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Biomedical subjects

H Shiga

Publications and source records attributed to H Shiga.

At least 73 records · Page 4Linked to original sources
PubMed1992

[Psychosomatic medicine in rheumatoid arthritis].

Recent studies have shown that neuropeptides, such as substance P, are responsible for arthritis. We therefore studied opioid peptides (beta-endorphin, Methionine-enkephalin, Leucine-enkephalin) in order to confirm our belief that mental status may have some influence on the activity of rheumatoid arthritis (RA). We examined opioid peptides, lymphocyte subsets, psycologic test (Cornell Medical Index-Health questionnaire (CMI), the Face scale) and clinical data in patients with RA. Plasma Leu-enk, % Leu2a+ Leu15- cells,% Leu3a+ Leu8- cells and % Leu11+ Leu7- cells were higher in patients with a larger number of psycologic complaints in CMI. Plasma Leu-enk concentration was higher while % Leu11+ Leu7- cells was lower in proportion to the degree of neurosis, as indicated by the descrimitive chart of CMI. Plasma Met-enk concentration, % Leu2a+ Leu15- cells, and Lansbury's index were significantly higher in the group of patients whose facial expression was more severe. These findings suggest that mentala status have some relationship with the plasma level of opioid peptides (enkephalins) and immunologic functions, and that it may exert indirect effects on RA.

Arthritis, Rheumatoid↗
PubMed1991

Role of rectus muscle enlargement in clinical profile of dysthyroid ophthalmopathy.

Using logistic regression analysis, a correlation between enlargement patterns of the 4 rectus muscles and the occurrence of a variety of dysthyroid ophthalmopathy-associated ocular symptoms were analyzed in 698 eyes of 349 patients with this disorder. The condition of each rectus muscle was evaluated by computed tomography, and the various ocular symptoms were classified according to the Inoue classification system. The enlargement pattern, particularly when involving the inferior and medial recti, was found to have a strong statistical correlation with the occurrence of individual ocular symptoms. Additionally, the probabilities of the occurrence of most of the ocular symptoms were generally greater in those eyes with 2-, 3- or 4-muscle enlargement patterns than in those eyes with one or no enlarged rectus muscle.

Adult↗
PubMed1991

Antiarrhythmic and cardiovascular profiles of the fused indole compound (3aR,12R,12aR,12bS)-12-amino-2,3,3a,4,11,12,12a,12b-octahydro-10-hydrox yisoquino [2,1,8-lma]carbazol-5(1H)-one hydrochloride 1.5 hydrate.

Antiarrhythmic and cardiovascular profiles of a fused indole compound, (3aR,12R,12aR,12bS)-12-amino-2,3,3a,4,11,12,12a,12b -octahydro- 10-hydroxyisoquino [2,1,8-lma]carbazol-5(1H)-one hydrochloride 1.5 hydrate (RS-2135, CAS 133775-36-7), were investigated in anesthetized dogs. Class I antiarrhythmic agents such as disopyramide, lidocaine, mexiletine and flecainide were used as reference compounds. RS-2135 exerted more potent antiarrhythmic activity than reference compounds against ouabain-induced arrhythmias in dogs. The onset of action was slow, but the duration of action was longer than with the other compounds tested. The agent suppressed the conduction in the atrium, A-V node and ventricle more markedly than the reference compounds. RS-2135, however, did not change blood pressure and heart rate at a dose 5 times the dose for antiarrhythmic activity and decreased cardiac contractility to a lesser extent than the reference compounds.

Animals↗
PubMed1991

[Hemopurification in the management of ARDS complicating multiple organ failure].

In the field of critical care medicine, it has been claimed that ARDS often develops as a part of multiple organ failure (MOF). Since multi-modality therapy is necessary in the management of MOF, it is also mandatory even in the management of ARDS. Among the various therapeutic approaches for patients with MOF, hemopurification is one of the most effective therapeutic tools. Various hemopurification methods such as hemodialysis, peritoneal dialysis, hemoadsorption, hemofiltration and plasma exchange have been applied in the management of MOR. However, our recent experiences suggest that continuous hemofiltration (CHF) and/or continuous hemodiafiltration (CHDF) are safest, most easily performed and effective hemopurification in the management of ARDS/MOF. The efficacy of hemopurification in the management of ARDS is summarized as follows. 1) Removal of humoral mediators and causative substances of ARDS following insults such as sepsis and trauma. 2) Treatment of pulmonary interstitial permeability edema which has been claimed to be one of the most important pathological conditions in ARDS. 3) Removal of excess water given as carrier in IVH solution and accumulating in the body. 4) Immunomodulation which has also been considered to be necessary in the treatment or prevention of ARDS.

Hemofiltration↗
PubMed1991

The path of chewing movement before and after experimental occlusal interference.

To understand functions of the masticatory system accurate recording and analysis of mandibular movement are indispensable. The purpose of this experiment was to find functional differences in the path of masticatory movement due to experimental occlusal interference. Occlusal interference was placed on the mandibular first molar or cuspid of the habitual chewing side in seven normal subjects. While subjects were asked to masticate gum on one side at a time, jaw movements were recorded and analyzed using an automatic masticatory movement analysis system previously developed. Standard deviations (SD) of the vertical and lateral elements in the opening and closing phases were calculated and compared before and after the occlusal interference. In the opening phase the SDs increased significantly with either the interference placed on the cuspid or molar tooth. In the closing phase it generally increased with either the interference. The effect was significantly more with the cuspid interference than that of the molar tooth. The SD of the vertical element is also generally increased with either interference. However, in contrast to the lateral element, the effect of the molar interference on the vertical element was significantly more than that of the cuspid.

Adult↗
PubMed1990

Evidence for direct arrhythmogenic action of endothelin.

We studied electrophysiological effects of endothelin on canine cardiac tissues. Endothelin prolonged action potential duration and decreased spontaneous firing rate of the right bundle branch cells. At a concentration of 2 x 10(-7)M the plateau phase of action potentials was flattened, followed by the abrupt occurrence of early afterdepolarizations (EADs). ET, at a concentration as low as 2 x 10(-9)M, was capable of inducing EADs although their incidence was low. The EADs were initiated from the membrane potential less negative than -30mV and were suppressed by nicardipine, suggesting the involvement of dihydropyridine-sensitive Ca2+ channels in the induction of EADs. Because EADs are considered to underlie certain types of arrhythmias endothelin per se may have arrhythmogenic action.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1990

Hemodynamic changes following long-term administration of CS-905, a novel dihydropyridine calcium blocker, in conscious SHR.

To investigate the central and regional hemodynamics after long-term administration of CS-905, a novel calcium blocker, we administered the agent (1 and 3 mg/kg/day) for 15 weeks in spontaneously hypertensive rats. At the end of the dosing period, hemodynamic changes were examined using the radioactive microsphere technique. CS-905 produced a sustained dose-dependent antihypertensive effect without inducing tolerance during the 15-week dosing period and prevented cardiac hypertrophy. The agent increased cardiac output, decreased blood pressure and thus decreased total peripheral resistance in a dose-related manner. Regional blood flows measured by the microsphere technique were increased in the kidney and brain despite the lowered blood pressure. There was no organ where regional blood flow was decreased. These changes after chronic treatment with CS-905 would be beneficial in the long-term therapy of hypertension.

Animals↗
PubMed1989

[Magnetic resonance imaging of bladder tumors: superiority of serial "Fast SE" assisted by Gd-DTPA in tumor staging].

Eighteen cases with bladder tumors were examined by means of superconducting MRI. Sequences used were spin echo (TR/TE (msec) = 500/20 as T1WI (weighted image) and 1500/80 as T2WI) and serial "fast spin echo (fast SE)" pre/post Gd-DTPA administration. "Fast SE" was a new technique offering a distinct T1WI (TR/TE = 100/14, utilizing a 14 second breath hold). Slice thickness of "fast SE" was 10 mm and slice plane was selected perpendicular to the tumor base to detect the extent of invasion. Serial scan of "fast SE" was performed before and immediately after 0.1 mmol/kg Gd administration. Scanning was completed before the bladder was opacified by Gd. Tumor and normal mucosa were both markedly enhanced whereas the surrounding muscle layer remained hypointense. On delayed scan, the elevated character of the tumor was outlined by opacified urine but the distinction between the mucosa and the muscle layer became unclear. Total cystectomy (TC) was performed in 6 of 18 cases and pathological tumor extension was correlated with MR findings. Transurethral resection (TUR) was performed in the remaining 12 patients, and the tumor extension was assessed by follow-up biopsy after TUR. Intact liner hypointensity indicated superficial lesions (= less than pT2), while disruption of the linear hypointensity corresponded pathologically to deep muscle invasion (= greater than pT3a). Accuracy of serial "fast SE" in tumor staging was 94% (17/18). Serial "fast SE" allowed the distinction of superficial from invasive tumors more accurately than conventional studies, and therefore assisted in choosing the correct operative method.

Adult↗
PubMed1989

Arterial and venous vasodilator actions of RS-1893, a novel cardiotonic agent, in the hindlimb preparation of the dog.

RS-1893, an orally active cardiotonic agent, has been suggested to dilate venous blood vessels, because it markedly decreases central venous pressure in anesthetized dogs. In order to evaluate venous vasodilator action of the agent, we measured hindlimb volume (HLV) in anesthetized dogs using a plethysmographic technique. RS-1893 (1-10 micrograms/kg, i.v.) produced dose-dependent increases in HLV, femoral blood flow, and left ventricular (LV)dP/dt, and a decrease in central venous pressure (CVP). In another series of experiments, we autoperfused the hindlimb with a constant flow and injected the drugs intraarterially (i.a.) to separately evaluate arterial and venous vasodilator actions. In this preparation, a decrease in perfusion pressure and an increase in HLV were considered to reflect arterial vasodilatation and venous vasodilatation, respectively. RS-1893 (0.3-3 micrograms i.a.) produced a dose-dependent increase in HLV and a decrease in perfusion pressure. Comparison of doses which increased HLV by 0.3 ml revealed that RS-1893 was about 20 times more potent than milrinone. The arterial vasodilator action of RS-1893 was about 15 times more potent than that of milrinone. We conclude that RS-1893 is a potent venous and arterial vasodilator with cardiotonic activity.

Animals↗
PubMed1989

Effects of RS-1893, a novel cardiotonic agent, on central and peripheral hemodynamics in anesthetized rats.

After the use of two radionuclides in the tracer microspheres technique in the rat was verified, we examined the central and peripheral hemodynamic effects of RS-1893, an orally active cardiotonic agent. An intravenous infusion of RS-1893 at a dose of 3 micrograms/kg/min gradually decreased blood pressure and increased heart rate and cardiac output. Blood flows in the kidney and stomach were increased. There was no organ in which blood flow was decreased despite the fall in blood pressure. These data suggest that RS-1893 dilates blood vessels in the whole body, especially in the kidney and stomach.

Anesthesia↗
PubMed1989

[Cellular metabolic consideration in the pathophysiology and the treatment of shock].

Shock is defined as the summation of cellular dysfunction and resultant impairment of the function in various organs. The typical such condition can be observed in shock-induced multiple organ failure (MOF). Therefore, the most effective and fundamental management against shock should be the improvement of such cellular dysfunction. The present study was undertaken to investigate the cellular metabolic abnormalities and their treatment in shock-induced MOF patients. The severity of cellular damage was evaluated with cellular injury score (CIS), which can be calculated by scoring the values of osmolality gap, arterial ketone body ratio and blood lactate. The CIS correlated significantly with the outcome and the number of failing organs in the MOF patients. Since tissue hypoxia and humoral mediator have been considered to play a key role in the development of such cellular dysfunction, protease inhibitor was administered to such patients and oxygen metabolism was improved with catecholamine. The CIS improved among survived MOF patients following those treatments. These results suggest that the shock-induced MOF is the summation of the cellular dysfunction which can be assessed with the CIS, and that such cellular dysfunction could be improved through the therapeutic approach to the humoral mediators and/or tissue oxygen metabolism.

Humans↗
PubMed1989

[Xenon-enhanced CT CBF measurements in intracranial vascular malformations].

In the management of intracranial vascular malformations, it is important to know the regional cerebral blood flow in its surrounding structure. However, CT scan with contrast medium and angiography have only a limited ability to estimate the rCBF. In this study, stable xenon-computerized tomography scanning by means of the end-tidal gas-sampling method was performed in eleven patients with intracranial vascular malformations. Seven of the patients had arteriovenous malformations, three had venous angiomas and one had aneurysm of the vein of Galen. In two patients with large arteriovenous malformations, in two with "larger" venous angioma and in one with aneurysm of the vein of Galen, rCBF values were significantly reduced, particularly adjacent to the malformations. In contrast, there were no areas showing reduced rCBF in cases where the malformations were small. This indicates development of ischemia correlates with the size of malformations. From the xenon-enhanced CT scan and angiographic findings, the presence of steal phenomenon with venous congestion might be a cause of rCBF reduction in those cases where ischemia exists.

Adolescent↗
PubMed1988

Cardiovascular pharmacology of RS-1893, an orally active cardiotonic agent with arterial and venous vasodilator actions.

RS-1893, 2-[2-chloro-4-(2,3,4,5-tetrahydro-3-oxo-6-pyridazinyl)]-phenoxy-N- (2-(2-morpholinoethyl)-acetamide, is a newly synthesized compound whose structure is different from that of cardiac glycosides and beta-stimulants. The in vitro cardiotonic action of RS-1893 was about 3 times more potent than that of milrinone. This action is most likely due to inhibition of phosphodiesterase-III, as has been suggested for many other cardiotonic agents. In pentobarbital anesthetized dogs, RS-1893 (1-30 micrograms/kg, i.v.) produced dose dependent increases in left ventricular dP/dtmax and cardiac output and caused decreases in blood pressure and total peripheral resistance with a relatively small increase in heart rate. Central venous pressure decreased markedly, suggesting venous vasodilation. The in vivo cardiotonic action of RS-1893 was 3 times more potent than that of milrinone and was not affected in the presence of a large dose of propranolol. Oral administration of RS-1893 (0.03 and 0.1 mg/kg) also produced a dose-related increase in cardiac contractility in conscious beagles. The increase in LVdP/dtmax reached a maximum in 1-3 hr after administration and lasted for more than 8 hr. Thus, RS-1893 appeared to be an orally active cardiotonic agent with vasodilator properties, probably acting on both arterioles and veins.

3',5'-Cyclic-AMP Phosphodiesterases↗