Seizure Outcomes and Predictors of Recurrent Post-Stroke Seizure: A Retrospective Observational Cohort Study

Background

Seizure is a common complication after stroke (termed “post-stroke seizure,” PSS). Although many studies have assessed outcomes and risk factors of PSS, no reliable predictors are currently available to determine PSS recurrence. We compared baseline clinical characteristics and post-stroke treatment regimens between recurrent and non-recurrent PSS patients to identify factors predictive of recurrence.

Methods

Consecutive PSS patients admitted to our stroke center between January 2011 and July 2013 were monitored until February 2014 (median 357 days; IQR, 160–552) and retrospectively evaluated for baseline clinical characteristics and PSS recurrence. Cumulative recurrence rates at 90, 180, and 360 days post-stroke were estimated by Kaplan—Meier analysis. Independent predictors of recurrent PSS were identified by Cox proportional-hazards analysis.

Results

A total of 104 patients (71 men; mean age, 72.1 ± 11.2 years) were analyzed. PSS recurred in 31 patients (30%) during the follow-up. Factors significantly associated with PSS recurrence by log-rank analysis included previous PSS, valproic acid (VPA) monotherapy, polytherapy with antiepileptic drugs (AEDs), frontal cortical lesion, and higher modified Rankin Scale score at discharge (all p < 0.05). Independent predictors of recurrent PSS were age <74 years (HR 2.38, 95% CI 1.02–5.90), VPA monotherapy (HR 3.86, 95% CI 1.30–12.62), and convulsions on admission (HR 3.87, 95% CI 1.35–12.76).

Conclusions

Approximately one-third of PSS patients experienced seizure recurrence within one year. The predictors of recurrent PSS were younger age, presence of convulsions and VPA monotherapy. Our findings should be interpreted cautiously in countries where monotherapy with second-generation AEDs has been approved because this study was conducted while second-generation AEDs had not been officially approved for monotherapy in Japan.     

Oral administration of antigen does not influence the proliferation and IFN-γ production of responsive CD8+ T cells but enables to establish T cell clones with different lymphokine production profile.

Feeding of a whole casein diet, which abolished the α_s1-casein-specific proliferation and IFN-γ productivity of CD⁴⁺ T cells, did not affect the proliferative response of CD8⁺ T cells with regard to the antigen dose response, cell dose response, kinetics of the proliferation and epitope specificity, as well as IFN-γ production. To assess the characteristics of the CD8⁺ T cells, we established α_s1-casein-specific CD8⁺ T cell clones from both casein-fed and control mice. The established clones produced different amount of IFN-γ and IL-10, and one clone derived from the casein-fed mice produced a remarkable amount of IL-10. The clones from casein-fed mice produced considerable amounts of TGF-β, while those from control mice produced only small amounts. The possible role of CD8⁺ T cells in oral tolerance is discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Role of Trehalose Synthesis in Ralstonia syzygii subsp. indonesiensis PW1001 in Inducing Hypersensitive Response on Eggplant (Solanum melongena cv. Senryo-nigou)

Ralstonia syzygii subsp. indonesiensis (Rsi, former name: Ralstonia solanacearum phylotype IV) PW1001, a causal agent of potato wilt disease, induces hypersensitive response (HR) on its non-host eggplant (Solanum melongena cv. Senryo-nigou). The disaccharide trehalose is involved in abiotic and biotic stress tolerance in many organisms. We found that trehalose is required for eliciting HR on eggplant by plant pathogen Rsi PW1001. In R. solanacearum, it is known that the OtsA/ OtsB pathway is the dominant trehalose synthesis pathway, and otsA and otsB encode trehalose-6-phosphate (T6P) synthase and T6P phosphatase, respectively. We generated otsA and otsB mutant strains and found that these mutant strains reduced the bacterial trehalose concentration and HR induction on eggplant leaves compared to wild-type. Trehalose functions intracellularly in Rsi PW1001 because addition of exogenous trehalose did not affect the HR level and ion leakage. Requirement of trehalose in HR induction is not common in R. solanacearum species complex because mutation of otsA in Ralstonia pseudosolanacearum (former name: Ralstonia solanacearum phylotype I) RS1002 did not affect HR on the leaves of its non-host tobacco and wild eggplant Solanum torvum. Further, we also found that each otsA and otsB mutant had reduced ability to grow in a medium containing NaCl and sucrose, indicating that trehalose also has an important role in osmotic stress tolerance.     

Birth of normal calves resulting from bovine oocytes matured, fertilized, and cultured with cumulus cells in vitro up to the blastocyst stage

Bovine oocytes matured in vitro were fertilized in high proportions (92% of matured oocytes) by sperm capacitated with Ca ionophore A23187. Eight percent of inseminated oocytes that were denuded 96 h after insemination developed to the morula stage when cultured for 6-120 h after insemination with cumulus cells from the original oocytes. Inseminated oocytes denuded 96 h after insemination developed to the blastocyst stage when cultured with or without cumulus cells or in the conditioned medium from 96 h to 168-216 h after insemination (9.0%, 8.1%, and 6.8% of inseminated oocytes respectively). Six frozen-thawed blastocysts were transferred nonsurgically to 3 recipients (2 embryos/recipient). Two of the 3 recipients became pregnant, with one delivering live twins at term. Seven fresh blastocysts were transferred nonsurgically to 6 recipients (1-2 embryos/recipient). Three of the 6 recipients became pregnant, with 2 delivering live calves.     

Involvement of vesicular trafficking system in membrane targeting of the progeny influenza virus genome

The genome of influenza type A virus consists of single-stranded RNAs of negative polarity. Progeny viral RNA (vRNA) replicated in the nucleus is nuclear-exported, and finally transported to the budding site beneath the plasma membrane. However, the precise process of the membrane targeting of vRNA is unclear, although viral proteins and cytoskeleton are thought to play roles. Here, we have visualized the translocation process of progeny vRNA using fluorescence in situ hybridization method. Our results provide an evidence of the involvement of vesicular trafficking in membrane targeting of progeny vRNA independent of that of viral membrane proteins.     

A novel glucokinase regulator in pancreatic beta cells: precursor of propionyl-CoA carboxylase beta subunit interacts with glucokinase and augments its activity

A glucokinase regulatory protein has been reported to exist in the liver, which suppresses enzyme activity in a complex with fructose 6-phosphate, whereas no corresponding protein has been found in pancreatic beta cells. To search for such a protein in pancreatic beta cells, we screened for a cDNA library of the HIT-T15 cell line with the cDNA of glucokinase from rat islet by the yeast two hybrid system. We detected a cDNA encoding the precursor of propionyl-CoA carboxylase beta subunit (pbetaPCCase), and glutathione S-transferase pull-down assay illustrated that pbetaPCCase interacted with recombinant rat islet glucokinase and with glucokinase in rat liver and islet extracts. Functional analysis indicated that pbetaPCCase decreased the K(m) value of recombinant islet glucokinase for glucose by 18% and increased V(max) value by 23%. We concluded that pbetaPCCase might be a novel activator of glucokinase in pancreatic beta cells.     

Interferon-Tau Attenuates Uptake of Nanoparticles and Secretion of Interleukin-1β in Macrophages

Background

Type I interferons (IFNs), including IFN-alpha (IFNA) and IFN-beta (IFNB), have anti-inflammatory properties and are used to treat patients with autoimmune and inflammatory disorders. However, little is known of the role of IFN-tau (IFNT), a type I IFN produced by ruminant animals for inflammation. Because IFNB has recently been shown to inhibit nucleotide-binding oligomerization domain-like receptor, pyrin domain-containing 3 (NLRP3) inflammasome activation and subsequent secretion of the potent inflammatory cytokine interleukin (IL)-1β, we examined the effects of ruminant IFNT on NLRP3 inflammasome-mediated IL-1β secretion in human THP-1 macrophages.

Methods and Results

IFNT dose-dependently inhibited IL-1β secretion induced by nano-silica, a well-known activators of NLRP3 inflammasomes, in human macrophages primed with lipopolysaccharide (LPS, TLR4 agonist) and Pam3CSK4 (TLR1/2 agonist). IFNT also suppressed phagocytosis of nano-silica and reactive oxygen species (ROS) generation. Western blot analysis showed that IFNT inhibited both pro-IL-1β and mature IL-1β. In addition, real-time RT-PCR analysis showed that IFNT suppressed IL-1β mRNA expression induced by LPS and Pam3CSK4. Although nano-silica particles did not induce IL-10 secretion, IFNT induced IL-10 secretion in a dose-dependent manner. Furthermore, IFNT-suppressed IL-1β secretion was restored by anti-IL-10 neutralizing antibody.

Conclusions

Ruminant IFNT inhibits NLRP3 inflammasome-driven IL-1β secretion in human macrophages via multiple pathways, including the uptake of nano-silica particles, generation of ROS, and IL-10-mediated inhibition of pro-IL-1β induction. It may be a therapeutic alternative to IFNA and IFNB.     

Pigment cell-specific expression of the tyrosinase gene in ascidians has a different regulatory mechanism from vertebrates

Tyrosinase is the key enzyme required for the synthesis of melanin pigments. Sequence comparison and functional analysis of the 5' upstream regions of vertebrate tyrosinase genes have revealed the importance of conserved E-box motifs in regulating their specific expression in pigment cells, optic cup-derived retinal pigment epithelium (RPE) and neural crest-derived melanocytes. In ascidians (more basal protochordates), two pigment cells that resemble vertebrate RPE cells are formed and specifically express the orthologous tyrosinase gene (HrTyr) in the cerebral vesicle located at the anterior end of the neural tube. To define regulatory sequences required for pigment cell-lineage-specific expression of HrTyr during embryogenesis, a series of mutations of the 5' upstream region of HrTyr were fused to the lacZ reporter gene and were microinjected into fertilized eggs. We found that the -152bp upstream of the translational start site is essential for expression in pigment cell precursors of tailbud-stage embryos. Further, additional positive and unique restriction elements were identified in the region up to -1.8kb. Surprisingly, in the -152bp minimal promoter or in other regions with regulatory activities, there are no E-box motifs or sequences correlating with other conserved elements regulating vertebrate tyrosinase promoters. The possibility that Pax proteins regulate HrTyr expression is also discussed.     

High sensitivity of RBL-2H3 cells to cadmium and manganese: an implication of the role of ZIP8

Cellular incorporation of Cd involves multiple transport systems for other metals such as Fe, Zn, Mn, and Ca. Metal transporters including divalent metal transporter 1, Zrt/Irt-related protein (ZIP) 8, and ZIP14, and certain types of voltage-dependent Ca channels have been shown to be involved in cellular Cd uptake. However, tissue- or cell-specific roles of these metal transporters in the accumulation and toxicity of Cd remains unclear. In the present study, we compared the sensitivity to and accumulation of Cd, Mn, and Zn among four types of rat cell lines. Rat basophilic leukemia RBL-2H3 cells showed the highest sensitivity to Cd and Mn due to the highest accumulation of Cd and Mn among the four cell lines. The high accumulation of Cd and Mn was caused by high uptake rates of Cd and Mn. Since relatively high expression of ZIP8 and ZIP14 was found in RBL-2H3 cells, siRNAs of ZIP8 and ZIP14 were transfected into RBL-2H3 cells. The knockdown of ZIP8, but not of ZIP14, significantly reduced the uptake rates of Cd and Mn in RBL-2H3 cells, especially in the presence of bicarbonate. These results suggest that the high expression of ZIP8, which is known to have affinities for both Cd and Mn, resulted in high accumulation of Cd and Mn, leading to high sensitivity to these metals in RBL-2H3 cells. Thus, RBL-2H3 cells may serve as a good model for clarifying the mechanisms of Cd and Mn transport via ZIP8.