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Biomedical subjects

N Nagata

Publications and source records attributed to N Nagata.

At least 145 records · Page 8Linked to original sources
PubMed1997

The effect of hypothermic cardiopulmonary bypass on plasma adrenomedullin in adult cardiac surgical patients.

Cardiopulmonary bypass (CPB) can evoke a systemic inflammatory response, which is accompanied by an increase in plasma cytokines that may stimulate the production of adrenomedullin (AM), a potent vasodilator peptide. This study was undertaken to investigate whether CPB influenced plasma AM concentration in 10 patients undergoing cardiac surgical procedures. We found that the plasma AM concentration increased significantly after the commencement of CPB, with the greatest increase observed at weaning from bypass (P < 0.01). After CPB, plasma AM concentration declined but still exceeded baseline significantly 24 h postoperatively. The increase in the plasma AM concentration at weaning from CPB correlated significantly with aortic cross-clamp time (r = 0.74, P < 0.05). The authors conclude that the secretion of AM into circulation is augmented by CPB in patients undergoing cardiac surgery, which suggests a possible role of AM in cardiovascular regulation during and after surgery with CPB.

Adrenergic beta-Agonists↗
PubMed1997

The effect of dopamine on hepatic blood flow in patients undergoing epidural anesthesia.

We studied the effect of dopamine on hepatic blood flow during epidural anesthesia with the infusion of hydroxyethyl starch (HES). Hepatic blood flow was measured noninvasively via indocyanine green (ICG) clearance (indices: K [ICG disappearance rate] and R15 [15-min ICG retention rate]). Group C (n = 7) received no epidural anesthesia, Group E (n = 14) received epidural anesthesia, and Group E + D (n = 7) received a dopamine infusion (5 microg x kg(-1) x min(-1)) during epidural anesthesia. Epidural blockade extended from a median of T5 (T4-7) to L4 (L3-5) in Group E and from T5 (T4-7) to L4 (L3-S1) in Group E + D. Mean arterial pressure was maintained at preanesthetic levels in Groups E and E + D. K decreased and R15 increased in Group E (P < 0.05). In Groups C and E + D, K decreased and R15 increased slightly, but not significantly. K was smaller and R15 greater in Group E than in Group C (P < 0.05). We conclude that hepatic blood flow is decreased by epidural anesthesia, despite normotension maintained by continuous infusion of HES, but that this decrease in flow is reversed by the addition of a dopamine infusion.

Adult↗
PubMed1997

Effects of endurance training on superoxide dismutase activity, content and mRNA expression in rat muscle.

1. The purpose of the present study was to investigate the changes in superoxide dismutase (SOD) isoenzyme (Mn(2+)-SOD and Cu2+, Zn(2+)-SOD) activities, contents and mRNA expressions in rat skeletal muscle during endurance training and a single bout of exercise. 2. Thirty-eight male Wistar rats were divided into untrained (U) and trained (T) groups. The T group rats were treadmill-trained for 9 weeks. The activity, content and mRNA expression of Mn(2+)-SOD and Cu2+, Zn(2+)-SOD were determined in the soleus muscle of each rat. 3. Mn(2+)-SOD activity and content in the T group were significantly higher than in the U group, both at rest (22 and 21%, respectively) and after exercise (24 and 46%, respectively), while a single bout of exercise affected neither the activity nor content of Mn(2+)-SOD in either group. 4. The content of Cu2+,Zn(2+)-SOD in both groups was not different at rest and after exercise, although its activity at rest was significantly higher in the T group than in the U group (by 29%). 5. After exercise, the expression of Mn(2+)-SOD mRNA was markedly attenuated only in the U group (49%); the expression of Cu2+,Zn(2+)-SOD mRNA was not influenced by exercise. 6. Our results suggest that adequate endurance training increases both the activity and content of Mn(2+)-SOD and that untrained rats are rather susceptible to oxidative stress during physical exercise. It thus appears that Mn(2+)-SOD provides a reliable index of physical training. 7. The results obtained in the present study also suggest that muscle has the capacity of responding to training in such a manner as to reduce the potential harm arising from the accumulation of oxygen free radicals resulting from enhanced metabolic activity.

Animals↗
PubMed1997

Interstitial pneumonitis and fibrosis associated with the inhalation of hair spray.

We describe a 49-year-old female Japanese hairdresser who presented with a 5-year history of exertional dyspnea, a nonproductive cough, and occasional febrile episodes. Histological analysis revealed interstitial fibrosis with mononuclear cell infiltration, foreign body granuloma, and numerous intra-alveolar macrophages and multinucleated giant cells of foreign body type. Arterial blood gas, pulmonary function studies and computed tomographic findings demonstrated improvement 6 months after cessation of exposure to the salon. Bronchoalveolar lavage fluid findings suggested that the development of lung disease in this case was triggered by an allergic mechanism rather than the storage of hair spray ingredients in the lung.

Beauty Culture↗
PubMed1997

Features of idiopathic pulmonary fibrosis with organizing pneumonia.

To characterize the clinical features of patients with idiopathic pulmonary fibrosis (IPF) having organizing pneumonia (OP), we retrospectively reviewed the clinical charts, chest X-rays, CT scans, and transbronchial lung biopsy (TBLB) specimens of patients with IPF. Patients with IPF and OP had a subacute onset of symptoms (within 2 months) (87.5%), leukocytosis (> 10,000/mm3) (62.5%), and a strong C-reactive protein (CRP) reaction (> 3+) (75%). Some of these features were distinctly different from those of IPF patients without OP (subacute onset of symptoms 0%, leukocytosis 0%, strong CRP reaction 16.7%). In the patients with IPF with OP, A-aDo2 and semiquantitative scores of chest X-ray abnormalities improved significantly after prednisolone treatment. Those abnormalities improved only slightly in the patients with IPF without OP. Diffusing capacity remained decreased and abnormal interstitial infiltration persisted, even after prednisolone treatment in the patients with IPF with or without OP. Clinical features of IPF patients with OP differed from those of patients with IPF without OP. IPF patients with OP showed good clinical response to corticosteroid therapy. These findings warrant further study of the presence of OP in TBLB specimens in predicting corticosteroid responsiveness and prognosis of patients with IPF.

Cryptogenic Organizing Pneumonia↗
PubMed1997

Endurance training improves the resistance of rat diaphragm to exercise-induced oxidative stress.

The current study was designed to test the hypothesis that endurance training improves the ability of the diaphragm muscle to resist exercise-induced oxidative stress. Twenty-eight male Wistar rats were assigned to either untrained or trained groups. Trained rats were treadmill-trained for 9 wk. Each group was subdivided into acutely exercised or nonexercised groups. Diaphragm muscle from each rat was analyzed to determine the levels of certain antioxidant enzymes: Mn-superoxide dismutase (Mn-SOD), Cu,Zn-superoxide dismutase (Cu,Zn-SOD), glutathione peroxidase, and catalase. In addition, interleukin-1 and myeloperoxidase levels were determined. Endurance training upregulated all of the antioxidant enzymes. Conversely, acute exercise increased glutathione peroxidase and catalase in untrained rats, while it had no overt effect on any antioxidant enzymes in trained rats. Both Mn-SOD and Cu,Zn-SOD contents and activities were increased with endurance training. However, the mRNA expressions of both forms of SOD did not show any significant change with endurance training. Acute exercise also increased the levels of interleukin-1 and myeloperoxidase in untrained rats but not in trained rats. Moreover, acute exercise significantly increased the ability of neutrophils to produce superoxide, especially in untrained rats. The results from this study demonstrate that endurance training can upregulate certain antioxidant enzyme activities in rat diaphragm muscle, indicating the potential for improvement of the resistance to intracellular reactive oxygen species. The results of this study also suggest that acute exercise may cause oxidative damage in rat diaphragm through the activation of the inflammatory pathway and that endurance training may minimize such an extracellular oxidative stress by acute exercise.

Animals↗
PubMed1997

Regulation by calcitonin and glucocorticoids of calcitonin receptor gene expression in mouse osteoclasts.

We previously studied regulation of the calcitonin (CT) receptor (CTR) by glucocorticoid (GC) and CT in cultures of mature mouse osteoclast-like cells (OCLs). The present studies were designed to examine the interaction of CT and GC in regulation of the CTR in osteoclasts and the molecular mechanisms involved. Treatment of OCLs with 10(-7) M dexamethasone (Dex) increased the CTR number in a time-dependent manner, whereas treatment with 10(-9) M salmon CT (sCT) reduced CTR number; neither treatment changed receptor affinity. Dex pretreatment somewhat antagonized the CT-induced reduction in [125I]sCT specific binding. Dex increased, and sCT pretreatment decreased, the sCT-responsive adenylate cyclase activity in parallel with the change in receptor binding. Dex treatment resulted in an increase in CTR messenger RNA (mRNA) levels, as assessed by reverse transcription-PCR, indicating that the increased CTR number was mediated by de novo CTR synthesis. This effect was specific to GCs and was not reproduced by mineralocorticoids or sex steroids. Treatment with sCT resulted in a rapid and profound reduction in CTR mRNA expression, and this reductions was somewhat delayed by Dex pretreatment. OCLs were treated with 5,6-dichloro-1 beta-D-ribofuranosyl benzimidazole to enable estimation of the mRNA decay rates in the absence of ongoing transcription. The stability of CTR mRNA was similar to the control value in Dex-treated OCLs, suggesting that the effect of Dex may be due to changes in transcriptional activity. Interestingly, transcriptional inhibition by 5,6-dichloro-1 beta-D-ribofuranosyl benzimidazole abolished the ability of CT to reduce CTR mRNA levels, suggesting that CT may act by increasing the rate of CTR mRNA decay, and that this effect requires ongoing transcription. The 3'-untranslated region of the mouse CTR mRNA contains four copies of the AUUUA motif, as well as other A/U-rich sequences, which have been shown to determine the stability of other mRNA transcripts. The stability results were consistent with the results of the nuclear transcript run-on assay, which indicated that treatment with Dex enhanced the rate of transcription, whereas CT had no effect. These results show that GC and CT influence CTR expression by distinct mechanisms and provide the basis for identification of the cellular factors involved.

Animals↗
PubMed1997

Lack of association between the Trp64 Arg mutation in the beta 3-adrenergic receptor gene and obesity in Japanese men: a longitudinal analysis.

The beta 3-adrenergic receptor (beta 3AR) is implicated in the regulation of thermogenesis and lipolysis, and it is suggested that the Trp64 Arg mutation in this receptor may contribute to the development of obesity. To examine whether the Trp64 Arg mutation had any effect on body weight during adult life, the beta 3AR genotype was determined in 186 unselected Japanese men, most of whom had records of body weight measured yearly from 25-53 yr of age. Of them, 26 subjects were diagnosed as having noninsulin-dependent diabetes mellitus (NIDDM) and 41 as having impaired glucose tolerance. There were 6 subjects (3%) with homozygous mutation, 67 (36%) with heterozygous mutation, and 113 (61%) with normal allele. Among the 3 genotypes, there were no significant differences in body mass index (BMI) at any age between 25-53 yr and the prevalence of NIDDM at the age of 53 yr. When longitudinal changes in body weight were compared between subjects with and without mutation, the former were less prone to gain weight than the latter. The frequency of the mutant allele was 1) not different among obese (BMI, > 26.4), intermediate (BMI, 22-26.4), and nonobese (BMI, < 22.0) subjects (0.21, 0.22, and 0.26, respectively; P = 0.77); 2) lower in subjects with NIDDM than in those without it, but the difference was insignificant (0.12 vs. 0.23; P = 0.07); and 3) similar between 186 unselected men and another group of 100 patients with NIDDM that were randomly selected for comparison (0.21 vs. 0.23). These results suggest that the beta 3AR is not a major contributing factor to obesity or NIDDM in Japanese men.

Adult↗
PubMed1997

Antitumorigenic activities of chalcones (II). Photo-isomerization of chalcones and the correlation with their biological activities.

Some chalcones are known to be phototransformed in a solution from trans into cis isomers. 3-Hydroxy-3'-methylchalcone (3'Me-3-C) has been found to be isomerized from trans into cis by irradiation of daylight in the methanolic solution. The presence of a hydroxyl in the 2'- or 4-position in the trans-chalcone structure prevents phototransformation into cis isomers. The feasibility of phototransformation of chalcones was discussed using UV-spectral analysis. The phototransformed cis-3'Me-3-C showed more potent antitumorigenic activity than the original trans form. The generally recognized parallelism between antitumorigenic and antiinflammatory activities was not observed in trans and cis 3'-Me- and 4'-Me-3C, which are antitumorigenic but inactive in 12-O-tetradecanoylphorbol 13-acetate (TPA)- and arachidonic acid (AA)-induced mouse ear edema. However, inhibitory activity against ornithine decarboxylase (ODC) was commonly observed in both naturally occurring and synthetic antitumorigenic chalcones.

Animals↗
PubMed1997

Serum cholesterol reduction and cholesterol absorption inhibition in CaCo-2 cells by a soyprotein peptic hydrolyzate.

The serum cholesterol level in rats was significantly decreased in a group fed on a soyprotein peptic hydrolyzate (SPH) when compared with a group fed on a casein tryptic hydrolyzate (CTH). The fecal excretion of total steroids was significantly greater with rats fed on the SPH diet when compared with the CTH diet. The results of CaCo-2 studies clearly suggest that the suppression of cholesterol absorption in the intestinal epithelia is part of the mechanism for the hypocholesterolemic action induced by SPH.

Animals↗
PubMed1997

Effects of mineral fibers on the expression of genes whose product may play a role in fiber pathogenesis.

To determine which factors are useful for the risk assessment of man-made fibers, we examined the gene expression of proinflammatory cytokines, growth factors, manganese superoxide dismutase (MnSOD), and inducible nitric oxide synthase (iNOS) in mineral fiber-exposed rats by means of reverse transcription-polymerase chain reaction (RT-PCR). Male Wistar rats received a single intratracheal instillation of either saline (control) or two types of fibers (2 mg of Union Internationale Centre le Cancer (UICC) chrysotile or alumina silicate refractory ceramic fiber [RCF]). Expression of interleukin-1 alpha (IL-1 alpha), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), platelet-deriving growth factor-A, (PDGF-A), platelet-deriving growth factor-B (PDGF-B), transforming growth factor beta 1 (TGF-beta 1), basic fibroblast growth factor (bFGF), MnSOD, and iNOS mRNA from lung and lipopolysaccharide (LPS)-stimulated alveolar macrophages (AM) were assessed by RT-PCR. Among these factors, IL-1 alpha, TNF-alpha, IL-6, bFGF, and iNOS would be the possible parameters for the risk assessment of fibers. In a follow-up study, we investigated the time course (3 days, 1 week, 1 month, and 3 months) of expression of IL-1 alpha and TNF-alpha by LPS-stimulated AM exposed to mineral fibers in vivo. Male Wistar rats were instilled intratracheally with saline or fibers (2 mg of Union Internationale Contre le Cancer UICC crocidolite or potassium octatitanate whisker [TW]). The expression of IL-1 alpha mRNA by fibers was greatest in TW, crocidolite, chrysotile, and RCF-instilled rat AM, in that order. The increase of IL-1 alpha and TNF-alpha mRNA in AM peaked at 1 month and 3 days after exposure to crocidolite or TW, respectively. The expression of IL-1 alpha by fibers (crocidolite, chrysotile, TW, and RCF) may be a good indicator of the pathologic potential of fibers.

Administration, Inhalation↗
PubMed1997

Expression of matrix metalloproteinases, tissue inhibitors of metalloproteinases, and extracellular matrix mRNA following exposure to mineral fibers and cigarette smoke in vivo.

To determine the effect of mineral fibers and cigarette smoke on remodeling of lung tissues, we examined matrix metalloproteinase-1 (MMP-1), MMP-2, tissue inhibitors of metalloproteinase-1 (TIMP-1), TIMP-2, and types I and IV collagen mRNA levels from rat lungs exposed to mineral fibers and/or cigarette smoke in vivo. Male Wistar rats (10 weeks of age) were given a single intratracheal instillation of 2 mg of chrysotile or alumina silicate ceramic fibers (RCF). Animals were then exposed to cigarette smoke (side stream) 5 days per week for 4 weeks. Transcriptional levels of mRNA extracted from the lungs were assessed by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). Exposure to cigarette smoke induced increases in MMP-1 and TIMP-1 mRNA levels and decreased TIMP-2 and type I collagen mRNA levels in lung. Chrysotile or RCF stimulated the expression of MMP-1 mRNA in the lung. The mineral fibers and cigarette smoke had more than additive effects on the expression of MMP-2 and TIMP-1 in the lung. These data suggest that the imbalance of the expression of MMPs, TIMPs, and extracellular matrix may be associated with the remodeling of lung tissues induced by mineral fibers and/or cigarette smoke.

Administration, Inhalation↗
PubMed1997

Characterization of amiodarone pneumonitis as related to inflammatory cells and surfactant apoprotein.

STUDY OBJECTIVE: To characterize the inflammation observed in amiodarone-induced pneumonitis. DESIGN: The density of inflammatory cells in BAL fluid (BALF) and lung interstitium was quantified in a rat model of amiodarone pneumonitis. Immunoperoxidase staining for surfactant apoprotein was evaluated in lung tissue. ANIMALS AND INTERVENTIONS: Male Fischer 344 rats weighing 170 to 180 g received amiodarone, 150 mg/kg/d, suspended in 0.5% methylcellulose by gavage 5 d/wk. Control animals were given only methylcellulose. Rats were killed after 3, 5, 7, 9, and 12 weeks. Histologic sections were prepared for hematoxylin-eosin staining and the immunoperoxidase method. MEASUREMENTS AND RESULTS: Significant positive correlations between the density of neutrophils in BALF and the interstitium were seen at 5 weeks (r=0.90, p<0.05) and 7 weeks (r=0.90, p<0.05). Significant positive correlations were observed between the density of lymphocytes in BALF and the interstitium at 9 weeks (r=0.90, p<0.05) and 12 weeks (r=0.90, p<0.05). The density of type II pneumocytes was significantly increased in the amiodarone-fed rats. Extracellular surfactant apoprotein was found in the alveolar space and the cytoplasm of type II pneumocytes, Clara cells, and large, foamy macrophages throughout drug treatment. Extracellular surfactant apoprotein filled some alveoli at 9 weeks. CONCLUSIONS: The density of lymphocytes and neutrophils increased significantly in the BALF and the lung interstitium throughout amiodarone administration. The relationship between the density of lymphocytes in BALF and in the interstitium differed from that of neutrophils. In addition, amiodarone caused hyperplasia of type II pneumocytes and deposition of conglomerated, extracellular surfactant apoprotein in the alveolar space.

Amiodarone↗
PubMed1997

Hysterotomy and selective delivery of an intrauterine dead fetus to prevent intrauterine death or brain damage of the surviving fetus in monochorionic twin pregnancy.

When pregnancy is continued after death of one fetus in monochorionic twin pregnancy, the surviving fetus sometimes exhibits intrauterine death or brain damage. Hysterotomy and selective delivery of an intrauterine dead fetus was performed in order to prevent intrauterine death or brain damage of the surviving fetus at 24 weeks' gestation in a monochorionic twin pregnancy. The healthy baby except for immaturity was born at 30 weeks' gestation, and exhibited no brain damage postnatally. When one fetus has died in utero before maturity of surviving fetus, hurried selective delivery of dead fetus should be one of the useful treatments to prevent intrauterine death or brain damage of the surviving fetus in monochorionic twin pregnancy.

Adult↗
PubMed1997

Ultrasonographic findings in the periventricular region in premature newborns with antenatal periventricular leukomalacia.

Cranial ultrasonography was carried out at least three times a week during the first 16 days of life in all 53 premature newborns born within study period. If a cyst of more than three mm was detected in the periventricular region by fourteenth day of life, it was judged to be antenatal PVL. Periventricular echodensity was classified into mild, moderate or severe periventricular echodensity (PVE). Among 53 newborns, 11 babies (20.8%) were diagnosed as having antenatal PVL. Cysts were observed in the first two days in 9 cases (81.8%) out of 11 babies, and in bilateral periventricular regions in 8 cases (72.7%) out of 11 babies. All 3 babies with severe PVE in the periventricular region had PVL at the time of diagnosis or developed PVL shortely after severe PVE was detected.

Brain Diseases↗
PubMed1997

Fractional esterification rate of cholesterol in high density lipoprotein is correlated with low density lipoprotein particle size in children.

Small low density lipoprotein (LDL) particles are thought to be more atherogenic than larger LDL particles, although this association may depend on plasma triglyceride (TG) and high density lipoprotein (HDL) levels. To help prevent coronary artery disease (CAD), it may be useful to understand risk factors during childhood and adolescence. In the present study, we evaluated low density lipoprotein particle size (LDL-size) by 2-16% gradient gel electrophoresis in 70 healthy children (30 boys and 40 girls) along with conventional lipid and lipoprotein parameters which are thought to affect LDL-size. The fractional and molar esterification rates (FER and MER) of cholesterol in plasma and HDL were also determined. As expected, plasma levels of TG, HDL-cholesterol (HDL-C) and apoA-I were closely associated with LDL-sizes in both sexes (boys: r = -0.694, 0.708 and 0.701, girls: r = -0.579, 0.551 and 0.539, P < 0.001). However, a closer association was found between FER in HDL (FER(HDL)) and LDL-size (boys: r= -0.874, girls: r= -0.642, P < 0.001). In a stepwise multiple regression analysis, FER(HDL) alone accounted for 76% and 41% of the variability in LDL-size in boys and girls, respectively. MER in HDL accounted for additional 4% and 19% in boys and girls, respectively. Other parameters, including plasma TG, HDL-C and apoA-I had no significant additional effects. Thus, the determination of FER(HDL) is useful to predict the particle size of LDL in children.

Adolescent↗
PubMed1997

Solitary "amyloid ulcer" localized in the sigmoid colon without evidence of systemic amyloidosis.

In a 51-yr-old man, colonoscopy for heme-positive stools revealed a solitary "amyloid ulcer" localized in the sigmoid colon. There were no clinical symptoms suggesting amyloidosis, and additional examination revealed no findings characteristic of amyloidosis or any chronic inflammatory disease. Ischemic change as a result of amyloid infiltration into the vessel wall may lead to formation of an ulcer in the affected bowel. Although local resection can be considered for a symptomatic and well defined lesion, it should be kept in mind that amyloid can present in various forms and follow various courses, such as the spontaneous healing that occurred in our patient.

Amyloidosis↗