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K Shimamoto

Publications and source records attributed to K Shimamoto.

At least 217 records · Page 12Linked to original sources
PubMed1995

The mechanisms of the renal effects of neutral endopeptidase inhibitor in rats.

To further investigate the mechanisms of renal effects of neutral endopeptidase 24.11 (NEP) inhibition, we employed a specific NEP inhibitor, UK 73967 (UK), with or without a specific kinin receptor antagonist, Hoe 140 (Hoe), or nitric oxide (NO) synthase inhibitor, N-monomethyl-L-arginine (L-NMMA), in Sprague-Dawley rats, and evaluated the urinary NEP, kinins, cGMP and plasma atrial natriuretic peptide (ANP). None of the variables changed with vehicle injection. After injection of UK, NEP decreased significantly and urinary kinins, cGMP, urine volume (UV) and urinary sodium excretion (UNaV) increased significantly. Injected Hoe canceled the increase in UV and UNaV induced by UK. Plasma ANP did not show any difference between vehicle and UK groups. With a pretreatment of L-NMMA, injected UK decreased NEP and increased kinins, while urinary cGMP, UV and UNaV did not increase. In conclusion, augmented kinins may play an important role in the renal water-sodium metabolism by NEP inhibition, and NO may contribute to the kinins' action on this mechanism, while ANP may not contribute to it, at least in normotensive rats. Moreover, changes in urinary cGMP do not reflect the changes in plasma ANP, but rather, those in NO under this condition.

Adrenergic beta-Antagonists↗
PubMed1995

The role of kinins and atrial natriuretic peptide on the renal effects of neutral endopeptidase inhibitor in normotensive and hypertensive rats.

To further elucidate the renal effects of NEP inhibition, we employed NEP inhibitor UK 73967 (UK), with or without a kinin receptor antagonist Hoe 140 (Hoe), in Sprague-Dawley normotensive rats and DOCA-salt hypertensive rats. In Sprague-Dawley rats: 1) injected UK significantly decreased NEP, and increased kinins, urine volume (UV) and urinary sodium excretion (UNaV), while none of the variables changed with vehicle treatment; 2) no difference was found in plasma ANP between the vehicle and UK groups; and 3) Hoe canceled the increases of UV and UNaV caused by UK. In DOCA-salt rats: 1) infused UK significantly decreased NEP, and increased UV and UNaV, while UV and UNaV were slightly decreased, and NEP did not change with vehicle treatment; 2) plasma ANP was significantly higher in UK group than in the vehicle group; and 3) Hoe could not abolish the increase of UV and UNaV induced by UK. These data indicate that the contributions of renal kinins and plasma ANP to the diuretic and natriuretic mechanisms of NEP inhibition may differ between Sprague-Dawley normotensive rats and DOCA-salt hypertensive rats.

Adrenergic beta-Antagonists↗
PubMed1995

The pathophysiological role of renal dopamine and kallikrein in deoxycorticosterone acetate (DOCA)-salt treated rats.

To elucidate the pathophysiological role of the renal dopamine (DA) and kallikrein-kinin systems in volume dependent hypertension under excess mineralocorticoid, the urinary excretions of DA and kallikrein (KAL) were investigated in DOCA-salt treated rats (5 week-old Sprague-Dawley rats, DOCA 100mg pellet, s.c., 1% saline ingestion for 4 weeks, n = 7) for comparison with those of control rats (vehicle, 1% saline ingestion for 4 weeks, n = 10). In vehicle, systolic blood pressure (SBP), urinary excretion of free DA (UDA) and kallikrein (UKAL) did not change through the study. In DOCA treated rats, marked natriuresis was observed with sodium load. SBP and UKAL significantly increased at the 4th week and at the 2nd week, respectively. UDA increased significantly to the peak level at the 1st week, and then decreased gradually. At the 4th week, UDA was significantly lower in DOCA-treated rats than that of vehicle rats. A significant inverse correlation was found between UDA and SBP, and UKAL correlated positively with SBP and urinary excretion of sodium and negatively with UDA in DOCA treated rats. These results suggest that the augmentation of renal dopaminergic activity which may in part cause sodium escape appears at the early stage of DOCA-salt treatment, but this augmentation is subsequently blunted; volume and sodium retention may be associated with the blood pressure elevation at the late stage of DOCA-salt treatment, and that the augmentation of renal kallikrein-kinin system may be a compensatory response to sodium and volume retention in DOCA-salt treated rats.

Animals↗
PubMed1995

[Case-card survey on hypotensive treatment in elderly in three different types of medical facilities].

A case-card survey was carried out to understand trends of hypotensive treatment in elderly in comparison with non-elderly subjects. Data were obtained from 2,897 cases including 1,422 elderly (> or = 65 years old) and 1,475 non-elderly hypertensives (< 65 years old) collected from Sapporo Medical University Hospital and related medical facilities. In the total group of 2,879 cases, frequencies of use of hypotensive drugs were as follows: Ca antagonists, 76.3%, beta-blockers, 31.4%; ACE-inhibitors, 25.1%; diuretics, 18.1; alpha 1-blockers, 10.5%; potassium sparing diuretics, 8.8%. In the elderly group, beta-blockers and ACE-inhibitors were used less frequently than in non-elderly hypertensives. On the contrary, diuretics were administered more frequently in elderly than in non-elderly subjects. Comparing the usage of hypotonics among different types of medical facilities, higher frequencies of use of beta-blockers and diuretics were observed in the university hospital than in general hospitals and private hospitals or clinics. ACE-inhibitors were used less frequently in private facilities than in the university hospital and general hospital. In summary, Ca antagonists were used most frequently in both non-elderly and elderly subjects, and in all three different types of medical facilities. Other hypotonics were used differently according to patients age. There was differences in the usage of drugs apart from Ca antagonists among the three different types of medical facilities.

Adrenergic beta-Antagonists↗
PubMed1995

[A clinical and pathological study of 46 cases of sudden and unexpected death].

A series of 46 autopsied adult cases of sudden and unexpected natural death were investigated. In this study, sudden and unexpected death was defined as any death occurring with 24 hours of onset of symptoms in a person with or without probable cause of death suggested by medical history. The cases included 31 males and 15 females aged 26 to 85 years (mean 66.6 years). Age distribution peaked in seventies. The lesions causing sudden and unexpected death according to the most frequent organ systems were, diseases of the heart (acute myocardial infarction with or without old infarct, 20; old myocardial infarction without acute infarction, 2; dilated cardiomyopathy, 2; sarcoidosis, 1; amyloidosis, 2; and valvular disease, 2), the aorta (ruptured aneurysm, 6; dissecting aneurysm, 2), the respiratory tract (pulmonary embolism, 7; pulmonary hypertension, 1), the alimentary tract (intestinal obstruction, 1), and other diseases (cause unknown, 1). The cardiovascular lesions were found in 78.2% of cases autopsied. The sudden and unexpected death caused by acute myocardial infarction was found in 47.8%, and acute myocardial infarction seemed to play a major role in cardiac sudden death in these series. The respiratory lesions were found in 17.4%. Four of seven cases with pulmonary embolism died in two weeks after surgical operation. The most common underlying disease was post-operative condition.

Adult↗
PubMed1995

[Optimal concentration of contrast medium in helical CT of the thorax].

In 99 examinations of 89 patients, we took CT images of the chest after administering one of three concentrations of contrast medium (iohexol 140 mgI/ml, 240 mgI/ml, 300 mgI/ml) to determine the optimal iodo-concentration for intravenous contrast enhancement in spiral CT. Attenuation values of the superior vena cava, ascending aorta, descending aorta, and pulmonary artery were measured to evaluate the degree of contrast enhancement. Five radiologists judged the image quality by scoring factors such as vascular opacification, delineation of the lung and chest wall, detectability of calcification, lymphadenopathy and pulmonary nodules, and the presence of artifacts. The relationships between the iodo-concentration and the scores were analyzed statistically. The higher the iodo-concentration of the contrast medium administered, the stronger the vascular structures were opacified. There was also a concurrent improvement in the detection of lymphadenopathy. However, artifacts appeared on the administration route as a result of the high-concentration contrast medium, and the image quality was degraded. Among the three groups, iohexol 240 mgI/ml exhibited the best performance, namely, good image quality, so that a high degree of contrast enhancement of the vasculature was obtained with few artifacts due to the contrast medium. However, we believe that iohexol 140 mgI/ml presents no significant problems in routine studies.

Adult↗
PubMed1995

Cardiac sympathetic denervation in transthyretin-related familial amyloidotic polyneuropathy: detection with iodine-123-MIBG.

In familial amyloidotic polyneuropathy (FAP), the peripheral nervous system is predominantly impaired. Cardiac sympathetic function has not been directly assessed. A 65-yr-old man with severe peripheral neuropathy due to primary systemic amyloidosis was studied. Echocardiograms and scintigraphic examinations with 20Tl and 99mTc-pyrophosphate demonstrated highly thickened but normally perfused left ventricular walls with intense diffuse amyloid deposits. No definite myocardial activity of [123I]metaiodobenzylguanidine (MIBG) was detected in any cardiac region, indicating lack of sympathetic nerve endings. Despite maintained cardiac contractility, left ventricular diastolic performance and heart rate variability assessed by power spectral analysis were markedly depressed. Thus, the myocardial defect of MIBG activity may provide direct evidence of impaired cardiac sympathetic nerve endings due to amyloid deposits in FAP.

3-Iodobenzylguanidine↗
PubMed1995

[ST segment re-evaluation immediately after successful recanalization in acute myocardial infarction: predictor for poor recovery of left ventricular regional wall motion].

The value of recanalization therapy in restoring risk area after acute coronary occlusion is well documented. However, some cases show poor recovery of left ventricular function regardless of early reperfusion. This study investigated the use of ST segment re-elevation immediately after recanalization in patients with acute myocardial infarction as a predictor of recovery of regional wall motion and risk area. ST segment change and regional wall motion were compared in 16 patients with [ST(+)] and 8 patients without ST segment re-elevation [ST(-)] after successful recanalization within 6 hours from onset. ST segment re-elevation was defined as 0.2 mV or more in at least two contiguous leads immediately after recanalization. Wall motion was measured from single-plane ventriculograms performed in the acute and chronic (3-4 weeks later) phases in the infarct regions by the centerline method. Hypokinesis was defined as more than -2SD/chord(c) below normal and expressed as SD/c for the severity of regional wall motion and chord number(CN) for risk area. Time from symptom onset to recanalization did not differ between the two groups [3.8 +/- 1.2 hours for ST(-), 3.9 +/- 0.9 hours for ST(+), not significant]. In the ST(-) group, regional wall motion improved from -2.92 +/- 0.33 to -1.45 +/- 0.81 SD/c (p = 0.0005) and risk area decreased from 29.8 +/- 16.6 to 9.5 +/- 15.7 CN (p = 0.005) in the acute and chronic phases, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Intermittent mini-dose vancomycin intravenous administration and closed continuous irrigation technique applied to mediastinitis caused by MRSA following mitral valve replacement].

Mediastinitis caused by MRSA (Methicillin-Resistant Staphylococcus aureus) remains an intractable infection producing high mortality even in these days of advanced chemotherapy. The authors report a case of mediastinitis due to MRSA complicated with acute renal failure following mitral valve replacement. The patient's mediastinum had been thoroughly cleaned with physiological saline solution with 0.2% povidone iodine, and underwent a chemotherapy regimen of mini-dose vancomycin. The patient made favorable progress and recovered completely. Our patient's progress confirmed that when chemotherapy using vancomycin is administered in a patient whose condition is complicated with acute renal failure, closely monitoring the vancomycin serum concentration is essential. Intermittent mini-dose intravenous administration is sufficient to maintain an effective vancomycin serum concentration. In our case, vancomycin serum concentration measured before and at completion of dialysis revealed no appreciable decline.

Acute Kidney Injury↗
PubMed1994

Antihypertensive effects of BQ-123, a selective endothelin ETA receptor antagonist, in spontaneously hypertensive rats treated with DOCA-salt.

We determined the antihypertensive effects of BQ-123 (cyclo(D-Trp-D-Asp-L-Pro-D-Val-L-Leu-), sodium salt), a selective endothelin ETA receptor antagonist, in spontaneously hypertensive rats treated with deoxycorticosterone acetate-salt (DOCA-salt SHR). BQ-123 (1-30 mg/kg/h) decreased blood pressure in DOCA-salt SHR in a dose-dependent manner, although plasma immunoreactive endothelin-1 did not significantly increase and the maximal contractile response to endothelin-1 in the aorta significantly decreased as compared with values observed in age-matched SHR. These results suggest that endogenous endothelin-1 is involved in the maintenance of hypertension in DOCA-salt SHR, and that circulating endothelin-1 is not sufficient to reflect the physiological role of endothelin-1.

Amino Acid Sequence↗
PubMed1994

The promoters of two carboxylases in a C4 plant (maize) direct cell-specific, light-regulated expression in a C3 plant (rice).

C4 plants have two carboxylases which function in photosynthesis. One, phosphoenolpyruvate carboxylase (PEPC) is localized in mesophyll cells, and the other, ribulose bisphosphate carboxylase (RuBPC) is found in bundle sheath cells. In contrast, C3 plants have only one photosynthetic carboxylase, RuBPC, which is localized in mesophyll cells. The expression of PEPC in C3 mesophyll cells is quite low relative to PEPC expression in C4 mesophyll cells. Two chimeric genes have been constructed consisting of the structural gene encoding beta-glucuronidase (GUS) controlled by two promoters from C4 (maize) photosynthetic genes: (i) the PEPC gene (pepc) and (ii) the small subunit of RuBPC (rbcS). These constructs were introduced into a C3 cereal, rice. Both chimeric genes were expressed almost exclusively in mesophyll cells in the leaf blades and leaf sheaths at high levels, and no or very little activity was observed in other cells. The expression of both genes was also regulated by light. These observations indicate that the regulation systems which direct cell-specific and light-inducible expression of pepc and rbcS in C4 plants are also present in C3 plants. Nevertheless, expression of endogenous pepc in C3 plants is very low in C3 mesophyll cells, and the cell specificity of rbcS expression in C3 plants differs from that in C4 plants. Rice nuclear extracts were assayed for DNA-binding protein(s) which interact with a cis-regulatory element in the pepc promoter. Gel-retardation assays indicate that a nuclear protein with similar DNA-binding specificity to a maize nuclear protein is present in rice.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1994

The promoter of the barley aleurone-specific gene encoding a putative 7 kDa lipid transfer protein confers aleurone cell-specific expression in transgenic rice.

This paper describes the aleurone-specific gene Ltp2 from barley, which encodes a putative 7 kDa non-specific lipid transfer protein. As shown by Northern and in situ hybridization analyses, the Ltp2 transcript is present in barley aleurone cells shortly after the initiation of aleurone cell differentiation. The expression of Ltp2 increases until grain mid-maturity, but the mRNA is absent from mature grains. The Ltp2 transcript is undetectable in the embryo and vegetative tissues, confirming the aleurone specificity of the Ltp2 gene. The ability of the isolated 801 bp Ltp2 promoter to direct aleurone-specific expression in immature barley grains is demonstrated by particle bombardment experiments. In these experiments, the activity of the Ltp2 promoter is 5% of the activity of the strong constitutive Actin1 promoter from rice, as quantified by GUS activity measurements. In stably transformed rice plants containing the Ltp2 promoter-Gus construct, the specificity of the Ltp2 promoter is confirmed in vivo by the presence of GUS activity exclusively in the aleurone layer. This study demonstrates the conserved nature of the regulatory signals involved in aleurone-specific gene transcription in cereal grains.

Amino Acid Sequence↗
PubMed1994

Promoter elements required for developmental expression of the maize Adh1 gene in transgenic rice.

To define the regions of the maize alcohol dehydrogenase 1 (Adh1) promoter that confer tissue-specific expression, a series of 5' promoter deletions and substitution mutations were linked to the Escherichia coli beta-glucuronidase A (uidA) reporter gene and introduced into rice plants. A region between -140 and -99 not only conferred anaerobically inducible expression in the roots of transgenic plants but was also required for expression in the root cap, embryo, and in endosperm under aerobic conditions. GC-rich (GC-1, GC-2, and GC-3) or GT-rich (GT-1 and GT-2) sequence motifs in this region were necessary for expression in these tissues, as they were in anaerobic expression. Expression in the root cap under aerobic conditions required all the GC- and GT-rich motifs. The GT-1, GC-1, GC-2, and GC-3 motifs, and to a lesser extent the GT-2 motif, were also required for anaerobic responsiveness in rice roots. All elements except the GC-3 motif were needed for endosperm-specific expression. The GC-2 motif and perhaps the GT-1 motif appeared to be the only elements required for high-level expression in the embryos of rice seeds. Promoter regions important for shoot-, embryo-, and pollen-specific expression were proximal to -99, and nucleotides required for shoot-specific expression occurred between positions -72 and -43. Pollen-specific expression required a sequence element outside the promoter region, between +54 and +106 of the untranslated leader, as well as a silencer element in the promoter between -72 and -43.

Alcohol Dehydrogenase↗
PubMed1994

The rice bZIP transcriptional activator RITA-1 is highly expressed during seed development.

Systematic protein-DNA binding studies have shown that plant basic leucine zipper (bZIP) proteins exhibit a differential binding specificity for ACGT motifs. Here, we show that the rice transcription activator-1 (RITA-1) displays a broad binding specificity for palindromic ACGT elements, being able to bind A-, C-, and G-box but not T-box elements. By using gel mobility shift assays with probes differing in sequences flanking the hexameric core, we identified high-affinity A-, C-, and G-box binding sites. Quantitative and competition DNA binding studies confirmed RITA-1 specificity for these sites. Using rice protoplasts as a transient expression system, we demonstrated that RITA-1 can transactivate reporter genes possessing high-affinity but not low-affinity RITA-1 binding sites. Our results established a direct relationship between in vivo transactivation and in vitro binding activity. Transient expression assays that demonstrated the ability of RITA-1 to transactivate a construct containing rita-1 5' flanking sequences suggest that the factor may be autoregulated. Histochemical analysis of transgenic rice plants showed that a rita-1-beta-glucuronidase transgene is expressed in aleurone and endosperm cells of developing rice seeds. We propose that RITA-1 plays a role in the regulation of rice genes expressed in developing rice seeds.

Amino Acid Sequence↗
PubMed1994

Insulin sensitivity and the effects of insulin on renal sodium handling and pressor systems in essential hypertensive patients.

Insulin resistance and hyperinsulinemia are linked with essential hypertension. To clarify insulin sensitivity in Japanese essential hypertensive patients and the role of insulin resistance in these patients, a euglycemic hyperinsulinemic glucose clamp was applied in 17 essential hypertensive patients and 12 normotensive subjects. The mean glucose infusion rate was used as an indicator of insulin sensitivity (M value). This study revealed a significantly lower M value in essential hypertensive patients than in normotensive subjects. Increased plasma norepinephrine, renin activity, and aldosterone levels were observed after hyperinsulinemia for 120 minutes after glucose clamp in normotensive subjects and essential hypertensive patients. Urinary sodium excretion and fractional excretion of sodium were decreased in essential hypertensive patients as well as normotensive subjects during glucose clamp compared with the period before glucose clamp. No difference in the percent change was observed between essential hypertensive patients and normotensive subjects. These results indicate that selective insulin resistance with respect to glucose metabolism exists in essential hypertensive patients and that insulin action on renal sodium handling and pressor systems was maintained in these patients.

Aldosterone↗
PubMed1994

Left-sided unilateral pulmonary edema in postinfarction ventricular septal rupture.

Unilateral pulmonary edema (UPE) is an unusual clinical condition occurring in left heart failure (LHF). Normally, cardiogenic UPE is more pronounced on the right side when no right pulmonary artery obstructive lesion exists. In contrast, we present a rare case of left-sided UPE due to ventricular septal rupture (VSR) complicated by acute myocardial infarction. Although the precise mechanism of unilateral presentation is not clear, such a left-sided unilateral manifestation is extremely rare in LHF. This is believed to be the first reported case of left-sided UPE with postinfarction VSR.

Aged↗
PubMed1994

The role of kinins and atrial natriuretic peptide on the renal effects of neutral endopeptidase inhibitor in rats.

To further elucidate the natriuretic mechanisms of neutral endopeptidase 24.11 (NEP) inhibition, we employed a new specific NEP inhibitor, UK 73967 (UK), with or without a specific kinin receptor antagonist, Hoe 140 (Hoe), in Sprague-Dawley rats, and evaluated the renal NEP, kinins and plasma ANP simultaneously. There were no significant changes in urinary NEP, kinins, urine volume (UV) or urinary sodium excretion (UNaV) with vehicle treatment in anesthetized normotensive rats. Infused UK (10 mg/kg) significantly decreased NEP, and increased kinins, UV and UNaV. There was not a significant difference in plasma ANP between the vehicle and UK groups. Simultaneous administration of Hoe (20 nmol/kg) canceled the increases of UV and UNaV caused by UK. From these results, we conclude that inhibition of NEP may exaggerate the contribution of renal kinins to the renal water-sodium metabolism and overcome the contribution of ANP on that metabolism at least in normotensive rats.

Animals↗