Biomedical subjects

S Satoh

Publications and source records attributed to S Satoh.

At least 919 records · Page 51Linked to original sources

PubMedDate not supplied

Renal PGE2 release may not be responsible for captopril-induced renal effects in anesthetized dogs.

We studied the possible role of renal prostaglandins (PGs) in captopril-induced hypotension, renal vasodilation, and increased renin secretion using anesthetized dogs. An intravenous injection of 1 mg/kg captopril significantly decreased blood pressure, increased renal blood flow, and raised the renin secretion rate (RSR). These effects of captopril were similar in indomethacin-pretreated (5 mg/kg, i.v.) and in untreated dogs. Captopril administration did not significantly affect the renal PGE2 secretion rate (p greater than 0.10). These results suggest that under our experimental conditions, captopril-induced hypotension, renal vasodilation, and increased RSR may not be due to renal PGE2 release. This does not rule out the possibility that these effects of captopril may be mediated by alterations in the level of circulating bradykinin.

Animals↗

PubMedDate not supplied

Conversion of angiotensin I to angiotensin II and inactivation of bradykinin in canine peripheral vascular beds.

We studied the effects of angiotensin I (AI), angiotensin II (AII), and bradykinin (BK) on systemic blood pressure and blood flow in the renal, mesenteric, coeliac, external iliac, and internal iliac vascular beds in the presence and absence of the converting enzyme inhibitor captopril in pentobarbital-anesthetized dogs. AI and AII caused dose-dependent pressor responses and blood flow reductions, and BK caused dose-related depressor responses and an increase in blood flow. The pressor response to AI was decreased and the depressor response to BK was potentiated by captopril. However, the effectiveness of captopril was greater when the peptides were injected intravenously than when they were injected intraaortically. The average conversion of AI to AII in the mesenteric, coeliac, external iliac, internal iliac, and renal vascular beds was 45.7, 31.6, 30.6, 28.0, and 8.9%, respectively. The dose ratio of equipotent BK-induced responses before and after captopril in the mesenteric, coeliac, external iliac, internal iliac, and renal vascular beds was 4.6, 3.5, 2.8, 2.5 and 1.4, respectively. This order was similar to that of the percentage conversion of AI to AII. These results suggest that the greatest proportion of angiotensin conversion and BK inactivation occurs in the pulmonary circulation and that the least proportion occurs in the kidney.

Angiotensin I↗

PubMedDate not supplied

Renin release induced by a nonvasoconstrictor dose of phenylephrine is independent of the renal prostaglandin system in anesthetized dogs.

We examined the relationship between prostaglandin (PG) production and renin release induced by a nonvasoconstrictor dose of an alpha-agonist, phenylephrine, in anesthetized dogs. Intrarenal infusion of phenylephrine (1 microgram/min) did not affect systemic blood pressure or renal blood flow, but increased the renin secretion rate about twofold. The effect of phenylephrine on renin release was abolished by the intrarenal infusion of the alpha-antagonist phentolamine (50 micrograms/min), but was not affected by the intravenous administration of the PG synthetase inhibitor indomethacin (5 mg/kg). Urine flow and urinary sodium excretion rate were not altered by phenylephrine. These results suggest that a nonvascular and nontubular alpha-adrenoceptor mechanism, which is independent of the renal PG system, may be involved in renin release.

Anesthesia↗

PubMedDate not supplied

Effects of OPC-8212, a new positive inotropic agent, and dobutamine on left ventricular global and ischemic regional functions and coronary hemodynamics under coronary artery stenosis.

We have investigated the effects of OPC-8212, a new positive inotropic agent, and dobutamine, a known cardioselective inotropic agent, on global left ventricular (LV) and ischemic regional functions in 14 excised canine hearts with a flow-limiting stenosis of the left circumflex coronary artery (LCX) (i.e., 20-25% of control flow). OPC-8212 infusion (n = 7) under LCX stenosis improved cardiac depression [i.e., peak LV dP/dt increased from 1,295 +/- 143 mm Hg/s to 2,669 +/- 266 mm Hg/s (mean +/- SEM) (p less than 0.001)], while myocardial ischemic injury, assessed by myocardial CO2-tension and electrocardiogram (ECG)-ST changes, improved (i.e., delta CO2-tension and ECG-ST deviation decreased from 21.1 +/- 3.6 mm Hg and 3.8 +/- 0.6 mV to 13.3 +/- 2.8 mm Hg (p less than 0.01) and 2.0 +/- 0.7 mV (p less than 0.05), respectively). On the other hand, dobutamine infusion (n = 7) further increased myocardial CO2-tension and ECG-ST deviation [i.e., delta CO2-tension and ECG-ST deviation increased from 14.4 +/- 4.2 mm Hg and 2.5 +/- 1.2 mV to 29.0 +/- 6.0 mm Hg (p less than 0.01) and 4.9 +/- 1.0 mV (p less than 0.01), respectively]. At the same time, peak LV dP/dt clearly improved, but to a lesser degree; from 1,425 +/- 153 mm Hg/s to 2,393 +/- 245 mm Hg/s (p less than 0.001). There was also an increase in percent systolic segment shortening of each corresponding area as with OPC-8212.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Effects of nifedipine on renin release and renal function in anesthetized dogs.

The effects of nifedipine, classed as a calcium entry blocker, on urinary excretion and renin release were investigated in anesthetized dogs. Nifedipine was infused into one renal artery for three consecutive 10-min periods, at incremental rates of 0.3, 1, and 3 micrograms/min. Intrarenal infusion of nifedipine (3 micrograms/min) produced marked increases in urine flow rate (by 200%) and in urinary sodium (by 210%) and potassium (by 40%) excretion rates of the infused kidney without changes in mean systemic blood pressure, heart rate, glomerular filtration rate, and filtration fraction. Urinary osmolarity was slightly decreased by the drug, but this change was not statistically significant. There were no consistent changes in these parameters for the contralateral noninfused kidney. Renin secretion rate was increased to three times the preinfusion level during infusion of the highest nifedipine dose. The blood flow to the infused kidney was increased, and ipsilateral renal vascular resistance was simultaneously decreased upon nifedipine infusion. These results suggest that a nonhypotensive dose of nifedipine causes an increase in renin secretion and that this drug has a striking effect on the reabsorption of sodium and water by the renal tubules.

Animals↗

PubMedDate not supplied

Effects of a non-vasoconstrictor dose of phenylephrine on prostaglandin E2 and renin release in anaesthetized dogs.

Phenylephrine (1 microgram/min) was infused into the renal artery of pentobarbitone anaesthetized dogs. Systemic blood pressure and renal blood flow were monitored. Arterial and renal venous blood samples were collected before and 10 min after the start of the infusion. Plasma prostaglandin E2 concentration and plasma renin activity were measured by radioimmunoassay. This dose of phenylephrine did not affect systemic blood pressure and renal blood flow. However, both prostaglandin E2 and renin secretion rates were increased by the infusion of phenylephrine. These results suggest that renal alpha-adrenoceptors participate in prostaglandin and renin release independent of the changes in systemic blood pressure and renal blood flow.

Anesthesia↗

PubMedDate not supplied

Presynaptic inhibition by serotonin of cardiac sympathetic transmission in dogs.

The effect of serotonin on cardiac sympathetic transmission was investigated in vagotomized and cardiac decentralized dogs. Administration of serotonin in doses of 10-100 micrograms/kg i.v., during the resting unstimulated state caused tachycardia and pressor responses which were inhibited by cyproheptadine but not by guanethidine. The tachycardia was reduced by a beta-adrenoceptor antagonist, bufetolol. Serotonin in doses of 3-100 micrograms/kg depressed the elevated heart rate during maintained electrical stimulation of the cardiac sympathetic nerves. Cyproheptadine did not antagonize the serotonin-induced depression of the stimulation-elevated heart rate, while desipramine attenuated but did not abolish it. Serotonin did not have a significant effect on the heart rate elevated by maintained infusion of noradrenaline. The present results suggest that serotonin-induced depression of heart rate during sympathetic nerve stimulation is due to presynaptic inhibition by serotonin of cardiac sympathetic transmission which is not mediated via 'classic' tryptaminergic receptors.

Animals↗

PubMedDate not supplied

Differential blocking effects of prazosin and yohimbine on pressor responses to neuronally released and exogenously administered noradrenaline in the pithed rat.

The effects of prazosin and yohimbine on pressor responses to sympathetic nerve stimulation and intravenous injections of noradrenaline, phenylephrine and clonidine were examined in pithed rats to determine the postjunctional location of alpha 2-adrenoceptors in the vascular smooth muscle. Prazosin antagonized the pressor responses to phenylephrine and to sympathetic nerve stimulation more effectively than the responses to noradrenaline and to clonidine. Yohimbine antagonized the pressor responses to noradrenaline and to clonidine more effectively than the responses to sympathetic nerve stimulation and to phenylephrine. These results suggest that alpha 2-adrenoceptors as well as alpha 1-adrenoceptors produce vasoconstriction in the rat vasculature and support the hypothesis that alpha 1-adrenoceptors are predominantly located within the neuroeffector junction in contrast to an extrajunctional location of alpha 2-adrenoceptors.

Animals↗

PubMedDate not supplied

In utero evaluation and the long-term prognosis of living infants with cystic hygroma.

OBJECTIVE: The aim is to evaluate the natural course and the long-term prognosis of cystic hygroma following live birth. METHODS: Of 39 cases, 12 were excluded because of either artificial termination or intrauterine treatment. 27 cases were retrospectively classified into 2 groups based on the outcome, and the clinical profiles were compared. The long-term prognosis was analyzed for live births. RESULTS: 5 (18.5%) and 22 (81.5%) cases resulted in live birth and fetal demise, respectively. Both the frequency of hydrops fetalis and the maximum size of the cyst were more significantly associated with a poor prognosis (p < 0.01). Of 5 live births, 3 cases with chromosomal or structural abnormalities were handicapped. CONCLUSIONS: Hydrops fetalis and cyst size are poor prognostic factors, and fetal chromosome and structural malformations should be taken into account when predicting the long-term prognosis.

Chromosome Aberrations↗

PubMedDate not supplied

Effects of subminimal inhibitory concentrations of beta-lactam antibiotics against R-plasmid-bearing bacteria.

The effects of subminimal inhibitory concentrations (sub-MICs) of nine beta-lactam antibiotics [penicillin-G, ampicillin (ABPC), cloxacillin, dicloxacillin, nafcillin, cephalothin, cephradine, cefazolin (CEZ) and cefoxitin] against seven different R-plasmid-bearing gram-negative bacterial strains were tested. Morphological changes, such as filamentous development and lysis, occurred at concentrations considerably lower than the MIC values and the presence of R plasmids did not influence the morphological changes compared with those of Escherichia coli NIHJ, which is non-R-plasmid-bearing. Clear cooperation of ABPC and CEZ with rabbit polymorphonuclear leukocytes PMNs against Pseudomonas aeruginosa and Proteus vulgaris and of CEZ against Salmonella typhimurium was observed, but not against the other strains tested. Therefore, the filamentous bacteria produced as a result of exposure to sub-MICs of antibiotics were not always phagocytosed easily. The ratios between the drug concentrations (microgram/ml) at which the morphological changes began to occur (minimal antibiotic concentration) and the MIC values (microgram/ml) were calculated. A large ratio indicated a wide range of effective concentrations below the MIC value for that antibiotic.

Ampicillin↗

PubMedDate not supplied

How antenatal ultrasound diagnosis of congenital malformations has contributed to fetal outcome: a 22-year review.

We herein reviewed 630 malformed fetuses delivered from 24 weeks of gestation onwards in our institute over the past 22 years. These fetuses were divided into 2 groups: 210 from 1970 to 1982 (group 1) and 420 from 1983 to 1991 (group 2). Twenty-two varieties of congenital malformations were diagnosed antenatally in group 1, whereas 55 additional malformations became diagnosable in group 2. Thirty-four varieties of congenital malformations still remained undiagnosed throughout the 22-year study period. Cases receiving 'fetal therapy' and 'close obstetric care' increased, with statistical significance, from 1.8 to 15.7%, and from 22.9 to 55.7% in groups 1 and 2, respectively. A significant increase was also noted in the survival rate from group 1 (63.3%: 105/166) to group 2 (75.5%: 259/343). This study has revealed that the steady advancement in antenatal diagnosis of congenital malformations, along with great efforts in terms of intensive care, has contributed to improved fetal outcome.

Apgar Score↗

PubMedDate not supplied

Antenatal diagnosis and surgical management of congenital cystic adenomatoid malformation of the lung.

We experienced 12 cases of congenital cystic adenomatoid malformation of the lung (CCAM) including 6 cases diagnosed antenatally. They were classified into three groups according to the clinical manifestations. Group A was associated with hydrops fetalis (n = 3), group B presented with respiratory distress symptoms after birth (n = 6), and group C showed no respiratory symptoms (n = 3). All cases of group A were lost because of hydrops and respiratory failure due to pulmonary hypoplasia. Because a compression of the mass is thought to be a cause of hydrops, this group is considered to be a good indication for fetal treatment. All cases of group B showed progressive respiratory symptoms a few days after birth which were successfully treated surgically. In 2 of 3 cases of group C, the lesions decreased in size both antenatally and postnatally. We conclude that serial sonographic evaluations for fetal CCAM are important. If the fetus develops hydrops, fetal surgery is to be considered. If not, however, fetal surgery should not be done, because some lesions can shrink in size, or even disappear, while others can be treated successfully after birth by lobectomy or even segmentectomy.

Cystic Adenomatoid Malformation of Lung, Congenita↗

PubMedDate not supplied

Clinical characteristics and natural history of antenatally diagnosed fetal uropathy. An analysis of 55 cases.

The clinical characteristics and natural history of 55 cases with antenatally diagnosed fetal uropathy were investigated. Percutaneous aspiration of the fetal pelvic or vesical urine was performed to decompress progressive unilateral hydronephrosis in 2 cases and to evaluate renal function in another 2 cases of bilateral hydronephrosis. As the postnatal diagnosis, upper urinary tract dilatation (hydronephrosis or hydronephroureter, 33 cases) and renal dysplasia (15 cases) made up 87% of all cases. A combination of hydronephrosis in one kidney and renal dysplasia in the other was also found in another 2 cases. Among 35 cases with upper urinary tract dilatation, 27 cases demonstrated pelviureteric junction stenosis and surgical intervention was necessary in 15 cases. In 17 cases with renal dysplasia, spontaneous regression was observed in only 3 cases and surgical intervention by means of percutaneous nephrostomy and nephrectomy was performed in 4 and 6 cases, respectively.

Constriction, Pathologic↗

PubMedDate not supplied

Insulin resistance and the alterations of glucose transporter-4 in adipose cells from cachectic tumor-bearing rats.

BACKGROUND: Insulin resistance may play an important role in cancer cachexia; however, its mechanisms remain to be clarified. METHODS: Cellular mechanisms of insulin resistance in tumor-bearing rats (TBR) were investigated in isolated adipose cells by measuring 3-O-[14C]methyl glucose transport activity and glucose transporter-4 (GLUT4) protein in low-density microsomes at a basal state and in the plasma membrane at an insulin-stimulated state. RESULTS: The insulin-stimulated glucose transport activity in adipose cells from TBR was significantly lower than that of control rats (CTR) (0.51 +/- 0.25 and 2.27 +/- 0.11 fmol/cell/min, respectively). The amount of GLUT4 in low-density microsomes at a basal state and in plasma membrane at an insulin-stimulated state was less in TBR than in CTR. CONCLUSIONS: These data suggest that the insulin resistance seen in the adipose cells of these tumor-bearing rats was caused in part by both a decreased amount of GLUT4 protein in a basal state and a decreased translocation of GLUT4 in response to insulin stimulation.

Adipocytes↗

PubMedDate not supplied

Effect of zaprinast on nitric oxide levels in serum and aortic tissue.

Nitric oxide (NO), which is synthesized from the guanidino nitrogen of l-arginine by nitric oxide synthase (NOS), plays an important role in many physiological and pathological processes. Most of the effects of NO are mediated by cyclic guanosine 3'5 monophosphate (cGMP), which is synthesized by soluble guanylate cyclase (sGC) and degraded by phosphodiesterases (PDEs). Although the NO/cGMP pathway has been extensively studied, remarkably little is known about the regulation of NO release. Furthermore, controversial studies have indicated that intervention of the sGC/cGMP pathway modulates the release of NO. The purpose of this study was to evaluate the hypothesis that drugs that affect the sGC/cGMP pathway may modulate NO release and, if so, is there a correlation between NO levels and blood pressure effect? To this end, we investigated the effects of the PDE 5 inhibitor zaprinast on mean arterial pressure (MAP), nitrite/nitrate levels and cGMP in normotensive male Sprague Dawley rats. The results of the current study indicated that zaprinast dose-dependently increased plasma cGMP levels at 18, 24 and 36 mg/kg and decreased MAP at 24 and 36 mg/kg. However, zaprinast at 18, 24 and 36 mg/kg did not affect NO levels either in serum or aortic tissue. We have concluded that the PDE 5 inhibitor zaprinast has no regulatory effect on NO release in serum and aortic tissue, and NO was not involved in the hypotensive effect of zaprinast.

Animals↗

PubMedDate not supplied

Role of pulse wave velocity for assessing autonomic nervous system activities in reference to heart rate variability.

Pulse wave velocity (PWV) is related to arterial wall elasticity, which in part is regulated by sympathetic nervous system activity. The present study investigated the potential for the simultaneous use of PWV and heart rate variability using noninvasive recordings in order to provide a quantitative evaluation of the sympathovagal interaction modulating cardiovascular functions. We obtained 10 indices from the PWV and heart rate (HR) time series of 92 healthy subjects (control group) and compared the results with those of 135 patients with diabetes mellitus or vertigo. Five indices were obtained from a PWV series, that is, the mean, the coefficient of variation (CV) during supine rest, those immediately after standing up unaided, and the change of the mean PWVs before and after standing. The rest of the indices were also obtained from the instantaneous HR series. Statistical analyses revealed significant differences in the change of the mean PWVs after standing, the mean and CV of resting HR, the mean and CV of standing HR, and the change of mean HRs in patients with diabetic neuropathy as compared with healthy subjects (p < 0.01). The change of the mean PWV immediately after standing allows for the assessment of peripheral vascular sympathetic functions, provided one uses HR variability indices simultaneously.

Adolescent↗

PubMedDate not supplied

Efficacy of oral UFT plus leucovorin therapy for colon cancer with ovarian and multiple liver metastases: report of two cases.

Case 1: a patient was diagnosed as having ascending colon cancer with right ovarian metastasis, and underwent palliative right hemicolectomy plus oophorectomy. The tumor was a well-differentiated adenocarcinoma with right ovarian metastasis, and the disease was classified as stage IV. Oral chemotherapy with UFT plus LV was performed for about 3 years, and the patient is still being followed up with no recurrence at 5 years postoperatively. Case 2: a patient was diagnosed as having incomplete large bowel obstruction caused by ascending colon cancer, and underwent curative right hemicolectomy. The tumor was a moderately differentiated adenocarcinoma, and the disease was classified as stage II. Since multiple liver metastases developed at 3 months postoperatively, oral chemotherapy with UFT plus LV was started. Imaging studies showed the complete elimination of liver metastases after 2 months. Subsequently, liver metastasis recurred about 10 months later. The patient died of unrelated cerebral infarction at 2 years and 6 months postoperatively.

Adenocarcinoma↗

PubMedDate not supplied

Rheumatoid arthritis associated with methotrexate-induced pneumonitis: improvement with i.v. cyclophosphamide therapy.

Pneumonitis is one of the most serious adverse effects associated with low-dose weekly methotrexate (MTX) therapy. Immediate cessation of MTX, and the introduction of oxygen therapy and glucocorticoids usually results in a dramatic improvement in the pulmonary toxicity. We report here a case of MTX-induced pneumonitis in a patient with rheumatoid arthritis (RA). Severe hypoxemia and interstitial infiltration in both lung fields did not respond to the withdrawal of MTX and the administration of oxygen and steroid pulse therapy. When intravenous cyclophosphamide (CYC) pulse therapy was initiated, however, rapid physiologic and radiographic improvement was seen. Our case suggests that CYC treatment may have a beneficial effect on MTX-induced pneumonitis that is resistant to steroid therapy.

Aged↗