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Biomedical subjects

K Tsukada

Publications and source records attributed to K Tsukada.

At least 127 records · Page 7Linked to original sources
PubMed1996

Distribution of phosphoneuroprotein 14 (PNP 14) in vertebrates: its levels as determined by enzyme immunoassay.

We have established an enzyme immunoassay for phosphoneuroprotein 14 (PNP 14) which is mainly localized in the cytoplasmic matrix in presynaptic axon terminals and which is phosphorylated in vivo, as well as in vitro. Fab' prepared from rabbit IgG antibodies against bovine PNP 14 was conjugated with maleimide-horseradish peroxidase. The enzyme-conjugated Fab' was used as a second antibody in a sandwich enzyme immunoassay. This assay was able accurately to quantify 0.5-100 ng of rat PNP 14, as well as bovine PNP 14, and it was used for the determination of concentrations of PNP 14 in various rat tissues, neuroblastoma cells, and brains of other vertebrates. The concentrations of PNP 14 in the rat cerebrum, cerebellum, and testis were 1.1, 1.0, and 0.28 micrograms/mg of protein, respectively, and those in other tissues examined were less than 0.1 microgram/mg of protein. PNP 14 was also found in cultured cells, such as rat pheochromocytoma PC12 cells, NG108-15 cells, which are a hybrid between a mouse neuroblastoma and a rat glioma, mouse neuroblastoma Neuro-2a cells, and human neuroblastoma IMR32 cells. Furthermore, PNP 14-specific immunoreactivity was evaluated in the brains of various vertebrates, such as fish, frog, snake and chicken by immunoblot and enzyme immunoassay. The results revealed the immunoreactivity in the brains of all vertebrates examined and the levels were determined to be 0.6-2.1 micrograms bovine PNP 14 equivalents per mg of protein, suggesting that PNP 14 might be an essential component of the central nervous systems of vertebrates.

Animals↗
PubMed1996

CPP32/Yama/apopain cleaves the catalytic component of DNA-dependent protein kinase in the holoenzyme.

DNA-dependent protein kinase (DNA-PK) is composed of a 460-kDa catalytic component (p460) and a DNA-binding component Ku protein. Immunoblot analysis after treatment of Jurkat cells with anti-Fas antibody demonstrated the cleavage of p460 concomitantly with an increase in CPP32/Yama/apopain activity. Recombinant CPP32/Yama/apopain specifically cleaved p460 in the DNA-PK preparation that had been purified from Raji cells into 230- and 160-kDa polypeptides, the latter of which was detected in anti-Fas-treated Jurkat cells. The regulatory component Ku protein was not significantly affected by CPP32/Yama/apopain. DNA-PK activity was decreased with the disappearance of p460 in the incubation of DNA-PK with CPP32/Yama/apopain. These results suggest that the catalytic component of DNA-PK is one of the target proteins for CPP32/Yama/apopain in Fas-mediated apoptosis.

Amino Acid Sequence↗
PubMed1996

Enhancing effects of vasoconstrictors on bile flow and bile acid excretion in the isolated perfused rat liver.

The effects of vasoconstrictors on bile flow and bile acid excretion were examined in single-pass isolated perfused rat livers. Administration of norepinephrine (NE), 4 nmol/min, plus continuous infusion of taurocholate (TC) (1.0 mumol/min) rapidly increased bile flow in 1 min, and from min 5 until the end of NE administration (late period) bile flow remained above the basal level (111.7 +/- 2.2%), as did bile acid output (114.6 +/- 1.8%). Without TC infusion, administration of NE produced no increase in the late period. Administration of NE plus taurochenodeoxycholate (1.0 mumol/min) increased bile flow and bile acid output in the late period to 121.9 +/- 7.0 and 137.1 +/- 6.8%, respectively. With NE plus taurodehydrocholate, the respective values were only 105.4 +/- 1.6 and 104.1 +/- 4.0%. When horseradish peroxidase (HRP) (25 mg) was infused over 1 min with continuous NE, the late peak (20-25 min) of HRP elimination into bile significantly exceeded that of untreated controls (P < 0.01). These observations suggest that vasoconstrictors enhance biliary excretion of more hydrophobic bile acids, in part by stimulating vesicular transport.

Animals↗
PubMed1996

Suppression of hepatic portal blood flow caused by carbon dioxide pneumoperitoneum can be restored after dopamine administration in pigs.

Portal venous blood flow (PVF), hepatic arterial blood flow (HAF) and systemic arterial pressure (SAP) were examined after dopamine (DA) injection into the jugular vein under carbon dioxide pneumoperitoneum in pigs. When intraabdominal pressure (IAP) was increased by 12 mmHg, PVF and HAF were reduced, but SAP was unchanged. When IAP was kept at 12 mmHg, the injection of DA at 10 micrograms/kg/min for 2 min produced an increase in PVF without causing any change in HAF or SAP. The response in PVF was dose-dependent. When IAP was increased to 16 mmHg, PVF response was diminished, and no change in HAF or SAP was seen at the same dose of DA. These observations suggest that DA is effective in increasing PVF under enhanced IAP conditions, but such circulatory improvement due to the agent would be prominent when IAP is below 12 mmHg.

Animals↗
PubMed1996

Colorectal carcinoma metastases to the liver. Does primary tumor location affect its lobar distribution?

BACKGROUND: There is considerable evidence that blood returning from different abdominal organs does not mix completely but maintains streamline flow in the portal vein. This study tested the hypothesis that the location of primary colorectal carcinoma affects the intrahepatic distribution of liver metastases according to streamline flow in the portal vein. METHODS: Eighty-five patients with histologically verified liver metastases from colorectal carcinoma underwent potentially curative hepatectomy. Primary tumor location was the right-sided colon in 18 patients and the left-sided colon in 67. The liver was divided into two lobes by Cantlie's line. RESULTS: A total of 195 metastatic deposits were resected: 135 in the right lobe and 60 in the left. In the right-sided colon carcinoma group, 29 deposits were in the right lobe and 3 in the left. In the left-sided colon carcinoma group, 106 deposits were in the right lobe and 57 in the left. The pattern of lobar distribution was significantly different in the two groups (P = 0.003). CONCLUSIONS: Right-sided colon cancers selectively involve the right lobe, while left-sided tumors involve the entire liver, considering the ratio of weights of the right to left lobe is 2:1. This difference suggests that primary tumor location affects the pattern of lobar distribution of colorectal carcinoma liver metastases according to streamline flow in the portal vein.

Carcinoma↗
PubMed1996

Characterization of DNA ligase from the fungus Coprinus cinereus.

DNA ligase was highly purified from the fungus Coprinus cinereus at the miotic recombination stage, pachytene. The pachytene DNA ligase showed three polypeptides with molecular masses of 88, 84 and 80 kDa, as estimated by the [32P]AMP-labeling assay. These three polypeptides were susceptible to reaction with an mAb against a 16-amino-acid sequence in human DNA ligase I, which is conserved in C-terminal regions of mammalian, vaccinia virus and yeast DNA ligases. Since rapidly purified preparations from fresh pachytene cells exhibited a single polypeptide of DNA ligase with a molecular mass of 88 kDa, the smaller polypeptides seemed to be limited-degradation products of the 88-kDa polypeptide during the isolation and purification procedures. K(m) values for ATP and (dT)20 hybridized with (dA)n were 1.5 microM and 90 nM, respectively. This enzyme was capable of joining (dT)20.(rA)n and (rA)12-18 (dT)n as well as (dT)20.(dA)n and able to ligate blunt-ended DNA in the presence of poly(ethylene glycol) 6000. DNA ligases were also partially purified from zygotene cells at the meiotic pairing stage and mitotic mycelium cells. In their molecular mass, immuno-reactivity, K(m) value and substrate specificity, they were indistinguishable from pachytene DNA ligase. These results suggest that the fungus C. cinereus at the pachytene stage contains DNA ligase with a molecular mass of 88 kDa as a main or a single species, which is quite similar to DNA ligases from the zygotene and mycelium cells in molecular and catalytic properties.

Amino Acid Sequence↗
PubMed1996

Reversible G1 arrest induced by dimethyl sulfoxide in human lymphoid cell lines: dimethyl sulfoxide inhibits IL-6-induced differentiation of SKW6-CL4 into IgM-secreting plasma cells.

We have previously found that dimethyl sulfoxide (DMSO), a known inducer of differentiation in several kinds of myeloid cells, arrests proliferation of human lymphoid cells including Raji and Akata Burkitt's lymphoma cells at the G1 phase. We investigated whether DMSO affects cell proliferation and differentiation of the lymphoid cell line SKW6-CL4, which is capable of differentiating terminally into IgM-producing cells. As in the case of Raji, Akata, and Molt-4, the proliferation of SKW6-CL4 was reversibly arrested at the G1 phase by treatment with 2% DMSO for 5 days even in the presence of interleukin-6 (IL-6). DMSO inhibited spontaneous IgM secretion as well as IL-6-induced IgM production in SKW6-CL4 at a concentration lower than that affecting cell proliferation. Of the cell-surface differentiation markers CD10, CD20, CD21, and CD23, the expression of CD20 was suppressed by DMSO treatment, and partial restoration of the expression was observed 24 to 48 h after release from DMSO. The level of IL-6 receptor protein was not affected by DMSO treatment. These results indicate that DMSO not only arrests the cell cycle of a human lymphoid cell line SKW6-CL4 at the G1 phase but also inhibits the differentiation into IgM-secreting cells at a concentration lower than that affecting cell proliferation and that DMSO overcomes the effect of IL-6 on terminal differentiation of SKW6-CL4. As a whole, proliferation of human lymphoblastoid cell lines was revealed to be reversibly arrested at the G1 phase by DMSO, which is known to induce differentiation in several myeloid cells, without inducing cell differentiation.

Antigens, CD↗
PubMed1996

Carcinoma of the ampulla of Vater: is radical lymphadenectomy beneficial to patients with nodal disease?

This study was undertaken to evaluate the effectiveness of radical lymphadenectomy in ampullary cancer with nodal disease. Thirty-five patients underwent the Whipple procedure with radical lymphadenectomy. The location and number of positive nodes was characterized. Eighteen patients (51%) had positive nodes. Patients without nodal disease (pN0 group) had an actuarial 5-year survival rate of 81%. Seven patients with metastasis confined to the pancreaticoduodenal nodes had a 5-year survival rate of 67%, which was comparable for the pN0 group (N.S.) and better than the 27% 5-year survival rate in patients with positive superior mesenteric nodes (P<0.05). Eleven patients with one to three positive nodes had a 5-year survival rate of 71%, which was also comparable to the pN0 group (N.S.) and better than the 0% 5-year survival rate in patients with four or more positive nodes (P<0.01). Radical lymphadenectomy is effective against a limited degree of nodal disease.

Actuarial Analysis↗
PubMed1996

Indocyanine green disappearance enhanced by prostaglandin E1 in patients with hepatic resection.

Indocyanine green (ICG) is a reliable indicator reflecting hepatocyte function and hepatic blood flow. Prostaglandin E1 (PGE) has been indicated to increase hepatic blood flow and protect the hepatocyte. The purpose of this study is to investigate whether PGE influences the ICG disappearance rate in patients with hepatic resection. Eleven patients with hepatic resection were divided into two groups according to the presence of liver cirrhosis (LC, n = 4) and chronic hepatitis (CH, n = 7). ICG 0.1 mg/kg was given as an intravenous bolus into the cubital vein 5 min after PGE administration, then the disappearance rate of ICG (ICG-K) was determined by a finger monitoring method. PGE administration increased ICG-K in the LC and CH groups with normal liver function, and the ICG-K response was dose dependent when the dosage of PGE ranged from 0.01 to 0.05 microg/kg/min. When ICG-K relative to the ICG-K of the control was defined as the ICG-K ratio, the daily course of the ratio in the LC group was higher than in the CH group. PGE increases the ICG-K of patients with normal liver function before and after hepatic resection, and this is evident in the case of liver cirrhosis.

Aged↗
PubMed1996

Enhancement of portal blood flow by ursodesoxycholic acid in partially hepatectomized rats.

Portal venous flow (PVF) was examined after portal injection of ursodesoxycholic acid (URSO) in rats that were partially hepatectomized by either 40% or 66%. URSO (10 mg/kg per minute) was injected into the portal vein and was thereafter observed to increase PVF concomitantly with a fall in portal vein and was thereafter observed to increase PVF concomitantly with a fall in portal venous pressure (PVP) in control animals. The increase in PVF in response to URSO was dose-dependent. In hepatectomized rats, the PVF response was augmented when the same dose of URSO was portally injected, and the magnitude of response was enhanced in proportion to the volume of liver resected. These results suggest that URSO increases PVF through vasodilation of the portal vessels, and therefore URSO is considered to increase PVF potently in a partially hepatectomized condition.

Animals↗
PubMed1996

Hepatocellular carcinoma associated with precirrhotic primary biliary cirrhosis successfully treated by a right hepatic lobectomy: report of a case.

We report herein the case of a 69-year-old woman in whom hepatocellular carcinoma (HCC) arising in the precirrhotic phase of primary biliary cirrhosis (PBC) was successfully managed by a right hepatic lobectomy. The patient, who had never received a blood transfusion, had a 4-year history of asymptomatic PBC of Scheuer's histological classification stage II. Abdominal computed tomography (CT) revealed a mass measuring 4.0 cm in the right hepatic lobe, and a right hepatic lobectomy was performed in consideration of her good liver function and the deep location of the tumor in the right lobe. The patient has remained well without any evidence of recurrent disease for 4 years since her operation. A review of the literature revealed only two cases of successful partial hepatectomy, but none of major hepatectomy. Most of the reported cases had been treated with transcatheter arterial embolization (TAE) and were associated with poor survival. Our experience of this patient indicates the potential value of hepatectomy as an alternative to TAE in selected patients with resectable disease and good hepatic function.

Aged↗
PubMed1996

Effect of prostaglandin E1 on ammonia concentration in blood of patients with hepatic resection.

Plasma concentrations of ammonia were examined following prostaglandin E1 (PGE1) administration in 16 patients who received hepatectomy for hepatocellular carcinoma. PGE1 at 0.01-0.04 microgram/kg/min was administered for approximately 24 hr during the perioperative periods. The ammonia concentration was reduced a day after the operation following intravenous administration of PGE1 in cirrhotic patients compared to noncirrhotic patients with or without PGE1 injection. Serum liver function scores, glutamic pyruvic transaminase, and total bilirubin concentrations were decreased after PGE1 administration. A similar ammonia response due to PGE1 was obtained after operation in cirrhotic patient when PGE1 0.5 microgram/kg was administered intravenously for 30 min. These results suggest that PGE1 administration is useful in reducing the enhanced ammonia concentration associated with hepatic resection, and it is particularly effective in the case of liver cirrhosis.

Alanine Transaminase↗
PubMed1996

The mode of lymphatic spread in carcinoma of the bile duct.

BACKGROUND: Knowing the prevalence of lymph node involvement associated with the location of the primary tumor is a prerequisite for operating with curative intent in carcinoma of the bile duct. METHODS: We evaluated 80 patients with carcinoma of the bile duct or cystic duct to investigate the frequency of lymph node involvement, the mode of lymphatic spread, and prognosis, according to the location of the primary tumor. RESULTS: The frequency of lymphatic spread of carcinomas in the proximal, middle, and distal bile ducts, excluding seven T1 tumors, was 48%, 67%, and 56%, respectively. With regard to the mode of lymphatic spread: (1) a metastatic pathway along the common hepatic artery predominated over that to the retropancreatic area in the proximal duct carcinoma group; (2) in the middle duct carcinoma group, metastatic lymph nodes were distributed widely, involving nodes around the superior mesenteric artery or at the para-aortic area; and (3) in the distal duct carcinoma group, metastatic nodes generally were localized around the head of the pancreas. CONCLUSIONS: Understanding the mode of the lymphatic spread according to the primary tumor may be helpful for choosing the appropriate surgical approach with curative intent in bile duct carcinoma.

Adult↗
PubMed1996

Outcome of radical surgery for carcinoma of the gallbladder according to the TNM stage.

BACKGROUND: The role of surgery in the treatment of gallbladder carcinoma (GBC) is controversial. The outcome after prospective radical surgery for GBC is discussed on the basis of the TNM stage of the tumor. METHODS: One hundred six patients who had undergone radical surgery were selected. The standard radical procedure consisted of a cholecystectomy accompanied by lymph node dissection, wedge resection of the liver, and resection of the extrahepatic bile ducts. The stage was determined by pathologic examination of resected specimens. RESULTS: Lymph node metastases were identified in no patients with T1 tumors (n = 15), 48% of patients with T2 tumors (n = 46), 72% of patients with T3 tumors (n = 25), and 80% of patients with T4 tumors (n = 20). One patient died within 30 days after radical surgery (mortality rate, 0.9%). There were 35 5-year survivors including 11 patients with nodal involvement, 10 with stage I tumors, 13 with stage II tumors, 10 with stage III tumors, and 2 with stage IV tumors. The cumulative 5-year survival rate in patients with stage I tumors was 91% (n = 15), 85% in patients with stage II tumors (n = 24), 40% in patients with stage III tumors (n = 28), and 19% in patients with stage IV tumors (n = 39). In patients with stage III and IV tumors the 5-year survival rate was 52% after curative resection (n = 35). This was significantly better than the 5% 5-year survival rate after a noncurative resection (n = 32). CONCLUSIONS: The presence of lymph node metastases is strongly influenced by the depth of invasion of the primary tumor. Accurate determination of the TNM stage is essential in comparing surgical results, predicting patient outcome, and planning additional treatment. Standard radical surgery contributes to patient survival and is recommended in patients with advanced GBC.

Adult↗
PubMed1996

Expression of S-adenosylmethionine synthetase isozyme genes in regenerating rat liver after partial hepatectomy.

Mammalian S-adenosylmethionine (AdoMet) synthetase exists as two isozymes, liver-type and non-hepatic-type enzymes. To investigate the possible role of AdoMet synthetase in proliferating cells, we have examined the expression of these two isozyme genes in regenerating rat liver after partial hepatectomy using Northern blot analysis. In normal adult rat liver the non-hepatic-type isozyme mRNA was not detectable, however, when partial hepatectomy was performed, there was an obvious appearance of the non-hepatic-type enzyme mRNA after operation. The levels of non-hepatic-type isozyme mRNA was peaked at 4h and maintained the level at least till 8 h after operation, then decreased. In addition, the liver-type AdoMet synthetase gene expression was also induced by partial hepatectomy with similar time course. These results indicate that these two AdoMet synthetase isozymes may play an important role during the prereplicative phase which precedes DNA synthesis.

Animals↗
PubMed1996

Reconstruction of two-dimensional current distribution from tangential MCG measurement.

We describe a two-dimensional reconstruction method for tangential magnetocardiograms (MCGs). This method is based on two-dimensional Fourier analysis, and we used a new type of window function for tangential MCG to solve the problem of the small number of measurement points. By using this method, cardiac activity can be estimated as a two-dimensional current distribution. To determine the effectiveness of this method, we measured tangential MCGs of normal subjects, and compared the estimated current distribution with the actual cardiac muscle activity. Using this method, we were able to clearly show cardiac activity.

Adult↗
PubMed1996

Neovascularization of the corpus luteum of rats during the estrus cycle.

In order to elucidate the chronological morphological changes of the corpus luteum (CL) of rats, as a physiological angiogenesis model, the CL of rat ovaries was studied light microscopically using periodic acid methenamine silver staining (PAM) and immunostaining for type IV collagen, laminin, thrombomodulin (TM), factor VIII related antigen (factor VIII) and alpha-smooth muscle actin (alpha-SMA). The CL was also studied electron microscopically. Female Wistar-Imamichi rats were used, which have a regular 4-day estrous cycle. The histological changes of the CL were observed in 6-hour intervals from 4 h before the ovulation to 28 h post-ovulation during the estrous cycle. Once the basement membrane (BM) of the follicle disintegrated following ovulation, developing capillaries entered into the CL and formed a vascular lumen with a surrounding BM, which showed positive for PAM staining, type IV collagen and laminin. The developing capillaries in the CL showed a weakly positive reaction for TM and factor VIII, but were negative for alpha-SMA. However, the appearance of immature pericytes around the well-developed capillary was obvious with electron microscopy. The study reported here provides detailed descriptions of angiogenesis during luteinization. It is concluded that the angiogenesis of the CL begins at the time of destruction of the BM of the ovarian follicle, and that the capillary BM appears when the capillary forms its lumen. Moreover, it was demonstrated that the capillary does not develop into an arteriole during luteinization.

Animals↗