Targeted expression of islet neogenesis associated protein to beta cells enhances glucose tolerance and confers resistance to streptozotocin-induced hyperglycemia

Islet neogenesis associated protein (INGAP) stimulates experimental pancreatic islet growth, as evidenced by elevated markers of beta cell mass, in rodents, dogs and primates. Previous analyses of mice that have a transgenic expression of INGAP targeted to the exocrine pancreas have indicated additional biological activity attributed to INGAP. In this study we report on mice with a targeted expression of INGAP to the islet beta cell. The beta cell transgenic mice (IP-INGAP) showed enhanced normalization of blood glucose during IPGTT. Further, IP-INGAP mice had a significant delay in development of hyperglycemia following a diabetogenic dose of streptozotocin. INGAP conferred beta cell protection and enhanced islet function. Analysis of oxidative stress genes in IP-INGAP mice revealed a decrease in islet expression of the NADPH oxidase, NOX1, in both basal state and in response to pro-inflammatory cytokine stimulation. These data are consistent with a pleiotropic role for INGAP and reveal new pathways to target in the discovery of improved diabetic therapies.     

Heart failure incidence and survival (from the Atherosclerosis Risk in Communities study)

Heart failure (HF) is increasing in prevalence in the United States. Little data exists on race and gender differences in HF incidence rates and case fatality. The Atherosclerosis Risk in Communities (ARIC) cohort is a population-based study from 4 United States communities (1987 to 2002). Prevalent HF cases (n = 750) were identified by self-report and were excluded. Incident HF was defined by the International Classification of Diseases codes for HF (428.0 to 428.9, I50) from a hospitalization (n = 1,206) or death certificate (n = 76). There were 1,282 incident HF cases over 198,417 person-years. The age-adjusted incidence rate (per 1,000 person-years) for Caucasian women, 3.4, was significantly less compared with all other groups (Caucasian men, 6.0; African-American women, 8.1; African-American men, 9.1). Age-adjusted HF incidence rates were greater for African-Americans than Caucasians, but adjustment for confounders attenuated the difference. The adjusted African-American-to-Caucasian hazard ratio was 0.86 (95% confidence interval, 0.70 to 1.06) for men, and similarly, 0.93 (95% confidence interval, 0.46 to 1.90) for women during the second half of follow-up. The hazard ratio for women during the first half of follow-up was 1.79 (95% confidence interval, 1.25 to 2.55). Thirty-day, 1-year, and 5-year case fatalities following hospitalization for HF were 10.4%, 22%, and 42.3%, respectively. African-Americans had a greater 5-year case fatality compared with Caucasians (p <0.05). In conclusion, heart failure incidence rates in African-American women were more similar to those of men than of Caucasian women. The greater HF incidence in African-Americans than in Caucasians is largely explained by African-Americans' greater levels of atherosclerotic risk factors.     

Comparison of Wallstent and Ultraflex stents for palliation of malignant left-sided colon obstruction: a retrospective, case-matched analysis

BACKGROUND: Self-expandable metal stents (SEMSs) are accepted palliation for malignant colon obstruction. Outcomes of different stent types is unknown. OBJECTIVE: Our purpose was to compare outcomes after palliative placement of the Enteral Wallstent (EW) and the Precision Colonic Ultraflex (PCU) stent. DESIGN: Retrospective study of all SEMS placement during a 7-year period. SETTING: Tertiary care academic medical center. PATIENTS: Malignant left-sided colon obstruction in which through-the-scope (TTS) or non-TTS stent placement was possible. MAIN OUTCOME MEASUREMENTS: Technical and clinical success rates, stent-related complications, reintervention. RESULTS: Demographics, degree, site, and cause of obstruction were comparable. Technical difficulties were more frequent with EW than PCU (16% vs 9%, P not significant), insufficient stent expansion and stent misplacement being most common. Relief of obstruction occurred in all patients when placement was technically successful. Mean follow-up was 93 days (range 7-691 days). Early (<7 days) stent occlusion (6% vs 0%, P not significant) and migration (4% vs 0%, P not significant) occurred more frequently in the EW group. Self-limited hematochezia was more common with PCU (20% vs 2%, P = .002). Delayed complications (perforation, stent occlusion, migration, and erosion) occurred significantly more often in the EW group (38% vs 20%). Reintervention was needed more frequently for EW, endoscopic (40% vs 17%, P = .01) and operative (46% vs 26%, P = .03). CONCLUSIONS: Enteral Wallstents and Precision Ultraflex Colonic stents adequately relieve colonic obstruction. Stent dysfunction, stent-related complications, and need for reintervention are higher after EW placement. Precision Colonic Ultraflex stents appear better suited for palliation of left-sided malignant colon obstruction.     

Statin use and incident frailty in women aged 65 years or older: prospective findings from the Women's Health Initiative Observational Study

BACKGROUND: Inflammatory biomarkers have shown consistent associations with disability and frailty in older adults. Statin medications may reduce the incidence the frailty because of their anti-inflammatory effects. This study examines associations between current use, duration, and potency of statin medications and incident frailty in initially nonfrail women 65 years old or older. METHODS: The authors conducted a prospective analysis of data from the Women's Health Initiative Observational Study (WHI-OS) conducted at 40 clinical centers in the United States. Eligible women were nonfrail and 65-79 years old at baseline (n = 25,378). Current statin use at baseline was ascertained through direct inspection of medicine containers during clinic visits. Frailty was ascertained through self-reported indicators and physical measurements at baseline and 3-year clinic contacts. Components of frailty included self-reported low physical function, exhaustion, low physical activity, and unintended weight loss. Multinomial logistic regression models were used to adjust for covariates predicting incident frailty. RESULTS: Among the 25,378 eligible women, 3453 (13.6%) developed frailty by the 3-year follow-up contact. Current statin use had no association with incident frailty (multivariate-adjusted odds ratio [OR] = 1.00; 95% confidence interval [CI], 0.85-1.16). Duration and potency of statin use were also not significantly associated with incident frailty. Among low potency statin users, longer duration of use was associated with reduced risk of frailty (p for trend =.02). A similar pattern of results was observed when frailty was studied in the absence of intervening, incident cardiovascular events. CONCLUSIONS: Overall, incidence of frailty was similar in current statin users and nonusers.     

Circulating endothelial and endothelial progenitor cells in patients with severe sepsis

Elevated circulating endothelial cell (CEC) and circulating endothelial progenitor cell (CEPC) counts may indicate vascular damage and disease status, but data on these cell populations in patients with severe sepsis are limited. This study compared CEC and CEPC counts in patients with and without severe sepsis following intensive care unit (ICU) admission. Venous blood samples were collected within 24 h, 48-72 h, and 120-144 h. Baseline demographics, 28-day mortality, ICU and hospital days, and Sequential Organ Failure Assessment (SOFA) scores were recorded. Patients with (n = 18) and without (n = 28) severe sepsis were balanced for mean age (63.7 and 61.3 years, respectively) and gender. There were no differences in 28-day mortality, ICU days, or hospital days. Baseline SOFA scores were higher in the sepsis group. At 48-72 h, patients with severe sepsis had significantly higher median CEC counts (51.5 vs. 28.0 cells/4 ml of blood, P = 0.02). CEC values for all ICU patients were significantly (P < 0.05) higher than in healthy volunteers. CEPC counts in both cohorts ranged from 0 to > 21 colonies/4 ml blood (mean = 1.13 ± 2.25; median = 0) without significant differences at any time point. This study demonstrates the ability to quantify CECs and CEPCs using consensus methodology. Understanding the relationship between CEC/CEPC counts and outcomes may provide insight into the mechanisms of endothelial cell changes in severe sepsis.     

Crystal structure of a near-full-length archaeal MCM: Functional insights for an AAA+ hexameric helicase

The minichromosome maintenance protein (MCM) complex is an essential replicative helicase for DNA replication in Archaea and Eukaryotes. Whereas the eukaryotic complex consists of 6 homologous proteins (MCM2–7), the archaeon Sulfolobus solfataricus has only 1 MCM protein (ssoMCM), 6 subunits of which form a homohexamer. Here, we report a 4.35-Å crystal structure of the near-full-length ssoMCM. The structure shows an elongated fold, with 5 subdomains that are organized into 2 large N- and C-terminal domains. A near-full-length ssoMCM hexamer generated based on the 6-fold symmetry of the N-terminal Methanothermobacter thermautotrophicus (mtMCM) hexamer shows intersubunit distances suitable for bonding contacts, including the interface around the ATP pocket. Four unusual β-hairpins of each subunit are located inside the central channel or around the side channels in the hexamer. Additionally, the hexamer fits well into the double-hexamer EM map of mtMCM. Our mutational analysis of residues at the intersubunit interfaces and around the side channels demonstrates their critical roles for hexamerization and helicase function. These structural and biochemical results provide a basis for future study of the helicase mechanisms of the archaeal and eukaryotic MCM complexes in DNA replication.     

Activated partial thromboplastin time and risk of future venous thromboembolism

Background

Lower activated partial thromboplastin times are associated with higher levels of some coagulation factors and may represent a procoagulant tendency.

Methods

In the Atherosclerosis Risk in Communities study, we studied the 13-year risk of venous thromboembolism in relation to baseline activated partial thromboplastin time in 13,880 individuals. We also studied 258 venous thromboembolism cases and 589 matched controls with measurements of additional coagulation factors.

Results

After adjustment for demographics and procoagulant factors reflected in the activated partial thromboplastin time (fibrinogen, factors VIII, IX, and XI, and von Willebrand factor), participants in the lowest 2 quartiles of activated partial thromboplastin time compared with the fourth quartile had 2.4-fold (95% confidence interval [CI], 1.4-4.2) and 1.9-fold (95% CI, 1.1-3.2) higher risks of venous thromboembolism. The risk associated with activated partial thromboplastin times below the median was higher for idiopathic (odds ratio 5.5; 95% CI, 2.0-15.5) than secondary venous thromboembolism (odds ratio 1.74; 95% CI, 0.88-3.43). Subjects with both activated partial thromboplastin times below the median and factor V Leiden were 12.6-fold (95% CI, 5.7-28.0) more likely to develop venous thromboembolism compared with those with neither risk factor (P interaction <.01). A lower activated partial thromboplastin time also added to the thrombosis risk associated with obesity and elevated D-dimer.

Conclusion

A single determination of the activated partial thromboplastin time below the median increased the risk of future venous thromboembolism. Findings were independent of coagulation factor levels, and a low activated partial thromboplastin time added to the risk associated with other risk factors.     

Disruption of Tsc2 in pancreatic beta cells induces beta cell mass expansion and improved glucose tolerance in a TORC1-dependent manner

Regulation of pancreatic beta cell mass and function is a major determinant for the development of diabetes. Growth factors and nutrients are important regulators of beta cell mass and function. The signaling pathways by which these growth signals modulate these processes have not been completely elucidated. Tsc2 is an attractive candidate to modulate these processes, because it is a converging point for growth factor and nutrient signals. In these experiments, we generated mice with conditional deletion of Tsc2 in beta cells (betaTsc2(-/-)). These mice exhibited decreased glucose levels and hyperinsulinemia in the fasting and fed state. Improved glucose tolerance in these mice was observed as early as 4 weeks of age and was still present in 52-week-old mice. Deletion of Tsc2 in beta cells induced expansion of beta cell mass by increased proliferation and cell size. Rapamycin treatment reversed the metabolic changes in betaTsc2(-/-) mice by induction of insulin resistance and reduction of beta cell mass. The reduction of beta cell mass in betaTsc2(-/-) mice by inhibition of the mTOR/Raptor (TORC1) complex with rapamycin treatment suggests that TORC1 mediates proliferative and growth signals induced by deletion of Tsc2 in beta cells. These studies uncover a critical role for the Tsc2/mTOR pathway in regulation of beta cell mass and carbohydrate metabolism in vivo.     

Ethanol Inhibits Spontaneous Activity of Central Nucleus of the Amygdala Neurons but Does Not Impair Retention in the Passive-Avoidance Task

BACKGROUND: Behavioral studies using pharmacological manipulations that increase neuronal activity of the central nucleus of the amygdala (CeA) have implicated the CeA in enhancement of memory modulation. To date, however, there has been a dearth of studies investigating the effect of a drug that decreases CeA activity on memory modulation-a drug that inhibits the neuronal activity of the CeA might be expected to impair memory modulation. To determine whether ethanol inhibits CeA activity and, if so, whether decreased CeA activity is associated with impairment of memory modulation, this study investigated the effect of ethanol on spontaneous single-unit activity of CeA neurons and retention in the passive-avoidance task. METHODS: The effect of ethanol (0.35, 0.75, 1.5, 2.5 g/kg) was determined on spontaneously firing neurons in the CeA in urethane-anesthetized rats by use of standard in vivo single-unit electrophysiological recording techniques. Additionally, the effect of ethanol when administered immediately after training in a standard passive-avoidance task was determined on retention the following day. RESULTS: Ethanol profoundly inhibited spontaneous CeA firing rates in urethane-anesthetized rats at all doses tested. Maximal inhibition was related to dose. Each dose of ethanol significantly inhibited CeA activity within 15 min of administration; within 35 min of administration, 0.75 g/kg of ethanol inhibited CeA activity by 65.2%, and the highest dose (2.5 g/kg) produced nearly complete suppression of CeA activity (81.3%). Although ethanol markedly inhibited CeA activity, these same doses of ethanol failed to impair retention in the passive-avoidance task: 0.35, 0.75, 1.5, and 2.5 g/kg of ethanol, administered immediately after training, failed to alter latency to step-through the following day. CONCLUSIONS: These results show that ethanol profoundly inhibits spontaneous CeA activity and suggest that inhibition of the CeA is not sufficient to impair retention in the passive-avoidance task.     

Pentobarbital for severe gamma-butyrolactone withdrawal

STUDY OBJECTIVE: Gamma-hydroxybutyrate (GHB) and gamma-butyrolactone (GBL) have become popular drugs of abuse. Acute overdose with either agent results in a well-recognized syndrome of central nervous system and respiratory depression. Recently, a withdrawal syndrome has been described for GHB. We report a severe form of GBL withdrawal, characterized by delirium, psychosis, autonomic instability, and resistance to benzodiazepine therapy. METHODS: We performed a chart review of consecutive admissions for GBL withdrawal in a regional toxicology treatment center. RESULTS: During a 6-month period, 5 patients presented with severe withdrawal attributed to abrupt GBL discontinuation. Patients manifested tachycardia, hypertension, paranoid delusions, hallucinations, and rapid fluctuations in sensorium. Test results for ethanol and routine drugs of abuse were negative. Initial treatment with high doses of lorazepam proved ineffective. Pentobarbital was then administered, resulting in excellent control of behavioral, autonomic, and psychiatric symptoms and in rapid reduction or avoidance of benzodiazepines. Median hospital stay was 5 days. No patient had respiratory depression or required mechanical ventilation. Patients were discharged on tapering doses of benzodiazepines or pentobarbital and were free of psychotic symptoms at follow-up. CONCLUSION: GBL discontinuation can result in severe withdrawal, necessitating ICU admission. Pentobarbital may be more effective than benzodiazepines at controlling delirium in patients with abnormal vital signs, paranoid delusions, and hallucinations as a result of GBL withdrawal.