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Biomedical subjects

S Morimoto

Publications and source records attributed to S Morimoto.

At least 433 records · Page 24Linked to original sources
PubMed1990

The influence of delivery mode on biological inactive renin level in umbilical cord blood.

In order to investigate the influence of delivery mode on biological inactive renin levels in fetal circulation, plasma inactive renin (PIR), plasma renin activity (PRA) and plasma total renin (PTR) were measured in umbilical venous blood samples of 21 infants delivered vaginally after spontaneous labor and of 9 infants delivered by elective cesarean section after the onset of labor. Biological renin activities were measured by bioassay. The PIR levels in infants delivered vaginally were significantly lower than those in infants delivered by cesarean section, while the PRA levels were the opposite. However, the PTR levels were not significantly different between the two groups. These results suggest that the plasma levels of biological inactive renin in infants delivered vaginally may decrease, probably due to its conversion to active renin in the second stage of labor.

Adult↗
PubMed1990

Effects of prostaglandin F2 alpha on the mobilization of cytosolic free calcium in vascular smooth muscle cells and on the tension of aortic strips from rats.

The possible mechanism of action of prostaglandin F2 alpha on vascular smooth muscle was investigated. Prostaglandin F2 alpha induced sustained tonic vasoconstriction of rat aortic strips, accompanied by rapid increase in the cytosolic free Ca2+ concentration [( Ca2+]i) in the vascular smooth muscle cells. Prostaglandin F2 alpha also evoked rapid increase in production of inositol 1,4,5,-trisphosphate (Ins-P3). Moreover, it increased release of Ca2+ from nonmitochondrial pools in digitonin-permeabilized vascular smooth muscle cells, although this effect was much weaker than that of Ins-P3. These results suggest that the sustained action of prostaglandin F2 alpha may involve not only a rise in [Ca2+]i mediated by Ins-P3, but also a direct stimulation of Ca2+ from intracellular stores.

Animals↗
PubMed1990

Bone marrow transplantation in canine GM1 gangliosidosis.

Allogeneic bone marrow transplantation was carried out in an 81-day-old Portuguese water dog with GM1 gangliosidosis using a DLA identical sibling as donor. Engraftment was complete and beta-galactosidase activity in leukocytes of the transplanted dog were similar to those in the donor. Over the next 2.5 months neurological deterioration in the transplanted dog was similar to that in untreated dogs with GM1 gangliosidosis. Cerebral ganglioside GM1 concentrations were not diminished by bone marrow transplantation and cerebral beta-galactosidase activity was negligible. We conclude that allogeneic bone marrow transplantation early in life is ineffective in canine GM1 gangliosidosis.

Animals↗
PubMed1990

MR imaging of primary pulmonary lymphoma.

We present a patient with primary pulmonary lymphoma studied by magnetic resonance (MR), whose MR appearance was considered to be suggestive of the disorder. On T1-weighted MR images the tumour was seen as a large mass with homogeneous signal intensity, replacing the entire left lower lobe, while on T2-weighted images it was demonstrated as a homogeneous mass with a surrounding thin layer of greater signal intensity. This discrimination was not possible with computed tomography.

Aged↗
PubMed1990

Expression of histocompatibility antigen HLA-DR on the epithelial cells of the pancreatic duct and thyroid follicle. An autopsy case.

An autopsy case of chronic pancreatitis associated with unusual chronic thyroiditis in a 54-year-old woman is presented. Microscopically, the pancreas was densely infiltrated by lymphocytes and its exocrine parenchyma was completely replaced by sclerotic tissue. The thyroid gland was also infiltrated by lymphocytes, but no lymphoid follicles were observed. These morphological changes are rare findings with respect to the severity of inflammation and the association of the affected organs. Further findings suggested involvement of an autoimmune mechanism in the pathogenesis of these lesions. Using the avidin-biotin-conjugate technique and antibodies (Abs) against T lymphocyte and HLA-DR antigens (Ags), immunological aspects of the lesions were studied. Most of these infiltrating lymphocytes were revealed to be T lymphocytes, and HLA-DR Ags were observed on the epithelial cells of the pancreatic ducts and thyroid follicles. As a control, 45 surgical specimens of pancreas and thyroid gland were studied for detection of HLA-DR expression on the epithelial cells. One case of chronic pancreatitis was revealed to express HLA-DR Ag on the epithelium. The patient was a 44-year-old woman who had silently developed pancreatic cyst due to chronic inflammation. This finding also suggests a role of autoimmunity in the pathogenesis of chronic idiopathic pancreatitis.

Autopsy↗
PubMed1990

Saposins (sphingolipid activator proteins) in the twitcher mutant mouse.

The twitcher mutant mouse, the animal model of Krabbe disease (human globoid cell leukodystrophy), is characterized by apparent deficiency of galactosylceramide beta-galactosidase activity. Saposin A and C, the heat-stable small sphingolipid activator glycoproteins, stimulate the activity of galactosylceramide beta-galactosidase as well as glucosylceramide beta-glucoside. The role of these saposins in the twitcher mutation was investigated. Boiled supernatant fractions, which contained saposins, were prepared from homogenates of twitcher brain, liver, kidney, and spleen. These preparations showed an almost identical effect on the activity of purified glucosylceramide beta-glucosidase (measured by hydrolysis of 4-methylumbelliferyl-beta-glucoside) with similar preparations from control tissues. The effect on the activity of galactosylceramide beta-galactosidase as well as 4-methylumbelliferyl-beta-glucoside beta-glucosidase in the twitcher brain and liver homogenates by authentic saposin A and C was similar to that in control tissues. These results suggest that the twitcher mutation does not affect the concentrations of saposin A or C or their interaction with galactosylceramide beta-galactosidase.

Animals↗
PubMed1990

Comparison of the production of cyclic AMP in response to parathyroid hormone in fibroblasts from aged subjects and young subjects: lack of an age-dependent decrease.

An age-dependent effect on the ability to produce cyclic AMP in response to parathyroid hormone (PTH) stimulation was examined using culture skin fibroblasts from both young and elderly female subjects. The mean values of both absolute and comparative production of intracellular cyclic AMP due to various concentrations of PTH administration did not differ between the two age groups, although the mean serum PTH level was significantly higher in the elderly subjects. These results indicate that the decreased response of the target organ to PTH in aged subjects can be explained mainly by the decreased number of intact cells rather than a decreased response of individual cells to PTH.

Adolescent↗
PubMed1990

Possible participation of calcium-regulating factors in senile dementia in elderly female subjects.

um-related factors were compared in 60 elderly female subjects, who were classified into three groups as nondementia group (n = 18), groups of senile dementia of Alzheimer type (SDAT, n = 22) and of vascular type (VTD, n = 20). The group of SDAT showed significant decrease in serum calcium, and increases in serum parathyroid hormone and urinary Ca, and tendency of decrease in serum 1,25-dihydroxyvitamin D, compared to those of the nondementia group. However, the group of VTD, without showing these features, showed a tendency towards decreased serum calcitonin. These results suggest that Ca and Ca-regulating hormones may play several important and different roles in senile dementia.

Aged↗
PubMed1990

Left ventricular ejection performance, wall stress, and contractile state in aortic regurgitation before and after aortic valve replacement.

Left ventricular ejection performance, wall stress, and contractile state were evaluated in 35 patients with chronic aortic regurgitation. Cineangiography and pressure measurements were obtained before and a mean of 26 months after aortic valve replacement, and data were compared with those from 30 normal control subjects. The relation between quantitative changes in wall stress and changes in ejection fraction after surgery was determined. Preoperatively, end-systolic stress was elevated in patients with aortic regurgitation (218 +/- 45 vs. 160 +/- 23 kdynes/cm2 [mean +/- SD] for control subjects, p less than 0.01), and ejection fraction was depressed (0.46 +/- 0.11 vs. 0.65 +/- 0.05, p less than 0.01). End-systolic stress decreased postoperatively (151 +/- 41 kdynes/cm2, p less than 0.01) and ejection fraction increased (0.58 +/- 0.11, p less than 0.01). The magnitude of increase in ejection fraction correlated significantly and negatively (r = -0.65) with the quantitative change in end-systolic stress after surgery. Contractile function, as assessed by the ejection phase index-end-systolic stress relation, did not significantly change: 23 of 35 patients preoperatively and 18 of 35 patients postoperatively had values that clearly fell below the 95% confidence limit of the ejection fraction-end-systolic stress relation for controls. After surgery, individual ejection fraction-end-systolic stress relationships demonstrated a shift parallel to the regression curve for the control subjects. Moreover, persistent postoperative left ventricular hypertrophy was significantly associated with persistent contractile dysfunction. Thus, late improvement in left ventricular ejection performance after aortic valve replacement can be attributed to the reduction in end-systolic stress. Contractile function itself was not improved by surgery. Persistent postoperative hypertrophy may be a marker for myocardial contractile dysfunction.

Adolescent↗
PubMed1990

Restenosis after percutaneous transluminal coronary angioplasty--a histopathological study using autopsied hearts.

Restenosis was studied histopathologically by serial step sectioning of 22 coronary arteries from 21 patients in whom percutaneous transluminal coronary angioplasty (PTCA) had been performed (9 arteries from patients who had died shortly after PTCA and 13 from those who had died considerably later). Nine of the 13 arteries from the patients who had died long after PTCA were immunohistochemically stained using anti-actin antibody for examination of spindle-shaped cells proliferating in the intima. In the patients who had died shortly after PTCA, all 9 arteries showed fresh thrombus formation. In the patients who had died considerably later after PTCA, however, there was fragmentation of the internal elastic lamina (IEL) in 9 arteries. In each of these 9 arteries, a remarkable proliferation of intimal cells was observed on the intimal side, mainly at the site of the IEL fragmentation. These spindle-shaped cells were identified as smooth muscle cells (SMC) because they stained reddish-brown with Masson's trichrome, and because immunohistochemical staining with anti-actin antibody was also positive. In 2 arteries, proliferation of SMC and elastic fibers was observed on the luminal side of the intima, despite absence of fragmentation in the IEL. Proliferation of SMC in false lumens was identified in 2 patients with medial dissection. From the above findings, the following 4 forms of restenosis after PTCA have been identified: 1. thrombus formation; 2. proliferation of SMC on the intimal side, mainly around fragmentation in the IEL; 3. proliferation of SMC on the luminal side of the intima where there was no fragmentation of the IEL; and 4. proliferation of SMC in dissected false lumen. The proliferation of SMC on the intimal side of the disrupted IEL was thought to have been a result of migration of SMC from the media to the intima, because SMC proliferation was seen around the disrupted region.

Adult↗
PubMed1990

Inhibitory effects of nisoldipine and saralasin on angiotensin II-induced antidiuresis in anesthetized dogs.

Inhibitory effects of the calcium channel blocker nisoldipine on angiotensin II-induced antidiuresis were investigated in anesthetized dogs, and the findings were compared with those of saralasin. Intrarenal arterial infusion of 10 ng/kg/min angiotensin II resulted in marked decreases in renal blood flow (RBF) and urine formation, with a relatively moderate decrease in glomerular filtration rate. There were marked reductions in the fractional excretion of lithium, which is used as an index of the fractional proximal excretion of sodium, and the fractional distal excretion of sodium. Nisoldipine (50 ng/kg/min) administered intrarenally produced a partial inhibition on the decreased response of RBF to angiotensin II. The peptide-induced decreases in urine flow, urinary excretion of electrolytes and fractional excretion of electrolytes were abolished by nisoldipine. In contrast, when saralasin was administered intrarenally at 10 ng/kg/min, a dose which could partially inhibit the angiotensin II-induced decrease in RBF to the same extent as seen with nisoldipine, the antagonist attenuated, but did not abolish, the antidiuretic action of angiotensin II. Significant decreases in urine formation by angiotensin II were observed, even in the presence of saralasin. These results suggest that nisoldipine, unlike saralasin, preferentially interferes with the stimulatory effect of angiotensin II, as related to the renal tubular reabsorption of sodium and water.

Anesthesia↗
PubMed1990

Diuretic effects of L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) in anesthetized rats.

A synthetic amino acid, L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS), can be converted to (-)-norepinephrine (NE) by aromatic L-amino acid decarboxylase (AADC) in various mammalian tissues. Recent studies have indicated the pressor and diuretic effects of L-threo-DOPS. In this study, we examined the effects of L-threo-DOPS on renal hemodynamics and function in anesthetized rats, and evaluated possible mechanisms of the diuresis. Intravenous infusion of L-threo-DOPS at 120 micrograms/kg/min exerted a significant increase in mean arterial pressure (MAP). There was a slight but nonsignificant decrease in renal blood flow (RBF). Although the glomerular filtration rate (GFR) remained at a constant level, urine flow (UF) and urinary sodium excretion (UNaV) increased significantly during the drug infusion. Pretreatment with AADC inhibitor, benserazide, completely blocked both the pressor and diuretic effects of L-threo-DOPS. When the renal perfusion pressure was protected from the pressor effect of the drug by using a Blalock clamp, the drug-induced diuresis was abolished. The diuretic effect of L-threo-DOPS was markedly attenuated by the administration of phentolamine. There was a positive correlation between plasma NE concentration and UF during the infusion of L-threo-DOPS. Intrarenal arterial infusion of L-threo-DOPS at 20 micrograms/kg/min was without effect on renal function. These results indicate that diuresis and natriuresis induced by L-threo-DOPS are dependent on the pressor effect of NE via peripheral alpha-adrenoceptor activation.

Anesthesia↗
PubMed1990

CT evaluation of anaplastic thyroid carcinoma.

CT findings in 19 patients with anaplastic thyroid carcinoma were compared retrospectively with pathologic findings and the results of palpation. The carcinoma appeared as a large mass of low attenuation accompanied by dense calcification in 58% of the patients; there was necrosis in 74%. Often, adjacent structures were infiltrated. CT correctly showed tumor invasion of the carotid artery (7/7), internal jugular vein (9/10), larynx (5/6), trachea (8/10), esophagus (4/5), mediastinum (5/5), and regional lymph nodes (14/16). Seven patients (50%) had necrotic nodes. CT was superior to palpation in the detection of a primary tumor in one patient and of metastatic nodes in seven patients. It suggested a suitable place for biopsy in two patients, leading to a correct diagnosis. CT altered surgical planning in five patients with intrathoracic extension of the thyroid tumor, and in three patients with laryngeal or esophageal invasion of the tumor. CT can increase diagnostic accuracy in patients with anaplastic thyroid carcinoma by suggesting a likely diagnosis and by indicating an appropriate site for biopsy. It is indispensable in the planning of surgery for patients with this disorder.

Adult↗
PubMed1990

Percutaneous biopsy of thoracic lesions: value of sonography for needle guidance.

Fluoroscopy and CT are widely used to guide percutaneous needle biopsy of thoracic lesions. However, some lesions are not sufficiently visible on fluoroscopy and others are dangerous to access on CT without real-time monitoring. When these are the circumstances, sonographic guidance may be helpful. Real-time sonography was used to guide percutaneous needle biopsy in 124 patients with thoracic lesions. The indications for sonographic guidance included pulmonary, pleural, or mediastinal lesions in contact with the chest wall, including lesions near the heart or great vessels (n = 12); lesions in the apical region (n = 5); lesions in a juxtadiaphragmatic location (n = 6); small lung nodules adjacent to the chest wall (n = 16); and peripheral tumors with adjacent pleural effusion (n = 4). A diagnosis was made in 74 (90%) of 82 malignant lesions and in 24 (67%) of 36 benign lesions. Complications included pneumothorax (n = 5), hemoptysis (n = 1), and hemothorax (n = 1). The advantages of sonographic guidance are that the sonographic equipment is mobile and real-time monitoring makes the procedure safer. Its limitations are that it cannot be used when aerated lung or free air (pneumothorax) lies between the chest wall and the lesion and that cavitary lesions are difficult to sample by biopsy. Our results show that the use of sonographic guidance considerably expands the number of thoracic lesions amenable to percutaneous biopsy.

Biopsy, Needle↗
PubMed1990

Chemical modification of erythromycins. II. Synthesis and antibacterial activity of O-alkyl derivatives of erythromycin A.

A series of O-alkyl erythromycin A derivatives have been synthesized and their antibacterial activities compared with those of erythromycin A (1) and 6-O-methylerythromycin A (3). Methylation of the hydroxyl groups of erythromycin A analogue proceeded stepwise by the two main pathways beginning at the C-6 and C-11 positions, individually. O-Alkylation, other than methylation, took place at the C-11 hydroxyl group exclusively. Among O-alkyl derivatives, 6,12-di-O-methylerythromycin A (5) showed comparable in vitro antibacterial activity to those of 1 and 3. 11-O-Methylerythromycin A (8) was slightly less active than 1. O-Methylation at the C-4" position resulted in a decrease of antibacterial activity.

Animals↗
PubMed1990

Chemical modification of erythromycins. III. In vitro and in vivo antibacterial activities of new semisynthetic 6-O-methylerythromycins A, TE-031 (clarithromycin) and TE-032.

The in vitro and in vivo antibacterial activities of 6-O-methylerythromycin A (TE-031, A-56268, or clarithromycin) and 6,11-di-O-methylerythromycin A (TE-032) have been compared with those of erythromycin A (EM) and josamycin (JM). TE-031 and TE-032, having the same antibacterial spectra as EM, are active against aerobic Gram-positive bacteria, some Gram-negative bacteria, anaerobic bacteria, L-form bacteria and Mycoplasma pneumoniae. The activity of TE-031 against clinical isolates is equal to or two times more potent than that of EM, whereas TE-032 is slightly less active than EM. The activities of TE-031 and TE-032 are pH dependent (more active at pH 8 than at 5) and are increased by adding serum to medium. TE-031 and TE-032 show dose-related bactericidal activities against Haemophilus influenzae. The therapeutic efficacies of TE-031 and TE-032 against systemic and subcutaneous infections provoked by Gram-positive bacteria in mice are 4- to 35-fold superior to those of EM and JM. TE-031 and TE-032 have demonstrated higher and longer-lasting plasma levels than EM when administered orally to mice, rats or dogs.

Animals↗