CD44 stimulation down-regulates Fas expression and Fas-mediated apoptosis of lung cancer cells

Cytotoxic T lymphocytes (CTL) play a major role in the rejection of tumor cells, but tumor rejection does not always occur in vivo, indicating that defects in anti-tumor immune responses may be common. We here document a novel function for CD44--using lung cancer cells, we showed that stimulation of CD44 reduced Fas expression and Fas-mediated apoptosis: (i) lung cancer cells expressed high levels of CD44; (ii) engagement of CD44 on the cells by a specific antibody or fragmented hyaluronan reduced Fas expression; (iii) CD44 cross-linking reduced Fas-mediated apoptosis; (iv) stimulation of CD44 on lung cancer cells decreased IFN-gamma production by autologous CTL; and (v) CD44 stimulation prevented killing of lung cancer cells by autologous CTL. Based on these findings, we postulate a new concept--that interaction of CD44 on lung cancer cells with fragments of extracellular hyaluronan present in the surrounding extracellular matrix reduces Fas expression as well as Fas-mediated apoptosis of cancer cells. This leads to reduced susceptibility of the cells to CTL-mediated cytotoxicity through the Fas-Fas ligand pathway.     

Histochemical studies on glycosaminoglycans in Bruch's membrane of postnatal rat eyes

Localization of glycosaminoglycans (GAG) in Bruch's membrane of postnatal rat eyeballs was examined histochemically. Fixed eyeballs from postnatal rats (ages 5 days and 8 weeks) were routinely processed and embedded in paraffin wax or Quetol 651 resin. Paraffin-embedded tissue sections were stained with hematoxylin and eosin or sensitized high iron diamine procedure in combination with selective methods such as GAG-degrading enzyme digestions and/or a chemical modification, and examined by light microscopy. Quetol 651-embedded ultrathin sections were stained with heavy metals and examined by electron microscopy. In rats at postnatal day 5, Bruch's membrane contained mainly chondroitin sulfate (CS) and heparan sulfate (HS). In contrast, at 8 weeks after birth the membrane included a large amount of dermatan sulfate (DS) and HS. According to electron microscopic findings, Bruch's membrane on day 5 consisted of only 3 layers without a central elastic layer. However, at 8 weeks after birth the membrane was constructed of 5 layers. These findings suggested that the difference in GAG molecular species in the membranes at 5 days and at 8 weeks after birth could be correlated with the development and maturation of the collagenous layer in Bruch's membrane. Moreover, maturation of Bruch's membrane may contributes to the architectural stabilization of the outer portions of the photoreceptor cells.     

New algorithmic-based digital filter processing system for real-time continuous blood pressure measurement and analysis in conscious rats

A new algorithmic-based digital filter processing system for real-time continuous blood pressure (BP) measurement and analysis in freely-moving conscious rats has been developed. Real-time recognition of BP waveforms, real-time noise rejection and determination of representative waveform indexes (WIs) at indicated time points using digital filters and Smirnov's rejection test were realized with this system. Digital filters were applied for two different purposes: waveform segmentation and smoothing the calculations of representative WIs. Smirnov's rejection test was used for real-time noise rejection and yielded an accurate rejection rate of 99.99%. The result was that the digital filter processing and Smirnov's rejection test realized accurate real-time BP measurement and analysis in freely-moving conscious rats using a personal computer.     

Stereological analysis of Reinke's crystals in human Leydig cells

Summary Reinke's crystals in human Leydig cells were analyzed stereologically to assess their functional role. Testicular tissues were taken from seven older men (57–82 years old) with prostatic carcinoma and also from seven younger men (26–38 y.o.) complaining of male infertility. Sections 0.5 m thick, stained with toluidine blue or Heidenhein's iron-hematoxylin were examined by a point-counting method and with a Particle Measurement Computor System (MC). When the patients were grouped by age, the mean crystal volume, the number of crystals per cell, the volume of crystals per cell and the volume ratio of crystals to cell were significantly larger in the older age group than in the younger age group. In particular, the latter three variables correlated well with the age of subjects, with correlation coefficients of r=0.66–0.85. On the other hand, none of these variables had any correlation with the concentration of plasma testosterone. These results indicate that Reinke's crystals can be considered as degenerative products in cell life but not as facultative constituents for testosterone production.Supported in part by a grant from Medical Foundation of Ehime, Japan     

Stoichiometric salt-linkage formation of trimethylammonium glycol chitosan iodide with a carboxylic type ion exchanger

The adsorption of trimethylammonium glycol chitosan iodide (TGCI) on Dowex CCR-2 resin was investigated at different pH values and resin weights. The concentration of Na⁺ or Ca²⁺ ions, released by the ion exchange reaction with TGCI, was measured by inductively coupled plasma spectroscopy. It was found that the amount of the released ions is comparable to that of the absorbed TGCI. This indicates that the salt-linkage formation of carboxylate ions of the exchanger with ⊕N(CH₃)₃-groups in TGCI follows a stoichiometric relationship. This result is discussed in connection with the form of the polymer layer adsorbed on the solid surface.     

Carbohydrate expression profile of colorectal cancer cells is relevant to metastatic pattern and prognosis

Carbohydrate expression of cancer cells is closely related to the metastatic nature of colorectal cancer. In the present study we investigated the relevance of carbohydrate expression profiles of colorectal cancer cells in the primary lesion to metastatic distribution patterns as well as prognosis in 134 cases. Carbohydrate expression was estimated by histochemistry with 17 kinds of lectins and 3 kinds of Lewis-related monoclonal antibodies (MAbs), and correlations between the staining and clinicopathological parameters were examined. The results showed that lymphatic invasion, lymph node metastasis, and peritoneal metastasis correlated with staining with lectins that bind galactose/N-acetylgalactosamine residues (Gal/GalNAc) such as Maclura pomifera (MPA), Arachis hypogaea (PNA), Helix pomatia (HPA), and Vicia villosa (VVA). In contrast, hepatic metastasis correlated with staining with Anguilla anguilla lectin (AAA), anti-Lewis^X (LEX-2), anti-sialyl Lewis^a (NS19-9), and anti-sialyl-dimeric Lewis^X (FH-6) MAbs, all of which bind preferentially to fucosylated carbohydrate chains. The five-year survival rate of patients was related to the staining of cancers with MPA, HPA, FH-6 or NS19-9, and MPA- and FH-6 staining were independent prognostic factors. We conclude that carbohydrate expression profiles of cancer cells are relevant to the route of tumor cell dissemination, metastatic pattern as well as prognosis of colorectal cancer.     

Twenty-six-Week carcinogenicity study of chloroform in CB6F1 rasH2-transgenic mice

The carcinogenic potential of chloroform was evaluated in a short-term carcinogenicity testing system using CB6F1 rasH2-Tg (rasH2-Tg) mice. Chloroform was administered to rasH2-Tg males at doses of 28, 90, or 140 mg/kg and rasH2-Tg females at 24, 90, or 240 mg/kg by oral gavage for 26 weeks. Wild-type (non-Tg) male and female mice received doses of 140 mg/kg and 240 mg/kg, respectively. N-methyl-N-nitrosourea was administered to rasH2-Tg mice by single intraperitoneal injection (75 mg/kg) as a positive control. In both the rasH2-Tg and non-Tg mice, there was no significant increase in the incidence of neoplastic lesions by chloroform treatment. The incidence of hepatocellular foci in the rasH2- and non-Tg females receiving 240 mg/kg was increased. Forestomach tumors and malignant tumors occurred in most of the rasH2-mice in the positive control group. Swelling or vacuolation of hepatocytes, a toxic change induced by chloroform, occurred in both the rasH2-Tg and non-Tg mice. It is concluded that chloroform, a putative human noncarcinogen, did not show evidence of carcinogenic potential in the present study using rasH2-Tg mice. This study suggests that the rasH2-Tg mouse model may not be appropriate for detecting nongenotoxic carcinogens. However, the sensitivity of rasH2-Tg mice to nongenotoxic carcinogens should be assessed with consideration of the results from the other ILSI-HESI project studies.     

The corrosion resistance of pure titanium in organic acids

The purpose of this study was to assess the corrosive properties of titanium at various pH values. Cast pure titanium specimens were immersed in 128 mmol/l of lactic and formic acids at pH 1.0-8.5 for 3 weeks at 37 degrees C. The solubility, color, weight and chemical binding state of specimens were observed. Titanium dissolved in all lactic acid. The amount of dissolved titanium tended to decrease with a higher pH. In formic acid, the amount of dissolved titanium at pH 1.0 was larger than that in lactic acid at the same pH, but less than the detectable limit at pH 4.0 or higher. Significant discoloration was macroscopically observed only in formic acid at pH 2.5 and 4.0. The weight of the titanium samples immersed in lactic acid all decreased, but it was not affected by pH. In formic acid, the weight decreased at pH 1.0 and increased at pH 2.5-5.5. Thickening of the TiO2 corresponding to that showing discoloration was observed in the superficial oxide film of the titanium samples. Our results show that the corrosive properties of titanium are markedly dependent on pH in formic acid, and relatively less dependent on pH in lactic acid in which titanium is dissolvable at pH 1.0-8.5.     

A histological evaluation for guided bone regeneration induced by a collagenous membrane

This study was designed to evaluate the histological changes during ossification and cellular events including osteogenic differentiation responding to collagenous bioresorbable membranes utilized for GBR. Standardized artificial bony defects were prepared at rat maxillae, and covered with a collagenous bioresorbable membrane. These animals were sacrificed at 1, 2, 3 and 4 weeks after the GBR-operation. The paraffin sections were subject to tartrate resistant acid phosphatase (TRAP) enzyme histochemistry and immunohistochemistry for alkaline phosphatase (ALP), osteopontin (OP) and osteocalcin (OC). In the first week of the experimental group, woven bone with ALP-positive osteoblasts occupied the lower half of the cavity. The collagenous membrane included numerous ALP-negative cells and OP-immunoreactive extracellular matrices. At 2 weeks, the ALP-, OP- and OC-immunoreactivity came to be recognizable in the region of collagenous membrane. Since ALP-negative soft tissue separated the collagenous membrane and the new bone originating from the cavity bottom, the collagenous membrane appeared to induce osteogenesis in situ. At 3 weeks, numerous collagen fibers of the membrane were embedded in the adjacent bone matrix. At 4 weeks, the membrane-associated and the cavity-derived bones had completely integrated, showing the same height of the periosteal ridge as the surrounding alveolar bones. The collagen fibers of a GBR-membrane appear to participate in osteogenic differentiation.     

Immunohistochemical analysis of MCT1, MCT2 and MCT4 expression in rat plantaris muscle

All three forms of recombinant low voltage-activated T-type Ca²⁺ channels (Ca_v3.1, Ca_v3.2 and Ca_v3.3) exhibit a small, though clearly evident, window T-type Ca²⁺ current ( I _Twindow) which is also present in native channels from different neuronal types. In thalamocortical (TC) and nucleus reticularis thalami (NRT) neurones, and possibly in neocortical cells, an I _Twindow-mediated bistability is the key cellular mechanism underlying the expression of the slow (< 1 Hz) sleep oscillation, one of the fundamental EEG rhythms of non-REM sleep. As the I _Twindow-mediated bistability may also represent one of the cellular mechanisms underlying the expression of high frequency burst firing in awake conditions, I _Twindow is of critical importance in neuronal population dynamics associated with different behavioural states.