Production of the first offspring from oocytes derived from fresh and cryopreserved pre-antral follicles of adult mice

Although mammalian ovaries contain hundreds of thousands of pre-antral follicles, fewer than 1% of these reach maturity and ovulation. Obtaining immature eggs from the pre-antral follicles of ovarian tissue could increase the possibility of preserving fertility in women undergoing anti-cancer treatment, and in women who wish to delay pregnancy and child raising until they are older. This study reports the birth of 10 healthy mouse pups derived from oocytes obtained from pre-antral follicles after adult ovary tissue cryopreservation and allotransplantation. High in-vitro maturation (55.1%), fertilization (76.3%) and cleavage (98.3%) rates were achieved using these oocytes, and there was no significant difference between the vitrified and control samples except in maturation rate (55.1 versus 72.8%, P < 0.05). After an ultra-rapid vitrification procedure, the warmed tissue fragments were transplanted beneath the kidney capsule of severe combined immunodeficient mice for onward in-vivo culture. Within 10 days of culture, 138 full size oocytes developed from the 456 transplanted pre-antral follicles. In-vivo growth of follicles was followed by in-vitro oocyte maturation, in-vitro fertilization and subsequent embryo transfer, leading to the birth of 10 healthy pups. These results may lead to increasing the possibility of preserving fertility by cryopreservation of ovarian tissue.     

Light and electron microscopic and autoradiographic studies onN-methyl-N-amylnitrosamine-induced rat esophageal carcinogenesis

The purpose of this study was to investigate the histogenesis of experimental tumors in the rat esophagus. Thirty rats received 0.0015% N-methyl-N-amylnitrosamine (MNAN) in the drinking water for 12 weeks. Another 30 rats received tap water. All rats then received tap water until sacrifice. Rats from each group were sacrificed immediately after MNAN administration, four weeks after, and eight weeks after. One hour before sacrifice, [³H]TdR was injected by tail vein to label proliferating cells. The entire esophagus and stomach were removed and processed for light and electron microscopy and autoradiography. The overall frequency of esophageal tumors after MNAN was 83% and did not differ significantly among the three experimental groups. Tumors were primarily papillomas and squamous cell carcinomas and occurred with equal frequency in the upper, middle, and lower thirds of the esophagus. No tumors were found in the squamous-lined forestomach. Electron microscopy revealed abundant tonofilaments, free ribosomes, and mitochondria accompanied by vacuoles. By autoradiography, esophageal epithelial proliferation was markedly stimulated in nontumorous mucosa from all three experimental groups. We conclude that MNAN ingestion for 12 weeks reliably produces papillomas and squamous cell carcinomas throughout the rat esophagus, but not in the squamouslined forestomach, and that MNAN stimulated marked epithelial proliferation which is accompanied by thickening of the epithelium in nontumorus esophageal mucosa.     

Effect of long-term sucralfate ingestion on antral and fundic epithelial proliferation in the rat

Sucralfate accelerates the healing of chronic gastric ulcers, but its mechanism is not well understood. We studied the effect of long-term administration of sucralfate on gastric epithelial proliferation in the rat by means of tritiated thymidine autoradiography. Rats were treated perorally with 500 mg/kg sucralfate once a day. After 28 days, rats were injected with tritiated thymidine 1µCi/g body weight and sacrificed 1 hr later. Autoradiographs from antral and fundic mucosae were prepared and a number of proliferative measurements were made. Long-term sucralfate administration produced an increase in tritiated thymidine labeling of epithelial cells and expansion of the proliferative zone in antral mucosa. These results indicate that long-term sucralfate ingestion stimulates gastric antral epithelial proliferation in the rat. In light of the fact that chronic gastric ulcers are usually located in the antral region in humans, this enhanced epithelial proliferation may contribute to the beneficial effect of sucralfate in accelerating the healing of gastric ulcers.     

Virulent influenza A viruses induce apoptosis in chickens

Virulent avian influenza A viruses produce lethal disease in chickens. Since cell death can be caused by either necrosis or apoptosis, we investigated the types of cell death that occur in natural hosts, chickens, infected with virulent avian viruses. Using biochemical methods, we demonstrate that virulent avian influenza viruses induce apoptosis of vascular endothelial cells in liver, kidney, and brain. Viral antigens were also detected in these organs, suggesting that viral replication induces apoptosis in infected chickens. These results indicate that apoptosis does occur in virulent avian influenza virus infection in a natural host, and may contribute to the lethality of the virus.     

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.     

Correlation between microstructure of Ag-Pd-Au-Cu alloy and changes in shape on aging

An investigation has been carried out to study changes in shape on aging in plastic deformed Ag-Pd-Au-Cu alloys. The changes in shape were measured in order to establish a relationship to the aging heat treatments. Their microstructure was observed in order to clarify this phenomenon at the same time. They were also investigated quantitatively using a feature analysis system. The changes in shape were interpreted as the shrinkage in volume resulting from the formation of the ordered phase. They were smaller at aging temperatures below 673 K. The change in microstructure was different at aging temperature between 573 and 773 K. These phenomena were due to the following: First, nodules which nucleated at the grain boundaries would have grown into the grains well before the formation of the ordered phase, and second, the shrinkage in volume would have been of a different kind that the ordered phase. Therefore aging treatments should be carried out at low temperature in order to minimize the changes in shape. Also, nodular growth should be inhibited in order to maximize the hardening in Ag-rich alloys.     

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.