Correspondence between food consistency and suprahyoid muscle activity, tongue pressure, and bolus transit times during the oropharyngeal phase of swallowing.

This study aimed to evaluate the effects of food texture and viscosity on the swallowing function by measuring tongue pressure and performing a videofluorographic (VF) examination. Eleven normal adults were recruited for this study. Test foods with different consistencies and liquid contents, i.e., a half-solid nutrient made of 0.8 and 1.5% agar powder, syrup, and a liquid containing 40 wt/vol% barium sulfate, were swallowed, and the anterior (AT) and posterior tongue pressures (PT) and electromyographic (EMG) activity of the suprahyoid muscles were recorded, together with VF images. The timing of each event obtained from EMG, tongue pressure, and VF recordings was measured and then compared. We found that the AT and PT activity patterns were similar and showed a single peak. The peak, area, and time duration of all of the variables for AT and PT and EMG burst increased with increasing hardness of the bolus. The onset of the EMG burst always preceded those of the AT and PT activities, while there were no significant differences in peak and offset times among EMG burst, AT, and PT. Total swallowing time and oral ejection time were significantly longer during the swallowing of 1.5% agar than any other boluses, while pharyngeal transit time and clearance time were significantly longer during the swallowing of syrup, which was as hard as the liquid, but showed a higher viscosity than the liquid. The results suggested that the major effects of food hardness were to delay oral ejection time, which strongly delays total swallowing time. In addition, pharyngeal bolus transit is not dependent on the hardness of food but on its viscosity.     

Lectin histochemistry in rat thyroid tumours

The thyroid tumours and background goiterous and adenomatous lesions induced in rats with diisopropanolnitrosamine (DIPN) plus methylthiouracil (MTU), and regenerative thyroid tissues after wounding were studied by lectin histochemistry. Ten weeks after cessation of the carcinogen treatments, carcinomas invading the surrounding tissues and blood vessels (13/20) and papillary micronodules (11/20) were formed in the thyroid tissues. In general, the carcinoma lesion was solitary, and the papillary micronodules were multiple in a single thyroid gland. Among the lectins tested, Maclura pomifera (MPA) and Solanum tuberosum (STA) showed specific binding with both carcinoma and papillary micronodule lesions, but not with the background goiterous and adenomatous lesions and regenerative thyroid tissues. The former both lesions showed higher labelling indices with BUdR or 3H-thymidine and poorer thyroglobulin accumulation than the latters, thereby indicating their enhanced proliferative capability and depressed potency of cyto-differentiation. The common cytological and histochemical properties of carcinoma lesions and papillary micronodules allow us to regard the latter as pre-invading carcinoma lesions. The lectins MPA and STA may be, therefore, used as the specific markers of malignancy in rat thyroid carcinogenesis.     

Structure of the fluorescent nucleoside of yeast phenylalanine transfer ribonucleic acid

The structure of enzymatically isolated Y nucleoside of yeast phenylalanine tRNA was established by comparing its absorption, fluorescence, and mass spectra to that of the free base. The site of ribosylation was tentatively deduced by comparing the behavior under acid conditions of the natural nucleoside to that of synthetic Y nucleoside analogs. Our results indicate that the aglycone of the enzymatically isolated nucleoside has the same structure as the free base excised by acid treatment of phenylalanine tRNA, and that the ribose is probably attached to the N-3 position of the tricyclic nucleus.     

A second type of rat phosphoinositide-specific phospholipase C containing a src-related sequence not essential for phosphoinositide-hydrolyzing activity

A fourth type of rat phosphoinositide-specific phospholipase C (PLC IV) has been cloned for cDNA and sequenced. PLC IV is distinct from the other three types of rat PLC (PLC I, II, and III) with respect to primary structure and tissue distribution of its mRNAs. PLC IV contains two homologous regions included commonly in PLC I, II, and III and is most similar to PLC II (identity: 50.2%). PLC IV, in common with PLC II, has a sequence homologous to the N-terminal regulatory domains of nonreceptor tyrosine kinases of the src-family of oncogenes. Using an Escherichia coli expression system, we succeeded in producing active PLC IV in E. coli crude extracts. Various truncation experiments of the PLC IV cDNA revealed that the src-related domain is not necessary for catalytic activity while both domains homologous among PLC I-IV are essential. PLC IV is expressed in various rat tissues and abundant in spleen, suggesting that PLC IV plays a fundamental role in cellular functions such as growth and secretion.     

Functional defects of culture-grown bone marrow-derived macrophages from autoimmune MRL/MpJ-lpr/lpr mice

To investigate the primary defects and development of macrophages in MRL/MpJ-/pr/lpr (MRL/l) mice, we used a pure population of macrophages derived from bone marrow precursor cells cultured in the presence of L-cell conditioned medium (LCM) as a source of colony stimulating factor. Bone marrow-derived macrophages (BMM phi) from MRL/l mice had lower antigen presenting activity as detected by the induction of antigen-specific T cell proliferation, than age- and sex-matched control mice (CBA/J). Cell surface antigens (Ia and Mac-1) were determined quantitatively by a cell sorter as markers of macrophage differentiation. The BMM phi from MRL/l contained a much smaller number of Ia antigen-positive macrophages than those from normal mice. Treatment of BMM phi with an Ia-inducing of factor (IFN-gamma) markedly increased the expression of Ia antigens. This increase was significantly greater in BMM phi from MRL/l mice than in BMM phi from control mice. Expression of Mac-1 antigen was not different in BMM phi from the two strains. The Fc-mediated phagocytosis of IgG-coated sheep red blood cells was decreased in BMM phi from MRL/l mice compared with those from control mice. The function of nonspecific phagocytosis as measured by latex-bead incorporation was also impaired in MRL/l mice. The functional defects of MRL/l BMM phi found in these experiments are not secondary defects acquired under the influence of environmental signals during development, but are derived from the primary abnormalities which already exist in myeloid stem cells.     

Adhesive Property of Toxin-Coregulated Pilus of Vibrio cholerae O1

The adhesive property of toxin-coregulated pilus (TCP) to the human intestine (jejunum), and whether or not TCP mediates the adhesion of Vibrio cholerae 395 organisms to the intestinal epithelium were investigated using visually proving methods. The purified TCP did not agglutinate human erythrocytes nor adhere to the surface of human intestinal epithelium. V. cholerae 395 adhered to the epithelium, but the adhesion was not inhibited by blocking the pili with the Fab fraction of anti-TCP IgG. The organisms adhered to the intestine treated with purified TCP in advance, as well as to the intact intestine. These findings suggest that TCP is not involved in the adhesion of these organisms to the intestinal epithelium.     

Differential effects of various growth factors and cytokines on the syntheses of DNA,type I collagen,laminin, fibronectin,osteonectin/secreted protein,acidic and rich in cysteine (SPARC), and alkaline phosphatase by human pulp cells in culture

The purpose of this study is to differentiate roles of several growth factors and cytokines in proliferation and differentiation of pulp cells during development and repair. In human pulp cell cultures, laminin and type I collagen levels per cell remained almost constant during the whole culture period (22 days). On the other hand, secreted protein, acidic and rich in cysteine (SPARC/osteonectin) and alkaline phosphatase (ALPase) levels markedly increased after the cultures reached confluence. Laminin and type I collagen, as well as fibronectin, stimulated the spreading of pulp cells within 1 h. Adding transforming growth factor-β (TGF-β) decreased laminin and ALPase levels, whereas it increased SPARC and fibronectin levels 3- to 10-fold. Western and Northern blots showed that TGF-β enhanced SPARC synthesis at the protein and mRNA levels. Basic fibroblast growth factor (bFGF) decreased type I collagen, laminin, SPARC, and ALPase levels without changing the fibronectin level. Platelet-derived growth factor (PDGF) selectively decreased laminin, SPARC, and ALPase levels. Epidermal growth factor (EGF) also decreased SPARC and ALPase levels. Tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) decreased type I collagen and laminin levels, and abolished SPARC and ALPase syntheses. Of these peptides, bFGF and PDGF showed the greatest stimulation of [³H]thymidine incorporation into DNA. TGF-β, EGF, and TNF-α had less effect on DNA synthesis, whereas IL-1β inhibited DNA synthesis. These findings demonstrated that TGF-β, bFGF, EGF, PDGF, TNF-α, and IL-1β have characteristically different patterns of actions on DNA, laminin, type I collagen, fibronectin, ALPase, and SPARC syntheses by pulp cells. J. Cell. Physiol. 174:194–205, 1998. © 1998 Wiley-Liss, Inc.     

The expression of iron homeostasis-related genes during rice germination

To characterize Fe homeostasis during the early stages of seed germination, a microarray analysis was performed. mRNAs extracted from fully mature seeds or seeds harvested 1–3 days after sowing were hybridized to a rice microarray containing approximately 22,000 cDNA oligo probes. Many Fe deficiency-inducible genes were strongly expressed throughout early seed germination. These results suggest that the demand for Fe is extremely high during germination. Under Fe-deficient conditions, rice produces and secretes a metal-cation chelator called deoxymugineic acid (DMA) to acquire Fe from the soil. In addition, DMA and its intermediate nicotianamine (NA) are thought to be involved in long distance Fe transport in rice. Using promoter-β-glucuronidase (GUS) analysis, we investigated the expression patterns during seed germination of the Fe deficiency-inducible genes OsNAS1, OsNAS2, OsNAS3, OsNAAT1, and OsDMAS1, which encode enzymes that participate in the biosynthesis of DMA, and the transporter genes OsYSL2 and OsIRT1, which are involved in Fe transport. All of these genes were expressed in germinating seeds prior to protrusion of the radicle. These results suggest that DMA and NA are produced and involved in Fe transport during germination. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.