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Biomedical subjects

K Kanai

Publications and source records attributed to K Kanai.

At least 145 records · Page 8Linked to original sources
PubMed1987

Glucose 6-phosphatase and glycogen phosphorylase activities in chondrocytes in epiphyseal cartilage of growing rats.

Glycogen, glycogen phosphorylase, and glucose 6-phosphatase (G6Pase) activities were examined cytochemically in chondrocytes of femoral epiphyseal cartilages and cartilaginous ribs of 3- and 7-day-old rats. G6Pase activity was also examined biochemically. Glycogen was abundant in chondrocytes of the reserve zone, while it became scarce in the cells of the proliferative zone. From the upper part (adjoining the proliferative zone) to the lower part of the hypertrophic zone, glycogen accumulated in chondrocytes and decreased in the cells of the degenerative zone. Inversely, glycogen phosphorylase a and G6Pase activities were relatively high in chondrocytes of the proliferative zone and upper hypertrophic zone and were low in the cells of the reserve zone, lower hypertrophic zone, and degenerative zone. The reaction product for G6Pase was present in the endoplasmic reticulum and nuclear envelope of all types of chondrocytes composing the cartilages, although the amounts of reaction product varied with the cell types in parallel with the histochemical results. Biochemical G6Pase activity was higher in epiphyseal cartilages than in cartilaginous ribs. The possible mechanism and significance of the accumulation and decrease of glycogen in chondrocytes of the epiphyseal cartilage were discussed.

Animals↗
PubMed1987

Relationship between natural killer activity and development of hepatocellular carcinoma in patients with cirrhosis of the liver.

Natural killer (NK) activities of peripheral blood lymphocytes (PBL) in 50 patients with non-alcoholic liver cirrhosis (LC) were prospectively studied in order to clarify the relation between the development of hepatocellular carcinoma (HCC) and impaired NK activities. Patients were divided into two groups according to their NK activities at the beginning of the study, namely, Group A with normal NK activity (n = 21) and Group B with decreased NK activity (n = 29). NK activities were serially determined in each patient for up to 40 months. During the observation period, the occurrence of HCC was identified in 12 patients (four to 36 months). Of the patients who developed HCCs, two belonged to Group A (9.5%) and 10 belonged to Group B (34.5%). These results suggest decreased NK activity in LC patients to be one of the critical factors increasing their risk of developing HCC, and serial determinations of NK activities to be important in predicting the occurrence of HCCs in following the clinical course of LC patients.

Carcinoma, Hepatocellular↗
PubMed1986

[A statistical approach to pruritus senilis].

The purpose of this study is to analyse the cause of itching and explore the relationships between pruritus senilis and various stimuli. Sample of 132 men and 238 women with ages ranging from 60 to 96 years were used in our study. Pruritus senilis is not significantly related to cosmetics and soap. Nevertheless, statistically significant correlations were found between pruritus senilis and physical stimuli (e. g., warmth, coldness, dryness). These observations could suggest that pruritus senilis is caused by changes of temperature.

Aged↗
PubMed1986

Peri- and postnatal development of heterogeneity in the amounts of endoplasmic reticulum in mouse hepatocytes.

The surface density and area per cell of the endoplasmic reticulum (ER) in periportal and perihepatic hepatocytes from male ddY mice, "17-, 18-, and 19-day-old fetuses," "newborn and 1-, 5-, 10-, and 20-day-old animals," and "adult animals" were analyzed by quantitative electron microscopy. The surface density of rough ER was not significantly different between periportal and perihepatic cells in all age groups examined, except for 19-day-old fetuses in which the value was greater in periportal cells than perihepatic cells. The surface density of smooth ER and total (rough and smooth) ER did not significantly differ between the periportal and perihepatic cells from 17-day-old fetuses to 5-day-old animals. In 10- and 20-day-old and adult animals, the values of smooth and total ER were greater in perihepatic cells than in periportal cells. When the data were expressed as area per cell, the patterns of subacinar distributions hardly differed, but age-related changes differed considerably from the patterns seen in the surface density data. The differences were generally caused by the increase in hepatocyte volume between 20 days of age and adulthood, especially in perihepatic cells, and by the changes in volume during the perinatal period. The results show that differences in the surface density and area per cell of smooth and total ER between periportal and perihepatic hepatocytes evident in adult animals are not present in fetal and newborn animals but arise during postnatal development.

Age Factors↗
PubMed1986

Plasma membrane reregionalization in cultured mouse hepatocytes.

The cytochemical localization of alkaline phosphatase (ALPase) activity and the autoradiographic distribution of glucagon receptors were examined in the plasma membrane of cultured mouse hepatocytes. After 24 hours of culture, ALPase activity was exclusively localized on the plasma membrane in areas of cell-cell contact, and glucagon receptors were more numerous in the plasma membrane at the periphery of re-formed cell trabeculae. These results indicate that plasma membrane regionalization of hepatocytes, lost by cell isolation, reappeared during culture. The cells maintained this plasma membrane regionalization until 48 hours of culture. By 72 hours of culture, however, ALPase activity was seen on the external surface of all regions of plasma membrane, and the glucagon receptors decreased markedly in number and became scattered in all regions of plasma membrane. Thus, the re-formed plasma membrane regionalization disappeared in the cells by 72 hours of culture.

Alkaline Phosphatase↗
PubMed1986

Cytochemical and biochemical glucose 6-phosphatase activity in skeletal muscle cells of mice.

Cytochemical and biochemical glucose 6-phosphatase (G6Pase) activity and fiber type composition were studied in soleus (SOL) and gastrocnemius (GC) muscles of mice. The SOL is a red muscle which contains numerous type I fibers (60%) and relatively few type II fibers (40%). The GC is a white muscle which contains numerous type II fibers (90-100%) and very few type I fibers (0-10%). In the SOL and GC, cytochemical G6Pase activity was localized in the sarcoplasmic reticulum, lateral elements of triads, myonuclear envelope, and in the endoplasmic reticulum and nuclear envelope of endothelial cells. Differential centrifugation showed that G6Pase activity was recovered in the 105,000g pellet (microsomal fraction). Histochemical enzyme activity in type II fibers was slightly higher than that in type I fibers. Biochemical G6Pase activity in the GC was significantly higher than that in the SOL. The possible functional significance of G6Pase in skeletal muscles was discussed.

Animals↗
PubMed1986

Glucose 6-phosphatase activity in pregnant and lactating mammary glands of the mouse.

Glucose 6-phosphatase activity was studied in the secretory epithelial cell and other cell types composing alveoli of the mammary gland (cytochemical study) and in the whole mammary gland (biochemical study) of pregnant and lactating mice. The reaction product for the enzyme activity was seen in the endoplasmic reticulum and nuclear envelope in secretory epithelial cells from all animals examined (days 7 and 14 of pregnancy, and days 0, 3, 10, and 20 of lactation. The amounts of the reaction product appeared scarce at day 7 of pregnancy, moderate at day 14 of pregnancy and day 0 of lactation, and abundant at days 3 and 10 of lactation. The reaction product, however, became generally scarce at day 20 of lactation. Biochemical activity was relatively low at days 7 and 14 of pregnancy and days 0 and 20 of lactation, while it was high at days 3 and 10 of lactation. The increased activity is probably related to functions of secretory epithelial cells in the lactating gland.

Animals↗
PubMed1986

Surface markers of NK cells in peripheral blood of patients with cirrhosis and hepatocellular carcinoma.

The surface markers and NK activity of blood lymphocytes in 38 normal controls, 57 cirrhotic patients and 22 cirrhotics with hepatocellular carcinoma were studied by the flow cytofluorometry using monoclonal antibodies. A reduction of OKM1+ cells was remarkable in cirrhotics, and a further decrease in HNK-1+ cells as well as OKM1+ cells was observed in cirrhotics with hepatocellular carcinoma, accompanied by depression of NK activity. We postulate that the decreased NK activity in these patients may result from the disturbed maturation of NK cells.

Aged↗
PubMed1986

Morphometric analysis of fetal rat hepatocytes cultured in monolayer or following gyratory shaking.

The stereological technique was used to quantify glycogen areas and endoplasmic reticulum in fetal rat hepatocytes cultured for 24 hr in monolayer (monolayer cells) or following shaking by gyratory rotation (shaken cells). The volume density and volume per cell of glycogen areas decreased in order of freshly isolated hepatocytes, monolayer cells, and shaken cells. The surface density and area per cell of smooth endoplasmic reticulum increased in order of freshly isolated cells, monolayer cells, and shaken cells. The results show that the decrease of glycogen areas and proliferation of the smooth endoplasmic reticulum are more prominent in shaken cells than in monolayer cells. Prominent proliferation of the smooth endoplasmic reticulum in shaken cells may be due to the consumption of glycogen for energy release as a result of gyratory rotation.

Animals↗
PubMed1986

A time- and voltage-dependent K+ current in single cardiac cells from bullfrog atrium.

Individual myocytes were isolated from bullfrog atrium by enzymatic and mechanical dispersion, and a one-microelectrode voltage clamp was used to record the slow outward K+ currents. In normal [K+]o (2.5 mM), the slow outward current tails reverse between -95 and -100 mV. This finding, and the observed 51-mV shift of Erev/10-fold change in [K+]o, strongly suggest that the "delayed rectifier" in bullfrog atrial cells is a K+ current. This current, IK, plays an important role in initiating repolarization, and it is distinct from the quasi-instantaneous, inwardly rectifying background current, IK. In atrial cells, IK does not exhibit inactivation, and very long depolarizing clamp steps (20 s) can be applied without producing extracellular K+ accumulation. The possibility of [K+]o accumulation contributing to these slow outward current changes was assessed by (a) comparing reversal potentials measured after short (2 s) and very long (15 s) activating prepulses, and (b) studying the kinetics of IK at various holding potentials and after systematically altering [K+]o. In the absence of [K+]o accumulation, the steady state activation curve (n infinity) and fully activated current-voltage (I-V) relation can be obtained directly. The threshold of the n infinity curve is near -50 mV, and it approaches a maximum at +20 mV; the half-activation point is approximately -16 mV. The fully activated I-V curve of IK is approximately linear in the range -40 to +30 mV. Semilog plots of the current tails show that each tail is a single-exponential function, which suggests that only one Hodgkin-Huxley conductance underlies this slow outward current. Quantitative analysis of the time course of onset of IK and of the corresponding envelope of tails demonstrate that the activation variable, n, must be raised to the second power to fit the sigmoid onset accurately. The voltage dependence of the kinetics of IK was studied by recording and curve-fitting activating and deactivating (tail) currents. The resulting 1/tau n curve is U-shaped and somewhat asymmetric; IK exhibits strong voltage dependence in the diastolic range of potentials. Changes in the [Ca2+]o in the superfusing Ringer's, and/or addition of La3+ to block the transmembrane Ca2+ current, show that the time course and magnitude of IK are not significantly modulated by transmembrane Ca2+ movements, i.e., by ICa. These experimentally measured voltage- and time-dependent descriptors of IK strongly suggest an important functional role for IK in atrial tissue: it initiates repolarization and can be an important determinant of rate-induced changes in action potential duration.

Animals↗
PubMed1986

High and testosterone-dependent glucose 6-phosphatase activity in epithelium of mouse seminal vesicle.

For study of the mechanism of seminal fructogenesis, glucose 6-phosphatase activity was examined cytochemically (a method modified from that of Wachstein and Meisel) and biochemically (the method of Leskes et al.) in seminal vesicles from normal, castrated, and castrated and testosterone-treated mice. The reaction product for the activity was localized in the endoplasmic reticulum and nuclear envelope of all cell types composing the seminal vesicle. In normal seminal vesicle, the reaction product was apparently more abundant in columnar and basal cells than in other cell types. Ten, 20, and 30 days after castration, the abundant amount of reaction product in columnar and basal cells decreased to the level in other cell types. In animals treated with testosterone after castration, however, the reaction product in columnar and basal cells remained abundant. If fructose 6-phosphate was added to the reaction medium in place of glucose 6-phosphate, the amount and pattern of deposition of the reaction product did not change. Changes in biochemical activity in castrated or castrated and testosterone-treated animals paralleled the cytochemical results. The results show that the high activity in columnar and basal cells is under the control of testosterone, and the role of this enzyme is probably to release fructose into the seminal fluid.

Animals↗
PubMed1986

Triton WR-1339 as a biological-response modifier in mycobacterial infection.

A non-ionic detergent, Triton WR-1339, prolonged markedly the survival time of mice infected fatally with virulent mycobacteria, though it exerted only a limited effect on the fate of tissue viable counts. The combined administration of Triton WR-1339 with lentinan (a glucan purified from the Japanese mushroom Lentinus edodes) was more effective than the single administration of each. This detergent was not lytic to red blood cells or lysosomes, but its substantial effect on the biomembrane was suggested by cold-shock experiment of hemolysis. It was considered that Triton WR-1339 is a biological-response modifier, possibly altering the interaction between the mycobacterial surface and the membrane structure of phagocytes.

Animals↗
PubMed1986

Ultrastructural studies on the effect of Triton WR-1339 on macrophage-mycobacteria interaction.

Mycobacterium bovis (BCG organisms) suspended in saline or a 5% solution of a non-ionic detergent, Triton WR-1339, was injected intraperitoneally into mice. Electron-microscopic observation was carried out on peritoneal exudate cells harvested therefrom. Electron-lucent vacuoles limited by the membrane structure were found in macrophages of the mice injected with BCG suspended in the detergent, but not in polymorphonuclear leukocytes or lymphocytes. Mycobacterial cells were present within such vacuoles. Without the detergent, the ingested mycobacterial cells were in close contact with the phagosomal membrane. Within the electron-lucent vacuoles, however, such close contact was not present. These observations, together with other collateral findings, led us to a view that Triton WR-1339 may inhibit the interaction between mycobacteria and the phagosomal membrane by intervening between them thus making the progress of infection delayed.

Animals↗
PubMed1986

Bactericidal activity of the membrane fraction isolated from phagocytes of mice and its stimulation by melittin.

The membrane fraction prepared from mouse peritoneal exudate cells was incubated with mycobacteria, staphylococci, or E. coli in acetate buffer of pH 5.6 to follow the fate of viable bacilli. The membrane fraction exhibited bactericidal effect on mycobacteria and staphylococci, but not on E. coli. The activity to kill mycobacteria, as well as the endogenous phospholipase A2 activity, of the membrane fraction was markedly enhanced by melittin, a basic peptide from bee venom, and inhibited by indomethacin and EDTA. The role of the enzyme activity in the bactericidal activity was discussed.

Animals↗