Myosin heavy chain composition of tongue muscle in microphthalmic (mi/mi) mice before and after weaning.

To elucidate the effects of teeth on muscle fibers in the tongue during the developmental process, we examined the expression of muscle contractile proteins and the genes for those proteins in normal mice and microphthalmic (mi/mi) mice with impaired tooth eruption. The mice were observed during the growth period, including weaning, which is when feeding movements undergo major changes. Expression of the myosin heavy chain (MyHC)-2a protein, whose contraction speed is relatively slow, disappeared after weaning in normal mice, while it remained in high concentrations even after weaning in mi/mi mice. The presence of MyHC-2a after weaning in mice with no tooth eruption was attributed to a compensation for lack of proper masticatory function and sucking-like movements, as MyHC-2a is necessary for these movements.     

Hepatic Disposition Characteristics of Electrically Charged Macromolecules in Rat in Vivo and in the Perfused Liver

The effect of electric charge on the hepatic disposition of macromolecules was studied in the rat. Charged derivatives of dextran (T-70) and bovine serum albumin (BSA), mitomycin C–dextran conjugates (MMC-D), and lactosaminated BSA (Lac-BSA) were employed as model macromolecules. After intravenous injection, cationic macromolecules were rapidly eliminated from plasma because of their extensive hepatic uptake, while anionic and neutral macromolecules were slowly eliminated. Cationic macromolecules were recovered from parenchymal and nonparenchymal hepatic cells at a cellular uptake (per unit cell number) ratio of 1.4–3.2, while that of Lac-BSA was 14. During liver perfusion using a single-pass constant infusion mode, cationic macromolecules were continuously extracted by the liver, with extraction ratios at steady-state (E _ss) ranging between 0.03 and 0.54, whereas anionic and neutral macromolecules were almost completely recovered in the outflow at steady state. The E _ss for cationized BSA (Cat-BSA) and cationic MMC-Dcat were concentration dependent and decreased at low temperatures and in the presence of colchicine and cytochalasin B. The possible participation of the internalization process in the uptake of cationic macromolecules by hepatocytes was suggested.     

CLINICAL EVALUATION OF PERORAL CHOLANGIOSCOPY FOR BILIARY DISEASE USING NARROW BAND IMAGING

Regarding peroral cholangioscopy (POCS) for biliary disease, due to the recent appearance of a video cholangioscope that can obtain high‐quality images, it is possible to observe subtle changes of the biliary mucosa. In addition to the conventional observation method using POCS, the biliary mucosa with also observed with narrow band imaging (NBI) in one case of chronic cholangitis and four cases of extra hepatic bile duct tumor (three surgical cases). In the conventional observation method, the vessels in the surface layer of the biliary mucosa could be observed more clearly using NBI. In one case in which a tumor was observed, the irregularity of the biliary mucosa became clear on NBI, and the vessels inside a papillary tumor could also be easily observed. In another case of bile duct tumor, the conventional observation method showed a region in the proximity of the tumor where the vessels could not be seen clearly, but they could be seen clearly on NBI. In all of the cases, the bile juice was seen as red on NBI, which disturbed the observation. With POCS using NBI, it was possible to observe the vessels and irregularities in the surface layer of the biliary mucosa more clearly than with conventional observation methods.     

Obstinate cough as a sole presenting symptom of non-metastatic renal cell carcinoma

Renal cell carcinoma (RCC) causes many kinds of symptoms such as hypercalcemia, hypertension, polycythemia and fever. Here we describe a rare case of RCC presenting with a persistent cough. After radical nephrectomy, the obstinate cough disappeared. When the tumor recurred locally, the cough also recurred. Furthermore, the cough disappeared completely again after the removal of the recurrent tumor. Although all the clinical findings suggested that the RCC caused the cough, we could not identify a specific humoral substance responsible for the cough.     

Protective effect of prostaglandins D2, E1 and I2 against cerebral hypoxia/anoxia in mice

The protective effect of prostaglandins (PGs) against cerebral hypoxia/anoxia was investigated with a variety of experimental models in relation to their CNS depressant effects in mice. Furthermore, the effect of PGs on the changes of cerebral energy metabolites and cyclic nucleotide was examined in hypoxic mice. Mice were given s.c. doses of PGs 30 min before tests. Among the PGs tested, treatment with PGD2, PGE1 and PGI2 Na showed a consistent and dose-dependent protection against cerebral anoxia induced by all models studied: histotoxic anoxia by KCN, hypobaric hypoxia, normobaric hypoxia and decapitation-induced gasping. However, PGA1, PGA2, PGB1, PGB2, PGE2, PGF1 alpha, PGF2 alpha and 6-keto-PGF1 alpha at a dose of 3 mg/kg were without effect against normobaric hypoxia and gasping duration. The three PGs, i.e. PGD2, PGE1 and PGI2 which showed anti-hypoxic effects decreased locomotor activity and potentiated hexobarbital-induced sleep. On the other hand, PGE2, PGA1, PGA2 and PGB2 also caused a decrease in locomotor activity. Similarly, PGE2 and PGA1 caused a potentiation of hexobarbital-induced sleep, but interestingly they did not cause clear-cut increase in cerebral resistance to hypoxia, in contrast with the former three PGs. Thus general depression of CNS function appears not to be responsible for the PGD2-, PGE1- and PGI2-induced increase in cerebral resistance to hypoxia. The levels of Cr-P and ATP were significantly reduced and those of ADP and AMP were markedly elevated in hypoxic brain, resulting in a decrease in a calculated energy charge potential. The lactate level and lactate/pyruvate ratio increased and the glucose level decreased markedly.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mouthguards: difference in longitudinal dimensional stability between single- and double-laminated fabrication techniques

Abstract –  Though the use of mouthguards (MGs) has increased with the increase in sporting activities, little is known about the influence of their fabrication methods on longitudinal dimensional stability. The objective of this study was to compare the difference in the longitudinal dimensional stability between single and laminated MGs. Single-layer MGs were made from a 4.0 mm thick ethylene vinyl acetate (EVA) sheet and laminated MGs were made from two 2.0 mm thick sheets of EVA. MGs were kept in a 37°C water bath for 60 h, equivalent to the time period of 3-months inter-oral use. MG deformation was analyzed by measuring designated points on the MG border using a profile projector (J-12, Nikon Inc., Tokyo, Japan) before and after the water immersion. A finite-element model was also created to examine the time course of stress accumulation during the sheet forming process using Finite Element software. Longitudinal deformation was smaller in the laminated MGs than in the single-layer MGs in the anterior area ( P  < 0.05). Finite element method (FEM) analysis also showed the largest stress accumulation in the anterior incisal area where deformations were mainly observed. Laminated double layer MGs have advantages over single-layer MGs in terms of longitudinal stability due to lower stress accumulation during the fabrication process.     

Disposition Characteristics of Macromolecules in Tumor-Bearing Mice

As part of the strategy for the design of macromolecular carriers for drug targeting, the disposition characteristics of macromolecules were studied in mice bearing tumors that served as target tissues. Eight kinds of macromolecules including four polysaccharides and four proteins with different molecular weights and electric charges were used; tissue distribution and tumor localization after intravenous injection were studied. Pharmacokinetic analysis revealed that the tissue radioactivity uptake rate index calculated in terms of clearance was different among the tested compounds; especially, the urinary radioactivity excretion clearances and the total hepatic radioactivity uptake clearances varied widely. Compounds with low molecular weights (approximately 10 kD) or positive charges showed lower tumor radioactivity accumulation; radioactivity was rapidly eliminated from the plasma via rapid urinary excretion or extensive hepatic uptake, respectively. On the other hand, large and negatively charged compounds, carboxymethyl dextran, bovine serum albumin, and mouse immunoglobulin G, showed higher radioactivity accumulation in the tumor (calculated total amounts were 15.6, 10.8, and 20.8% of the dose, respectively) and prolonged retention in the circulation. These results demonstrated that the total systemic exposure rather than the uptake rate index was correlated with total tumor uptake. Molecular weight and electric charge of the macromolecules significantly affected their disposition characteristics and, consequently, determined radioactivity accumulation in the tumor. It was concluded that a drug–carrier complex designed for systemic tumor targeting should be polyanionic in nature and larger than 70,000 in molecular weight.