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Biomedical subjects

S Nishimura

Publications and source records attributed to S Nishimura.

At least 631 records · Page 35Linked to original sources
PubMed1988

Ratio judgments of empty durations with numeric scales.

A study is reported on the perception of empty time intervals marked by auditory signals. Nakajima's supplement hypothesis, which states that the subjective duration of a subjectively empty time interval is proportional to its physical duration plus a constant of approximately 80 ms, was examined quantitatively. Although this hypothesis has been used to explain various general aspects of time perception, from a global viewpoint, it has lacked the quantitative data necessary to describe the shape of the psychophysical functions mathematically. In the present study, subjects used two positive numbers to estimate the subjective ratio (m:n) between the durations of two serial or separate empty intervals. The psychophysical functions for empty durations 50-600 ms long could be approximated by a straight line with a positive gamma-intercept, as predicted by the hypothesis. The effective range of the hypothesis could be extended to approximately 1200 ms. A power function (without any modifications) also gave good approximations. The reliability and validity of the supplement hypothesis are discussed.

Adult↗
PubMed1988

Close correlation between restriction fragment length polymorphism of the L-MYC gene and metastasis of human lung cancer to the lymph nodes and other organs.

Restriction length fragment polymorphism of the L-MYC gene was examined in DNAs from lung cancer tissues and normal tissues of 51 Japanese patients with lung cancer. In individual patients, no difference was seen between the restriction length fragments of the two alleles of L-MYC [6-kilobase (kb) and 10-kb fragments in EcoRI digests] in lung cancer tissues and normal tissues. But a striking correlation was found between the restriction length fragment polymorphism pattern of L-MYC and the extent of metastasis, particularly to the lymph nodes at the time of surgery: Patients with only the L band (10 kb) had few lymph node metastatic lesions, whereas patients with either the S band (6 kb) or the S and L bands almost always had lymph node metastatic lesion. A similar correlation was found between the presence of the S band and metastases to other organs. This correlation was particularly marked in cases of adenocarcinoma. These results indicate a clear genetic influence on metastases and a consequent poor prognosis for certain patients of lung cancer; L-MYC restriction length fragment polymorphism is thus shown to be a useful marker for predicting the metastatic potential of human lung cancer.

Adult↗
PubMed1988

Effects of electrical stimulation on intracranial pressure and systemic arterial blood pressure in cats. Part I: Stimulation of brain stem.

It has been suggested that brain stem activity is involved in the occurrence of pressure waves. Different sites in the brain stem were activated by electrical stimulation in cats anaesthetized with sodium pentobarbital, to produce an increase in intracranial pressure (ICP) similar to the pressure waves. Then the effect of artificial ventilation on the occurrence of the pressure wave-like response produced under spontaneous respiration was examined since Lundberg's A-waves appear even in artificial ventilation, and B-waves are effaced during artificial ventilation. This results in a brain stem map of ICP and systemic arterial blood pressure (BP) produced by electrical stimulation during spontaneous respiration. Stimulation of the rostral medullary reticular formation produced a rise in ICP and BP in association with a change in the rhythm of the spontaneous respiration; with artificial ventilation, stimulation produced a rise in BP but ICP kept almost at the same level. However, the rise in ICP that was produced by stimulation of the caudal medullary reticular formation during spontaneous respiration also occurred with a depressor response of BP during controlled ventilation. The pressure wave-like responses could be classified, therefore, into two types. One was the response seen during both spontaneous and controlled ventilation, which we designated the 'alpha' wave. The other was the response seen only during spontaneous ventilation, the 'beta' wave. These observations suggest that the origins of A- and B-waves may be related to those of 'alpha' and 'beta' waves, respectively.

Animals↗
PubMed1988

Effects of electrical stimulation on intracranial pressure and systemic arterial blood pressure in cats. Part II: Stimulation of cerebral cortex and hypothalamus.

This experimental work was carried out to examine whether activation of autonomic cortical and hypothalamic areas by electrical stimulation is related to changes in the intracranial pressure (ICP) in cats anaesthetized lightly with sodium pentobarbital. Electrical stimulation was performed using a concentric electrode with a train of electrical pulses (pulse duration, 0.4 ms; frequency, 40 Hz; intensity, 50-400 microA). Stimulation of sites in the anterior cingulate gyrus produced a rise in ICP associated with a fall in systemic arterial blood pressure (BP) or with no change in BP. Stimulation of sites in the anterior hypothalamus produced a fall in BP with an increase in ICP. Stimulation of sites in the area extending from the anterior hypothalamus to the posterior hypothalamus produced rises in BP and ICP. These observations suggest that activation of autonomic cortical and hypothalamic areas is involved in changes in ICP.

Animals↗
PubMed1988

Inhibition of expression of natural UAG suppressor glutamine tRNA in HIV-infected human H9 cells in vitro by Avarol.

HTLV-IIIB-infected H9 cells are shown to contain a high level of the natural UAG suppressor glutamine tRNA(UmUG Gln); this tRNA has been demonstrated to be required for the synthesis of Moloney murine leukemia virus (Mo-MuLV)-encoded protease. After cultivation of HTLV-IIIB-infected H9 cells with Avarol at a concentration (1 microgram/ml), previously found to protect the cells against the cytopathic effects of HTLV-III, an almost complete inhibition of the synthesis of the tRNA(UmUG Gln) was observed. Moreover, we obtained some evidence that the processing of the HTLV-III precursor protein p53 to p24 is inhibited by Avarol in infected cells, suggesting that the compound interferes with the expression of the viral protease gene.

Animals↗
PubMed1988

Conversion of the guanine nucleotide binding sites of ras protein resulting in the reduction of base specificity.

A gene coding for the novel ras protein, p21X, in which the domains of guanine binding and phosphate binding were exchanged, was constructed and expressed in Escherichia coli. The gene product, p21X, showed GTP binding activity, but no GPTase activity. In addition, p21X revealed binding activity toward ATP and CTP. In a competitive binding assay, [3H]GTP binding to p21X was inhibited in the presence of ATP, CTP and UTP, ITP as well as GDP, GTP and dGTP.

Amino Acid Sequence↗
PubMed1988

Mechanism of hematuria. II. A scanning electron microscopic demonstration of the passage of blood cells through a glomerular capillary wall in rabbit Masugi nephritis.

A model of hematuria was established in rabbits. An accelerated form of unilateral Masugi nephritis was induced in 10 New Zealand white rabbits by an intravenous injection of duck antirabbit kidney serum and by ligating the left renal artery immediately after the injection of the antibody. All 10 rabbits became hematuric 1-2 weeks after the injection of the antibody and red blood cell (RBC) casts were found in the urinary sediment of all these animals. An ultrastructural examination of renal glomeruli by transmission electron microscopy revealed the transcapillary passage of polymorphonuclear leukocytes through the gaps of the glomerular basement membrane (GBM). RBC were found in the urinary space in 50% of the glomeruli observed by scanning electron microscopy (SEM) and the passage of leukocytes and RBCs through the glomerular capillary wall was also observed. Gaps in the GBM became clearer after the removal of cellular components by detergents. In control rabbits, no RBCs could be observed in the urinary space, and isolated GBM were intact by SEM. These data further support the hypothesis that in rabbit Masugi nephritis hematuria is a result of the passage of RBCs through gaps in the GBM.

Animals↗
PubMed1988

Disseminated intravascular coagulation accompanying thoracic and abdominal aortic aneurysm; report of three cases.

We reported three patients who developed disseminated intravascular coagulation (DIC) accompanying thoracic and abdominal aortic aneurysm. The first case, a 26-year-old man with dissecting aortic aneurysm developed DIC with clinical bleeding after operating on glaucoma. The administration of fibrinogen concentrates and antifibrinolytic agent made his DIC improve. The second case, a 70-year-old man with abdominal aortic aneurysm developed DIC showing large ecchymosis after angiography. His DIC disappeared after operation on aneurysm. The third case, a 73-year-old woman with thoracic and abdominal aneurysm developed laboratory-DIC without severe hemorrhagic diathesis. During antifibrinolytic therapy, platelet count, fibrinogen and fibrinogen degradation product (FDP) level improved. Since the treatment of the coagulopathy might be varied in the situation of the cause and clinical course, it is noted that anti-fibrinolytic therapy was effective in our two cases.

Adult↗
PubMed1988

Fluoroaluminates stimulate histamine secretion in the digitonin-permeabilized rat mast cells.

The combination of NaF and AlCl3 stimulated histamine secretion from digitonin-permeabilized rat mast cells only in the presence of trace amount of Ca2+. When NaF plus AlCl3 were added together with a maximal dose of guanosine-5'-[gamma-thio]triphosphate (GTP gamma S), the combined effect was less than additive. The results suggest that the secretory effect of fluoroaluminates is, at least partially, mediated by GTP-binding protein, which is previously found to be activated by GTP gamma S.

Aluminum↗
PubMed1988

Mechanisms of potentiation of antitumor activity of 5-fluoro-2'-deoxyuridine in the adenocarcinoma 755 system by guanosine 5'-monophosphate.

The effect of guanosine 5'-monophosphate (GMP) on the antitumor activity of 5-fluoro-2'-deoxyuridine (FdUrd) was investigated by using a solid tumor, adenocarcinoma 755. FdUrd only slightly inhibited the tumor growth even at the maximum tolerated dos (ILS,6%). GMP at 300 mg/kg/day markedly potentiated the inhibition of tumor growth by FdUrd (ILS, 61%). When tumor-bearing mice were treated with the combination of 3H-FdUrd and GMP, 3H-FdUrd was significantly incorporated into tumor RNA as compared to the mice not given GMP, although the 5-fluoro-2'-deoxyuridine 5'-monophosphate (FdUMP) level in the tumor in the combination with GMP was decreased. The increased incorporation of 3H-FdUrd into RNA ([FUra]RNA) of the tumor was due to an increased level of FUra in plasma and tumor. On the other hand, incorporation of 3H-FdUrd into the RNA of the small intestine, which is one of main target tissues of FUra toxicity, was not increased. Thus, the potentiating effect of GMP on the antitumor activity of FdUrd is apparently due to the specifically increased FdUrd and FUra levels in the tumor. The combination with GMP caused marked incorporation of 3H-FdUrd into RNA in the tumor but uptake of 3H-FdUrd into RNA in the small intestine was not increased. These results suggest that GMP can potentiate the antitumor activity of FdUrd without increasing gastro-intestinal toxicity.

Adenocarcinoma↗
PubMed1988

Two-dimensional NMR analyses of dynamic structures of tRNA and the regulation of codon recognition by post-transcriptional modifications.

By two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy, we analyzed dynamic structures of various tRNA species from Escherichia coli and Bacillus subtilis. Proton resonances due to the anticodon of the tRNA molecules were unambiguously identified by NOESY and 2D-HOHAHA techniques. Thus, it was found that rigidity/flexibility of the two types of modified uridines in the first position of the anticodon were certainly related with the codon recognition properties of the tRNA species.

Anticodon↗
PubMed1988

[Progression of coronary artery stenosis and compensatory development of collaterals: analysis of data of 25 patients who developed complete occlusion].

The correlation between progression of atherosclerotic lesions and the compensatory development of collaterals which prevent ischemic events, particularly myocardial infarction, were examined in patients who underwent repeated coronary angiography (CAG) after medical therapy. Twenty-five patients with lesions in their coronary arteries perfusing the viable myocardium during the first study, which progressed to total occlusion in the second study, were evaluated. The subjects' mean age was 55.1 years, and the mean time interval between the two studies was 44.1 months. CAG was performed in the chronic stage of myocardial infarction or the stable phase of angina pectoris, but three patients underwent repeated CAG studies during the acute phase of myocardial infarction. The percent diameter of the narrowing in the lesion was assessed according to the AHA system. Concerning the sites of lesions with progression to complete occlusion, 14 (56%) were located in the proximal segment of the left anterior descending artery (segment 6 or 7), and six lesions were in the main trunk of the right coronary artery (segment 1, 2 or 3). In 11 patients with stable angina, associated lesions showed progression from 90 or 99% stenosis to complete occlusion. Seven patients with lesions exhibiting 99% stenosis had collaterals, and four patients with lesions exhibiting 90% stenosis had no collaterals during the first study. However, good collaterals were demonstrated in all patients in the second study. Seven patients had episodes of newly developed unstable angina. The lesions in five of the seven patients progressed from 75% or 90% stenosis to complete occlusion, and in one patient with triple vessel disease the lesion progressed from 99% stenosis to complete occlusion in the second study. The former five patients did not have collaterals in the first study, but development of collaterals was demonstrated in all seven patients in the second study. Seven patients had episodes of myocardial infarction, and in six of these, the lesions progressed from 75% or less stenosis to complete occlusion.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1988

Echocardiographic findings in nine patients with cardiac amyloidosis: their correlation with necropsy findings.

The echocardiographic abnormalities of nine patients with cardiac amyloidosis were correlated with their postmortem findings. All had congestive heart failure and autopsy-proven amyloidosis. M-mode echocardiographic features included (1) small or normal left ventricular (LV) dimensions; (2) thickened interventricular septa and posterior LV walls (89%); (3) left atrial enlargement (89%); and (4) reduced LV distensibility (78%, 100%) and contractility (22%, 44%). Serial M-mode echocardiography revealed that cardiac amyloidosis was initially manifested as diastolic LV dysfunction rather than systolic dysfunction. The final stage of this disease was characterized by severe impairment of both systolic and diastolic LV functions. Two-dimensional echocardiography provided additional features: (1) a more accurate diagnosis of pericardial effusion (67%) and (2) a characteristic "granular sparkling" appearance of the ventricular wall (55%). In four of five cases, these hyperrefractile myocardial echoes corresponded to scattered amyloid deposits histopathologically. There was no correlation between the types of amyloid deposits and the hyperrefractile myocardial echoes. Thus, cardiac involvement in systemic amyloidosis could be non-invasively assessed by M-mode and two-dimensional echocardiography.

Adult↗