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Biomedical subjects

S Sakai

Publications and source records attributed to S Sakai.

At least 199 records · Page 11Linked to original sources
PubMed1997

[Changes in tissue and blood polyamines during N-butyl-N-(4-hydroxybutyl) nitrosamine-induced bladder carcinogenesis in rats].

BACKGROUND: Polyamine are recognized as cell growth factors. We studied in order to determine whether alterations in the levels of tissue and blood polyamines were useful biochemical markers for bladder tumor. METHODS: The concentrations of three polyamines, diamine, spermidine and spermine, in urinary bladder and blood were determined during N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN)-induced bladder carcinogenesis in male F344 rats. At 5 weeks of age, rats were given 0.05% BBN in the drinking water for 20 weeks. RESULTS: BBN induced bladder hyperplasia in 4 of 5 rats at 8 weeks, papillomas in 2 of 5 rats at 12 weeks, and transitional cell carcinoma in all the rats by 20 weeks. The levels of total polyamine in both bladder and blood of the rats during 12-20 weeks were significantly higher than those of the control animals given water alone. The elevation of total polyamine was mainly due to the increase of spermidine of the three polyamines, which was coincident with the incidence of bladder tumors. CONCLUSION: The results indicated that the polyamines are excellent biochemical markers for bladder tumors.

Animals↗
PubMed1997

[Changes in tissue and blood polyamine levels following chemotherapy in rats with urinary bladder carcinoma induced by N-butyl-N-(4-hydroxybutyl) nitosamine in rats].

BACKGROUND: Polyamines are recognized as cell growth factors. We attempted to determine whether alterations in the levels of tissue and blood polyamines were useful biochemical makers for monitoring the efficacy of the chemotherapy for bladder tumors. METHODS: The concentrations of three polyamines of diamine, spermidine and spermine in urinary bladder and blood were determined in male F344 rats with urinary bladder carcinoma induced by N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN), following chemotherapy with cisplatin, methotrexate and pirarubicin. RESULTS: Bladder carcinoma was observed in 5 of 20 rats of the chemotherapeutic group, and 16 of 20 rats of the control group given saline alone. The levels of spermidine, spermine and total polyamine in both bladder and blood of the treated rats were significantly lower than those of the control rats. CONCLUSION: The study suggested that the levels of tissue and blood polyamines could be used as biochemical markers for monitoring the efficacy of the chemotherapy for bladder tumors.

Animals↗
PubMed1997

[A case report of localized fibrous pleural mesothelioma].

A 47-year-old female with localized fibrous pleural mesothelioma arising from the visceral pleura of S2 of rt-upper lobe is reported. We demonstrated an indirect radiographic sign of pedunculation which was the change in position of the mass with the change in patient's position. The tumor was completely extirpated with a partial resection of the adjacent lung tissues through thoracotomy. Histopathologically, the tumor consisted of collagen fibers and small amount of fibroblast. Localized fibrous mesothelioma was recognized as benign with good prognosis. However, a few cases showing recurrence after resection were reported among them. So it was considered that this patient should be followed up carefully.

Female↗
PubMed1997

[Assessment of left ventricular systolic function derived from ECG-gated myocardial SPECT with 99mTc-tetrofosmin: automatic determination of LV epi- and endocardial surface].

Non-invasive assessment of ischemic heart disease requires information of both LV function and myocardial perfusion. Recently, ECG-gated myocardial SPECT with technetium-labeled radiopharma-ceuticals can provide both of them. Gated myocardial SPECT were performed in thirty-three patients with cardiac disease using a two-headed rotating gamma camera system (ADAC; VERTEX), 30-60 minutes after resting injection of 555-740 MBq of 99mTc-Tetrofosmin. Then, the SPECT data were used to determine the LV epi- and endocardial surface, and LV volume for measurement of LVEF was calculated automatically. This entire computational process required only 210 seconds per 16 frame study. Interobserver agreement of EF values obtained from gated SPECT was excellent (r = 0.996, n = 10, p < 0.01). LVEFs obtained from gated SPECT showed good correlation to those calculated from radionuclide ventriculography (MUGA) (r = 0.91, p < 0.01). In conclusion, this automatic method using gated myocardial SPECT data was considered to be useful for assessment of LV function with reproducibility.

Aged↗
PubMed1997

99Tcm-MAG3: a sensitive indicator for evaluating perfusion and rejection of renal transplants.

Radionuclide renography has a role in evaluating perfusion of transplanted kidneys. In the course of rejection, cortical perfusion decreases before urinary excretion changes. Based on the facts that 99Tcm-MAG3 has different pharmacokinetics and shows a higher kidney-to-background count ratio than 99Tcm-DTPA, we postulated that 99Tcm-MAG3 was a sensitive and reproducible agent to measure cortical perfusion of transplanted kidneys. To clarify the feasibility of using 99Tcm-MAG3 to measure the cortical perfusion index (CPI), sequential renography was performed using 99Tcm-DTPA and 99Tcm-MAG3 in 14 patients with stable renal transplants, who had changes in serum creatinine concentration of less than 50% between the two studies. The CPI was calculated with 99Tcm-DTPA and 99Tcm-MAG3 and these were then compared and correlated with concurrent serum creatinine concentration. The CPI with 99Tcm-MAG3 was 1.43 times that with 99Tcm-DTPA in patients with changes in serum creatinine concentration equal to or less than 20%, and regression analysis revealed that the difference in CPI was larger in patients with more severely decreased renal perfusion than in patients with normal or mildly decreased renal perfusion. This preliminary study has indicated that the CPI with 99Tcm-MAG3 is a sensitive index for detecting changes in renal function, and thus is a feasible indicator of cortical perfusion when evaluating the rejection of transplanted kidneys.

Adult↗
PubMed1997

[Prediction of the myocardial contractility improvement on early stage after the revascularization using low-dose dobutamine stress 99mTc-MIBI gated SPECT].

For prediction of recovery of LV contractility, 99mTc-MIBI gated SPECT at rest and that with dobutamine (DOB) loading were performed in 15 patients with myocardial infarction (MI). Regional % uptake (regionalx100/maximal count), % wall thickening [%WT; (ES-ED)x100/ED maximal count], and delta %WT (%WT at DOB stress-%WT at rest) were calculated for each of 8 segments (seg.), including 34 MI out of total 120 seg., which derived from short axis LV count profile. These 34 seg. were divided into two groups, recontractile (18 seg.) and non-recontractile (16 seg.), whether improvement of the wall motion following the intervention (3-5 months) was observed by echocardiography. In the result, there were 7 recontractile seg. in 8 seg. with mildly reduced perfusion (> or = normal mean % uptake-2 S.D.), and there were 11 recontractile seg. in 26 seg. with severe reduced perfusion (< normal mean % uptake-2 S.D.). Moreover, in segments with severely reduced perfusion, there was no significant % uptake difference between recontractile and non-recontractile seg. However, delta %WT of recontractile group (11.1 +/- 4.8%) was significantly higher than that of non-recontractile group (5.7 +/- 2.9%) (p < 0.01). In conclusion, although the improvement of contractility on early stage after the revascularization was sometimes underestimated with only perfusion (% uptake), myocardial DOB response of %WT which were obtained by gated SPECT with MIBI would avoid the underestimation.

Angioplasty, Balloon, Coronary↗
PubMed1997

Contribution of tumor necrosis factor alpha and interleukin-1 alpha on the production of macrophage inflammatory protein-2 in response to respiratory syncytial virus infection in a murine macrophage cell line, RAW264.7.

The production of several inflammatory cytokines, such as murine macrophage inflammatory protein-2 (MIP-2), tumor necrosis factor (TNF), and interleukin (IL)-1, was investigated in response to respiratory syncytial virus (RSV) infection in a murine macrophage cell line, RAW264.7, with special reference to mutual relation of their productions. The kinetics of MIP-2 production showed a trend for a biphasic pattern, that is, MIP-2 levels became detectable from 2 h postinfection (p.i.) and increased markedly until 8 h p.i. Thereafter, this level fell to the same level until 16 h p.i. and then increased again. TNF alpha was also detectable at 2 h p.i. and then increased sharply until 8 h p.i., when the peak level attained. Compared with the levels of MIP-2 and TNF alpha, that of IL-1 alpha/beta, especially IL-1 beta, was lower (ng versus pg/ml order). The presence of anti-TNF alpha or anti-IL-1 alpha antibody did not influence the early phase of MIP-2 production but significantly inhibited the late phase, suggesting that MIP-2 is induced by the combined effects of RSV infection via direct induction and indirectly after initial induction of TNF alpha and IL-1 alpha productions. Although RSV-infected RAW264.7 cells had no alteration in viability compared with mock-infected control, these data demonstrate that RSV is a potent inducer of inflammatory cytokines by direct induction and indirectly via the initial production of other cytokines.

Animals↗
PubMed1997

A case of membranous glomerulonephritis associated with gastric cancer.

We describe a patient with gastric cancer and membranous glomerulonephritis (MGN). The patient, a 61-year-old male, was admitted to our Hospital in May, 1996, because of proteinuria and hyperlipidemia persisting for a year. Laboratory examination filled the criteria of nephrotic syndrome and renal biopsy revealed MGN of stage II. Prednisolone therapy (40 mg/day p.o.) was started, followed by a gradual decrease in proteinuria from 4.5 g/day to 0.1 g/day. Endoscopic examination was performed because of stomach-ache revealed advanced gastric cancer of Borrmann 4. Desiring for a conservative therapy, he was discharged and moved to a hospice. In literature review, MGN is the most frequent lesion among various glomerular diseases associated with malignancy, such as the lung, stomach, and colon, particularly at an elderly ages, and sometimes antedates the detection of malignancy, as in the present case. In several cases with MGN, immune-complexes composed of tumor antigens, such as carcino-embryonic antigen, and antibodies have been reported to deposit in basement membrane of glomeruli, causing MGN. In the renal and gastric cancer tissues of the present case, the presence of three novel tumor-associated antigens, Span-1, Thomsen-Friedenreich antigen (T antigen) and F1 alpha antigen, was examined, using a immuno-peroxidase method. Although none of these three antigens were immuno-stained in the renal tissue, clinical course and literature review suggest that MGN in this patient seems to be associated with gastric cancer, which may have produced MGN-causing tumor antigens other than the three antigens. It should be emphasized that malignancy should be carefully and routinely examined in patients with MGN, particularly at elderly ages.

Glomerulonephritis, Membranous↗
PubMed1997

[Clinical efficacy of post-TUR prophylactic chemotherapy for superficial bladder cancer--the result of co-operative prospective randomized trial].

We have performed a prospective randomized clinical trial of post-operative prophylactic therapy for superficial bladder cancer since October in 1991. The criteria were as follows; age < or = 80 y.o., Ta/T1, TCC G1/G2, without CIS lesion and resectable cancer by TUR. The therapeutic arm was divided into three as follows: arm A intracystic instillation with Epirubicin; arm B: oral administration with 5-FU; arm C: combination of arm A and arm B. The number of registered patients were 20 in arm A, 18 in arm B, and 18 in arm C. The patient characteristics in every group were not significantly different. The prophylactic efficacy of arm A was superior to that in the other two groups.

Administration, Intravesical↗
PubMed1997

Waking and sleeping temporalis EMG levels in tension-type headache patients.

Temporalis muscle activity in tension-type headache subjects (n = 36) and in matched nonheadache controls (n = 36) was evaluated in this study. Subjects' cumulative temporalis muscle activity was recorded every 30 minutes for 3 days and night using an electromyographic recorder. Analysis of variance showed that neither the waking nor the sleeping overall muscle activity levels for these two groups were statistically different. When the waking EMG data were dichotomized into function and nonfunction activities, a significant difference was found between groups during jaw function (i.e., chewing and talking). These data suggest that headache subjects are using their temporalis muscles with less efficiency than nonheadache subjects during function. This elevated EMG is more likely a consequence of pain (via protective splinting or guarding) rather than a cause in tension-type headache sufferers.

Adult↗
PubMed1997

Prognostic value of pleural effusion in patients with non-small cell lung cancer.

This study was performed to determine whether pleural effusion in patients with advanced non-small cell lung cancer (NSCLC) has a negative impact on survival. We evaluated 12 prognostic factors in 197 patients with stage IIIB or IV NSCLC. Each factor was dichotomized, and survival curves calculated by the Kaplan-Meier technique were compared using the log-rank test. The Cox proportional hazards regression model was used to confirm the significance of each prognostic factor selected by univariate analysis. We compared the survival times for stage IIIB with pleural effusion with those of stage IIIB without effusion and stage IV. To determine the impact of the cytological results of the effusion on survival, we compared the survival times for cytologically positive and negative effusions. Univariate analysis identified eight significant prognostic factors: pleural effusion, node status, stage, performance status, weight loss, hemoglobin, albumin, and lactate dehydrogenase. Pleural effusion was selected as a prognostic factor in the multivariate analysis, together with stage, performance status, albumin, and node status. Median survival times for stage IIIB without effusion, stage IIIB with effusion, and stage IV were 15.3, 7.5, and 5.5 months, respectively (P < 0.0001). Survival time for stage IIIB with effusion was significantly different from that of stage IIIB without effusion (P = 0.0129) but not from that of stage IV (P = 0.0797). Among patients with effusion, no significant difference in survival time was observed between cytologically positive and negative effusions. We conclude that pleural effusion in advanced NSCLC is a prognostic factor. Survival time for stage IIIB with pleural effusion is more similar to that of stage IV rather than that of stage IIIB without effusion.

Adult↗
PubMed1996

Central antinociceptive effects of mitragynine in mice: contribution of descending noradrenergic and serotonergic systems.

Mitragynine is a major alkaloidal constituent of young leaves of Mitragyna speciosa Korth, that is known to exhibit narcotic-like activity. In this study, we investigated the roles of central monoaminergic systems in the antinociceptive action of mitragynine by means of the tail-pinch and hot-plate tests in mice. Mitragynine (1.0-10 micrograms) injected i.c.v. exerted a dose-dependent antinociceptive activity in both tests. The activity of mitragynine (10 micrograms, i.c.v.) in the tail-pinch test was antagonized by reserpine, 6-hydroxydopamine plus nomifensine, and p-chlorophenylalnine treatment, whereas the antinociceptive activity of morphine (3 micrograms) given i.c.v. in this test was attenuated by 6-hydroxydopamine plus nomifensine but not by p-chlorophenylalanine treatment. Moreover, the activity of i.c.v. mitragynine was also antagonized by the alpha 2-adrenoceptor antagonist, idazoxan (10 micrograms), and cyproheptadine (1 microgram) administered intrathecally (i.t.). On the other hand, the antinociceptive action of i.c.v. mitragynine (10 micrograms) in the hot-plate test was abolished by reserpine and 6-hydroxydopamine plus nomifensine, but not by p-chlorophenylalanine treatment. This action was also antagonized by i.t. injection of idazoxan (10 micrograms). These results suggest that both descending noradrenergic and serotonergic systems are involved in the antinociceptive activity of supraspinally administered mitragynine on the mechanical noxious stimulation, while the descending noradrenergic system predominantly contributes to the effect of supraspinal mitragynine on the thermal noxious stimulation. The mechanisms underlying the suppressive action of mitragynine on the nociceptive response may differ from those of morphine in mice.

Adrenergic alpha-2 Receptor Antagonists↗
PubMed1996

Inhibition of myocardial endothelin pathway improves long-term survival in heart failure.

Occlusion of the diseased coronary artery in humans causes acute myocardial infarction, survivors of which have a high risk for the development of chronic heart failure. Cardiac myocytes and vascular endothelial cells produce endothelin-1 (refs 2-4), which increases the contractility of cardiac muscle and of vascular smooth muscle cells. Endothelin-1 also exerts long-term effects such as myocardial hypertrophy, and causes cellular injury in cardiac myocytes. Production of endothelin-1 is markedly increased in the myocardium of rats with heart failure, and acute application of an endothelin-receptor antagonist decreases myocardial contractility in such rats, indicating that myocardial endothelin-1 may help to support contractility of the failing heart. But we report here that the upregulated myocardial endothelin system may contribute to the progression of chronic heart failure, because long-term treatment with an endothelin-receptor antagonist greatly improved the survival of rats with chronic heart failure. This beneficial effect was accompanied by significant amelioration of left ventricular dysfunction and prevention of ventricular remodelling, in which there is usually an increase in the ventricular mass and cavity enlargement of the ventricle.

Animals↗
PubMed1996

Pulmonary hypertension caused by congestive heart failure is ameliorated by long-term application of an endothelin receptor antagonist. Increased expression of endothelin-1 messenger ribonucleic acid and endothelin-1-like immunoreactivity in the lung in congestive heart failure in rats.

OBJECTIVES: The purpose of this study was to investigate whether 1) endothelin-1, a potent vasoconstrictor peptide, is involved in progression of pulmonary hypertension caused by congestive heart failure (CHF); and 2) whether long-term treatment with BQ-123, an endothelin receptor antagonist, ameliorates pulmonary hypertension caused by CHF. BACKGROUND: Congestive heart failure accompanies pulmonary hypertension, and the severity of pulmonary hypertension is an important determinant of prognosis. Although we reported that production of endothelin-1 is increased in the failing heart in rats with CHF, it is not known whether production of endothelin-1 in the lung is altered by CHF. METHODS: Congestive heart failure was induced by coronary artery ligation in rats. Expression of preproendothelin-1 messenger ribonucleic acid (mRNA) in the lung and kidney was determined. Endothelin-1 staining (immunoreactivity) in the lung was studied by immunohistochemical analysis. Effects of long-term BQ-123 treatment on the rats were studied. RESULTS: Two weeks postoperatively, CHF accompanied by pulmonary hypertension developed in the rats (CHF rats). Expression of preproendothelin-1 mRNA in the lung was markedly higher in the CHF rats than in the sham-operated rats, whereas that in the kidney did not differ between the two groups. Endothelin-1 staining on the pulmonary vascular endothelial cells was more intense in the CHF rats. BQ-123 treatment over a 2-week period in the CHF rats greatly reduced right ventricular systolic pressure and central venous pressure, but it did not affect blood pressure or left ventricular contractility (peak positive first derivative of left ventricular pressure) in these rats. CONCLUSIONS: Long-term BQ-123 treatment greatly ameliorated pulmonary hypertension in the CHF rats. The present study suggests that endothelin-1 plays an important role in the progression of pulmonary hypertension caused by CHF and that an endothelin receptor antagonist may be a new therapeutic agent for CHF-induced pulmonary hypertension.

Animals↗
PubMed1996

Inhibition of lipid peroxidation by diterpenoid from Podocarpus nagi.

A diterpenoid, totarol (1), from Podocarpus nagi was evaluated as an antioxidant. This diterpenoid inhibited autoxidation of linoleic acid. Mitochondrial and microsomal lipid peroxidation induced by Fe(III)-ADP/NADH or Fe(III)-ADP/NADPH were also inhibited. Nagilactone E (2), a norditerpene lactone isolated from the same source, had no antioxidative activity. Furthermore, totarol protected red cells against oxidative hemolysis. This diterpene was shown to be effective in protecting biological systems against oxidative stresses.

Abietanes↗
PubMed1996

Effects of water ingestion on gastric electrical activity and heart-rate variability in healthy human subjects.

Electrogastrography (EGG) is a method to record electrical activity of the stomach using cutaneous electrodes. Power ratio (PR) is one of the parameters and means the relative change of EGG power of gastric activity from before to after certain stimulations (e.g., meals, water or drugs). Autonomic nervous function is an important modulator of gastric activity, but its relation with the EGG parameters has not been well clarified. We recorded EGG and the R-R interval simultaneously both before and after drinking 150 ml water for 400 s, and spectrally analyzed them using the maximum entropy method in 12 healthy volunteers. We calculated PR from before to after water ingestion, and the power of the high-frequency component of R-R interval variability before (pre-HF) and after water ingestion (post-HF), and their ratio (rHF = post-HF/pre-HF). PR was positively correlated with rHR (r = 0.727; P < 0.05) and negatively correlated with pre-HF (r = 0.706; P < 0.05), and rHF was negatively correlated with pre-HF (r = 0.776; P < 0.05). These results suggest that simultaneous recording of EGG and ECG for frequency domain analysis is necessary to estimate the vagal nervous activity.

Adult↗