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M Ohto

Publications and source records attributed to M Ohto.

At least 19 recordsLinked to original sources
PubMed2001

Effects of sugar on vegetative development and floral transition in Arabidopsis.

Although sugar has been suggested to promote floral transition in many plant species, growth on high concentrations (5% [w/v]) of sucrose (Suc) significantly delayed flowering time, causing an increase in the number of leaves at the time of flowering in Arabidopsis. The effect of high concentrations of Suc seemed to be metabolic rather than osmotic. The delay of floral transition was due to extension of the late vegetative phase, which resulted in a delayed activation of LFY expression. In addition, growth on low concentrations (1% [w/v]) of Suc slightly inhibited flowering in wild-type plants. This delay resulted from effects on the early vegetative phase. This inhibition was more pronounced in tfl1, an early flowering mutant, than in the wild type. Although 1% (w/v) Suc was reported to promote floral transition of late-flowering mutants such as co, fca, and gi, floral transition in these mutants was delayed by a further increase in Suc concentration. These results suggest that sugar may affect floral transition by activating or inhibiting genes that act to control floral transition, depending on the concentration of sugars, the genetic background of the plants, and when the sugar is introduced. Growth on 1% (w/v) Suc did not restore the reduced expression levels of FT and SOC1/AGL20 in co or fca mutants. Rather, expression of FT and SOC1/AGL20 was repressed by 1% (w/v) Suc in wild-type background. The possible effects of sugar on gene expression to promote floral transition are discussed.

Anthocyanins↗
PubMed2000

Quantitative analysis of bowel gas using plain abdominal radiograph in patients with irritable bowel syndrome.

OBJECTIVE: Ideally, the diagnosis of irritable bowel syndrome (IBS) would be achieved using a minimal number of procedures. It is presumed that bowel gas is related to IBS, and it is easily visualized by plain abdominal radiograph. In the present study, to clarify the relationship between IBS and the quantity of bowel gas, the measured bowel gas volume using plain abdominal radiographs was compared with the pathology of IBS. METHODS: Plain abdominal radiographs were digitized and transmitted to a computer (computed radiography) in 30 IBS patients and 30 normal controls. The quantity of bowel gas, determined as the pixel value on images and standardized by physique, was defined as the gas volume score (GVS). Using the mean +/- 2SD of GVS in the control group as the normal score, IBS patients were divided into three groups: high, normal, and low. To examine the sequential reproducibility of a similar quantity of bowel gas, a second plain abdominal radiography was performed about 2 months later, and the GVS were compared. The colonic transit time was determined using radiopaque markers. RESULTS: There was a strong correlation between the quantities of bowel gas measured by two independent gastroenterologists. The mean GVS of IBS patients was significantly higher than that in the control group (p < 0.001). The sequential reproducibility was recognized in all 10 IBS patients. There was no significance between colonic transit time and GVS, nor between symptoms and GVS. CONCLUSIONS: Abdominal gas was analyzed objectively by using GVS, and GVS was considered to represent a useful tool for the diagnosis of IBS.

Adult↗
PubMed2000

Comparison of CT findings with resected specimens after chemoembolization with iodized oil for hepatocellular carcinoma.

OBJECTIVE: We assessed the role of dynamic CT in the evaluation of the efficacy of transarterial chemoembolization with iodized oil for hepatocellular carcinoma. MATERIALS AND METHODS: We examined 41 hepatocellular carcinoma lesions (mean diameter, 5.0 cm) in 40 patients (mean age, 60.6 years) who underwent transarterial injection of iodized oil alone (n = 3) or emulsion of iodized oil and doxorubicin hydrochloride (n = 10) followed by gelatin sponge particles (n = 27) and subsequent hepatectomy. On dynamic CT performed within 3 weeks before oily transarterial chemoembolization and within 4 weeks before surgery, we calculated the rate of necrosis on the basis of the assumption that the portion that retained iodized oil represented necrosis. We also calculated the reduction rate of the tumor. CT findings were compared with pathologic findings of resected specimens. RESULTS: Pathologic specimens and the necrosis rate measured on CT showed a good correlation (r = 0.83) when the portion of tumor that retained iodized oil was considered necrosis. No correlation existed if the portion that retained iodized oil was considered viable. We noted no significant correlation (r = 0.38) between the reduction rate of the tumor and necrosis rate. Also, we noted no correlation (r = 0.52) between the interval between transarterial oily chemoembolization and surgery and the reduction rate of the tumor. CONCLUSION: CT is suitable for the evaluation of the efficacy of oily chemoembolization for hepatocellular carcinoma on the basis of the assumption that the portion of tumor that retains iodized oil is necrotic. The rate of tumor size reduction measured on CT did not correlate with the therapeutic effect of chemoembolization.

Aged↗
PubMed1999

Major degradation pathway of thiuram in tap water processed by oxidation with sodium hypochlorite.

Thiuram (3 microM), a fungicide, was incubated in deionized water by adding 0-100 mg/L free chlorine at 30 degrees C for 30 min, and the solution was analyzed by HPLC and IC. The byproducts were identified by LC/MS, EI-MS, infrared, and (13)C NMR spectra and a reduction technique using 2-mercaptoethanol. On the basis of these results, it was found that the oxidation of thiuram with sodium hypochlorite initially produced an intermediate dimethylthiocarbamoyl dimethylcarbamoyl disulfide, which was finally degraded to bis(dimethylcarbamoyl) disulfide, its trisulfide, and dimethylamine. Subsequently, it was suggested that monitoring of bis(dimethylcarbamoyl) disulfide, its trisulfide, and dimethylamine should be included for the management and control of thiuram in tap water processed by oxidation with sodium hypochlorite.

Chromatography, Liquid↗
PubMed1999

The N-terminal propeptide and the C terminus of the precursor to 20-kilo-dalton potato tuber protein can function as different types of vacuolar sorting signals.

Two types of vacuolar sorting signals (VSSs), an asparagine-proline-isoleucine-arginine-leucine (NPIRL)-related VSS in the N-terminal propeptides (NTPPs) and a C-terminal VSS in the C-terminal propeptides (CTPPs), function differently in plant cells. A precursor to a 20-kDa protein of potato tuber (PT20) contains two NPIRL-related sequences, NPINL in a short NTPP and NPLDV close to the C terminus of the precursor. We made mutant forms of sweet potato sporamin (SPO), nPT20-SPO, in which the N-terminal pre-pro part was exchanged with that of the precursor to PT20, and SPO-PT20c, in which the C-terminal 13 amino acids of the precursor to PT20 was attached to the C terminus of delta pro-SPO which lacked NTPP. Both nPT20-SPO and SPO-PT20c were efficiently transported to the vacuoles in tobacco cells. Unlike nPT20-SPO, the vacuolar transport of SPO-PT20c was inhibited by wortmannin and by the C-terminal addition of Gly or Gly-Gly suggesting its similarity to the vacuolar transport of sporamin mediated by CTPP of barley lectin. Further analysis of the C-terminal sequence of PT20 indicated that the most C-terminal SFKQVQ sequence functions as the C-terminal VSS. These results suggest that the precursor to PT20 contains both NPIRL-like VSS in its NTPP and C-terminal VSS at the C terminus.

Amino Acid Sequence↗
PubMed1998

Arabidopsis LEAFY COTYLEDON1 is sufficient to induce embryo development in vegetative cells.

The Arabidopsis LEAFY COTYLEDON1 (LEC1) gene is required for the specification of cotyledon identity and the completion of embryo maturation. We isolated the LEC1 gene and showed that it functions at an early developmental stage to maintain embryonic cell fate. The LEC1 gene encodes a transcription factor homolog, the CCAAT box-binding factor HAP3 subunit. LEC1 RNA accumulates only during seed development in embryo cell types and in endosperm tissue. Ectopic postembryonic expression of the LEC1 gene in vegetative cells induces the expression of embryo-specific genes and initiates formation of embryo-like structures. Our results suggest that LEC1 is an important regulator of embryo development that activates the transcription of genes required for both embryo morphogenesis and cellular differentiation.

Amino Acid Sequence↗
PubMed1998

Characterization of a calcium-dependent protein kinase of tobacco leaves that is associated with the plasma membrane and is inducible by sucrose.

The plasma membrane fraction from leaves of tobacco contains a 54-kDa protein with autophosphorylation activity, and the level of this protein increases after feeding of leaves with sucrose [Ohto and Nakamura (1995) Plant Physiol. 109: 973]. The 54-kDa autophosphorylation protein could not be released from the plasma membrane by treatment with salt or alkali but could be efficiently solubilized by 1% sodium deoxycholate (NaDOC). Ion-exchange chromatography of the NaDOC-solubilized proteins in the presence of octylglucoside separated the 54-kDa autophosphorylation protein into three peaks. The autophosphorylation activity of the 54-kDa protein in peaks I and II increased after feeding of leaves with sucrose. The 54-kDa protein in the peak II fraction was enriched about 125-fold starting from the microsomal membrane fraction. The 54-kDa protein in this fraction phosphorylated histone IIIS in a calcium-dependent manner and cross-reacted with an antibody against a calcium-dependent protein kinase (CDPK) of Arabidopsis thaliana. These results suggest that the 54-kDa protein in the peak II fraction is a novel isoform of CDPK which is associated with the plasma membrane and is inducible by sucrose.

Arabidopsis↗
PubMed1997

Clinical efficacy of lactulose in cirrhotic patients with and without subclinical hepatic encephalopathy.

Seventy-five cirrhotic patients with hyperammonemia in the past or at the time of the study were randomly divided into two groups (treated with lactulose or nontreated) in 14 hospitals in Japan. Thirty-six cirrhotic patients were diagnosed as having subclinical hepatic encephalopathy (SHE), and 39 were diagnosed as non-SHE. SHE was diagnosed when the results of all three of the quantitative psychometric tests used (number connection test, and symbol digit and block design tests of the Wechsler adult intelligence scale [revised]) were abnormal as compared with age-matched normal values. The mean number of abnormal psychometric test results and the prevalence of SHE were used for a quantitative evaluation of the efficacy of the lactulose treatment. Twenty-two of the SHE patients were treated with lactulose (45 mL/d) for 8 weeks, and the other 14 SHE patients did not receive lactulose. In the SHE patients administered lactulose, the results of the quantitative psychometric evaluation were significantly improved at 4 and 8 weeks after the beginning of the lactulose administration. The SHE had disappeared in 10 (50%) of the 20 treated patients at week 8, but it persisted in 11 (85%) of the untreated 13 patients. We concluded that lactulose treatment in cirrhotic patients with SHE is effective with respect to psychometric tests.

Administration, Oral↗
PubMed1996

Gene expression and active virus replication in the liver after injection of duck hepatitis B virus DNA into the peripheral vein of ducklings.

BACKGROUND/AIMS: Duck hepatitis B virus is a member of the hepadnavirus family, which possesses strong hepatotropism. Duck hepatitis B virus DNA serves as a replicative template for producing biologically active virus particles after transfection into cell lines established from human hepatocellular carcinoma or into duck liver by direct injection of calcium phosphate-precipitated DNA. Our aim was to develop a new method of liver-specific gene expression after intravenous DNA delivery. METHODS/RESULTS: We inoculated duck hepatitis B virus DNA with and without cationic liposomes, Lipofectin or LipofectAMINE, as DNA carries. Two weeks after a single intravenous injection of 10 or 50 micrograms of plasmid DNA containing a head-to-tail dimer of duck hepatitis B virus DNA into 25 one-day old ducklings, duck hepatitis B virus RNA transcripts including the pregenome replicative intermediate were detected by Northern blot in the liver of eight ducks (100%) of the Lipofectin group, five ducks (63%) of the LipofectAMINE group, and three ducks (50%) of the group which received DNA without carrier. Duck hepatitis B virus RNA transcription was almost exclusively liver specific, even though the liposomes had no tissue specificity. Replicative forms of duck hepatitis B virus DNA were detected in the liver and DHBsAg was observed in the cytoplasm of the hepatocytes by immunostaining. The serum of transfected ducklings contained virus particles which were infectious in other ducklings. CONCLUSION: The efficient and liver-specific expression of inoculated DNA was due to the amplification of nucleic acids by active virus replication process under the control of hepatocyte specific regulation.

Animals↗
PubMed1996

Expression of variant CD44-messenger RNA in colorectal adenocarcinomas and adenomatous polyps in humans.

BACKGROUND & AIMS: Recent studies have shown that some variant forms of CD44, a transmembrane glycoprotein expressed on various cell surfaces, might be involved in tumor progression or tumor metastasis. The aim of this study was to analyze the expression of CD44-messenger RNA (mRNA) in colorectal cancer and colorectal adenoma to further elucidate the role of CD44 in colorectal tumorigenesis. METHODS: The expression of CD44-mRNA was examined in 90 specimens from 44 patients with colorectal cancer or colorectal adenomatous polyps and in the peripheral blood leukocytes from 7 healthy volunteers by reverse transcription-polymerase chain reaction and Southern blot hybridization. RESULTS: Strong expression of the epithelial form and variant forms containing exons 11 or 12 of the CD44 gene, which conferred metastatic behavior to rat cells, was detected in primary and metastatic tumor tissues, whereas it was very weak or not detectable in normal colonic mucosae, normal liver tissue, or peripheral blood leukocytes. However, adenomatous colorectal polyps also showed as strong an expression of epithelial and variant forms of CD44 as primary and metastatic tumor tissues. CONCLUSIONS: These results suggest that variant forms of CD44-mRNA might be expressed in an early stage of colorectal carcinogenesis.

Adenocarcinoma↗
PubMed1996

Detection of hepatocellular carcinoma after interferon therapy for chronic hepatitis C: clinical study of 26 cases.

The clinical findings in 26 patients in whom hepatocellular carcinoma (HCC) was detected after the start of interferon (IFN) therapy for chronic hepatitis C were analysed. Histological study before IFN therapy showed that 34.6% of patients were categorized as stage 3 (septal fibrosis with architectural distortion; the 0-4 scale) and 80.8% demonstrated at least some evidence of septal fibrosis or more advanced features. The AFP levels examined before IFN therapy were more than 20 ng/mL in 13 patients (84.6% of those studied). One of 26 patients had a complete response to IFN therapy, while six of 26 patients had only a partial response. HCC was detected within 1 year after the start of IFN therapy in 76.9% of patients. Thus, the possibility of the early occurrence of HCC or its existence at the time of therapy should be seriously considered when IFN therapy is contemplated. Patients with stage 3 or 3-4 histology may already have a small undetectable HCC before IFN therapy. Thus, for this reason, every patient treated with IFN should be examined at short regular intervals for the development of HCC during and after IFN therapy.

Adult↗
PubMed1996

Does gallstone formation after open cardiac surgery result only from latent hemolysis by replaced valves?

OBJECTIVES: To clarify the relationship between open heart surgery and gallstone formation. METHODS: Fifty-one patients without gallstones (Group A) underwent cardiac surgery using a heart-lung machine and were followed for 24 months by ultrasonography. Blood tests of hemolysis markers were examined before, immediately after, and 3, 6, and 12 months after surgery. And 52 healthy candidates without gallstone (Group B) also were followed for 24 months. RESULTS: The cumulative gallstone incidence in Group A was 15.7% at 3 months after surgery, 23.9% at 6 months, and 30.4% at and beyond 12 months and was significantly higher than that of Group B (p < 0.01). The stones showed a high dense pattern, indicative of pigment stones, in eight of the 10 patients assessed by CT. With respect to the type of surgery, latent hemolysis was seen only in patients who underwent mechanical valve replacement. However, there were no significant differences in the gallstone incidence between the patients who underwent mechanical valve replacement and those who underwent another cardiac surgery. The values of hemoglobin, haptoglobin, and lactate dehydrogenase showed abnormal values immediately after surgery, regardless of mechanical valve replacement or another cardiac surgery. CONCLUSIONS: The use of a heart-lung machine, which produces hemolysis, appears to have a close relation to gallstone formation after open cardiac surgery.

Cardiac Surgical Procedures↗
PubMed1995

Doppler velocity histogram analysis of hepatocellular carcinoma.

To study the characteristics of tumor blood flow, flow profiles from hepatocellular carcinomas (39 profiles) and normal hepatic arteries (23 profiles) were evaluated using velocity histograms obtained with Doppler ultrasound. The histograms were classified into three types: (1) high-peak, (2) flat, and (3) low-peak. Characteristically, the low-peak types and the flat types, with flows in opposing directions, were seen only in the tumor vessels. The turbulence in a phantom flow model was of the low-peak type. Spectral analysis revealed that the velocity profile of tumor blood flow was different from that of noncancerous flow and that tumor blood flow was characterized by turbulence.

Blood Flow Velocity↗
PubMed1995

Study of repeated arterial infusion chemotherapy with a subcutaneously implanted reservoir for advanced hepatocellular carcinoma.

We performed repeated arterial infusion chemotherapy (RAIC) in 114 advanced hepatocellular carcinoma (HCC) patients, using a subcutaneous reservoir implanted under ultrasonic guidance. In 60 patients, this was the initial therapy for the primary tumor and the other 54 patients being treated for recurrent tumor. One hundred and seventy-one patients with advanced HCC who had been treated by transcatheter arterial embolization (TAE) or single bolus arterial infusion chemotherapy before RAIC was available served as historical controls. In 97 patients, anticancer agents (4'-epidoxorubicin or acurarubicin) and Lipiodol emulsion were used, and in 17, anticancer agents alone were given. The response rates were 39.2% in the Lipiodol group and 17.6% in the non-Lipiodol group. The dose of Lipiodol and the degree of liver invasion were the most important factors influencing the response rate. The 1-, 2-, and 3-year survival rates were 55.0%, 30.9%, and 21.2%, respectively. The long-termsurvival was compared in relation to Child's classification and the presence or absence of portal vein tumor thrombosis (PVTT). In non-PVTT patients, the results of initial therapy and therapy for recurrence were similar, but recurrent Child's C patients showed a poorer prognosis. In PVTT patients, initial therapy had a better prognosis than treatment for recurrence, but initial Child's C patients had a poor long-termprognosis. During the observation period, no severe complications were encountered, but in Child's C patients, hepatic function sometimes deteriorated. Compared with the results in the 171 controls, RAIC was more useful for advanced HCC as initial therapy, and it was also beneficial for the treatment of recurrence after TAE.

Aged↗
PubMed1995

Response of blood flow to vasopressin in the collateral left gastric vein in patients with portal hypertension.

BACKGROUND/AIMS: A problem in pharmacotherapy for bleeding varices in portal hypertension is non-responders. The aim of this study was to elucidate the features of hemodynamic response to vasopressin in the gastroesophageal collateral vein in patients with esophageal varices. METHODS: Flow velocity in the portal and the collateral left gastric vein was measured with an echo-Doppler flowmeter before and during infusion of vasopressin, 0.2 U/min, in 41 patients with cirrhosis and esophageal varices. RESULTS: The decrease in flow velocity in the left gastric vein with vasopressin (-29 +/- 25%) was significantly smaller than that in the portal vein (-56 +/- 20%). There was no or only minimal change in flow velocity in the left gastric vein in 39% of the patients, especially in those with large-size varices. In 28 patients examined by portal catheterization, changes in flow velocity in the left gastric vein were correlated with portal pressure, and portal pressure in non-responders was significantly higher than that in responders (non-responders: 363 +/- 49, responders: 312 +/- 41 mmH2O, p < 0.05). CONCLUSIONS: It was concluded that hepatofugal blood flow in the gastroesophageal collateral is not readily reduced by vasopressin. However, as the study was performed in a stable condition without variceal bleeding, whether these hemodynamic features will apply during acute variceal bleeding in patients who are known to have a poor hemodynamic response to vasopressin remains to be elucidated.

Aged↗