Mucin secreted by mucosal epithelial cells plays a role in the protection of the mucosal surface and also is involved in pathological processes. So far, MUC1-4, 5AC, 5B, 6-8, 11-13 and 15-17 genes coding the backbone mucin core protein have been identified in humans. Their diverse physiological distribution and pathological alterations have been reported. We have studied the expression profiles of MUC genes in the intrahepatic biliary system in developmental, normal and diseased livers using immunohistochemistry and in situ hybridization. Fetal intrahepatic bile ducts and ductal plates frequently express MUC1, while intrahepatic large bile ducts after birth express mainly MUC3 mucin. In hepatolithiasis, MUC5AC (gastric foveolar epithelial type) and MUC6 (pyloric gland type) mucins are newly expressed in surface epithelial cells and proliferated peribiliary glands, respectively, and the expression of gel-forming mucin may play a role in lithogenesis. Most biliary epithelial dysplasias and cholangiocarcinomas associated with hepatolithiasis expressed MUC5AC, suggesting that intrahepatic bile ducts express the gastric foveolar phenotype during carcinogenesis. In addition, intestinal metaplasia, intraductal papillary tumor and mucinous carcinoma, characterized by MUC2 expression, are occasionally associated with hepatolithiasis in a CDX2 homeobox gene-dependent manner. These findings may suggest the presence of intestinal metaplasia-related carcinogenesis in the intrahepatic biliary system as in the stomach.

View full abstract

The present study examined whether low-temperature (LT) could reduce experimentally-induced atrophy of the skeletal muscle in non-hibernating mammals, as judged by muscle wet-weight, cross-sectional area of muscle fibers, ratio of muscle fiber types, and number of apoptotic myofibers in the soleus muscle of rat. Hindlimb unloading (HU) was carried out for either one or two weeks (1W or 2W, respectively) at room temperature (HU-1W and HU-2W groups) or LT (10°C, HULT-1W and HULT-2W groups). Other animals were allowed to move freely at either room temperature (CON-1W and CON-2W groups) or LT (LT-1W and LT-2W groups). Total caloric intake was increased in LT rats compared with the CON, HULT and HU rats. Body weight, muscle wet-weight and cross-sectional area were significantly decreased in HU and HULT rats compared with CON and/or LT rats. Type-I fiber composition in HULT-2W was not significantly reduced compared with those of CON-2W and LT-2W, but that of HU-2W was significantly reduced compared with the other groups. A small number of caspase-3-activated myofibers appeared in HULT-2W and HU-2W, but not in CON-2W and LT-2W. Thus, our results indicate that LT retards the change in the ratio of type-I and type-II fibers, but does not prevent decreases in muscle size and mass, or apoptosis of myofibers.

View full abstract

Recent evidence has shown that certain tumors have characteristic cell populations related to tumor progression. Therefore, we investigated tumor cell populations in 7,12-dimethylbenz[a]anthracene (DMBA)-induced rat mammary tumor, an established estrogen-sensitive angiogenic tumor model. The tumors pathologically identified as invasive ductal carcinoma were immunostained using antibodies against the following various molecules: vascular endothelial growth factor (VEGF), integrins, estrogen receptor alpha (ERα), human epidermal growth factor receptor-2 (HER2), p27, and laminin, all of which are known to be related to tumor progression, proliferation and/or prognosis. The basal layer, the outermost layer of tumor lobules facing the basement membrane, was mainly VEGF and integrin (α3, α6, β1) positive. In contrast, the inner layer, the internal cell layers of the tumor lobules, was mainly ERα and HER2 positive. The p27-positive rate in the inner layer was similarly low to that in the basal layer, suggesting a similar high proliferative potency between these layers. Laminin was positive in the basement membrane surrounding the tumor lobules. These results suggest that the tumor lobules consist of at least two cell populations, the basal and inner layers, with respect to the expression of VEGF, integrins, ERα and HER2; and that these cell populations may have distinct functions in the pathophysiology of this mammary tumor.

View full abstract

Survivin is a new member of the inhibitor of apoptosis protein (IAP) family, selectively over-expressed in common human cancers but not in normal adult tissues. It is also expressed in cancer cell lines. Chemotherapeutic drugs exert adverse effects on cell survival.
This work aimed to study the effects of doxorubicin, 5-fluorouracil, cyclophosphamide, and tamoxifen on cell viability, apoptosis, and survivin expression in the human breast cancer cell line MCF-7. After 72 hours incubation, inhibition of MCF-7 growth induced by different concentrations of doxorubicin, 5-fluorouracil, cyclophosphamide, and tamoxifen was evaluated by MTT assay, while alteration of survivin expression and subcellular distribution was evaluated by immunocytochemistry. Apoptosis was detected by propidium iodide/acridine orange dyes. The cell viability was reduced in a dose-dependent pattern when incubated with the drugs. It was found that most of the MCF-7 cells expressed survivin, predominantly in the cyctoplasm. The percentages of apoptotic cells were increased with the increased concentrations of the drugs.

View full abstract

Gastric parietal cells are characterized by intracellular canaliculi with many microvilli and tubulovesicles. These membranous structures are continuous and change in volume according to gastric acid secreting or resting state. Morphological changes are induced by cytoskeletal actin. Actin filaments are anchored to the cell membrane via ezrin. This study aimed to ascertain whether morphological changes were related to the nature of ezrin molecules, which were either phosphorylated or non-phosphorylated. Rat stomach tissues were rapid-frozen followed by freeze-substitution and embedding in paraffin for light microscopy. Also, the specimens were high pressure-frozen, freeze-substituted and embedded in Epon 812 or Lowicryl K4M for electron microscopy. Sections from paraffin or Lowicryl K4M were stained with anti-H⁺·K⁺-ATPase antibodies, anti-phosphorylated or non-phosphorylated ezrin antibodies, and anti-actin antibody. The H⁺·K⁺-ATPase was distributed on the intracellular canaliculi and tubulovesicles. The intracellular canaliculi were labeled with anti-phosphorylated ezrin antibodies in fed (gastric acid secreting state) rats. These were stained weakly in starved (gastric acid resting state) rats. Anti-nonphosphorylated ezrin antibodies hardly stained these organelles in either state. A possible explanation is that the phosphorylation of ezrin molecules is related to the reciprocal membranous transformation between intracellular canaliculi and tubulovesicles.

View full abstract

Polymorphonuclear leukocytes (PMNs) infiltrating the chorioamnion is one causal agent of preterm delivery. Although the basement membrane (BM) has been proven to be a barrier against PMN migration in various tissues, there is a lack of data focusing on the relationship between PMN morphology and chorion laeve BM. Using peroxidase enzyme-cytochemistry, we morphologically studied PMN infiltration into the chorioamnion, especially the chorion laeve BM. The accumulated PMNs lay side by side just beneath the BM, while the cytoplasmic processes of some PMNs penetrated the BM. Peroxidase deposits appeared not only in the leukocyte granule but also on the phagosomes, indicating that PMNs at the site were activated. These features resembled those of activated PMNs migrating through a filter according to the gradient of chemo-attractant. The chorion laeve BM thus may be a barrier to PMN migration through the chorioamnion. Activated PMNs and BM may be involved in the pathophysiology of preterm delivery.

View full abstract