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Biomedical subjects

S Tsukamoto

Publications and source records attributed to S Tsukamoto.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Effectiveness of low dose continuous infusion of alpha-hANP from the start of cardiopulmonary bypass].

In this study, we used alpha-human atrial natriuretic peptide (hANP) from staring on cardiopulmonary bypass and evaluated for the hemodynamics, ANP, renin activity, aldosterone, urine volume, glomerular filtration rate (GFR) and so on. The hANP decreased renin activity, aldosterone, systemic vascular resistance and increased urine volume, GFR and use of furosemide and KCL were decreased. We concluded that hANP was effective for hemodynamics, renal function and hormonal release on intra and post-operation in cardiac surgery, and low dose continuous infusion of alpha-hANP from staring on cardiopulmonary bypass will be expected as a newly application.

Aldosterone↗
PubMed1999

Surgical treatment of 22 cardiac myxomas: A review.

Twenty-two cases of cardiac myxomas were reviewed. The patients were 8 men and 14 women ranging in age from 12 to 73 (mean: 50.8 +/- 16. 6) at operation. They suffered from dyspnea, palpitation, and cough, similar to mitral disease symptoms, and cerebral emboli in 6 patients (30%) with left atrial myxomas. Echocardiography, especially transesophageal, was useful in diagnosing cardiac tumors and location. In 20 cases, tumors were at the left atrium and at the right in 2. Left atrial myxomas were approached through a septal incision in 17 cases; a large circular incision of the biatrium was used in 3 patients with large tumors or mitral regurgitation. Left atrial myxomas were attached to the atrial septum in 17 cases, the posterior wall of the left atrium in 2, and near the posterior commissure of the mitral valve in 1. Right atrial myxomas were attached to the atrial septum in 1 and posterior wall beside the inferior vena cava in 1. Resected myxomas weighed from 10 to 90 (mean: 39.1 +/- 19.1) g. No correlation was seen between features such as neurologic symptoms, feeding artery on coronary angiography, or functional status and tumor weight. No recurrence was seen.

Adolescent↗
PubMed1999

Noninvasive system for evaluating the allergen-specific airway response in a murine model of asthma.

In the present report, we show that the enhanced pause (Penh), a novel indicator of airway responsiveness to bronchoconstrictors, can also be a good marker of airway response to an allergen challenge in a murine model of asthma. Male BALB/c mice were sensitized with ovalbumin (OVA) through a combination of intraperitoneal injection and aerosol inhalation. After this immunization, the OVA-specific IgE titer in serum increased to a significantly higher level than in a saline/PBS-treated control group. After the final OVA aerosol challenge, Penh was repeatedly measured in conscious, unrestrained mice, according to the time schedule. Penh increased gradually after the challenge and reached a maximal value at 24 hours that was significantly higher than the control value (p < 0.01). Histologic examination of the lung revealed airway inflammation with an invasion by eosinophils and lymphocytes from vessels into the peribronchial interstitium and the mucosal and submucosal areas of the bronchus. There was a strong correlation between the Penh value and eosinophil number in bronchoalveolar lavage fluid (r = 0.699, p < 0.0001). Moreover, Penh also correlated strongly with the intensity score of histologic findings. These results suggest that the bronchial response to a specific allergen could be followed in a particular individual through the noninvasive Penh method, and that Penh accurately reflects the intensity of eosinophilic bronchial inflammation. This system would be applicable to a noninvasive, chronological evaluation of various experimental interventions in a murine model of asthma.

Allergens↗
PubMed1998

Isolation and characterization of a rice cDNA encoding the gamma-subunit of translation elongation factor 1B (eEF1Bgamma).

We isolated a rice cDNA clone (refg) encoding the gamma-subunit of translation elongation factor 1B (eEF-1B gamma; the old designation was EF-1 gamma). The refg encodes an open reading frame of 419 amino acids which shows a similarity to the equivalent sequences from animals and yeast. Complex formation analysis, which showed the recombinant protein of refg (His-eEF1B gamma) and formed a complex with GST-eEF-1Bbeta, indicated that the refg encodes rice eEF1B gamma of the eEF1B alphabeta gamma complex. Expression analysis showed that refg mRNA is very abundant in suspension-cultured cells during the exponential phase of growth. A DNA blot analysis indicated that refg is located at a single locus in the rice genome.

Amino Acid Sequence↗
PubMed1998

Synthesis and pharmacological characterization of novel 6-fluorochroman derivatives as potential 5-HT1A receptor antagonists.

A series of novel 6-fluorochroman derivatives was prepared and evaluated as antagonists for the 5-HT1A receptor. N-2-[[(6-Fluorochroman-8-yl)oxy]ethyl]-4-(4-methoxyphenyl)butylami ne (3; J. Med. Chem. 1997, 40, 1252-1257) was chosen as a lead, and structural modifications were done on the aliphatic portion of the chroman ring, the tether linking the middle amine and the terminal aromatic ring, the aromatic ring, and lastly the amine. Radioligand binding assays proved that the majority of the novel compounds behaved as good to excellent ligands at the 5-HT1A receptor, some of which were selective with respect to alpha1-adrenergic and D2-dopaminergic receptors. The antagonist activity of the compounds was assessed in the forskolin-stimulated adenylate cyclase assays in CHO cells expressing the human 5-HT1A receptors. Among the modifications attempted, introduction of an oxo or an optically active hydroxy moiety at the chroman C-4 position was effective in ameliorating the receptor selectivity. Six analogues were selected through the in vitro screens and further evaluated for their in vivo activities. A 4-oxochroman derivative (31n), having a terminal 1, 3-benzodioxole ring, demonstrated antagonist activities toward 8-OH-DPAT-induced behavioral and electrophysiological responses in rats.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1998

A five-alpha reductase inhibitor or an antiandrogen prevents the progression of microscopic prostate carcinoma to macroscopic carcinoma in rats.

BACKGROUND: The objective of this study was to elucidate the prophylactic effects of 5-alpha reductase inhibitor (e.g., finasteride) and a pure antiandrogen (e.g., casodex) on rat prostate carcinogenesis and to determine whether latent prostate carcinoma can be prevented to develop to clinically significant cancer by use of these drugs. METHODS: F344 rats were subcutaneously administered 3,2'-dimethyl-4-aminobiphenyl (DMAB) for the first 20 weeks and testosterone propionate throughout the 60-week study. Finasteride (5 mg/kg and 15 mg/kg, 2 times per week) and casodex (15 mg/kg, 30 mg/kg, and 60 mg/kg, 3 times per week) were administered orally during the last 40 weeks of the study. Tumors were classified as visible prostate carcinoma when they could be recognized with the naked eye and as microscopic prostate carcinoma when detectable only with a microscope. RESULTS: The incidence of visible prostate carcinoma was 51% (18 of 35 rats) in the positive control group, whereas it was 40% (4 of 10 rats) in the finasteride 5 mg/kg group, 16.7% (2 of 12 rats, P = 0.0091) in the finasteride 15 mg/kg group, 20% (4 of 20 rats, P = 0.05) in the casodex 15 mg/kg group, 14.3% (3 of 21 rats, P = 0.0008) in the casodex 30 mg/kg group, and 0% (0 of 11 rats, P = 0.0002) in the casodex 60 mg/kg group. On the other hand, when visible carcinomas and microscopic carcinomas were handled together, only casodex 60 mg/kg significantly inhibited the carcinogenesis rate. CONCLUSIONS: Finasteride achieved dose-dependent inhibition of macroscopic rat prostate carcinogenesis, and casodex also inhibited macroscopic prostate carcinogenesis. However, both drugs showed insufficient prevention of carcinogenesis at the microscopic level. These findings indicate that, in clinical medicine as well, such drugs may also be able to prevent the progression of latent prostate carcinoma to life-threatening disease.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1998

Effects of concomitant usage of milrinone and catecholamine for weaning from cardiopulmonary bypass.

To estimate the effectiveness of concomitant usage of milrinone and catecholamine for weaning from cardiopulmonary bypass (CPB), a clinical study was made, in elective coronary artery bypass grafting (CABG) cases. 24 consecutive patients underwent elective CABG in our institute. In all cases, moderate hypothermia and cardioplegic(St. Thomas solution) cardiac arrest were performed. In 12 cases, continuous intravenous 0.25 microgram/kg/min of milrinone, 3 micrograms/kg/min of dobutamine (DOB) and dopamine (DOA) as the initial doses, were used concomitantly as inotropic agents (Group-I). The same initial doses of catecholamine (DOB and DOA) as the Group-I were administered in another 12 patients (Group-II). When the pump flow of CPB decreased to a half, these drugs were administered in both groups. Hemodynamic data were measured before CPB, just after operation, 3, 6, 12, 24, 48, and 72 hours after operation. There were no significant differences in aortic and pulmonary artery pressure between both groups. However, cardiac index (CI) of the Group-I demonstrated significantly (p < 0.01) higher values than that of Group-II until 24 hours after surgery. Systemic vascular resistance index (SVRI) of the Group-I demonstrated significantly (p < 0.01) lower value than that of Group-II from 3 to 12 hours after operation. There were no significant differences in oxygen delivery (DO2) and oxygen consumption (VO2) between both groups. These results suggested that concomitant usage of milrinone and low dose catecholamine increased CI and decreased SVRI, and made weaning from CPB very easy, demonstrating excellent hemodynamics. This high potential phosphodiesterase inhibitor may be suitable for not only weaning from CPB but also post-cardiotomy cardiogenic shock.

Cardiopulmonary Bypass↗
PubMed1998

Neuroprotective effect of YM-39558 in focal cerebral ischemia in cats.

We studied the effect of YM-39558, orotic acid ethylester, in a focal cerebral ischemia model in anesthetized cats. YM-39558 has good permeability across the blood brain barrier, and in the brain is hydrolyzed to orotic acid, the main active substance. Cats were subjected to permanent occlusion of the middle cerebral artery (MCA) for 6 h, then killed and examined histologically. Treatment with YM-39558 (intravenous infusion of 11.8 mg (10 mg as orotic acid)/6 ml per kg per h) starting 15 min after MCA occlusion markedly reduced the volume of ischemic damage (from 2450 +/- 82 mm3 of the cerebral hemisphere in the saline-treated cats to 1644 +/- 123 mm3 in the YM-39558-treated cats, P < 0.01). In contrast, YM-39558 (2.26 and 1.18 mg/0.8 ml per kg per h) showed no significant protective effect on ischemic damage. No significant differences were observed between saline- and YM-39558-treated cats concerning physiological variables including brain temperature. This evidence for the neuroprotective efficacy of YM-39558 in gyrencephalic species suggests its therapeutic potential in the treatment of stroke in humans.

Animals↗
PubMed1998

Clinical experiences of percutaneous cardiopulmonary support: its effectiveness and limit.

In recent years, several types of centrifugal pumps have been widely used as the main pumps for cardiopulmonary bypass (CPB) and postcardiotomy cardiac support. From April 1990 to March 1997, a percutaneous cardiopulmonary support (PCPS) system was used in 20 patients with an average age of 58 years (13 males and 7 females). They comprised 11 ischemic, 6 valvular, 2 aortic, and 1 congenital heart disease patients. Our PCPS system consists of a centrifugal pump (BioMedicus BP-80), an oxygenator, and a reservoir. The entire blood contacting surface, including that of the thin wall cannulas, is coated by heparin bonded materials. As a result of this new technology, this system can be used for the long term without systemic heparinization. No major critical thrombi were revealed inside the pumps or circuits. Of the 20 patients, 7 (35%) (Group 1) could be weaned from PCPS, and the remaining 13 (Group 2) could not. In Group 1 although 2 patients suffered from renal failure and pneumonia, respectively, both were discharged from our hospital. The long-term survival rate was 35%. In Group 2 cerebral vascular damage was recognized in 3 patients, renal failure in 4, multiple system organ failure in 4, bleeding in 2, arrhythmia in 1, and leg ischemia in 2. Pulse pressure was significantly elevated due to the recovery of the native heart in Group 1, 2 days after support. However, in Group 2, it did not elevate, and the left ventricular ejection fraction was less than 30%, associated with high left atrial pressure. In conclusion, this heparin coated PCPS system was very simple and easy to control. It demonstrated long-term biocompatibility and was very effective in recovering deteriorated cardiac function. Quicker application of this system can play an important role in preventing severe complications and obtaining better clinical results. If long-term support is necessary, a ventricular assist device (VAD), which is more powerful, durable, and biocompatible, has to be applied instead of PCPS.

Acute Kidney Injury↗
PubMed1998

Spontaneous pneumothorax complicating lung metastasis from lingual carcinoma.

We report a patient with pneumothorax caused by a metastatic tumour from carcinoma of the tongue, which had given rise to a bronchopleural fistula with subsequent induction of pneumothorax. Although rare, pulmonary metastasis should be considered in the aetiology of spontaneous pneumothorax. Despite advanced disease, surgical treatment may be feasible.

Carcinoma, Squamous Cell↗
PubMed1998

Neutropenic colitis as a complication of high-dose chemotherapy for refractory testicular cancer.

A 44-year-old man received high-dose chemotherapy with carboplatin, etoposide and cyclophosphamide followed by autologous peripheral-blood stem-cell transplantation for treatment of refractory nonseminomatous testicular cancer (seminoma plus choriocarcinoma). The patient developed fever, watery diarrhea and abdominal pain at 10 days after the initiation of high-dose chemotherapy. Radiological examinations revealed adynamic ileus with thickened colon and small bowel wall and increasing ascites over the next 3 days. The patient subsequently suffered from disseminated intravascular coagulation, renal failure and hyperbilirubinemia despite systemic antibiotic therapy. Intensive medical care could barely avoid the fatal outcome. Neutropenic colitis has been recognized as a complication of acute leukemia or aplastic anemia. The present case indicates that this serious gastrointestinal complication can occur under profound neutropenic conditions induced by intensive chemotherapy for solid cancer.

Adult↗
PubMed1998

Neuroprotective effect of YM-39558, orotic acid ethylester, in gerbil forebrain ischemia.

We studied the effects of orotic acid and YM-39558 (2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acid ethyl ester), orotic acid ethylester, on delayed neuronal death of hippocampal CA1 neurons induced by transient forebrain ischemia. Our data indicated that YM-39558 had high permeability across the blood brain barrier and was hydrolyzed to orotic acid, the active substance, in the brain. The neuronal damage was reduced significantly in animals intraperitoneally treated with YM-39558 (100 mg/kg x 3) after ischemia, but not with orotic acid in the same way. The results also suggested that the maintenance of a few ten micromolar orotic acid in cerebrospinal fluid were needed for its neuroprotective effects.

Animals↗
PubMed1998

Coronary artery surgery results 1996.

This survey on ischemic heart disease surgery began in 1974 and has continued to report the current status of surgical treatment in Japan. Coronary artery bypass grafting (CABG) has increased markedly and surgical results have become increasingly favorable. This report describes CABG and surgery for postinfarction complications in 1996, including the first investigation on CABG without cardiopulmonary bypass (off-pump CABG) and minimally invasive direct coronary artery bypass grafting (MIDCAB).

Coronary Artery Bypass↗
PubMed1998

Left atrial myxoma with an atrial septal defect: a case report and review of the literature.

We report a case of a 49 year-old Japanese woman with a left atrial myxoma complicated by an atrial septal defect diagnosed intraoperatively, which was classified as in secundum defect and was 28x110 mm in diameter. The tumor, which was attached by a pedicle to the posterior wall of the left atrium near the posterior commissure of the mitral valve, was removed together with a small portion of the left atrial wall. The postoperative course was uneventful. The pathologic findings were consistent with the diagnosis of myxoma. Since the defect was functionally canceled by the myxoma, the diagnosis of an atrial septal defect was not confirmed preoperatively even by color Doppler echocardiography and cardiac catheterization. Tumor embolization is one of the critical complications of myxoma. Fortunately, she didn't suffer from either systemic or pulmonary emboli. During surgery of myxoma with atrial septal defect, careful manipulation is needed, especially at caval cannulation so as not to damage the tumor directly. In the cases with atrial septal defect or patent foramen ovale, myxomas are generally situated on the interatrial septum. However, in this case the tumor was located on the posterior wall of the left atrium.

Cardiac Catheterization↗