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Biomedical subjects

S Morimoto

Publications and source records attributed to S Morimoto.

At least 253 records · Page 14Linked to original sources
PubMed1995

Enhancement of norepinephrine and angiotensin II-induced renal effects by NG-nitro-L-arginine, a nitric oxide synthase inhibitor.

We investigated whether endogenous nitric oxide (NO) has a role as an inhibitory modulator of norepinephrine (NE)- and angiotensin II (Ang II)-induced renal effects in anesthetized dogs. Intrarenal arterial infusion of NE (100 ng/kg/min) or Ang II (10 ng/kg/min) decreased renal blood flow (RBF), glomerular filtration rate (GFR) and urine formation. The NE- or Ang II-induced renal effects were augmented by the intrarenal administration of a NO synthase inhibitor, NG-nitro-L-arginine (NOARG), at doses (10 and 40 micrograms/kg/min) which did not affect the mean arterial blood pressure and heart rate. The stimulating activity of NOARG on NE- or Ang II-induced renal effects were abolished by the simultaneous administration of L-arginine, a NO precursor. These findings suggest that endogenous NO, which is probably generated within the kidney, functions as an inhibitory modulator in NE- or Ang II-induced renal vasoconstriction and antidiuresis.

Amino Acid Oxidoreductases↗
PubMed1995

Pulmonary arteriovenous fistula associated with unequal branching of the pulmonary artery system.

A 60-year-old woman was admitted to our hospital with shortness of breath and was diagnosed to have pulmonary arteriovenous fistula with unequal branching of the pulmonary artery system, as assessed by pulmonary angiography. The concomitant occurrence has not been reported previously. Although the etiology of these abnormalities is unknown, these abnormalities are considered to have occurred during an early stage of fetal development. The analysis of a concomitant occurrence of these abnormalities may be useful in elucidating the etiology of pulmonary arteriovenous fistula.

Arteriovenous Fistula↗
PubMed1995

Non-obese Cushing's syndrome in an aged woman with non-insulin-dependent diabetes mellitus.

A 76-year-old diabetic woman with non-obese Cushing's syndrome developed poor glycemic control with glibenclamide. She presented with a slight weight loss while bedridden due to a fall. Cushing's syndrome in this patient was suspected because of hypercortisolemia with eosinopenia, and adrenal Cushing's syndrome was diagnosed by endocrine and radiological examinations. A right adrenal adenoma was confirmed by autopsy. In this patient, progressive obesity and other common features of Cushing's syndrome may have been concealed by aging itself and coexisting diabetes mellitus.

Age Factors↗
PubMed1995

Isotonic mannitol and the prevention of local heat generation and tissue adherence to bipolar diathermy forceps tips during electrical coagulation. Technical note.

The authors observed temperature levels of saline and mannitol on the tips of bipolar diathermy forceps during application of power to the forceps and compared the effects of irrigation with saline and isotonic mannitol on electrical coagulation of vessels during neurosurgical operations. There was a marked rise in the temperature of saline corresponding to increased output power of the coagulator; there was no rise in the temperature of the mannitol. Irrigation with isotonic mannitol during surgery resulted in a considerable reduction of adherence of burned tissue and blood clots to forceps tips during coagulation of both arteries and veins compared with that which occurred during irrigation with saline. These results demonstrate that irrigation with an isotonic mannitol surpasses that with conventional ionic fluids, such as a saline, for prevention of both tissue adherence to bipolar diathermy forceps and removal of heat generated during electrical coagulation.

Burns↗
PubMed1995

A novel bioactive delta lactone FD-211. Taxonomy, isolation and characterization.

During our screening program for natural product drugs effective against multidrug-resistant mammalian cells, we have discovered a new delta lactone FD-211 from the fermantation broth of Myceliophthora lutea TF-0409. FD-211 had a broad spectrum activity against cultured tumor cell lines, including adriamycin-resistant HL-60 cells.

Animals↗
PubMed1995

Bassiatin, a new platelet aggregation inhibitor produced by Beauveria bassiana K-717.

A new platelet aggregation inhibitor, bassiatin, was isolated from the cultured broth of Beauveria bassiana which had been isolated from a soil sample collected in Yunnan province, China. The structure of bassiatin was determined to be (3S, 6R)-4-methyl-6-(1-methylethyl)-3-phenylmethyl-1, 4-perhydrooxazine-2,5-dione by NMR analysis, X-ray crystallographic analysis and chemical synthesis. Bassiatin inhibited ADP-induced aggregation of rabbit platelets with the IC50 being 1.9 x 10(-4) M.

Animals↗
PubMed1995

Role of transforming growth factor-beta 1 on platelet-induced enhancement of endothelin-1 production in cultured vascular endothelial cells.

We and other investigators obtained evidence that platelets stimulate endothelin-1 (ET-1) production at both message and protein levels in vascular endothelial cells (ECs), and that platelet-derived transforming growth factor-beta 1 (TGF-beta 1) is responsible for this stimulation. In the present study, we examined the effects of acidification or heat treatment, known to activate latent TGF-beta 1, on the platelet supernatant-induced ET-1 production in cultured porcine aortic ECs. Supernatant of platelets (6.0 x 10(8) platelets/ml) aggregated by adenosine diphosphate contained large amounts of TGF-beta 1, but were almost in a latent form, and the proportion of active TGF-beta 1 in the supernatant was increased markedly in the case of acidification or heat treatment. These treatments also significantly potentiated the supernatant-induced stimulation of prepro ET-1 mRNA expression and the ET-1 release in ECs. Purified TGF-beta 1 also enhanced ET-1 release, dose-dependently, but the enhancement declined at the higher concentrations. Thus, powerful stimulation of ET-1 production by platelet supernatant after acidification or heat treatment cannot be explained only by increments in active TGF-beta 1. The supernatant-induced stimulation of ET-1 synthesis was significantly inhibited by concomitant treatment of TGF-beta 1 neutralizing antibody, but this inhibition was incomplete even at a concentration that abolished TGF-beta 1-induced maximal stimulation. These results suggest that platelet-induced stimulation and subsequent acidification and heat treatment-induced potentiation on endothelial ET-1 production depend closely on release and activation of TGF-beta 1 derived from platelets.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Role of parathyroid hormone-related protein in the proliferation of vascular smooth muscle cells.

Human parathyroid hormone-related protein(1-34) [hPTHrP(1-34)] inhibited [3H]thymidine incorporation into DNA of cultured vascular smooth muscle cells (VSMC) and increased intracellular cAMP accumulation, both in a concentration-dependent manner. The potency of hPTHrP(1-34) was similar to that of human parathyroid hormone(1-34) [hPTH(1-34)], but their antagonists, hPTHrP(7-34) and hPTH(3-34), showed no effect on VSMC DNA synthesis. The inhibitory effect of PTHrP on VSMC DNA synthesis was mimicked by dibutyryl-cAMP but not by dibutyryl-cGMP. These results suggest that PTHrP, as an autocrine and/or paracrine regulator, may inhibit VSMC DNA synthesis mediated at least partly by cAMP, a second messenger which has also been proposed to mediate vascular relaxation.

Animals↗
PubMed1995

The identity of proliferating cells in bone tumors with cartilaginous components: evaluation by double-immunohistochemical staining using proliferating cell nuclear antigen and S-100 protein.

S-100 protein (S-100) appears to be a marker for bone tumors of cartilaginous origin. Any analyses of proliferative activity in S-100-positive tumor cells, however, has not yet been presented. This study assessed the proliferative activity of those cells by means of a double-immunohistochemical staining method using proliferating cell nuclear antigen (PCNA) and S-100. The most intense reactivity for S-100 was found in the well-differentiated chondrocytes of enchondromas, osteochondromas, and osteosarcomas. On the contrary, the more immature the tumor cells were, the more intensely positive they were for PCNA. In parosteal chondrosarcoma, exceptionally, PCNA-positive as well as S-100-positive cells were abundant, suggesting that these proliferating cells produced S-100. In periosteal osteosarcoma, however, the proliferating cells labeled by PCNA revealed little reactivity for S-100. This immunohistochemical method is potentially useful to know the identity and origin of proliferating cells and may sometimes be diagnostic for bone tumors containing cartilaginous elements.

Adolescent↗
PubMed1995

The efficacy of indomethacin in the treatment of uremic pericarditis.

Uremic pericarditis is common in patients undergoing chronic hemodialysis and has been difficult to cure using conservative medical and surgical methods of treatment. Indomethacin therapy for uremic pericarditis has been reported infrequently. We present a case of uremic pericarditis in which indomethacin was particularly effective. The patient was a 45-year-old woman with thrombocytopenia due to Banti's syndrome and congestive heart failure with pericardial effusion. She had been undergoing hemodialysis for 3 years for chronic renal failure due to chronic glomerulonephritis. Uremic pericarditis was diagnosed based on serological laboratory results, aspirated pericardial fluid, and an echocardiogram. She was treated with oral doses of 25 mg t.i.d. indomethacin in addition to hemodialysis and extracorporeal ultrafiltration method. Pericardial effusion and left ventricular dysfunction disappeared after indomethacin therapy for 38 days. There are conflicting reports on the efficacy of indomethacin therapy in patients with uremic pericarditis. While indomethacin therapy was very effective in our case, there may be many causes of uremic pericarditis for which indomethacin may not be efficacious. Further investigations of indomethacin therapy for patients with uremic pericarditis are necessary to elucidate the therapeutic mechanism by which indomethacin acts.

Administration, Oral↗
PubMed1995

[Clinical study on antimicrobial prophylaxis following extracorporeal shock wave lithotripsy].

One hundred and sixty one patients with upper urinary stones were examined for antimicrobial prophylaxis following extracorporeal shock wave lithotripsy (ESWL). They were divided into two groups, the low-risk group (n = 133) and high-risk group (n = 28), according to the risk factors of urinary tract infection. The patients in the low-risk group were further randomized into two groups which were orally given ofloxacin for 7 days after ESWL (Group A, n = 66), no antimicrobial (Group B, n = 67). The patients in the high-risk group were randomly subdivided into three groups which were given flomoxef intravenously for 2 or 3 days and ofloxacin for 4 or 5 days thereafter (Group C, n = 10), flomoxef only for 2 or 3 days and no drugs later (Group D, n = 10), ofloxacin for 7 days (Group E, n = 8). In all of the patients in the low-risk group, during the 7 days after ESWL, fever elevation was observed in only 1.5% of patients, and bacteriuria in 10.0% on the 7th day. There was no difference in frequency of fever elevation and bacteriuria following ESWL between Group A and Group B. These findings indicate that prophylactic antimicrobial after ESWL treatment is not necessary for low risk patients with urinary tract infections. In the high-risk group, the over-all rates of fever elevation and bacteriuria were 21.4% and 24.0% respectively. The difference of effectiveness among the prophylactic regimens of the three groups (Group C, D, E) was not shown.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[A case of hypertensive hypertrophy in which both regression of hypertrophy and improvement of the abnormalities in iodine-123-metaiodobenzylguanidine (MIBG) myocardial imagings were observed after antihypertensive therapy].

A case of hypertensive hypertrophy is described in which both regression of hypertrophy and improvement of the abnormalities in iodine-123-metaiodobenzylguanidine (MIBG) myocardial imagings were seen after 7 months of antihypertensive therapy. A 58-year-old man was diagnosed as having essential hypertension and hypertensive hypertrophy. The patient was treated with antihypertensive drugs and showed regression of left ventricular hypertrophy on electrocardiograms and echocardiograms. MIBG observations made before and after antihypertensive therapy showed increased heart-to-mediastinum activity ratio and decreased cardiac washout ratio. Despite the many theories addressing the mechanisms of regression of left ventricular hypertrophy, the process is still unclear. In the present case, the improvement of cardiac sympathetic nervous dysfunction might have been related to the regression of left ventricular hypertrophy because the abnormality in MIBG images improved. MIBG, therefore, may be helpful in clarifying the mechanisms of the regression of hypertensive hypertrophy.

3-Iodobenzylguanidine↗
PubMed1995

Involvement of endothelin-1 in deoxycorticosterone acetate-salt-induced hypertension and cardiovascular hypertrophy.

The role of endothelin-1 (ET-1) in the development and maintenance of hypertension is controversial. To determine the role of ET-1, we investigated the possible involvement of ET-1 in the pathogenesis of experimental hypertensive rats. In deoxycorticosterone acetate (DOCA)-salt hypertensive rats, a significant increase in aortic immunoreactive ET (IR-ET) level was observed, compared with age-matched sham-operated rats. Intravenous injection of the ETA receptor antagonist FR139317 (10 mg/kg) produced a slight decrease in blood pressure in sham rats. In the DOCA-salt hypertensive rats, FR139317 had a more pronounced hypotensive effect. Treatment with the antagonist in nitro-L-arginine (LNA)-induced hypertensive rats, two-kidney, one-clip (2K1C) renal hypertensive rats, spontaneously hypertensive rats (SHR), and stroke-prone SHR (SHR-SP) produced only moderate hypotensive effects, of the same degree as those in normotensive rats. Long-term treatment with FR139317 in DOCA-salt hypertensive rats efficiently suppressed the development of hypertension and cardiovascular hypertrophy. We propose that ET-1 production in vascular tissues is increased in DOCA-salt hypertensive rats. In addition, our study suggests the pathophysiologic importance of ET-1 and the ETA receptor in DOCA-salt-induced hypertension but not in SHR, in SHR-SP, in 2K1C renal hypertension, and in LNA-induced hypertension.

Animals↗
PubMed1995

Non-machinery-based system for cell-free, concentrated autogenous ascitic fluid reinfusion.

A non-machinery-based system for the reinfusion of ascitic fluid was developed and assessed. In fundamental studies utilizing bovine serum, this procedure proved economical, quick and useful. The most suitable filter was PS-R (#405-2). Bovine serum with a protein concentration below 3.0 g/dl was treated using this system. Samples containing blood (prepared to 0.5% hematocrit) were also treated, but the treatment time required was double that of serum with the same protein concentration. In both cases the protein recovery ratios were about 90%. We conducted clinical studies on 62 occasions (machinery-based system; 31 times, non-machinery-based system; 31 times) on 19 cases of ascites refractory to treatment with various drugs including diuretics. Clarification of the differences between the non-machinery-based system, indicated the former to be superior. This new procedure is easier because of its use of no machinery, and the high protein recovery ratio proved its usefulness.

Adult↗
PubMed1995

[Motor reorganization in the motor cortex].

Plasticity within the human central motor system has been studied with transcranical magnetic stimulation in patients with peripheral and central nervous diseases. In 4 patients with a complete upper limb palsy due to traumatic cervical root avulsion, surgical anastomosis of intercostal to musculocutaneous nerves was performed to restore function in the biceps brachii muscle. The motor unit discharges became independent from respirations gradually over 1 to 2 years. Motor cortex mapping of the reinnervated biceps muscle showed a gradual change over 4 to 33 months from the area of the intercostal muscles to that of the arm area, which was more lateral on the motor cortex. These findings suggest that reorganization of the motor cortex to arm flexor muscles occurs following peripheral nerve anastomosis. In 8 patients with chronic cerebral infarction with hemiplegia. Four of 8 patients did not show MEPs in paralytic hand muscles by contralateral cortex stimulation, but showed small MEPs by ipsilateral cortex stimulation. These cases had the huge cortical infarction unilaterally in CT. Another four of 8 patients showed small MEPs in paralytic hand muscles by contralateral cortex stimulation, but no MEPs by ipsilateral cortex stimulation. These cases had the subcortical infarction unilaterally in CT. These findings suggest that reorganization of motor cortex following unilateral cerebral infarction.

Anastomosis, Surgical↗
PubMed1994

Ca2+ binding to cardiac troponin C in the myofilament lattice and its relation to the myofibrillar ATPase activity.

The Ca(2+)-binding properties of troponin C in the intact myofilament lattice and their relation to the activation of ATPase were investigated with isolated porcine cardiac myofibrils. Ca2+ binding, which is composed of two classes of binding sites with different affinities (classes 1 and 2), was clearly detected by a novel method for subtracting the large background activity of myofibrillar Ca2+ binding. The classes 1 and 2 were equivalent stoichiometrically to the two high-affinity sites (sites III and IV) and a single low-affinity site (site II) of troponin C. In the presence of ATP, positive cooperativity was observed in the Ca2+ binding of class-2 sites and the Hill equation parameters were in excellent agreement with those for the Ca(2+)-activated myofibrillar ATPase activity, which indicated that the activation of ATPase is a linear function of the Ca2+ occupancy of site II. In the absence of ATP, a marked increase in the affinity of only class-2 sites was observed while the cooperativity was lost. These results provide direct evidence that some feedback mechanism exists between myosin crossbridge attachment and the Ca2+ binding to site II of troponin C, which may thus confer positive cooperativity on the Ca2+ activation of myofibrillar ATPase activity.

Actin Cytoskeleton↗
PubMed1994

Elastase enhances cAMP accumulation and the inhibition of DNA synthesis induced by OP-41483, a stable prostacyclin analogue, in vascular smooth muscle cells.

To define the physiological roles of elastase in the vascular wall, we examined whether elastase at low concentrations can modulate the proliferation of vascular smooth muscle cells (VSMC). Elastase itself at low concentrations from 1 to 50 ng/ml inhibited DNA synthesis dose-dependently in VSMC. However, phenylmethylsulfonyl fluoride-inactivated elastase failed to induce this inhibition. OP-41483, a stable analogue of prostacyclin, inhibited DNA synthesis and stimulated accumulation of cAMP in VSMC. Preincubation of VSMC for 24 h with 50 ng/ml elastase enhanced both inhibition of DNA synthesis and the accumulation of cAMP induced by OP-41483. Preincubation of VSMC with 12-O-tetradecanoylphorbol 13-acetate, an activator of protein kinase C (PKC), also enhanced cAMP accumulation induced by OP-41483. On the other hand, elastase failed to enhance OP-41483-induced cAMP accumulation in PKC down-regulated cells. Furthermore, coincubation with chelerythrine, an inhibitor of PKC, inhibited the enhancement of cAMP accumulation induced by preincubation with elastase. These results suggest that elastase at low concentrations can enhance the inhibition of VSMC proliferation induced by prostacyclin through the activation of protein kinase C.

Animals↗