SUMMARYPurpose: The role of gap junctions in seizures is an area of intense research. Many groups have reported anticonvulsant effects of gap junction blockade, strengthening the case for a role for gap junctions in ictogenesis. The cerebral cortex is underrepresented in this body of research. We have investigated the effect of gap junction blockade on seizure-like activity in rat and mouse cerebral cortex slices. Methods: Seizure-like activity was induced by perfusing with low-magnesium artificial cerebrospinal fluid. The effect of three gap junction blockers was investigated in rat cortical slices; quinine (200 and 400 lM), quinidine (100 and 200 lM), and carbenoxolone (100 and 200 lM). In addition, the effect of mefloquine was investigated in wild-type mice and connexin36 knockout mice. The data were analyzed for the effect on frequency and amplitude of seizure-like events.Results: Paradoxical excitatory effects on seizurelike activity were observed for all three agents in rat cortical slices. Quinine (200 lM) and carbenoxolone (100 lM) increased both the frequency and amplitude of seizure-like events. Quinidine (100 lM) increased the frequency of events. Higher doses of quinine (400 lM) and carbenoxolone (200 lM) had biphasic excitatory-inhibitory effects. Similar excitatory effects were observed in adult wild-type mouse cortical slices perfused with mefloquine (5 lM or 10 lM), but were absent in slices from connexin36-deficient mice. Discussion: In conclusion, we have shown a paradoxical proseizure effect of pharmacologic gap junction blockade in a cortical model of seizurelike activity. We suggest that this effect is probably due to a disruption of inhibitory interneuron coupling secondary to connexin36 blockade.

Purpose: Specific markers of circulating tumor cells may be informative in managing lung cancer.Because the RE-1silencing transcription factor (REST/NRSF) is a transcriptional repressor that is inactivated in neuroendocrine lung cancer, we identified REST-regulated transcripts (CHGA, CHGB, SCG3,VGF, and PCSK1) for evaluation as biomarkers in peripheral blood. Experimental Design: Transcripts were screened across lung cancer and normal cell lines. Candidates were assessed by reverse transcription-PCR and hybridization of RNA extracted from the peripheral blood of 111 lung cancer patients obtained at clinical presentation and from 27 cancer-free individuals. Results: Expression profiling revealed multiple chromogranin transcripts were readily induced on RESTdepletion, most notably SCG3 was induced >500-fold.The SCG3 transcript was also overexpressed by 12,000-fold in neuroendocrine compared with nonneuroendocrine lung cancer cells. In peripheral blood of lung cancer patients and cancer-free individuals, we found that SCG3 was more tumor-specific and more sensitive than other chromogranin transcripts as a biomarker of circulating tumor cells. Overall, 36% of small cell lung cancer (SCLC) and 16% of non-SCLC patients scored positively for normalized SCG3 transcript. This correlated with worse survival among SCLC patients with limited disease (n = 33; P = 0.022) but not extensive disease (n = 29; P = 0.459). Interestingly, the subcohort of 6 SCLC patients with resistance to platinum/ etoposide chemotherapy all scored positively for peripheral blood SCG3 transcript (P = 0.022). Conclusions: SCG3 mRNA, a component of the REST-dependent neurosecretory transcriptional profile, provides a sensitive prognostic biomarker for noninvasive monitoring of neuroendocrine lung cancer.

Sleigh, Connexin36 knockout mice display increased sensitivity to pentylenetetrazolinduced seizure-like behaviors, Brain Research (2010),

IL-1R antagonist (IL-1Ra) is required for adequate host defense in invasive pneumococcal disease (IPD). The minor allele of an IL1RN gene (C/T) promoter polymorphism (rs4251961) has been shown to be associated with decreased IL-1Ra production in healthy adults. We genotyped 299 children with IPD, and examined 19 IL1RN haplotype-tagging single-nucleotide polymorphisms. Human embryonic kidney HEK293(T) cells were transfected with the promoter reporter plasmid pGL3p containing either allelic variant C (pGL3pCC) or T (pGL3pTT) with or without cotransfection with an expression construct overexpressing the globin transcription factor GATA-1. Plasma IL-1Ra concentrations were significantly higher in nonsurvivors compared with survivors (p < 0.0005), and the C allele of rs4251961 was associated with a significant increase in plasma IL-1Ra concentrations (p = 0.01) during the acute illness of IPD. These findings were validated in a cohort of 276 treatment-naive HIV-infected adults, with borderline significance (p = 0.058). Functional analyses demonstrated that the activity of the promoter constructs containing the T allele increased ~6-fold as compared with basal activity, and that containing the C allele by ~9-fold (p < 0.001) in the presence of GATA-1. Our findings suggest that the IL-1Ra single-nucleotide polymorphism rs4251961 plays a key role in the pathophysiology of IPD and in other human infections.

Stress hormone and sleep differences in a competition versus training setting are yet to be evaluated in elite female team-sport athletes. The aim of the current study was to evaluate salivary cortisol and perceptual stress markers during competition and training and to determine the subsequent effects on sleep indices in elite female athletes. Ten elite female netball athletes (mean ± SD; age: 23 ± 6 years) had their sleep monitored on three occasions; following one netball competition match (MATCH), one netball match simulation session (TRAIN), and one rest day (CONTROL). Perceived stress values and salivary cortisol were collected immediately pre- (17:15 pm) and post-session (19:30 pm), and at 22:00 pm. Sleep monitoring was performed using wrist actigraphy assessing total time in bed, total sleep time (TST), efficiency (SE%), latency, sleep onset time and wake time. Cortisol levels were significantly higher (p < .01) immediately post MATCH compared with TRAIN and CONTROL (mean ± SD; 0.700 ± 0.165, 0.178 ± 0.127 and 0.157 ± 0.178 μg/dL, respectively) and at 22:00 pm (0.155 ± 0.062, 0.077 ± 0.063, and 0.089 ± 0.083 μg/dL, respectively). There was a significant reduction in TST (-118 ± 112 min, p < .01) and SE (-7.7 ± 8.5%, p < .05) following MATCH vs. TRAIN. Salivary cortisol levels were significantly higher, and sleep quantity and quality were significantly reduced, following competition when compared to training and rest days.