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M Kasai

Publications and source records attributed to M Kasai.

At least 451 records · Page 25Linked to original sources
PubMed1984

Channel selectivity and gating specificity of calcium-induced calcium release channel in isolated sarcoplasmic reticulum.

Mg2+ and Ca2+ efflux rates from sarcoplasmic reticulum vesicles were measured by using a fluorescence chelate probe, chlortetracycline. Mg2+ efflux rate was almost the same as Ca2+ efflux rate under the same medium conditions. Both effluxes were activated by micromolar concentrations of extravesicular Ca2+ and blocked by millimolar concentrations of extravesicular Ca2+. Both effluxes were also activated by caffeine and inhibited by procaine. This result shows that Mg2+ can permeate through the Ca2+-induced Ca2+ release channel at the same rate as Ca2+: namely this channel has no selectivity between Ca2+ and Mg2+. Gating specificity of the channel was studied by measuring Mg2+ efflux. It was shown that this channel could be opened by Sr2+ as well as Ca2+, but not by Ba2+ or Mg2+. The apparent dissociation constant of the activation site for Sr2+ was slightly higher than that for Ca2+ but the apparent dissociation constant of the inhibition site for Sr2+ was almost the same as that for Ca2+.

Animals↗
PubMed1984

Fertilization in vitro of cattle follicular oocytes with ejaculated spermatozoa capacitated in a chemically defined medium.

Cattle follicular oocytes were collected from the ovarian follicles and cultured for 28 h in m-KRB solution in a CO2 incubator (5% CO2 in air at 37 degrees C, 95% humidity). After further culture for 15-18 h with spermatozoa, 78.6% of the oocytes had matured to the second metaphase. The highest fertilization rates (36-58%) were obtained when spermatozoa were collected 1 day before insemination, kept for 14-18 h at 20 degrees C in a test tube (10 X 10(8)/ml), preincubated in m-KRB solution (1-1.2 X 10(8)/ml) in a CO2 incubator for 0-12 h, and then inseminated at a concentration of 1.5-2.0 X 10(6)/ml. The optimum period of preincubation in the CO2 incubator was 8 h: 6/15 denuded oocytes (40%) were fertilized with spermatozoa preincubated for 8 h. No polyspermic fertilization was observed in any of the 139 penetrated oocytes. When spermatozoa were preincubated in the uteri of oestrous cows and gilts for 4-4.5 h instead of the m-KRB solution, the fertilization rates were 80 and 86%, respectively. However, in this system, 13 and 24% of the penetrated oocytes were polyspermic. These results indicate that ejaculated bull spermatozoa can be capacitated in a chemically defined isotonic medium, and about half of the oocytes matured in culture are normally fertilized in vitro.

Animals↗
PubMed1984

Plasma growth hormone responses to sulpiride in patients with acromegaly.

The role of endogenous dopamine (DA) on plasma GH secretion was studied in 12 patients with active acromegaly. After intramuscular administration of 100 mg sulpiride, 3 out of 12 patients showed distinct increases in their plasma GH (cases 1-3: sulpiride-responders). The GH increases far exceeded the ranges of physiological fluctuation in two cases studied (case 1 & 3). After domperidone administration, case 3 showed a quite similar GH increase as after sulpiride. Plasma GH responses to TRH and sulpiride were still observed in case 2 even after the basal GH levels were normalized by the transsphenoidal hypophysectomy. The three sulpiride-responders showed so-called paradoxical GH decreases following the administration of L-dopa (500 mg, p.o.) or DA (5 micrograms/kg/min over 90 min, i.v.). However, the basal plasma PRL levels and the responses to sulpiride in these 3 cases were not homogeneous. These results indicate that endogenous DA has a tonic inhibitory effect on GH secretion in some cases of acromegaly, and that tumorous somatotrophs rather than elevated GH levels are the critical factor for such inhibition. Further, the sensitivities of somatotrophs and lactotrophs to DA appeared to be heterogeneous in acromegalic patients.

Acromegaly↗
PubMed1984

The mechanism of postinhibitory rebound increases in plasma gh in acromegalic patients.

The mechanism of postinhibitory rebound increase in GH secretion was studied in 5 normal and 7 acromegalic subjects. Both normal and acromegalic subjects showed prompt GH decreases during the infusion of somatostatin (500 micrograms/75 min) (% decrease: 69.1 +/- 10.4 vs. 73.9 +/- 6.5) and rebound rises after its termination. The rebound rises occurred more promptly and markedly in normal controls than in acromegalic subjects, i.e. the rebound peak appeared at 15 min in normal controls and at 45 min in acromegalic patients after the cessation of somatostatin infusion. Dopamine (DA) infusion (5 micrograms/kg/min for 90 min) also induced similar inhibition and postinhibitory rebound rises in GH secretion in 6 patients with acromegaly. Although the maximum inhibitions (67.1 +/- 7.3% vs. 73.7 +/- 7.1%) and the inhibitory areas (4354.5 +/- 471.0% . min vs. 3796.5 +/- 322.5% . min) during the DA and somatostatin infusions were not different, the rebound at 15 min was significantly greater after DA than after somatostatin (p less than 0.05). All seven patients with acromegaly were TRH responsive in their plasma GH (% of basal: 93.5 to 944.3). When TRH was injected at the termination of somatostatin infusion, the rebound increase was significantly enhanced and the rebound peak appeared 30 min earlier than after single somatostatin administration. These results indicate that the mechanisms participating in the postinhibitory rebound rise are different in normal controls and acromegalic patients, and that the magnitude of the rebound differs with agents employed. Also, it is evident that the rebound phenomenon in acromegaly is possibly modified by exogenous hypothalamic releasing factors.

Acromegaly↗
PubMed1984

Primary culture of human esophageal epithelial cells.

Primary cultures and serial passages of nontumorous adult human esophageal epithelial cells derived from surgically resected esophagi of patients with esophageal cancer have been developed. Disaggregated cells obtained by means of tryptic digestion lasting for 90 min grew to confluency in medium RITC 80-7 supplemented with 10% fetal bovine serum (FBS). Such primary cultures were established from more than 20 donors, and could be passaged 3 to 5 times. Fibroblastic contamination was almost eliminated by careful sampling, and it was possible to perform the growth response or serial passages without fibroblastic overgrowth. Serum-free medium RITC 80-7 supplemented with fibronectin (FN) and bovine serum albumin (BSA) also supported the growth of esophageal epithelial cells, but was not sufficient for serial passages. Among growth promoting factors in medium RITC 80-7, the epidermal growth factor (EGF) was highly stimulatory to growth. Insulin, transferrin, FN and BSA also enhanced cell growth and/or attachment. The epithelial nature of the cultured cells was confirmed by transmission electron microscopy and indirect immunofluorescent staining with antikeratin antibody. The majority of the cultured cells were diploid.

Adult↗
PubMed1984

[Prevention of 5-FU induced toxicity in C3 H/HE mice with interferon or with interferon inducers (poly 1: C, OK-432, Lentinan)].

It is well known that all cell lines, normal as well as malignant, have a sensitivity to the growth-inhibitory effect of Interferon, or Interferon inducers. 5-FU is a widely used anticancer drug considered to be a cell cycle-specific agent. We speculated that the antiproliferative effect of Interferon or Interferon inducers might affect the activity of 5-FU and diminish the uncomfortable side-effects of this agent. Initially this experiment, we observed the mortality rate in mice after administration of 5-FU alone, or 5-FU plus Interferon (alpha inducers). We then carried out cytofluorometric observation of bone marrow cells, and finally studied the influence of Interferon (or inducers) on the anticancer effects of 5-FU against MM48 tumors in C3/He mice. Findings were as follow: 1) Administration of beta-type Interferon for 2 days, following the administration of a toxic dose (140 mg/kg/w) of 5-FU, revealed significant protection from mortality in C3H/He mice. This effect was also observed when Interferon inducers (Poly I: C, OK-432, Lentinan) were administered with 5-FU. Body weight loss was 10.4% at nadir in mice treated with 5-FU alone, while there was a body weight gain of 36.3% in mice treated with 5-FU plus Interferon. 2) Cytofluorometry of bone marrow cells obtained from mice femur at timed intervals after the administration of OK-432, or Lentinan indicated that these drugs inhibited the entry of cells into the S-phase, causing then to accumulated in the G0.G1-phase during the first 48 hours. 3) Histological findings of intestinal mucosa in mice showed prominent destruction after bolus injection of 350 mg/kg of 5-FU alone, while these findings were not observed in mice after the bolus injection of 350 mg/kg of 5-FU combined with Interferon. 4) The tumor volume ratio (T/C) was significantly reduced in the group treated with 5-FU alone as well as that treated with 5-FU combined with Interferon (or inducers) in C3H/He mice bearing MM48 tumors. All mice were dead about 2 weeks after administration of 5-FU alone, while all mice treated with 5-FU plus Interferon (or inducers) were alive in the same period. From these results, we speculate that Interferon, or Interferon inducers play an important role in the prevention of side effects of cell cycle-specific cytotoxic drugs like 5-FU, without decreasing their anticancer activity.

Animals↗
PubMed1984

[Cytophotometric DNA analysis of the early and superficial esophageal cancer].

Although it is widely known that early esophageal cancer (n-) patients have a favorable prognosis after surgery and the superficial esophageal cancer (n+) patients have a poor one, the differences between them have not been found out under the microscopic examination of the primary lesion. Cytophotometric DNA analysis of the primary lesion was done to search for the differences between early and superficial esophageal cancer. Significant differences were obtained in the mean DNA value (p less than 0.01), the percentage of nuclei beyond tetraploid (p less than 0.001) and the product of 2 indices above (p less than 0.001). The result suggests that cytophotometric DNA analysis is a useful means for differentiating the early esophageal cancer from the superficial esophageal cancer and that the most suitable perioperative combined therapy can be chosen through the Feulgen-stained biopsy specimen.

Aged↗
PubMed1984

HPLC analysis of E. coli rRNA on ASAHIPAK GS-520 and nucleobases, nucleosides and nucleotides on ASAHIPAK GS-320.

High-performance gel filtration chromatography using packed column Asahipak GS-520 was employed to separate E. coli 23S, 16S and 5S rRNAs. Low-molecular-weight components of nucleic acid were separated with Asahipak GS-320. Concurrent, rapid analysis of nucleobases, nucleosides and nucleotides was obtained isocratically. The elution of these substances is also described.

Chromatography, High Pressure Liquid↗
PubMed1984

[Progress in postoperative care and postoperative combined therapy of esophageal carcinoma by total parenteral nutrition (TPN)].

Intravenous hyperalimentation which consisted of 30% hypertonic glucose solution and 10% amino acid solution via central venous catheterization and 10% lipid solution via peripheral venous lines has been applied to the postoperative patients with esophageal cancers since 10 years ago. sixty-five percent of the patients who underwent surgical treatment showed abnormal signs of the glucose tolerance function test. Positive application of insulin for these patients was performed according to the algorism of continuous insulin infusion method devised by us. Serum glucose levels have been kept within the normal range during the postoperative days. Non-protein Calorie per nitrogen (Cal/N) was optimal at 190, and 10% of the total Calorie administered should be obtained as lipid solution. Postoperative changes of glucose synthase I and D, and phosphorylase a and b of leukocytes were analysed periodically. Chemiluminescence of leukocytes were also checked. Postoperative combined therapies were actively performed under the nutritional support of TPN. The cases of n (-), n1(+) and n2(+) were treated with radio-chemoimmunotherapy (4000 R, Bleomycin 80 mg, Tegaful 500-750 mg/day, PSK or OK-432). The cases of n3(+) and n4(+) were treated with aggressive chemotherapy (Adriamycin, Mitomycin and Pepleomycin). Remarkable improvement of the prognosis in these patients was obtained.

Animals↗
PubMed1983

An immunohistochemical study of hepatoblastoma producing human chorionic gonadotropin.

High tissue concentrations of human chorionic gonadotropin (hCG) and alpha-fetoprotein (AFP) were revealed by radioimmunoassay in a hepatic tumor which was surgically removed from a two-year, eight-month-old boy manifesting sexual precocity. Histologically the tumor showed an embryonal type hepatoblastoma admixed with multinucleated tumor giant cells. The localization of native hCG and hCG-beta subunit was immunohistochemically demonstrated in some of the above giant cells, while that of alpha-fetoprotein was diffusely in the tumor cells of hepatoblastoma of embryonal type. Ultrastructural features of the giant cells were also presented.

Carcinoma, Hepatocellular↗
PubMed1983

A new method of vesicle formation by salting-out and its application to the reconstitution of sarcoplasmic reticulum.

This paper describes a new method of forming membrane vesicles. It was found that the addition of salt such as KCl into a solution containing lipid (asolectin) and a non-ionic surfactant, Triton X-114, led to the formation of closed membrane vesicles. The vesicles were separated from Triton X-114 by hydrophobic interaction chromatography. Electron microscopy revealed that the mean diameter of the vesicles was 110 nm +/- 69 nm (S.D.). Measurement of osmotic volume change showed that the permeability of the vesicle was very low to salts, sugar (glucose) and amphoteric ion (glycine), but very high to glycerol, ethylene glycol and water. Vesicle formation by this 'salting-out' method is very useful for reconstitution of transport systems in biomembranes because of its advantages: completion within a short time; high yield; and the possibility of utilizing samples in non-ionic surfactant solution. When we applied the method to the reconstitution of sarcoplasmic reticulum, Ca2+-ATPase was incorporated into the reconstituted vesicles and was enzymatically active in the membrane.

Animals↗
PubMed1983

Advances in treatment of biliary atresia.

During 29 years from 1953 through 1981, 224 patients with congenital biliary atresia were treated and 200 of them underwent corrective operation at the Second Department of Surgery, Tohoku University Hospital. With the advance of surgical techniques and early diagnosis of biliary atresia, the rate of jaundice disappearance improved from the initial 15 per cent to the recent 69 per cent. Important factors contributing to the improvement of operative results included (1) an early operation, preferably within 60 days after birth, (2) a precise dissection and adequate transection of the porta hepatis, (3) prevention of post-operative cholangitis and (4) reoperation if indicated. Delayed operation and occurrence of post-operative cholangitis affected not only immediate but also long term operative results. Although, nearly all the patients with biliary atresia had portal hypertension at the time of surgery, the portal vein pressure decreased after successful operation, mainly due to improvement in portal venous circulation of the liver. It is considered from recent operative results that more than 80 per cent of patients with biliary atresia can be cured when an adequate corrective operation is carried out before 60 days of age and post-operative cholangitis is prevented.

Bile Ducts↗
PubMed1983

NK cell activity in pulmonary tuberculosis.

Natural killer (NK) cell activity, which may provide defence mechanism in the immune surveillance system, was studied in 38 patients with active pulmonary tuberculosis and 54 sex-, and age-matched healthy controls. The mean NK cell activity in patients with active pulmonary tuberculosis (58.7 +/- 26.4%) was significantly higher (P less than 0.001) than that in healthy controls (17.4 +/- 12.2%). Classifying the patients into three groups according to the state of excretion of tubercle bacilli, the mean NK cell activity in newly diagnosed patients was 43.2 +/- 20.7%, in advanced disease 59.4 +/- 30.3%, and in successfully treated patients 71.9 +/- 25.9%.

Adult↗
PubMed1983

Fast release of calcium from sarcoplasmic reticulum vesicles monitored by chlortetracycline fluorescence.

Rapid Ca2+ release rate from sarcoplasmic reticulum vesicles was determined by the stopped flow method in terms of chlortetracycline fluorescence. Intensity of chlortetracycline fluorescence was proportional to the intravesicular free Ca2+ concentration. Ca2+ efflux was activated by extravesicular Ca2+ with an apparent dissociation constant of 25 microM and was inhibited with an inhibition constant of 120 microM in the absence of Mg2+. Caffeine enhanced the Ca2+ release rate by increasing only the affinity of Ca2+ for the activation site. Mg2+ reduced the Ca2+ release rate by competitive binding to the activation site. ATP increased the Ca2+ release rate very much without changing the affinities of Ca2+ for the activation and inhibition sites, i.e., ATP seems to increase the pore radius or number of the Ca2+ channels without affecting the gating mechanism of the channel. These results are consistent with those reported in skinned muscle sarcoplasmic reticulum. The maximum rate of Ca2+ release in the presence of ATP reached 80 s-1. This value is considered to be sufficient to cause muscular contraction.

Adenosine Triphosphate↗