Chronic Treatment with a Water-Soluble Extract from the Culture Medium of Ganoderma lucidum

Type 2 diabetes mellitus has been known to increase systemic oxidative stress by chronic hyperglycemia and visceral obesity and aggravate cerebral ischemic injury. On the basis of our previous study regarding a water-soluble extract from the culture medium of Ganoderma lucidum mycelia (designed as MAK), which exerts antioxidative and neuroprotective effects, the present study was conducted to evaluate the preventive effects of MAK on apoptosis and necroptosis (a programmed necrosis) induced by hypoxia/ischemia (H/I) in type 2 diabetic KKAy mice. H/I was induced by a combination of unilateral common carotid artery ligation with hypoxia (8% O2 for 20 min) and subsequent reoxygenation. Pretreatment with MAK (1 g/kg, p.o.) for a week significantly reduced H/I-induced neurological deficits and brain infarction volume assessed at 24 h of reoxygenation. Histochemical analysis showed that MAK significantly suppressed superoxide production, neuronal cell death, and vacuolation in the ischemic penumbra, which was accompanied by a decrease in the numbers of TUNEL- or cleaved caspase-3-positive cells. Furthermore, MAK decreased the expression of receptor-interacting protein kinase 3 mRNA and protein, a key molecule for necroptosis. These results suggest that MAK confers resistance to apoptotic and necroptotic cell death and relieves H/I-induced cerebral ischemic injury in type 2 diabetic mice

The surveillance of colistin resistance and mobilized colistin resistance genes in multidrug-resistant Enterobacteriaceae isolated in Japan

Background: The plasmid-mediated bacterial colistin-resistant gene, mcr, is of global concern in clini-cal healthcare. However, there are few reports of surveillance for mcr in Japan. The aim of this study was to assess the prevalence of colistin resistance by identifying nine mcr genes in extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae and carbapenem-resistant Enterobacteriaceae (CRE) isolates in Japan.Methods: A total of 273 ESBL and CRE clinical isolates were collected from patients in five tertiary hospi-tals from August 2016 to March 2017. Minimum inhibitory concentration (MIC) of colistin was measured using the microdilution method. Polymerase chain reaction (PCR) was performed to detect mcr-1 to mcr-9 genes in all strains. Whole-genome sequencing (WGS) analysis was conducted for any mcr-genes identi-fied that had not been previously reported in patients from Japan.Results: The rate of colistin resistance was 7.7% in all strains, with a higher rate in the CRE strains than in the ESBL-producing strains (20.4% versus 1.1%). The mcr-5 and mcr-9 gene were detected in one ESBL-producing Escherichia coli strain (1/273, 0.37%) and three CRE strains (3/273, 1.1%), respectively. As theESBL-producing E. coli strain was the first clinical strain with mcr-5 in Japan, WGS analysis was performed for the strain. The sequence type of the mcr-5-positive strain was ST1642 and it carried two distinct plasmids, ESBL gene-carrying pN-ES-6-1, and mcr-5.1-carrying pN-ES-6-2.Conclusions: The results of this study showed that the frequency of colistin resistance and mcr-positive strains is not high in Japan. As the MIC for colistin was low in the mcr-5.1 and mcr-9 gene-positive strain, continuous monitoring of mcr genes is necessary

Relationship between Transmission Intensity and Incidence of Dengue Hemorrhagic Fever in Thailand

An infection with dengue virus may lead to dengue hemorrhagic fever (DHF), a dangerous illness. There is no approved vaccine for this most prevalent mosquito-borne virus, which infects tens of millions (or more) people annually. Therefore, health authorities have been putting an emphasis on reduction of vector mosquitoes, genus Aedes. However, a new mathematical hypothesis predicted, quite paradoxically, that reducing Aedes mosquitoes in highly endemic countries may “increase” the incidence of DHF. To test this hypothesis based upon actual data, we compared DHF incidence collected from each of 1,000 districts in Thailand to data of Aedes abundance, which was obtained by surveying one million households. This analysis showed that reducing Aedes abundance from the highest level in Thailand to a moderate level would increase the incidence by more than 40%. In addition, we developed computer simulation software based upon the above hypothesis. The simulation predicted that epidemiological studies should be continued for a very long duration, preferably over a decade, to clearly detect such a paradoxical relationship between Aedes abundance and incidence of DHF. Such long-term studies are necessary, especially because tremendous efforts and resources have been (and perhaps will be) spent on combating Aedes

Time-dependent behaviors of methane-hydrate bearing sediments in triaxial compression test

Natural gas hydrate, existing in marine sediments worldwide and in permafrost regions, is anticipated to be a promising energy resource. It is essential to consider the mechanical properties, including their time dependence, of a gas hydrate reservoir to simulate the geomechanical response to gas extraction from a reservoir. Recently it has been revealed that gas-hydrate-bearing sediments have rocklike mechanical characteristics due to the cementation effect of the hydrate between soil particles. To obtain information about the time dependence of gas-hydrate-bearing sediments, experimental methods for drained triaxial compression tests including a procedure for the preparation of artificial methane-hydrate-bearing sediment specimens have been established. Using these methods, constant-strain-rate tests and creep tests on artificial methane-hydrate-bearing sediment specimens have been conducted. In this report, the methods and results of the tests are presented, and the time-dependent behaviors of methane-hydrate-bearing sediment are discussed. On the basis of the results, the strain-rate dependence of the peak strength was examined, and it was found that the time dependence of the artificial methane-hydrate-bearing sediment is as strong as that of frozen sand and stronger than that of many other geological materials. It was also found that the creep deformation of methane-hydrate-bearing sediment is much larger than that of water-saturated sand without the hydrate. The experimental data presented in this report are expected to be used to obtain a full understanding of the deformation mechanism of methane-hydrate-bearing sediments and to formulate a constitutive equation for methane-hydrate-bearing sediments in future studies

Effects of Methane Hydrate Saturation and Confining Pressure on Strain-Rate Dependence of Artificial Methane-Hydrate-Bearing Sediment in Triaxial Compression Test

In this study, drained triaxial compression tests were conducted on artificial methane-hydrate-bearing sediment samples under various conditions of methane hydrate saturation and confining pressure. During the axial loading in the tests, the strain rate was alternated between 2 predetermined rates that were recommended in an earlier work. On the basis of the results, we examined the effects of methane hydrate saturation and confining pressure on the strain-rate dependence of triaxial compressive strength

Effects of Methane Hydrate Saturation and Confining Pressure on Strain-Rate Dependence of Artificial Methane-Hydrate-Bearing Sediment in Triaxial Compression Test

In this study, drained triaxial compression tests were conducted on artificial methane-hydrate-bearing sediment samples under various conditions of methane hydrate saturation and confining pressure. During the axial loading in the tests, the strain rate was alternated between 2 predetermined rates that were recommended in an earlier work. On the basis of the results, we examined the effects of methane hydrate saturation and confining pressure on the strain-rate dependence of triaxial compressive strength