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Biomedical subjects

S Ueno

Publications and source records attributed to S Ueno.

At least 181 records · Page 10Linked to original sources
PubMed1997

Trabeculotomy combined with phacoemulsification and implantation of an intraocular lens for the treatment of primary open-angle glaucoma and coexisting cataract.

BACKGROUND AND OBJECTIVE: The authors previously reported the usefulness of trabeculotomy ab externo for the treatment of primary open-angle glaucoma in adult patients. In an attempt to elucidate the long-term risk-to-benefit ratio of this surgical modality in combination with cataract surgery, the authors conducted a retrospective study of the surgical effects and complications of a triple procedure: phacoemulsification, implantation (of an intraocular lens), and trabeculotomy (PIT). PATIENTS AND METHODS: The authors conducted a retrospective study of patients treated with PIT at multiple hospitals. Intraocular pressure (IOP) and visual function data were obtained from patients after PIT as an initial surgical treatment in cases where antiglaucoma medications failed to resolve uncontrolled IOP (higher than 21 mm Hg). Included in this study were 96 eyes of 64 patients with primary open-angle glaucoma and coexisting cataract. The mean follow-up period was 22.6 +/- 14.7 months (range 3-56 months). RESULTS: In 94 (98%) of the 96 eyes, the IOP was well controlled, having achieved a level of 21 mm Hg or lower at the final examinations. The mean preoperative IOP of the 33 eyes that underwent the triple procedure using a single flap method (PIT-I) was 24.3 +/- 3.9 mm Hg, with an average of 2.1 +/- 1.1 medications. At the final examinations, the mean IOP had dropped to 16.0 +/- 1.2 mm Hg, with an average of 1.2 +/- 1.2 medications. The mean preoperative IOP of the 63 eyes that underwent the triple procedure using a double flap method (PIT-II) was 26.2 +/- 6.2 mm Hg, with an average of 1.9 +/- 1.2 medications. At the final examination, the mean IOP for this group was 15.6 +/- 2.9 mm Hg, with an average of 1.0 +/- 0.9 medications. CONCLUSION: The long-term results from this multicenter study showed that the triple procedure, PIT, can be useful and effective as an initial surgical treatment for open-angle glaucoma in glaucoma patients with coexisting cataract.

Adult↗
PubMed1996

Molecular cloning and expression of a novel peptide (LN1) gene: reduced expression in the renal cortex of lupus nephritis in MRL/lpr mouse.

A gene has been identified by mRNA differential display whose expression is reduced in the renal cortex of MRL/lpr mouse. The nucleotide sequence of the cDNA contains an open reading frame that encodes a protein of 338 amino acids (termed LN1). In situ hybridization showed that LN1 mRNA is present in glomeruli, and a 39 kDa protein was detected in the kidney by immunoblot. A human LN1 cDNA was also isolated, the deduced amino acid sequence of which is 78% identical to that of mouse LN1. Although the function of LN1 remains to be elucidated, its reduced expression may contribute to the pathogenesis of lupus nephritis.

Amino Acid Sequence↗
PubMed1996

Differences in the expression of GABA(A) receptors between functionally innervated and non-innervated granule neurons in neonatal rat cerebellar cultures.

We had earlier found that granule neurons in cultures of small explants of neonatal rat cerebellar cortex could be placed in two groups: cells in one group showed spontaneous synaptic activity and also had a large response to applications of 1 microM gamma-aminobutyric acid (GABA) while cells in the other lacked spontaneous activity and also showed much lower sensitivity to GABA [25]. For convenience, the more responsive cells will be termed A-type neurons, while the less responsive cells will be termed B-type. We have undertaken a comparison of the responses mediated by activation of GABA A receptors for the two types of neurons. A-type neurons have a larger maximal response to GABA (about 10 times that for B-type neurons), suggesting that they express more functional GABA(A) receptors. The concentration of GABA producing half-maximal activation of A-type neurons is somewhat less (12 mu M) than that for B-type neurons (41 microM), while the Hill coefficients are similar. Responses of both types of cell desensitize to prolonged applications of GABA. At a given concentration of GABA the responses of A-type neurons desensitize more rapidly than the responses of B-type neurons, indicating that the physiological properties of the receptors differ. Responses of A-type neurons are also potentiated to a significantly lesser extent by either chlordiazepoxide or alphaxalone than are the responses of B-type neurons, indicating that the pharmacological properties of the receptors differ. These data indicate that A-type and B-type granule neurons in our cultures express GABA(A) receptors which differ in number, physiological properties and pharmacological responsiveness. We have also confirmed the observation that almost all A-type neurons also show spontaneous synaptic currents, while almost no B-type neurons do.

Animals↗
PubMed1996

Induction of hepatocyte growth by intraportal infusion of HGF into beagle dogs.

Hepatocyte growth factor (HGF), originally identified as a potent mitogen for mature parenchymal hepatocytes, is a hepatotrophic factor involved in liver regeneration and is even essential for development of the liver. We report here that human recombinant HGF at a very low concentration and given intraportaly stimulated liver regeneration in dogs. In vitro, HGF dose-dependently stimulated DNA synthesis of primary cultured hepatocytes isolated from a dog. The maximal activity was twofold higher than that of epidermal growth factor, and insulin potentiated the mitogenic activity of HGF. When human recombinant HGF was infused through the portal vein into 30% partially hepatectomized dogs at 0.25 microg/kg body weight in order to directly target the liver, HGF stimulated DNA synthesis of hepatocytes and liver weight at 72 h after the operation; labeling indices in saline- and HGF-injected groups were 0.75 and 1.82%, respectively, and the liver weights in saline- and HGF-injected groups were 302 and 374 g, respectively. Since HGF exerts potent antihepatitis activity as well as mitogenic activity, these results indicate that intraportal administration of HGF may be particularly important to enhance liver regeneration and prevent the severe hepatic insufficiently after hepatic surgery.

Animals↗
PubMed1996

Mutant GTP cyclohydrolase I mRNA levels contribute to dopa-responsive dystonia onset.

We present a new Japanese family with hereditary progressive dystonia with marked diurnal fluctuation/dopa-responsive dystonia. The affected daughter and her asymptomatic father are heterozygous for a novel missense mutation that replaces His by Pro at codon 144 in the GTP cyclohydrolase I gene. Quantitative reverse transcription-polymerase chain reaction revealed a higher ratio of mutant/normal mRNA encoding GTP cyclohydrolase I in the patient. These results demonstrate the importance of mutant mRNA levels for phenotypic variability among cases with the same mutation.

Adult↗
PubMed1996

Perception of visual apparent movement and topographic analysis of related evoked potentials.

Most of the studies in long-range apparent movement have been concerned with the psychophysical properties in central vision. However, apparent movement in peripheral vision is not clearly understood. This study focuses on the properties of the perception of apparent movement between central and peripheral vision. The results show that judgements of apparent movement in central vision indicate high performance at less than 4 degrees of spatial separation, and that judgements in peripheral vision indicate high performance at greater than 4 degrees. Evoked potentials associated with long-range apparent movement were also measured, and topographic maps were constructed to evaluate the active areas corresponding to visual apparent movement. The topographic maps show that the central regions are activated above 300 msec after the onset of the second apparent-movement stimulation. The results suggest that visual apparent movement occurs in the visual association area, or at higher levels in the central nervous system.

Brain↗
PubMed1996

Human middle latency auditory evoked magnetic fields.

The magnetic equivalents of SN10, Po, Na, Pa, Nb and Pb (SN10m, Pom, Nam, Pam, Nbm, and Pbm) in short and middle latency auditory evoked potentials were measured with a 7-channel DC superconducting quantum interference device (SQUID). The sources of Pom, Nam, Pam, Nbm and Pbm responses were estimated to be located in the auditory cortex, while the source of SN10m was considered to be in a deeper part of the brain. In addition, the source of Pam was estimated to be in the vicinity of the moving N100m source. The source of Pbm was considered to be in a separate area, anterior to the source of Pam and N100m, which suggested that source of Pam was located in the primary auditory cortex, while the source of Pbm was located in the secondary auditory cortex. The source of N100m was considered to spread from the primary auditory cortex to the secondary auditory cortex.

Adult↗
PubMed1996

Source estimation of spontaneous MEG activity and auditory evoked responses in normal subjects during sleep.

This study focuses on source estimation of spontaneous MEG activity and auditory evoked responses during sleep. Sources of K-complexes and auditory evoked responses were investigated by magnetoencephalograph (MEG) and electroencephalograph (EEG) measurements, simultaneously. Sources of K-complexes during stage 2 sleep were investigated. The MEG results suggested that the sources of K-complexes can be modeled by two current dipoles. Dipoles for the K-complexes were estimated to be located 5 mm away from the sources of the N100 components of auditory evoked responses during wakefulness. Sources of auditory evoked responses during each sleep stage were also investigated to clarify the origins of the K-complex, the vertex sharp transient, and delta waves. Estimated dipoles for the N100 component for each sleep stage were estimated to be at slightly different locations in the auditory area. Based upon results of the MEG measurements and the EEG topographies, sources of the N330 component can be modeled by multiple current dipoles, which are seen to be distributed diffusely throughout the cerebral cortex.

Acoustic Stimulation↗
PubMed1996

Source models of sleep spindles using MEG and EEG measurements.

MEG measurements can detect brain sources that are difficult to detect with EEG measurements. The purpose of this study was to investigate models of sleep spindles using both MEG and EEG activities that had been recorded simultaneously. The components of magnetic fields perpendicular to the surface of the head were measured using a DC-SQUID with a first-derivative gradiometer. We propose three models for sleep spindles. In the first model, the source slides into the superficial region of the head so as to be perpendicular to it's surface, and with this model, the power spectrum of the MEG is decreased. In the second model, the source slides into the deeper structures, so that it is perpendicular to the surface. Here, the power spectra of both the MEG and EEG are decreased. The third model has source perpendicular to the surface, leaning and sliding into the deeper structures. Here, the power spectrum of the EEG is decreased but that of the MEG is not.

Brain↗
PubMed1996

MEG and EEG topography of frontal midline theta rhythm and source localization.

In this paper, we report on our study of frontal midline theta (Fm theta) activity in human subjects, recorded during mental processes such as arithmetic calculation. The Fm theta is a 6-7 Hz rhythmic wave with a duration of few seconds. The Fm theta activity is observed in the central region at the front of the head. EEGs and MEGs of Fm theta were measured simultaneously during mental calculation, and we analyzed these waveforms based on both topographic EEG maps and magnetic fields measurements. A single dipole simulated the EEG topography adequately, but there are many other dipole models which can generate a similar EEG pattern. It is difficult to estimate the source location of the Fm theta from the EEG topography alone because the EEG technique has a certain ambiguity associated with source estimation. Therefore, we considered the spatial relationships between the sources and the patterns of EEG and MEG that were simulated. Although it is not possible to obtain a unique solution for the source location of Fm theta from the EEG data alone, the simultaneous recording of MEGs from a large scalp area may result in an unambiguous solution. We therefore conclude that the simultaneous recording of both MEG and EEG data is more useful for accurate localization, than the EEG alone.

Brain↗
PubMed1996

Protective effect of vitamin E on chromium (VI)-induced cytotoxicity and lipid peroxidation in primary cultures of rat hepatocytes.

Pretreatment of primary cultures of rat hepatocytes with alpha-tocopherol succinate (vitamin E) for 20 h prior to exposure to K2Cr2O7 resulted in a marked decrease of chromium (VI)-induced cytotoxicity, as evaluated by the leakage of lactate dehydrogenase, without affecting cellular uptake and the subcellular distribution of chromium. The levels of chromium (VI)-induced lipid peroxidation, as monitored by malondialdehyde formation, were also inhibited by pretreatment with the vitamin. Pretreatment with vitamin E normalized the levels of nonenzymatic antioxidants such as glutathione and vitamin C suppressed by dichromate, and caused a distinct accumulation of vitamin E in hepatocytes. However, vitamin E pretreatment did not affect the activities of enzymatic antioxidants including glutathione reductase, superoxide dismutase, and catalase suppressed by dichromate. These results indicate that the protective effect of vitamin E against chromium (VI)-induced cytotoxicity as well as lipid peroxidation, may be associated more with the level of nonenzymatic antioxidants than the activity of enzymatic antioxidants.

Animals↗
PubMed1996

Exogenous hepatocyte growth factor markedly stimulates liver regeneration following portal branch ligation in dogs.

Portal branch ligation (PBL) or embolization prior to extensive hepatectomy has been employed to increase the functional reserve of the remaining liver. This study investigated the effects of human recombinant hepatocyte growth factor (rh-HGF) on liver regeneration following PBL in dogs. Beagle dogs were subjected to PBL and were divided into two groups, a control group (n = 11) without rh-HGF and a treated group (n = 12) receiving postoperative rh-HGF at 250 ng/kg via the portal vein. Dogs were killed 72 h or 14 days following PBL. We studied the changes in serum HGF level, DNA synthesis of the liver, hepatocyte size, liver weight, and liver function tests. In the HGF group, the ratio of whole liver weight to body weight increased significantly, and both ligated and nonligated lobes showed marked increases in weight. The nonligated lobes in the HGF group showed significant increases in both DNA synthesis and hepatocyte size. Moreover, ligated lobes in the HGF group showed an increase in DNA synthesis without hypertrophy compared with the control group. Administration of rh-HGF did not significantly affect liver function tests. Ligation of the portal branch supplying the portion of liver to be resected, coupled with the administration of rh-HGF, is a useful strategy to increase hepatic reserve in advance of major hepatectomy.

Animals↗
PubMed1996

Relationship of (CAG)nC configuration to repeat instability of the Machado-Joseph disease gene.

The mutation responsible for Machado-Joseph disease (MJD) has been identified as an expansion of a CAG trinucleotide repeat in a novel gene on chromosome 14q32.1. The CAG repeat tract is followed by C or G, and alleles are thereby divided into two types on the basis of molecular configuration, (CAG)nC and (CAG)nG. We have studied the relationship between the repeat length and the configuration in 38 patients from 28 Japanese families with MJD, and 31 unrelated normal Japanese subjects. The CAG repeat length in 100 normal alleles ranged from 13 to 37 repeats, while 38 MJD patients had one expanded allele with 64 to 84 repeats. Surprisingly, the expanded alleles had exclusively the (CAG)nC configuration, while both (CAG)nC and (CAG)nG were seen in normal alleles from MJD and control subjects. Furthermore, in normal alleles, the CAG repeat tract was significantly longer in (CAG)nC than in (CAG)nG. These findings suggest that the (CAG)nC configuration is related to repeat instability of the MJD gene.

Alleles↗
PubMed1996

Corticospinal direct response to transcranial magnetic stimulation in humans.

The corticospinal motor evoked potential (MEP) response to transcranial magnetic stimulation of the motor cortex was investigated in comparison with the direct (D) response to electrical stimulation of the exposed motor cortex from the spinal epidural space in 7 neurologically normal patients during brain tumor surgery. The D response during operation was obtained by transcranial magnetic stimulation of the scalp over the areas of the cerebral motor cortex, the hand or arm areas. The magnetic induced D response showed a conduction velocity of 50.5-72.7 m/sec and was resistant to anesthesia and unaffected by muscle relaxants and tolerant to high frequency (500 Hz) paired magnetic stimulus, and the latencies of magnetic MEPs corresponded to those with direct electrical stimulation. Thus, recordings of the D response by transcranial magnetic stimulation are useful for not only identifying the location of the motor cortex during intracranial surgery but also for non-invasive recording of pyramidal tract activity during extracranial surgery under general anesthesia.

Aged↗
PubMed1996

Implication of ATP receptors in brain functions.

The possible implication of P2-purinoceptors in brain functions is reviewed. Involvement of P2-purinoceptors in memory and learning (Section 2) is suggested by ATP release from hippocampal slices [Wieraszko, A., Goldsmith, G. and Seyfried, T. N. (1989) Brain Res. 485, 244-250], induction of fast synaptic currents in cultured hippocampal neurons [Inoue, K., Nakazawa, K., Fujimori, W. and Takanaka, A. (1992a) Neurosci. Lett. 134, 294-299] and long-lasting enhancement of the population spikes [Wieraszko, A. and Seyfried, T. N. (1989) Brain Res. 491, 356-359; Nishimura, S., Mohri, M., Okada, Y. and Mori, M. (1990) Brain Res. 525, 165-169; Fujii, S., Kato, H., Furuse, H., Ito, K., Osada, H., Hamaguchi, T. and Kuroda, Y. (1995) Neurosci, Lett. 187, 130-132], as well as ATP release on glutamate stimulation to evoke an increase in intracellular Ca2+ in hippocampal cells [Inoue, K., Koizum, S. and Nakazawa, K. (1995) NeuroReport 6, 437-440]. Moreover, mRNAs for certain types of P2x-purinoceptors are present in the hippocampus [Collo, G., North, R. A., Kawashima, E., Merlo-Pich, E., Neidhart, S., Surprenant, A. and Buell, G. (1996) J. Neurosci. 16, 2495-2507]. It is likely, therefore, that ATP may be involved in modulation of synaptic efficiency in the hippocampus. The implication of ATP in schizophrenia is suggested by the fact that antipsychotic drugs inhibit ATP-evoked responses in PC12 cells [Koizumi, S., Ikeda, M., Nakazawa, K., Inoue, K., Ito, K. and Inoue, K. (1995b) Biochem. Biophys. Res. Commun. 210, 624-630] without blocking the action of dopamine D2 receptors. Involvement of P2-purinoceptors in Sections 4 ("Pain and cognition") and 5 ("Central regulation of the autonomic system") are also discussed.

Animals↗
PubMed1996

Prosaposin facilitates sciatic nerve regeneration in vivo.

Prosaposin, a multifunctional protein, is the precursor of saposins, which activate sphingolipid hydrolases. In addition to acting as a precursor for saposins, prosaposin has been shown to rescue hippocampal CA1 neurons from lethal ischemic damage in vivo and to promote neurite extension of neuroblastoma cells in vitro. Here we show that prosaposin, when added to a collagen-filled nerve guide after sciatic nerve transection in guinea pigs, increased dramatically the number of regenerating nerve fibers within the guide. To identify the target neurons of prosaposin during peripheral nerve regeneration, we determined the degree of atrophy and chromatolysis of neurons in the spinal anterior horn and dorsal root ganglia on the prosaposin-treated and untreated side. The effect of prosaposin on large spinal neurons and small neurons of the dorsal root ganglion was more conspicuous. Subsequent immunohistochemistry demonstrated that the atrophy of cholinergic large neurons in the anterior horn is prevented to significant extent by prosaposin treatment. These findings suggest that prosaposin promotes peripheral nerve regeneration by acting on alpha-motor neurons in the anterior horn and on small sensory neurons in the dorsal root ganglion. The present study raises the possibility of using prosaposin as a tool for the treatment of peripheral nerve injuries.

Animals↗
PubMed1996

A hydrophilic peptide comprising 18 amino acid residues of the prosaposin sequence has neurotrophic activity in vitro and in vivo.

Prosaposin, a 517-amino-acid glycoprotein, not only acts as the precursor of saposin A, B, C, and D but also possesses neurotrophic activity to rescue hippocampal CA1 neurons from ischemic damage in vivo and to promote neurite extension of neuroblastoma cells in vitro. Recently, the trophic activity of prosaposin on human neuroblastoma cells has been shown to reside in the NH2-terminal hydrophilic sequence (LIDNNRTEEILY) of the human saposin C. Here we show that prosaposin, saposin C, and a peptide comprising the 18-amino-acid sequence (18-mer peptide; LSELIINNATEELLIKGL) located in the NH2-terminal hydrophilic sequence of the rat saposin C-domain promoted survival and neurite outgrowth of cultured rat hippocampal neurons in a dose-dependent manner. Moreover, infusion for 7 days of the 18-mer peptide into the lateral ventricle of gerbils, starting either 2 h before or immediately after 3 min of forebrain ischemia, protected ischemia-induced learning disability and hippocampal CA1 neuronal loss. Thus, we ascribe the in vitro and in vivo trophic actions of prosaposin on hippocampal neurons to the linear 18-mer sequence and raise the possibility that this peptide can be used as an agent for the treatment of forebrain ischemic damage.

Amino Acid Sequence↗