Biomedical subjects

Y Terada

Publications and source records attributed to Y Terada.

At least 235 records · Page 13Linked to original sources

PubMed1994

PCR localization of C-type natriuretic peptide and B-type receptor mRNAs in rat nephron segments.

The present study was undertaken to investigate the presence of C-type natriuretic peptide (CNP) mRNA and its receptor, natriuretic peptide B-type receptor (ANPR-B) mRNA, in rat renal structures. The microlocalization of mRNAs coding for CNP and ANPR-B was carried out in the rat kidney, using an assay of reverse transcription and polymerase chain reaction (RT-PCR) in individual microdissected renal tubule segments, glomeruli, vasa recta bundle, and arcuate arteries. The PCR signal for CNP was detected in glomerulus, vasa recta bundle, and arcuate artery. The PCR product of ANPR-B was widely present in renal structures. Relatively large amounts of ANPR-B PCR product were detected in glomerulus, vasa recta bundle, arcuate artery, and distal nephron segments. A relatively high concentration of CNP (10(-7) M) stimulated guanosine 3',5'-cyclic monophosphate accumulation in glomerulus, medullary thick ascending limb, cortical collecting duct, and inner medullary collecting duct. Our data demonstrate that CNP can be produced locally in the glomerulus and renal vascular system and that ANPR-B is widely distributed in renal structures. Thus CNP may influence renal function and act in autocrine and paracrine fashions in the kidney.

Animals↗

PubMed1994

Distribution of kallikrein-binding protein mRNA in kidneys and difference between SHR and WKY rats.

We investigated kallikrein-binding protein (KBP) mRNA distribution in the kidney of Sprague-Dawley (SD) rats, spontaneously hypertensive rats (SHR), and Wistar-Kyoto strain (WKY) rats. Northern blot analysis revealed that KBP mRNA was located mainly in the medulla and with lower amounts in SHR than in WKY rats. KBP mRNA in microdissected nephron segments was detected by reverse transcription and polymerase chain reaction (RT-PCR) followed by Southern blot analysis. In SD rats, the most abundant signals were consistently found in inner medullary collecting duct (IMCD), with small amounts in outer medullary collecting duct, proximal convoluted tubule, and glomerulus. No signals were found in connecting tubule and cortical collecting duct. The nephron distribution of KBP mRNA was similar in WKY and SD rats. Only a small amount of signal was found, however, in IMCD of SHR. In conclusion, 1) KBP mRNA was predominantly distributed in the medullary segments of the distal nephron, downstream from the known kallikrein activity site in the collecting duct, and 2) KBP mRNA expression was significantly decreased in the kidney of SHR.

Animals↗

PubMed1994

Neurons with high-frequency discharge in the central nervous system in chronic pain.

Prior to implantation of the thalamic- or motor cortex-stimulating electrodes for relieving chronic pain, extracellular unitary activity was recorded and local microstimulation was done, by using microelectrodes, mainly in the ventral caudal nucleus of the thalamus. A significant number of high frequency discharge neurons (hyperactive neurons) were recorded and showed three types of discharge patterns with different interval histograms. In animal experiments, unilateral dorsal root sectioning from C5 to Th1 of male Wistar rats was made according to the method of Lombard et al[4]. One to three months after the operation, cellular activity was recorded from the contralateral thalamic nuclei (VP, zona incerta), lemniscus medialis and striatum. Hyperactive neurons were recorded from the thalamic nuclei and lemniscus medialis. The firing patterns and distribution of hyperactive neurons in these animals were very similar to those of humans. Hyperactive neurons were examined via electrical stimulation of and/or iontophoretical application of chemical substances. Hyperactive neurons were unaffected by electrical stimulation of the nucleus raphe dorsalis and locus ceruleus. However, sensorimotor cortical stimulation showed a reduction of firing in the hyperactive neurons. Iontophoretic application of glutamate showed increase in firing and GABA showed remarkable firing suppression. These results suggested that hyperactive neurons of the thalamic nuclei receive a facilitatory effect from the sensorimotor cortex with little influence from adrenergic or serotonergic systems, and these neurons have a relationship to the glutamatergic and GABAergic fibers or receptors.

Action Potentials↗

PubMed1994

Thimerosal induces toxic reaction in non-sensitized animals.

The effects of injection of thimerosal solution on nonsensitized animals was investigated. Intrafootpad injection of thimerosal solution in nonsensitized mice resulted in a swelling response which peaked 1 h after injection and lasted for more than 24 h. Histopathological examination showed that there were severe edema and infiltration of polymorphonuclear neutrophils at the site of injection. An increased vascular permeability was observed after cutaneous injection of thimerosal solution on the back of nonsensitized rats. Since mercuric chloride and methyl mercury induced severer reactions, and thiosalicylic acid had no effect, mercury contained in thimerosal would have caused the reactions observed in this study. These results suggest that part of these hypersensitivity reactions against thimerosal observed among patients were possibly induced by the toxic effect of thimerosal. Therefore, thimerosal contained as a preservative in vaccine may augment the side-effects of the vaccination.

Animals↗

PubMed1994

Endothelin (ET)-3 stimulates cyclic guanosine 3',5'-monophosphate production via ETB receptor by producing nitric oxide in isolated rat glomerulus, and in cultured rat mesangial cells.

We investigated the effects of endothelins on receptor-mediated cyclic nucleotide metabolism in rat glomerulus, inner medullary collecting duct (IMCD), and also in cultured rat glomerular mesangial cells. Endothelin (ET)-3 dose-dependently stimulated cGMP accumulation in glomerulus, which was higher than that of ET-1 or ET-2. ETB receptor agonist IRL 1620 produced cGMP in a dose-dependent manner, mimicking the effect of ET-3. ETA receptor antagonist BQ123-Na did not inhibit ET-3- or IRL 1620-stimulated cGMP generation. NG-monomethyl-L-arginine (L-NMMA) significantly inhibited ET-3- or IRL 1620-induced cGMP production, suggesting that ET-3- or IRL 1620-stimulated cGMP generation was mediated through nitric oxide (NO). Intracellular Ca chelator BAPTA/AM and calmodulin antagonist W-7, but not Ca channel blocker nicardipine, significantly inhibited ET-3- or IRL 1620-induced cGMP generation. In cultured rat mesangial cells, ET-3 stimulated cGMP generation through NO in the presence of fetal calf serum, which was not inhibited by addition of BQ123-Na. In IMCD, ET-3 had no stimulative effect on cGMP generation. We conclude that ET-3 stimulates NO-induced cGMP generation through ETB receptor in glomerulus. This effect seems to be mediated through intracellular Ca/calmodulin, but not through Ca influx via L-type Ca channel. Mesangial cells can be a source of NO coupled to ETB receptor activation in glomerulus. From these results, mesangial ETB receptor may work to counteract the vasoconstrictive effect of endothelin caused via ETA receptor in glomerulus.

1-Methyl-3-isobutylxanthine↗

PubMed1994

Superior vena cava syndrome caused by a right apical tense bulla.

Superior vena cava (SVC) syndrome is caused by several diseases, although to our knowledge, a bullous lesion has not been reported previously. In the present case, severe pleural adhesion prevented the expanding bulla from stretching the visceral pleura and from compressing the residual lung, subsequently causing compression of the SVC and thus SVC syndrome.

Female↗

PubMed1994

An autopsy case of pyruvate kinase deficiency anemia associated with severe hemochromatosis.

We report an autopsy case of pyruvate kinase deficiency anemia with severe hemochromatosis. This anemia is rarely associated with hemochromatosis. In this case, the autopsy findings showed hemochromatosis of the heart, pancreas, liver, kidneys, thyroid gland, adrenal glands, testes and skin. Microscopic examination showed iron depositions in these organs, but not in the bone marrow. A family study showed negative data for iron overload and no known HLA type suggestive of idiopathic hemochromatosis. To explain this rare association, we suggest that this patient's iron overload was an acquired type, which might have mainly been caused by increased iron absorption due to the severe hemolytic anemia.

Adult↗

PubMed1994

[Thrombolytic therapy of thrombosed Björk-Shiley aortic valve prosthesis--report of four cases].

Prosthetic valve thrombosis is associated with high mortality. Thrombolytic therapy is a promising alternative to valve replacement in the management of prosthetic valve thrombosis. To determine the efficacy and safety of thrombolytic therapy for thrombosed Björk-Shiley aortic valve prosthesis, 4 patients who received urokinase intravenously for this disorder were analyzed. In 3 patients, the successful outcome was sustained in that they remained asymptomatic and did not require operative intervention during follow-up, which ranged from 17 to 101 months. In one patient clinical signs of mild congestive heart failure occurred. This patient was surgically treated by thrombectomy and debridement of the prosthetic valve. Failure of urokinase treatment to resolve the thrombus after 1 week indicates that tissue overgrowth or fibrous, organized thrombus is the cause of prosthetic malfunction. Surgical intervention for this problem should be considered only after thrombolytic therapy has been tried and has failed. Our experience with urokinase treatment of thrombosis of aortic Björk-shiley prostheses indicates that this form of treatment should always be applied before surgical intervention. We also attempted to define the optimum protocol of fibrinolytic therapy by clinical evaluation. A protocol for the safe treatment of thrombosed valve is urokinase in initially administered in the doses as 960,000 units for 24 hours, then followed by a maintenance infusion at the half dose every 24 or 48 hours later. Thrombolytic therapy should be continued for 1 week at least to prevent rethrombosis even normalization of valve function was documented clinically. Simultaneous heparin infusion of 10,000 units for 24 hours is then started to replaced by warfarin treatment adjusted to obtain optimal prothrombin times.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

[Early repair of postinfarction ventricular septal perforation: a case report of an improved surgical technique].

Accurate repair of postinfarction ventricular septal perforation (VSP) has mainly depended on the technique for friable septal reinforcement. Modified closure of VSP with Xenomedica patch was performed in 63-year-old male. Friable border of the septum was successfully sandwiched between horse-shoe shape prejett (right side) and main patch (left side). The advantages of this modified surgical procedure are as follows: (1) septum can be seen through horse-shoe shape patch (even when tying the mattress sutures; (2) Xenomedica patch is flexible enough for avoiding the cutting for friable septum, and is strong enough for sandwiching the septum.

Heart Rupture, Post-Infarction↗

PubMed1994

[A case of coronary artery bypass grafting (CABG) in which root mean square total (RMST) improved markedly after redo-distal anastomosis].

A 59-year-old man underwent CABG with left internal thoracic artery (LITA) to the first diagonal branch and saphenous vein graft (SVG) to the right coronary artery (RCA). Pump off was quite uneventful, but re-anastomosis was done because bypass graft flow measured before the closure of chest was 6 ml/min, which was most likely due to sclerotic right coronary artery and technical error. After re-anastomosis, bypass flow of SVG to RCA was measured 95 ml/min. Root mean square total (RMST) immediately after aortic declamp for the first time was 39% compared with that measured prior to operation, but improved to 49% after aortic declamp at the second time. It recovered to 127% 2 days after operation, and 137% at 7th postoperative day. RMST indicates the total electropotential per unit time from the beginning to the end of QRS. It has the specificity to predict VT and postoperative pump failure. In this case, it is suspected that RMST may be a predictor that revascularization would be complete or incomplete in operations for ischemic heart disease.

Anastomosis, Surgical↗

PubMed1994

[Influence of ionized calcium concentration during cardiopulmonary bypass on pediatric cardiac surgery].

Changes of serum ionized calcium concentration (Ca2+) during cardiopulmonary bypass (CPB) were analyzed in 30 pediatric cardiac patients less than 15 kg body weight. Ca2+ decreased suddenly after the start of CPB, and it gradually increased to the normal value. Citrate added to the stored blood for priming and its metabolism might play a role in these changes of Ca2+. Addition of adequate volume of calcium chloride to the priming prevented sudden decrease of Ca2+. Although addition of citrate before aortic declamp effectively decreased Ca2+ and may prevent reperfusion cardiac injury associated with hypercalcemia, there were no correlation between predeclamp level of Ca2+ and serum CPK and GOT levels.

Body Weight↗

PubMed1994

[Two cases of coronary artery bypass grafting using great saphenous vein grafts in reversed Y-shaped for the atherosclerotic ascending aorta].

Coronary artery bypass grafting (CABG) was performed using saphenous vein grafts anastomosed in reversed Y-shaped in two patients because of the atherosclerotic ascending aorta. Postoperative course was uneventful, however, the common part of reversed Y-shaped grafts was occluded in both patients within two years after operations. The arms of reversed Y-shaped grafts were patent, and played a role of major collateral between LAD and RCA. They were treated successfully with reoperation in one patient and PTCA in another.

Aged↗

PubMed1994

[A case of atelectasis of the middle lobe associated with congestive heart failure].

A 74-year-old man was admitted to our hospital for work up of a shadow in the right middle lobe on chest X-ray film. He had hypertension, aortic regurgitation, and atrial fibrillation on admission. Bronchoscopy demonstrated total obstruction of the right B4 orifice, but the etiology of obstruction was unknown. He was discharged and followed up. The shadow in the middle lobe disappeared spontaneously and the cardiac silhouette was slightly smaller than that on the first admission. The shadow in the middle lobe reappeared again with the progression of cardiomegaly. Because hypertension became uncontrolled and pretibial edema developed, he was readmitted. Bronchoscopy showed the same findings as on the first admission. After treatment of heart failure for one month, bronchoscopy demonstrated partial patency of the right B4 orifice. As cardiomegaly improved, the shadow in the middle lobe diminished and then disappeared, and chest CT scan showed patency of the right B4. These findings suggest that congestive heart failure caused the atelectasis of the right middle lobe, so-called middle lobe syndrome. A possible mechanism of the right B4 obstruction is that the right B4 was compressed between the middle lobe artery and the dilated middle lobe vein due to heart failure.

Aged↗

PubMed1994

[A case of Cabrol's procedure in which selective cerebral perfusion was necessitated].

A 69-year-old man underwent Cabrol's procedure for annuloaortic ectasia and complicated multiple cerebral infarction. Preoperative CT scan showed atherosclerotic changes from the aortic arch to descending aorta. During extracorporeal circulation, arterial cannulation was made through left subclavian artery to prevent cerebral infarction due to detouched atheroma from the descending aorta. Intraoperatively, the ascending aorta was also atheromatous and ulcerative. In this case, cerebral infarction was most likely due to detouched atheroma from the aortic arch in retrograde blood flow during extracorporeal circulation. To prevent this complication, selective cerebral perfusion during extracorporeal circulation should have been selected.

Aged↗

PubMed1994

[Late cardiac tamponade after open heart surgery].

59 cases of late cardiac tamponade following open heart surgery were studied. The incidence was 2.1%. Postoperative prolonged heart failure, anticoagulants, and blood in the pericardium left undrained may play a role in its pathogenesis. Echocardiography was the sure method of diagnosis. Insertion of a drainage tube into the pericardium through the subxiphoid approach was effective with minimal invasion and a treatment of choice.

Adolescent↗

PubMed1994

[Simultaneous operations for ischemic heart disease and lung cancer].

Two cases were operated on simultaneously for coronary revascularization and lung resections for cancer. Case 1 was a 79 year-old man, diagnosed with two vessels coronary artery disease and squamous cell carcinoma of left lower lobe. At the end of aortocoronary bypass grafting to LAD and first diagonal branch using saphenous vein, median sternotomy was closed, and lower lobectomy was performed through left posterolateral standard thoracotomy. Case 2 was a 65 year-old man who underwent aortocoronary bypass grafting to LAD first and left lingular segmentectomy via median sternotomy simultaneously. We concluded that a simultaneous operation was definitively and ideally a preferable method in most selected cases. The order of two operations for coronary artery and lung was also discussed.

Aged↗

PubMed1994

[Present status of IVOX device].

IVOX was named as an acronym for intravascular oxygenator. The device does not need a blood pomp like an extracorporeal membrane oxygenator (ECMO), and performs intracorporeal gas exchange to be a small elongated, hollow fiber membrane oxygenator designed to lie within the subject's venae cavae so that circulating venous blood can flow freely over and around the external surfaces of the hollow fibers. The amount of gas exchange in IVOX is less than ECMO, however, the equipment is simple and there is no effect to hemodynamics and body temperature. IVOX has been utilized in the management of 165 clinical trials patients in 31 international critical care centers. Currently the gas transfer rate by means of the IVOX device constitutes 1/4 to 1/3 the total metabolic requirement of adult acute respiratory failure patients. Therefore, intentional hypoventilation to limit airway pressures (mild permissive hypercapnia) is recommended to improve CO2 removal with increasing mixed venous CO2 concentrations. In the future, improvements of design, function, and methods of utilization of IVOX device are expected to increase the amount of gas exchange and to enlarge the indications for its use.

Humans↗

PubMed1993

C fiber generates a slow Na+ spike in the frog sciatic nerve.

The present study was carried out to examine the properties of A and C fibers in the bullfrog sciatic nerves by applying several agents through perfusing solutions between stimulating and recording electrodes. The compound action potentials (CAPs) of A beta and A delta fibers were tetrodotoxin (TTX)-sensitive and were abolished in Na(+)-free solution. However, C fiber CAP was TTX-insensitive although CAP disappeared in Na(+)-free solution. Moreover, C fiber CAP was not blocked by Ca2+ channel blockers and its chronaxy (2 ms) and conduction velocity (0.70 m/s) indicate that the time constant of C fiber CAP is relatively large (2.88 ms). These suggest that a slow Na+ channel, which is TTX-resistant, contributes to C fiber action potentials.

Action Potentials↗