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M Shiozawa

Publications and source records attributed to M Shiozawa.

At least 19 recordsLinked to original sources
PubMed2006

Measurement of atmospheric neutrino flux consistent with tau neutrino appearance.

A search for the appearance of tau neutrinos from nu(mu) <--> nu(tau) oscillations in the atmospheric neutrinos has been performed using 1489.2 days of atmospheric neutrino data from the Super-Kamiokande-I experiment. A best fit tau neutrino appearance signal of 138+/-48(stat)-32(+15)(syst) events is obtained with an expectation of 78+/-26(syst). The hypothesis of no tau neutrino appearance is disfavored by 2.4 sigma.

Journal Article↗
PubMed2006

Retroperitoneal hand-assisted laparoscopic surgery for endoscopic adrenalectomy.

Although hand-assisted laparoscopic surgery (HALS) is very common in various laparoscopic procedures, it is rarely used for retroperitoneal endoscopic adrenalectomy because of the small working area. The authors evaluate HALS in endoscopic adrenalectomy with respect to its use as a rescue procedure in complicated cases. In their department, 47 patients underwent endoscopic adrenalectomies between 1998 and 2004. Mainly because of complicated anatomy, three primary aldosteronism cases were converted to retroperitoneal HALS. This involved making an additional 6 cm skin incision, into which the surgeon's left hand was inserted, with the palm used to create a sufficient visual field and working area. The fingers were used for tactile sensation and blunt resection. For these three cases, successful retroperitoneal HALS in endoscopic adrenalectomy resulted in no mortality or morbidity. These findings indicate that this procedure is a feasible technique for complicated benign adrenal tumor cases.

Adrenalectomy↗
PubMed2004

Evidence for an oscillatory signature in atmospheric neutrino oscillations.

Muon neutrino disappearance probability as a function of neutrino flight length L over neutrino energy E was studied. A dip in the L/E distribution was observed in the data, as predicted from the sinusoidal flavor transition probability of neutrino oscillation. The observed L/E distribution constrained nu(micro)<-->nu(tau) neutrino oscillation parameters; 1.9x10(-3) 0.90 at 90% confidence level.

Journal Article↗
PubMed2004

Search for electron neutrino appearance in a 250 km long-baseline experiment.

We present a search for electron neutrino appearance from accelerator-produced muon neutrinos in the K2K long-baseline neutrino experiment. One candidate event is found in the data corresponding to an exposure of 4.8 x 10(19) protons on target. The expected background in the absence of neutrino oscillations is estimated to be 2.4+/-0.6 events and is dominated by misidentification of events from neutral current pi(0) production. We exclude the nu(micro) to nu(e) oscillations at 90% C.L. for the effective mixing angle in the 2-flavor approximation of sin((2)2theta(microe)( approximately 1/2sin((2)2theta(13))>0.15 at Deltam(2)(microe)=2.8 x 10(-3) eV(2), the best-fit value of the nu(micro) disappearance analysis in K2K. The most stringent limit of sin((2)2theta(microe)<0.09 is obtained at Deltam(2)(microe)=6 x 10(-3) eV(2).

Journal Article↗
PubMed2004

Limits on the neutrino magnetic moment using 1496 days of Super-Kamiokande-I solar neutrino data.

A search for a nonzero neutrino magnetic moment has been conducted using 1496 live days of solar neutrino data from Super-Kamiokande-I. Specifically, we searched for distortions to the energy spectrum of recoil electrons arising from magnetic scattering due to a nonzero neutrino magnetic moment. In the absence of a clear signal, we found micro(nu)</=(3.6x10(-10))micro(B) at 90% C.L. by fitting to the Super-Kamiokande day-night spectra. The fitting took into account the effect of neutrino oscillation on the shapes of energy spectra. With additional information from other solar neutrino and KamLAND experiments constraining the oscillation region, a limit of micro(nu)</=(1.1x10(-10))micro(B) at 90% C.L. was obtained.

Journal Article↗
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

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

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↗
PubMed2002

Motor neuron disease with dementia combined with degeneration of striatonigral and pallidoluysian systems.

This study concerns an autopsy case of motor neuron disease with dementia (MND-D) that exhibited unusual clinical and neuropathological findings. The patient was a Japanese man without any relevant family history who was 60 years old at the time of death. His clinical manifestation included character change at the age of 54, followed by frozen gait, dysarthria and bradykinesia and he was diagnosed with Parkinson's disease. He gradually developed spastic paresis and died of respiratory failure 6 years after onset of the illness. Neuropathological examinations showed prominent degeneration in the striatonigral and pallidoluysian systems in addition to the neuronal loss and microvacuolation in the second to third layers of the frontal and temporal cortex, the involvement of the upper and lower motor neuron systems and the presence of ubiquitinated neuronal inclusions. To our knowledge, five cases of motor neuron disease (MND) combined with pallido-nigro-luysian atrophy (PNLA) have been reported previously, but the present case is the first report of MND-D combined with the degeneration of the striatonigral and pallidoluysian systems. Such an association may represent more than a coincidental occurrence, and it suggests that MND-D is not simply a disease of the motor neuron system but a multisystem degeneration.

Dementia↗
PubMed2001

Solar 8B and hep neutrino measurements from 1258 days of Super-Kamiokande data.

Solar neutrino measurements from 1258 days of data from the Super-Kamiokande detector are presented. The measurements are based on recoil electrons in the energy range 5.0-20.0 MeV. The measured solar neutrino flux is 2.32+/-0.03(stat)+0.08-0.07(syst)x10(6) cm(-2) x s(-1), which is 45.1+/-0.5(stat)+1.6-1.4(syst)% of that predicted by the BP2000 SSM. The day vs night flux asymmetry (Phi(n)-Phi(d))/Phi(average) is 0.033+/-0.022(stat)+0.013-0.012(syst). The recoil electron energy spectrum is consistent with no spectral distortion. For the hep neutrino flux, we set a 90% C.L. upper limit of 40x10(3) cm(-2) x s(-1), which is 4.3 times the BP2000 SSM prediction.

Journal Article↗
PubMed2001

Constraints on neutrino oscillations using 1258 days of Super-Kamiokande solar neutrino data.

We report the result of a search for neutrino oscillations using precise measurements of the recoil electron energy spectrum and zenith angle variations of the solar neutrino flux from 1258 days of neutrino-electron scattering data in Super-Kamiokande. The absence of significant zenith angle variation and spectrum distortion places strong constraints on neutrino mixing and mass difference in a flux-independent way. Using the Super-Kamiokande flux measurement in addition, two allowed regions at large mixing are found.

Journal Article↗
PubMed2001

Automated construction of high-density comparative maps between rat, human, and mouse.

Animal models have been used primarily as surrogates for humans, having similar disease-based phenotypes. Genomic organization also tends to be conserved between species, leading to the generation of comparative genome maps. The emergence of radiation hybrid (RH) maps, coupled with the large numbers of available Expressed Sequence Tags (ESTs), has revolutionized the way comparative maps can be built. We used publicly available rat, mouse, and human data to identify genes and ESTs with interspecies sequence identity (homology), identified their UniGene relationships, and incorporated their RH map positions to build integrated comparative maps with >2100 homologous UniGenes mapped in more than one species (approximately 6% of all mammalian genes). The generation of these maps is iterative and labor intensive; therefore, we developed a series of computer tools (not described here) based on our algorithm that identifies anchors between species and produces printable and on-line clickable comparative maps that link to a wide variety of useful tools and databases. The maps were constructed using sequence-based comparisons, thus creating "hooks" for further sequence-based annotation of human, mouse, and rat sequences. Currently, this map enables investigators to link the physiology of the rat with the genetics of the mouse and the clinical significance of the human.

Algorithms↗
PubMed2000

Tau neutrinos favored over sterile neutrinos in atmospheric muon neutrino oscillations.

The previously published atmospheric neutrino data did not distinguish whether muon neutrinos were oscillating into tau neutrinos or sterile neutrinos, as both hypotheses fit the data. Using data recorded in 1100 live days of the Super-Kamiokande detector, we use three complementary data samples to study the difference in zenith angle distribution due to neutral currents and matter effects. We find no evidence favoring sterile neutrinos, and reject the hypothesis at the 99% confidence level. On the other hand, we find that oscillation between muon and tau neutrinos suffices to explain all the results in hand.

Journal Article↗
PubMed2000

Gene structure and chromosomal mapping of the rat smooth muscle calponin gene.

Smooth muscle cells (SMC) express a battery of lineage-restricted genes whose encoded proteins impart the unique contractile phenotype that characterizes this muscle type. While the encoded function of many SMC-restricted genes has been extensively analyzed, less is known about their position within the genome and the regulatory factors governing their transcription. In this report, we define the gene structure, 5' promoter analysis, and chromosomal mapping of the rat smooth muscle calponin (CnnI) gene. The rat CnnI gene is comprised of seven exons spanning approximately 8 kb of genomic sequence. The intron-exon boundaries of the rat CnnI gene match precisely those in human and mouse. Primer extension and RNase protection assays indicate two major transcription start positions (tsp). Comparative sequence analysis of the 5' promoter region reveals several conserved cis regulatory elements, including a TA-rich element within 30 nt of the tsp that could be a recognition site for TATA-binding protein and two CCAAT boxes. Transient and stable transfection studies support the hypothesis that distal regulatory elements confer SMC-restricted expression of CnnI. Finally, using an F2 intercross, we have mapped the rat CnnI gene to the telomeric end of Chromosome (Chr) 8. These studies provide additional information relating to the control of CnnI gene expression and provide a platform to begin assessing the potential linkage of CnnI to spontaneous and experimental disease phenotypes in rats.

Animals↗
PubMed2000

Neuronal loss and neurofibrillary degeneration in the hippocampal cortex in late-onset sporadic Alzheimer's disease.

To explore more fully the relationship between neuronal death and neurofibrillary degeneration, unaffected neurons, intracellular neurofibrillary tangles (i-NFT) and extracellular NFT (e-NFT) in 22 patients with late-onset sporadic Alzheimer's disease (AD) were morphometrically evaluated in eight subdivisions of the hippocampal cortex, using the Gallyas hematoxylin-eosin stain. The subdivisions examined included CA4, CA3, CA2, CA1 (CA: cornu ammonis), prosubiculum (PRO), subiculum and presubiculum (PRE), parasubiculum (PARA) and the entorhinal cortex (ENT). The unaffected neuron density was significantly lower and both i-NFT and e-NFT densities were significantly higher in subdivisions other than CA4 and CA3 in AD patients compared with those in the aged controls. Unaffected neuron density was significantly, inversely correlated with e-NFT density and with total NFT density in all subdivisions except for PRE in AD patients. Especially in CA2, CA1, PRO and ENT, there were strong correlations between the neuron density and these NFT densities. Both unaffected neuron and e-NFT densities in CA1 and ENT were significantly correlated with the disease duration. The i/e-NFT ratio, an index of the degree and/or rate of progress of neuronal death via neurofibrillary degeneration, showed the lowest value in ENT in AD patients. The findings suggest that neuronal death via neurofibrillary degeneration starts earliest and/or most rapidly progresses in ENT. Furthermore, the i/e-NFT ratios in both ENT and CA1 were significantly correlated with the disease duration, suggesting that the neuronal death pattern in the two subdivisions parallels disease progression.

Age Factors↗
PubMed1999

PLP-I: a novel prolactin-like gene in rodents.

In this report, we describe molecular cloning and characterization of cDNAs encoding a novel rat prolactin-like protein. The rat cDNAs were isolated from the decidua and the gene was named PLP-I. cDNAs for the mouse equivalent were also cloned by the cross-hybridization technique. Pregnancy-specific expression of the rat PLP-I gene was observed in the rat placenta by Northern analysis. Location of signal peptide cleavage sites in rat and mouse pre-PLP-I proteins was predicted using a theoretical method. A molecular phylogenetic tree for the growth hormone-prolactin superfamily including the novel member, PLP-I, constructed using the neighbor-joining method, places rat/mouse PLP-I closest to rat/mouse placental lactogen I and II.

Amino Acid Sequence↗