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M Hirose

Publications and source records attributed to M Hirose.

At least 91 records · Page 5Linked to original sources
PubMed2001

Evaluation of three-dimensional finite element-based deformable registration of pre- and intraoperative prostate imaging.

In this report we evaluate an image registration technique that can improve the information content of intraoperative image data by deformable matching of preoperative images. In this study, pretreatment 1.5 tesla (T) magnetic resonance (MR) images of the prostate are registered with 0.5 T intraoperative images. The method involves rigid and nonrigid registration using biomechanical finite element modeling. Preoperative 1.5 T MR imaging is conducted with the patient supine, using an endorectal coil, while intraoperatively, the patient is in the lithotomy position with a rectal obturator in place. We have previously observed that these changes in patient position and rectal filling produce a shape change in the prostate. The registration of 1.5 T preoperative images depicting the prostate substructure [namely central gland (CG) and peripheral zone (PZ)] to 0.5 T intraoperative MR images using this method can facilitate the segmentation of the substructure of the gland for radiation treatment planning. After creating and validating a dataset of manually segmented glands from images obtained in ten sequential MR-guided brachytherapy cases, we conducted a set of experiments to assess our hypothesis that the proposed registration system can significantly improve the quality of matching of the total gland (TG), CG, and PZ. The results showed that the method statistically-significantly improves the quality of match (compared to rigid registration), raising the Dice similarity coefficient (DSC) from prematched coefficients of 0.81, 0.78, and 0.59 for TG, CG, and PZ, respectively, to 0.94, 0.86, and 0.76. A point-based measure of registration agreement was also improved by the deformable registration. CG and PZ volumes are not changed by the registration, indicating that the method maintains the biomechanical topology of the prostate. Although this strategy was tested for MRI-guided brachytherapy, the preliminary results from these experiments suggest that it may be applied to other settings such as transrectal ultrasound-guided therapy, where the integration of preoperative MRI may have a significant impact upon treatment planning and guidance.

Biophysical Phenomena↗
PubMed2001

Nitric oxide donors retard wound healing in cultured rabbit gastric epithelial cell monolayers.

Effects of nitric oxide (NO) on gastric wound healing were investigated in primary rabbit gastric epithelial cell cultures. We analyzed the speed of cell migration, proliferation, and apoptosis after creating a round wound on the cell cultures. The monolayers were incubated with or without the NO donor sodium nitroprusside, oxatriazolimine 1,2,3,4-oxatriazolium, 5amino-3-(3,4-dichlorophenylchloride), or the peroxynitrite generator 3-morpholinosydnomine-N-ethylcarbamide. The possible role of cGMP as a second messenger of NO was investigated with 8-bromo-cGMP. The role of O2(-*) was evaluated using diethyldithiocarbamate and pyrogallol. The effects of superoxide dismutase and allopurinol were also investigated. NO inhibited the speed of cell migration and proliferation and induced cell apoptosis in a dose- and time-dependent manner. The effects were augmented with O2(-*) generators and ameliorated by O2-(8) scavengers, whereas cGMP had no significant effect on wound healing. NO donors retard gastric wound healing by inhibiting migration and proliferation and inducing cell apoptosis. These effects do not seem to be mediated via cGMP, but O2(-*). or peroxynitrites may be involved.

Animals↗
PubMed2001

Effects of pituitary adenylate cyclase-activating polypeptide on canine atrial electrophysiology.

We hypothesized that pituitary adenylate cyclase-activating polypeptide (PACAP) activates intracardiac postganglionic parasympathetic nerves and has a different effect than cervical vagal stimulation. We measured effective refractory period (ERP) and conduction velocity at four atrial sites [high right atrium (HRA), low right atrium (LRA), high left atrium (HLA), and low left atrium (LLA)] and minimum atrial fibrillation (AF) cycle length at 12 atrial sites during cervical vagal stimulation and after PACAP in 26 autonomically decentralized, open-chest, anesthetized dogs. PACAP shortened ERP to a similar extent at all four sites (HRA, 58 +/- 2.0 ms; LRA, 60 +/- 6.3 ms; HLA, 68 +/- 11.5 ms; and LLA, 60 +/- 8.3 ms). Low- and high-intensity vagal stimulation shortened ERP at the HRA, but not in the other atrial sites (low-intensity stimulation: HRA, 64 +/- 4.0 ms; LRA, 126 +/- 5.1 ms; HLA, 110 +/- 9.5 ms; and LLA, 102 +/- 11.5 ms; high-intensity stimulation: HRA, 58 +/- 4.2 ms; and HLA, 101 +/- 4.0 ms). Conduction velocity was not altered by any intervention. Minimum AF cycle length after PACAP was similar in both atria but was shorter in the right atrium than in the left atrium during vagal stimulation. After atropine administration, no interventions changed ERP. These results suggest that PACAP shortens atrial refractoriness uniformly in both atria through activation of intrinsic cardiac nerves, not all of which are activated by cervical vagal stimulation.

Animals↗
PubMed2001

Immortalized gonadotropin-releasing hormone neurons (GT1-7 cells) exhibit synchronous bursts of action potentials.

Although it has been assumed that synchronized firing of gonadotropin-releasing hormone (GnRH) neurons is necessary for pulsatile GnRH secretion, there is no clear evidence for this. In the present study we simultaneously recorded spontaneous action potentials from multiple cells. Immortalized GnRH neurons (GT1-7 cells) were cultured on a multi-electrode dish (MED) and action potentials recorded by an extracellular recording method. One to two weeks after the beginning of culture, spontaneous action potentials appeared, exhibiting bursts composed of 5-10 action potentials. Burst activity was intermittent and periodic with mean burst intervals of 13.3 s. Furthermore, burst activity was recorded almost simultaneously from several micro-electrodes, suggesting that electrical activities of GT1-7 cells were synchronized with each other. Periodic bursts were completely and reversibly blocked by 1-5 microM tetrodotoxin, indicating that voltage-dependent Na(+) channels are involved in their generation. gamma-Aminobutyric acid (GABA) given at a 10-microM concentration shortened inter-burst intervals, whereas 10 microM bicuculline lengthened them. Finally, the gap junctional blockers n-octyl alcohol (1 mM) and carbenoxolone (100 microM) reversibly blocked periodic burst activity. The present study provides direct evidence that the electrical activity of GT1-7 cells exhibits synchronous and periodic bursts composed of action potentials. In addition, endogenous GABA is involved in GT1-7 cells in determining burst frequency. Although the precise mechanism of synchronized burst activities needs to be clarified, gap junctional communications among GT1-7 cells are at least partially involved.

1-Octanol↗
PubMed2001

Dose-dependent promotion by phenylethyl isothiocyanate, a known chemopreventer, of two-stage rat urinary bladder and liver carcinogenesis.

The effects of phenylethyl isothiocyanate (PEITC) on urinary bladder and liver carcinogenesis were analyzed in a rat model. Diets containing 0.1%, 0.05%, or 0.01% PEITC were administered for 32 wk to male Fischer 344 rats with and without pretreatment with an injection of diethylnitrosamine (200 mg/kg body wt i.p.) and 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine in the drinking water for 4 wk for initiation. In the initiated groups, PEITC administration significantly increased the incidences of papillary or nodular hyperplasia, dysplasia, and transitional cell carcinomas at higher doses of 0.01%, 0.01%, and 0.05%, respectively, compared with the control group, given initiation alone, in a dose-dependent manner. Without initiation, administration of 0.1% and 0.05% PEITC induced simple and papillary or nodular hyperplasia and dysplasia in the urinary bladder. In the liver, induction of glutathione S-transferase placental form-positive foci was dose dependently enhanced by PEITC administration, but the incidences of liver tumors were not different among the groups. From the present experiment, we can conclude that > 0.01% PEITC enhances rat urinary bladder carcinogenesis, while weakly promoting hepatocarcinogenesis. In addition, it is suggested that > 0.05% PEITC has tumorigenic potential.

Animals↗
PubMed2001

Diastereoselective synthesis of (2R,4R)-2-aryl-4-hydroxypyrrolidine: preparation of the side chain of novel carbapenem.

Improved synthesis of the trans-3,5-disubstituted pyrrolidin-3-ylthio side-chain of the novel carbapenem 1 was achieved via stereoselective reduction of the 1-aryl-1-butanone derivative 5 and successive intramolecular cyclization of the resulting chiral alcohol 6. The 1-aryl-1-butanone derivative 5 was obtained by a coupling reaction of protected 4-hydroxy-2-pyrrolidone with aryl-Grignard reagent.

Carbapenems↗
PubMed2001

Thermostabilization of ovalbumin in a developing egg by an alkalinity-regulated, two-step process.

Native ovalbumin has been known to convert into a heat-stable form, S-ovalbumin, either in an avian shell egg or in an isolated ovalbumin solution. Recently, similar conversion of ovalbumin in fertile eggs was also reported. We found that the conversion into S-ovalbumin was slower in fertile eggs than in unfertile eggs under the same incubation conditions on the basis of calorimetric analyses for the samples isolated from those eggs. During the incubation, there were differential pH changes of white in the fertile and unfertile eggs. When the pH of purified ovalbumin was manually adjusted so as to simulate the pH changes of egg white during the incubation, the course of the conversion into S-ovalbumin was very similar to that either in fertile or unfertile eggs. Therefore, we conclude that thermostabilization of ovalbumin in fertile eggs proceeds by a certain mechanism which depends on the alkalinity of egg white.

Animals↗
PubMed2001

Expression of cytokines and inducible nitric oxide synthase in inflamed gingival tissue.

BACKGROUND: Periodontopathic bacteria induce inflammation of periodontal tissues. The cytokines and nitric oxide released in periodontal lesions have been reported to play a protective role in bacterial infection and to relate to the process of inflammation. To clarify the relationship between colonization of periodontopathic bacteria and cytokines, we evaluated profiles of inflammatory cytokines, chemokine, anti-inflammatory cytokines, and inducible nitric oxide synthase (iNOS) and colonization by Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans, which are major pathogens of periodontitis. METHODS: mRNA expression of cytokines and iNOS in inflamed and healthy gingival tissue was determined using reverse transcription-polymerase chain reaction (RT-PCR), and the relationship between their profiles and the detection of specific bacteria was analyzed. RESULTS: The relative expression of interleukin (IL)-6 and iNOS mRNAs in periodontal lesions was significantly higher than those in healthy individuals. IL-6 mRNA expression was also significantly higher at bleeding on probing (BOP)-positive sites than at BOP-negative sites. The expressions of IL-1alpha and IL-8 increased, but IL-10 expression decreased at sites where A. actinomycetemcomitans was detected. We found no correlation between the expression of cytokine and iNOS mRNA and infection by P. gingivalis. CONCLUSIONS: The expression of IL-6 may reflect inflammation in gingival tissue, and iNOS may be involved in the inflammatory process in periodontitis. The presence of A. actinomycetemcomitans or P. gingivalis might relate to the different cytokine profiles of IL-1alpha, IL-8, and IL-10.

Actinobacillus Infections↗
PubMed2001

Lack of modifying effects of eugenol on development of lung proliferative lesions induced by urethane in transgenic mice carrying the human prototype c-Ha-ras gene.

To investigate the modifying effects of eugenol (EUG), a component of cigarette smoke, on lung carcinogenesis, male and female transgenic mice carrying the human prototype c-Ha-ras gene (rasH2 mice) were given a single intraperitoneal injection of 250 mg/kg urethane (UR) or saline, followed by a diet containing 6,000 ppm EUG or basal diet for 26 weeks. Their non-transgenic CB6F1 littermates (non-Tg mice) were also treated in the same manner. In both male and female rasH2 mice, alveolar/bronchiolar hyperplasias, adenomas and carcinomas were observed in all UR-treated groups. However, there were no significant intergroup differences in the incidences and multiplicities of these lesions between the UR alone and UR + EUG groups. In non-Tg mice, alveolar/bronchiolar hyperplasias, adenomas or carcinomas were sporadically observed in UR-treated groups of both sexes, with no significant differences in the incidences and multiplicities between the UR alone and UR + EUG groups. There were no intergroup differences between them in the PCNA-positive ratios of adenomas or carcinomas and the areas of adenomas or carcinomas to the whole lung area examined. The present results suggest that the EUG treatment does not exert modifying effects on lung carcinogenesis induced by UR in both male and female rasH2 mice and non-Tg mice.

Adenoma↗
PubMed2001

Dose-threshold for thyroid tumor-promoting effects of orally administered kojic acid in rats after initiation with N-bis(2-hydroxypropyl) nitrosamine.

In order to evaluate the threshold dose of thyroid tumor-promoting effects of KA, male F344 rats were initiated with N-bis(2-hydroxypropyl) nitrosamine (DHPN; 2000 mg/kg body wt., single s.c. injection) and, starting 1 week later, received pulverized basal diet containing 0%, 0.002%, 0.008%, 0.03%, 0.125%, 0.5% or 2%KA for 20 weeks. Five rats each in the 0%, 0.125%, 0.5% and 2%KA groups were sacrificed at week 12, and 10 rats each in all groups at week 20. As an additional experiment, three groups without DHPN initiation received basal diet, a diet containing 0.5% or 2%KA for 20 weeks. The serum T4 levels were significantly decreased in the DHPN-initiated groups given 0.125%KA or more at week 12. No significant decreases in serum T3 levels were observed in the groups treated with DHPN + KA and a significant increase was evident in the 2%KA-alone group at week 20. Some rats in the DHPN + 2%KA group at weeks 12 and 20 and the 2%KA-alone group at week 20 showed pronounced elevation of serum TSH. Thyroid weights were significantly increased in the DHPN-initiated groups receiving 0.5% and 2%KA at weeks 12 and 20 and in the 2%KA-alone group at week 20. Histopathologically, the incidences of focal thyroid follicular cell hyperplasias in the DHPN-initiated groups treated with 0.125%, 0.5% and 2%KA at week 20 were 5/10, 10/10 and 8/8 rats, respectively. At week 20, adenomas were observed in 7/10 rats in the DHPN + 0.5%KA group and 8/8 rats in the DHPN + 2%KA group, and carcinomas were observed in 6/8 rats in the DHPN + 2%KA group. In the groups without DHPN initiation, only focal follicular cell hyperplasia was observed in 1/9 rats in the 2%KA-alone group. These results suggest that the no-observed-adverse effect for the thyroid tumor-promoting effect of KA is 0.03% (15.5 mg/kg/day) under the present experimental conditions, and that KA possesses weak tumorigenic activity in rats due to continuous serum TSH stimulation by a non-genotoxic mechanism.

Animals↗
PubMed2001

Reporter gene transgenic mice as a tool for analyzing the molecular mechanisms underlying experimental carcinogenesis.

Carcinogenic compounds are classified into 2 categories, genotoxic and non-genotoxic, which are basically judged from in vitro genotoxicity data. However, it is well documented that genotoxicants do not necessarily exert in vivo carcinogenicity in rodents, partly because of a discrepancy between in vitro and in vivo mutagenicities. Recently, transgenic animal models with reporter genes such as lacI, lacZ and gpt have been developed as a tool for assessing in vivo mutagenicity as well as carcinogenicity. In this article, data using lacI transgenic mice and gpt delta mice are presented and their application is discussed. In lacI transgenic mice, dimethylnitrosamine (DMN) treatment significantly increased lacI mutant frequency (MF) in the liver, kidenys and lungs, but not in other non-target organs. Repeated dose ip administration of DMN was more effective than single dose treatment in the induction of lacI MF. The spectrum of mutant plaques induced by DMN was characterized by deletions as well as GC to AT base transitions. The remaining mice receiving DMN proved to have liver adenomas at a high frequency after 78 weeks. Meanwhile, dietary 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MelQx) significantly increased lacI and gpt MFs in the liver and colon. The characteristic spectrum of mutant plaques induced by MeIQx was a GC to TA base transversion in both the lacI and gpt mutations. Our results thus strongly suggest that these reporter gene transgenic animal models could offer a useful tool for analyzing molecular mechanisms underlying experimental carcinogenesis and for assessing the carcinogenic risk of environmental chemicals.

Animals↗
PubMed2001

[Anesthesia for a patient with alcoholic heart disease and transient complete heart block].

A 70-year-old man who had been drinking a bottle of whisky each day was scheduled for laser resection of a tongue tumor. His electrocardiogram showed sinus bradycardia (heart rate was 35-40 bpm), and transient complete heart block was observed. Echocardiography showed hypertrophic cardiomyopathy. After a temporary transvenous pacemaker had been inserted, anesthesia was induced with thiopental and vecuronium bromide, and maintained with sevoflurane and fentanyl. Heart rate was 45.min-1 before the induction of anesthesia, and after the induction increased to 70-80.min-1. Analysis of heart rate variability suggested that the increase in heart rate was due to augmentation of sympathetic nervous activity after intubation and operation stress. After the operation his bradycardia improved gradually, and after 3 months heart rate settled at about 55.min-1. Cadiomyopathy is known to be one of the complications of alcoholism. It was reported that alcoholic heart disease was improved promptly by abstinence from alcohol. During his long hospitalization, abstinence might have improved his severe bradycardia. Thiopental is useful for induction of anesthesia in a patient with severe bradycardia from alcoholic cadiomyopathy.

Aged↗
PubMed2001

[A case of right pneumonectomy and omentopexy for lung cancer after preoperative irradiation].

A 72-year-old man complaining of cough rejected the operation for squamous cell carcinoma obstructing the right intermediate trunk, therefore he was received 82 Gy (40 Gy and 42 Gy) of radiotherapy. However, the tumor did not decrease, in addition, cough and purulent sputum became severe gradually. We performed right pneumonectomy and omentopexy to prevent bronchial fistula, he had no pulmonary complication. Radiotherapy is a risk factor for postoperative bronchial fistula, omentopexy is useful to prevent it.

Aged↗
PubMed2001

[MDCT].

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Carcinoma, Hepatocellular↗
PubMed2001

[Clinical utility and safety of diagnostic thoracoscopy].

The increasing use of thoracoscopy performed under local anesthesia has made contributions to the diagnosis of pleural disease with effusion. During the past 7 years, we have performed 100 such thoracoscopy procedures using a flexible fiberoptic bronchoscope. On the basis of our clinical findings, we are able to discuss the utility and safety of this procedure. The causes of pleural effusion were carcinomatous pleurisy in 72 cases, tuberculosis pleurisy in 15 cases, infection without tuberculosis in 4 cases, malignant pleural mesothelioma in 8 cases and one case of asbestosis. The success rate of thoracoscopic pleural biopsies were 97% for carcinomatous pleurisy, 100% for malignant pleural mesothelioma and 86% for tuberculosis pleurisy. This procedure was performed with no serious effect on blood pressure, oxygen saturation, monitored ECG or BGA data, and with no serious complications. Therefore, we concluded that this method is very useful for the diagnosis of pleural effusions and has few complications.

Adult↗
PubMed2000

Modifying effects of 4-phenylbutyl isothiocyanate on N-nitrosobis(2-oxopropyl)amine-induced tumorigenesis in hamsters.

The modifying effects of dietary 4-phenylbutyl isothiocyanate (PBITC), given during the initiation stage of carcinogenesis, were investigated in hamsters treated with N-nitrosobis(2-oxopropyl)amine (BOP). A total of 120 female 5-week-old hamsters were divided into six groups. Animals in groups 1-3, each consisting of 30 hamsters, were given BOP by two subcutaneous injections, 1 week apart, at a dose of 20 mg/kg body weight, plus 0, 10 or 100 micromol/animal of PBITC in corn oil by gavage 2 h prior to each carcinogen treatment. Ten animals in group 4 served as a vehicle control, and animals in groups 5 and 6, each consisting of ten hamsters, were given 10 and 100 micromol of PBITC alone in corn oil. Sacrifice was 52 weeks after the first BOP injection. The PBITC treatments significantly (P<0.05) inhibited the development of pancreatic ductal dysplasias and adenocarcinomas. Also, lung tumors (adenomas and adenocarcinomas) were significantly (P<0.05) reduced in a dose-dependent manner. In contrast, both hepatocellular and cholangiocellular tumors (adenomas and carcinomas) tended to be or were significantly increased by PBITC. These results, taken together with our previous findings, indicate that the natural isothiocyanate, phenethyl isothiocyanate (PEITC), has a more potent chemopreventive action against BOP-induced tumorigenesis than synthetic isothiocyanates with longer alkyl chains, such as 3-phenylpropyl isothiocyanate (PPITC) and PBITC. Thus, their lipophilicity does not necessarily reflect the chemopreventive potential because the strength of lipophilicity is PEITC<PPITC<PBITC.

Adenocarcinoma↗
PubMed2000

Binding of a large chondroitin sulfate/dermatan sulfate proteoglycan, versican, to L-selectin, P-selectin, and CD44.

Here we show that a large chondroitin sulfate proteoglycan, versican, derived from a renal adenocarcinoma cell line ACHN, binds L-selectin, P-selectin, and CD44. The binding was mediated by the interaction of the chondroitin sulfate (CS) chain of versican with the carbohydrate-binding domain of L- and P-selectin and CD44. The binding of versican to L- and P-selectin was inhibited by CS B, CS E, and heparan sulfate (HS) but not by any other glycosaminoglycans tested. On the other hand, the binding to CD44 was inhibited by hyaluronic acid, chondroitin (CH), CS A, CS B, CS C, CS D, and CS E but not by HS or keratan sulfate. A cross-blocking study indicated that L- and P-selectin recognize close or overlapping sites on versican, whereas CD44 recognizes separate sites. We also show that soluble L- and P-selectin directly bind to immobilized CS B, CS E, and HS and that soluble CD44 directly binds to immobilized hyaluronic acid, CH, and all the CS chains examined. Consistent with these results, structural analysis showed that versican is modified with at least CS B and CS C. Thus, proteoglycans sufficiently modified with the appropriate glycosaminoglycans should be able to bind L-selectin, P-selectin, and/or CD44.

Animals↗