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We studied the effects of halothane on membrane potentials and ionic currents in single guinea pig atrial and ventricular cells prepared by an enzymatic dispersion procedure. In both atrial and ventricular cells, action potential overshoot and its plateau phase were significantly decreased by halothane (2%) without change in resting potential. However, the duration of the ventricular action potential measured at 90% repolarization was markedly shortened by halothane (2%) (to 60% of control), whereas that of the atrial action potential did not change significantly. Corresponding voltage clamp experiments demonstrated that in atrial cells halothane (2%) significantly depresses the time- and voltage-dependent outward K+ current (IK) (to 46% of control); and that in ventricular cells IK is then nearly absent. In both atrial and ventricular cells halothane had no effect on the inwardly rectifying K+ current (IK1). On the other hand, halothane (2%) decreased the slow inward Ca2+ current (ICa) in both atrial and ventricular cells (to 36% and 29% of control, respectively). The results suggest that the shortened action potential in ventricular cells by halothane may well be responsible for the decrease of the plateau phase resulting from the depression of ICa; and that in atrial cells the depression of IK and ICa by halothane had no significant effect on the duration of action potential.

The action of acetaldehyde on the membrane resistance of the guinea-pig taenia caecum was investigated with a double sucrose-gap method in different ionic environments. Application of acetaldehyde (10--20 mM) produced hyperpolarization, block of spike discharge and reduction of the membrane resistance. The reduction of the membrane resistance by acetaldehyde was potentiated by increasing the external K+ concentration and by replacement of Cl- with NO3-; it was reduced by lowering the external K+ concentration and by replacement of Cl- with benzenesulfonate. Replacement of NaCl with Tris-Cl, sucrose, or LiCl had no appreciable effect on the action of acetaldehyde on the membrane resistance. It therefore seemed likely that acetaldehyde increased the membrane conductance for K+ and Cl- more than for Na+. Although this action of acetaldehyde was similar to the alpha-action of catecholamine, the decrease of the membrane resistance and hyperpolarization induced by acetaldehyde remained unchanged in the presence of phentolamine.

The in vivo rates of protein synthesis in the peripheral nervous tissues of methylmercury-treated rats (10 mg/kg/day, for 7 days) have been estimated with improved methods by the injection of a large amount of [1-14C]valine of low specific activity. Protein synthesis activity in the dorsal root ganglia was inhibited to the extent of 60% of the control as early as day 5 and this continued to the symptomatic period (day 15) on which crossing of hind limbs, a typical sign of organomercurial poisoning, was observed in the animals. The sciatic nerves and dorsal roots increased protein synthesis by 56% at the symptomatic period. These increases in protein synthesis may be due to the stimulation of reactivity of Schwann's cells. On the contrary, the protein synthesis in the ventral roots showed a gradual decrease as the intoxication proceeded and decreased to 73% of the control at the symptomatic period, being similar to the case of brain. The double-labeling studies with sodium dodecyl sulfate/polyacrylamide gel electrophoresis exhibited that methylmercury inhibited the synthesis of the dorsal root ganglion proteins non-uniformly in various apparent molecular sizes, especially on day 10.

Halothane exerts negative inotropic and negative chronotropic actions on the isolated heart in experimental animals. In order to assess directly the actions of halothane in myocardium, we studied the effects of halothane on membrane potentials and transmembrane ionic currents in single isolated frog atrial cells obtained by the enzymatic dissociation method. The results show: (a) that the action potential is prolonged and its plateau phase and overshoot are depressed, but the resting potential remains unchanged; (b) that there is a significant inhibition of a time- and voltage-dependent outward K+ current and a slow inward Ca2+ current, with a slight decrease of a fast inward Na+ current following halothane (1.0-4.0%) application; and that halothane has no effect on another K+ current, time-independent current.

The effects of ketamine on contraction induced by depolarization of cell membrane (high K+-induced contracture) were studied in isolated vascular smooth muscle from rabbit portal vein. Ketamine in concentrations above 5 x 10(-4) M caused relaxation in phasic contraction, and above 10(-4) M caused relaxation in tonic contraction. These effects of ketamine at concentrations of between 10(-5) to 10(-3) M were dose dependent and reversible. In concentration above 10(-5) M, ketamine decreased the contractile response (tonic contraction) induced by 2.5 mM Ca2+ after the temporary contracture in Ca2+-free, high K+ solution. The contractile responses to norepinephrine (10(-6) M) or serotonin (10(-6) M) were also inhibited by ketamine. From these findings, it is concluded that ketamine decreases contractile responses due to transmembrane Ca2+ influx after depolarization of cell membrane and may decrease the contractile responses in concentration above 5 x 10(-4) due to Ca2+ release inhibition from sarcoplasmic reticulum.

No difference was observed during in vitro development between mouse single blastomeres with and without the zona pellucida, isolated from 2- and 4-cell stage eggs.

The glycogen of megakaryocytes and blood platelets has been investigated in glutaraldehyde and osmium tetroxide fixed tissues by the periodic acid-thiocarbohydrozide-silver proteinate method (PA-TCH-SP). The PA-TCH-SP method involves the staining of intracytoplasmic glycogens more densely than the routine lead citrate method. Glycogen having a mean particle diameter of 21.1 nm has been shown localizing in the matrix of mature megakaryocytes, while that of glycogen in the platelets was 26.2 nm. The staining pattern of the glycogen in blood platelets was classified into three groups according to staining intensity. It is found that the PA-TCH-SP method is a very suitable one for the demonstration of intracytoplasmic glycogen from the viewpoints of reaction specificity, reproducibility, fineness of reaction products, sufficiency of electron density, and experimental cost. This method is also a very useful one for differentiating intracytoplasmic glycogens and ribosomes.

The effect of acetaldehyde on the contractile responses induced by potassium-rich solution was studied in the guinea-pig taenia caeci. Acetaldehyde at a concentration between 1 and 50 mM reduced the tonic contraction induced by a high potassium solution containing a normal concentration of CaCl2 without affecting the phasic one. The phasic contraction was depressed only slightly at a very high concentration of acetaldehyde (100 mM). The tonic component increased with increasing external Ca concentration, and the reduction of this tonic contraction by acetaldehyde was greater at high Ca concentrations. In Ca-free, K-rich solution, carbachol induced a transient contraction. This carbachol-induced contraction in the absence of external Ca was markedly depressed at the second application of carbachol, but it reappeared after exposure to a Ca-containing solution. In this condition acetaldehyde did not affect these carbachol-responses, while it decreased a slow rise of tension during exposure of Ca. These results suggest that acetaldehyde inhibits the entry of external calcium without having an appreciable effect on the release of Ca and on the filling of the internal stores with Ca.

In order to demonstrate the localization associated with metabolism of an anti-allergic agent, Tranilast, in the liver, light microscopic radioautography of the liver was performed. Rats were administrated orally with 3H-Tranilast, and were sacrificed at 15 minutes to 24 hours after the administration. The livers were taken out and fixed, embedded and processed for light microscopic radioautography. 3H-Tranilast was absorbed rapidly, and the radioactivity in the liver increased and decreased within several hours. The number of radioautographic silver grains reached a maximum 3 hours after the administration. From 1 to 6 hours after the administration, the silver grains decreased from the portal area toward the central area. Seventy to 80% of all silver grains on the hepatocytes were retained in the cytoplasms of the hepatocytes at any experimental period. From these results, it was concluded that the localization of radioautographic silver grains was associated with Tranilast uptake of hepatocytes in each hepatic lobular compartment and that the metabolic process from uptake to excretion of Tranilast took part in the hepatocytes in each hepatic lobular compartment.

A case of oncocyte-type renal cell carcinoma was reported. The tumor had developed from the upper posterior portion of the left kidney and was well circumscribed. However, the tumor showed expansion into the intraparenchymal space, invasive growth, and venous invasion. Marked cell atypia was not observed.

In a carboxymethyl cellulose (CMC) air pouch inflammation model, accumulation of exudate decreased at a relatively rapid rate and almost disappeared 3 days after a 2% CMC injection into the preformed air pouch. After a second injection of 2% CMC solution into the 1-day-old CMC pouch on the day following the first CMC injection, the decrease in rate of exudate was similar to the change seen after the first CMC injection. In another group of rats, 3 days after the first CMC injection when inflammation had subsided, a second injection of 2% CMC solution into the 3-day-old CMC pouch resulted in a marked increase of exudate accumulation, inflammatory cell infiltration and vascular permeability. Histologically, large numbers of macrophages accumulated in the 3-day-old CMC pouch and fibroblast proliferation and newly formed blood vessels were also visible. The enhanced exudative reaction was significantly inhibited by dexamethasone but not by indomethacin. These results indicate that the enhanced inflammatory reactions appear to be closely correlated with the increase of reactivity at the site of inflammation and the exudative reaction was not mediated by cyclo-oxygenase products.

We describe a novel temperature-controlled perfusion apparatus for electrophysiological studies on isolated cells or membrane patches. The apparatus uses a transparent conducting film of indium-tin-oxide as a heating element. The film heater deposited on a glass sheet allows us to construct a structurally simple apparatus that is able not only to heat directly the bath chamber but also to preheat the perfusion solution on the stage of an inverted microscope. The structure ensures a uniform temperature in a bath chamber that has a working area of approximately 6 X 12 mm2 and a capacity of 1 ml. A control unit, designed for operation of the apparatus, regulates the temperature of the bathing solution without introducing electrical noise in a range from ambient temperature to greater than 37 degrees C with an accuracy within +/- 1 degree C. The apparatus is 12 mm in height and designed to fit on the stage of a standard inverted microscope. Since the bath chamber for perfusion experiments is readily interchanged with others, the apparatus can be used widely in microscopic studies of various cells in static solutions.

Secondary proliferous melanoic tumors grew at 100% of probability in a liver lobe of C57BL/6 mouse with a piece of B16 melanoma tumor embedded successfully in the lobe. Clear border between host liver tissues and the embedded tumor piece was observed 14 days after embedding. No division image was noted in cells of the embedded tumor piece. In all regions surrounding the embedded tumor piece, there were few accumulations of leucocytes, lymphocytes, or giant cells, indicating a strong likelihood of immune reaction or antigen-antibody reaction, although there was active formation of fibroblast bunds and production of lysosomal enzymes. Secondary proliferous melanoic tumors developed in the environment of liver tissue separately from the embedded tumor location. Results of 14C-thymidine-nuclear labeling of embedded tumor cells showed that the majority of the labeled cells did not migrate or divide. In the case of 14C-thymidine-labeling of host liver tissue cells, results indicated no transfer of 14C-radioactivity into nuclei of embedded tumor cells, although there was positive distribution of 14C-radioactivity into nuclei of proliferous cells in the secondary tumor, a newly developed melanoic cell group. When prelabeling was performed the average density of autoradiographic image over the secondary tumor was equivalent to that over the normal liver tissue at the early stage such as 7 days after embedding and decreased with time after that. The newly developed melanoic cells were particularly exciting and proliferous, because they received much more labeling of 14C-thymidine as compared to liver tissue cells that was provided by one shot labeling of the radioactive tracer 1 h. before sacrifice of tumor embedded mice. There was no development of secondary melanoic cells in the liver lobe in case of embedding of a tumor piece previously by wrapping with a membranefilter, less 5 microns in pore size.