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Biomedical subjects

H Katoh

Publications and source records attributed to H Katoh.

At least 127 records · Page 7Linked to original sources
PubMed2000

The dominant negative H-ras mutant, N116Y, suppresses growth of metastatic human pancreatic cancer cells in the liver of nude mice.

In pancreatic cancer, the mutation of c-K-ras is a critical event of tumor growth and metastasis. We have previously demonstrated a dominant negative effect of N116Y on the growth of pancreatic cancer cells. To evaluate the potential of N116Y for suppressing the metastatic growth of pancreatic tumor cells, we made a replication-deficient recombinant N116Y adenovirus driven by the carcinoembryonic antigen (CEA) promoter (Ad CEA-N116Y). We demonstrated that the expression of N116Y, growth inhibition, and apoptotic death induction were all specific to pancreatic cancer cell lines (PCI-35 and PCI-43) that were promoter positive, whereas no growth retardation was observed in human embryonic pancreas-derived cell line 1C3D3 after Ad CEA-N116Y infection. We examined the effect of Ad CEA-N116Y on the metastatic growth of PCI-43 colonies in liver, which was generated by tumor injection into the spleen of nude mice. The results showed that Ad CEA-N116Y effectively reduced the number of metastatic colonies without any complication by injecting intrasplenically 5 days after tumor cell inoculation. Thus, N116Y can selectively suppress the metastatic growth of pancreatic tumor cell by using the CEA promoter-driven adenovirus vector indicating that N116Y gene therapy may be potentially useful for the treatment of pancreatic cancer patients with liver micrometastasis.

Adenoviridae↗
PubMed2000

Galpha(12) and galpha(13) inhibit Ca(2+)-dependent exocytosis through Rho/Rho-associated kinase-dependent pathway.

The release of neurotransmitters is known to be regulated by activation of heterotrimeric G protein-coupled receptors, although precise mechanisms have not yet been elucidated. To assess the role of the G(12) family of heterotrimeric G proteins in the regulation of neurotransmitter release, we established PC12 cell lines that expressed constitutively active Galpha(12) or Galpha(13) using an isopropyl-beta-D-thiogalactoside-inducible expression system. In the cells, expression of constitutively active Galpha(12) or Galpha(13) inhibited the high K(+)-evoked [(3)H]dopamine release without any effect on the high K(+)-induced increase in intracellular Ca(2+) concentration. A Ca(2+) ionophore ionomycin-induced [(3)H]dopamine release was also inhibited by the expression of active Galpha(12) or Galpha(13). These inhibitory effects of Galpha(12) and Galpha(13) on [(3)H]dopamine release were mimicked by the expression of constitutively active RhoA. In addition, Y-27632, and inhibitor of Rho-associated kinase, a downstream Rho effector, completely abolished the inhibition of [(3)H]dopamine release by Galpha(12), Galpha(13), and RhoA. These results indicate that Ca(2+)-dependent exocytosis is regulated by Galpha(12) and Galpha(13) through a Rho/Rho-associated kinase-dependent pathway.

Animals↗
PubMed2000

Effect of uric acid on liver injury during hemorrhagic shock.

BACKGROUND: It remains unproven whether nitric oxide (NO) exerts a toxic effect on hepatocytes directly or through the formation of a more toxic compound during hemorrhagic shock (HS). NO reacts at a very high rate constant with superoxide to give peroxynitrite, a potentially toxic molecule. In this study, we investigated whether or not peroxynitrite contributed to tissue injury in the liver during HS. METHODS: Male Sprague-Dawley rats were subjected to decompensated HS followed by resuscitation. In addition to the time course of tissue injury and inducible NO synthase (iNOS) messenger RNA (mRNA) expression in the liver during HS, we investigated the effect of N6-(iminoethyl)-L-lysine(LNIL) (a specific inhibitor of iNOS) and also that of uric acid (a natural scavenger of peroxynitrite) on tissue injury and nitrotyrosine formation (a footprint of peroxynitrite) in the liver. RESULTS: The liver injury, evaluated by plasma aminotransferase levels and histology, became evident at the end of the shock period and had significantly increased 1 hour after the start of resuscitation (Shock-1 h). There was no iNOS mRNA expression in the liver at baseline, and it had clearly increased by Shock-1 h. Treatment with LNIL or uric acid significantly attenuated the tissue injury with a prominent reduction in nitrotyrosine formation in the liver. CONCLUSIONS: These lines of evidence suggest that one of the mechanisms by which NO production causes liver injury during HS may be its reaction with superoxide to form peroxynitrite.

Animals↗
PubMed2000

Interaction between L-type Ca2+ channels and sarcoplasmic reticulum in the regulation of vascular tone in isolated rat small arteries.

A dysfunction of the sarcoplasmic reticulum (SR) causes an increase in the myogenic tone of rat skeletal muscle small arteries (A(SK)), but not that of mesenteric small arteries (A(MS)). We hypothesized that the difference depends on the activity of voltage-dependent Ca2+ channels in these vessels. To test this, we measured the membrane potential of these vessels and examined ryanodine-induced constrictions by manipulating the activity of voltage-dependent Ca2+ channels. The isolated vessels were cannulated to control the transmural pressure. To assess the vascular tone, the inner diameter was measured with a video-digitizing system. The membrane potential of A(SK) was more depolarized between 20 to 100 mm Hg of transmural pressure. A(MS) was not constricted by the Ca2+ channel agonist Bay K 8644 (1 nM(-1) microM) alone, but substantially constricted in the presence of ryanodine (1 microM). Ryanodine also augmented the KCl (20 mM)-induced constriction. In A(SK), the Ca2+ channel blocker nisoldipine fully dilated the ryanodine-induced constriction: however, the ryanodine-induced constriction was less susceptible to nisoldipine than was the myogenic and phenylephrine-induced constriction caused mainly by increased Ca2+ influx. In conclusion, the contribution of the SR function to Ca2+ metabolism depends on the activity of dihydropyridine-sensitive Ca2+ channels. The dysfunction of SR by ryanodine may impair the Ca2+ extrusion rather than increase Ca2+ influx in rat small arteries.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed2000

A gene of Synechocystis sp. Strain PCC 6803 encoding a novel iron transporter.

A mutant of Synechocystis sp. strain PCC 6803 disrupted for sll1878 exhibited greatly reduced Fe(3+) transport activity. The K(m) value of sll1878-dependent Fe(3+) transport in cells grown in iron-replete medium was 0.5 microM. Both the maximal rate and K(m) value were increased in iron-starved cells.

Biological Transport, Active↗
PubMed2000

Small GTPase RhoG is a key regulator for neurite outgrowth in PC12 cells.

The Rho family of small GTPases has been implicated in cytoskeletal reorganization and subsequent morphological changes in various cell types. Among them, Rac and Cdc42 have been shown to be involved in neurite outgrowth in neuronal cells. In this study, we examined the role of RhoG, another member of Rho family GTPases, in nerve growth factor (NGF)-induced neurite outgrowth in PC12 cells. Expression of wild-type RhoG in PC12 cells induced neurite outgrowth in the absence of NGF, and the morphology of wild-type RhoG-expressing cells was similar to that of NGF-differentiated cells. Constitutively active RhoG-transfected cells extended short neurites but developed large lamellipodial or filopodial structures at the tips of neurites. RhoG-induced neurite outgrowth was inhibited by coexpression with dominant-negative Rac1 or Cdc42. In addition, expression of constitutively active RhoG elevated endogenous Rac1 and Cdc42 activities. We also found that the NGF-induced neurite outgrowth was enhanced by expression of wild-type RhoG whereas expression of dominant-negative RhoG suppressed the neurite outgrowth. Furthermore, constitutively active Ras-induced neurite outgrowth was also suppressed by dominant-negative RhoG. Taken together, these results suggest that RhoG is a key regulator in NGF-induced neurite outgrowth, acting downstream of Ras and upstream of Rac1 and Cdc42 in PC12 cells.

Animals↗
PubMed2000

Establishment and characterization of the MSKR inbred strain originated from Japanese wild mice (Mus musculus molossinus).

A new inbred strain, MSKR, originated from Japanese wild mice was established in April, 1998. The MSKR mice were 60% of the C57BL/6N inbred mice in the 60-day body weight. Tail length/head-body length and hind-foot length/head-body length of the MSKR mice were significantly smaller than those of the C57BL/6N mice (0.896 vs 1.061, 0.189 vs 0.204), but ear length/head-body length of the MSKR mice was significantly larger than that of the C57BL/6N mice (0.143 vs 0.137). The age of the first parturition and size of the first litter were 63.20 +/- 2.71 days and 6.20 +/- 0.37, respectively, at the 20th and 22nd inbreeding generations. Genetic characterization of the MSKR strain was performed using 34 microsatellite markers, 29 biochemical markers, 9 immunogenetic markers, 3 coat color markers, and mitochondrial DNA RFLP-haplotypes. The result indicated that this newly established inbred strain has some different gene constitution from already known molossinus and common laboratory strains.

Animals↗
PubMed2000

Salmonella contamination in commercial layer feed in Japan.

A total of 4,418 samples of commercial layer feeds obtained in 1998 were investigated for the presence of salmonellae. A total of 146 strains of salmonellae which consisted of 32 serovars, including 20 strains of Salmonella Enteritidis, were isolated from 143 feed samples.

Animals↗
PubMed2000

Usefulness and safety of theophylline injection form (Theodrip) for the treatment of acute asthma.

The effects of the speed of intravenous infusion on the pharmacokinetics of theophylline were studied in 9 healthy volunteers (Ex I). Subjects were intravenously administered either six 4.8 mg/kg theophylline (Theodrip, Nikken Chemicals Co., Ltd., Japan) or three matching placebo injections (4.8 ml/kg physiological saline) for 30 min (Step I) or for 15 min (Step II). In Steps I and II, Cmax was 10.8 +/- 1.1 and 10.8 +/- 0.8 micrograms/ml, respectively. These Cmaxs were concentrations yielding therapeutic effects in patients with acute asthma. Next, comparative pharmacokinetics between theophylline (Theodrip) and aminophylline were examined by a crossover method in 16 healthy volunteers (Ex II). The 90% confidence limits of the differences of mean values were within 80-120% and were 92.8-100.1% for Cmax, 99.7-105.3% for t1/2 and 100.2-104.4% for AUC. Thus, we concluded that the pharmacokinetics of the plasma theophylline after intravenous administration of Theodrip (theophylline at 4.8 mg/kg) were bioequivalent to those of aminophylline (6.0 mg/kg) for 30 min. In Ex I and II, no subjects had adverse effects and in Ex I no influence on ECG was seen. In addition, the convenience of Theodrip was compared with that of ampules of aminophylline among nurse volunteers (Ex III). The times required for set-up of Theodrip were significantly shorter than those of aminophylline ampules. On the other hand, the adverse reactions to aminophylline resulting from hypersensitivity reactions to its ethylenediamine component have been reported. Theodrip consists of 200 mg theophylline and 200 ml physiological saline in a plastic bag. Therefore, Theodrip, which does not contain ethylenediamine, is expected to have less adverse effects and be easier to handle than aminophylline.

Acute Disease↗
PubMed2000

Intracoronary serum smooth muscle myosin heavy chain levels following PTCA may predict restenosis.

Recently a novel biochemical method that uses an immunoassay to quantitate serum smooth muscle myosin heavy chain (SMMHC) levels was developed for diagnosis of aortic dissection.) The purpose of this study was to determine whether SMMHC released from the coronary arterial wall can be used to predict restenosis after percutaneous transluminal coronary angioplasty (PTCA). Fifty-two consecutive patients undergoing successful PTCA for single vessel disease were examined (40 men, 12 women, 63 +/- 8 years). Intracoronary blood samples were obtained distal to the lesion, and from the femoral artery after PTCA. In 10 patients, blood samples were taken immediately after the final balloon inflation, and 10 and 20 minutes after PTCA. SMMHC levels were measured by ELISA using SMMHC-specific monoclonal antibodies. Follow-up coronary angiography was performed 3 months after PTCA. Intracoronary serum SMMHC levels were significantly higher than those obtained from the femoral artery (10.6 +/- 1.5 vs 2.1 +/- 0.1 ng / ml, p < or = 0.001). Of 40 patients without apparent dissection, the 23 patients who did not develop restenosis in the follow-up study were found to have had higher levels of intracoronary SMMHC levels immediately after PTCA compared to the 17 patients with restenosis (15.2 +/- 2.9 vs 7.1 +/- 1.2 ng /ml, p < or = 0.05). We suggest that elevated intracoronary SMMHC levels after PTCA may reflect the extent of injury to the arterial wall. Intracoronary SMMHC may be a possible biochemical marker for the prediction of restenosis.

Aged↗
PubMed2000

Solitary fibrous tumor of the meninges in the posterior cranial fossa: magnetic resonance imaging and histological correlation--case report.

A 58-year-old female presented with a rare case of intracranial solitary fibrous tumor (SFT) manifesting as progressive ataxic gait and hearing loss on the left persisting for 6 months with recent symptoms of increased intracranial pressure. Computed tomography demonstrated a large isodense irregular-shaped mass in the left posterior cranial fossa. T2-weighted magnetic resonance imaging showed two components appearing as very low intensity and high intensity. Extreme-lateral suboccipital craniotomy was performed. Gross total resection was achieved except for some dural attachment in the jugular foramen. All symptoms and signs subsided after surgery. Histological, immunohistochemical, and electron microscopic examinations led to a diagnosis of SFT. The strongly hypointense areas on the T2-weighted images were hypocellular region characterized by disorganized spindle cells and thick bands of collagen. The hyperintense areas on the T2-weighted images were hypercellular region mimicking hemangiopericytoma. Strong immunoreactivity for CD34 was also helpful in the diagnosis. Electron microscopy revealed absence of pinocytic vesicles and dense laminae which are characteristic of hemangiopericytoma. The magnetic resonance imaging appearance of SFT seems to be pathognomonic.

Female↗
PubMed2000

Long-term prognosis of patients with ulcerative colitis in Japan.

Even though it is important in improving the quality of life to evaluate the long-term prognosis of patients with ulcerative colitis in comparison with the general population, it is unknown in detail. One hundred and seventeen cases followed-up for 10 years or more were evaluated to define the long-term prognosis of ulcerative colitis by the person-years method. The estimated number of death (E) was 14.5, and the observed number of death (O) was 20. The O/E ratio was 1.38 and confidence interval was 0.84-2.13, showing no significant difference between E and O. Evaluation of change in the O/E ratio at 5-year intervals revealed a decrease in both the males and females, with a significant difference observed between the ratios in 1960 and 1965 (each p < 0.05). Generally, the death rate was significantly higher in the patients with ulcerative clitis than in the general population between 1953 and 1965 but did not significantly differ thereafter. On the other hand, the E from malignant tumors was 3.94, and the O was 4; the O/E ratio was 1.02 and 95% confidence interval was 0.27-2.60, showing no significant difference between E and O.

Adolescent↗
PubMed2000

Cyclin E expression, a potential prognostic marker for non-small cell lung cancers.

Cyclin E is a G1 cyclin that has been shown to be one of the key regulators of the G1-S transition and could consequently be a deregulated molecule in tumors. In the present study, we have characterized cyclin E expression by immunohistochemistry in 217 resected non-small cell lung cancers (NSCLCs) and found large variations in cyclin E expression among tumors. High-level cyclin E expression (a cyclin E-labeling index > or =30%), observed in 115 (53%) of 217 NSCLCs, was more frequently found in tumors from smokers than from nonsmokers (P = 0.001), in squamous cell carcinomas than in nonsquamous cell carcinomas (P = 0.0002), and in pT2-4 tumors than in pT1 tumors (P = 0.04) by the chi2 test. Multivariate logistic regression analysis for the correlation between cyclin E expression and various characteristics showed a significant association of high-level cyclin E expression with squamous cell carcinomas (P = 0.005). Patients with tumors having high-level cyclin E expression survived a significantly shorter time than patients with tumors having low-level expression, both among the 151 patients with potentially curatively resected NSCLCs (5-year survival rates, 48 and 63%, respectively; P = 0.03) and the 103 patients with p stage I NSCLCs (5-year survival rates, 57 and 81%, respectively; P = 0.007). High-level cyclin E expression was also a significant and independent unfavorable prognostic factor in both patients with potentially curatively resected NSCLCs (P = 0.01) and in those with p stage I NSCLCs (P = 0.03) by Cox's proportional hazards model analysis. These findings indicate that cyclin E may play a pivotal role for the biological behavior of NSCLCs, and that a high level of cyclin E expression may be a new prognostic marker for NSCLCs.

Aged↗
PubMed2000

[Surgery for intrathoracic recurrence of non-small cell lung cancer].

In this study, we defined a solitary lung nodle in the same histology which could be traced its' origin from carcinoma in situ or was found over than two years' follow up as a second primary lung cancer. These cases were excluded. Eighteen cases underwent second surgery for intrathoracic recurrence. Fourteen cases were male and four cases were female. Their ages ranged from 23 to 75 (average 59.6) years. The histology were adenocarcinoma in 9 cases, squamouscarcinoma in 7, adenosquamous carcinoma in 1, large cell carcinoma in 1. The initial surgical procedures were lobectomy in 17, partial resection in 1. The initial stage were I in 13, II in 2, IIIA in 1. Pulmonary recurrence were found in 10, bronchial stump recurrence were found in 4, pulmonary hilus lymph node recurrence were found in 2, mediastinal lymph node recurrence were found in 2, pulmonary stump recurrence was found in 1. The second surgical procedures were completion pneumonectomy in 7, completion lobectomy in 1, lobectomy with segmentectomy in 1, segmentectomy or partial resection in 7, mediastinal dissection in 2. The overall 5-year survival rate of the patients with recurrence after reoperation was 31.8%. An aggressive surgical approach for recurrent lung cancer should be recommended.

Adult↗
PubMed2000

[Relationship between endothelial function and female hormone level in very old females: evaluation from ischemic reactive hyperemic response in forearm vessels].

Recently, the mechanism of longevity in females was proposed to be associated with female hormones. This study examined the effect of aging and sex on vascular endothelial function, and the relationship between female hormone level and endothelial function by ischemic reactive hyperemic response in the forearm using plethysmography. The study population consisted of 246 healthy subjects aged from 20 to 76 years (119 males, 127 females) and 20 healthy females aged 85 years and older (85 to 103 years; mean age 94 years) without distinct cardiovascular disease, hypertension, diabetes mellitus, renal disease, liver dysfunction or anemia. Levels of the female hormones, estradiol and estriol, were measured in females aged more than 85 years. The duration of reactive hyperemia decreased with aging, but the difference between males and females was not significant at any age. In females, the duration was markedly decreased from 110 +/- 36 sec in the fifties to 81 +/- 29 sec in the sixties or older (p < 0.05). Excess flow also showed similar changes to the duration of reactive hyperemia. The duration of reactive hyperemia and excess flow in females aged 85 years and older were similar to those in the fifties, but was significantly longer than those in females 60 years or older. The concentrations of estradiol (44.9 +/- 27.1 pg/ml) and estriol (22.1 +/- 13.4 pg/ml) in females aged 85 years were higher than in the sixties. There was a positive correlation between the duration of reactive hyperemia and the concentration of estradiol (r = 0.56, p < 0.01) or estriol (r = 0.57, p < 0.01). In summary, vascular endothelial function was impaired gradually with aging, but preservation of the function in healthy, very old females was closely associated with levels of female hormone.

Adult↗
PubMed2000

[Thallium-201 single photon emission tomography of intracranial angiomas].

We herein describe thallium-201 single photon emission tomography (T1-201 SPECT) findings in three cases with intracranial angioma. One of the lesions which was associated with chronic encapsulated intracerebral hematoma showed moderate accumulation of T1-201, but, others demonstrated no accumulation. The usefulness and limitations of T1-201 SPECT in differential diagnosis of intracranial mass lesions are discussed.

Adult↗