Blood vascular architecture of the palatine tonsil in the musk shrew (Suncus murinus): scanning electron microscopic study of corrosion casts

The musk shrew, Suncus murinus, is one of the primitive mammals and has a pair of palatine tonsils. In the present study, we investigated the blood microvascular architecture of the tonsil in this animal by scanning electron microscopy of corrosion casts. The paranodular arterioles entered the lymph nodule to form a coarse capillary plexus within the nodule. Some of the arterioles reached the dome region to give rise to a fine meshwork of dome subepithelial capillaries. This dome subepithelial capillary network did not show any hairpin or switch-back patterns, as seen in human and rabbit tonsils. Both of the nodular and dome capillaries were drained into the postcapillary venules in the periphery of the nodular or the paranodular region. On the surface of these cast venules, oval-shaped indentations were seen corresponding to the luminal surface of the high endothelial venules. These venules were collected into the large vein at the bottom of the tonsil. The blood vascular architecture of the musk shrew tonsil is basically the same as those of other mucosa-associated lymphoid tissues in mammals.     

Dual functions of Runx proteins for reactivating CD8 and silencing CD4 at the commitment process into CD8 thymocytes

To understand how CD8 expression is regulated during the transition process from CD4+8+ (CD4 and CD8 double positive, DP) to CD4-8+ (CD8 single positive, CD8SP) cells in the thymus, the involvement of Runx proteins in the alteration of chromatin configuration was investigated. Using the chromatin immunoprecipitation assay, we first demonstrated that Runx proteins bind to the stage-specific CD8 enhancer, as well as the CD4 silencer, in CD8SP thymocytes. Among Runx family members, Runx3 expression was initiated in DP thymocytes receiving a positive selection signal and increased in concert with differentiation to the CD8SP stage. Furthermore, reactivation of the CD8 gene, as well as CD4 silencing, was suppressed in positively selected thymocytes of Runx dominant-negative transgenic mice. These results suggest that Runx proteins, especially Runx3, are involved in lineage specification of CD8 T cells and provide important information for understanding the mechanism for the mutually exclusive expression of coreceptors in mature thymocytes.     

Acute Low-Intensity Treadmill Running Upregulates the Expression of Intestinal Glucose Transporters via GLP-2 in Mice

The effects of exercise on nutrient digestion and absorption in the intestinal tract are not well understood. A few studies have reported that exercise training increases the expression of molecules involved in carbohydrate digestion and absorption. Exercise was also shown to increase the blood concentration of glucagon-like peptide-2 (GLP-2), which regulates carbohydrate digestion and absorption in the small intestine. Therefore, we investigated the effects of exercise on the expression of molecules involved in intestinal digestion and absorption, including GLP-2. Six-week-old male mice were divided into a sedentary (SED) and low-intensity exercise (LEx) group. LEx mice were required to run on a treadmill (12.5 m/min, 1 h), whereas SED mice rested. All mice were euthanized 1 h after exercise or rest, and plasma, jejunum, ileum, and colon samples were collected, followed by analysis via IHC, EIA, and immunoblotting. The levels of plasma GLP-2 and the jejunum expression of the GLP-2 receptor, sucrase-isomaltase (SI), and glucose transporter 2 (GLUT2) were higher in LEx mice. Thus, we showed that acute low-intensity exercise affects the expression of molecules involved in intestinal carbohydrate digestion and absorption via GLP-2. Our results suggest that exercise might be beneficial for small intestine function in individuals with intestinal frailty.     

Seven-year survivor with malignant melanoma of the anus without radical surgery

We report a case of a long-term survivor with malignant melanoma of the anus who did not undergo radical surgery. A 71-year-old woman who presented with anal bleeding and anal tumor underwent an excisional biopsy in September 1985. The biopsy specimen was a lobulated, polypoid, pigmented mass 2 cm in diameter, that had been located on the anterior wall of the anus. A satellite nodule 7 mm in diameter was found on the left wall of the anus at the level of the dentate line. Both tumors were histologically diagnosed as malignant melanoma. The primary tumor was 6 mm thick. Melanoma cells were present microscopically at the cut end of the rectum. Because of her history of ischemic heart disease, the patient rejected our recommendation that she undergo radical surgery, and received 10 courses of carboplatin 20 mg intramuscularly and OK-432 10 K.E. (Klinische Einheit) intradermally every week. A single, pigmented metastatic inguinal lymph node developed and was excised in June 1987. A recurrent tumor was detected in the rectum in October 1992, so again we recommended radical surgery. The patient rejected radical surgery again, and received 12 courses of carboplatin 10 mg intramuscularly every 2 weeks. She died of disease at home in July 1993 after surviving for 7 years and 10 months. An autopsy was not performed. This case shows that local excision of the primary lesion may be appropriate to preserve the quality of life of patients with early-stage malignant melanoma of the anus.     

Gene Expression Profile Provides Novel Insights of Fasting-Refeeding Response in Zebrafish Skeletal Muscle

Recently, fasting has been spotlighted from a healthcare perspective. However, the de-tailed biological mechanisms and significance by which the effects of fasting confer health benefits are not yet clear. Due to certain advantages of the zebrafish as a vertebrate model, it is widely utilized in biological studies. However, the biological responses to nutrient metabolism within zebrafish skeletal muscles have not yet been amply reported. Therefore, we aimed to reveal a gene expression profile in zebrafish skeletal muscles in response to fasting-refeeding. Accordingly, mRNA-sequencing and bioinformatics analysis were performed to examine comprehensive gene expression changes in skeletal muscle tissues during fasting-refeeding. Our results produced a novel set of nutrition-related genes under a fasting-refeeding protocol. Moreover, we found that five genes were dramatically upregulated in each fasting (for 24 h) and refeeding (after 3 h), exhibiting a rapid response to the provided conditional changes. The assessment of the gene length revealed that the gene set whose expression was elevated only after 3 h of refeeding had a shorter length, suggesting that nutrition-related gene function is associated with gene length. Taken together, our results from the bioinformatics analyses provide new insights into biological mechanisms induced by fasting-refeeding conditions within zebrafish skeletal muscle.     

Molecular investigation of pathogenic factors of suspected-diarrheogenic Escherichia coli isolates from patients feces

One hundred fifty-one O serotypable Escherichia coli strains which were assumed diarrheogenic E. coli among 2,240 strains of E. coli isolated from the in- and outpatients stools with or without gastrointestinal symptoms at Kyorin University Hospital from February 1994 to September 1996 were examined for the relationship between the possession of eight pathogenic factor-related genes and gastrointestinal symptoms of the patients using the polymerase chain reaction (PCR) for these strains. The rate of possession of pathogenic factor-related genes in the E. coli examined was 20.5% (31 strains) and gastrointestinal symptoms were found in all the patients with these strains except one. In the patients without gastrointestinal symptoms, E. coli isolates that possesses these genes was detected in only one case during 61 cases. The respective genes detected were eaeA and astA in each 14 strains, VT1 in 6, VT2 in 5, ST1b in 4, aggR in 3 and LT in 2, ST1a and invE gene was not detected. In particular, the O157 strains were found in 55.6% (5/9 strains) for these genes, and individual strains had VT1, VT2, eaeA and astA genes simultaneously. In contrast, none of these related genes was found in 9 strains of enteroinvasive serotype but enteropathogenic E. coli-related genes were found in 3 strains. The rate of possession of the genes related to enterotoxigenic E. coli, O159 which was most frequently isolated was low as 2.3% (1/43 strains, astA gene) and there were strains showing low correlation to the state of possession of the genes with the O serotype. Since the prevalence of the gastrointestinal symptoms is clearly high for the case which possesses the strain of which the pathogenic factor-related gene was detected, it was suggested that detection of pathogenic factor-related genes in E. coli isolates from feces using the PCR could be an effective means to decide whether the bacteria concerned was a causal bacteria or not in clinical practice.