Safety evaluation of probiotic bifidobacteria by analysis of mucin degradation activity and translocation ability

Although probiotic-containing nutrient formulas for infants and toddlers have become very popular, some adverse effects related to translocation of probiotic strains have been reported. We assessed the safety of probiotic bifidobacteria that have been used in clinical investigations and proven to have beneficial effects, by analyzing mucin degradation activity and translocation ability. Mucin degradation activities of three probiotic bifidobacteria strains; Bifidobacterium longum BB536, Bifidobacterium breve M-16V and Bifidobacterium infantis M-63, were evaluated by three in vitro tests comprising growth in liquid medium, SDS-PAGE analysis of degraded mucin residues, and degradation assay in Petri dish. All test strains and control type strains failed to grow in the liquid medium containing mucin as the only carbon source, although good growth was obtained from fecal sample. In the SDS-PAGE analyses of mucin residues and observation of mucinolytic zone in agar plate, the three test strains also showed no mucin degradation activity as the type strains, although fecal sample yielded positive results. In another study, a high dose of B. longum BB536 was administered orally to conventional mice to examine the translocation ability. No translocation into blood, liver, spleen, kidney and mesenteric lymph nodes was observed and no disturbance of epithelial cells and mucosal layer in the ileum, cecum and colon was detected, indicating that the test strain had no translocation ability and induced no damage to intestinal surface. These results resolve the concern about bacterial translocation when using bifidobacteria strains as probiotics, which have been tested in various clinical trials, supporting the continuous use of these probiotic strains without anxiety.     

Effects of fasting on thermoregulatory processes and the daily oscillations in rats

To investigate the mechanism involved in the reduction of body core temperature (T(core)) during fasting in rats, which is selective in the light phase, we measured T(core), surface temperature, and oxygen consumption rate in fed control animals and in fasted animals on day 3 of fasting and day 4 of recovery at an ambient temperature (T(a)) of 23 degrees C by biotelemetry, infrared thermography, and indirect calorimetry, respectively. On the fasting day, 1) T(core) in the light phase decreased (P < 0.05) from the control; however, T(core) in the dark phase was unchanged, 2) tail temperature fell from the control (P < 0.05, from 30.7 +/- 0.1 to 23.9 +/- 0.1 degrees C in the dark phase and from 29.4 +/- 0.1 to 25.2 +/- 0.2 degrees C in the light phase), 3) oxygen consumption rate decreased from the control (P < 0.05, from 24.37 +/- 1.06 to 16.24 +/- 0.69 ml. min(-1). kg body wt(-0.75) in the dark phase and from 18.91 +/- 0.64 to 14.00 +/- 0.41 ml. min(-1). kg body wt(-0.75) in the light phase). All these values returned to the control levels on the recovery day. The results suggest that, in the fasting condition, T(core) in the dark phase was maintained by suppression of the heat loss mechanism, despite the reduction of metabolic heat production. In contrast, the response was weakened in the light phase, decreasing T(core) greatly. Moreover, the change in the regulation of tail blood flow was a likely mechanism to suppress heat loss.     

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.     

Activation of p38 Mitogen-Activated Protein Kinase in Gaucher’s Disease

Gaucher’s disease is caused by defects in acid β-glucosidase 1 (GBA1) and has been also proposed as an inflammatory disease. GBA1 cleaves glucosylceramide to form ceramide, an established bioactive lipid, and defects in GBA1 lead to aberrant accumulation in glucosylceramide and insufficient formation of ceramide. We investigated if the pro-inflammatory kinase p38 is activated in Gaucher’s disease, since ceramide has been proposed to suppress p38 activation. Three Gaucher’s disease mouse models were employed, and p38 was found to be activated in lung and liver tissues of all Gaucher’s disease mice. Most interestingly, neuronopathic Gaucher’s disease type mice, but not non-neuronopathic ones, displayed significant activation of p38 and up-regulation of p38-inducible proinflammatory cytokines in brain tissues. In addition, all type of Gaucher’s disease mice also showed increases in serum IL-6. As cellular signalling is believed to represent an in vivo inflammatory phenotype in Gaucher’s disease, activation of p38 and possibly its-associated formation of proinflammatory cytokines were assessed in fibroblasts established from neuronopathic Gaucher’s disease mice. In mouse Gaucher’s disease cells, p38 activation and IL-6 formation by TNF-α treatment were enhanced as compared to those of wild type. Furthermore, human fibroblasts from Gaucher’s disease patients also displayed increases in p38 activation and IL-6 formation as comparison to healthy counterpart. These results raise the potential that proinflammatory responses such as p38 activation and IL-6 formation are augmented in Gaucher’s disease.     

Network Analysis of a Comprehensive Knowledge Repository Reveals a Dual Role for Ceramide in Alzheimer’s Disease

Alzheimer’s disease (AD) is the most common cause of senile dementia. Many inflammatory factors such as amyloid-β and pro-inflammatory cytokines are known to contribute to the inflammatory response in the AD brain. Sphingolipids are widely known to have roles in the pathogenesis of inflammatory diseases, where the precise roles for sphingolipids in inflammation-associated pathogenesis of AD are not well understood. Here we performed a network analysis to clarify the importance of sphingolipids and to model relationships among inflammatory factors and sphingolipids in AD. In this study, we have updated sphingolipid signaling and metabolic cascades in a map of AD signaling networks that we named “AlzPathway,” a comprehensive knowledge repository of signaling pathways in AD. Our network analysis of the updated AlzPathway indicates that the pathways related to ceramide are one of the primary pathways and that ceramide is one of the important players in the pathogenesis of AD. The results of our analysis suggest the following two prospects about inflammation in AD: (1) ceramide could play important roles in both inflammatory and anti-inflammatory pathways of AD, and (2) several factors such as Sphingomyelinase and Siglec-11 may be associated with ceramide related inflammation and anti-inflammation pathways in AD. In this study, network analysis of comprehensive knowledge repository reveals a dual role for ceramide in AD. This result provides a clue to clarify sphingolipids related inflammatory and anti-inflammatory pathways in AD.     

Characterization of estrogen receptor in estrogen-dependent transplantable rat pituitary tumor MtT/F84

Properties of nuclear and cytosolic estrogen receptors (ERs) were examined in a new transplantable rat pituitary tumor designated as MtT/F84, of which growth is stimulated by estrogen. The optimal incubation conditions of both nuclear and cytosolic exchange were found to be at 37 degrees C for 15 min and at 25 degrees C for 2 hr, respectively. Molybdate increased a specific binding of estradiol (E2) as determined by [3H]E2-binding assay. Sucrose density gradient analyses of crude cytosol revealed specific peaks of radioactivity in both 4-5S and 8-10S areas. However, only a single 5S peak was present in 0.4M KCl-extractable nuclear ER. Molybdate also enhanced the stability of cytosolic 8-10S receptor in density gradient sedimentation behavior. Scatchard plot analysis for nuclear ER yielded a single class of binding sites with a dissociation constant (Kd) of 0.317 nM and the maximum number of binding sites (NBSmax) of 25.4 fmol/mg protein. Saturation analysis of [3H]estrogen binding to cytosolic ER also yielded a straight line with a Kd of 0.146 nM and NBSmax of 58.5 fmol/mg protein. The effect of E2 administration on the intracellular distribution of ER was also examined. A marked disappearance in the ER binding in cytosol with a concomitant increase in binding in nuclear fraction was found after the administration of the unlabeled E2 in vivo, whereas the total number of ER did not change. Thus, it is concluded that properties of ER in the MtT/F84 were very similar to those in other target organs such as uterus and pituitary gland.     

Methane emission from paddy soils as affected by wheat straw returning mode

To study influence of wheat straw returning mode on CH₄ emission from paddy soils, a field experiment was conducted at Jurong, Jiangsu Province, China in 2006. Five treatments, no wheat straw applied (CK), wheat straw evenly incorporated into the topsoil (WI), wheat straw buried in ditches (WD), wheat straw strip-mulched onto the field surface (WM) and wheat straw burned in-situ (WB), were laid out in a randomized block design. Results showed that seasonal CH₄ emissions ranged from 6.9 to 28.1 g CH₄ m^?2. Wheat straw incorporation significantly increased CH₄ emission. No significant difference was observed between Treatments WI and WD in total CH₄ emission. Compared with Treatment WI, Treatment WM reduced total CH₄ emission by 32% and Treatment WB by 42%. Treatment WM was about 27% higher than Treatment CK in grain yield. Based on the findings, the best management of wheat straw prior to rice cultivation is strip-mulching wheat straw onto the field surface, which largely reduced CH₄ emission from rice fields with no decrease in rice yield.