Optical reflectivity spectra of single-crystal Bi2Sr2Can-1CunO2n+4+x (n=1 and 2).
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Journal Article↗
Biomedical subjects
S Uchida
Publications and source records attributed to S Uchida.
Reactive hyperaemic flow characteristics of the right coronary artery compared to the left anterior descending coronary artery in the open-chest dog.
Reactive hyperaemia, the cardiovascular response to transient occlusion of a vessel, was examined and compared in the right coronary artery (RCA) and the left anterior descending coronary artery (LAD) in the same heart of an open-chest dog. First, to study the relationship between reactive hyperaemia and occlusion time in the RCA and LAD, respective flows were measured and reactive hyperaemia was induced with different occlusion times. Occlusion time required for half the maximum peak percentage reactive hyperaemic flow (%PRH), t 1/2, for the RCA was approximately twice that of the LAD: 11.4 +/- 2.3 s versus 5.9 +/- 1.4 s. Maximum %PRH of the RCA was significantly greater than that of the LAD while the percentage repayment of the RCA was lower than that of the LAD. Augmentation of right ventricular oxygen consumption shortened t 1/2 and increased percentage repayment significantly. Second, to determine "critical pressure", which was defined as the perfusion pressure below which reactive hyperaemia was abolished completely, the RCA and LAD were perfused through a shunt from the carotid artery, perfusion pressure was varied in the range of 100 to 20 mmHg and reactive hyperaemia was induced. Critical pressure in the RCA was significantly lower than in the LAD: 32.2 +/- 5.7 mmHg versus 41.5 +/- 5.0 mmHg. These results suggest that the RCA has a greater flow reserve than the LAD. These results were consistent with the difference of oxygen metabolism between the right and left ventricles. The difference of oxygen metabolism between the two ventricles would, at least partly, account for these results.
Animals↗
Effect of denervation of the phrenic nerve on the action of calcitonin gene-related peptide in rat diaphragm.
The effect of denervation on Calcitonin gene-related peptide (CGRP)-induced enhancement of the twitch contraction of skeletal muscle was studied. In rat diaphragm denervated 2 weeks previously, the basal twitch contraction induced by transmural stimulation was about twice that in control muscle, and the basal adenylate cyclase activity and cyclic AMP (cAMP) contents of the tissue were increased. This denervation did not affect the dose-dependent beta -adrenergic stimulation of twitch contraction, but abolished the CGRP-induced enhancement of twitch contraction. The latter phenomenon seems to be caused in part by decrease in CGRP-induced accumulation of cAMP over the basal level, because of increase in the basal cAMP level after denervation. The involvement of another inhibitory second messenger system coupled with CGRP receptors is discussed.
Adenylyl Cyclases↗
Profiles of [3H]N-[1-(2-thienyl)cyclohexyl]piperidine binding in brain synaptic membranes treated with Triton X-100.
Binding of [3H]N-[1-(2-thienyl)cyclohexyl]piperidine (TCP) was examined using rat brain synaptic membranes treated with a low concentration of Triton X-100. This compound is assumed to be a non-competitive antagonist for the N-methyl-D-aspartate(NMDA)-sensitive subclass of central excitatory amino acid receptors. Binding was quite low but detectable in Triton-treated membranes irrespective of the incubation temperature, and the temperature-dependent portion of the binding was greatly reduced in these Triton-treated membranes. However, binding was drastically potentiated by the inclusion of L-glutamate and its analogous amino acids in a concentration-dependent manner at a concentration range of 10 nM to 0.1 mM. Agonists for the NMDA-sensitive subclass also potentiated binding, with agonists for the other subclasses being ineffective. Glycine at a concentration above 10 nM was not only effective as a stimulant of potentiated binding by glutamate, but was also active in enhancing binding in the absence of added glutamate. Glycine increased both the association and dissociation rates without significantly affecting the dissociation constant. Pharmacological profiles of binding in Triton-treated membranes were not significantly different from those in untreated membranes, except for that of haloperidol. Haloperidol is proposed to be highly selective for brain sigma-receptors on the basis of a potent inhibition of sigma-receptor binding. The inhibitory potency of this sigma-ligand was markedly attenuated in the presence of both glutamate and glycine in Triton-treated membranes, as compared with that in untreated membranes. These results suggest that [3H]TCP binding in Triton-treated membranes is a useful biochemical tool to evaluate predominantly the activated state of ion channels associated with the NMDA-sensitive receptors in terms of freedom from the confounding effects of endogenous amino acids.
Animals↗
Release of calcitonin gene-related peptide-like immunoreactive substance from neuromuscular junction by nerve excitation and its action on striated muscle.
In a rat phrenic nerve-hemidiaphragm preparation, calcitonin gene-related peptide (CGRP) increased the twitch contraction induced by nerve or transmural stimulation dose dependently. Either electrical or high K+ stimulation of the phrenic nerve caused release of a CGRP-like immunoreactive substance (CGRP-LIS) in a Ca2(+)-dependent manner. Electrical stimulation of the phrenic nerve also increased the cyclic AMP content in diaphragm. This increase was not observed in Ca2(+)-free medium and was blocked by antiserum against CGRP. These results indicate that excitation of the motor nerve causes release of CGRP-LIS at nerve terminals and that the released CGRP-LIS increases the cyclic AMP content of skeletal muscles and potentiates twitch contraction.
Animals↗
Premature chromosome condensation is induced by a point mutation in the hamster RCC1 gene.
At the nonpermissive temperature, premature chromosome condensation (PCC) occurs in tsBN2 cells derived from the BHK cell line, which can be converted to the Ts+ phenotype by the human RCC1 gene. To prove that the RCC1 gene is the mutant gene in tsBN2 cells, which have RCC1 mRNA and protein of the same sizes as those of BHK cells, RCC1 cDNAs were isolated from BHK and tsBN2 cells and sequenced to search for mutations. The hamster (BHK) RCC1 cDNA encodes a protein of 421 amino acids homologous to the human RCC1 protein. In a comparison of the base sequences of BHK and BN2 RCC1 cDNAs, a single base change, cytosine to thymine (serine to phenylalanine), was found in the 256th codon of BN2 RCC1 cDNA. The same transition was verified in the RCC1 genomic DNA by the polymerase chain reaction method. BHK RCC1 cDNA, but not tsBN2 RCC1 cDNA, complemented the tsBN2 mutation, although both have the same amino acid sequence except for one amino acid at the 256th codon. This amino acid change, serine to phenylalanine, was estimated to cause a profound structural change in the RCC1 protein.
Amino Acid Sequence↗
Effects of interferon gamma on cultured synovial cells from patients with rheumatoid arthritis: inhibition of cell growth, prostaglandin E2, and collagenase release.
The effects of recombinant interferon gamma (rIFN gamma) on the in vitro growth of adherent synovial fibroblast-like cells from patients with rheumatoid arthritis (RA) and also on the release of prostaglandin E2 and collagenase from these cells stimulated with recombinant interleukin-1 beta (rIL-1 beta) were investigated. The growth of adherent synovial cells from six of nine samples, determined by [3H]thymidine incorporation, was inhibited by rIFN gamma in a manner dependent on dose. The release of prostaglandin E2 and collagenase from adherent synovial cells stimulated with rIL-1 beta was also suppressed by rIFN gamma in all samples tested, though the basal release of these inflammatory mediators was little influenced. No apparent correlation between inhibition of proliferation by rIFN gamma and either inhibition by rIFN gamma of rIL-1 beta stimulated prostaglandin E2 release or the endogenous synthesis of prostaglandins was found.
Arthritis, Rheumatoid↗
Direct effects of endothelin in the rat kidney.
In the present study, we tested the direct effects of endothelin (ET) on rat kidney in vivo. ET was infused into the left renal artery of anesthetized rats at a rate of 0.5, 5, 20, or 40 pmol/h. ET reduced ipsilateral urine volume (V), clearance of inulin (CIN), and clearance of p-aminohippuric acid (CPAH) in a dose-dependent manner. Thus ET at 20 pmol/h did not change V but decreased renal plasma flow (RPF) and glomerular filtration rate (GFR) by 27.6 +/- 14.3 and 30.8 +/- 10.4%, respectively, in the ipsilateral kidney. ET at 0.5 pmol/h was without effect and at 5 pmol/h had only minor effects on CIN and CPAH of ipsilateral kidney. At 40 pmol/h, ET reduced ipsilateral V, GFR, and RPF by 52.3 +/- 21.4, 58.4 +/- 14.5, and 72.5 +/- 10.6%, respectively. Filtration fraction and fractional excretion of Na remained unchanged during ET infusion. ET, 40 pmol/h, infused into the renal artery together with atrial natriuretic peptide (ANP) at a rate of 12 pmol/h reduced the ipsilateral V, GFR, and RPF by 33.2 +/- 6.3, 26.1 +/- 6.0, and 27.2 +/- 7.1%, respectively, decrements less than those with ET alone. When a calcium-channel blocker nicardipine was infused at a rate of 2.5 micrograms/h into the renal artery together with ET, 20 pmol/h, there was little change in the ipsilateral V, RPF, and GFR; ET, 40 pmol/h, with nicardipine did not change V and decreased GFR and RPF by 25.9 +/- 5.6 and 23.1 +/- 10.8%, respectively, decrements less than those without nicardipine.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Unilateral renal agenesis associated with various metabolic disorders in three siblings.
Unilateral renal agenesis with impaired renal function was found in all 3 siblings of a single family, in association with various metabolic disorders such as diabetes mellitus, hyperuricemia and hyperbilirubinemia with gallstones. The present report suggests that unilateral renal agenesis could occur as a manifestation of a genetic disorder.
Adult↗
Adult Fanconi syndrome secondary to kappa-light chain myeloma: improvement of tubular functions after treatment for myeloma.
A 66-year-old man with kappa-light chain multiple myeloma had adult Fanconi syndrome. Renal tubular transport abnormalities consisted of renal tubular acidosis, renal glycosuria, aminoaciduria, phosphaturia and renal hypouricemia. After therapy for multiple myeloma, urinary Bence Jones protein became undetectable, and all these renal tubular abnormalities except urate wasting were corrected. Histological examination revealed electron-dense tubular and rod-like deposits in proximal tubular epithelium. This clinical observation suggests that the renal tubular transport defects were secondary to the myeloma process, possibly due to Bence Jones proteinuria.
Aged↗
Systemic effects of carteolol, a beta-adrenoceptor antagonist in stroke-prone spontaneously hypertensive rats.
The preventive effects of carteolol, a beta-adrenoceptor antagonist, on secondary lesions were pathophysiologically examined in stroke-prone spontaneously hypertensive rats (SHRSP) from 8 to 30 weeks of age. Carteolol was added to the drinking water in doses of 0.005% (8 to 18 weeks of age) to 0.01% (19 to 30 weeks of age) (3.8 and 6.0 mg/kg/d, respectively). These animals gained significantly more weight than the untreated control SHRSP, and their heart rate reduced from 14 weeks of age. Suppression of blood pressure rise was not definite, however, histology revealed prevention of the development or aggravation of secondary hypertension-related lesions, such as myocardial fibrosis, proliferative arteriolitis, necrotic arteriolitis and renal glomerular lesions. A decrease in non-esterified fatty acids in the serum was evident. Thus, carteolol has cardiac as well as renal protective effects, in the SHRSP.
Adrenal Glands↗
Prolongation of life span of stroke-prone spontaneously hypertensive rats (SHRSP) ingesting persimmon tannin.
The effects of persimmon tannin on pathophysiological changes in stroke-prone spontaneously hypertensive rats (SHRSP) were investigated. When the persimmon tannin was chronically ingested by SHRSP, the life span was significantly prolonged, yet the effect on blood pressure was slight. The incidences of brain hemorrhage and infarction were also significantly decreased by this treatment. To elucidate the mechanisms involved in these events, the effects of condensed tannins, including persimmon tannin, on free radicals and lipid peroxidation were examined in vitro. Using electron spin resonance analysis, we found that these tannins have a potent, concentration-dependent scavenging action toward active oxygen free radicals. These tannins strongly inhibited lipid peroxidation in rat brain homogenates, in a concentration-dependent manner. Persimmon tannin inhibited lipid peroxidation similarly to (-)-epigallocatechin. Persimmon tannin was 20 times more effective than alpha-tocopherol in terms of the 50%-inhibitory concentration. The radical scavenging action and inhibition of lipid peroxidation by persimmon tannin may explain, in part, the prolongation of the life span of the SHRSP ingesting persimmon tannin.
Animals↗
[Progress in the study of muscarinic acetylcholine receptors; establishment of the subtypes or subgroups].
Since acetylcholine (ACh) was identified as a neurotransmitter at parasympathetic nerve terminals by pioneering pharmacologists such as O. Schmiedeberg, R. Hunt, O. Loewi and H.H. Dale, muscarinic acetylcholine receptors (mACh-R) serving as a transducer of muscarinic action have been assumed to exist. After many tries to identify the mACh-R, it's existence was established by the group of S.H. Snyder, who employed binding assays with the radioligand 3H-QNB. The presence of a neuronal (M1) and a peripheral (M2) mACh-R was suggested from the action of an M1-specific agonist, McN-A-343; and this observation was followed by the discovery that the antagonist pirenzepine had higher affinity for M1 than for M2. Later, peripheral mACh-Rs were further subclassified in two types by the heart-specific action of gallamine and the different affinities of AF-DX116 and 4-DAMP. At present, three subtypes, M1 (neuronal), M2 (heart) and M3 (other peripheral organs), can be pharmacologically distinguished by affinity differences. On the other hand, purification of mACh-R and analysis by gene technology revealed the presence of five mACh-R mRNAs (m1-m5), which were expressed in various organs with different abundances. These subtypes couple with subcellular muscarinic responses through different GTP-binding proteins. The connection between the subtypes, GTP-binding proteins and responses is not fully understood yet. Our studies showed that in guinea pig heart, in which only m2 mRNA is expressed, muscarinic agonists recognize two subgroups (M2 alpha and M2 beta) with different affinities. One couples with the inhibition of adenylate cyclase, and the other couples with PI turnover through different GTP-binding proteins.(ABSTRACT TRUNCATED AT 250 WORDS)
Binding Sites↗
[Antihypertensive effects of betaxolol, a cardioselective beta-adrenoceptor antagonist, in stroke-prone spontaneously hypertensive rats (SHRSP)].
Effects of betaxolol, a cardioselective beta-adrenoceptor antagonist, on blood pressure and hypertensive complications in stroke-prone spontaneously hypertensive rats (SHRSP) were investigated. Betaxolol was provided in a dose of 33 +/- 1.8 mg/kg/day, orally in drinking water, throughout the experimental period. The chronic treatment with betaxolol inhibited the development of hypertension in SHRSP and reduced values of blood urea nitrogen, creatinine, total cholesterol, free cholesterol, triglyceride, phospholipid and HDL-cholesterol in serum. Treatment with betaxolol apparently inhibited the incidence of hypertensive lesions such as cardiac fibrosis, mesenteric vasculitis, proliferative and/or necrotic vasculitis and glomeruli showing collapse or vasculitis in the kidneys. To shorten the time before the onset of hypertension and the subsequent stroke, SHRSP were kept on a SP diet containing 0.39% Na instead of the F-2 diet. When the SHRSP were kept on the SP diet, all of the control SHRSP had cerebral apoplexy and severe hypertensive lesions in the heart and kidney. When betaxolol was chronically administered to SHRSP, cerebral apoplexy and hypertensive lesions in the heart and kidney were inhibited, but the effect on blood pressure was slight. Treatment with betaxolol reduced serum creatinine levels. Our observations show that betaxolol reduces blood pressure and potently inhibits hypertensive complications in SHRSP.
Adrenergic beta-Agonists↗
Effect of membrane depolarization by high K+ on carbachol-stimulated phosphoinositides hydrolysis in guinea pig cerebral cortical slices.
Stimulation of phosphoinositide hydrolysis by carbachol was studied in slices of guinea pig cerebral cortex under normal conditions (4.7 mM K+) and depolarization conditions with high K+ (42 mM K+). Slices were labeled with [myo-3H]-inositol, and the effects of carbachol and high K+ on the formation of inositol-bisphosphates (IP2) and inositol-trisphosphates (IP3) were determined. Carbachol (10 mM) caused only 140% stimulation of the formations of IP2 and IP3 over the control value in normal Krebs Ringer Buffer (KRB), but about 200% stimulation in high K+ medium. Dose-response curves for the effect of carbachol on the formations of IP2 and IP3 showed that high K+ medium selectively decreased the ED50 value of carbachol for IP2 formation about 3-fold. A Ca++ channel blocker, verapamil, inhibited the synergistic effect of carbachol and high K+ on IP2 formation, and a decrease in extracellular Ca++ also inhibited IP2 formation induced by high K+, but these treatments had little, if any, effect on IP3 formation. The possibility that IP2 may be directly generated by hydrolysis of phosphatidylinositol 4-monophosphate (PIP) as well as from hydrolysis of IP3 was discussed.
Animals↗
[Electromyographic studies on the exhibition of isometric protrusive and lateral protrusive mandibular forces].
To study the mechanism of exertion of horizontal mandibular force, the myoelectric effect of mandibular isometric protrusive and lateral protrusive contraction under four forces (1/4, 2/4, 3/4, or 4/4 of the maximum voluntary contraction) at three different jaw positions (O: centric occlusion, half: middle position between O and max, and max: maximum eccentric protrusive or lateral protrusive mandibular positions) was measured in six male subjects with normal jaw function. Electromyographic recordings of the inferior part of the lateral pterygoid (LPt), posterior temporalis (Tp) and masseter (Mm) muscles were taken bilaterally, and forces were measured with force transducer. EMG activities in the bilateral LPt during isometric protrusive contraction and in the contralateral LPt during lateral protrusive contraction increased with load intensity. Mm bilaterally during protrusive contraction, ipsilateral Tp and contralateral Mm during lateral protrusive contraction played an auxiliary role in exertion of horizontal mandibular force. EMG activities in the contralateral LPt during lateral protrusive contraction with every force and in the bilateral LPt during protrusive contraction with 1/4, 2/4, 3/4 force, were significantly increased under the eccentric mandibular position. However, EMG activities in the bilateral LPt during protrusive contraction with 4/4 force did not increase under the eccentric mandibular position. EMG activity in the LPt during protrusive contraction were higher than that during lateral protrusive contraction at every mandibular position and with every force. It was concluded that the LPt was predominantly concerned with exertion of horizontal mandibular force.
Electromyography↗
Colonic anisakiasis simulating carcinoma of the colon.
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Colonic Diseases↗
[Well controlled comparative study in early rheumatoid arthritis with gold sodium thiomalate vs. auranofin].
RA Center Liaison Council conducted a comparative study of Auranofin and GST by envelope method on the patients with early RA who experienced the onset of the disease not more than two years ago. In final assessment of overall improvement, 57.9% of Auranofin-administered cases (22/38) showed moderate improvement or above. The comparable figure for GST group was 71.8% (28/39), but there was no statistically significant difference. Adverse reaction ADR incidence for Auranofin group was 12.2% (5/41), while 22.0% for GST (9/41), but the difference was not statistically significant. Drop out due to ADR was observed in 9.8% of Auranofin-administered cases and in 19.5% of GST-administered cases. The results of the study indicate that Auranofin is a most suitable DMARD than GST to be used for early RA, and GST is suitable for more active RA in view of its efficacy. But GST should be administered carefully because of its high ADR incidence.
Adolescent↗