Biomedical subjects

M Yoshida

Publications and source records attributed to M Yoshida.

At least 73 records · Page 4Linked to original sources

PubMed2004

Calcium/calmodulin kinase IV pathway is involved in the transcriptional regulation of the corticotropin-releasing hormone gene promoter in neuronal cells.

Although corticotropin-releasing hormone (CRH) plays a pivotal role in the regulation of the hypothalamo-pituitary-adrenal axis, the mechanism of CRH gene expression in the neuronal cell is not completely understood. In this study, we examined the transcriptional regulation of human CRH gene 5'-promoter, using a human BE(2)C neuroblastoma cell line expressing intrinsic CRH. In particular, we focused on the involvement of calmodulin kinases (CaMKs), which are known to play an important role in excitation-induced gene expression through the rise in intracellular calcium in the central nervous system. RT-PCR analysis confirmed the expression of CaMK as well as CRH mRNA in BE(2)C cells. When we introduced approximately 1.1 kb of the 5'-promoter region of the human CRH fused with luciferase reporter gene into the cells, a substantial transcriptional activity was observed, and this was further increased by the activation of the cAMP/PKA pathway. We then examined the effect of activation of CaMKs by introducing the expression vectors of each kinase, revealing a potent stimulatory effect of CaMKIV, but no effect of CaMKII. Depolarization of the cells caused an increase in CRH promoter activity, which was completely abolished by the treatment with the CaMK antagonist K252a. Interestingly, KCREB, a dominant negative form of CREB, antagonized the effect of the CaMKIV-mediated effect. Altogether, we conclude that not only the cAMP/PKA but also the calcium/CaMKIV signaling pathway is involved in the regulation of CRH gene expression. Furthermore, CREB is thought to be involved in CaMK- as well as cAMP/PKA-mediated CRH gene expression. Since the CRH gene is expressed in the neuronal cells of the hypothalamus, the calcium/CaMKIV signaling pathway may play an important role in the excitation-mediated regulation of CRH synthesis.

Calcium↗

PubMed2004

Microbial counts, fermentation products, and aerobic stability of whole crop corn and a total mixed ration ensiled with and without inoculation of Lactobacillus casei or Lactobacillus buchneri.

Whole crop corn (DM 29.2%) and a total mixed ration (TMR, DM 56.8%) containing wet brewers grains, alfalfa hay, dried beet pulp, cracked corn, soybean meal, and molasses at a ratio of 5:1:1:1:1:1 on fresh weight basis, were ensiled with and without Lactobacillus casei or Lactobacillus buchneri in laboratory silos. The effects of inoculation on microbial counts, fermentation products, and aerobic stability were determined after 10 and 60 d. Untreated corn silage was well preserved with high lactic acid content, whereas large numbers of remaining yeasts resulted in low stability on exposure to air. Inoculation with L. casei suppressed heterolactic fermentation, but no improvements were found in aerobic stability. The addition of L. buchneri markedly enhanced the aerobic stability, while not affecting the DM loss and NH3-N production. Large amounts of ethanol were found when the TMR was ensiled, and the content of ethanol overwhelmed that of lactic acid in untreated silage. This fermentation was related to high yeast populations and accounted for a large loss of DM found in the initial 10 d. The ethanol production decreased when inoculated with L. casei and L. buchneri, but the effects diminished at 60 d of ensiling. Inoculation with L. buchneri lowered the yeasts in TMR silage from the beginning of storage; however, the populations decreased to undetectable levels when stored for 60 d, regardless of inoculation. No heating was observed in TMR silage during aerobic deterioration test for 7 d. This stability was achieved even when a high population of yeasts remained and was not affected by either inoculation or ensiling period. The results indicate that inoculation with L. buchneri can inhibit yeast growth and improve aerobic stability of corn and TMR silage; however, high stability of TMR silage can be obtained even when no treatments were made and high population (>10(5) cfu/g) of yeasts were detected.

Aerobiosis↗

PubMed2004

Concentration of clarithromycin and 14-R-hydroxy-clarithromycin in plasma of patients with Mycobacterium avium complex infection, before and after the addition of rifampicin.

Clarithromycin (CAM) and rifampicin (RFP) have both been recognized to be effective antibiotic agents against Mycobacterium avium complex (MAC) infection. Rifamycin derivatives including RFP and rifabutin modulate the CAM metabolism by inducing the hepatic cytochrome p-450 3A4. To clarify the effect of RFP on the CAM metabolism, we measured the plasma concentration of CAM and 14-R-hydroxyclarithromycin (M-5), the major metabolite of CAM, in 9 patients suffering from MAC infection before and after the addition of RFP. After the addition of RFP, the mean plasma concentration of CAM significantly decreased, while that of M-5 did not. In addition, the amount of CAM + M-5 concentration also significantly decreased. As M-5 is less effective against MAC infection than CAM, more attention should thus be paid to the plasma CAM concentration in patients administered CAM and RFP concomitantly.

Aged↗

PubMed2004

Utilization of sludge in building material.

Several thermal solidification processes have been developed mainly in Japan. They are lightweight aggregates, brick, interlocking tile, char, and slag. A full-scale plant of them has been successfully operated for more than 10 years. The quality of the end products is better than the traditional ones. They are all substitutive to existing ones. The Japanese experience proves that all the processes are technically feasible, but not economically. Their manufacturing cost is always higher than market price. In addition, they consume large amounts of energy. However, if they are identified for a process of sludge disposal, all of them are worth considering for a big city where there is no place for the sludge to go. The end products can be reused inside the city. A new alternative is "Portland cement". A Portland cement manufacturer accepts sewage sludge, if being paid some amount of money. An average payment is US$100 each 1,000 kg of ash or sludge cake. The Portland cement manufacturer accepts either cake or ash at the same price. It is about 50 to 30% of the energy cost of thermal solidification. The question is which is the better, dewatered cake or incinerated ash, for the Portland cement application. The answer is "it depends on the distance between the sewage plant and the Portland cement plant."

Calcium Compounds↗

PubMed2004

Interactions between pulmonary surfactant and alveolar macrophages in the pathogenesis of lung disease.

This article reviews recent findings regarding interrelationships between the pulmonary surfactant system and alveolar macrophages in the pathogenesis of human lung diseases, including pulmonary alveolar proteinosis, pulmonary infection, inflammation and obstructive lung diseases. Various components of pulmonary surfactant interact with alveolar macrophages in the modulation of innate host defense responses of the lung. In a reciprocal manner, alveolar macrophages regulate surfactant homeostasis, influencing rates of surfactant protein and phospholipid clearance and catabolism. Increasing evidence suggests that the complex interactions between the surfactant system and the alveolar macrophage are intrinsically linked to development of various lung diseases.

Animals↗

PubMed2003

Equation-of-state measurements of polyimide at pressures up to 5.8 TPa using low-density foam with laser-driven shock waves.

The laser-driven equation-of-state (EOS) experiments for polyimide are presented. The experiments were performed with emission measurements from the rear sides of shocked targets at up to a laser intensity of 10(14) W/cm(2) or higher with 351 nm wavelength and 2.5 ns duration. Polyimide Hugoniot data were obtained up to 0.6 TPa with good accuracy. Applying low-density foam ablator to the EOS unknown material, we also obtained the data at a highest pressure of 5.8 TPa in the nonmetal materials. Those data were in agreement with the theoretical curves.

Journal Article↗

PubMed2003

MRI in methotrexate-related leukoencephalopathy: Disseminated necrotising leukoencephalopathy in comparison with mild leukoencephalopathy.

We report two fatal cases of methotrexate (MTX)-induced disseminated necrotising leukoencephalopathy (DNL) in which MRI was repeated from the onset. Initial T2-weighted images showed multiple areas of high signal, mainly in deep cerebral white matter, which on follow-up, spread and coalesced to involve the entire white matter. Small irregular low-signal foci on T2-weighted images were seen within the high-signal lesions. Multiple areas of contrast enhancement corresponded to these low-signal foci. The condition of both patients deteriorated and they died. We compared their MRI findings with those of seven patients with mild MTX-related leukoencephalopathy, six of whom were asymptomatic; one had transient neurological symptoms. They showed no contrast enhancement, but rather mild-to-moderate diffuse high signal in deep white matter, which later disappeared. These findings suggest that multiple low-signal foci on T2-weighted images with contrast enhancement may be characteristic of DNL, and that contrast-enhanced imaging is useful to differentiate this condition from mild leukoencephalopathy.

Adolescent↗

PubMed2003

Search for nu(e) from the sun at Super-Kamiokande-I.

We present the results of a search for low energy nu(e) from the Sun using 1496 days of data from Super-Kamiokande-I. We observe no significant excess of events and set an upper limit for the conversion probability to nu(e) of the 8B solar neutrino. This conversion limit is 0.8% (90% C.L.) of the standard solar model's neutrino flux for total energy=8-20 MeV. We also set a flux limit for monochromatic nu(e) for E(nu(e))=10-17 MeV.

Journal Article↗

PubMed2003

Meningioma showing VHL gene inactivation in a patient with von Hippel-Lindau disease.

The genetic mechanism of the tumorigenesis of meningioma in conjunction with von Hippel-Lindau (VHL) disease is unclear. The authors present a case of VHL disease associated with a posterior fossa meningioma and with multiple cerebellar hemangioblastomas. A germline mutation of the VHL gene and loss of heterozygosity on the VHL gene locus in 3p were detected in the meningioma. Tumorigenesis of a meningioma associated with VHL disease could be caused by inactivation of both alleles of the VHL gene.

Aged↗

PubMed2003

Search for supernova relic neutrinos at Super-Kamiokande.

A search for the relic neutrinos from all past core-collapse supernovae was conducted using 1496 days of data from the Super-Kamiokande detector. This analysis looked for electron-type antineutrinos that had produced a positron with an energy greater than 18 MeV. In the absence of a signal, 90% C.L. upper limits on the total flux were set for several theoretical models; these limits ranged from 20 to 130 macro nu(e) cm(-2) s(-1). Additionally, an upper bound of 1.2 macro nu(e) cm(-2) s(-1) was set for the supernova relic neutrino flux in the energy region E(nu)>19.3 MeV.

Journal Article↗

PubMed2003

Release of recombinant human bone morphogenetic protein 2 from a newly developed carrier.

After implantation of a polymer-coated gelatin sponge (PGS) containing either 0.4 or 1.0 mg of 125I-rhBMP-2 for each 1 cm(3) of PGS into the right ulnar of rabbits, changes in the level of radioactivity at the implant site and in the blood were measured for 21 days after implantation, and the cumulative excretion ratio of radioactivity in the urine and feces was calculated. For both doses, radioactivity at the implant site was eliminated biphasically. The concentration of trichloroacetic acid (TCA)-precipitable radioactivity in the blood reached a maximum 6 h after implantation, at which time it was equivalent to 1.41% of the administered dose (0.4 mg/cm(3)). The remaining radioactivity was eliminated rapidly thereafter, falling below the detection limit within 48 h. The t(1/2alpha) was about 0.1 days, the t(1/2beta) was about 3 days, and the mean resident time (MRT) value was about 4 days. By 17 days after implantation, 88.1% of the administered radioactivity had been excreted in the urine, and 1.7% had been excreted in the feces. TCA precipitation test results indicated that most of the radioactivity excreted in urine was a low-molecular weight decomposition product. At 21 days after implantation, the radioactivity of the PGS implant site had declined to 0.5% of the administered amount. Autoradiographs of the implant site taken 28 days after implantation revealed that, at both doses, the residual radioactivity was confined to the area of the implanted PGS. These results indicate that PGS retains an appropriate amount of recombinant human bone morphogenetic protein 2 (rhBMP-2) at the orthotopically implanted site for at least 21 days enough to induce bone regeneration. Thus, PGS shows great clinical potential as a carrier for rhBMP-2.

Animals↗

PubMed2003

Indications of neutrino oscillation in a 250 km long-baseline experiment.

The K2K experiment observes indications of neutrino oscillation: a reduction of nu(mu) flux together with a distortion of the energy spectrum. Fifty-six beam neutrino events are observed in Super-Kamiokande (SK), 250 km from the neutrino production point, with an expectation of 80.1(+6.2)(-5.4). Twenty-nine one ring mu-like events are used to reconstruct the neutrino energy spectrum, which is better matched to the expected spectrum with neutrino oscillation than without. The probability that the observed flux at SK is explained by statistical fluctuation without neutrino oscillation is less than 1%.

Journal Article↗

PubMed2003

Effects of air current speed on gas exchange in plant leaves and plant canopies.

To obtain basic data on adequate air circulation to enhance plant growth in a closed plant culture system in a controlled ecological life support system (CELSS), an investigation was made of the effects of the air current speed ranging from 0.01 to 1.0 m s-1 on photosynthesis and transpiration in sweetpotato leaves and photosynthesis in tomato seedlings canopies. The gas exchange rates in leaves and canopies were determined by using a chamber method with an infrared gas analyzer. The net photosynthetic rate and the transpiration rate increased significantly as the air current speeds increased from 0.01 to 0.2 m s-1. The transpiration rate increased gradually at air current speeds ranging from 0.2 to 1.0 m s-1 while the net photosynthetic rate was almost constant at air current speeds ranging from 0.5 to 1.0 m s-1. The increase in the net photosynthetic and transpiration rates were strongly dependent on decreased boundary-layer resistances against gas diffusion. The net photosynthetic rate of the plant canopy was doubled by an increased air current speed from 0.1 to 1.0 m s-1 above the plant canopy. The results demonstrate the importance of air movement around plants for enhancing the gas exchange in the leaf, especially in plant canopies in the CELSS.

Air Conditioning↗

PubMed2003

Antimuscarinics and the overactive detrusor--which is the main mechanism of action?

Contraction of the bladder, voluntary or involuntary, involves stimulation of the muscarinic receptors on the detrusor by acetylcholine, released from activated cholinergic nerves. Antimuscarinics are the drugs of choice for treatment of detrusor overactivity and the overactive bladder (OAB) syndrome. However, antimuscarinics at clinically recommended doses have little effect on voiding contractions, and may act mainly during the bladder storage phase, during which there is normally no parasympathetic outflow from the spinal cord. Supporting this, antimuscarinics have been shown to reduce bladder tone during storage, and to increase cystometric bladder capacity. A basal release of acetylcholine from non-neuronal (urothelial) as well as neuronal sources has been demonstrated in isolated human detrusor muscle. It is suggested that this release, which is increased by stretching the muscle and in the aging bladder, contributes to detrusor overactivity and OAB by eventually increasing bladder afferent activity during storage.

Humans↗

PubMed2003

Accumulation of 1,2-propanediol and enhancement of aerobic stability in whole crop maize silage inoculated with Lactobacillus buchneri.

AIMS: To assess the effects of inoculation of Lactobacillus buchneri on the ensiling properties and aerobic stability of maize silage. METHODS AND RESULTS: Chopped whole crop maize was ensiled in 0.5 litre airtight polyethylene bottles (0.4 kg per bottle) and in double-layered, thin polyethylene bags (15 kg per bag), with or without inoculation of Lact. buchneri. The silos were stored for two to four months and the chemical composition, microbial numbers and aerobic stability were determined. Inoculation lowered lactic acid and yeasts, and increased acetic acid and pH value, resulting in improved aerobic stability of the silages. Inoculated silages produced 1,2-propanediol, the content of which increased as ensiling was prolonged, and nearly 50 g kg-1 dry matter had accumulated after four months of storage. The effects of inoculation, however, were much less pronounced in silages prepared in bags. Mannitol was found in all silages; the production was lowered by Lact. buchneri treatment and appeared to be unrelated to the accumulation of 1,2-propanediol. CONCLUSIONS: Inoculation of Lact. buchneri occasionally causes accumulation of 1,2-propanediol in silages without further degradation into propionic acid and 1-propanol. SIGNIFICANCE AND IMPACT OF THE STUDY: Substantial amounts of 1,2-propanediol could be consumed by ruminants when fed on silages inoculated with Lact. buchneri. In addition to increasing acetic acid, attention needs to be paid to 1,2-propanediol because the two fermentation products might affect the intake and utilization of silage-based diets.

Aerobiosis↗

PubMed2003

Effect of nitrous oxide on dental patients with cerebral palsy -- using an electromyogram (EMG) from orofacial muscles as an index.

The efficacy of nitrous oxide (N2O) inhalation on the elevated orofacial muscle tonus during dental treatment in patients with cerebral palsy (CP) was studied by measuring the mean frequency of electromyographic (EMG) discharge, blood pressure (BP) and heart rate (HR) taking mentally retarded patients (MR) as a control. At a pre-treatment stage, the mean frequency of the EMG was higher in the CP patients than in the MR patients. By forcing the jaw open, the mean frequency of the EMG, BP and HR was elevated significantly in both types of patients. The enhanced level of the mean frequency of the EMG was higher in the CP patients than in the MR patients. After inhalation of N2O, the mean frequency was reduced significantly in both types of patients, however, the reduction rate was higher in the CP patients than the MR patients; BP and HR were not affected. These results demonstrate the selective efficacy of N2O in reducing the orofacial muscle tonus in CP patients during dental treatment probably because of the N2O inhibiting the function of the central nervous system. The present study therefore suggests the beneficial properties of N2O induced sedation performed during dental treatment on CP patients.

Adult↗

PubMed2003

Alpha-synuclein-positive structures in association with diffuse neurofibrillary tangles with calcification.

alpha-Synuclein is known to be a major constituent of the Lewy bodies (LBs) in Parkinson's disease (PD) and the neuronal and glial cytoplasmic inclusions (NCIs, GCIs) in multiple system atrophy. alpha-Synuclein-positive inclusions such as LBs, NCIs and GCIs sometimes show colocalization with tau-positive neurofilaments. Studies using alpha-synuclein immunohistochemistry have often found LBs in the amygdala of patients with familial or sporadic Alzheimer's disease (AD), as well as in patients with Down's syndrome and AD. However, no studies have reported alpha-synuclein-positive structures in cases of diffuse neurofibrillary tangles with calcification (DNTC), which is characterized by numerous neurofibrillary tangles (NFTs) throughout the cerebral cortex but few, if any, senile plaques. We investigated the distribution of alpha-synuclein-positive structures in two cases of DNTC: a 65-year-old woman (brain weight, 850 g) and a 75-year-old woman (brain weight, 800 g). In both cases, severe cerebral atrophy predominant in the temporal lobe was noted. Microscopically, alpha-synuclein-positive intracytoplasmic inclusions and neurites were found in the superior temporal lobe (within the temporal pole), amygdala, parahippocampus, entorhinal cortex and insula, the regions most affected by the NFTs. alpha-Synuclein-positive intracytoplasmic inclusions were rare or absent in other regions of the cerebral cortex and brainstem. This distribution pattern differs from that of PD or dementia with LBs. Our findings suggest that the accumulation pattern of alpha-synuclein is a pathological feature of DNTC, and that DNTC is associated with accumulation of both tau and alpha-synuclein.

Aged↗

PubMed2003

Frameless stereotactic radiosurgery with mobile CT, mask immobilization and micro-multileaf collimators.

We present frameless stereotactic radiosurgery using mobile CT, thermal plastic mask fixation, a vacuum-form body immobilizer and micro-multileaf collimators. A linear accelerator and a self-moving helical CT scanner gantry were installed in the same room. The isocenter of irradiation can be also aligned with the center of the CT gantry by rotating the couch. A thermal plastic mask and vacuum-form body immobilizer was used for registration and immobilization. The advantages of this system are as follows: 1) Accurate and painless frameless fractionated irradiation can be performed smoothly, as the patient's head is fixed without exchanging the couch from CT scanning to irradiation system. 2) This mask system can be applied to children, infants or adults with a previous craniotomy bone flap that must have a fixation pin placed into it. This system can be also used for fractionated radiotherapy without painful skull pin-fixed frame. 3) 1 mm micro-multileaf collimators enable irregular contour irradiation. 4) Image fusion (among CT, MRI, angiography, and PET) and 3D images can be used for irradiation planning. 5) This system can be used on any part of the body. 6) This system can be installed in any irradiation room without any extension or new construction.

Brain Neoplasms↗