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S Tsukamoto

Publications and source records attributed to S Tsukamoto.

At least 37 records · Page 2Linked to original sources
PubMed2000

Promoting effects of antiandrogenic agents on rat ventral prostate carcinogenesis induced by 3,2'-dimethyl-4-aminobiphenyl (DMAB).

The objective of this study was to determine the effects of androgen depletion by 5alpha-reductase inhibitor (eg epristeride), pure antiandrogen (eg casodex) or C17-20 lyase inhibitor (eg YM116) on rat prostate carcinogenesis induced by administration of 3,2'-dimethyl-4-aminobiphenyl (DMAB). DMAB was subcutaneously administered on male F344 rats for the first 20 weeks. Epristeride (10 and 50 mg/kg, three times per week), casodex (15 and 30 mg/kg, three times per week) or YM116 (15 and 30 mg/kg, three times per week) were administered orally for 40 consecutive. Then, all accessory sex organs were studied for the formation of neoplastic lesions by histological examination. All carcinoma lesions were produced only in the ventral lobe of the prostate. The incidence of carcinoma developing in the ventral lobe of the prostate was 9.5% in the control group on which DMAB alone was administered, whereas it was 31.6% in the epristeride 10 mg/kg group. 45.0% in the epristeride 50 mg/kg group, 47.8% in the casodex 15 mg/kg group, 63.2% in the casodex 30 mg/kg group, 10.5% in the YM116 15 mg/kg group and 5.0% in the YM116 30 mg/kg group. The incidences of carcinoma in the epristeride 10 mg/kg group, casodex 15 mg/kg group and casodex 30 mg/kg group were significantly higher than that of the control group. In this experimental model, all ventral prostate carcinomas were in situ adenocarcinomas that did not form palpable nodules or distant metastasis. Epristeride and casodex showed a dose-dependent promoting effect on rat ventral prostate carcinogenesis. These results were contradictory to the results of our previous studies; exogenous testosterone in combination with DMAB produced palpable, and metastatic tumors in other portions of accessory sex organs of F344 rats but no carcinoma in ventral prostate, and those invasive carcinomas were significantly inhibited by 5alpha-reductase inhibitor and nonsteroidal anti-androgen. The action mechanisms of androgen and the effects of androgen-regulatory drugs on prostate carcinogenesis should be further studied. Prostate Cancer and Prostatic Diseases (2000) 3, 115-119

Journal Article↗
PubMed2000

Removal of a chronically infected bipolar pacemaker electrode: a successful case report.

A chronic infected bipolar pacemaker electrode with a fin tip was successfully removed 7 years and 9 months after its original implantation from a 72-year-old Japanese man, using the Cook pacemaker lead extraction system. The locking stylet could not advance to the lead tip over the positive pole because of firm adhesions. Because the scar tissue between the positive pole and myocardium could not be freed by the inner sheath, it was disrupted by the slanted end of the outer sheath. The firmest adhesion was on the positive pole, not on the fin tip. The complete extraction success rate of bipolar tined or fin leads is worse than for other types of leads. When extracting a bipolar pacemaker lead, dissection of the positive pole from scar tissue should be taken into account in addition to the lead tip. Rotating the slanted end of the outer sheath is a useful technique when dissecting firm adhesions.

Aged↗
PubMed2000

[Evidence-based medicine for urological cancer chemotherapy].

We reviewed the treatment results of urological cancer chemotherapy from the standpoint of evidence based medicine. In the treatment of advanced transitional cell carcinoma of the urothelium, M-VAC (MTX + VBL + ADM + CDDP) is regarded as the standard regimen; however, durable event-free survival is rare. There is no level 1 evidence to date showing that the use of neoadjuvant or adjuvant cisplatin-based regimens will improve survival in cases of locally advanced bladder cancer. Immunotherapy with interferon or interleukin-2 produces a small survival advantage in patients with metastatic renal cell carcinoma. There is no evidence that adjuvant interferon-alpha administration will improve the survival in those with non-metastatic renal cell carcinoma. Systematized cisplatin-based treatment protocols have been established in patients with advanced testicular germ cell tumor by means of many randomized controlled trials. Several clinical trials are under way to prove the efficacy of high dose chemotherapy (with autologous stem-cell support) in patients with poor risk germ cell tumors. We do not yet have sufficient data to conclude whether maximal androgen blockade will prolong the survival in patients with metastatic prostate cancer, nor to conclude whether neoadjuvant androgen depletion treatment improve disease free survival of the patients after radical prostatectomy.

Carcinoma, Transitional Cell↗
PubMed2000

Closure of calcified patent ductus arteriosus.

Patent ductus arteriosus (PDA) in adults is occasionally associated with calcification and pulmonary hypertension, for which an anterior approach through a median sternotomy with cardiopulmonary bypass is often used. Sutures are placed without circulatory arrest by using a transpulmonary balloon catheter as an occluder. To secure the suture tie, we used Nélaton's catheters as tourniquets.

Calcinosis↗
PubMed2000

[A case of epithelial cancer of the alveoli which responded favorably to the additional administration of UFT for refractory cancer after administration of carboplatin and docetaxel].

Epithelial cancer of the alveoli is considered to be a pulmonary non-small cell carcinoma which responds poorly to carcinostatics. In one case of epithelial cancer of the alveoli which metastasized to both lungs and caused breathing to deteriorate rapidly, chemotherapy was applied with 500 mg of carboplatin (CBDCA) and 90 mg of docetaxel (TXT). Although the tumor was reduced initially, it was found to have been aggravated again three weeks after the start of the chemotherapy. In the second and third courses of the chemotherapy, CBDCA and TXT were administered in the same dosage as in the initial course, but with the oral administration of UFT (600 mg/day). The results were favorable, as evidenced by the absence of recurring aggravation. Currently, the patient has been followed on an outpatient basis for over six months with the administration of UFT. Good QOL is being maintained without any repeated aggravation of the tumor.

Administration, Oral↗
PubMed2000

Operative management of abdominal aortic aneurysm with left-sided inferior vena cava.

Abdominal aortic aneurysm with left-sided inferior vena cava (IVC) is rare. In preoperative examination, it is important to conduct roentgenologic studies and determine any venous anomalies. Proximal anastomosis is technically difficult because the IVC crosses to the right on the aneurysmal neck. In this case of a 71-year-old Japanese man, proximal anastomosis was conducted safely under wide vena cava mobilization and contraction in the superior direction. In vein resection, vessels should be reconstructed because vein communication is not methodical.

Aged↗
PubMed2000

[Serum soluble interleukin-2 receptor levels in patients with renal cell carcinoma: a comparison of values before and after surgery].

This study was carried out in order to find out whether soluble interleukin II receptor (sIL-2R) levels were useful as a treatment biomarker in patients with renal cell carcinoma (RCC). The subjects consisted of 17 patients with RCC who had been scheduled for radical or partial nephrectomy. Serum levels of sIL-2R were measured before surgery and 1 and 3 months after surgery. We also analyzed the relationship of preoperative sIL-2R to pathologic TNM-stage, grading and presumptive tumor volume. The mean value of pre-operative sIL-2R in patients with RCC was 496.5 U/ml as compared with 302.7 U/ml in the control group (p = 0.056). Pre-operative sIL-2R values were 411.1 U/ml in stage I (n = 6), 481.4 U/ml in stage III (n = 11) and 1,330 U/ml in stage IV (n = 1). There was no significant difference between stage I and stage III. As compared with pathologic grading, pre-operative sIL-2R levels in patients with grade 2 were significantly higher than those with grade 1 (609.8 U/ml versus 288.7 U/ml, p = 0.016). There existed a significant correlation between preoperative sIL-2R and presumptive tumor volume (r = 0.61, p = 0.008). Three months after surgery, sIL-2R values were significantly higher than before surgery. Serum sIL-2R levels seemed to bear some relationship to the extent of disease in patients with RCC. Values of sIL-2R were significantly higher after than before surgery at least for a three-month postoperative period, suggesting a response to trauma of surgery. Further long term studies were required to clarify if sIL-2R could predict the progression of disease.

Adult↗
PubMed1999

Elimination of Kupffer cells and nafamostat mesilate rinse prevent reperfusion injury in liver grafts from agonal non-heart-beating donors.

BACKGROUND: We hypothesized that microcirculatory disturbance was an obstacle to liver transplantation (LTx) from non-heart-beating donors (NHBDs) and that it was attributed mainly to a deterioration of sinusoidal endothelial cells (SECs) and sinusoidal narrowing. This study was designed to examine porcine orthotopic LTx using livers obtained from pretreated agonal NHBDs, and to determine whether the maintenance of the liver microcirculation would result in successful LTx from agonal NHBDs. METHODS: Pigs were allocated to five groups: (i) control group; (ii) NM group, in which grafts were rinsed with nafamostat mesilate (NM) rinse; (iii) LD group, in which Kupffer cells in grafts were eliminated by liposome-encapsulated dichloromethylene diphosphonate (L-DMDP); (iv) LDNM group, in which grafts pretreated with L-DMDP were rinsed with NM rinse; (v) heart-beating donor (HBD) group. In all groups, but the HBD group, the livers were pretreated with FK506 and prostaglandin I2 analogue, and were preserved in University of Wisconsin solution after cardiac arrest. Thereafter orthotopic LTx was performed. RESULTS: After reperfusion, it was histologically demonstrated that elimination of Kupffer cells prevented SECs deterioration and NM rinse prevented sinusoidal narrowing. The hepatic energy charge recovered in all groups except the control group. In the LDNM group, three of four recipients survived more than 7 days. CONCLUSIONS: For a successful LTx from agonal NHBDs, it is important to prevent microcirculatory disturbance caused by SEC deterioration and sinusoidal narrowing after reperfusion. Combination therapy consisting in the elimination of Kupffer cells and NM rinse prevented primary graft non-function in liver grafts from agonal NHBDs.

Adenosine Triphosphate↗
PubMed1999

The mechanism of injury in a steatotic liver graft during cold preservation.

BACKGROUND: Fatty livers are more prone to primary nonfunction after transplantation. It is known that cell injury is strongly associated with alterations in the content and composition of membrane lipids. We assumed that plasma membrane (PM) fluidity, which is the most important property of the membrane, differed between fatty and normal livers. METHODS: The livers from obese and lean Zucker rats were flushed with cold Ringer's lactate and University of Wisconsin (UW) solution via the portal vein and preserved in cold UW solution for 24 hr. Histological examinations of electron microscopy were performed to investigate of sinusoidal lining cells (SLCs). PMs were isolated using a discontinuous density gradient of Percoll, and the lipid compositions were determined by chromatography. RESULTS: SLCs of fatty livers were markedly injured compared with control livers even after short preservation time. Moreover, many blebs were observed in the obese rats even after short preservation time. As for PM lipid composition, the cholesterol/phospholipid (PL) ratio of total PM was 0.14+/-0.03 in the obese rats and 0.21+/-0.03 in the lean rats (P<0.05). The relative proportions of polyunsaturated fatty acids among PLs in PM were 35.7+/-1.2% vs. 45.9+/-1.5% (P<0.0001). These results indicated that the fluidity of the PM in the obese rats is decreased after exposure to low temperatures. CONCLUSIONS: Our results suggest that steatotic livers from obese donors are more susceptible to cold preservation injury than livers without steatosis because of the severe deterioration of SLCs, and it is associated with PM fluidity even after short-term cold preservation.

Adenosine↗
PubMed1999

Lumichrome. A larval metamorphosis-inducing substance in the ascidian Hhalocynthia roretzi.

It has long been known that metamorphosis of ascidian larvae is induced by exposure to adult tunic extract or larval-conditioned seawater. However, such a natural 'inducer' has not been identified, probably due to its very low concentration in organisms. Here we have succeeded in isolating the same metamorphosis-inducing substance from the larvae, the larval-conditioned seawater, and the adult tunic of the ascidian Halocynthia roretzi. Structural analysis revealed that this substance was identical to lumichrome. Lumichrome was active toward H. roretzi larvae, but inactive toward another ascidian larvae, suggesting that lumichrome is species-specific. Riboflavin (vitamin B2), from which lumichrome might be derived from, was found to be inactive in induction of larval metamorphosis. In addition, it was demonstrated that lumichrome is localized predominantly in the basal region of the adhesive organ and the posterior part of the larval trunk. Thus, we propose that lumichrome functions as a natural inducer for larval metamorphosis in H. roretzi. This is the first natural metamorphosis-inducing substance to be identified in ascidians.

Animals↗
PubMed1999

Cytokine and endothelial damage in pulsatile and nonpulsatile cardiopulmonary bypass.

Recently, several types of centrifugal pumps have been widely used as the main pumps for cardiopulmonary bypass (CPB). However, according to the results of our experimental studies, after cardiogenic shock, pulsatile flow was effective in maintaining the functions and microcirculations of end organs, especially those of the liver and kidney. To estimate the effectiveness of pulsatility during CPB, cytokine and endothelin and other metabolic parameters were measured in clinical pulsatile and nonpulsatile CPB cases. From March to May 1997, CPB was performed in 18 elective cases (14 ischemic and 4 valvular disease). In 9 cases, pulsatile perfusion was achieved by the Jostra HL20, which is a newly developed CPB pump (Group P). A nonpulsatile centrifugal pump was used in 9 patients (Group NP). In both groups, as chemical and metabolic mediators, interleukin-8 (IL-8), endothelin-1 (ET-1), and plasma free hemoglobin were measured before and during CPB, and 0.5, 3, 6, 9, 18 h after weaning from CPB. This pulsatile CPB pump could be very simply and easily controlled and could easily produce pulsatile flow. There were no significant differences in CPB time (CPBT), aortic cross clamp time (ACCT), mean aortic pressure, or pump flow during CPB between the both groups. The ET-1 level of Group P was significantly (p < 0.05) lower than that of Group NP 9 h after CPB weaning. The IL-8 level of Group P also showed a lower value than that of Group NP. As for plasma free hemoglobin, there were no significant differences between the groups. These results suggested that even in conventional CPB, pulsatility was effective to reduce endothelial damage and suppress cytokine activation. It may play a important role in maintaining the functions and microcirculations of end organs during CPB.

Aged↗
PubMed1999

Invasive thymoma with long-term survival by extensive reoperation.

The recurrence of invasive thymoma is often observed; however, no accepted treatment of recurrent invasive thymoma has yet been established. We herein report a 41-year-old woman with invasive thymoma and pleural dissemination who demonstrated long-term survival after undergoing 4 operations. Based on our findings, reoperation is thus suggested in patients with intrathoracic recurrence and long-term survival can be expected.

Adult↗
PubMed1999

[Marine natural products influencing larval settlement and metamorphosis of marine sessile organisms].

Most marine sessile organisms have a planktonic larval phase in their life cycles, and then larvae settle and metamorphose into their adult forms. The selection of settlement sites is a critical event for these organisms because settlement on unsuitable places affects their survivorship severely. Ascidians live gregariously, and conspecific chemical cues are thought to play an important role in gregarious settlement of larvae. The extracts of conspecific adults or larvae have been claimed to contain "natural metamorphosis inducers." Little is known, however, about their chemical properties. To discover natural signal substances for larval metamorphosis in ascidians, we surveyed the metamorphosis-inducing activity of the medium conditioned by ascidian larvae, and succeeded in isolating a metamorphosis-inducing substance from the conditioned medium of Halocycthia roretzi larvae and found that it was identical to lumichrome. We have also isolated more than 40 active metabolites, which may mimic lumichrome, from marine sponges. On the contrary, marine sessile organisms cause serious problems by settling on fishing nets, hulls of ships, and cooling systems of power plants. Organotin compounds have been widely used for the control of these organisms, but they are known to be toxic to marine biota. Therefore, nontoxic antifouling substances are urgently needed. Marine sessile organisms possess chemical defense systems using their secondary metabolites, which might be potential by nontoxic antifouling agents. We have attempted to obtain antibarnacle substances from marine sponges and isolated 26 antifoulants.

Animals↗
PubMed1999

Effects of phosphodiesterase inhibitors after coronary artery bypass grafting.

The aim of this study was to estimate the postoperative effects of phosphodiesterase (PDE) inhibitors (milrinone and olprinone) after coronary artery bypass grafting (CABG). To prevent hypotension caused by the PDE inhibitors, low dose of catecholamines were used concomitantly. A total of 34 elective CABG cases were tested. In 12 cases, 0.25 microg kg(-1) min(-1) of milrinone, 3 microg kg(-1) min(-1) of dobutamine (DOB) and dopamine (DOA) were used concomitantly (Group-M). In another 10 patients, 0.1 microg kg(-1) min(-1) of olprinone and the same doses of the catecholamines were infused (Group-O). As a control, the same doses of DOA and DOB only were administered in 12 patients (Group-C). When the pump flow of the cardiopulmonary bypass (CPB) decreased to half, these drugs were given in all groups. Hemodynamics were recorded before CPB, just after the operation, and 3, 6, 12, 24, 48 and 72 h after the operation. Both milrinone and olprinone increased the cardiac index and decreased systemic vascular resistance to almost the same degree. Olprinone decreased mean aortic and pulmonary artery pressures, and also significantly reduced the preload of both right and left heart compared with milrinone. Significant hypotension was not detected due to the concomitant usage of low-dose catecholamines. This concomitant usage of PDE inhibitors and catecholamines allowed easy weaning from CPB, demonstrating excellent hemodynamics after CABG. Good oxygen demand and supply balance were maintained in peripheral tissue. These results suggest that these new PDE inhibitors may be effective not only for weaning from CPB but also for post-cardiotomy cardiogenic shock.

Aged↗
PubMed1999

Should use of the internal thoracic artery be avoided under conditions of low free flow? Postoperative hemodynamic assessment using pulsed Doppler echocardiography.

There are cases in which it is thought advisable to avoid the use of the left internal thoracic artery (LITA) in coronary artery bypass grafting (CABG) due to its low free flow (FF). However, even though the LITA flow is very low, anastomosis without any further maneuvers intraluminally is recommended. The present study investigated the clinical results of CABG, using a LITA with low FF. The 60 cases of CABG were divided into 2 groups: (i) Group L (n = 23), in which LITA FF was less than 20 ml/min; and (ii) Group H (n = 37) in which it was more than 20 ml/min. A comparative study on the basis of coronary angiography and pulsed Doppler echocardiography was performed. In both groups, no LITA graft occlusion was identified, and the 'string sign' was also absent. In the LITA blood waveform, all cases exhibited a biphasic pattern with a higher mid-diastolic and a lower end-systolic component. There were no significant differences in the LITA flow diastolic peak velocity, velocity time integrals and the diastolic/systolic peak velocity ratios. These results suggest that the LITA can be used for CABG even when the free flow is less than 20 ml/min.

Aged↗
PubMed1999

[Progress in oral anti-cancer drug therapy for urological cancer].

We describe the progress in oral anti-cancer drug therapy for urological cancer. Pure antiandrogen (e.g., flutamide) is widely used as a means of maximal androgen blockade (MAB) in the treatment of prostate cancer. However, all series reported in the past several years did not show positive effects on prolongation of the patient's survival. Evaluations by meta-analysis are in progress. As the mechanism of antiandrogen withdrawal syndrome has been recognized, it was widely accepted that antiandrogen should be discontinued when disease progression or PSA elevation becomes evident. Estramustine was recently clarified as an effective therapeutic agent in the treatment of hormone refractory prostate cancer in combination with oral etoposide. Oral etoposide therapy has been tried as a maintenance or a palliative chemotherapy for non-curative or high-risk germ cell tumor. UFT (a compound of tegafur and uracil) is said to be effective for bladder cancer. It has been also suggested that UFT was partly effective as a means of first-line endocrine chemotherapy for advanced prostate cancer and was a promising agent in the treatment of advanced renal cell carcinoma in combination with Interferon-alpha. Usually the age of the patient with urological malignancy, excluding testicular cancer, is high and complicated. For such patients, an aggressive intravenous chemotherapy can not always be used. Therefore, a less aggressive, less toxic chemotherapy with oral drug is often planned to maintain QOL.

Administration, Oral↗
PubMed1999

Spontaneous recanalization of postoperative severe graft stenosis. What is the cause and prognosis of the "string sign" in the internal thoracic artery?

A 68-year-old female with unstable angina was treated surgically. She was referred to the surgical ward by cardiologists because of a diagnosis of unstable angina with three vessel disease. On a coronary angiogram (CAG), 90% stenoses were found in the left anterior descending coronary artery (LAD), circumflex (CX), and right coronary artery (RCA). She received elective coronary artery bypass grafting (CABG), in which the left internal thoracic artery (LITA) was anastomosed to the LAD and reversed saphenous vein grafts (SVG) were made to segment 12 of the CX, and segment 4PD of the RCA, respectively. The postoperative course was uneventful, but postoperative early graftgraphy revealed distal narrowing of the LITA graft as the so-called "string sign". However, one year post surgery, the LITA string sign was not found and its patency had markedly improved on the second graftgram. It is reported that the LITA "string sign" might cause late graft occlusion. However, this LITA graft evidently enlarged the size and increased the flow of the artery in proportion to myocardial blood demand. To our knowledge, it has not been reported that an in situ LITA string sign on postoperative early graftgram has disappeared in the late phase. We hypothesize that the LITA string sign might be caused by several different factors such as flow competition, spasm, and/or technical problems. In any event, the LITA string sign does not cause graft occlusion in the late postoperative period in every case.

Aged↗