal neurogenesis in temporal lobe epilepsy (TLE) may result in alteration of the excitability of neurons, which contributes to spontaneous recurrent seizures. Axon initial segment (AIS) structural and functional plasticity is important in the control of neuronal excitability. It remains to be elucidated whether the plasticity of AIS occurs in hippocampal newly­generated neurons that are involved in recurrent seizures following pilocarpine­induced status epilepticus (SE). The present study first established a pilocarpine­induced TLE rat model to assess the features of newborn neurons and AIS plasticity alterations using double immunofluorescence staining of Ankyrin G and doublecortin (DCX). AIS plasticity alterations include length and distance from soma in the hippocampal newly­generated neurons post­SE. The results of the present study demonstrated that pilocarpine­induced epileptic rats exhibited aberrant hippocampal neurogenesis and longer DCX­labeled cell dendrites in the dentate gyrus. Pilocarpine­induced epileptic rats demonstrated shortened lengths of AIS and an increased distance from the soma in hippocampal newborn neurons. Mibefradil, a T/L­type calcium blocker, reversed the alterations in length and position of AIS in hippocampal newborn neurons post­SE, accompanied by decreased long­term seizure activity without increased aberrant neurogenesis. These findings indicate that the plasticity of AIS in hippocampal neurogenesis may have profound consequences in epilepsy, at least in animals.

Progesterone is neuroprotective by inhibiting cerebral edema after ischemia.

Ischemic edema can alter the structure and permeability of the blood-brain barrier. Recent studies have reported that progesterone reduces cerebral edema after cerebral ischemia. However, the underlying mechanism of this effect has not yet been elucidated. In the present study, progesterone effectively reduced Evans blue extravasation in the ischemic penumbra, but not in the ischemic core, 48 hours after cerebral ischemia in rats. Progesterone also inhibited the down-regulation of gene and protein levels of occludin and zonula occludens-1 in the penumbra. These results indicate that progesterone may effectively inhibit the down-regulation of tight junctions, thereby maintaining the integrity of the blood-brain barrier and reducing cerebral edema.

Determination of the normative values of the masseter muscle by single-fiber electromyography in myasthenia gravis patients.

The purpose of this study is to obtain normative values of the masseter muscle of myasthenia gravis (MG) patients and healthy volunteers by single-fiber electromyography (SFEMG). Stimulation of SFEMG in the masseter muscle was studied in 15 healthy volunteers (men 8, women 7; mean age 40.2, range 21-77) and 30 patients affected by MG (men 16, women 14; mean age 42.8, range 12-75). The mean consecutive difference (MCD) of the individual fiber and the mean MCD per study were determined in the normal group. We recommend the upper normal limit for the individual fibers of jitter and the mean MCD per study in the healthy Chinese adults of 33 µs and 22 µs respectively. Furthermore, in the MG group, the percentage of jitter > upper normal limit jitter and the impulse blocking percentage were detected, which were all significantly different compared to the normal control group (P < 0.01). The overall sensitivity was 90%, with the abnormality in 6 of the 9 ocular MG patients and 100% abnormality in the generalized MG patients. The masseter muscle SFEMG has a high degree of sensitivity. The masseter should be considered for SFEMG in the diagnosis of MG, and added routinely to the tested muscles.

Effect of peroxisome proliferator-activated receptor gamma agonist on heart of rabbits with acute myocardial ischemia/reperfusion injury.

OBJECTIVE: To explore protective effect of rosiglitazone on myocardial ischemia reperfusion injury. METHODS: A total of 48 male SD rats were randomly divided into control group (A), I/R group(B), high dose of rosiglitazone (C), low dose of rosiglitazone (D). Plasm concentration of creatine kinase (CK), CK-MB, hsCRP, Superoxide dismutase (SOD), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), nitric oxide (NO) and endothelin (ET) were measured 1 h later after I/R. 24 h after I/R hearts were harvested to observe pathological and ultrastructural changes. Immunohistochemistry and western blotting was used to test CD40 expression in myocardial tissue. Area of myocardial infarction were tested, arrhythmia rate during I/R was recorded. RESULTS: Plasm concentration of creatine kinase (CK), CK-MB, hsCRP, NO, MDA and ET were decreased in group C, D compared with group B. Plasm concentration of T-SOD and GSH-Px was increased significantly in group C, D compared with group B. Compared with group B, pathological and ultrastructural changes in group C, D were slightly. Myocardial infarction area and arrhythmia rate were lower in group C, D compare with group B. CONCLUSIONS: Rosiglitazone can protect myocardium from I/R injury by enhancing T-SOD and GSH-Px concentration, inhibit inflammatory reaction, improve endothelial function, reduce oxidative stress and calcium overload.

[The relationship of P47phox C923T (Ala308Val) polymorphism to cerebral infarction and its effect on plasma lipid levels].

OBJECTIVE: To investigate the relationship between C923T (Ala308Val) polymorphism in the exon10 of P47(phox) gene and cerebral infarction and to evaluate the effect of C923T polymorphism on plasma lipid levels. METHODS: Peripheral blood samples were collected from 110 patients with cerebral infarction, 100 sex and age-matched healthy controls, and 102 members of 10 cerebral infarction pedigrees 19 of which were cerebral infarction patients. The polymorphism in P47(phox) gene was determined by PCR-single strand conformation polymorphism analysis and DNA sequencing. Plasma lipid levels were measured by routine methods. RESULTS: Three gene types, CC, CT, and TT were found in the C923T (Ala308Val) polymorphism site. No statistically significant differences were found in the frequencies of genotypes and alleles of C923T polymorphism between the controls and cerebral infarction patients (all P > 0.05). The serum levels of triglyceride of cerebral infarction patients and controls with the CT genotype were markedly higher than those of the cerebral infarction patients and controls with the CC genotype (both P < 0.05). CONCLUSION: There is no association between the C923T polymorphism and cerebral infarction. C923Tpolymorphism is associated with plasma lipid metabolism.

[COX-2 and mPGES-1 expression in carotid atherosclerotic plaques].

OBJECTIVE: To investigate the changes in the expressions of inducible cyclooxygenase type 2 (COX-2) and membrane associated prostaglandin E-1(mPGES-1) in human carotid atherosclerotic plaques and to explore possible mechanisms of inflammatory process involved in plaque stability. METHODS: The mRNA and protein levels of COX-2 and mPGES-1 were compared between minimally and grossly atherosclerotic arterial tissues. COX-2 and mPGES-1 gene expression were established by immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) in 10 mesenchymal artery controls and 24 atherosclerotic specimens. Presence of COX-2 and mPGES-1 protein was assessed by Western blotting. RESULTS: Immunohistochemical staining showed that the COX-2 and mPGES-1 immunoreactive substances were present in the cytoplasm of smooth muscle cell. Compared with the control group, immunostaining positive cells increased in carotid atherosclerotic plaque group. COX-2 and mPGES-1 gene expression was significantly elevated in atherosclerotic plaques (P< 0.05, respectively). The increased mRNA and protein levels of COX-2 and mPGES-1 were correlated in atherosclerotic tissue (P< 0.05). The mRNA and protein levels of COX-2 and mPGES-1 related to degree of pathological damage in atherosclerotic tissue (P< 0.05). COX-2 and mPGES-1 were not found in the control group (mesenteric vascular walls). CONCLUSION: COX-2 and mPGES-1 expression in plaques is significantly higher than that in the control group. These findings suggests that COX-2 and mPGES-1 might play a role in pathogenesis of atheroscleros and modulation of inflammatory process involved in plaque stability, and COX-2 may have proinflammatory enzyme properties.

[Lecithin-cholesterol acyltransferase gene 608C/T polymorphism associated with atherosclerotic cerebral infarction].

OBJECTIVE: To explore the distribution of lecithin-cholesterol acyltransferase gene (LCAT) 608C/T polymorphism in Chinese Han population and the relationship of the polymorphism association with the occurrence of atherosclerotic cerebral infarction. METHODS: The lecithin:cholesterol acyltransferase gene 608C/T polymorphism is identified by polymerase chain reaction (PCR), single-strand conformation polymorphism (SSCP)and restriction fragment length polymorphism (RFLP) in 150 patients with ACI and 122 healthy controls matching age and sex. RESULTS: The distribution of LCAT 608C/T gene polymorphism was in accordance with Hardy-Weinberg equilibrium. The CT genotype frequency (14.0%) and T allele frequency (7.0%) in ACI group were significantly higher than those in control group (P<0.05). The concentration of high density lipoprotein cholesterol (HDL-C) in 608CC subgroups were significantly higher than those in 608CT subgroups both in ACI group and in control group (P<0.05). CONCLUSION: The LCAT 608C/T polymorphism is possibly a predisposing factor in ACI happening of Chinese Han population. T allele frequency is possibly concerned with the metabolism of HDL-C.