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Biomedical subjects

K Takase

Publications and source records attributed to K Takase.

At least 91 records · Page 5Linked to original sources
PubMed2000

Serological monitoring on layer farms with specific pathogen-free chickens.

To monitor the existence of avian pathogens in laying chicken flocks, specific pathogen-free (SPF) chickens were introduced into two layer farms and reared with laying hens for 12 months. SPF chickens were bled several times after their introduction and examined for their sero-conversion to avian pathogens. As a result, antibodies to eight or ten kinds of pathogens were detected in SPF chickens on each farm. Antibodies to infectious bronchitis virus (IBV), avian nephritis virus, Mycoplasma gallisepticum and M. synoviae were detected early within the first month. Antibody titer to IBV suggested that the laying chickens were infected with IBV repeatedly during the experiment on both farms. However, antibodies to infectious bursal disease virus and 6 pathogens were not detected.

Animals↗
PubMed2000

Evaluation of intracranial pressure by transcranial Doppler ultrasonography in dogs with intracranial hypertension.

Transcranial Doppler ultrasonography (TCD) has been used to confirm changes in cerebral hemodynamics. In this study, we investigated whether the parameters for the basilar artery measured by TCD were correlated with the intracranial and cerebral perfusion pressures in extreme intracranial hypertension. An intracranial hypertension model was produced in seven dogs by inflating a balloon inserted into the epidural space. The resistance index was compared with the corresponding intracranial pressure and cerebral perfusion pressure values during intracranial hypertension. A significant correlation was recognized between the resistance index and cerebral perfusion pressure. Therefore, measurement of the basilar artery by TCD in the dog with intracranial hypertension is useful in estimating the intracranial circulation in cases where the measurement of intracranial pressure is not available or not indicated.

Animals↗
PubMed2000

Polyhydroxybutyrate production from carbon dioxide by cyanobacteria.

Genetic characterization and enhancement of polyhydroxybutyrate (PHB) accumulation in cyanobacteria were investigated for efficient PHB production from CO2. The genome DNAs in the PHB-accumulating strains Synechococcus sp. MA19 and Spirulina platensis NIES46 retained the highly homologous region to phaC of Synechocystis PCC6803, whereas low homology was detected in the nonaccumulating strains Synechococcus sp. PCC7942 and Anabaena cylindrica NIES19. Synechococcus sp. MA19, which accumulates PHB up to 30% of dry cell weight from CO2 as the sole carbon source, was mutated by insertion of transposon Tn5 to enhance the PHB accumulation. Genetic and physiological analysis of the mutant indicated that decreased phosphotransacetylase activity could trigger an increase of acetyl coenzyme A leading to enhancement of PHB accumulation. PHB synthase in Synechococcus sp. MA19 was probably attached to thylakoid membrane since PHB granules were associated with pigments. A genetically engineered cyanobacteria retaining soluble PHB synthase from Ralstonia eutropha accumulated pigment-free PHB granules, which is an advantage for the purification of PHB.

Acyltransferases↗
PubMed2000

Relationship between the pixel value in digital subtraction angiography and iodine concentration: study in high iodine concentration with original phantom.

Quantitative digital subtraction angiography (DSA) image analysis based on densitometry is widely accepted and used. For the densitometoric DSA image analysis, it is required that there is a linear relationships between the pixel values on DSA images (DSA values) and contrast medium iodine concentration or the thickness of the vessels or the chambers filled with contrast material. We studied on relationship between the DSA value and iodine concentration especially in high iodine concentration. As for the relationship between DSA values and iodine concentration on the DSA images at low concentration, DSA phantom had a good linear relationship. However, the relationship at the high iodine concentration, DSA phantom sometimes lost this linear relationship. Our results suggested that it was necessary to identify relationship between DSA values and iodine concentration in each DSA system, especially in high iodine concentration setting, for densitometoric DSA image analysis.

Angiography↗
PubMed2000

Effect of segmental transcatheter arterial chemoembolization on branched chain amino acids and tyrosine ratio in patients with hepatocellular carcinoma.

The effect of segmental transcatheter arterial chemoembolization (TAE) on serum amino acid levels and liver function were studied in 23 patients with HCC associated with hepatitis virus C (22 patients) or alcoholism (1 patient), with compensated liver cirrhosis (Child A 18 patients, Child B 5 patients). Serum levels of branched-chain amino acids (BCAA), tyrosine, branched-chain amino acids to tyrosine ratio (BTR), ammonia, total bilirubin and albumin, and prothrombin times were measured before and after TAE (24 h, 7 and 14 days). The BTR was increased significantly 24 h after TAE (p<0.001) and gradually decreased to pre-TAE levels. Serum tyrosine levels decreased at 24 h after TAE (p<0.005) and later increased. Serum BCAA levels increased slightly at 7days after TAE and were decreased at 14 days after TAE. This results indicated that the increased BTR was due primarily to the decreased tyrosine level at 24 h after TAE. Serum ammonia levels gradually decreased after TAE and the prothrombin time and serum levels of total bilirubin and albumin were not significantly changed. In this study, segmental TAE had little influence on liver function, and the BTR unexpectedly increased at 24 h after TAE. These results suggest that segmental TAE has minimal side effects and may have a beneficial effect on amino acid metabolism.

Adult↗
PubMed2000

[Renal cell carcinoma in a horseshoe kidney with abdominal aortic aneurysm: a case report].

We herein report a case of renal cell carcinoma in a horseshoe kidney with an abdominal aortic aneurysm in a 69-year-old man. Radiological examinations showed a left renal tumor, horseshoe kidney and abdominal aortic aneurysm. We performed a left radical nephrectomy with the division of the isthmus and artificial graft through an abdominal transperitoneal approach. Histological findings revealed clear cell type renal cell carcinoma without invasion of the capsule or renal pelvis. Only 31 cases of renal cell carcinoma in a horseshoe kidney have been reported in Japan, and our case is the 32nd. No case with abdominal aortic aneurysm has been reported previously. We assume that abdominal aortic aneurysm was associated with renal cell carcinoma by chance in the horseshoe kidney in this case. The arterial and venous supplies vary from case to case. We emphasize that arteriography and venography are very important preoperative procedures.

Aged↗
PubMed2000

[An autopsy case of thymic carcinoma producing various tumor markers and the examination of 222 autopsy cases of thymic malignant tumor in Japan].

The autopsy of a 76-year-old Japanese female patient, which revealed thymic carcinoma with various tumor markers such as NSE, CYFRA, and CA-125, is presented. The patient died from hepatic failure because the liver was overtaken by the tumors. At autopsy, the thymic carcinoma was found to have metastased only in the liver. From microscopical analyses and electron microscopical findings, we diagnosed poorly differenciated squamous cell carcinoma of thymic origin. In the histochemical analyses, the tumor cells were positively stained in CA 125, CA 19-9, EMA, NSE, AE 1, AE 3, CEA, S-100, glimerius and Bcl-2. These date suggest that the tumor cells produced various tumor markers. In 222 autopsy cases of thymic malignant tumor observed in Japan over a period of 4 years, the dominant pathohistological image was squamous cell carcinoma. It is interesting that the greatest number of combined malignant tumors with thymic malignancies were thyroid papillary carcinomas.

Aged↗
PubMed2000

[An autopsy case of chronic thromboembolic pulmonary hypertension with long-term progressive dyspnea].

A 71-year-old man who had been suffering from slowly progressive dyspnea on exertion for 16 years was admitted because of hemoptysis and severe dyspnea in 1997. His medical history included respiratory failure in 1986. At that time, chest X-ray films showed cardiomegaly and striking enlargement of hilar pulmonary arteries, while a lung perfusion scan revealed segmental defects. A diagnosis of chronic thromboembolic pulmonary hypertension (CTPH) was made on the basis of multiple filling defects detected by pulmonary angiography and marked pulmonary hypertension (104/29 mmHg) measured by right heart catheterization. The patient died unexpectedly 1 month later. Autopsy revealed a large new thrombotic lesion straddling the organizing thrombotic lesion in the right pulmonary artery. It is important to keep CTPH in mind when examining and treating patients with unexplained dyspnea. In this respect, our case was considered of value to an understanding of the natural course of CTPH.

Aged↗
PubMed2000

Clinico-epidemiology of hepatitis B viral infection in Northeastern Thailand.

Hepatitis B viral (HBV) infection is a common disease world wide. A study of clinico-epidemiology of HBV infection was conducted in 381 patients who seropositive for hepatitis B surface antigen (HBsAg) in Srinagarind Hospital, Khon Kaen University, Northeastern Thailand, during August 1997 to December 1998. 293 males, 88 females and their mean age was 30.96 +/- 12.78 years with a range from 15 to 77 years. The clinical features of acute hepatitis, chronic hepatitis, liver cirrhosis, hepatocellular carcinoma (HCC) and asymptomatic carrier were 2.36, 34.12, 4.99, 1.05 and 57.48% of cases. Possible routes for HBV transmission were family history of hepatitis, tattooing, intravenous drug addict and blood transfusion in 20.3, 11.3, 8.2 and 6.9% of cases, respectively. Signs of chronic liver disease were common in liver cirrhosis and HCC. Acute fulminating hepatitis was not found in this study.

Adolescent↗
PubMed2000

Clinico-epidemiology of hepatitis C viral infection in northeastern Thailand.

Hepatitis C virus (HCV) is responsible for a large number of cases of chronic liver disease worldwide. A study of clinico-epidemiology of HCV infection was conducted in 214 patients who were seropositive for antibody to HCV (anti-HCV) in Srinagarind Hospital, Khon Kaen University, northeastern Thailand, during August 1997 to December 1998. There were 199 males, 15 females and their mean age was 34.96 +/- 9.75 years with a range from 16 to 72 years. The clinical features of acute hepatitis, chronic hepatitis, liver cirrhosis, hepatocellular carcinoma (HCC) and asymptomatic HCV infection were 2, 115, 15, 2 and 80 cases. Risk factors for HCV acquisition were intravenous drug use (IVDU), tattooing and blood transfusion in 46.7, 32.2 and 18.8% of cases, respectively. 23.36% had a history of multiple risk factors while 28.9% had no history of risk factor exposure.

Adolescent↗
PubMed1999

Enterococcus hirae vacuolar ATPase is expressed in response to pH as well as sodium.

The Enterococcus hirae ntp operon encodes both a vacuolar ATPase, which transports Na+ as well as Li+, and the KtrII K+ transporter. A plasmid, in which the chloramphenicol acetyltransferase gene (CAT) was placed downstream of the ntp promoter, was introduced into a mutant totally defective in Na+ extrusion. The CAT activity of this transformant was increased preferentially by addition of NaCl, but not by LiCl, in the media or by elevating the medium pH, correlating well with the increase in amounts of the ATPase subunits observed by Western blotting. The physiological significance of these responses of the ntp promoter is discussed.

Chloramphenicol O-Acetyltransferase↗
PubMed1999

Expression of functional CD40 in human hepatocellular carcinoma.

CD40, a member of the tumor necrosis factor receptor (TNFR) family, plays a crucial role in the survival, proliferation, and differentiation in B cells. However, the expression of CD40 other than in B cells has not been well studied. Therefore, we investigated the expression and function of CD40 in hepatocellular carcinomas (HCCs). Expression of CD40 mRNA in 6 established HCC cell lines was analyzed by reverse-transcription polymerase chain reaction (RT-PCR) and CD40 expression on cell surface was examined by flow cytometrical analysis. We also examined the expression of CD40 in human HCC tissues (45 cases) and nontumor liver tissues (30 cases) by immunohistochemistry. To examine the function of CD40 in HCC cells, we investigated the effect of CD40 signaling on anti-Fas antibody and TNF-alpha-induced apoptosis in HepG2 cells. In addition, intracellular levels of cysteine protease P32 (CPP32) protein in HepG2 cells were also determined by Western blotting. We have shown that 6 HCC cell lines constitutively expressed CD40 mRNA and membrane-bound CD40 antigen, which was slightly up-regulated by interferon gamma (IFN-gamma). In addition, 60% of human HCC tissues demonstrated positive staining for CD40, whereas nontumor tissues showed little detectable staining. In HepG2 cells, CD40 stimulation does not affect cell viability, but significantly inhibited Fas and TNFR-mediated apoptosis in a dose-dependent manner by blocking the activation of CPP32. From these results, we conclude that CD40 expression in HCCs plays an important role in tumor biology, especially the resistance against Fas and TNFR-mediated apoptosis.

Apoptosis↗
PubMed1999

Clinical efficacy of portal vein stent placement in patients with hepatocellular carcinoma invading the main portal vein.

BACKGROUND/AIMS: Hepatocellular carcinoma frequently invades the portal veins, and when it invades the main portal vein, the patient's prognosis is extremely poor. This study was undertaken to evaluate the clinical efficacy of stent placement into the portal vein in these patients. METHODS: Twenty-one patients with hepatocellular carcinoma invading the main portal vein were studied. Stents were placed in the portal veins to compress tumor thrombi after percutaneous transhepatic portography. RESULTS: Stents were successfully placed in the portal veins in all patients. Portal venous pressure significantly decreased from 25.3 +/- 7.4 mmHg to 22.4 +/- 6.6 mmHg (p < 0.0001) immediately after stent placement, leading to improvement in gastroesophageal varices, melena and ascites. Although a pseudoaneurysm of the hepatic artery related to portal vein puncture developed in one patient, there were no major complications in the other 20 patients. Blood flow through the stent was maintained during the survival period in 15 patients. The mean stent patency period was 12.4 months. Fifteen patients underwent transcatheter arterial chemoembolization without major complications after stent placement. The survival rate was 64.2% at 6 months and 29.2% at 1 and 2 years, respectively. The mean survival period was 13.7 months. CONCLUSION: Stent placement into the portal vein is a relatively safe and feasible procedure. It improves portal hypertension, expands treatment options, and helps to prolong the survival period in patients with hepatocellular carcinoma invading the main portal vein.

Aged↗
PubMed1999

Long-term follow-up arterial chemoembolization combined with transportal ethanol injection used to treat hepatocellular carcinoma.

PURPOSE: This study was undertaken to evaluate the long-term efficacy of transcatheter hepatic arterial chemoembolization (TACE) combined with transportal ethanol injection (TPEI) in patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Twenty-six patients with unresectable HCC underwent TPEI 2-6 weeks after TACE. The size of the main tumor ranged from 2.0 to 9.0 cm (mean, 4.5 cm). Ethanol (10-65 mL) was injected via a percutaneous transhepatic approach into the portal vein, perfusing the segment to be treated. TACE was repeated after TPEI in 18 patients. RESULTS: The combined therapy was technically successfully in all 26 cases; however, irreversible hepatic failure developed in two (8%) patients. Recurrent disease occurred either from the treated lesion (four patients) or apart from the treated liver segment (five patients) in nine of 21 patients (43%) followed up for a mean of 34 months. The survival rates were 87%, 72%, 72%, 63%, 51, and 51% at 1, 2, 3, 4, 5, and 6 years, respectively. Resected and autopsied specimens showed complete necrosis in seven of nine main lesions and severe parenchymal damage in the treated liver segment. CONCLUSION: In selected patients, combined treatment with TACE and TPEI is safe and effective, decreasing recurrence rate in the treated segment, and resulting in a 51% 6-year survival.

Aged↗
PubMed1999

Properties of the V0V1 Na+-ATPase from Enterococcus hirae and its V0 moiety.

We report here the large-scale purification of vacuolar (V0V1)-type Na+-ATPase from Enterococcus hirae achieved using column anion-exchange and gel filtration chromatographies; 32 mg of purified enzyme comprising nine subunits, A, B, C, D, E, F, G, I, and K, was obtained from 20 liter culture. This amount is 500-fold larger than that reported in the previous paper [Murata, T., Takase, K., Yamato, I., Igarashi, K., and Kakinuma, Y. (1997) J. Biol. Chem. 272, 24885-24890]. The purified enzyme shows a high specific activity of ATP hydrolysis (35.7 micromol Pi released/min/mg protein). ATP-driven 22Na+ uptake by reconstituted V0V1-proteoliposomes exhibited an apparent Kt value for Na+ of 40 microM, which is near the Km value (20 microM) for Na+ of the ATP hydrolytic activity. Denatured gel electrophoresis revealed that six subunits, A, B, C, D, E, and F, are releasable as the V1 subunit from the V0V1 complex by incubation with ethylenediaminetetraacetic acid; subunit G was not identified. The remaining V0-liposomes containing I and K subunits catalyzed Na+ uptake in response to potassium diffusion potential (Deltapsi, inside negative); the Kt value for Na+ of this reaction was estimated to be about 2 mM. Inhibition by N,N'-dicyclohexylcarbodiimide (DCCD) of the Na+-ATPase activity and Deltapsi-driven Na+ uptake by the V0-liposomes was prevented by the presence of Na+, suggesting that the Na+ binding site overlaps with the DCCD-reactive site.

Dicyclohexylcarbodiimide↗
PubMed1999

Indispensable glutamic acid residue-139 of NtpK proteolipid in the reaction of vacuolar Na(+)-translocating ATPase in Enterococcus hirae.

Enterococcus hirae vacuolar ATPase catalyzes translocation of Na+ or Li+ coupled with ATP hydrolysis. It is suggested that the glutamic acid residue (Glu139) of NtpK proteolipid subunit of this multisubunit enzyme is the binding site of these ions for translocation. Here we established a complementation system for the ntpK gene with its deletion mutant, and found that the ATPase activity disappeared upon replacement of Glu139 by aspartic acid. The side-chain length of this acidic residue of NtpK is thus important for this ATPase reaction.

Adenosine Triphosphatases↗
PubMed1999

The comparison between the cerebral blood flow directly measures and cerebral blood flow velocity in the middle and basilar cerebral arteries measured by transcranial Doppler ultrasonography.

Transcranial Doppler ultrasonography (TCD) may be useful for determining alterations in cerebral blood flow (CBF) during excessive hemodynamic changes by non-invasive measurement of the CBF velocity. The purpose of this study was to measure the correlation between CBF and the middle cerebral artery (MCA) and basilar artery (BA) flow velocities, as measured by TCD during excessive hemodynamic changes produced by hypertension and hypotension in adult dogs. The peak, diastolic, and mean flow velocities were measured by TCD. Arterial hypertension was induced by administration of dopamine at 5 and 15 microg/kg/min, and hypotension was induced by hemorrhage. During the hemodynamic changes, the BA velocity correlated more closely with the alteration in the CBF than the MCA velocity. In terms of percentages of the values during anesthesia, there was good correlation between CBF and the MCA and BA velocities. In conclusion, our findings indicate that MCA and BA velocity measurements, as a percentage of the values during anesthesia, both give an equally accurate indication of alterations in CBF during excessive hemodynamic changes.

Animals↗