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Biomedical subjects

M Hirota

Publications and source records attributed to M Hirota.

At least 91 records · Page 5Linked to original sources
PubMed1998

[Efficacy of microwave coagulation therapy (MCT) in patients with liver tumors].

We evaluated the efficacy of microwave coagulation therapy (MCT) in 84 patients with hepatocellular carcinomas (HCC) and 40 with metastatic liver tumors (MLT). The response rates calculated with diagnostic imaging were 92% in HCC and 80% in MLT. The regional recurrence rates were relatively higher in patients with MLT (33%) than in HCC (14%). The average surgical margin in operative MCT group was 11 mm. The cumulative survival rates at three and five years were 63% and 38% in HCC and 43% and 33% in MLT, respectively. The complications were similarly encountered in HCC and MLT (12% versus 13%). When these observations are taken together, MCT is a radical and safe locoregional therapy which can keep an adequate surgical margin and assure long survival.

Adolescent↗
PubMed1997

Rapid colorectal adenoma formation initiated by conditional targeting of the Apc gene.

Familial adenomatous polyposis coli (FAP) is a disease characterized by the development of multiple colorectal adenomas, and affected individuals carry germline mutations in the APC gene. With the use of a conditional gene targeting system, a mouse model of FAP was created that circumvents the embryonic lethality of Apc deficiency and directs Apc inactivation specifically to the colorectal epithelium. loxP sites were inserted into the introns around Apc exon 14, and the resultant mutant allele (Apc580S) was introduced into the mouse germline. Mice homozygous for Apc580S were normal; however, upon infection of the colorectal region with an adenovirus encoding the Cre recombinase, the mice developed adenomas within 4 weeks. The adenomas showed deletion of Apc exon 14, indicating that the loss of Apc function was caused by Cre-loxP-mediated recombination.

Adenomatous Polyposis Coli↗
PubMed1997

Effects of muscarinic and adrenergic blockade on growth hormone secretion induced by growth hormone-releasing peptide-2 (GHRP-2) in ovariectomized ewes.

This study was performed to investigate whether the blockade of cholinergic muscarinic and adrenergic pathways was involved in the GH-releasing effect of GH-releasing peptide-2 (GHRP-2) in ovariectomized ewes. Cholinergic muscarinic antagonist, atropine (0.2 mg/kg, i.v., 15 min before GHRP-2 administration) blunted the GH secretion caused by GHRP-2 (12.5 microg/kgBW). alpha-Adrenergic antagonist phentolamine (15 microg/kgBW x min, infusion from -15 to 30 min) did not affect the GH response to GHRP-2, and beta-adrenergic antagonist propranolol (0.25 mg/kgBW, i.v., 15 min before GHRP-2 administration) did not suppress the GHRP-2-induced GH release. These results showed that cholinergic muscarinic antagonist agent, atropine, exerts an inhibitory effect on GHRP-2-induced GH secretion in ovariectomized ewes.

Adrenergic Antagonists↗
PubMed1997

Mutational analysis of the 5' noncoding region of human immunodeficiency virus type 1 genome.

Retrovirus particles are released by budding from the membranes of infected cells. In the course of virus production, particularly during the late stage, viral genomic RNA is incorporated specifically into virion particles. This specific incorporation of the genomic RNA requires a packaging signal sequence. A region that functions as the packaging signal was mapped to a location upstream of the gag open reading frame on the HIV-1 viral genome. In addition of this packaging signal, other cis-acting elements that are scattered throughout the genome are also required for efficient packaging. The region upstream of the splice donor site is probably important for dimer formation. Therefore, we focused on one region located between the 3' end of the primer binding site and the 5' splice donor site of HIV-1. Experiments were conducted to investigate how deletions or point mutations in this region affect both dimerization in vitro and the production of infectious virus particles. A series of RNAs of varying lengths containing the 5' noncoding region were generated, and genomic dimerization of the altered viral RNA was analyzed in vitro. One RNA construct which consisted of 112 nucleotides (nt) from nt 639 to nt 750 formed a heterodimeric complex with the RNA which consisted of 200 nucleotides from nt 551 to nt 750. We then constructed proviruses with mutations in the 639 to 750 nt region and assayed for virus production. Several mutants that lacked the complementarity necessary to form a possible stem-loop structure in this region showed decreased production of infectious virus particles. Moreover, both deletion of this region and randomization of its nucleotide sequence completely impaired infectious virus production. Thus, the way that this region affects infectious virus production may be through its RNA secondary structure.

Animals↗
PubMed1997

[Determination of neutrophil function by measuring superoxide production with whole blood flow cytometry].

The function of neutrophil can be evaluated by measuring oxidative metabolism using chemiluminescence, tetrazolium dye reduction or the others. Those results are not always satisfactory which would be caused by subtle difference in each preparation of the reagents and the lack of reproducibility. Recently, flow cytometric procedures for semi-quantitating superoxide production in neutrophils have been developed to evaluate their function. This procedure, which requires only small amount of whole blood, can easily and rapidly yield reproducible and reliable data. In this study, we optimized analytical conditions and then determined reference interval to evaluate neutrophil function of patients with various disorders. Optimal concentrations and incubation times of DCFH-DA and PMA were 5 mumol/l for 15 minutes and 25 micrograms/ml for 20 minutes, respectively. Production of superoxide in neutrophil was represented by relative fluorescence intensity(RFI) with assay coefficient of variance(CV) of 4.0-11.1%. Neutrophils had to be examined within 2 hours after venipuncture to obtain reliable data. Reference interval was determined as 170.4 +/- 58.7(mean +/- SD) RFI. Neutrophil function of patients with neutropenia, paroxysmal nocturnal hemoglobinuria(PNH), renal failure, systemic lupus erythematosus(SLE), myeloperoxidase deficiency, myelodysplastic syndrome(MDS), and diabetes mellitus were within the reference interval as evaluated by this method. Only neutrophils of chronic granulomatous disease, which is known to give clearly low superoxide production, showed actually decreased value. These results indicate that this procedure would be clinically useful for diagnosis of patient with impaired neutrophil function.

Adult↗
PubMed1996

Site-directed mutagenesis of rat hepatic hydroxysteroid sulfotransferases.

Two cDNA clones of rat hepatic hydroxysteroid sulfotransferase (ST) (ST-40 and ST-20) were isolated and expressed in Escherichia coli cells. Several histidine residues in their coding regions are highly conserved in the ST superfamily, and histidine mutants were constructed by site-directed mutagenesis. The substitution of alanine or lysine for the histidine at position 98 in the ST-40 enzyme resulted in a loss of ST activities toward dehydroepiandrosterone (DHEA), androsterone (AD) and cortisol (CS). The mutation of histidine 98 into alanine abolished the specific binding to 3'-phosphoadenosine 5'-phosphate agarose, suggesting that the residue is located at a critical position in the 3'-phosphoadenosine 5'-phosphosulfate (PAPS) binding site. In the ST-20 enzyme, the replacement of histidine 98 with alanine also resulted in the loss of ST activity toward its preferential substrate, CS. In the ST-40 enzyme, the mutation at histidine 256 into alanine markedly reduced CS-ST activity, but DHEA-ST activity was not changed. Furthermore, selective decrease in CS-ST activity was also observed in the alanine mutant at lysine 254 or at asparagine 255 of the ST-40 enzyme. Kinetic analysis on the ST-40 and its mutant at asparagine 255 indicated that the Km value for CS was significantly increased in the mutant without any change in the Km values for 3'-phosphoadenosine 5'-phosphosulfate and DHEA. Inhibition studies demonstrated that DHEA-ST activity was competitively inhibited by AD, but not by CS in the ST-40 enzyme, whereas triethylamine, a noncompetitive inhibitor of hydroxysteroid ST, inhibited DHEA-ST activity in the ST-40 enzyme but did not inhibit CS-ST activity in either ST-40 or ST-20 enzymes. These data provide evidence that DHEA and CS bind to different sites, which probably function in a different manner in the ST-40 enzyme.

Amino Acid Sequence↗
PubMed1996

Development of a de novo tumorous necrotic lesion in the liver after transcatheter arterial embolization combined with iodized oil infusion: report of a case.

We report herein the case of a 69-year-old woman in whom a hepatic tumorous necrotic lesion was discovered following transcatheter arterial embolization combined with iodized oil infusion (Lp-TAE) for a hepatoma. The lesion, which had not been evident prior to the Lp-TAE, was resected and analyzed pathologically. The portal area distribution in the necrotic lesion was the same as that in the surrounding hepatic tissue, suggesting that the lesion was derived from the nonneoplastic hepatic tissue. Moreover, extensive wall thickening and obstruction were observed in the intrahepatic portal vein and hepatic artery. These findings suggest that the lesion was a focus of hepatic infarction triggered by Lp-TAE.

Aged↗
PubMed1996

Reevaluation of clinical features of ischemic colitis. Analysis of 68 consecutive cases diagnosed by early colonoscopy.

BACKGROUND: Ischemic colitis (IC) is generally considered a disease of elderly patients who have associated diseases. The aim of the present study was to reevaluate the clinical features of IC. METHODS: We retrospectively analyzed the clinical characteristics, background, and endoscopic and histologic changes in 68 consecutive patients (16 men and 52 women) with this disease diagnosed by early colonoscopy. RESULTS: The patients' age ranged from 22 to 98 years (mean, 55 years). Twenty-three patients (34%, including 19 women) were less than 50 years of age. The classical predisposing factors were not discernible in patients younger than 50. Chronic constipation and prior history of abdominal surgery were common in both young and old patients. Early colonoscopy (especially by the 3rd day from onset) showed endoscopic and histologic findings consistent with the characteristics of IC. CONCLUSIONS: IC is not limited only to the elderly, and it should be considered in the differential diagnosis of colitis with melena in younger patients, especially females, who do not have any predisposing factors. Chronic constipation and prior history of abdominal surgery were commonly associated in both young and old patients. Early colonoscopy, especially by the 3rd day from the clinical onset, is essential for the accurate diagnosis of IC.

Abdomen↗
PubMed1996

[A preliminary study of percutaneous ethanol injection therapy for hepatocellular carcinoma: evaluation of the ethanol diffusion area by the ethanol mixed with gadolinium].

To evaluate the ethanol diffusion area after Lipoidalization in 3 patients with advanced HCC treated by Lipoidalization-PEIT combination therapy, 99.9% ethanol mixed with Gadolinium was used for PEIT (Gd-PEIT). T1-weighted MR images wear obtained 1 hr after Gd-PEIT. The area of homogeneous hyperintense change on T1-weighted MR images was taken to be the ethanol diffusion area. In all 3 patients, homogeneous hyperintensity throughout the tumor over the capsule was recognized on T1-weighted MR images after treatment. The results suggests that T1-weighted MR images after Gd-PEIT provide a valuable tool by which to directly evaluate the ethanol diffusion area for advanced HCC treated by Lipoidalization followed by PEIT.

Carcinoma, Hepatocellular↗
PubMed1996

[Immune response induced by surgical trauma].

The non-specific immune response induced by surgical trauma is getting much attention with the concept of systemic inflammatory response syndrome (SIRS). SIRS is recognized as the host response to an inflammatory process independent of its cause, and is characterized by generalized activation of the vascular endothelium and polymorphonuclear leukocyte. It is induced by cytokine production, in which tumor necrosis factor (TNF) and interleukin-1 (IL-1) play a major role. Most of SIRS patients recover from surgical trauma without developing organ dysfunction. However, a new subsequent insult (second attack), such as infection, during SIRS state would lead to amplified tissue response. SIRS should be managed as a warning sign of tissue injury.

Cytokines↗
PubMed1996

Junction of the cystic duct with the left hepatic duct: report of a case discovered during laparoscopic cholecystectomy.

We report a case of an anomalous junction of the cystic duct with the left hepatic duct found during laparoscopic cholecystectomy. Only five other patients with this anatomy have been reported. Two of these five patients had left-sided gallbladders, and the remaining patients (including ours) had their gallbladder in its normal location. Although the prevalence of this anomaly associated with left-sided gallbladders is 5.6 to 14.3%, this anomaly appears to be quite rare in patients with gallbladders in the normal position. In four cases, it was accompanied by left-sided gallbladder or low bifurcation of the common hepatic duct. This rare condition may accompany other biliary anomalies and should be kept in mind when performing cholecystectomy.

Bile Duct Diseases↗
PubMed1995

Inhibition of hepatitis C virus replication by antisense oligonucleotide in culture cells.

Oligonucleotides complementary to the sequences containing the initiator codon, AUG, of the core region of positive-stranded hepatitis C virus (HCV) were tested for their effects on viral translation in a cell-free protein synthesis system and on viral replication in a human T-lymphotropic virus type I infected cell line, MT-2C, which was cloned by the limited dilution method from MT-2 cells and showed more efficient HCV replication than an uncloned population of MT-2 cells. Treatment of HCV-infected MT-2C cells with the antisense oligonucleotide (10 microM) had a dramatic inhibitory effect on viral replication. This result suggests that the antisense oligonucleotide complementary to the sequence close to the initiation codon of the core region might be useful as an antiviral agent against HCV replication.

Antiviral Agents↗
PubMed1995

Characterization of cancer cell dissociation factor in a highly invasive pancreatic cancer cell line.

BACKGROUND: Two pancreatic cancer cell lines, the highly invasive and metastatic cell line PC-1.0 and the weakly invasive and rarely metastatic cell line PC-1, were established from a pancreatic ductal carcinoma induced by N-nitrosobis (2-oxopropyl) amine in a Syrian golden hamster. METHODS: The cancer cell dissociation activity in serum-free conditioned medium of PC-1.0 cells was partially purified using a heparin column, a hydroxylapatite column, anion exchange, and gel filtration high-performance liquid chromatography. Several biologic properties of the partially purified activity were evaluated. RESULTS: Two cell lines exhibited different growth morphologic changes in vitro: the weakly invasive cell line PC-1 formed islandlike colonies, and the highly invasive cell line PC-1.0 grew mainly as single cells. The conditioned medium of PC-1.0 cells induced dissociation of islandlike colonies and morphologic changes of PC-1 cells to elongated cells, with a high frequency of pseudopodia formation similar to the morphologic findings of PC-1.0 cells. The dissociation activity did not bind to the heparin column and had an apparent molecular mass of > 400 kDa, as deduced from gel filtration. Several immunoreactive proteinous bands were observed in immunoblotting analysis using a polyclonal blocking antibody. The partially purified activity enhanced cell motility, chemoinvasion, and cell adhesion to plastic plates and fibronectin. CONCLUSIONS: Highly invasive and metastatic PC-1.0 cells produce a soluble proteinous factor, called "dissociation factor" (DF), which induces cell dissociation of weakly invasive and rarely metastatic PC-1 cells. It seems likely that DF has a role in tumor invasion and metastasis.

Adenocarcinoma↗
PubMed1995

Interferons suppress nerve growth factor synthesis as a result of interference with cell growth in astrocytes cultured from neonatal mouse brain.

Interferon (IFN)-beta and IFN-gamma inhibited the DNA synthesis and nerve growth factor (NGF) synthesis in growing astrocytes cultured from neonatal mouse brain, but they did not affect the NGF synthesis in quiescent astrocytes. IFN-beta and IFN-gamma also inhibited the enhanced DNA synthesis and NGF synthesis in growing astrocytes after the administration of basic fibroblast growth factor. These results indicated that NGF synthesis in astrocytes is regulated by IFNs associated with cell growth. The mechanism of IFN action on NGF synthesis/secretion is unknown, but the results that their effects last long after IFN removal from the cultures present the possibility that IFNs destabilize NGF mRNA.

Animals↗
PubMed1995

Expression of pS2 gene in rat brain.

We have previously shown that the expression of pS2 mRNA, which encodes a secreted 60-amino acid protein of unknown function, is widely distributed throughout the entire body of the mouse including the brain. We report herein that pS2 mRNA is also expressed in the brain and in peripheral tissues of rats. In adult rat brain, pS2 mRNA was predominantly expressed in hippocampus, followed by the cerebral cortex and cerebellum. The developmental expression of pS2 mRNA in hippocampus, which region is known to mature after birth, showed a clear peak in 1- or 3-day-old rats, then gradually decreased by 7 weeks after birth. In midbrain, the maturation of which occurs at an early developmental stage, pS2 mRNA level was retained at a low level from postnatal 1 day to week 7. These results suggest that pS2 protein plays an important role in the development of central nervous system.

Animals↗
PubMed1995

[Perioperative management of patients with Meigs syndrome].

We report our perioperative management of three cases of Meigs syndrome. The major pre-operative problems in Meigs syndrome are physical trouble caused by giant mass in peritoneal space, respiratory distress, and poor nutrition. These problems must be settled before the operation. The important points in the pre-operative management are 1) respiratory care employing the intermittent positive pressure breathing (IPPB) and the pleural effusion drainage, and 2) the correction of intravascular volume and the concentration of albumin and hemoglobin by transfusion of massive lactated Ringer solution and albumin solution and/or whole blood when they are necessary. During the operation, the epidural anesthesia under spontaneous breathing is the best method of anesthesia. According to circumstances, we adopt the intra-tracheal intubation with continuous positive airway pressure breathing (CPAP). We can generally deal with excessive bleeding by transfusion of lactated Ringer solution and plasma expander, during the first half of operation. By the end of the operation, however, the correction of the concentration of albumin and hemoglobin must be made by the fresh frozen plasma and blood transfusion. After the operation, we use epidural analgesia to control the postoperative pain. We have succeeded in the treatment of three cases of Meigs syndrome owing to our perioperative management as described above.

Analgesia, Epidural↗
PubMed1994

Effect of basic fibroblast growth factor on synthesis/secretion of pS2 protein by human breast cancer cells (MCF-7).

pS2 is an estrogen-induced mRNA species that was originally identified in the breast cancer cell line MCF-7. Exposure of the cells to basic fibroblast growth factor (bFGF) at the concentration of 10-100 ng/ml for 48-72 h resulted in a marked increase in the concentration of pS2 protein in the medium. The polymerase chain reaction with reverse transcriptase revealed that bFGF increased the amount of intracellular pS2 mRNA: immunocytochemical studies showed that exposure to the factor increased the amount of intracellular pS2 protein. Simultaneous addition of cycloheximide with bFGF completely abolished induction of pS2 protein, although it did not affect the induction of pS2 mRNA. Actinomycin D did not affect the stimulatory effect of bFGF on synthesis/secretion of pS2 protein. bFGF effectively abolished decay of the pS2 mRNA level caused by actinomycin D. These results suggest that the induction of the synthesis/secretion of pS2 protein by bFGF occurs at the post-transcriptional level, most probably due to the stabilization of pS2 mRNA. Another finding, that bFGF and estradiol have a synergistic effect on induction of pS2 protein, suggests the possibility that these two inducers act by a different but partly overlapping mechanism.

Breast Neoplasms↗