Particle-like and fluid-like settling of a stratified suspension

The gravitational settling of inhomogeneously suspended particles in a fluid has been investigated. Of particular interest is whether collective or individual motion of particles is dominant during their settlings, i.e., whether the particles settle as a continuous suspension or they settle individually relative to the surrounding fluid. We observed the settling of a stratified suspension which has the lower and upper concentration interfaces in a quasi-two-dimensional vessel. In some cases, the suspension behaves perfectly as a continuous fluid and the motion of the constituent particle is subject to bulk flow caused by the interfacial instability. In other cases, the particle behaves individually relative to the surrounding fluid. The existence of a concentration interface plays a significant role in these extreme behaviors of suspension. The transition from the collective to individual behaviors can be predicted quantitatively by a parameter which expresses the border resolution of the concentration interface.

Identification and characterization of the short variable region of the Japanese encephalitis virus 3' NTR

Since the 1980s, the Japanese encephalitis virus (JEV) variants with slightly short variable regions (VR) of the 3' non-translated region (NTR) have been found; however, the implications of these short VR remain unclear. We recently identified two novel types of short VR (5 and 9 nt shorter than that of major group of genotype I JEV strains) of genotype I JEV isolates. To elucidate the impact of these short VR on the replication and virulence of JEV, we generated five recombinant JEV viruses: M41-d5 and M41-d9 have deletions in the VR that correspond to those observed in some recent JEV isolates, M41-d5d9 has both the 5- and 9-nt deletions in the VR, M41-d27 has a large deletion that encompasses both the 5- and 9-nt deletion regions, and M41-a13 has a 13-nt sequence insertion of the genotype III JEV strain Beijing-1 into the parent genotype I JEV strain Mie/41/2002 genome. The recombinant viruses and the parent virus, except for the M41-d27 mutant, showed similar growth properties in mammalian and mosquito cell lines. Mouse challenge experiments indicated that no significant differences among the recombinant viruses M41-d5d9, M41-d27, M41-a13, and the parent virus. Our results suggest that the short VR in JEV 3' NTR do not affect its growth in vitro or its pathogenicity in mice.

Role of transcription factors in small intestinal ischemia-reperfusion injury and tolerance induced by ischemic preconditioning

BACKGROUND

Small intestinal ischemia-reperfusion (I/R) injury, a clinically important condition, induces severe organ damage. Ischemic preconditioning (IPC) produces tolerance to long-term I/R by inducing a short-term I/R. Herein, we have examined the reduction in the extent of injury by IPC.

METHODS

Small intestinal I/R injury was induced in rats by clamping the superior mesenteric artery (SMA) for 30 minutes followed by reperfusion for various 30 minutes. The IPC + I/R group underwent a short-term I/R (IPC) prior to long-term I/R. Nuclear factor-κB (NF-κB) activity was analyzed by an electrophoretic mobility shift assay and cytokine mRNA levels, by reverse transcription-polymerase chain reaction. Apoptosis-related genes were analyzed by Western blotting and immunohistochemistry, and apoptotic cells, by TUNEL staining.

RESULTS

The animals were subjected to 30 minutes of ischemia followed by 30 minutes of reperfusion. NF-κB activity increased in the I/R group and decreased in the IPC + I/R group. The IPC + I/R group showed decreased cytokine in mRNA levels. Expression of the proapoptotic gene caspase-3 was increased in the I/R and decreased in the IPC + I/R group. Expression of the antiapoptotic gene Bcl-xL was increased in the IPC + I/R group. The number of apoptotic cells was increased in the I/R and decreased in the IPC + I/R group.

CONCLUSION

Small intestinal I/R injury was reduced by IPC produced by clamping the SMA; thus, IPC may have potential clinical applications in the future.

An adult norovirus-related encephalitis/encephalopathy with mild clinical manifestation

Norovirus is an emerging pathogen that causes gastroenteritis outbreaks. Here, we reported an adult female case of norovirus-related encephalitis/encephalopathy (NvREE) with abnormal behaviour, apathy, motor aphasia, bradykinesia and gait disturbance. We treated the patient with intravenous methyl-prednisolone pulse therapy and she recovered quickly. There were slight abnormal signals in the cortex of the opercular part and insula on the MRI fluid-attenuated inversion-recovery (FLAIR) image, generalised slow wave as a background activity in her EEG and cerebrospinal fluid pleocytosis, which restored soon after her recovery. We successfully detected the norovirus genome in stool samples from all seven family members. This is a first case report of an adult NvREE with detection of pathogenic evidence. There could be more cases of NvREE with mild neuropsychiatric symptoms, considering the increasing outbreaks each year.

A novel nonsecosteroidal VDR agonist (CH5036249) exhibits efficacy in a spontaneous benign prostatic hyperplasia beagle model

To date, there have been no reports showing the efficacy of nonsecosteroidal vitamin D receptor (VDR) agonists in a benign prostatic hyperplasia (BPH) animal model. To examine the efficacy of CH5036249, a novel nonsecosteroidal VDR agonist, we orally administered the compound at 0.03 microg/kg to a beagle model with spontaneous BPH. Prostate volume was checked by rectal ultrasonic probe periodically during 11 months of administration and the prostate tissues histologically examined. CH5036249 inhibited prostate growth in two out of three dogs compared with vehicle-treated dogs. In the prostate specimens, substantial atrophy of the epithelium was observed in all dogs administered CH5036249. At the dose given, serum calcium levels slightly increased in the CH5036249-treated dogs but stayed within a normal range. We next examined the cell growth inhibition of CH5036249 using human prostate stromal cells and found the cell growth inhibitory activity of CH5036249 to be comparable to that of 1alpha,25(OH)2D3. The bioavailability from oral administration in rats was 95.1% with a t1/2 of 17.6 h. Both micro-AMES and micronucleus tests were negative. Although the results are still preliminary, we consider the novel nonsecosteroidal VDR agonist CH5036249 to be a possible new drug candidate for the treatment of BPH in humans.

Antibodies to bovine serum albumin in human sera: problems and solutions with casein-based ELISA in the detection of natural Japanese encephalitis virus infections

An ELISA system for measuring antibodies to nonstructural protein 1 (NS1) of Japanese encephalitis virus has already been established. This system uses an ELISA diluent containing casein, instead of bovine serum albumin (BSA). During a survey, we found that 21 (21%) of 102 children aged 1-5 years, who had no history of Japanese encephalitis vaccination and were without detectable neutralizing antibodies, showed positive results with this ELISA system. Western blotting analysis showed that sera from 19 (91%) of these 21 subjects had antibodies to BSA, but not NS1. These sera reacted with BSA antigen remaining in immunoaffinity-purified NS1 antigen. One solution to this problem was to reduce the BSA level to < or =1% of the NS1 amount. Another was to use a control well sensitized with BSA with the same amount as that contained in the NS1 antigen preparation.

[Vacuum-assisted closure therapy for the treatment of sternal wound infection after cardiac surgery]

Sternal wound infection is still one of the critical and challenging complications after cardiac surgery. Vacuum-assisted closure (VAC) therapy is a unique and simple system that helps promote wound healing. We report 3 cases with the sternal wound infection after cardiac surgery, in which VAC therapy was applied between January, 2005 and April, 2007. Two of them had good response to VAC therapy and had their wound healed after 3 and 5 weeks, respectively. However, the remaining case, in which bilateral internal thoracic artery had been taken down for coronary artery bypass grafting (CABG) and osteomyelitis of the sternum was not well controlled, did not respond to VAC therapy. Our results suggested that VAC might facilitate wound healing of the patients with sternal wound infection only after abscess was drained and opened, while it might not be useful for the patents with osteomyelitis.

Vacuum-assisted closure for bilateral severe ischemic foot after revascularization: a case report

Vacuum-assisted closure (VAC) therapy is a unique system that helps promote wound healing. We report a case of severe ischemic foot in which VAC therapy markedly improved wound healing. A 73-year-old man underwent left axillopopliteal bypass and left 3rd, 4th , and 5th digital amputations for gangrene. Although his amputation stumps were complicated with methicillin-resistant Staphylococcus aureus (MRSA) infection, the stumps were successfully healed by VAC. He also had gangrene in his right 1st toe, which could not healed by VAC alone, and we performed right femoropopliteal bypass and right 1st digital amputation. The stump with MRSA infection was also successfully healed by VAC. Histopathologic examination revealed a lot of microvessels in the increased granulation tissue.

Surveillance of pathogens in outpatients with gastroenteritis and characterization of sapovirus strains between 2002 and 2007 in Kumamoto Prefecture, Japan

Infectious acute gastroenteritis is an important public health problem worldwide. A total of 639 stool specimens were tested for the presence of diarrhea pathogens. The specimens were from outpatients with acute gastroenteritis who consulted the pediatric clinic in Kumamoto Prefecture, Japan, from June 2002 to December 2007. Of these, 421 (65.9%) were positive for diarrhea pathogens. Among them were norovirus (NoV) in 260 (61.8%), sapovirus (SaV) in 81 (19.2%), rotavirus in 49 (11.6%), adenovirus in 19 (4.5%), enterovirus in 13 (3.1%), astrovirus in 9 (2.1%), kobuvirus in 1 (0.2%), and bacterial pathogens in 11 (2.6%). Mixed infection (co-infection of viruses) was found in 22 (5.2%) of the 421 pathogen-positive stool samples. NoV was the most prevalent pathogen throughout the study period; however, the SaV detection rate was unexpectedly high and was found to be the secondary pathogen from 2005 to 2007. Genetic analysis of SaV with 81 strains demonstrated that SaV strains belonging to genogroup IV emerged in 2007, and dynamic genogroup changes occurred in a restricted geographic area. This study showed that SaV infection is not as rare as thought previously.

Downstream genes of Sox8 that would affect adult male fertility

Sertoli cells provide nutritional and physical support to germ cells during spermatogenesis. Sox8 encodes a high mobility group transcription factor closely related to Sox9 and Sox10. Sertoli cells produceSOX8 protein, and its elimination results in an age-dependent deregulation of spermatogenesis resulting in male infertility. This suggests that Sox8 is a critical regulator of Sertoli cell function for the maintenance of male fertility beyond the first wave of spermatogenesis. To better understand the roles of Sox8 in testicular development and maintenance of male fertility, we have performed a detailed analysis to explore its downstream genes. We have used mRNA expression profiling to identify affected genes in Sertoli cells in the mutant testes of 2-month-old mice. Expression profiling of the heterozygous and homozygous Sox8 mutant testes indicates alterations in several important spermatogenesis and blood-testis barrier genes, providing insight into the molecular basis of the defects in Sox8(-/-) testes beyond the first wave of spermatogenesis.