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Biomedical subjects

K Aoki

Publications and source records attributed to K Aoki.

At least 37 records · Page 2Linked to original sources
PubMed2005

A prospective randomized trial of either famotidine or omeprazole for the prevention of bleeding after endoscopic mucosal resection and the healing of endoscopic mucosal resection-induced ulceration.

BACKGROUND: It has been reported that inhibitors of gastric acid secretion prevent bleeding after endoscopic mucosal resection for mucosal gastric neoplasm. However, uncertain whether an histamine2-receptor antagonist or proton-pump inhibitor is more effective. AIM: To evaluate prospectively the effectiveness of famotidine or omeprazole for ulcer management after endoscopic mucosal resection. METHODS: From July 2003 to October 2004, 57 patients were randomly assigned to famotidine or omeprazole for the management of endoscopic mucosal resection. Both drugs were given intravenously for the first 2 days, thereafter by mouth. The bleeding rates after endoscopic mucosal resection, the effects on the healing of endoscopic mucosal resection-induced ulceration, and cost-benefits were compared. RESULTS: Twenty-eight patients received famotidine and 29 received omeprazole. No significant difference was observed between the two groups in patient characteristics. The bleeding rates after endoscopic mucosal resection were not significantly different (18% vs. 14%) between the groups. Similarly, no differences were seen in the size of the endoscopic mucosal resection-induced ulceration at 1, 30 and 60 days after resection between groups. The total costs of anti-secretory agents demonstrated a significant cost-benefit to those treated with famotidine (10,420 yen vs. 17,782 yen). CONCLUSIONS: Famotidine is suggested as a better alternative to omeprazole for the management of endoscopic mucosal resection, as it showed a clear cost-benefit, and the healing results after endoscopic mucosal resection were similar for the two treatment strategies.

Aged↗
PubMed2005

[Nifekalant hydrochloride as an effective treatment for postoperative ischemic heart disease].

We experienced 2 effective cases of nifekalant hydrochloride. One patient was 76-year-old female who underwent emergent coronary artery bypass grafting (CABG) because of unstable angina pectoris (AP) and ventricular fibrillation (Vf). Her cardiac function had been decreased preoperatively due to old myocardial infarction (OMI). One day after CABG, she revealed sustained ventricular tachycardia (VT) and Vf. Although administrations of neither lidocaine hydrochloride nor magnesium sulfate were effective, nifekalant hydrochloride finally stopped the life-threatening arrhythmia without hypotension. Another patient was 77-year-old male who underwent CABG and Dor operation. His cardiac function also had been decreased due to OMI. He revealed VT attack at midnight 3 days after operation. VT attack still appeared at next 2 midnight under lidocaine hydrochloride infusion, but finally it has disappeared after starting a drip infusion of nifekalant hydrochloride. Nifekalant hydrochloride is quite useful as a new therapeutic strategy for uncontrollable VT and Vf and for the patient who has a reduced left ventricular function because it has an inotropic effect.

Aged↗
PubMed2005

[Ultrasound carotid artery plaque morphology and perioperative stroke risk in patients undergoing coronary artery bypass grafting].

OBJECTIVE: To determine the influence of carotid artery plaque (CAP) morphology on perioperative stroke in coronary artery bypass grafting (CABG). PATIENTS AND METHODS: Ninety-three patient undergoing CABG were studied. CAPs and other lesions including intima-media thickness (IMT) and stenosis were examined by using ultrasound imaging. CAPs were morphologically classified as either homogeneous (HmP) or heterogeneous (HtP). RESULTS: Mean and max IMT were 1.26 +/- 0.15 and 2.44 +/- 0.76 mm. Mean total plaque score was 15.75 +/- 6.82. HmP and HtP were seen in 80 (86.0%) and 54 (58.1%) patients. Stenosis greater than 50% was found in 22 (23.7%) patients. HtP was significantly associated with age (p<0.05), diabetes and severity of coronary artery disease (p<0.01) and stenosis was associated with diabetes and history of cerebrovascular events (p <0.05). Late postoperative stroke occurred in 3 (3.2%) patients during hospitalization. One of them had 90% stenosis in the carotid artery. The others had no carotid stenosis. In all of the 3, the predominant plaques were heterogeneous. CONCLUSION: CAP morphology in patients undergoing CABG was detailed. As well as stenotic lesion, plaque heterogeneity may be a risk factor for perioperative stroke. Diabetes is associated with severity of both plaque heterogeneity and stenosis.

Adult↗
PubMed2004

Double helicity asymmetry in inclusive midrapidity pi0 production for polarized p+p collisions at square root s = 200 GeV.

We present a measurement of the double longitudinal spin asymmetry in inclusive pi(0) production in polarized proton-proton collisions at sqrt[s]=200 GeV. The data were taken at the Relativistic Heavy Ion Collider with average beam polarizations of 0.27. The measurements are the first in a program to study the longitudinal spin structure of the proton, using strongly interacting probes, at collider energies. The asymmetry is presented for transverse momenta 1-5 GeV/c at midrapidity, where next-to-leading-order perturbative quantum chromodynamic (NLO pQCD) calculations well describe the unpolarized cross section. The observed asymmetry is small and is compared to a NLO pQCD calculation with a range of polarized gluon distributions.

Journal Article↗
PubMed2004

New monoclonal antibody (AIC) identifies interstitial cells of Cajal in the musculature of the mouse gastrointestinal tract.

Interstitial cells of Cajal (ICC) are pacemaker cells for the spontaneous muscular contractions and neuromodulators that mediate neurotransmission from enteric neurons to smooth muscle cells in the gastrointestinal (GI) tract. They express c-Kit, and the antibody for c-Kit (especially ACK2) has been a useful tool for functional and morphological studies. ACK2, however, does not work on tissues fixed with paraformaldehyde, and not all ICC express c-Kit in human. Therefore, in order to find a new marker of ICC and/or new antibody resisting aldehyde fixation, we produced a new monoclonal antibody that identifies ICC and then investigated the properties of its antigen. Isolated ICC were used for immunization. Hybridomas fused with myeloma SP2 were screened by immunohistochemistry. ACK2 and each antibody were applied on serial sections, and the clone producing anti-ICC antibody (AIC) that stains ICC was established. The distribution of AIC immunopositive cells was examined in other organs and also GI muscles of W/Wv mice. The biochemical properties were studied using dot blot analysis. AIC recognized ICC; however, distribution of immunopositive cells in W/Wv mice and other organs was different from that of c-Kit. The immunoreactivity was stable for paraformaldehyde but was blocked by either Triton X-100 or SDS. In conclusion, new antibody AIC recognized ICC but the antigen was not c-Kit, which confirms the existence of good markers of ICC besides c-Kit. Although the antigen has not been isolated, AIC is suitable for morphological study and is useful for investigation of ICC in c-Kit mutants.

Animals↗
PubMed2004

The deficiency of immunoregulatory receptor PD-1 causes mild osteopetrosis.

Recently, the involvement of immune responses in metabolic bone disease and/or local bone destruction has received much attention. Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), a member of the immunoglobulin (Ig) superfamily, negatively regulates T cell activation. The deficiency of CTLA-4 induces profound osteopenia with an increase in osteoclastogenesis, suggesting the important role of activated T cells in osteoclastogenesis. Programmed death-1 (PD-1) is the newly identified immunoregulatory receptor, which also belongs to the Ig superfamily. Both CTLA-4 and PD-1 are induced on activated T cells, however, there are no reports linking PD-1 with osteoclasts. In the present study, we have examined the bone phenotype in PD-1-deficient mice PD-1-/- and the role of PD-1 in osteoclastogenesis and osteoclast function. Both trabecular and cortical bone mineral densities of tibia were significantly increased, as observed in peripheral quantitative computed tomography (pQCT), at 12 weeks of age in PD-1-/- mice. Histomorphometric analysis of the PD-1-/- mice and the age-matched controls at 12 weeks of age showed a 2-fold increase in bone volume (BV/TV) with a 55% decrease in osteoclast number (N.Oc/BS). Bone formation indices were similar in both groups. The number of soluble receptor activator of nuclear factor kappaB ligand (sRANKL)-induced osteoclast-like cells (OCLs) derived from the PD-1-deficient splenocytes was significantly decreased (by 25%). On the other hand, PD-1 deficiency did not affect the bone-resorbing activity of mature osteoclasts. Our results suggest that PD-1 deficiency reduces osteoclastogenesis resulting in an osteopetrotic phenotype. Identical members of the Ig superfamily, CTLA-4 and PD-1, which negatively regulate immune responses, may differentially affect osteoclastogenesis and bone remodeling.

Animals↗
PubMed2004

Increased incidence of acute graft-versus-host disease with the continuous infusion of cyclosporine A compared to twice-daily infusion.

We retrospectively compared the incidence of acute graft-versus-host disease (GVHD) before and after September 1999, when we changed the mode of cyclosporine A (CsA) administration from twice-daily infusions (TD) (n=58) to continuous infusion (CIF) (n=71). The incidence of grade II-IV acute GVHD in the CIF group (56%) was significantly higher than that in the TD group (27%, P=0.00022). Multivariate analysis identified only two independent significant risk factors for the development of grade II-IV acute GVHD; CIF of CsA (relative risk 2.59, 95% CI 1.46-4.60, P=0.0011) and the presence of HLA mismatch (2.01, 95% CI 1.15-3.53, P=0.014). The incidence of relapse was significantly lower in the CIF group when adjusted for disease status before transplantation (0.41, 95% CI 0.18-0.95, P=0.038), which resulted in better disease-free survival in high-risk patients (43 vs 16% at 2 years, P=0.039), but not in standard-risk patients (72 vs 80%, P=0.45). CIF of CsA with a target level of 250-400 ng/ml may not be appropriate for GVHD prophylaxis in standard-risk patients.

Acute Disease↗
PubMed2004

Cidofovir for treating adenoviral hemorrhagic cystitis in hematopoietic stem cell transplant recipients.

Adenovirus (AdV) infection is an important cause of morbidity and mortality in hematopoietic stem cell transplant (HSCT) recipients. We treated 16 patients with AdV hemorrhagic cystitis (HC) following HSCT with cidofovir (CDV; 1 mg/kg/day, three times weekly for 3 weeks). Patients included 10 males and six females with a median age of 50 years (range 10-62). Two of the 16 patients were unevaluable because of early death from nonadenoviral causes. CDV therapy cleared AdV from urine in 12 of 14 patients (86%). Of 14 patients, 10 (71%) showed clinical improvements in HC. Among 14 patients, seven (50%) had avoided renal damage, the most important CDV toxicity. One patient previously treated with foscarnet for cytomegalovirus (CMV) required hemodialysis, and CDV treatment was discontinued. In another patient, CDV treatment was discontinued because of grade 2 nephrotoxicity. Four patients became positive for CMV antigenemia while being treated with CDV, and two developed herpes simplex virus (HSV) stomatitis while being treated with CDV. CDV proved effective in treating AdV HC in transplant patients. However, CDV at 1 mg/kg/day given three times weekly failed to prevent breakthrough infection with CMV and HSV in some patients.

Adenoviridae↗
PubMed2004

Sweating responses during activation of the muscle metaboreflex in humans is altered by time of day.

AIM: The aim of the present study was to test for a time-of-day effect on sweating responses to activation of the muscle metaboreflex. METHODS: Eight male subjects each participated in two exercise sessions, one in the morning and one in the evening. Within each session there were two 60-s bouts of isometric handgrip (IHG) exercise at 50% maximal voluntary contraction. Prior to IHG, whole body warming by a water-perfused suit initiated mild sweating. The first bout of IHG exercise began at 06.00 hours (am) and 18.00 hours (pm). Blood circulation to the forearm was occluded for 120 s, beginning 5 s before the end of the second bout of IHG to activate the muscle metaboreflex. RESULTS: During both bouts of exercise, sweating rate (SR) on both the chest and right forearm significantly increased from the pre-exercise period in both am and pm sessions. SR rapidly decreased during first minute of recovery after the first bout of IHG exercise. However, during post-exercise ischaemia (PEI) after the second bout of IHG exercise, SR was maintained significantly above the pre-exercise level only in the pm session. The increases in SR on the chest and right forearm during PEI were significantly greater in the pm, than in the am, session. However, SR of the palm was not maintained during PEI. CONCLUSIONS: We conclude that under mild hyperthermic conditions, the sweating response in non-glabrous skin to activation of the muscle metaboreflex exhibits a time-of-day effect.

Adult↗
PubMed2004

Psychosocial predictors of successful delivery after unexplained recurrent spontaneous abortions: a cohort study.

OBJECTIVE: To examine psychosocial predictors of successful pregnancy after recurrent spontaneous abortions (RSA). METHOD: We administered two waves of semi-structured interview and self-report questionnaire battery to a consecutive series of 46 couples who had had two RSAs (baseline before third pregnancy, and immediately after third pregnancy was ascertained), and followed them through their third pregnancy. RESULTS: Of the 46 couples, four miscarried for karyotypal abnormalities and six without any known cause. When the latter six were compared with the remaining 36 women, they reported less social support satisfaction, a more stable attribution for the causes of past abortions, and more depressed mood in the preceding year. Taken altogether, this psychosocial model was able to predict 93% of the pregnancy outcomes correctly. CONCLUSION: Psychosocial variables (depression, attribution and social support) are robust predictors of the prospective pregnancy and suggest possible points of intervention in couples with RSA.

Abortion, Spontaneous↗
PubMed2004

Activation of nuclear factor-kappa B in the conjunctiva with the epithelial scraping of the mouse cornea and human epidemic keratoconjunctivitis.

AIM: To examine the expression of p65, one of nuclear factor-kappa B (NF-kappa B), in the conjunctival epithelium of the C57Bl6 mouse and a patient with epidemic keratoconjunctivitis (EKC). METHODS: Normal and epithelial scraped cornea obtained 6 hours after the injury were processed for paraffin section. Samples of a normal and an EKC conjunctival epithelium were obtained using impression cytology. Both samples were analysed by immunocytochemistry using anti-p65 antibody. RESULTS: Immunocytochemistry with the anti-NF-kappa B p65 antibody revealed that p65 was localised in the cytoplasm of the conjunctival epithelium in the C57Bl6 mouse without the treatment. Six hours after the scraping of the cornea, p65 protein was expressed in the nuclei of the conjunctival epithelium. p65 was localised in the cytoplasm of the conjunctival epithelium in the human normal eye. p65 protein was expressed in the nuclei of the conjunctival epithelial cells in the EKC patient. CONCLUSION: These findings suggest that NF-kappa B was activated in the conjunctiva in the epithelial scraping of the mouse cornea and in human EKC.

Animals↗
PubMed2004

A new scoring system for Perthes' disease based on combined lateral and posterior pillar classifications.

We have devised a combined pillar score (CPS) system, based on the lateral pillar (LP) and the posterior pillar (PP) classifications, together with the age at onset of Perthes' disease, and examined its correlation with prognosis. The correlation coefficient of the Catterall classification, LP, PP, and CPS systems with the Stulberg system was 0.39, 0.52, 0.50, and 0.70, respectively. Overall 21 of the 22 hips (95.4%) with a CPS of 0 to 1 point had a good outcome and 12 of the 13 hips (92.3%) with a CPS of 3 points or more had a fair or poor outcome. None with a CPS of 2 points, had a poor outcome. The study shows that an accurate prediction of the prognosis is not possible with the LP classification alone for patients classified as belonging to group B (LP height 50% to 100% of contralateral height). The CPS system does allow accurate prediction of outcome.

Age of Onset↗
PubMed2004

[Surgical treatment of pulmonary metastases from colon and rectal cancer].

We retrospectively studied the surgical treatment for pulmonary metastases from colon and rectal cancer. A total of 24 patients (9 males and 15 females; mean age 61 years) underwent 29 thoracotomies for metastatic colon carcinoma, while 22 patients (16 males and 6 females; mean age 63 years) underwent 29 thoracotomies for metastatic rectal cancer. The median interval between the primary procedure and lung resection for metastases was 26 months in the patients with colon carcinoma and 32 months in the patients with rectal cancer. In the patients with colon carcinoma, 16 underwent wedge resection or segmentectomy (including 4 video-assisted procedures) and 13 (54%) underwent lobectomy or pneumonectomy. In the patients with rectal cancer, 15 underwent wedge or segmentectomy (including 1 video-assisted procedure), 13 (59%) underwent lobectomy or pneumonectomy, and 1 underwent exploratory thoracotomy. All procedures except exploratory thoracotomy were curative operations. There was no mortality. Overall 5-year survival was 56% (n=46). Five-year survival was 65% for patients with colon metastases (n=24) and 45% for patients with rectal metastases (n=22), and there was no significant difference. Recurrent sites were 4 lungs (36%), 4 livers (36%), 1 bone, 1 uterus, and 1 peritoneum in patients with colon carcimoma, and 10 lungs (43%), 5 brains (22%), 3 livers (13%), 1 bone, and 1 vagina in patients with rectal cancer. Pulmonary resection for metastases from colon carcinoma may have better prognosis than that from rectal cancer. However, further investigation may be required to obtain convincing conclusions.

Adult↗
PubMed2004

[Observation of the right atrial wall suture line after tricuspid valve supra-annular implantation].

Strength of the right atrial wall suture line after tricuspid valve supra-annular implantation (TVSI) is controversial. We observed the right atrial supra-annular position of a 63-year-old male during his third mitral operation who underwent mitral valve replacement (MVR) and TVSI 15 years ago. Eight years later, he received the second MVR and removal of the bioprosthetic valve from the tricuspid position due to primary tissue failures. The annular size of the tricuspid valve had decreased enough to be fixed by tricuspid annuloplasty (TAP) and re-TVSI was not needed at that time. In this operation, 7 years following bioprosthetic valve removal, the circularly bulging atrial wall still remained and seemed to have enough strength for holding the prosthetic valve. This finding may support the conclusion that the right atrial wall has enouth strength for holding a prosthetic valve in position.

Bioprosthesis↗
PubMed2003

Absence of suppression in particle production at large transverse momentum in sqrt[s(NN)]=200 GeV d+Au collisions.

Transverse momentum spectra of charged hadrons with p(T)<8 GeV/c and neutral pions with p(T)<10 GeV/c have been measured at midrapidity by the PHENIX experiment at BNL RHIC in d+Au collisions at sqrt[s(NN)]=200 GeV. The measured yields are compared to those in p+p collisions at the same sqrt[s(NN)] scaled up by the number of underlying nucleon-nucleon collisions in d+Au. The yield ratio does not show the suppression observed in central Au+Au collisions at RHIC. Instead, there is a small enhancement in the yield of high momentum particles.

Journal Article↗
PubMed2003

Dissociation between the circadian rhythm of locomotor activity and the pineal clock in the Japanese newt.

The circadian locomotor activity rhythm of the Japanese newt has been thought to be driven by a putative brain oscillator(s) subordinate to the pineal clock. The existence of mutual coupling between the pineal clock and the brain oscillator(s) in vivo was examined. We covered the newt's skull with aluminum foil and simultaneously reversed the light-dark cycle, thereby allowing the pineal organ to be exposed to constant darkness while the rest of the animal was exposed to the reversed light-dark cycle. In control animals, whose heads were covered with transparent plastic, the rhythm of synaptic ribbon number in the pineal photoreceptor cells was entrained to the reversed light-dark cycle. Rhythms from newts whose heads were shielded, however, were similar to those observed in the unoperated newts kept under constant darkness. The locomotor activity rhythms of both head-covered animals and control animals were entrained to the reversed light-dark cycle. These data suggest that extrapineal photoreception can entrain the putative brain oscillator(s), but not the pineal clock. Thus, at least in an aspect of photic entrainment, there seems to be little or no mutual coupling between the pineal clock and the putative brain oscillator(s) in the circadian system of the Japanese newt.

Animals↗
PubMed2003

Implication of brain-derived neurotrophic factor in the release of dopamine and dopamine-related behaviors induced by methamphetamine.

It is widely recognized that methamphetamine enhances the release of dopamine at dopaminergic neuron terminals of the mesolimbic system, which induces dopamine-related behaviors. Brain-derived neurotrophic factor (BDNF), a neurotrophin, binds to and activates its specific receptor tyrosine kinase, TrkB. BDNF has been shown to influence the release of dopamine in the mesolimbic dopamine system. The present study was designed to investigate roles of BDNF and TrkB in the expression of methamphetamine-induced dopamine release in the nucleus accumbens and dopamine-related behaviors induced by methamphetamine in rats. Methamphetamine (1 mg/kg, s.c.) produced a substantial increase in the extracellular levels of dopamine and induced a progressive augmentation of dopamine-related behaviors such as rearing and sniffing. In contrast, both the stimulation of dopamine release and induction of dopamine-related behaviors by methamphetamine were significantly suppressed by pretreatment with intra-nucleus accumbens injection of either BDNF (2.0 microl/rat, 1:1000, 1:300 and 1:100) or TrkB (2.0 microl/rat, 1:1000 and 1:100) antibody. Furthermore, the basal level of dopamine in the nucleus accumbens was not affected by treatment with both BDNF and TrkB antibodies. These findings provide further evidence that BDNF/TrkB pathway is implicated in the methamphetamine-induced release of dopamine and the induction of dopamine-related behaviors.

Amphetamine-Related Disorders↗