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Biomedical subjects

Y Hatanaka

Publications and source records attributed to Y Hatanaka.

At least 55 records · Page 3Linked to original sources
PubMed1999

Different expression patterns of nitric oxide synthase isozymes in various gynecological cancers.

The expression of nitric oxide synthase (NOS) in human gynecological cancers, including ovarian cancers, uterocervical cancers, and endometrial cancers for example, was examined by the reverse transcriptase/polymerase chain reaction, coupled with Southern hybridization and by immunohistochemistry. Nitric oxide synthase II (NOS II), an inducible form, was expressed in more than 90% of the cancers. Nitric oxide synthase I (NOS I), a neuronal form, was expressed in 58% of all the ovarian cancers, in which the serous type is found more frequently (5 out of 7) than the mucinous type (2 out of 6), and in all clear-cell cancers. The frequency of NOS I expression in uterocervical cancers and endometrial cancers was relatively low. Nitric oxide synthase III (NOS III), an endothelial form, was detected in 25% of ovarian and 33% of endometrial cancers, while no expression was detected in uterocervical cancers. In terms of cancer types, all clear-cell adenocarcinomas and most of the serous-type adenocarcinomas expressed both NOS I and NOS II, while most uterine squamous carcinomas and endometrial adenocarcinomas expressed only NOS II. However, there was no correlation between the frequency of NOS expression and patients' age or the clinical stage of the disease. Since NO increases vascular permeability and blood flow, the high frequency of NOS expression in gynecological cancers may serve to stimulate and promote tumor growth.

Blotting, Southern↗
PubMed1999

Asymmetric reduction of hydroxyacetone to propanediol in immobilized halotolerant microalga Dunaliella parva.

Cells of the halotolerant microalga Dunaliella parva immobilized in calcium-alginate gel showed morphological characteristics and photosynthetic activity similar to those of free cells. The photosynthetic activity in immobilized cells fell only about 20% during 2 weeks incubation at 5 degrees C in the light. The asymmetric reduction of hydroxyacetone to (R)-propanediol was first examined in batch reactions with both free and immobilized cells. Since the activity of immobilized cells was as high as that of free cells, the optimum conditions for the column reactor were investigated using immobilized cells. The productivity of propanediol in immobilized cells increased in proportion to increases in the light intensity, suggesting that NADPH regenerated through photosynthesis was used for the asymmetric reduction. Electron microscopic observation of thin sections of immobilized cells after the reaction suggested that NADPH used for asymmetric reduction in the dark was produced through the metabolism of starch granules. The use of a CaCO3-free medium in the column reactor markedly prolonged the period of reductive activity and photosynthesis.

Journal Article↗
PubMed1999

Novel genes expressed in the developing medial cortex.

Two cDNAs, M1 and M2, recently isolated by the differential display method from embryonic rat cerebral hemisphere were characterized and their patterns of spatiotemporal expression analysed in developing rat forebrain by in situ hybridization histochemistry and correlative immunocytochemistry. Neither gene bears any sequence homology to other known genes. Both genes are particularly expressed in medial regions of the cerebral hemisphere and M2 in the roof of the adjacent diencephalon. M1 expression is highly localized and confined to the neuroepithelium of the hippocampal rudiment from embryonic day (E) 12 onward. Its location corresponds to the fimbrial anlage, and immunocytochemical localization of M1 protein indicates its expression in radial glial cells. M2 expression at E12 is more extensive in the medial cerebral wall, extending into the preoptic region and beyond the hippocampus into dorsal hemisphere and into the dorsal diencephalon, with caudal extension along the dorsal midline and in the zona limitans intrathalamica. Later, M2 expression is found in association with the corpus callosum, hippocampal commissure, fimbria, optic nerve, stria medullaris, mamillothalamic tract and habenulopeduncular tract. M1 and M2 expression domains corresponding to the locations of fiber tracts are present prior to the arrival of the earliest axons, as identified by neuron specific markers. These findings suggest M1 and/or M2 genes are involved in early regional specification of the hippocampus and related structures in paramedian regions of the forebrain, and that cell populations expressing these genes in advance of developing axonal pathways may be involved in the early specification of tract location.

Animals↗
PubMed1999

Autosomal dominant muscle cramp syndrome in a Japanese family.

OBJECTIVES: To identify the clinical, electrophysiological, histological, and genetic characteristics of a Japanese family with a muscle cramp syndrome. METHODS: Fourteen patients (eight men, six women) were studied in four generations of a single family. Electrophysiological examinations were performed in four cases and muscle and nerve biopsies were performed on the propositus. RESULTS: The mode of inheritance seemed to be autosomal dominant. The cramps occurred during both exertion and at rest, and during sleep. Electromyographic examination indicated a neurogenic aetiology. There was a decreased number of large myelinated fibres in the sural nerve, and fibre type grouping in the quadriceps femoris muscle biopsy. CONCLUSIONS: The autosomal dominant muscle cramp syndrome in this family is probably caused by a polyneuropathy.

Aged↗
PubMed1999

N18 in median somatosensory evoked potentials: a new indicator of medullary function useful for the diagnosis of brain death.

OBJECTIVES: To record N18 in median somatosensory evoked potentials (SEPs) for deeply comatose or brain dead patients and to demonstrate the usefulness of N18 for the diagnosis of brain death in comparison with auditory brain stem responses (ABRs) and P13/14 in median SEPs, which have been conventionally used as complementary tests for the diagnosis of brain death. METHODS: Subjects were 19 deeply comatose or brain dead patients. Thirteen recordings were performed in deeply comatose but not brain dead conditions, and 12 recordings were performed in brain death. N18 was evaluated in the CPi-C2S lead (or other scalp-C2S leads) to obtain a flat baseline. RESULTS: N18 was preserved in 12 of 13 non-brain dead comatose recordings whereas it was completely lost for all of the 12 brain death recordings. P13/14 in median SEPs was preserved for all the comatose recordings, whereas apparent P13/14-like potentials, usually of low amplitude, were seen in nine of 12 brain death recordings-that is, frequent false positives. The ABRs already showed features which were characteristic for brain death (loss of components other than wave 1 or small wave 2) for four comatose recordings, in three of which N18 was preserved. The last result not only corresponds with the fact that ABRs can evaluate pontine and midbrain functions and not medullary function, but further supports the medullary origin of N18. In the four patients followed up for the course of progression from coma to brain death, N18s preserved in normal size during the comatose state were completely lost after brain death was established. CONCLUSIONS: The N18 potential is generated by the cuneate nucleus in the medulla oblongata in the preceding studies. N18 is suggested to be a promising tool for the diagnosis of brain death because there were no false positives and rare false negatives in the present series for detecting the remaining brain stem function.

Adult↗
PubMed1999

Identification of photolabeled peptides for the acceptor substrate binding domain of beta 1,4-galactosyltransferase.

We successfully applied a carbene-generating N-acetylglucosamine derivative carrying a biotinyl group to the radioisotope-free identification of peptides within bovine UDP-galactose: N-acetylglucosamine beta 1,4-galactosyltransferase (GalT, EC 2.4.1.38) catalytic domain. Owing to the low yield of cross-linking, conventional photoaffinity labeling experiments usually encounter a thorny problem in attempting to isolate labeled components from very complex mixtures. A biotin tag introduced with our photoaffinity probe enabled us to separate the photolabeled protein from a large amount of coexisting unlabeled GalT. The introduction of biotin was also useful for the radioisotope-free detection of a labeled protein based on a highly sensitive chemiluminescent technique. We developed a novel poly(vinylidene difluoride) membrane for the identification of labeled peptides in a simple dot blot assay. Using this membrane, we successfully identified biotinyl peptides among a number of HPLC separated fragments derived from the protease digestion of photolabeled GalT proteins. The sequence analysis revealed that the biotin tag was incorporated within a tryptic GalT fragment of Y197-R208. Our approach yields, for the first time, information on the acceptor substrate binding-site fragment in this enzyme, that has been difficult to obtain using other approaches. These data are consistent with previous suggestions concerning the GalT acceptor site and clearly demonstrate the effectiveness of our approach for rapid identification of photolabeled peptides.

Amino Acid Sequence↗
PubMed1999

[Vitamin B1 deficiency polyneuropathy presenting homolateral imitative synkinesia].

We report a 56-year-old woman with vitamin B1 polyneuropathy, showing bilateral homolateral imitative synkinesia. Needle electromyogram revealed neurogenic changes, and the amplitude of muscle action potential was low. Sural nerve biopsy showed a marked loss of myelinated fibers, and severe axonal degeneration was diagnosed. Spinal and brain MRI revealed no abnormalities. In the literature, these synkinesias were observed in patients with parietal, thalamic, and basal ganglia lesions and with chorea. We suggest that this synkinesia is the release phenomenon in the circuit of the motor programming system due to the disturbance of peripheral nerve or funiculus posterior.

Electromyography↗
PubMed1998

Reactive oxygen species enhances the induction of inducible nitric oxide synthase by sphingomyelinase in RAW264.7 cells.

The sphingomyelin pathway, activated by stimuli, such as inflammatory cytokines, results in the formation of ceramide, a second messenger molecule. The purpose of the present study was to examine the mechanism by which macrophage-type nitric oxide synthase (NOS II) is induced by stimulation of the sphingomyelin pathway. When RAW264.7 cells were incubated with sphingomyelinase (SMase), nitrite production, NOS II activity, and NOS II mRNA were increased in a dose-dependent manner. Sphingosine, dihydrosphingosine, N-acetylsphingosine (C2-ceramide), and N-acylsphingosine (natural ceramide) had no effect on nitrite production, suggesting that signal molecules other than these were concomitantly produced by SMase treatment and required for NOS II induction. We then investigated the possible involvement of intracellular reactive oxygen species (ROS) in gene induction. SMase treatment increased the level of intracellular ROS, as assessed by flow cytometric analysis using a ROS-sensitive dye, dichlorofluorescin diacetate. Antioxidants, such as N-acetyl-l-cysteine and alpha-tocopherol, inhibited gene induction as well as nitrite production by SMase. These results suggest that activation of the sphingomyelin pathway induces gene expression and that the elevated ROS were somehow involved in this process.

Acetylcysteine↗
PubMed1998

Early region-specific gene expression during tract formation in the embryonic rat forebrain.

Expression profiles of two recently isolated cDNA fragments, M1 and M2, expressed in the medial telencephalon, were analyzed in developing rat forebrain by in situ hybridization histochemistry and correlative immunocytochemistry. M1 expression was observed in the most ventral portion of the hippocampal rudiment with a sharp dorsal boundary, from embryonic day (E) 12 onward. Its location corresponded to the fimbrial anlage. As the fimbria developed, segregated expression of M1 and neuron-specific class III beta-tubulin or GAP-43 became apparent, suggesting that part of the neuroepithelium producing fimbrial neuroglia expresses M1. M2 expression in the E12 telencephalon was confined to part of the medial cerebral wall, including the presumptive preoptic region and hippocampus, with a diffuse dorsal boundary. At the same stage, M2 expression also occurred in part of the dorsal diencephalon adjacent to the M2-positive telencephalic region, with caudal extension along the dorsal midline, and in the zona limitans intrathalamica. M2 expression domains lacked neuron-specific class III beta-tubulin immunoreactivity. During later stages, M2 expression was found in association with the corpus callosum, hippocampal commissure, fimbria, optic nerve, stria medullaris, tract of the zona limitans, and habenulopeduncular tract. In most cases, M2 expression was detected in regions corresponding to fiber tracts prior to arrival of the earliest axons, which could be detected by TAG-1- or GAP-43 immunohistochemistry. These findings suggest that specialized cell populations express M1 and/or M2 genes in paramedian regions of the forebrain in advance of developing axonal pathways and may be involved in early specification of tract location and differentiation of tract neuroglia.

Animals↗
PubMed1998

Cell-surface biotinylation of GLUT4 using bis-mannose photolabels.

New cell-impermeant bis-mannose photolabels have been developed with biotinyl groups attached to 4-(1-azi-2,2,2-trifluoroethyl)-benzoyl-1, 3-bis(d-mannos-4-yloxy)-2-propylamine (ATB-BMPA) by either a polyethoxy spacer (Bio-ATB-BMPA) or an additional hexanoic acid spacer (Bio-LC-ATB-BMPA). The half-maximal inhibition constants, Ki values, for inhibition of glucose transport activity in insulin-stimulated rat adipocytes were determined to be 359+/-10 and 273+/-28 microM for Bio-ATB-BMPA and Bio-LC-ATB-BMPA, respectively. These values are similar to those previously reported for the non-biotinylated compound ATB-BMPA. Following UV-irradiation-induced cross-linking of the biotinylated photolabels to rat adipocytes, the biotinylated glucose transporter isoform 4 (GLUT4) could be detected by non-radioactive and radioactive methods that utilized the interaction with streptavidin. Biotinylated GLUT4 from 1-2 microg of adipose cell membranes, precipitated onto magnetic streptavidin beads, could be sensitively and quantitatively detected using an electrochemiluminescent assay method. This utilized a ruthenium-tagged anti-GLUT4 antibody that on excitation at an electrode generated an electrochemiluminescent signal in an ORIGEN analyser. Alternatively, surface-biotinylated GLUT4 could be easily, but less sensitively, detected in streptavidin agarose precipitates which were analysed by conventional GLUT4 Western blotting. Data obtained using the non-radioactive methods compared favourably with those using tritiated versions of the biotinylated probes. Insulin treatment of adipocytes increased the levels of signals from surface biotinylated GLUT4 by approximately 10-fold or approximately 20-fold, respectively, when the electrochemiluminescent or the Western blot detection methods were used and these signals were blocked by cytochalasin B.

Adipocytes↗
PubMed1998

Expression of substance P receptor in the substantia nigra.

Since the substantia nigra receives abundant substance P innervations but lacks clear evidences about a presence of substance P receptors, expressions for mRNA and protein of substance P receptors were investigated in the rat to resolve this mismatch. Expression levels of substance P receptors mRNA in the substantia nigra pars compacta and reticulata were 37.7 and 24.1% of those in the striatum, respectively, by reverse transcription-polymerase chain reaction (RT-PCR). Substance P receptors mRNA was found in dopamine neurons of the substantia nigra pars compacta by single cell RT-PCR. Ca. 90% of dopamine neurons in the substantia nigra pars compacta were immunoreactive to anti-substance P receptor antibody in the colchicine treated rats. These are the first direct evidence for the existence of substance P receptors in dopamine neurons of the substantia nigra pars compacta.

Animals↗
PubMed1998

The effects of transjugular intrahepatic portosystemic shunt on portal hypertensive gastropathy.

In addition to variceal bleeding, haematemesis may occur due to haemorrhagic gastritis in patients with portal hypertension. This has been known as portal hypertensive gastropathy (PHG). We have evaluated the effects of the transjugular intrahepatic portosystemic shunt (TIPS) on portal venous pressure (PVP) and endoscopic gastric mucosal changes observed in patients with portal hypertension. We performed TIPS in 12 patients with complications due to portal hypertension as follows: variceal bleeding in nine patients (bleeding from oesophageal varices in seven and gastric varices in two), refractory ascites in three and haemorrhage from severe PHG in one. Endoscopic examinations were performed before and after TIPS for all patients. Changes of PVP and gastric mucosal findings on endoscopy were analysed. Before TIPS, PHG was seen in 10 patients. Portal venous pressure decreased from an average of 25.1+/-8.8 to 17.1+/-6.2 mmHg after TIPS (P<0.005). On endoscopy, PHG improved in nine of 10 patients. Oesophagogastric varices improved in eight of 11 patients. In one patient with massive haematemesis, haemorrhage from severe PHG completely stopped after TIPS. Because TIPS effectively reduced PVP, this procedure appeared to be effective for the treatment of uncontrollable PHG.

Endoscopy, Gastrointestinal↗
PubMed1998

Effects of mannitol and glycerol on cerebral energy metabolism in gerbils.

OBJECTIVES: To evaluate the effects of infusion with hyperosmolar solutions, mannitol and glycerol on the recovery of cerebral energy metabolism during ischemia and reperfusion in the gerbil brain. MATERIALS AND METHODS: Sequential changes in cerebral energy metabolism following 90-min ischemia and up to 8 h after reperfusion were measured in 15 gerbils using 31P nuclear magnetic resonance (NMR) spectroscopy after 60-min infusion of 10% glycerol (0.5 g/kg; n=5), or 20% mannitol (1.0 g/kg; n=5), and compared with those gerbils receiving with saline (n=5). Gerbils were anesthetized by intraperitoneal injection of pentobarbital. Forebrain ischemia was induced by clipping of bilateral common carotid arteries for 90 min and reperfused. NMR spectroscopy was measured by a 6.34-Tesla JEOL spectrometer, before administration, 2, 4, 6, and 8 h after 90-min ischemia and reperfusion. Areas of inorganic phosphate (Pi), phosphocreatine (PCr), and beta-ATP peaks were measured to calculate parameters of cerebral energy metabolism, i.e., PCr/Pi and beta-ATP/Pi ratios. Intracellular pH (pHi) was calculated from chemical shifts of Pi relative to PCr. RESULTS: PHi was higher in the mannitol group than in the glycerol and saline groups (P<0.05) 2 h after reperfusion. PCr/Pi ratio was higher 2, 4, and 8 h after reperfusion (P<0.01, P<0.05, P<0.01) in the mannitol group; and 6 h after reperfusion (P<0.05) in the glycerol group; than in the saline group. Beta-ATP/Pi ratio was higher 2 and 8 h after reperfusion (P<0.05) in the glycerol group; and 2 h after reperfusion (P<0.01) in the mannitol group, than in the saline group. CONCLUSIONS: The mannitol group had improved pHi higher than the glycerol group 2 h after reperfusion (P<0.05), while the glycerol group had improved beta-ATP/Pi ratio higher than the mannitol group 6 h after reperfusion (P<0.05). Both mannitol and glycerol groups had improved parameters of cerebral energy metabolism during ischemia and up to 8 h after reperfusion in the gerbil brain.

Adenosine Triphosphate↗
PubMed1998

[Bilateral homonymous hemianopsia with atrial fibrillation].

We encountered an 80-year-old man with sudden bilateral visual disturbance. When he was admitted to the hospital, his blood pressure was 138/70 mmHg, and an ECG revealed atrial fibrillation. Neurological examination showed only bilateral homonymous hemianopsia with no nystagmus or impairment of eye movement. He did not have paralysis cerebellar ataxia, or speech disturbance. Therefore, there was no evidence of obstruction of the thalamogeniculate or thalamoperforating artery. Magnetic resonance imaging of the brain showed cerebral infarctions in both occipital lobes. Perimetry showed bilateral homonymous hemianopsia; the left side of the macula was spared. The lack of neurological deficit other than bilateral homonymous hemianopsia indicates that only the right and left cortical branches of the posterior cerebral artery were occluded.

Aged↗
PubMed1998

[A recovered case of SLE with central nervous system involvement who relapsed presenting new symptoms associated with development of serum anti-Sm antibody].

A rare SLE patient with central nervous system involvement (CNS-SLE) who relapsed presenting new symptoms associated with the development of serum anti-Sm antibody and was then successfully treated with cyclophosphamide (CY) pulse therapy is presented here. A 47-years old housewife was admitted to Kushiro City General Hospital because of fever, limb erythema and drowsy consciousness in September 1995. On the basis of convulsion, proteinuria, leukopenia, thrombopenia, serum positive tests for both anti-nuclear antibody and anti-SSA antibody and low complement levels, as well as elevations of IgG index and IL-6 in the cerebrospinal fluid (CSF), she was diagnosed as having CNS-SLE. Serum tests for anti CL-beta 2 GPI antibody and lupus anticoaglant was negative. Serum test for HBs antigen was positive. She was treated successfully with methylprednisolone (mPSL) pulse therapy and plasma exchange (PE). Prednisolone was gradually tapered to the dosage of 17.5 mg per day and she was discharged in April 1996. She was re-admitted because of fever, an exacerbation of skin eruption and arthralgia in October 1996. Serum anti-Sm antibody was found to be positive. mPSL pulse therapy was not effective. On the basis of hallucination and elevations of IgG index and IL-6 in the CSF, a diagnosis of relapsed CNS-SLE was made. However the level of IFN-alpha in the CSF was normal. Although PE was not effective, CY pulse therapy was markedly effective.

Autoantibodies↗
PubMed1997

Osmotic stress induces a phase transition from interdigitated gel phase to bilayer gel phase in multilamellar vesicles of dihexadecylphosphatidylcholine.

We have investigated the effects of poly(ethylene glycol) (PEG) on the structure and phase behavior of multilamellar vesicles of dihexadecylphosphatidylcholine (DHPC-MLVs) using an X-ray diffraction method. At low concentrations of PEG-6K (MW = 7500), DHPC-MLVs were in an interdigitated gel (L(beta)I) phase, a gel phase with interdigitated hydrocarbon chains. At around 24% (w/v) PEG 6K, a phase transition from the L(beta)I phase to a bilayer gel phase occurred in the DHPC-MLVs, and above this concentration, they were in a bilayer gel phase. On the other hand, ethylene glycol (EG), the monomer of PEG, did not induce this phase transition in the DHPC-MLVs. A mechanism of this phase transition is proposed and discussed; a decrease in the repulsive interaction between the head groups of the phospholipids in the bilayer gel phase with an increase in PEG concentration, which is due to a decrease in the cross-sectional area of the head group region by osmotic stress, may be the main reason for this phase transition.

Journal Article↗
PubMed1997

Early molecular specification in the hippocampal rudiment: isolation of genes expressed in a region-specific manner in the embryonic telencephalon.

During development, the structure of the telencephalon is dramatically transformed by region-specific proliferation and differentiation of neuroepithelial cells. To understand mechanisms of morphogenesis in the telencephalon, a search was made for genes expressed in a region-specific manner in the dorsal telencephalon of embryonic rats. Dorso-lateral and dorso-medial portions of the telencephalon were taken from rat fetuses on embryonic day (E) 13. Genes expressed in each portion were compared by a modified differential display method. Among more than 4000 cDNA fragments, four fragments termed M1, M1', M2 and M3 were found only after amplification of cDNAs derived from the dorso-medial portion of the telencephalon. Nucleotide sequence and Northern blot analyses showed that M1 and M1' were identical and that M2 and M3 were related genes. In situ hybridization revealed that M1 was expressed in a restricted portion of the hippocampal rudiment with a sharp boundary. M2 and M3 were expressed in the hippocampal rudiment with a more diffuse boundary than that of M1. Expression of M2 and M3 was also found in the most anterior part of the medial diencephalon with a caudal extension along the dorsal midline. These results suggest that at least two types of molecular specification occur in the dorso-medial telencephalon, contributing to the construction of the hippocampal elements during early stages of development.

Animals↗