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Biomedical subjects

Y Katsuta

Publications and source records attributed to Y Katsuta.

At least 19 recordsLinked to original sources
PubMed2001

[Pulmonary hypertension complicating portal hypertension: portopulmonary hypertension].

Portopulmonary hypertension is a condition with a poor prognosis, which is defined as precapillary pulmonary hypertension complicating portal hypertension mainly due to cirrhosis of various etiologies. A mean pulmonary arterial pressure greater than 25 mmHg at rest with a pulmonary capillary wedge pressure less than 15 mmHg and a pulmonary vascular resistance greater than 120 dynes.sec.cm-5, in the setting of the presence of portosystemic shunting has been proposed as hemodynamic criteria for portopulmonary hypertension. Prevalence of pulmonary hypertension ascertained by right cardiac catheterization was 2% among patients with cirrhosis, and reached to 4% particularly among candidates for liver transplantation. Hyperdynamic systemic circulation seen commonly in patients with cirrhosis appeared to be normalized by complication of pulmonary hypertension with a contraction of circulating plasma volume. Long term treatment by epoprostenol administration or nitric oxide inhalation could induce a gradual decline in pulmonary arterial pressure in patients with poor response to acute vasodilator administration.

Adolescent↗
PubMed2000

A variant form of Churg-Strauss syndrome: initial temporal non-giant cell arteritis followed by asthma--is this a distinct clinicopathologic entity?

The clinical manifestations of the classical vasculitis syndromes are extraordinarily heterogenous with considerable overlap among them. Recently, several cases of unusual presentation of the vasculitis syndromes have been reported. We describe a patient who initially manifested with temporal arteritis and Raynaud's phenomenon and subsequently developed bronchial asthma, ie, a case of an atypical form of Churg-Strauss syndrome (allergic angiitis and granulomatosis) and discuss whether this case is a distinct clinicopathological entity.

Adult↗
PubMed2000

Detection and elimination of contaminating microorganisms in transplantable tumors and cell lines.

As a quarantine of biological materials, we tested 96 transplantable tumors and cell lines for contamination with microorganisms in a mouse antibody production (MAP) test, enzymatic assay and microbiological culture. Contamination with lactic dehydrogenase elevating virus (LDV), mycoplasmas and Pasteurella pneumotropica was detected. A considerable difference in the contamination rate was observed between in vivo- and in vitro- propagated tumors. LDV in the tumors could be eliminated by both in vitro subculture and subpassage in nude rats. Mycoplasmas were eliminated by means of the mycoplasma-removal agent and P. pneumotropica by subpassage in mice. These results suggest that there is still a high risk of contamination in transplantable tumors and emphasizes the importance of adequate microbiological quality control.

Animals↗
PubMed1997

Effects of the alpha-/beta-blocking agent carvedilol on hepatic and systemic hemodynamics in patients with cirrhosis and portal hypertension.

To enhance the portal hypotensive effect of nonselective beta-blockers, combinations of vasoactive agents with different mechanisms should be considered. The effect of carvedilol (CAS 72956-09-3, Artist), and alpha-/beta-blocking agent, on hepatic and systemic hemodynamics in 10 patients with portal hypertension was evaluated. After administration of carvedilol, the hepatic venous pressure gradient (HVPG) decreased from 15.9 +/- 3.2 mmHg to 13.3 +/- 4.0 mmHg (mean +/- SD) at 60 min (-15%) and to 12.9 +/- 3.0 mmHg at 90 min (-17%, p < 0.05). However, only 5 patients showed a decrease of HVPG by more than 20% at 60 or 90 min. The estimated hepatic blood flow (EHBF) was not significantly reduced. In contrast, heart rate (-8%, p < 0.05), mean arterial pressure (-10%, p < 0.01), and cardiac index (CI) (-8%, p < 0.05) were all reduced at 90 min, while total systemic vascular resistance was not altered. The reduction of HVPG was significantly correlated with the decrease of CI (r = 0.6415, p < 0.05). The portal hypotensive effect of carvedilol may mainly result from a reduction of CI. However, because of the greater reduction of HVPG than that of CI, other additive actions were suggested.

Adrenergic alpha-Antagonists↗
PubMed1996

Structure around C6-C7 bond of the chromophore in bathorhodopsin: low-temperature spectroscopy of 6s-cis-locked bicyclic rhodopsin analogs.

To elucidate the structural changes near the beta-ionone ring region of the chromophore during the photobleaching process of rhodopsin, the photochemical and subsequent thermal reactions of rhodopsin analogs, whose retinylidene chromophores were fixed in a 6s-cis form with a five-membered ring (6,5-rhodopsin) and a seven-membered ring (6,7-rhodopsin), respectively, were investigated by low-temperature spectroscopy. Like rhodopsin, both the rhodopsin analogs convert to the respective batho-intermediates upon absorption of light at -190 degrees C. The extinction coefficient of batho-intermediate of 6,5-rhodopsin is similar to that of bathorhodopsin, while that of 6,7-rhodopsin is considerably smaller than that of bathorhodopsin. Like bathorhodopsin, the batho-intermediate of 6,5-rhodopsin directly converts to lumi-intermediate, while that of 6,7-rhodopsin first converts to a blue-shifted intermediate and then to lumi-intermediate. These results strongly suggest that the structure around the beta-ionone ring region of the bathorhodopsin chromophore resembles 6,5-retinal rather than 6,7-retinal. From the comparison of the structural features among retinal, 6,5-retinal, and 6,7-retinal, a possible conformation around C6-C7 bond of the bathorhodopsin chromophore is discussed.

Animals↗
PubMed1996

Advantages and safety of local treatment with MMC/Beriplast P for cancer tumors.

To target the treatment of small points of cancer, Beriplast P, already used clinically as a physiological tissue adherent drug carrier, was mixed with the anticancer drug, mitomycin C (MMC). In this in vitro study, MMC did not release quickly from the clot of MMC/Beriplast P. The antitumor effect of this mixture was examined for its effect on cancer growth. In one series of experiments, tumor tissues were inoculated with MMC/100 microliters Beriplast P and in another series, MMC/100 microliters Beriplast P was injected into tumors at a weight of 300 mg. In the first series of experiments, tumor tissue treated with 0.3 mg MMC/100 microliters Beriplast P was replaced with plasma cells and lymphocytes, and no viable cancer cells could be found. In the second series, MMC/100 microliters Beriplast P delayed tumor growth, and the survival of Balb/c mice injected with 0.08 mg MMC/100 microliters Beriplast P was significantly longer than that of mice injected with 0.08 mg MMC/100 microliters saline solution (P = 0.026). In addition, the abdominal aorta, vena cava, and intestine around the area of treatment with 1.6 mg MMC/100 microliters Beriplast P were not damaged. These results indicate that the mixture of Beriplast P and MMC is more effective than MMC solution alone in the local treatment of residual cancer.

Animals↗
PubMed1996

Papillary and follicular thyroid carcinoma: the treatment results of 357 patients at the National Kyushu Cancer Centre of Japan.

During the period from April 1974 to March 1993, 357 patients received surgical treatment for papillary and follicular carcinoma of the thyroid gland at the Department of Head and Neck Surgery of National Kyushu Cancer Centre, Japan. In this paper, we review the various clinico-pathological features of these patients and analyse their influence on patient survival. While the majority of the patients' ages ranged from the third through seventh decade, only the patients older than 40 years old died. In papillary carcinomas, there was a statistically significant difference in the survival rate between younger (less than 45 years old) and older (45 years of age or older) patients. The rate of patients who died of thyroid cancer also increased in the cases with extra-thyroidal tumour invasion, and metastasis to distant organs. A multivariate analysis also showed that the age, extrathyroidal invasion and distant metastasis are significant prognostic factors. However, sex, histology and lymph node metastasis were not prognostic factors for survival.

Adenocarcinoma, Follicular↗
PubMed1995

Portal and systemic hemodynamic responses to a very low dose of nitroglycerin in cirrhotic patients with portal hypertension.

Portal and systemic hemodynamic responses to a very low dose of nitroglycerin were studied in patients with portal hypertension and cirrhosis, and compared with those to a high dose of this compound. A 0.15 mg dose of nitroglycerin was given sublingually to 10 patients (LDG), and 0.3 mg to another 10 (HDG). Hemodynamic measurements were performed by means of hepatic venous and right cardiac catheterization before and 5 min after nitroglycerin administration. The wedged hepatic venous pressure decreased after dosing by 7.9% (p < 0.01) in LDG, and by 15.3% (p < 0.01) in HDG. Hepatic blood flow with ICG did not change in either group. In LDG, azygos blood flow remained unchanged, in contrast to a significant decrease by 10.1% (p < 0.05) in HDG. Mean arterial pressure fell by 3.6% (p < 0.05) in LDG and by 18.6% (p < 0.01) in HDG. Cardiac index did not change in LDG, but decreased by 11.4% (p < 0.05) in HDG. In both groups, mean pulmonary arterial pressure and pulmonary capillary wedge pressure fell significantly by the same amount. In HDG, a significant correlation between changes in wedged hepatic venous pressure and azygos blood flow (r = 0.70, p < 0.05) was observed. This suggested that splanchnic vasoconstriction mediated by a high-pressure, rather than a low-pressure, baroreceptor reflex was the main contributor to a decrease in portal venous blood flow, resulting in a reduction in wedged hepatic venous pressure; whereas a slight but significant fall of wedged hepatic venous pressure induced by a very low dose of nitroglycerin might have been due to venodilatation in the portal system and the hepatic vascular bed. These data suggest that, even with a very low dose of nitroglycerin, partial improvement of the hepatic circulation can be expected with minimal change in the systemic circulation in patients with cirrhosis and portal hypertension.

Female↗
PubMed1994

Flies in the group Cyclorrhapha use (3S)-3-hydroxyretinal as a unique visual pigment chromophore.

In the class Insecta, retinal and 3-hydroxyretinal are used as chromophores of visual pigments, but the absolute structure of the 3-hydroxyretinal chromophore has yet to be clarified. This study investigates the chirality of 3-hydroxyretinal in the compound eyes of five representative orders of insects. In the orders Odonata, Hemiptera, Neuroptera and Lepidoptera, and suborders Nematocera and Brachycera of the Diptera, only (3R)-3-hydroxyretinal isomers were detected, but dipterans of the suborder Cyclorrhapha (higher flies) had the (3S)-11-cis enantiomer and a mixture of (3R)-all-trans and (3S)-all-trans 3-hydroxyretinal enantiomers; the ratio of the (3R) enantiomer to the sum of both enantiomers of the all-trans isomer was in the range 9-32%. Despite differences in feeding habits, including one species that is a butterfly parasite, all higher flies analysed to date share the same pattern of 3-hydroxyretinal enantiomers, making them a unique group with regard to the nature of the visual pigment chromophore.

Animals↗
PubMed1994

Effect of long-term therapy with nipradilol on esophageal varices in patients with compensated cirrhosis. Results of a multicenter open study.

The effect of long-term administration of nipradilol (NIP, Hypadil Kowa, CAS 81486-22-8), a beta-blocker with a vasodilatory action, on esophageal varices was studied in 66 patients with compensated liver cirrhosis. Administration of NIP (6-12 mg/d) for 3-12 months produced progressive improvement of endoscopic findings over time (30% for C, 25% for F, and 40% for the R-C sign after 12 months). At the last examination (mean: 9 +/- 4 months), the improvement rates were 16.7%, 16.7% and 22.7%, respectively. No significant relationship was found between endoscopic improvement and the Child-Pugh score or the dose of NIP. Gastrointestinal bleeding occurred in five patients: one had bleeding esophageal varices, three had bleeding gastric varices, and one had a bleeding gastric ulcer. The systolic blood pressure was decreased significantly (4.6-12.3%) at 2 weeks as well as 1 and 2 months, and the heart rate showed a significant decrease throughout the study (10-18.4%). With the exception of the patients who had gastrointestinal bleeding, no symptoms of decompensation appeared, and there was no deterioration of laboratory parameters including ammonia. Adverse effects occurred in about 10% of the patients, most of which were related to bradycardia and/or hypotension, and they improved when the drug was withdrawn or the dose reduced. These results suggest that long-term administration of NIP is useful in the treatment of esophageal varices.

Adult↗
PubMed1993

Steric constraints in the retinal binding pocket of sensory rhodopsin I.

Steric constraints in the retinal binding pocket of sensory rhodopsin I (SR-I) are analyzed by studying effects of sample temperature and retinal analogs. The flash-induced yield of the earliest detected intermediate S610, which corresponds to the K intermediate in the bacteriorhodopsin (BR) photocycle, decreases below 220 K and reaches zero at 100 K, while K formation is independent of temperature. The reduced S610 formation at low temperatures indicates a more restricted retinal binding pocket in SR-I during primary photochemical events. Introduction of bulky substituents on the retinal polyene chain in four retinal analogs greatly retards or blocks the final step of chromophore binding to the apoprotein of SR-I. Except for the 14-methyl substitution, these modifications exhibit little or no effect on chromophore binding to BR apoprotein. These results corroborate that the retinal polyene chain binding domain in SR-I is more sterically constrained than that of the retinal pocket in BR. Deletion of the beta-ionone ring renders the analog SR-I pigments nonfunctional, as does deletion of the 13-methyl group, but the corresponding BR analogs are both photochemically and physiologically active. In contrast to the corresponding BR analog, photolysis of the analog SR-I reconstituted with 13-desmethylretinal does not produce an S610-like intermediate at room temperature. The above results and the previous findings that protein constraints inhibit the accommodation of a stable 13-cis-retinal configuration in SR-I suggest a model in which the 13-methyl group functions as a fulcrum to permit movement of one or both ends of retinal to overcome an energy barrier against isomerization.

Bacteriorhodopsins↗
PubMed1993

Plasma volume contraction in portal hypertension.

The effect of blood volume contraction induced by a 4-week regimen of spironolactone (100 mg/day) or furosemide (40 mg/day) on the hepatic venous pressure gradient (HVPG), an indicator of portal hypertension, was evaluated in patients with cirrhosis and no ascites. In the spironolactone group (n = 15), HVPG decreased significantly from 16.5 +/- 0.9 mmHg (mean +/- S.E.M.) to 12.9 +/- 1.0 mmHg (P < 0.005) and total blood volume contracted significantly from 4338 +/- 231 ml to 4006 +/- 203 ml (n = 14, P < 0.01). Although the HVPG changes did not correlate significantly with changes in measured total blood volume or in simultaneously determined systemic haemodynamics, a significant inverse correlation (r = -0.74, P < 0.01, n = 12) was found between the HVPG change and posttreatment plasma aldosterone levels, attesting to the effectiveness of spironolactone therapy in lowering HVPG. In the furosemide group (n = 10), neither HVPG (13.7 +/- 0.3 mmHg vs. 13.6 +/- 0.9 mmHg) nor total blood volume (4961 +/- 153 ml vs. 4964 +/- 162 ml) declined significantly. These results show that long-term administration of spironolactone to patients with cirrhosis and no ascites produced a significant reduction in HVPG that may have been due to gradual, sustained volume contraction. Thus, spironolactone may prove to be an effective treatment for portal hypertension in cirrhosis without ascites.

Aged↗
PubMed1993

The conformational analysis and photoisomerization of retinochrome analogs with polyenals.

3,7-Dimethyl-2,4,6,8,10-dodecapentaenal was synthesized for reconstitution of the retinochrome analog. Its opsin shift was 1000 cm-1 smaller than that of native retinochrome, whose chromophore contains the same number of double bonds. The conformational change from 6-s-trans to 6-s-cis, as figured in a retinal molecule, plays an important role in the formation of the retinochrome analog, based on the estimation of opsin shifts for retinal analogs locked in the 6-s conformation. Thus the conformation of the 6-7 single bond in the native retinochrome was suggested to be 6-s-cis. Analysis of the circular dichroic spectra of retinochrome analogs revealed that the 6-s conformation is independent of the appearance of the beta-band. The stereoselectivity in the photoisomerization of the retinal analogs by a retinochrome template depends on the hydrophobic binding in the region of the beta-ionone ring.

Circular Dichroism↗
PubMed1993

[Synthesis and antiulcer effects of 5-hydroxy-4-[2-substituted-(E)-ethenyl]-2(5H)-furanone. (1)].

gamma-Hydroxybutenolides possessing conjugated substituents at the beta-position and their related compounds have been synthesized by the previously reported procedure with minor modifications and their antiulcer activities have been examined in the HCl-ethanol induced ulcer model often used for the evaluation of gastric mucosal protective factor enhancing effect. The compound A-1 5-hydroxy-4-[2-(2,6,6-trimethyl-1-cycohexenyl-1-yl)-(E)-ethenyl]-2 (5H)-furanone showed a pronounced effect at a low dosage of 5 mg/kg p.o. and some analogues compounds also exhibited potent inhibitory activity as compared with the reference drugs. The relationship between the structure of gamma-hydroxybutenolides and the antiulcer effect has been also examined and then the 5-hydroxyl group has been found to be essentially functional one to have antiulcer activity.

4-Butyrolactone↗