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Biomedical subjects

T Momose

Publications and source records attributed to T Momose.

At least 37 records · Page 2Linked to original sources
PubMed2000

Observation of rovibrational dephasing of molecules in parahydrogen crystals by frequency domain spectroscopy

Rotation-vibration transitions of methane molecules embedded in parahydrogen crystals were investigated through Fourier transform infrared spectroscopy. Each transition shows extremely sharp peaks with a Lorentzian line shape profile, which indicates the spectra are free from inhomogeneous broadening. The steep temperature dependence of the linewidths observed in the range between 3.7 and 8. 5 K is interpreted to be a result of the pure dephasing relaxation mechanism. A remarkable difference in population relaxation widths between stretching and bending vibrational excited states was also found.

Journal Article↗
PubMed2000

Tbx5 and the retinotectum projection.

Dorsal and ventral aspects of the eye are distinct from the early stages of development. The developing eye cup grows dorsally, and the choroidal fissure is formed on its ventral side. Retinal axons from the dorsal and ventral retina project to the ventral and dorsal tectum, respectively. Misexpression of the Tbx5 gene induced dorsalization of the ventral side of the eye and altered projections of retinal ganglion cell axons. Thus, Tbx5 is involved in eye morphogenesis and is a topographic determinant of the visual projections between retina and tectum.

Animals↗
PubMed2000

The effect of knot location, suture material, and suture size on the gliding resistance of flexor tendons.

The effect of knot location, suture material, and suture size on gliding resistance between the pulley and flexor tendon was investigated in a canine model. Different suture materials [monofilament nylon (Ethilon), braided polyester suture coated with silicone (Ticron) and uncoated braided polyester suture (Mersilene)] and suture sizes (4-0, 5-0) were tested. A knot was made on either the volar surface, on one lateral side, or on both lateral sides of canine hind-paw tendons, and gliding resistance was measured. In addition, the frictional coefficient between three suture materials (4-0 nylon, 4-0 Ticron, 4-0 Mersilene) and a nylon rod were measured. The gliding resistance of the tendon with knots on both sides was highest, while tendons with one lateral knot had the lowest resistance (p < 0.01). The gliding resistance of 4-0 suture size was higher than that of 5-0 size (p < 0.0001). The coefficient of friction of nylon was lower than that of braided polyester suture (Ticron or Mersilene) (p < 0.001). The placement of knots and choice of suture material affect gliding resistance after tendon repair, and may, therefore, have an effect on the result of tendon repair.

Animals↗
PubMed2000

Multiple functions of fibroblast growth factor-8 (FGF-8) in chick eye development.

Fibroblast growth factor-8 (FGF-8) is an important signaling molecule in the generation and patterning of the midbrain, tooth, and limb. In this study we show that it is also involved in eye development. In the chick, Fgf-8 transcripts first appear in the distal optic vesicle when it contacts the head ectoderm. Subsequently Fgf-8 expression increases and becomes localized to the central area of the presumptive neural retina (NR) only. Application of FGF-8 has two main effects on the eye. First, it converts presumptive retinal pigment epithelium (RPE) into NR. This is apparent by the failure to express Bmp-7 and Mitf (a marker gene for the RPE) in the outer layer of the optic cup, coupled with the induction of NR genes, such as Rx, Sgx-1 and Fgf-8 itself. The induced retina displays the typical multilayered cytoarchitecture and expresses late neuronal differentiation markers such as synaptotagmin and islet-1. The second effect of FGF-8 exposure is the induction of both lens formation and lens fiber differentiation. This is apparent by the expression of a lens specific marker, L-Maf, and by morphological changes of lens cells. These results suggest that FGF-8 plays a role in the initiation and differentiation of neural retina and lens.

Animals↗
PubMed2000

Different cortical activity in reading of Kanji words, Kana words and Kana nonwords.

We report a positron emission tomography study on reading of Japanese Kanji (morphograms) words, Kana (phonograms) words and Kana nonwords using statistical parametric mapping. Activity was more pronounced in the lateral fusiform gyrus (Area 37) in Kanji, in contrast to the greater activation in the middle and inferior occipital gyri (Areas 18 and 19) and the deep perisylvian temporo-parietal area (Areas 40/22 and 22/21) in Kana, suggesting that Kanji and Kana are processed differently.

Adolescent↗
PubMed2000

Spontaneous B-cell IgE production in a patient with remarkable eosinophilia and hyper IgE.

BACKGROUND: The pathophysiology of eosinophilia and hyper-IgE is not fully elucidated yet. OBJECTIVE: To clarify the pathophysiology of a patient with remarkable eosinophilia and hyper IgE, we examined cytokine levels in serum, surface antigens of peripheral blood eosinophils and IgE production in vitro. RESULTS: Concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin-3 (IL-3), interleukin-4 (IL-4), interleukin-5 (IL-5), and granulocyte/macrophage-colony stimulating factor (GM-CSF) in the serum were 21 pg/mL, <15 pg/mL, <15 pg/mL, 8 pg/mL, and <5 pg/mL pg/mL, respectively. Newly expressed surface antigens CD4, CD25, CD69, and HLA-DR, but not CD54, were observed on peripheral blood eosinophils. Extremely high levels of IgE secretion was found in the patient's mononuclear cells without stimuli; this was not enhanced by IL-4 or IL-4 plus anti-CD40 monoclonal antibody stimulation. Furthermore, highly purified B cells spontaneously produced large amounts of IgE and the production was not enhanced in addition of his T cells. CONCLUSION: The eosinophils were activated, and the B cells spontaneously produced IgE independently of T cells or cytokines, suggesting that intrinsic abnormality of B cells leading to dysregulated production of IgE in this disease.

Aged↗
PubMed2000

Applications of microelectroporation for studies of chick embryogenesis.

A technique by which genes can be introduced into the cells and tissues of developing embryos has great potential for studying the roles of genes during vertebrate embryogenesis. The 'microelectroporation' technique, in which DNA is introduced into cells within a restricted area of developing chick embryos with high reproducibility, was developed by the authors. In this review, the advantages and applications of this microelectroporation technique for developmental studies and functional analysis of genes in chick embryos is discussed.

Animals↗
PubMed2000

Fluorinative Beckmann fragmentation: fluorinative alpha-cleavage of cyclic ketoximes by diethylaminosulfur trifluoride.

Diethylaminosulfur trifluoride reacted with cyclic ketoximes bearing substituent(s) that can stabilize a carbocation to cause fluorinative fragmentation, affording fluorinated carbonitrile. Ketoximes lacking such substituents afforded complex mixtures. However, the introduction of a sulfur functionality, which can stabilize a carbocation and can be easily removed from the reaction products, into the ketoxime was effective for producing the fluorinative fragmentation.

Diethylamines↗
PubMed2000

Alpha-bromo-alpha,alpha-difluoroallyl derivatives as synthetic intermediate: nucleophilic substitution of alpha-bromo-alpha,alpha-difluoroallyl derivatives in the presence of palladium catalysts.

The palladium catalyzed nucleophilic substitution of alpha-bromo-alpha,alpha-difluoroallyl derivatives turned out to be an efficient method for the preparation of several fluorinated organic molecules. Several soft carbon nucleophiles regioselectively reacted with 3-bromo-3,3-difluoropropene (BDFP) to give the 3-substituted 1,1-difluoroalkenes. Phenylzinc chloride and tributylphenyltin afforded 1-fluoro-1,3-diphenylpropene. The radical bromination of 3-substituted 1,1-difluoroalkenes provided 1-substituted BDFPs, and a 1-substituted BDFP reacted with carbon nucleophiles to give 1,3-disubstituted 3,3-difluoroalkenes. For the reaction of nitrogen nucleophiles with BDFP, an amine and the sodium salts of the carbamates reacted with BDFP at the gamma-position. However, the sodium salts of the sulfoneamide predominantly attacked at the alpha-position.

Catalysis↗
PubMed2000

Pulmonary hypertension as a result of asymptomatic portosystemic shunt.

This report describes a patient with severe pulmonary hypertension accompanied by a congenital intrahepatic portosystemic shunt. Primary pulmonary hypertension was suspected initially because none of the classic symptoms of a portosystemic shunt were present. Physicians should note that disorders of the portal system may cause pulmonary hypertension even in the absence of symptoms suggesting liver disease.

Female↗
PubMed1999

Relief of hemiballism from a basal ganglia arteriovenous malformation after radiosurgery.

A patient with a 3-year history of progressive hemiballism presented with an unruptured arteriovenous malformation (AVM) in the contralateral caudate nucleus and putamen. PET demonstrated a matched reduction of cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) in the basal ganglia and adjacent frontal lobe. The patient underwent radiosurgery for the AVM. After a period of no clinical change for 6 months, the movement disorder resolved by month 7 post-treatment. The AVM was successfully obliterated 2 years after irradiation without any significant change in the regional CBF or CMRO2.

Arteriovenous Malformations↗
PubMed1999

Efficient targeting of gene expression in chick embryos by microelectroporation.

During vertebrate embryonic development, a key to unraveling specific functions of gene products is the capability to manipulate expression of the gene of interest at the desired time and place. For this, we developed a 'microelectroporation' technique by which DNA can be locally introduced into a targeted site of avian embryos, restricting spatial expression of the protein products during development. This technique involved injection of DNA solution in ovo around the target tissue and pinpoint application of an electric field by tungsten electrodes, allowing efficient and reproducible targeted gene transfer, for example, into an optic vesicle, somites, cranial mesoderm and limb mesenchyme. Because of the locality of gene introduction and its expression, survival rates of the embryos were high: approximately 90% of the embryos injected in optic vesicles were alive for at least 1 day after microelectroporation. The instantaneous gene transfer into embryonic cells allowed rapid expression of protein products such as green fluorescence protein within 2.5 h with fluorescence maintained for 3 days of incubation. This improved technique provides a convenient and efficient way to express transgenes in a spatially and temporally restricted manner in chicken embryos.

Animals↗
PubMed1999

Contact area of the trapeziometacarpal joint.

Eighteen cadaver hands were studied to determine the contact area of the trapeziometacarpal joint by using silicone rubber casts. Casting material was introduced into the trapeziometacarpal joint during several motions of the thumb and the contact location was observed. The ratios of the contact area to the total joint area were calculated. The contact locations in opposition were the radial, volar, and ulnar segments of the trapezium and the dorsal, radial, and volar segments of the metacarpal. On average, 53% of the trapezium was in contact with 53% of the metacarpal in opposition, while 28% of the trapezium was in contact with 28% of the metacarpal in palmar abduction and 25% of the trapezium was in contact with 25% of the metacarpal in radial abduction. The contact area was the largest in opposition. The trapeziometacarpal joint is stable in opposition and facilitates a strong pinch.

Aged↗
PubMed1999

Interferon-gamma increases CD62L expression on human eosinophils.

BACKGROUND: L-selectin (CD62L) and Mac-1 (CD11b/CD18) play a crucial role in the infiltration of eosinophils. However, changes in CD62L and CD11b expression on eosinophils after stimulation with cytokines were little studied. METHODS: Eosinophils in peripheral blood of healthy volunteers were purified and cultured with interleukin-5 (IL-5), granulocyte/macrophage colony-stimulating factor (GM-CSF) or interferon-gamma (IFN-gamma). After up to 24 h incubation, CD62L and CD11b expression were examined using flow cytometry. The effects of dexamethasone (Dex), cycloheximide (CHX) or theophylline on CD62L expression on IFN-gamma-stimulated eosinophils were also studied. RESULTS: IL-5 or GM-CSF downregulated CD62L and upregulated CD11b expression on eosinophils after 30 min stimulation. Conversely, IFN-gamma upregulated CD62L after 12 h stimulation in a time- and dose-dependent manner, and had no effect on CD11b expression. Dex, CHX or theophylline dose-dependently decreased CD62L expression on IFN-gamma-stimulated eosinophils. CONCLUSIONS: IFN-gamma is a particular cytokine which can increase CD62L expression on circulating or infiltrated human eosinophils. It is suggested that protein synthesis and intracellular cAMP participate in the increase in L-selectin expression on IFN-gamma-stimulated eosinophils.

Antineoplastic Agents↗
PubMed1999

[Phase 2 clinical study of 123I-IBF, a dopamine D2 receptor imaging agent, to evaluate clinical efficacy and safety in Parkinson's disease and Parkinson syndromes].

A Phase 2 multicenter trial of 123I-IBF, (S)-5-iodo-7-N-[(1-ethyl-2- pyrrolidinyl)methyl]carboxamido-2,3-dihydrobenzofuran, was conducted to evaluate its clinical efficacy and safety in 158 patients with Parkinson's disease (PD) or Parkinson syndromes (PS). SPECT data were acquired at two hours (2H-SPECT), after intravenous injection of 123I-IBF (167 MBq). Additional SPECT scan at three hours (3H-SPECT) and dynamic SPECT scan at most until one hour were performed when possible. No severe side effects due to 123I-IBF injection were observed. The sensitivity, specificity and accuracy for discriminating PS from PD using the striatal specific binding count-to-frontal cortex count ratio (St/Fc-1) in 3H-SPECT were 72.7%, 81.0% and 78.1% in 64 clinically definite cases (i.e., typical cases), respectively. The putamen-to-caudate ratios were significantly lower in striatonigral degeneration compared with those in PD. The contralateral-to-ipsilateral ratios against the symptomatic side of tremor and/or rigidity in the patients with PD (Hoehn & Yahr I) were significantly higher than the left-to-right ratios in the normal controls. St/Fc-1 in 3H-SPECT was significantly lower in the patients showing a poor response to levodopa than in those showing a good response. The dopamine D2 receptor binding potential (k3/k4), obtained by dynamic SPECT based on compartment model analysis, correlated well with the striatal specific binding count-to-occipital cortex count ratio. These results suggest that 123I-IBF is a promising agent for differential diagnosis and pathophysiological evaluation of PD and PS.

Adult↗
PubMed1998

Method for the separation of the unconjugates and conjugates of chenodeoxycholic acid and deoxycholic acid by two-dimensional reversed-phase thin layer chromatography with methyl beta-cyclodextrin.

A simple and efficient method for the separation of individual unconjugated bile acids and their glycine- and taurine-amidated, 3-sulfated, 3-glucosylated and 3-glucuronidated conjugates is described. The method involves the use of a two-dimensional (2D) reversed-phase (RP) high-performance thin-layer chromatographic (HPTLC) technique with methyl beta-cyclodextrin (Me-beta-CD). Five major unconjugated bile acids, chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), ursodeoxycholic acid and lithocholic acid, and their conjugates were examined as the solutes. A high degree of separation of individual bile acids in each homologous series was achieved on a RP-HPTLC plate by developing with aqueous methanol in the first dimension and the same solvent system containing Me-beta-CD in the second dimension. In particular, all of the six 'difficult-to-separate' pairs, unconjugated CDCA and DCA and their conjugated forms with glycine, taurine, sulfuric acid, D-glucose and D-glucuronic acid, were effectively resolved by adding Me-beta-CD in the aqueous mobile phases with the formers having larger mobilities than the latter. The application of this 2D inclusion RP-HPLC method to the separation of glycine-conjugated bile acids in human bile is also described. The present method would be useful for separating and characterizing these bile acids present in biological materials.

Bile↗
PubMed1998

Mechanism of short-term memory and repetition in conduction aphasia and related cognitive disorders: a neuropsychological, audiological and neuroimaging study.

To evaluate the role of the sub-cortical white matter and cortical areas of the supramarginal gyrus in short-term memory impairment (shortened digit or letter span) and repetition difficulty, four patients with conduction aphasia and impaired short-term memory and two patients with only short-term memory impairment were given digit span, letter span, speech audiometry and dichotic listening tests. The results showed that in most of the patients letter span was inferior to digit span and that bilateral ear suppression in the dichotic listening test was observed in two patients with a lesion in the inferior part of the supramarginal gyrus, suggesting that what was affected was phonological information and that the supramarginal gyrus was the storage site. The overlapped lesion of conduction aphasia patients with short-term memory impairment was the periventricular white matter at the upper to middle part of the trigone, while patients with only short-term memory impairment had a lesion in the inferior supramarginal gyrus in common. Thus, damage to the periventricular white matter at the trigone may yield the phonemic paraphasia characteristic of conduction aphasia, while damage to the inferior part of the supramarginal gyrus may result in the impairment of short-term memory. We believe that as a part of the mechanisms of short-term memory and repetition, phonological information is processed in the primary auditory cortex and goes through the periventricular white matter to the inferior part of the supramarginal gyrus and is temporarily stored there.

Aged↗