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Biomedical subjects

M Isogai

Publications and source records attributed to M Isogai.

At least 19 recordsLinked to original sources
PubMed2003

The 50-kDa protein of Apple chlorotic leaf spot virus interferes with intracellular and intercellular targeting and tubule-inducing activity of the 39-kDa protein of Grapevine berry inner necrosis virus.

To understand why transgenic Nicotiana occidentalis plants expressing a functional movement protein (MP) of Apple chlorotic leaf spot virus (ACLSV) show specific resistance to Grapevine berry inner necrosis virus (GINV), the MPs of ACLSV (50KP) and GINV (39KP) were fused to green, yellow, or cyan fluorescent proteins (GFP, YFP, or CFP). These fusion proteins were transiently expressed in leaf cells of both transgenic (50KP) and nontransgenic (NT) plants, and the intracellular and intercellular trafficking and tubule-inducing activity of these proteins were compared. The results indicate that in epidermal cells and protoplasts from 50KP plant leaves, the trafficking and tubule-inducing activities of GINV-39KP were specifically blocked while those of ACLSV-50KP and Apple stem grooving virus MP (36KP) were not affected. Additionally, when 39KP-YFP and 50KP-CFP were coexpressed in the leaf epidermis of NT plants, the fluorescence of both proteins was confined to single cells, indicating that 50KP-CFP interferes with the cell-to-cell trafficking of 39KP-YFP and vice versa. Mutational analyses of 50KP showed that the deletion mutants that retained the activities described above still blocked cell-to-cell trafficking of 39KP, but the dysfunctional 50KP mutants could no longer impede cell-to-cell movement of 39KP. Transgenic plants expressing the functional 50KP deletion mutants showed specific resistance against GINV. In contrast, transgenic plants expressing the dysfunctional 50KP mutants did not show any resistance to the virus. From these results, we conclude that the specific resistance of 50KP plants to GINV is due to the ability of the 50KP to block intracellular and intercellular trafficking of GINV 39KP.

Gene Expression Regulation, Plant↗
PubMed2000

Hepatic vein reconstruction by external iliac vein graft using vascular clips.

The utility of hepatic vein reconstruction following resection of segments VII and VIII plus the right hepatic vein (RHV) is still controversial. The purpose of this study was to investigate the surgical benefits of hepatic vein reconstruction using stapled vascular clips and the draining area of hepatic vein using angiographic computed tomography (CT) to determine strict indications for hepatic vein reconstruction. Five patients underwent RHV reconstruction by external iliac vein graft using stapled vascular clips (VCS clips) following resection of segments VII and VIII, regardless of whether an inferior right hepatic vein (IRHV) was present. In eight other patients CT during arterial portography (CTAP) under temporary RHV occlusion using a balloon catheter was performed to determine the drainage area of the RHV. Operating times were 240 to 400 minutes (mean 336 +/- 59 minutes), and the mean hepatic vein reconstruction time was 26 +/- 5 minutes. There were no complications related to the surgery. Follow-up examinations showed patency of the graft in all cases; three patients are still alive with long-term graft patency of 10 to 24 months. CTAP under RHV occlusion demonstrated that segment VI and part of segment V were almost hypoattenuated in cases of absent or small IRHV, although those segments were hyperattenuated in thick IRHV and RHV-IRHV communicating patients. In conclusion, this anastomotic technique using vascular clips resulted in sound patency of the graft, which was accomplished by a simple technique. Preoperative CT AP with the RHV occlusion method can be useful for determining whether hepatic vein reconstruction is necessary.

Aged↗
PubMed2000

Hepatectomy for cholangiocarcinoma complicated with right umbilical portion: anomalous configuration of the intrahepatic biliary tree.

The right umbilical portion (right-sided round ligament) has been discussed as an intrahepatic portal venous anomaly associated with "left-sided gallbladder" in several reports. We treated two patients with right umbilical portion (RUP) associated with cholangiocarcinoma. Left hepatectomies were performed, preserving the residual hepatic blood flow and biliary continuity. From our experience in these patients we propose the presence of anomalous configuration of the intrahepatic biliary tree in RUP, because both patients showed medial segmental bile ducts ramified from the right and left hepatic ducts. In general, although the medial segmental bile duct ramified from the left, we surmised that this abnormal bilateral drainage pattern may not be a rare phenomenon in RUP. Special attention may be required to focus on the anatomy of the portal tributaries and biliary ramifications in RUP.

Bile Duct Neoplasms↗
PubMed2000

Complete nucleotide sequence of the rice tungro spherical virus genome of the highly virulent strain Vt6.

The complete nucleotide sequence of rice tungro spherical virus (RTSV) strain Vt6, originally from Mindanao, the Philippines, with higher virulence to resistant rice cultivars, was determined and compared with the published sequence for the Philippine-type strain A (RTSV-A-Shen). It was reported that RTSV-A was not able to infect a rice resistant cultivar TKM 6 (10). RTSV-Vt6 and RTSV-A-Shen share 90% and 95% homology at nucleotide and amino-acid levels, respectively. The N-terminal leader sequence of RTSV-Vt6 contained a 39-amino acids-region (positions 65 to 103) which was totally different from that of RTSV-A-Shen; the difference resulted from frame shifting by nucleotide insertions and deletions. To confirm the amino-acid sequence differences of the leader polypeptide, the same region was cloned and sequenced using a newly obtained variant of RTSV-type 6, which had been collected in the field of IRRI, and seven field isolates from Mindanao, the Philippines. Since all the sequences of the target region are identical to that of the Vt6 leader polypeptide, the sequence difference in the leader region seems not to correlate with the virulence of Vt6.

Amino Acid Sequence↗
PubMed2000

[A case of ruptured distal aortic arch aneurysm with bronchiolitis obliterans organizing pneumonia].

We report a case of histologically proved bronchiolitis obliterans organizing pneumonia (BOOP) associated with ruptured distal aortic arch aneurysm (DAAA) into the lung. A 63-years-old male with preoperative episode of hemosputum and hemoptysis was diagnosed DAAA. Preoperative computed tomographic scanning demonstrated that the aneurysm was surrounded with the structure of 2 layers of the enhanced high density external layer and the not enhanced low density internal layer. Combined resection of the left upper lobe and the aneurysm was performed safely because of marked adhesion between the lung and the aneurysm. Postoperative histological examination revealed that the perianeurysmal structure was due to BOOP.

Aneurysm, Ruptured↗
PubMed1999

Thirty-six cases of obturator hernia: does computed tomography contribute to postoperative outcome?

Obturator hernia is relatively rare and occurs mostly in elderly, thin, multiparous women. Recent reports have highlighted the importance of pelvic computed tomography (CT) for the preoperative diagnosis. Thirty-six patients with an obturator hernia operated in our hospital were divided retrospectively into two groups (group A: 18 operations from 1973 to 1986, before we used CT; group B: 18 CT cases from 1987 to 1995). Preoperative diagnoses, operative procedures, and postoperative course were reviewed. No statistically significant differences were found between groups A and B in terms of patient characteristics. Rates of accurate preoperative diagnoses were significantly higher in group B: 39% (7/18) in group A and 78% (14/18) in group B (p = 0.018). The intraoperative findings, occurrence of postoperative complications, and overall mortality rates were similar between the two groups. There were four postoperative deaths (mortality rate 11%). Three of four patients who died had panperitonitis because of small bowel perforation. The correct preoperative diagnosis of obturator hernia was facilitated by CT of the pelvis, but it has no impact on patient outcome. Early diagnosis and surgical intervention are essential for this rare entity.

Aged↗
PubMed1999

[Effects of propiverine hydrochloride (propiverine) on the muscarinic receptor binding affinity in guinea pig tissues and on salivation in conscious dogs].

Propiverine is a drug for the treatment of incontinence and pollakiuria. Such micturitional disorders are principally caused by a hyperactive bladder. The effects of propiverine, its active metabolite, 1-methyl-4-piperidyl benzilate N-oxide (DPr-P-4 (N-->O)), oxybutynin and terodiline on muscarinic receptors in guinea pig urinary bladder, salivary glands, cerebral cortex, ileal longitudinal muscle and heart were compared. Both propiverine and DPr-P-4 (N-->O) competitively inhibited specific binding of 3H-quinuclidinyl benzilate (3H-QNB) to membrane fractions of these tissues. Oxybutynin, terodiline, pirenzepine and atropine also competitively inhibited the binding of 3H-QNB. The order of these drugs in terms of their affinity for muscarinic receptors was as follows: atropine > oxybutynin > pirenzepine, DPr-P-4 (N-->O), terodiline > propiverine. Propiverine and DPr-P-4 (N-->O) had no selectivity for muscarinic receptors in these tissues, the same as atropine. In contrast, pirenzepine, a M1-selective drug, had 10.1 times greater affinity for muscarinic receptors in the cerebral cortex than in urinary bladder, and the affinity of oxybutynin for muscarinic receptors in salivary glands and in cerebral cortex was 10.9 times and 13.9 times higher, respectively, than in urinary bladder. The affinity of terodiline for muscarinic receptors in the cerebral cortex was 4.4 times higher than in urinary bladder. In this study, the effect of propiverine and oxybutynin on pilocarpine (1 mg/kg, s.c.)-induced salivation in conscious dogs was also compared. Propiverine (5 mg/kg, i.v.) had no effect on pilocarpine-induced salivation, whereas oxybutynin (0.1 mg-0.5 mg/kg, i.v.) inhibited it significantly and dose-dependently. The ID50 values (95% confidence limits) for propiverine and oxybutynin during the 20 min after intravenous administration were 6.88 mg/kg (4.71-15.67) and 0.154 mg/kg (0.115-0.205), respectively. These findings suggest that although propiverine, its active metabolite DPr-P-4 (N-->O), oxybutynin and terodiline competitively inhibit the binding of 3H-QNB to muscarinic receptors, the affinity of these drugs for the muscarinic receptors of these tissues is very different and that propiverine has less effect on salivation than oxybutynin.

Animals↗
PubMed1998

Leiomyosarcoma of the inferior vena cava. Resection and reconstruction of the renal vein using the gonadal vein.

We succeeded in surgically resecting a leiomyosarcoma of the inferior vena cava (IVC), which originated at the confluent portion of the right renal vein (RRV), together with the IVC and RRV, and also were able to preserve the right kidney by reconstructing the RRV with end-to-end anastomosis using the right gonadal vein. A good blood flow of the reconstructed RRV was thereafter confirmed by color Doppler ultrasonography, and the renal function was also satisfactory. This new procedure, a reconstruction of the RRV using the gonadal vein, has not been previously reported, but is considered to be an easy and effective method which enables the surgeon to preserve the normal right kidney.

Aged↗
PubMed1998

Intraportal stent placement combined with right portal vein embolization against advanced gallbladder carcinoma.

We describe herein the first successful implementation of intraportal stent placement combined with right portal vein embolization as preoperative management against far advanced gallbladder carcinoma. The patient was a 66-year-old woman with obstructive jaundice, in whom computed tomography confirmed that gallbladder carcinoma had invaded the liver and that massive lymph node metastases involved the hepatoduodenal ligament. Portography also revealed severe stenosis of the main portal trunk to less than 2 mm in diameter. To prevent the contribution of intraportal thrombosis and ensure postoperative liver functional reserve, an intraportal metallic stent implantation was conducted simultaneously with right portal vein embolization via a single route using the percutaneous transhepatic approach. There were no complications following this technique, and the patient subsequently underwent hepato-ligament-pancreatoduodenectomy. The resected specimen disclosed a well-expanded stent containing no thrombus. This method could therefore be an amenable strategy for the preoperative treatment of far advanced biliary malignancies in selected patients.

Aged↗
PubMed1998

Taxonomic characteristics of fijiviruses based on nucleotide sequences of the oat sterile dwarf virus genome.

Sequence determination of full-length cDNA clones of genomic segments 7-10 (S7-S10) of oat sterile dwarf fijivirus (OSDV) revealed that the 5' and 3' ends of the plus strands of these segments had the same conserved terminal sequences, 5' AACGAAAAA and UUUUUUUAGUC 3'. These sequences are similar, but not identical, to the conserved terminal nucleotide sequences of the genomic segments of rice black streaked dwarf fijivirus (RBSDV) and maize rough dwarf fijivirus (MRDV). The coding strands of S7 and S10 each contained two large nonoverlapping open reading frames (ORFs), as do RBSDV S7 and S9, MRDV S6 and S8 and Nilaparvata lugens reovirus (NLRV; a putative member of Fijivirus) S9. These results strongly suggest that the dicistronic nature of certain genomic segments is characteristic of fijiviruses. Computer analyses revealed sequence homology between RBSDV S7 ORF2, MRDV S6 ORF2 and OSDV S7 ORF2, suggesting that this protein is conserved among plant fijiviruses. No counterparts were found in the genome of NLRV, which is a nonphytopathogenic insect reovirus. Furthermore, phylogenetic trees derived from multiple sequence alignments of each of the homologous proteins from OSDV, RBSDV, MRDV and NLRV suggest that NLRV did not evolve from either Fijivirus group 2 (RBSDV and MRDV) or group 3 (OSDV).

Amino Acid Sequence↗
PubMed1998

Detection and assignment of proteins encoded by rice black streaked dwarf fijivirus S7, S8, S9 and S10.

The proteins encoded by rice black streaked dwarf fijivirus (RBSDV) genomic segments 7-10 (S7-S10) were characterized. Open reading frames (ORFs) from these segments were expressed as fusion proteins in Escherichia coli. Antibodies raised against the expressed products were used as probes to determine whether the viral ORFs encode structural proteins. In Western blots, antibodies to the expressed S8 and S10 products reacted with a core capsid (65 kDa) and a major outer capsid (56 kDa) protein, respectively, while none of the antibodies to S7 and S9 products reacted with structural proteins. Antisera to RBSDV S7 ORF1 and S9 ORF1 each detected a single protein of the predicted size in total protein extracts from infected rice plants and viruliferous Laodelphax striatellus. Immunoelectron microscopy revealed that antibodies to RBSDV S7 ORF1 and RBSDV S9 ORF1 reacted with tubular structures and viroplasm, respectively, in sections of both infected maize plants and viruliferous L. striatellus. Antisera to ORF2 of S7 and S9 failed to detect any proteins in the infected tissue using either Western blotting or immuno-electron microscopic techniques.

Amino Acid Sequence↗
PubMed1998

LDH to AST ratio in biliary pancreatitis--a possible indicator of pancreatic necrosis: preliminary results.

OBJECTIVE: Lactate dehydrogenase (LDH) has been reported to be a sensitive indicator of pancreatic necrosis (PN). In patients with biliary pancreatitis (BP), however, liver enzymes are generally elevated early in the course of the disease because of acute inflammatory liver cell injury caused by ampullary stones impacted during their transpapillary passage. Accordingly, the identification of PN using the initial high LDH activity as an indicator of PN in BP may not be accurate. In patients with ongoing PN, LDH would be expected to increase thereafter. We hypothesized that an elevation of the ratio of LDH to aspartate aminotransferase (AST) (LDH/AST) would better reflect PN in BP. METHODS: The plasma concentrations of the LDH/AST ratio over a 3-wk postadmission period were evaluated and compared with serial computed tomograpy (CT) scans of the abdomen in two groups of patients with BP, consisting of 5 PN patients and 17 non-PN patients. A group of 50 healthy adults served as controls for the LDH/AST ratio measurement. RESULTS: On postadmission days 1 and 2, the LDH/AST ratios in both groups of patients were low, with no significant difference. In the PN patients, the LDH/AST ratio increased thereafter, reached peak values, and decreased. In the non-PN patients, the LDH/AST ratio increased gradually, but remained within the control range. In the PN patients, the LDH/AST ratios on postadmission days 3, 5, and 7 were significantly higher than those of the non-PN patients. The CT scans of the abdomen of the PN patients showed an initial edematous pancreas with the development of late PN. The peak values of the LDH/AST ratio correlated well with the extent of PN. CONCLUSION: An elevated LDH/AST ratio identifies patients who develop PN. The LDH/AST ratio could be used as an indicator of PN in BP patients.

Adult↗
PubMed1998

Potentiation by neurotensin of carbachol-induced tension development in beta-escin-skinned smooth muscle of guinea-pig ileum.

Effect of neurotensin (NT) on carbachol(CCh)-induced tension development due to Ca2+ release from intracellular stores was investigated in beta-escin-skinned smooth muscle of guinea-pig ileum. NT (10 nM) increased the tension development in response to CCh. NT also increased the tension response to caffeine, another store-Ca2+ releaser. NT did not exert such an effect in pertusis toxin (PTX)-treated preparations. Treatment with isoprenaline to elevate endogenous cyclic AMP levels or with dibutyryl cyclic AMP did not affect the effect of NT. A nonpeptide NT antagonist, SR 48692, failed to block the effect of NT. NT shifted the pCa-tension relationship in the lower direction of Ca2+ concentration. NT was incapable of releasing Ca2+ from intracellular stores. The results suggest that NT may cause an increase in Ca2+ sensitivity of contractile elements to potentiate the CCh-induced tension development due to release of stored Ca2+ and that the effect is mediated by SR 48692-insensitive NT receptors linked to a PTX-sensitive G protein which works with no relation to a change in cytosolic cyclic AMP levels.

Animals↗
PubMed1998

The protective effect of Clostridium novyi type B alpha-toxoid against challenge with spores in guinea pigs.

Clostridium novyi (C. novyi) Type B alpha-toxin was purified from culture supernatant by column chromatography, and was inactivated by formalin. A purified alpha-toxoid vaccine was prepared by mixing it with an aluminum phosphate gel adjuvant. Guinea pigs immunized twice with 4 micrograms or more of alpha-toxin survived against challenge with C. novyi Type B spores. Anti-alpha-toxin (antitoxin) titer was measured by toxin neutralization test using Vero cells. All of the guinea pigs having antitoxin titers of 10 units (U) or more at challenge were survived. In another experiment, guinea pigs were immunized with crude alpha-toxoid vaccines prepared by inactivated culture supernatant or by adding broken bacterial cells to the former. In this experiment, 10 U of antitoxin titer was the border of survival or death after challenge. Guinea pigs with antitoxin titers of less than 5 U, 5 U and 10 U died at 2, 3 to 4 and 4 days, respectively, after challenge. These results suggest that C. novyi alpha-toxin was the main protective antigen against challenge exposure to spores in guinea pigs.

Animals↗
PubMed1998

[Targeted chemotherapy of hepatocellular carcinoma with SMANCS/Lipiodol--how to use SMANCS/Lipiodol].

The first drug only for arterial injection, SMANCS/Lipiodol, which offers targeted chemotherapy for hepatocellular carcinoma (HCC), now commercially available. Based on our experience using SMANCS/Lipiodol for 424 patients with HCC, the golden standard of how to use SMANCS/Lipiodol for complete necrosis of tumor was described. The initial dose of SMANCS/Lipiodol was varied 2 to 6 mg per body, mainly depending on the size of the tumor. All feeding arteries of HCC have to be verified on angiogram, and the drug must be injected via an adequate artery. Sometimes, a tumor changes its feeding arteries. Additional administrations with an interval of one month were done till the entire tumor was filled with SMANCS/Lipiodol (grade 4). One or two months after achievement of grade 4, we must examine how much drug was removed from tumor on CT. If the entire tumor is not filled with the drug, further injections are recommended to maintain grade 4. Almost all tumors shrank in 3 to 4 months while maintaining grade 4. Frequent administration of low doses (1-3 mg per body) is recommended. Discontinvation of administration was done on the following findings; tumor size reduction of over 90% or complete disappearance of tumor stain. With arterial injection therapy of SMANCS/Lipiodol, survival of patients with unresectable HCC was prolonged, especially in 272 patients who were good candidates for therapy. (Those with Child C liver cirrhosis, with a tumor occupying all four segments of the liver, and/or with extrahepatic spread at initial arterial injection of the drug were excluded.) The 1, 2, 5, and 10 year survival rates were 83%, 58%, 34%, and 25%, respectively.

Antineoplastic Agents↗
PubMed1997

Expression of a dominant-negative retinoic acid receptor construct reduces retinoic acid metabolism and retinoic acid-induced inhibition of NIH-3T3 cell growth.

We have previously reported an unexpected relationship between retinoic acid-induced inhibition of cell growth and the ability of various cell lines to metabolize the retinoid. Here, we report that stable expression of the truncated retinoic acid receptor RAR alpha403, transduced in NIH-3T3 cells by a retroviral vector, rendered the cells resistant to retinoic acid for growth inhibition and reduced their ability to metabolize the retinoid at the same time as it blunted the induction of the target gene transglutaminase II. The data suggest that retinoic acid receptors mediate the growth-inhibitory action of retinoic acid as well as its metabolism and the induction of transglutaminase II.

3T3 Cells↗
PubMed1997

Marmoset liver cytochrome P450s: study for expression and molecular cloning of their cDNAs.

Northern blot and immunoblot analyses indicated that considerable levels of CYP2B, CYP2C, CYP2D, CYP2E, and CYP3A were expressed in the liver of untreated marmosets. CYP1A was also expressed but to lesser extents. CYP3A mRNA was also detectable in the small intestine of untreated marmoset; the amount was increased by treatment with polychlorinated biphenyl. From a liver cDNA library, two cDNA clones coding for CYP2D19 and CYP3A21 (clones CM2D-1 and CM3A-10, respectively) were isolated. CM2D-1 and CM3A-10 contained an entire coding region for polypeptide 497 and 503 amino acid residues, respectively. The deduced amino acid sequences of CYP2D19 and CYP3A21 showed 90% identities to human CYP2D6 and CYP3A4, respectively. The value of CYP3A21 was 3% lower than that of cynomolgus monkey CYP3A8. On the other hand, these values were 11 to 23% higher than those of the other experimental animals, including dogs, rabbits, guinea pigs, rats, mice, and hamsters. These results indicate that the marmoset stands at a midpoint between human and nonprimate experimental animals.

Amino Acid Sequence↗