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Biomedical subjects

N Iwai

Publications and source records attributed to N Iwai.

At least 127 records · Page 7Linked to original sources

Renin is expressed in rat macrophage/monocyte cells.

The cardiac renin-angiotensin system has been suggested to be involved in various pathological conditions, including hypertrophy and remodeling. However, direct evidence that renin synthesized in situ is really involved in the putative angiotensin II generation is still lacking because of the relatively low abundance of renin mRNA in cardiac tissues. We evaluated renin mRNA expression levels in the ventricles under various pathological conditions and found that renin gene expression was markedly increased in the ventricles of isoproterenol-treated rats. Renin mRNA expression levels in the ventricles of rats that had been injected with isoproterenol (150 mg/kg SC) were transiently and markedly increased to 6-, 90-, and 4-fold compared with control expression levels at 24, 72, and 120 hours, respectively, after isoproterenol administration, Immunohistochemical analysis revealed that some of the OX-42-positive macrophage/monocyte cells had a reninlike immunoreactivity. An in vitro experiment indicated that rat peritoneal macrophage/monocyte cells expressed renin mRNA in abundance. The present study confirmed that a subpopulation of macrophage/monocyte cells could express renin. Macrophage/monocyte cells may be a source of tissue renin in some pathological conditions.

Animals↗

Genetic analysis of renin gene expression in rat adrenal gland.

We examined the mechanism of the increased renin mRNA concentration in the adrenal glands of spontaneously hypertensive rats (SHR). In 52 female F2 rats (25 to 27 weeks of age) derived from SHR and Wistar-Kyoto rats, we determined blood pressure, renin mRNA concentration in the adrenal gland, plasma renin activity, plasma aldosterone concentration, and genotype of the renin gene. Eighteen of the F2 rats were fed a high salt (8%) diet for 14 days. The renin mRNA concentration in the adrenal glands showed a significant correlation with the genotype of the renin gene in the normal salt diet group (P <.0001), whereas this relationship was not observed in the high salt group. Multivariate analysis revealed that the plasma aldosterone concentration in the normal diet group was significantly explained (P=.0004, R2=.454) by plasma renin activity (P=.0005), the renin mRNA concentration in the adrenal gland (P=.0496), and the genotype of the renin gene (P=.0236). The SHR allele of the renin gene was associated with a lower aldosterone concentration. On the other hand, in the high salt diet group, only the genotype of the renin gene showed a significant relationship with plasma aldosterone concentration (P=.0237). Again, the SHR allele of the renin gene was associated with a lower aldosterone concentration. We can conclude that the higher renin mRNA concentration in the SHR adrenal glands is governed by the SHR allele of the renin gene or renin gene locus. The renin mRNA concentration in the adrenal gland exerts a minor influence on aldosterone synthesis. Paradoxically, the SHR allele of the renin gene or renin gene locus confers a lower rate of aldosterone synthesis at 25 to 27 weeks of age, the mechanism of which remains to be determined.

Adrenal Glands↗

[Optimum dose study of cefozopran in the pediatric field].

Cefozopran (SCE-2787, CZOP) was administered to patients with pediatric infections three to four times daily by intravenous injection or 30-minute intravenous drip infusion, and investigations were made in individual cases, on relationships among doses, pharmacokinetics, effects on pathogenic bacteria and MIC against them, and clinical effects. The following results on optimal doses of CZOP were obtained. 1. Clinical cases in which CZOP was administered at a dose of 10 mg (potency)/kg The subjects were 7 patients including 4 patients with pneumonia. Severities of the diseases were severe in one of the patients with pneumonia, and moderate in the other patients. The MIC against pathogenic bacteria (4 strains) isolated from these cases ranged from 0.2 to 1.56 micrograms/ml. The serum concentrations were in a range between 1.4 and 7.6 micrograms/ml at 4 hours after administration. In some cases, the serum concentrations were lower than the MICs, though slightly. In the clinical evaluation, CZOP was excellent in 3 cases, good in 2 cases and fair in 1 case. The evaluation was impossible in 1 case. The efficacy rate was 83.3% (5/6). In bacteriological evaluation, 3 out of the 4 strains disappeared. Adverse reactions and abnormal laboratory test values were not observed. 2. Cases in which CZOP was administered at a dose of 20 mg (potency)/kg The subjects were 5 patients including 2 with pneumonia, and severities were severe in one of the patients with pneumonia, and moderate in the other patients. The MICs against the pathogenic bacteria (3 strains) isolated from these cases ranged from 0.1 to 1.56 micrograms/ml. While, serum concentrations at 4 hours after administration were in a range between 3.0 and 7.7 micrograms/ml sufficiently exceeding the MICs. In the clinical evaluation, CZOP was excellent in 1 case and good in four cases, with an efficacy rate of 100% (5/5). In the bacteriological evaluation, all the 3 strains disappeared. No adverse reactions were observed, but an abnormal laboratory test value showing eosinophilia was noted in one case. 3. Cases in which CZOP was administered at a dose of 40 mg (potency)/kg The subjects were 5 patients including 3 with pneumonia. The severity was moderate in 2 of the pneumonia patients, and severe in the other three cases. The MICs against the pathogenic bacteria (4 strains) isolated from these cases were in a range between 0.1 and 0.78 micrograms/ml. The serum concentrations at 4 hours after administration ranged from 6.5 to 21.9 micrograms/ml, sufficiently exceeding the MICs. In the clinical evaluation, CZOP was excellent in 4 cases and good in 1 case, with an efficacy rate of 100% (5/5). The efficacy rate in the bacteriological evaluation was also 100%. As adverse reaction, red urine was observed in one case. Eosinophlia was noted in one case in the laboratory tests. When CZOP was administered to patients with pediatric infections at a dose of 10 mg (potency)/kg, the clinical effect of the drug was insufficient in a case in which serum concentration of CZOP at 4 hours after administration was lower than the MICs against the pathogenic bacteria. When CZOP was administered at a dose of 20 mg (potency)/kg, sufficient concentrations were obtained, and the drug efficacies were found to be excellent or good in all cases. Therefore, the effective dose normally used is considered to be 20 mg (potency)/kg. When CZOP was administered at a dose of 40 mg (potency)/kg, the drug was found to be excellent or good in all of the cases although the severities were high in more than half of the cases tested. In addition, the rate of excellent efficacies was 80% (4/5). Furthermore, no severe adverse reactions were observed. It was, therefore, confirmed that CZOP should be administered at a dose of 40 mg (potency)/kg in severe or intractable cases.

Bacterial Infections↗

Cardiac renin-angiotensin system in the hypertrophied heart.

BACKGROUND: The cardiac renin-angiotensin system (RAS) has been suggested to play an important role in heart failure and cardiac hypertrophy. In the present study, we evaluated the expression of each component of the RAS in hypertrophied heart induced by aortocaval shunt. METHODS AND RESULTS: The expression levels of renin, angiotensinogen, angiotensin-converting enzyme (ACE), and angiotensin II type Ia and Ib receptor (AT1aR and AT1bR) mRNA were determined by the reverse transcription-polymerase chain reaction method owing to the relatively low expression levels of these mRNAs in the ventricle. The expression level of renin or angiotensinogen mRNA in the ventricle was very low, more than 1000-fold lower than that in the kidney or liver, respectively. The expression of ACE mRNA in the ventricle was relatively abundant and was increased in the hypertrophied ventricle in this model, whereas no significant increases in the expression levels of AT1aR and AT1bR mRNA were observed. Administration of lisinopril attenuated the development of left and right ventricular hypertrophy in this model and was accompanied by an attenuation of the upregulation of the ACE, collagen type I-alpha, and vimentin mRNAs. Because the activity of the circulating RAS in the aortocaval shunt rats was not higher than that in the sham-operated rats, the effects of lisinopril in attenuating the ventricular hypertrophy may be due to inhibition of the increased ACE in the ventricle. CONCLUSIONS: The present study supports the importance of ACE expressed in the ventricle in the development of hypertrophy induced by aortocaval shunt.

Angiotensin II↗

The genotype of the angiotensin-converting enzyme gene and global left ventricular dysfunction after myocardial infarction.

We examined the relation between the genotype of the angiotensin-converting enzyme (ACE) gene and the development of left ventricular dysfunction, as assessed by biplane left ventriculograms, after myocardial infarction. Seventy-nine patients (deletion homozygote [DD] = 13; insertion/deletion heterozygote [ID] = 38; insertion homozygote [II] = 28) underwent cardiac catheterization twice for reevaluation of percutaneous transluminal coronary angioplasty. Subjects who had their first cardiac catheterization within 2 months from the onset of myocardial infarction were enrolled. The second cardiac catheterization was performed from 4 to 7 months after the first cardiac catheterization. ACE genotypes were determined by using the polymerase chain reaction. Ejection fraction, and end-diastolic and end-systolic volume indexes at the first cardiac catheterization were not significantly different among the 3 groups. The end-diastolic volume index at the second cardiac catheterization was not significantly different among the 3 groups. Ejection fractions (mean +/- SD) at the second catheterization in the 3 groups were 0.51 +/- 0.15 (DD), 0.56 +/- 0.12 (ID), and 0.62 +/- 0.09 (II) (p = 0.02), and were significantly lower in the DD group than in the II group. The end-systolic volume indexes (mean +/- SD) were 46 +/- 21 (DD), 43 +/- 24 (ID), and 30 +/- 14 (II) ml/m2 (p = 0.01), and were significantly greater in the DD and ID groups than in the II group.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Genes up-regulated in hypertrophied ventricle.

We isolated 8 genes whose expression is modulated during cardiac development. The expressions of 6 of these eight genes were modulated during the development of cardiac hypertrophy and/or during the transition to heart failure. In particular, the expression levels of the pro alpha-1 collagen, tissue type II transglutaminase, and vimentin genes were markedly increased during the transition to heart failure. Up-regulation of the pro alpha-1 collagen and vimentin genes may reflect activation of interstitial cells during the transition to heart failure. Up-regulation of the tissue type II transglutaminase gene during the transition to heart failure is intriguing, since this enzyme has been suggested to be involved in the activation of latent TGF-beta.

Amino Acid Sequence↗

Impaired proliferative activity of mesenchymal cells affects the migratory pathway for neural crest cells in the developing gut of mutant murine embryos.

The developmental expression of neural and cell proliferation-related antigens in guts from mutant murine embryos (Is, lethal spotted) as a model for Hirschsprung's disease was studied. The expression was examined immunohistochemically using antibodies specific for neural cell adhesion molecule (NCAM), the L1 molecule, and proliferative cell-related nuclear antigen (PCNA). Cells immunoreactive for neural components proceeded from the esophagus to the anorectum showing a one-way migratory wave between embryonal day 10 (E10) and E14 in control specimens (Is/+, +/+). The patterns of NCAM and L1 immunoreactivity in Is/Is mutant specimens was the same as in controls on E10. However, from E10.5 to E13.5, the immunoreactivity in the mutants decreased and remained in the more oral side as compared with controls. No migration of immunoreactivity was found after E14.0. Therefore, the terminal portion of the colon remained aganglionic in Is/Is mutant embryos. PCNA immunoreactivity of mesenchymal cells preceded the migratory wave of the neural specific immunoreactivity, but the PCNA-positive cells were meager and poorly organized in the mutant embryos. Deficient PCNA staining patterns were found in mesenchymal tissue rather than in the migrating cells themselves. This impaired PCNA expression may reflect a deficient microenvironment for migration such that neural crest cells cannot colonize properly.

Animals↗

Intestinal obstruction in an infant due to magnet ingestion.

A case of intestinal obstruction in an infant due to magnet ingestion is reported. The 17-month-old female swallowed seven small magnets, and developed an acute intestinal obstruction. At laparotomy, a fistula between the jejunum and the ileum which contained the seven magnets was found and resected. The patient's postoperative recovery was uneventful. Accidental magnet ingestion mandates careful observation for the development of intestinal obstruction.

Acute Disease↗

Sensation in the anal region and rectum after surgery for anorectal malformations.

Sensation of the anal region and rectum after surgery for anorectal malformations was investigated in 32 patients (17 with high type, 6 with intermediate type and 9 with low type anomaly), aged 5 to 16 years. All patients were examined as to whether or not they could appreciate sensations of touch, pain, heat and cold in the circumanal skin and in the anal canal. Rectal sensation and compliance were also examined by anorectal manometry. All patients had normal sensation in the circumanal skin, but less than half of them had normal sensation in the anal canal. Patients with normal bowel control showed a significantly higher incidence of touch sensation in the anal canal than those with fecal incontinence or constipation. It was suggested that a sensation defect of the anal canal is related to a disturbance of discrimination between flatus and feces. The results of rectal sensation and compliance showed that reduced elasticity of the neorectum and low rectal compliance were important factors of fecal incontinence after surgery for anorectal malformations.

Adolescent↗

New biofeedback therapy in children with encopresis.

Biofeedback therapy was performed in 13 patients with encopresis using newly devised computerized equipment. The patients were children, aged 6 to 11 years, who had not responded to trials of conventional therapy with a mean follow-up period of three years and two months. The biofeedback therapy was effective in 12 of the 13 patients after one course of therapy. This positive results was attributed to the computerized equipment. The patients could more easily recognize how to squeeze their anal sphincters after seeing a colored ellipse representing sphincter pressure on a monitor. The results of anorectal manometry and electromyography (EMG) showed that biofeedback therapy improved the voluntary sphincter function and rectal sensation. Therefore, biofeedback therapy might be effective in patients with encopresis whose sphincter functions are intact.

Anal Canal↗

Innervation patterns in congenital biliary dilatation.

The innervation of choledochal cysts was studied to see if the distribution of innervating ganglion cells can be utilized as a possible indicator of the damage and dilatation process of choledochus. Specimens from 32 patients aged 1 month to 12 years were stained by the immunoperoxidase method with neural tissue-specific antibodies, the innervating ganglion cells were counted and their number was correlated with the clinical severity, patient's age-at-surgery, and intraoperative cholangiographic and/or ERCP findings. In cystic dilatation, the total number of ganglion cells within the choledochal wall was significantly lower than in control specimens regardless of the diameter of the choledochal cyst, age-at-surgery, or clinical course. In fusiform dilatation, the total number of ganglion cells varied according to the severity of the clinical presentation, and the diameter of the fusiform choledochus increased in proportion to the patient's age-at-surgery. The distribution of innervating ganglion cells is thought to correlate quantitatively with the damage and dilatation process responsible for the choledochal cyst. These results may support a hypothesis that the pathogenesis of cystic dilatation proceeds antenatally or soon after birth, while that of fusiform dilatation begins after birth.

Age Factors↗

An association of multiple intestinal atresia and biliary atresia: a case report.

This is the first report of a 2-day-old girl having an association of biliary atresia and multiple intestinal atresia. She developed intractable vomiting in the first hours of life. An upper gastrointestinal series and barium enema showed jejunal atresia and rectal atresia. A laparotomy was performed on the fourth day of life. The operative findings were multiple sites of atresia of the intestine, 10 atretic sites in the small bowel, and 3 in the colon. The gall bladder was normal in size and position. After the operation, the patient's stool remained acholic and her jaundice did not resolve. On the 58th day of life, another laparotomy was performed with the presumptive diagnosis of biliary atresia. The operative finding was biliary atresia, type 3; the Kasai operation with external jejunostomy was performed. The patient suffered from postoperative cholangitis and enterocolitis because of her short bowel and subsequently died at 9 months of age. This is the first case of biliary atresia associated with multiple intestinal atresia reported in the literature.

Barium Sulfate↗

Regulation of neuronal nitric oxide synthase in rat adrenal medulla.

Neuronal nitric oxide synthase (nNOS) has been suggested to be involved in cardiovascular homeostasis. We studied the regulation of nNOS expression, determining nNOS mRNA expression levels in various tissues in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). We also investigated the effects of antihypertensive treatment with the angiotensin II antagonist hydralazine or reserpine on nNOS mRNA expression. The expression levels of nNOS mRNA and nNOS protein were determined by Northern and Western blot analysis, respectively. NADPH-diaphorase histochemistry was used to identify cells in the adrenal medulla that expressed nNOS. No significant differences in expression levels in SHR and WKY were observed in the cerebellum and brain stem. nNOS mRNA expression levels in the decapsular portion of the adrenal gland were developmentally modulated and in a 24-week-old WKY were 2.5 times higher than in an age-matched SHR. This reduced expression of nNOS mRNA in the decapsular portion of the adrenal gland of SHR seemed to be a result of hypertension in the SHR, because administration of either an angiotensin II antagonist (TCV-116) or hydralazine upregulated nNOS mRNA expression in both SHR and WKY. Marked augmentation of nNOS mRNA expression in the decapsular portion of the adrenal gland by reserpine treatment suggested an intimate relation between nNOS in the decapsular portion of the adrenal gland and the sympathoadrenal system. Reserpine treatment also increased the expression of nNOS protein; however, reserpine treatment did not affect the distribution pattern of nNOS-positive cells (NADPH-diaphorase-positive cells) in the adrenal medulla.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Medulla↗

Angiotensinogen gene and blood pressure in the Japanese population.

A molecular variant of the angiotensinogen gene with threonine instead of methionine at position 235 (ie, with M235T polymorphism) has been shown to be associated with essential hypertension in Caucasian populations. The purpose of the present study was to assess whether the M235T polymorphism was associated with essential hypertension in the Japanese population. The study population consisted of 347 subjects selected in our outpatient clinic. The clinical data included in the analyses were sex, age, body mass index, cholesterol level, genotype of the angiotensinogen gene, genotype of the angiotensin-converting enzyme gene, and systolic and diastolic blood pressure. Multiple regression analysis revealed that only body mass index was a predictor of both diastolic and systolic blood pressure in these 347 subjects, but the genotype of the angiotensinogen gene was identified as a predictor of both diastolic and systolic blood pressure in a subpopulation less than 50 years of age. However, in a subpopulation more than 50 years of age, body mass index was the only predictor of both systolic and diastolic blood pressure. Of the 347 subjects, 189 had a technically excellent echocardiogram at the initial observation period. Multiple regression analysis revealed that sex, body mass index, diastolic blood pressure, and genotype of the angiotensin-converting enzyme gene were predictors of left ventricular mass. Although subjects with the TT angiotensinogen genotype had significantly greater left ventricular mass than those with either the TM or the MM genotype, the effects of the genotype of the angiotensinogen gene on left ventricular mass were mainly due to effects on blood pressure.

Angiotensinogen↗

[Single administration toxicity studies of T-3761 in mice, rats and dogs].

Single dose toxicity studies of T-3761 were carried out in mice, rats and dogs, and the following results were obtained. 1. The approximate lethal dose of T-3761 were more than 5,000 mg/kg for mice and rats, more than 2,000 mg/kg for dogs with oral administration, and more than 5,000 mg/kg for mice and rats with subcutaneous injection. LD50 values with intravenous injection were 783 mg/kg for male mice, 832 mg/kg for female mice, 341 mg/kg for male rats, and 403 mg/kg for female rats. Two dogs given 200 mg/kg did not die but one of the two treated with 400 mg/kg died after intravenous injection. The approximate lethal dose for dog was 400 mg/kg. 2. Neither abnormal symptoms and macroscopic findings nor deaths were observed in mice and rats treated orally. Granuloma around precipitates of T-3761 at the injection site was seen in mice and rats injected subcutaneously. Slight increase of white blood cell count, serum GOT, CPK and urea nitrogen were transiently found in dogs treated orally. Neither abnormal macroscopic findings nor deaths were observed in dogs treated orally. 3. Decreased motor activity and irregular breathing were observed in mice and rats injected intravenously. In dying animals, tonic or clonic convulsions were observed. Vomiting, hyperemia of ophthalmic mucosa, edema of face, decrease of motor activity, salivation and decrease in body temperature were observed in dogs injected intravenously. At higher doses, scream and tachypnea were observed while injecting. Hematological examinations disclosed that increases in red blood cell count, white blood cell count, hematocrit and hemoglobin were found transiently. In biochemical examinations, increases in serum GOT, GPT, urea nitrogen and creatinine were found transiently. One dog intravenously injected 400 mg/kg, showed tonic convulsion and died.

Animals↗

[Three months oral repeated dose toxicity of T-3761 in beagle dogs].

A three months oral repeated dose toxicity study was carried out in beagle dogs at dosages of 300, 100, 30 and 10 mg/kg, respectively. The following results were obtained. 1. There was no death of animals during administration at any dose levels. A few to all animals in all T-3761 treated groups complained of pain at the time of extension of limbs. 2. Mild decrease of body weight was observed in 1 of the 10 animals at 300 mg/kg and 1 of the 8 animals at 100 mg/kg, respectively. 3. In urinalysis, crystals which seemed to be the test compound in the urinary sediment, were observed in 5 of the 10 animals at 300 mg/kg and 4 of the 8 animals at 100 mg/kg, respectively. 4. In blood biochemical examination, mild elevation of GPT was observed in 1 of the 10 animals at 300 mg/kg. Increase of A/G ratio was observed in males at 300, 100 and 30 mg/kg, and females at all dose levels. 5. In macroscopic findings at necropsy, blister and erosion were observed at articular cartilage of shoulder, elbow, hip, and/or knee joints in all animals at 300 and 100 mg/kg, 7 of the 8 animals at 30 mg/kg and 1 of the 8 animals at 10 mg/kg. 6. No toxic dose level was less than 10 mg/kg/day in this study.

Administration, Oral↗

[Phototoxicity and photoallergenicity tests of T-3761].

Phototoxicity and photoallergenicity tests of T-3761 (oral or percutaneous administration) were carried out in guinea pigs. Phototoxicity test of T-3761 (oral administration) was done in rats, too. The following results were obtained. 1. Compared with comparative drugs in oral administration, phototoxicity of T-3761 was equal to that of ciprofloxacin, slightly stronger than that of nalidixic acid and weaker than those of ofloxacin, enoxacin, sparfloxacin and lomefloxacin. 2. A sensibility to phototoxicity of T-3761 in rats was weaker than that in guinea pigs. 3. Phototoxicity and photoallergenicity were not observed in application of T-3761 as 10% ointment. 4. Photoallergenicity was not observed in oral administration of T-3761.

Administration, Cutaneous↗