Search PubMed⌕ Search

Biomedical subjects

S Nemoto

Publications and source records attributed to S Nemoto.

At least 19 recordsLinked to original sources
PubMed2006

[Bidirectional Glenn shunt without cardiopulmonary bypass].

From April 2002 to March 2005, 18 patients having undergone bidirectional Glenn shunt (BDG) without cardiopulmonary bypass (CPB) [off-pump BDG] were retrospectively reviewed. During BDG anastomosis, a temporary bypass was established between superior vena cava (15) or innominate vein (3) and main pulmonary artery (16) or right atrium (2). Hemodynamics and oxygenation were maintained well throughout the temporary bypass time. There was no emergent use of CPB. Mean transpulmonary pressure gradient immediately after and 24 hours after the BDG were 6.7 and 5.6 mmHg, respectively. Echocardiography showed mild flow turbulence at the anastomosis in 1 case. This simple and inexpensive technique provided good surgical view with stable hemodynamics enabling satisfactory BDG in selected cases. Furthermore, it could avoid adverse effects of CPB such as lung injury and possible blood transfusion. This experience would encourage off-pump BDG combined with more challenging procedures.

Anastomosis, Surgical↗
PubMed2005

[Successful resection of left ventricular myxoma in a toddler; report of a case].

A 4-year-old girl was found to have large left ventricular myxoma without any tumor-related symptoms. She underwent an urgent surgery and the myxoma was successfully removed through a left ventriculectomy. Great care was taken to prevent tumor-embolization during surgery, and to resect the endocardium attaching directly to the tumor. Future surveillance of this case warrants our operative technique described in this report.

Cardiac Surgical Procedures↗
PubMed2005

[Successful implantation of a metal coronary angioplasty stent for bronchomalacia of the right tracheal bronchus associated with right isomerism complex in an early infant].

One-month-old boy had severe emphysema of the right upper lobe due to the stenotic tracheal bronchus compressed between the distorted right patent ductus arteriosus (PDA) and the right aortic arch associated with right isomerism complex. He underwent a left modified Blalock-Taussig shunt and a division of the PDA on cardiopulmonary bypass. Extracorporeal lung support (ECLS) was introduced because of severe hypoxemia caused by remaining bronchomalacia of the tracheal bronchus. On postoperative day 3, a metal coronary angioplasty stent was implanted at the stenotic lesion under fluoroscopic and bronchoscopic guidance. He was successfully weaned from ECLS and then respirator after the implantation. This simple stenting procedure might be an effective alternate in the treatment of bronchomalacia or bronchial stenosis in early infancy.

Angioplasty↗
PubMed2005

[Prophylactic treatment of oral sildenafil citrate for pulmonary hypertension in an infant treated with inhaled nitric oxide after open-heart surgery].

A 3-month-old boy with coarctation of the aorta (CoA), ventricular septal defect (VSD), atrial septal defect, and severe pulmonary hypertension (PH) underwent one-stage repair consisting of patch closure of VSD and coarctation repair. Inhalation of nitric oxide (iNO) was commenced to treat residual severe PH on the day of the operation. Oral sildenafil citrate was commenced on the day 1 and iNO was gradually weaned off on the day 3. There was no "rebound", severe increase in pulmonary artery pressure, which commonly occurs after discontinuation of iNO. Then the patient was extubated without any difficulties or recurrent PH. The oral sildenafil citrate therapy was ceased on the day 8. Prophylactic use of oral sildenafil citrate for PH might be an useful alternative to shorten the duration of iNO therapy and intensive care unit (ICU) stay in the selected patients after congenital open heart surgery.

Administration, Inhalation↗
PubMed2004

Usefulness of switching to cabergoline from other dopamine agonists in patients with advanced Parkinson's disease.

Problems associated with long-term treatment of advanced Parkinson's disease (PD) include motor complications and psychotic and autonomic symptoms. We switched patients from bromocriptine (BR) or pergolide (PER) to cabergoline (CB) therapy and investigated CB's usefulness in alleviating such problems. Subjects were 30 patients (mean age 68.2 years; 13 receiving BR, 17 PER) with PD complicated by effects of long-term treatment but in whom their dose of dopamine (DA) agonist was contraindicated due to adverse reactions. Patients were switched to CB over a 2-4-week period. Hoehn-Yahr and Unified Parkinson Disease Rating Scale (UPDRS) I-IV "on" and "off" scores improved in both the BR and PER groups. CB was not discontinued due to adverse reactions in any patient. In conclusion, switching to CB is useful in patients in whom it is problematic to increase their dose of DA agonist due to motor complications or psychotic symptoms of advanced PD.

Aged↗
PubMed2004

Periodic structures and diurnal variation in blood pressure and heart rate in relation to microgravity on space station MIR.

Four Russian crew members were studied on space station MIR, and blood pressure (BP) and heart rate (HR) data were continuously collected. BP and HR data were collected on earth 1 day before orbital flight to the space station, then at weeks 8, 16 and 24 during space flight, and again 1 or 2 days after returning to earth. Time serial data for BP and HR were analyzed by spectral analysis with the MemCalc system (Suwa Trust, Sapporo, Japan). Periodic structures of diurnal variation in systolic blood pressure (SBP), diastolic blood pressure (DBP) and HR were compared at 24-hour, 12-hour and 8-hour intervals, these being determined as the main periodic components for the assessment of BP and HR variability. The 24-h mean levels of SBP and HR during space flight were unchanged. Waking SBP was not different from pre-flight values. During sleep, in-flight changes in HR did not differ from pre-flight values. SBP during sleep in orbit increased to over pre-flight values. Waking DBP was reduced during flight. The SBP and HR phases over a 24-hour cycle were shortened with a more pronounced shortening in weeks 8 and 16 compared with pre-flight values, and at week 24 recovered to preflight values. The 12, 8-hour-cycle remained unchanged, and were similar to pre-flight values. At the space station, the astronauts' mission was carried out under strict control of sleeping and waking hours; therefore, their 24-hour schedule is an artificially constructed situation. Main periodicity structures were maintained by strict control of lifestyle during long-term space flight. The conclusions reached were as follows: 1) SBP levels during sleep in a space environment increased compared with those on earth; 2) the periodicity phase of BP and HR shifted toward to 24-hour cycle as a result of long-term space flight, even though these periods shortened after a few months compared with pre-space flight values.

Adult↗
PubMed2003

Blood pressure variability during 120-day head-down bed rest in humans.

Influence of physical inactivity and microgravity to periodic structure of blood pressure was studied. Six healthy males were kept under head-down bed rest (HDBR) for 120 days. Blood pressure and heart rate (HR) were recorded by a portable sphygmomanometer and a Holter electrocardiogram, respectively. The results were analyzed by spectrum analysis. Phase, amplitude and acrophase of systolic blood pressure (SBP) by approximately 24, 12 and 8 h were measured before, 60, 120 day and after HDBR. The phase at 24, 12 and 8 h did not show significant changes during HDBR, and acrophase showed a tendency to shift to 14:00 after HDBR. Amplitude for 24 h tended to attenuate during bed rest (BR), and significantly increased after BR. The results of this study suggest that the circadian rhythm of SBP and HR were maintained by strict control of sleep, awakening and food intake in microgravity model of a long-term BR state. However, the tendency to decrease 24-h cyclic amplitude of SBP appeared to be the rhythmic modulation related to cardiovascular deconditioning.

Adaptation, Physiological↗
PubMed2001

Reproductive maternal centrosomes are cast off into polar bodies during maturation division in starfish oocytes.

Animal egg inherits a maternal centrosome from the meiosis-II spindle and sperm can introduce another centrosome at fertilization. It has been believed that in most animals only the sperm centrosome provides the division poles for mitosis in zygotes. This uniparental (paternal) inheritance of the centrosome must depend on the loss of the maternal centrosome. In starfish, suppression of polar body (PB) extrusion is a prerequisite for induction of parthenogenesis (Washitani-Nemoto et al. (1994) Dev. Biol. 163, 293-301), suggesting that the centrosomes cast off into PBs have reproducing capacity. Due to the absence of centriole duplication in meiosis II of starfish oocytes, each centrosome of a meiosis-II spindle has only one single centriole, whereas in meiosis I each has a pair of centrioles (Sluder et al. (1989) Dev. Biol. 131, 567-579; Kato et al. (1990) Dev. Growth Differ. 32, 41-49). Hence, the first PB (PB1) has two centrioles, whereas the second PB (PB2) and the mature egg have only one centriole, respectively. The present study examined the reproductive capacity of PB centrosomes by transplanting them into artificially activated eggs, and then the recipient egg nucleus with the surrounding cytoplasm was removed. A transplanted PB2 centrosome with a single centriole formed a monopolar spindle at the first mitosis, followed by formation of a bipolar spindle in the next mitosis, leading to actual cleavage and subsequent development. This proves the reproducing capacity of the single centriole in the PB2 centrosome. The behavior of the transplanted PB1 centrosome was exactly the same as in the PB2 centrosome, in spite of the difference in the number of centrioles. These results clearly show that four maternal centrioles are heterogeneous in duplicating capacity, during meiosis only one centriole in each of the centrosomes of a meiosis-I spindle pole retains duplicating capacity, the reproductive centrioles are successively cast off into PBs, and finally a mature egg inheriting a nonreproductive centriole alone is formed, and the presence of a single reproductive centriole is sufficient condition for embryonic development in starfish.

Animals↗
PubMed2001

Effects of carnitine on cardiac function after cardioplegic ischemia in neonatal rabbit hearts.

BACKGROUND: Ischemia immediately impairs myocardial fatty acid metabolism and reduces the concentration of carnitine which is an essential cofactor for fatty acid metabolism in the mitochondria. The purpose of this study was to investigate the effects of carnitine administration on recovery of cardiac function after cardioplegic ischemia in the neonatal heart where fatty acid metabolism is not a predominant source of adenosine triphosphate. METHODS: Isolated blood-perfused neonatal rabbit hearts underwent 3 hours of cold cardioplegic ischemia. The control group (n = 10) was reperfused with unmodified diluted blood. The carnitine group (n = 10) was reperfused with the blood containing 5 mM/L of carnitine. Before ischemia (base line) and after 15 and 30 minutes reperfusion, left ventricular (LV) function and LV compliance were measured using a intraventricular conductance catheter combined with an isovolumic balloon. Coronary blood flow was measured and myocardial oxygen consumption was calculated. RESULTS: Carnitine significantly improved not only LV systolic function but also LV diastolic function (p < 0.05) as well as LV compliance after ischemia. Coronary blood flow and myocardial oxygen consumption were significantly improved after ischemia in the carnitine group compared with the control group (p < 0.05). CONCLUSIONS: These results suggest that carnitine strikingly improves LV functional recovery and aerobic metabolism after cold cardioplegic arrest, and may improve cardiac performance in neonates after open heart surgery.

Animals↗
PubMed2001

Carnitine affects fatty acid metabolism after cardioplegic arrest in neonatal rabbit hearts.

BACKGROUND: Fatty acid (FA) metabolism and the contribution of carnitine to metabolism after cardioplegic arrest still remain unclear, especially in the neonatal heart where beta-oxidation is not a predominant source of adenosine triphosphate. METHODS: FA metabolism and the effects of carnitine administration were evaluated using a newborn (7-day-old) rabbit blood-perfused Langendorff model subjected to cold cardioplegic arrest. The hearts were divided into five groups; (1) perfused with unmodified diluted blood (n = 9), (2) subjected to 180 minutes of cold cardioplegic arrest and reperfused with the blood (n = 9), (3) subjected to the same ischemia and reperfused with the blood containing 40 microM/L (n = 9), (4) 0.5 mM/L (n = 5), and (5) 5 mM/L of carnitine (n = 5). During reperfusion, FA metabolism was assessed by iodine-123-labeled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid, a fatty acid. The myocardial time-radioactivity curve was then determined and a mathematical compartment analysis of the external detection was used to elucidate FA metabolism in the cardiac myocyte. RESULTS: Cold cardioplegic arrest resulted in significantly impaired FA metabolism following reperfusion. Compartment analysis suggested that FA activation in the cytosol and beta-oxidation were impaired. Carnitine supplementation in groups 3 and 4 improved FA metabolism during reperfusion. In contrast, supplementation in group 5 had no beneficial effect on FA metabolism. CONCLUSIONS: These results suggest that FA metabolism is impaired after cold cardioplegic arrest and that carnitine supplementation may improve aerobic metabolism in neonates after open heart surgery.

Animals↗
PubMed2001

Cytomegalovirus DNA among children attending two day-care centers in Tokyo.

BACKGROUND: In the USA, a high prevalence rate of cytomegalovirus (CMV) excretion among children in day-care centres was reported. However, there is no research about the prevalence rate of CMV among children in day-care centres in Japan. METHODS: The CMV excretion was studied in 54 children's saliva samples, collected from two different day-care centres in Tokyo. As a control, the prevalence of CMV was studied among 61 healthy children who did not attend any day-care centers. The CMV DNA in saliva were examined by polymerase chain reaction (PCR) analysis with one pair of primers for the immediate early region. The sequence of CMV genomes were examined in CMV PCR positive samples. RESULTS: Of the 54 saliva samples, 20.6% (6/29) and 24% (6/25) were CMV PCR positive in children at A and B day-care centres, respectively. The overall positivity of CMV PCR in saliva was 22.2% (12/54). Of the 61 saliva samples as the control study, 6.5% (4/61) were CMV PCR positive. There was a difference in the positivity in each age group of day-care centres and normal control. Each sample of the same day-care center gave conclusive and identical sequence results. CONCLUSION: We suspected that in each day-care center that there was one prevailing viral strain. We suppose that CMV infections were acquired inside the day-care centres. This is a first report which described viral transmission in day-care centres in Japan.

Child Day Care Centers↗
PubMed2001

Normal myocardial function in severe right ventricular volume overload hypertrophy.

Severe left ventricular volume overloading causes myocardial and cellular contractile dysfunction. Whether this is also true for severe right ventricular volume overloading was unknown. We therefore created severe tricuspid regurgitation percutaneously in seven dogs and then observed them for 3.5-4.0 yr. All five surviving operated dogs had severe tricuspid regurgitation and right heart failure, including massive ascites, but they did not have left heart failure. Right ventricular cardiocytes were isolated from these and from normal dogs, and sarcomere mechanics were assessed via laser diffraction. Right ventricular cardiocytes from the tricuspid regurgitation dogs were 20% longer than control cells, but neither the extent (0.171 +/- 0.005 microm) nor the velocity (2.92 +/- 0.12 microm/s) of sarcomere shortening differed from controls (0.179 +/- 0.005 microm and 3.09 +/- 0.11 microm/s, respectively). Thus, despite massive tricuspid regurgitation causing overt right heart failure, intrinsic right ventricular contractile function was normal. This finding for the severely volume-overloaded right ventricle stands in distinct contrast to our finding for the left ventricle severely volume overloaded by mitral regurgitation, wherein intrinsic contractile function is depressed.

Animals↗
PubMed2001

[Determination of 2,4,6-tri-tert-butylphenol and related compounds in foods].

An analytical method has been developed for the determination of 2,4,6-tri-tert-butylphenol (TTBP) in foods. TTBP was determined by GC/MS (SIM) after extraction from food samples using a steam distillation technique. The developed method was able to determine simultaneously 2,4-di-tert-butylphenol (2,4-DTBP), 2,6-di-tert-butylphenol (2,6-DTBP), 3,5-di-tert-butylphenol (3,5-DTBP) and 2,4-di-tert-pentylphenol (2,4-DTPP). The method was applied to analyze the residues of the 5 phenolic compounds in 101 food samples purchased from markets. TTBP was found in some samples of meat, liver and fish (muscle) at the levels of trace (tr)-0.50 ng/g, tr and tr-1.83 ng/g, respectively. 2,4-DTBP was found in some samples of vegetables, meat, liver, fish (muscle) and fish (viscera) at the levels of 1.4-10.6 ng/g, 2.7-26.4 ng/g, tr-34.2 ng/g, tr-21.6 ng/g and tr, respectively. 2,6-DTBP was found in some samples of fish (muscle) and fish (viscera) at the levels of tr-3.9 ng/g and tr, respectively. 3,5-DTBP and 2,4-DTPP were not found in any of the analyzed samples.

Antioxidants↗
PubMed2001

[Determination of bisphenol A in foods using GC/MS].

An analytical method using GC/MS was developed for bisphenol A (BPA) in foods and BPA was determined in canned foods and fresh foods such as vegetables, fruit and meat. BPA was extracted with acetone from the samples and the extract was concentrated at under 40 degrees C in vacuo to afford an aqueous solution, which was washed with hexane after alkalization and extracted with 50% diethyl ether-hexane after acidification. Extracts were cleaned up on a PSA and/or a C18 cartridge column, and BPA was derivatized with heptafluorobutyric anhydride and determined by GC/MS (SIM). This method was applicable to the detection and determination of BPA residues in food samples at the level of 1 ng/g. Among canned foods, BPA was found in 6 corned beef, 1 chicken, 9 sweet corn and 3 bean samples at the levels of 17-602 ng/g, 212 ng/g, 2.3-75 ng/g and 3.5-26 ng/g, respectively. BPA was also detected in 1 retort soup and 1 retort pack product at the levels of 11 ng/g and 86 ng/g, respectively. As for dairy products, BPA was not detected in butter and milk. Among fresh foods, BPA was detected in 2 fish and 3 liver samples at the levels of trace (tr)-6.2 ng/g and tr-2.2 ng/g, respectively. In vegetables, fruits and chocolates, a trace level of BPA was detected in only 1 chocolate. Traces of BPA were also detected in 3 samples of 6 boxed lunches.

Animals↗
PubMed2000

Microtubule depolymerization normalizes in vivo myocardial contractile function in dogs with pressure-overload left ventricular hypertrophy.

BACKGROUND: Because initially compensatory myocardial hypertrophy in response to pressure overloading may eventually decompensate to myocardial failure, mechanisms responsible for this transition have long been sought. One such mechanism established in vitro is densification of the cellular microtubule network, which imposes a viscous load that inhibits cardiocyte contraction. METHODS AND RESULTS: In the present study, we extended this in vitro finding to the in vivo level and tested the hypothesis that this cytoskeletal abnormality is important in the in vivo contractile dysfunction that occurs in experimental aortic stenosis in the adult dog. In 8 dogs in which gradual stenosis of the ascending aorta had caused severe left ventricular (LV) pressure overloading (gradient, 152+/-16 mm Hg) with contractile dysfunction, LV function was measured at baseline and 1 hour after the intravenous administration of colchicine. Cardiocytes obtained by biopsy before and after in vivo colchicine administration were examined in tandem. Microtubule depolymerization restored LV contractile function both in vivo and in vitro. CONCLUSIONS: These and additional corroborative data show that increased cardiocyte microtubule network density is an important mechanism for the ventricular contractile dysfunction that develops in large mammals with adult-onset pressure-overload-induced cardiac hypertrophy.

Animals↗
PubMed2000

Synthesis and characterization of water-soluble silver(I) complexes with L-histidine (H2his) and (S)-(-)-2-pyrrolidone-5-carboxylic acid (H2pyrrld) showing a wide spectrum of effective antibacterial and antifungal activities. Crystal structures of chiral helical polymers [Ag(Hhis)]n and ([Ag(Hpyrrld)]2)n in the solid state.

Two water-soluble, silver(I) complexes showing a wide spectrum of effective antibacterial and antifungal activities, i.e., ([Ag(Hhis)].0.2EtOH)2 (1; H2his = L-histidine) and [Ag(Hpyrrld)]2 (3; H2pyrrld = (S)-(-)-2-pyrrolidone-5-carboxylic acid) were prepared. In aqueous solution 1 and 3 were present as dimers, whereas in the solid state they were polymers. Crystallization of 1 by slow evaporation and/or vapor diffusion gave water-insoluble crystals of [Ag(Hhis)]n (2) showing modest antimicrobial activities. The complex 1 in the solid state is a polymer formed by intermolecular hydrogen-bonding interactions between dimeric [Ag(Hhis)]2 cores, while 2 is a different polymer without a core complex. X-ray crystallography revealed that 2 was a left-handed helical polymer consisting of a bent, 2-coordinate silver(I) atom bonding to the Namino atom of one Hhis- ligand and the N pi atom of a different Hhis- ligand. Of particular note is the fact that Ocarboxyl atoms do not participate in the coordination. X-ray crystallography also revealed that 3 was a left-handed helical polymer formed by self-assembly of dimeric [Ag(Hpyrrld)]2 cores with an intramolecular metal(I)-metal(I) interaction (Ag-Ag distance, 2.9022(7) A). The FT-IR and the solid-state 13C and 15N NMR spectra showed that the dimeric core of 1 was formed through Ag-N bonds, while that of 3 was formed through Ag-O bonds. The molecular ions of 1 and 3 were detected by the positive-ion electrospray ionization (ESI) mass spectrometry. For 1-3, characterization by elemental analysis, TG/DTA, FT-IR, and variable-temperature solid-state 13C NMR and room-temperature 15N NMR measurements was performed, and for 1 and 3, that by solution molecular weight measurements and solution (109Ag, 1H, and 13C) NMR spectroscopies was also carried out. The antibacterial and antifungal activities of 1 and 3 were remarkable and comparable to those of the previous silver(I)-N-heterocycle complexes.

Anti-Bacterial Agents↗
PubMed2000

Effects of gene deletion of the tissue inhibitor of the matrix metalloproteinase-type 1 (TIMP-1) on left ventricular geometry and function in mice.

Alterations in the expression and activity of the matrix metalloproteinases (MMPs) and the tissue inhibitors of the MMPs (TIMPs) have been implicated in tissue remodeling in a number of disease states. One of the better characterized TIMPs, TIMP-1, has been shown to bind to active MMPs and to regulate the MMP activational process. The goal of this study was to determine whether deletion of the TIMP-1 gene in mice, which in turn would remove TIMP-1 expression in LV myocardium, would produce time-dependent effects on LV geometry and function. Age-matched sibling mice (129Sv) deficient in the TIMP-1 gene (TIMP-1 knock-out (TIMP-1 KO), n=10) and wild-type mice (n=10) underwent comparative echocardiographic studies at 1 and 4 months of age. LV catheterization studies were performed at 4 months and the LV harvested for histomorphometric studies. LV end-diastolic volume and mass increased (18+/-4 and 38+/-3%, respectively, P<0.05) at 4 months in the TIMP-1 KO group; a significant increase compared to wild-type controls (P<0.05). At 4 months, LV and end-diastolic wall stress was increased by over two-fold in the TIMP-1 KO compared to wild type (P<0.05). However, LV systolic pressure and ejection performance were unchanged in the two groups of mice. LV myocyte cross-sectional area was unchanged in the TIMP-1 KO mice compared to controls, but myocardial fibrillar collagen content was reduced. Changes in LV geometry occurred in TIMP-1 deficient mice and these results suggest that constitutive TIMP-1 expression participates in the maintenance of normal LV myocardial structure.

Animals↗