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Biomedical subjects

K Hirata

Publications and source records attributed to K Hirata.

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

Acute improvement of atrial mechanical stunning after electrical cardioversion of persistent atrial fibrillation: comparison between biatrial and single atrial pacing.

OBJECTIVE: To evaluate the acute effects of atrial pacing at different pacing sites on mechanical stunning after cardioversion of atrial fibrillation (AF). SETTING: Tertiary referral centre. PATIENTS: 20 patients with persistent AF were studied. INTERVENTIONS: Spontaneous echo contrast (SEC), left atrial appendage emptying velocity (LAAEV), and left atrial appendage emptying fraction (LAAEF) were assessed by transoesophageal echocardiography (TOE) during AF, after conversion to sinus rhythm, and during atrial pacing from the right atrial appendage, left lateral atrium, and both atria simultaneously. Transmitral inflow velocity of the atrial wave (TMIF-A) by TOE and the maximum P wave duration in 12 lead ECG were also measured during sinus rhythm and atrial pacing. MAIN OUTCOME MEASURES: Comparison of atrial mechanical function and P wave duration in 12 lead ECG during atrial pacing from different sites after cardioversion of AF. RESULTS: Compared with sinus rhythm, atrial pacing at 80 beats/min increased LAAEV from mean (SD) 14.6 (10.1) to 33.4 (19.8) cm/s (p = 0.001), LAAEF from 13.8 (8.5) to 32.1 (11.2)% (p < 0.001), and TMIF-A from 24.6 (11.9) to 45.6 (21.0) cm/s (p < 0.001) and reduced SEC grade from 2.6 (1.0) to 1.6 (0.9) (p < 0.001). These effects had a positive force-frequency relation. Biatrial pacing produced the shortest P wave duration and resulted in the most significant improvement in atrial function (LAAEV, 33.2 (19.3) v 53.7 (23.9) cm/s, p = 0.0001; LAAEF, 31.9 (11.1) v 46.2 (12.6)%, p < 0.0001; TMIF-A, 37.7 (18.3) v 54.1 (21.2) cm/s, p < 0.001; SEC grade, 1.4 (1.1) v 0.8 (0.9), p = 0.001, right atrial appendage versus biatrial pacing). CONCLUSIONS: Atrial pacing at increased rates can improve atrial mechanical function after cardioversion of persistent AF. Biatrial pacing may be the most effective technique to reverse atrial mechanical stunning.

Adolescent↗
PubMed2005

Intractable chronic inflammatory demyelinating polyneuropathy treated successfully with ciclosporin.

BACKGROUND: Chronic inflammatory demyelinating polyneuropathy (CIDP) is a heterogeneous disorder and both clinical course and response to treatment vary widely. Because of the propensity for relapse, CIDP requires maintenance therapy after the initial response to treatment. There is no consensus regarding this in the published literature. PRESENT REPORT: A patient with CIDP was treated with oral prednisolone and cyclophosphamide pulse therapy but required repeated plasma exchange and intravenous immunoglobulin (IVIg). Treatment with ciclosporin freed the patient from repeated IVIg administration. Therapeutic responses in 14 subsequent cases including three patients who showed improvement with ciclosporin are also presented along with an algorithm of the authors' suggested protocol for treatment. CONCLUSION: Ciclosporin should be considered for patients with intractable CIDP who require repeated IVIg.

Administration, Oral↗
PubMed2005

Ambiguous value of Haemophilus influenzae isolation in Guillain-Barre and Fisher syndromes.

BACKGROUND: Haemophilus influenzae is considered a causative agent of Guillain-Barré syndrome (GBS) and Fisher syndrome, but the frequency of this infection in GBS is controversial. OBJECTIVE: To determine whether isolation of H influenzae indicates it is a causative agent in GBS and Fisher syndrome. RESULTS: Four (15%) of 27 patients with GBS and Fisher syndrome in whom H influenzae was isolated were also seropositive for Campylobacter jejuni. Antiganglioside IgG antibodies in these four patients did not cross react with their H influenzae lipo-oligosaccharides, whereas antiganglioside antibodies in the four patients with positive serology for H influenzae did. CONCLUSIONS: The findings suggest that H influenzae isolation is not always indicative of the causative agent in these syndromes and that tests for other infections should be made, even in cases of positive culture.

Adult↗
PubMed2005

In vivo assessment of the cutaneous bioavailability of topically applied maxacalcitol.

Maxacalcitol (22-oxacalcitriol), a vitamin D3 analogue, is widely used for the treatment of psoriasis. The effects of topical dermatologic drugs have been assessed by their pharmacodynamic activities, and concentrations in the skin correlate with these activities. In this study, we assessed the cutaneous bioavailability of topically applied maxacalcitol ointment in vivo by tape stripping. Six drug application sites were randomly assigned on the left volar forearm of six healthy men. Fifty milligrams of maxacalcitol ointment (25 microg/g) was applied to each site. After 0 (15 s), 0.5, 1, 2, 4, or 6 h, the ointment was gently removed, and tape stripping was performed. Maxacalcitol was extracted from the tape strips and quantified by liquid chromatographic tandem mass spectrometry. Average concentrations of maxacalcitol in the stratum corneum (SC) were 2.61, 4.37, 6.23, 9.37, and 9.46 microg/g at 0.5, 1, 2, 4, and 6 h, respectively, after drug application. The steady state was attained approx. 4 h after drug application. The cutaneous bioavailability of topical maxacalcitol ointment can be assessed by the tape-stripping method. This approach will probably be useful in the assessment of the bioequivalence of topical dermatologic products and as a parameter for pharmacokinetic/pharmacodynamic studies.

Adhesives↗
PubMed2005

[Surgical treatment of lung cancer in octagenarian patient].

Because average life span of Japanese is getting longer, we sometimes meet elder lung cancer patients of over 80. They often have many complications, so we are worried about how to treat them. Recently we met 8 elder patients with lung cancer, and we performed surgical operation for them. Six patients performed partial lung resection or lobectomy had no complications after operation. But 2 patients with respiratory disorder who performed lobectomy and chest wall resection had some complications after operation. In such patients, careful postoperative management is needed, and continuous positive airway pressure (CPAP) ventilation with pressure support (PS) may be useful to prevent respiratory complications.

Age Factors↗
PubMed2005

[Left coronary ostial stenosis caused by syphilitic aortitis].

We report 2 cases of cardiovascular disease related to end-stage syphilitic infection, which is now relatively rare. A 49-year-old man (case 1), and a 45-year-old man (case 2) were admitted to our hospital for angina pectoris. Cardiac catheterization showed severe aortic regurgitation and left coronary ostial stenosis. Active syphilis was detected in both cases by routine blood examination on admission. Oral ampicillin was started immediately to treat the syphilis; however, during the course of treatment, acute heart failure developed in both patients. We performed emergency aortic valve replacement and coronary artery bypass grafting. Intraoperatively, the orifice of the left coronary artery was almost occluded, and retrograde perfusion of cardioplegia was needed to induce cardiac arrest. Both patients recovered uneventfully. When treating patients with antibiotics for syphilitic disease, it is important to prepare for the possibility of urgent surgery.

Coronary Stenosis↗
PubMed2005

The interplay between gastric cancer cell lines and PBMCs mediated by the CC chemokine RANTES plays an important role in tumor progression.

In the present study, we investigated the effect of the RANTES-mediated interaction between gastric carcinoma cell lines and peripheral blood mononuclear cells (PBMCs) in tumor progression. RANTES production in PBMCs stimulated by highly metastatic cancer cell line-conditioned supernatants was higher than in those stimulated by a less metastatic gastric cancer cell line-conditioned supernatant. RANTES receptors were expressed in PBMCs, but not in those cancer cell lines; therefore it was suggested that RANTES might affect PBMCs but not cancer cells. Matrix metalloproteinase (MMP)-9 expression in PBMCs was examined. Similar to RANTES production, MMP-9 expression in PBMCs stimulated by highly metastatic cell line-conditioned supernatants was higher than in that stimulated by a less metastatic cell line-conditioned supernatant. Invasion assays of gastric cancer cell lines were performed. Cancer cells cultured with PBMCs invaded into Matrigel more frequently than those without PBMCs. This invasive activity was highly inhibited by an anti-RANTES antibody. These results suggest that tumor cells can acquire the potential for invasion by cooperating with PBMCs and RANTES plays an important role in the interplay between tumor cells and PBMCs. It is thus thought that RANTES might be a candidate molecular target in the therapeutic strategy for gastric cancers.

Base Sequence↗
PubMed2004

Superconductivity in the metal rich Li-Pd-B ternary boride.

Superconductivity at about 8 K was observed in the metal-rich Li-Pd-B ternary system. Structural, microstructural, electrical, and magnetic investigations for various compositions proved that the Li2Pd3B compound, which has an antiperovskite cubic structure composed of distorted Pd6B octahedrons, is responsible for the superconductivity. This is the first observation of superconductivity in metal-rich ternary borides containing alkaline metal and Pd as a late transition metal. The compound prepared by arc melting has a high density and is relatively stable in the air. The upper critical fields H(c2)(0) estimated by linear extrapolation and the Werthamer-Helfand-Hohenberg theory are 6.2 and 4.8 T, respectively.

Journal Article↗
PubMed2004

Immunoglobulin improves a model of acute motor axonal neuropathy by preventing axonal degeneration.

BACKGROUND: The action mechanism of IV immunoglobulin (IVIg) for Guillain-Barré syndrome has yet to be clarified. OBJECTIVE: To evaluate clinical, histologic, and immunologic effects in a disease model of acute motor axonal neuropathy (AMAN) treated by IVIg. METHODS: Rabbits were sensitized with gangliosides including GM1 and divided randomly into two groups at disease onset. One group received IV homologous gamma-globulin (400 mg/kg/day) for 5 days (n = 15), and the other received saline (n = 15). Disease severity was scored (0 to 13 points) daily. Sixty days after onset, anti-GM1 antibodies were tested by ELISA, and the number of degenerative axons was counted in spinal anterior roots. RESULTS: Between both groups at onset, there was no difference in any characteristics including clinical score. The IVIg group had faster recovery than the saline group (p = 0.03). The percentage of rabbits that improved by a score of < or =4 was higher in the IVIg (53%) than in the saline (13%) group 60 days after onset (p = 0.03). Anti-GM1 IgG titers 60 days after onset did not differ between the groups. The anterior roots of rabbits surviving 60 days after onset showed lower frequency of axonal degeneration in the IVIg-treated (n = 11; mean 4.5%) than in the saline-treated (n = 8; mean 11.1%) rabbits (p = 0.01). CONCLUSIONS: The therapeutic efficacy of IVIg in an AMAN model was confirmed. IVIg may not affect the production or catabolism of anti-GM1 IgG, but it may prevent axonal degeneration of motor nerves.

Animals↗
PubMed2004

Acute motor axonal neuropathy after Mycoplasma infection: Evidence of molecular mimicry.

BACKGROUND: Patients with Guillain-Barré syndrome (GBS) after Mycoplasma pneumoniae infection often have antibodies to galactocerebroside (GalC). Electrodiagnosis may show acute inflammatory demyelinating polyneuropathy (AIDP). METHODS: The authors report a patient with acute motor axonal neuropathy (AMAN) after Mycoplasma infection and review seven cases of Mycoplasma-associated GBS. They investigated anti-GalC serology under various conditions associated with Mycoplasma infection. RESULTS: The patient had immunoglobulin (Ig)G and IgM antibodies against GM1 and GalC, which cross-reacted. During the acute phase, IgM selectively immunostained axons. The cholera toxin B-subunit and rabbit anti-GM1 IgG stained a band in the lipid extract from M pneumoniae, indicative of the presence of a GM1 epitope. Six Mycoplasma-associated GBS patients with anti-GalC antibodies had non-AIDP electrodiagnoses, whereas one with Mycoplasma-associated AIDP had no anti-GalC antibodies. Anti-GalC antibodies were positive in two of five patients who had neurologic diseases other than GBS after Mycoplasma infection and in one of 12 who had acute respiratory disease caused by M pneumoniae not followed by a neurologic disease. CONCLUSIONS: Anti-GalC antibodies in Mycoplasma-associated GBS may be an epiphenomenon. In certain cases, anti-GM1 antibodies induced by molecular mimicry with M pneumoniae may cause acute motor axonal neuropathy.

Acute Disease↗
PubMed2004

Phase I/II study of cisplatin combined with weekly paclitaxel in patients with advanced non-small-cell lung cancer.

To determine the maximum-tolerated dose (MTD) and the recommended dose (RD) of paclitaxel administered weekly with a fixed dose of cisplatin, and to assess the toxicity and activity of this combination, we conducted a phase I/II trial in patients with advanced non-small-cell lung cancer (NSCLC). In this study, patients with stage IIIB/IV NSCLC were eligible. Paclitaxel, at a starting dose of 40 mg x m(-2) week(-1) on days 1, 8, and 15, was combined with a fixed dose of cisplatin 80 mg x m(-2) on day 1. Chemotherapy was given in a 4-week cycle. In this phase I/II study, 38 patients were enrolled. Dose-limiting toxicities (DLT) were neutropenia, fatigue, and omission of treatment due to leucopenia, thrombocytopenia, or febrile neutropenia. The MTD and RD were estimated to be 70 mg x m(-2). Of the 37 assessable patients, 23 had a partial response and one had a complete response. Overall response rate was 62.1% (95% confidence interval (CI): 46.5-77.7%). The progression-free survival, the median survival time, and the 1-year survival rate were 5.5 months, 13.7 months, and 56.9%, respectively. This regimen is tolerable and very active against advanced NSCLC, and its efficacy should be confirmed in a phase III study.

Adult↗
PubMed2004

Acute facial diplegia and hyperreflexia: A Guillain-Barré syndrome variant.

Two patients with acute facial diplegia and hyperreflexia are described. Both patients had serologic evidence of preceding Campylobacter jejuni infection and antiganglioside IgG antibodies as well as other laboratory and electrophysiologic findings suggesting Guillain-Barré syndrome (GBS). IV immunoglobulin produced recovery. Hyperreflexia does not necessarily exclude the diagnosis of a GBS variant. Antiganglioside antibodies can help with diagnosis in difficult cases.

Acute Disease↗
PubMed2004

Isolation and characterization of a mesenchymal cell line that differentiates into osteoblasts in response to BMP-2 from calvariae of GFP transgenic mice.

We established the clonal mesenchymal cell line, GFP-C3 (C3), which differentiates into osteoblasts in response to BMP-2 from calvariae of newborn green fluorescence protein (GFP) transgenic mice. This cell line cultured with control medium expressed low levels of alkaline phosphatase (ALP) activity and osterix mRNA and undetectable ALP and osteocalcin mRNA. Incubation of these cells with rhBMP-2 increased ALP activity dose-dependently and induced substantial levels of ALP, osteocalcin and osterix mRNA expression. C3 cells infected with adenovirus vector encoding BMP-2 (AdBMP-2) or Runx2 (AdRunx2) showed greatly increased ALP mRNA expression in a time-dependent fashion. Transduction with AdRunx2-induced expression of ALP and osteocalcin mRNA, but not osterix mRNA by day 3. Transduction with AdBMP-2 induced apparent expression of ALP and osterix mRNA by day 1 after transduction, but induced only weak expression of osteocalcin mRNA day 3 after transduction. Transplantation of C3 cells transduced with AdBMP-2 into back subfascia in wild-type mice with a complex of poly-d,l-lactic-co-glycolic acid/gelatin sponge (PGS) generated ectopic bone formation involving GFP-positive osteoblasts and osteocytes 2 weeks after transplantation. C3 cells transduced with AdRunx2 or AdLacZ failed to induce ectopic bone formation. Transplantation of C3 cells transduced with AdBMP-2 into craniotomy defects in wild-type mice using PGS as a carrier induced bone formation 2 weeks after transplantation, and replaced defects 4 weeks after transplantation. C3 cells transduced with AdRunx2 failed to induce bone repair after transplantation into craniotomy defects. These results indicate that C3 cells retain differentiation potential into osteoblasts in response to BMP-2. They are useful tools for analyzing the process of osteoblast differentiation in vivo after transplantation.

Animals↗
PubMed2004

Usefulness of anti-GQ1b IgG antibody testing in Fisher syndrome compared with cerebrospinal fluid examination.

Fisher syndrome (FS), a variant of Guillain-Barré syndrome (GBS), is a rare disorder, and there are few reported studies of a large number of patients with FS. Cerebrospinal fluid (CSF) albuminocytological dissociation was found in 59% of 123 FS patients during the first 3 weeks of illness, while serum anti-GQ1b IgG antibody was positive in 85%. Whereas the incidence of CSF albuminocytological dissociation increased from the first to second weeks in FS, anti-GQ1b IgG antibody peaked in the first week, but there was no CSF albuminocytological dissociation. Statistically, anti-GQ1b antibody testing was superior to a CSF examination in supporting a diagnosis of FS during the first 3 weeks of illness, especially in the first week.

Adolescent↗
PubMed2004

Synthetic sulfonolipids deduced from sulfonoquinovosyl diacylglycerols of sea urchin reduces hepatic ischemia-reperfusion injury in rats.

BACKGROUND: In hepatic surgery and liver transplantation, ischemia-reperfusion (I/R) is an unavoidable process, and protection against hepatic I/R injury is a major unresolved problem. In this study, we investigated whether 3-O-(6-deoxy-6-sulfono-beta-D-glucopyranosyl)-1,2-di-O-acylglycerol bound to saturated C18 fatty acids (beta-SQAG9), which was derived from sea urchin intestines, could reduce this injury. This agent was recently reported to have immunosuppressive effects in allogeneic rat skin grafts. MATERIALS & METHODS: Male Lewis rats were divided into two experimental groups. Group 1 rats were injected with SQAG9 (50 mg/kg) into the penile vein 15 minutes before the induction of ischemia and into the portal vein just reperfusion. The same amounts of normal saline were injected into rats in the control group (group 2). Each experimental groups included six rats. Seventy percent hepatic ischemia (20 minutes) was induced by occluding the blood vessels and bile duct with a vascular clamp. For examination of hepatic function, serum levels of aspartate aminotransferase, (AST) alanine transaminase (ALT), and lactic dehydrogenase (LDH) were measured. In addition, histological examination was also assessed. RESULTS: Three hours after reperfusion, the mean plasma concentration of AST, ALT, LDH in group 1 was suppressed compared with group 2. Six hours after reperfusion, the hepatic damage in group 1 was mild in comparison with that in group 2. CONCLUSIONS: Our data demonstrated that SQAG-9 reduced the warm hepatic I/R injury.

Animals↗
PubMed2004

Circadian rhythm of melatonin release from the photoreceptive pineal organ of a teleost, ayu (Plecoglossus altivelis) in flow-thorough culture.

In the present study, we tested whether the pineal organ of ayu (Plecoglossus altivelis), an osmerid teleost close relative of salmonids, harbours a circadian oscillator regulating rhythmic melatonin release using flow-through culture. The pineal organ maintained under light/dark cycles released melatonin in a rhythmic fashion with high levels during the dark phase. A circadian rhythm of melatonin release persisted in constant darkness for at least four cycles. Characteristics of the circadian rhythm (free-running period, phase and amplitude) exhibited small variations among cultures when the data was normalized, indicating that this system is sufficient for the analysis of the circadian rhythm both at qualitative and quantitative levels. Six-hour extension of the light phase from the normal onset time of the dark phase or exposure to constant light for 36 or 48 h before transfer to constant darkness significantly inhibited melatonin release. Phase shifts in the circadian rhythm of melatonin release were also observed. Thus, the ayu pineal organ contains all the three essential components of the circadian system (a circadian clock, the photoreceptor responsible for photic entrainment of the clock, and melatonin generating system as an output pathway). This system should provide a useful model for analysing the physiological and molecular basis of the vertebrate circadian system. In addition, further comparative studies using salmonids and related species including ayu will provide some insight into the evolution of the roles of the pineal organ in the vertebrate circadian system.

Animals↗
PubMed2004

Profiling analysis of differential gene expression between hematogenous and peritoneal metastatic sublines of human pancreatic cancer using a DNA chip.

We established the novel sublines HPC-1H5, HPC-3H4, HPC-4H4, and Panc-1H5, which have a high potential of liver metastasis, and HPC-1P5a, HPC-3P4a, HPC-4P4a, and Panc-1P5a, which have a high potential of peritoneal dissemination, derived from low metastatic HPC-1, HPC-3, HPC-4, and Panc-1cell lines, respectively. To clarify the molecular mechanisms of cancer metastasis and of the different levels of gene expression in a variety of metastatic potentials in pancreatic cancer, we performed a broad analysis of differential gene expression analysis between parental cell lines and metastatic sublines. In comparison with the parental cell lines, 65 and 36 genes were overexpressed and underexpressed in highly liver-metastatic sublines. On the other hand, 43 and 45 genes were overexpressed and underexpressed in highly peritoneal-metastatic sublines. uPAR and Serin protease were overexpressed, and E2A and IGF1R were underexpressed in both metastatic sublines. Hierarchical clustering analysis revealed 22 genes classifying liver, peritoneal metastatic sublines and low-metastatic parental cell lines. These genes might be targeted genes separating those two major metastatic forms after surgery. A greater number of cell line samples and more genes will have to be utilized in future studies in order to understand the involvement of genes in cancer metastasis more thoroughly. However, these results will help to clarify the molecular mechanisms of pancreatic cancer metastasis.

Cell Line, Tumor↗