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Biomedical subjects

S Ueno

Publications and source records attributed to S Ueno.

At least 199 records · Page 11Linked to original sources
PubMed1996

Japanese triplets with cerebrotendinous xanthomatosis are homozygous for a mutant gene coding for the sterol 27-hydroxylase (Arg441Trp).

We present the first case of triplets with cerebrotendinous xanthomatosis (CTX). A C-to-T base change identified in the genomic DNA and cDNA encoding the sterol 27-hydroxylase led to replacement of arginine by tryptophan at position 441 (Arg441Trp) in the triplets. The triplets were homozygous and their mother was heterozygous for this mutant gene. The triplets exhibited an identical phenotypic expression, which was different from that of a sporadic CTX case with the same mutation.

Adult↗
PubMed1996

Decrease of the D3 dopamine receptor mRNA expression in lymphocytes from patients with Parkinson's disease.

We investigated the dopamine receptor (DAR) mRNA expression in peripheral blood lymphocytes from 45 patients with Parkinson's disease (PD) and 21 age-matched controls using the quantitative reverse transcription and polymerase chain reaction method. Beta-actin mRNA was used as an internal control to evaluate the relative expression level of the DAR mRNA. There was a statistically significant decrease of the D3 dopamine receptor (D3R) mRNA expression in PD patients compared with that in controls. There was no change in expression of the D5 dopamine reception mRNA in PD patients. A further binding study showed reduction of the D3R binding sites in PD lymphocytes. The decrease of the D3R mRNA expression correlated with the degree of clinical severity in PD patients.

Actins↗
PubMed1996

Cloning of mRNA sequences for two antibacterial peptides in a hemipteran insect, Riptortus clavatus.

Escherichia coli injection rapidly induced bactericidal activity in the hemolymph of a hemipteran insect, Riptortus clavatus. This activity reached its maximum at 9 hr after injection and thereafter declined slowly. Two types of cDNA clones involved in this response were isolated by differential screening. The predominant type encoded for an open reading frame of 678 amino acids, which consisted of fourteen tandem repeats. Each repeat was rich in charged residues and had a proline-rich region which had striking sequence similarities to proline-rich antibacterial peptides from other insect species, indicating these clones encode a multipeptide precursor of antibacterial peptides. The other type encoded for a glycine-rich peptide similar to a known antibacterial peptide as well. Northern blot analyses revealed rapid induction of mRNAs corresponding to these clones after the injection. To our knowledge, this is the first report on the mRNA sequences of antibacterial peptides of hemimetabolous insects, and the second report on the occurrence of multipeptide precursor structure in insect antibacterial peptides.

Animals↗
PubMed1996

Hepatic hemodynamics in a patient with nodular regenerative hyperplasia.

Nodular regenerative hyperplasia of the liver is an uncommon condition. Approximately 50% of these patients develop portal hypertension. Few previous reports document the site of increased resistance to blood flow within the liver in this disorder. We measured Doppler waveform patterns of the right hepatic vein by pulsed Doppler ultrasonography and portal, wedged hepatic, and free hepatic venous pressure by intravenous catheter before and after splenectomy in a 47-yr-old woman with nodular regenerative hyperplasia who presented with portal hypertension and pancytopenia. Nodular regenerative hyperplasia was histologically confirmed. Pre- and postoperative measures indicated a marked difference between wedged hepatic venous pressure and free hepatic venous pressure, whereas there was little difference between portal venous pressure and wedged hepatic venous pressure. Doppler waveform patterns of the right hepatic vein showed an unclear pulsatile flow pattern with a decreasing reversed phase. The above data suggest that portal hypertension in nodular regenerative hyperplasia is primarily sinusoidal, similar to that seen with cirrhosis.

Female↗
PubMed1996

[Familial amyotrophic lateral sclerosis showing variable clinical courses with (Leu84-->Val) mutation of Cu/Zn superoxide dismutase].

A family with autosomal-dominant amyotrophic lateral sclerosis with histopathological confirmation on autopsy was described. A 42-year-old female proband showed the signs and symptoms only in the lower limbs characteristic of lower motor neuron involvement at the onset. ALS had been diagnosed in other five members in three generations of her family. The mean +/- SD age of onset of the disease was 42.5 +/- 9.3 years with a range of 30 to 51 years. The mean +/- SD duration of the disease (n = 5, excluding the proband) was 56 +/- 70 months with a range of 7 to 180 months. Molecular genetic studies showed a T-to-G transversion that results in the substitution of valine for leucine84 in exon 4 of the Cu/Zn superoxide dismutase (SOD) gene on chromosome 21 in a proband. This mutation is identical to that found in the Japanese family with autosomal-dominant ALS characterized by short duration of the disease, within 1.5 years, in all the affected family members. Therefore, the clinical phenotype, especially the duration of the disease seems to be highly variable even in the families with the identical mutation of the Cu/Zn SOD gene.

Adult↗
PubMed1996

Endogenous subunits can cause ambiguities in the pharmacology of exogenous gamma-aminobutyric acidA receptors expressed in human embryonic kidney 293 cells.

The physiological and pharmacological properties of GABAA receptors have been studied extensively after the expression of subunits in non-neural cells. Many of these studies have used the human embryonic kidney cell line HEK 293. We examined the properties of subunits that result in the expression of low levels of functional receptors and found that the properties of the gamma-aminobutyric acid (GABA)-elicited responses in transfected HEK 293 cells differ from expectations based on previous work and are consistent with the idea that the expressed receptors do not necessarily contain the expected subunits. In particular, expression of a mutated beta 2 subunit [beta 2(Y205S)] in combination with alpha 1 and gamma 2L results in cells that have large responses to pentobarbital (as expected) but also show appreciable responses to GABA (contrary to expectation). Furthermore, transfection of HEK 293 cells with alpha 1 plus gamma 2L subunits results in responses to GABA that are potentiated by the drug loreclezole, suggesting that a subunit resembling the beta 2 or beta 3 subunit had assembled with the alpha 1 gamma 2L subunits. In addition, some nontransfected HEK 293 cells respond to applications of GABA, and transfection of cells with alpha 1, beta 1, or gamma 2L subunits alone can result in the expression of GABA-elicited currents. In comparison, when QT6 quail fibroblasts are used as the expression system, no responses were seen in untransfected cells or in cells transfected with alpha 1, beta 1, or gamma 2L subunits alone or alpha 1 gamma 2L subunits. Furthermore, no response to GABA was seen in QT6 cells transfected with alpha 1 beta 2(Y205S) gamma 2L subunits, although cells gave strong responses to pentobarbital. These observations indicate that caution must be taken in interpreting the results of studies of the properties of GABAA receptors expressed in HEK 293 cells if the exogenous subunits result in the expression of low levels of functional GABAA receptors.

Amino Acid Sequence↗
PubMed1995

Source localization of middle latency auditory evoked magnetic fields.

The magnetic counterparts of middle latency auditory evoked responses (MLR) were measured for seven normal subjects with a 7-channel de superconducting quantum interference device (SQUID). The source of each component (Na, Pa, Nb and Pb) was estimated and plotted onto the individual magnetic resonance images (MRI). The source of Na, as well as those of Pa, Nb and Pb, was estimated to be in the supratemporal auditory cortex. The positions of Pa, Nb and Pb sources were compared with one another. No significant difference was observed between the positions of Pa and Nb sources. On the other hand, the source of Pb was found to be anterior to the sources of both Pa and Nb. It was suggested that there are more than two separate areas activated in the human auditory cortex during MLR.

Acoustic Stimulation↗
PubMed1995

Colocalization of ATP and nicotinic ACh receptors in the identified vagal preganglionic neurone of rat.

1. Effects of exogenous adenosine 5'-triphosphate (ATP) and acetylcholine (ACh) were investigated on acutely dissociated preganglionic neurones in the dorsal motor nucleus of vagus (DMV) of rats using whole-cell patch clamp recording methods. 2. The DMV neurones identified by retrograde transport of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) fixed onto the cervical vagal nerve bundle were large in size (25-35 microns diameter) and bipolar or tripolar in shape. 3. About 90% of DiI labelled DMV neurones responded to both ATP (10(-4) M) and ACh (10(-4) M) with inward currents at a holding potential (Vh) of -40 mV. 4. The ATP-induced current (IATP) and the ACh-induced current (IACh) reversed their polarities at membrane potentials between +5 and +15 mV, indicating that ATP and ACh increase the membrane permeability to cations. 5. The inhibitory potency of Reactive Blue on 5 x 10(-4) M IATP is more effective (concentration for half-inhibition (IC50), 4.4 x 10(-7) M) than suramin (IC50, 6.0 x 10(-6) M). In addition, alpha,beta-methylene ATP up to 10(-4) M could not induce any current. As intracellular application of guanosine 5'-O-(2-thiodiphosphate) (GDP beta S) did not block the IATP, the IATP was mediated not by guanosine triphosphate (GTP) binding protein, but rather by ligand-gated ionic channels, presumably via P2X receptors. 6. Currents produced by ACh were due to activation of nicotinic receptors because they were mimicked by nicotine and carbachol, and blocked by hexamethonium. In addition, muscarine evoked no response. 7. Only 25% of nucleus tractus solitarii (NTS) neurones and no hypoglossal neurones responded to the exogenous application of ATP. 8. These results suggest that vagal preganglionic neurones colocalize functionally nicotinic and P2X purinergic receptors.

Acetylcholine↗
PubMed1995

Exon skipping caused by a base substitution at a splice site in the GTP cyclohydrolase I gene in a Japanese family with hereditary progressive dystonia dopa responsive dystonia.

We report a novel mutation at a splice site in the GTP cyclohydrolase I gene in a Japanese family with hereditary progressive dystonia with marked diurnal fluctuation (HPD)/dopa responsive dystonia (DRD). Reverse transcriptase-initiated PCR (RT-PCR) of lymphocyte mRNA showed both normal and small size fragments in the HPD patient and his asymptomatic mother. Sequence analysis revealed that skip splicing of exon 1 to exon 3 occurred in the small fragment. The patient and his mother were heterozygous for G --> C substitution at conserved consensus sequence GT at 5' end of the intron 2. Quantitative RT-PCR showed that the expression of normal GTP cyclohydrolase I mRNA decreased in their lymphocytes, while the HPD patient had more expression of mutant GTP cyclohydrolase I mRNA than his asymptomatic mother.

Adult↗
PubMed1995

Methylmercury induces Ca(2+)-dependent hyperpolarization of mouse thymocytes: a flow cytometric study using fluorescent dyes.

The effect of methylmercury on mouse thymocytes was examined using fluorescent dyes for membrane potential and intracellular Ca2+. Methylmercury at concentrations of 1 microM or higher (up to 30 microM) produced hyperpolarization in a dose-dependent fashion. Charybdotoxin and quinine, but not 4-aminopyridine and tetraethylammonium, greatly suppressed methylmercury-induced hyperpolarization. Removal of external Ca2+ reduced the degree of hyperpolarization. Pretreatment of thymocytes with A23187 under Ca(2+)-free conditions abolished the hyperpolarization induced by methylmercury. Under both normal and Ca(2+)-free conditions methylmercury increased the intracellular concentration of Ca2+. The results suggest that the increase in intracellular Ca2+ is mediated through a Ca2+ release from intracellular stores as well as through influx of external Ca2+. Therefore, it is likely that methylmercury increases the intracellular concentration of Ca2+, resulting in activation of Ca(2+)-dependent K+ conductance of mouse thymocytes.

Animals↗
PubMed1995

Intraoperative risk factors associated with hepatic resection.

Risk factors associated with complications following hepatic resection were investigated retrospectively in 121 patients between January 1987 and April 1992. Fifty-seven patients recovered uneventfully, but 64 suffered post-operative complications and 15 died within 3 months. All those who died had suffered from hyperbilirubinaemia or bleeding and/or coagulopathy, which were considered critical complications after hepatic resection. Risk factors following hepatic resection were investigated statistically. Stepwise logistic regression analysis showed that serum levels of cholinesterase, the histology of the remaining liver and the volume of intraoperative blood loss were significantly associated with major complications (odds ratio 0.02, 5.14 and 4.97 respectively). Coexisting liver cirrhosis, deterioration of liver protein synthesis and massive intraoperative blood loss are important risk factors following hepatic resection.

Aged↗
PubMed1995

Formation of paramagnetic chromium in liver of mice treated with dichromate (VI).

The formation of paramagnetic chromium in the liver of male mice dosed with K2Cr2O7 (10, 20, and 40 mg Cr/kg) by a single ip injection was investigated by electron spin resonance (ESR) spectrometry. Both Cr(V) and Cr(III) complexes were detected in the mice livers at 15 min to 12 hr after Cr(VI) injection. The time course (15 min-12 hr) for the formation of paramagnetic Cr revealed that the hepatic levels of Cr(V) complexes decreased quickly during the first hour but decreased more slowly over the next 11 hr. However, in contrast to Cr(V), Cr(III) complexes appeared to persist for 12 hr after Cr(VI) treatment based on figures of Cr(III) signal. Thus, Cr(III) may be the ultimate form following reduction of Cr(VI) in liver. The total Cr content in liver of mice dosed with dichromate was also increased in a dose-dependent fashion (10-40 mg Cr/kg). However, Cr content in liver remained at similar levels for 15 min-6 hr, and slightly decreased at 12 hr after Cr(VI) injection. Under the same experimental conditions, hepatotoxicity, as estimated by the increase of serum ornithine carbamyl transferase activity, appeared at 3 hr after 20 and 40 mg Cr/kg of Cr(VI) injection, while 10 mg Cr/kg of Cr(VI) produced no hepatotoxicity even at 12 hr. Predosing with phenobarbital, which increased the hepatic levels of cytochrome P450, resulted in a decrease of the levels of Cr(V) and in a small increase of Cr content, without affecting Cr(VI) hepatotoxicity. On the other hand, pretreatment with buthionine sulfoximine, which depleted hepatic glutathione (GSH) levels, caused a decrease of Cr(VI) hepatotoxicity, but the levels of Cr(V) and Cr in the liver remained unchanged. These results demonstrated that in vivo formation of paramagnetic Cr, in particular Cr(V), in liver of mice is clearly detected and quantified by ESR spectrometry and that hepatic levels of cytochrome P450 and GSH are associated with the induction of biological effects by Cr(VI) in liver in vivo. The results also suggested that the formation of Cr(V) was not the only mechanism involved in the induction of hepatotoxicity by Cr(VI) compounds.

Animals↗
PubMed1995

The expression of Na+/K(+)-ATPase beta-subunit cRNA injected into Xenopus oocytes is affected by coinjection with alpha-subunit cRNA.

The cRNA for Torpedo californica Na+/K(+)-ATPase beta-subunit (cRNA beta) was injected into Xenopus oocytes alone or with the cRNA for the Na+/K(+)-ATPase alpha-subunit (cRNA alpha). When cRNA beta was injected alone, the amount of the beta-subunit that accumulated in oocytes increased with increasing amounts of injected cRNA beta. When cRNA beta and cRNA alpha were injected simultaneously, less beta-subunit accumulated than when cRNA beta was injected alone, whereas the Na+/K(+)-ATPase activity increased markedly. The decrease in the accumulation of the beta-subunit was dose-dependent upon the cRNA alpha. The mutant beta-subunit unable to assemble with the alpha-subunit accumulated in oocytes independently of cRNA alpha, suggesting that post-translational control mechanisms may serve to reduce the accumulation of the beta-subunit.

Animals↗
PubMed1995

Familial amyloid polyneuropathy associated with transthyretin Gly42 mutation: a quantitative light and electron microscopic study of the peripheral nervous system.

We performed extensive quantitative analyses of the peripheral nervous system (PNS) of two siblings with familial amyloid polyneuropathy (FAP) caused by a transthyretin (TTR) Gly42 mutation. Pronounced amyloid deposition was found in the sympathetic ganglia (SyG), dorsal root ganglia (DRG) and throughout the length of the peripheral nerve fibers with some accumulation in the more proximal portion. There was severe neuronal loss in the SyG and DRG together with nerve fiber depletion in the nerve trunk, while only a small amount of amyloid deposition with mild fiber loss was seen in the spinal roots. Sprouts of regenerating axons were very scanty even in the spinal nerves or roots. A teased fiber study mainly showed demyelinating fibers, but axonal degeneration was also present throughout peripheral nerves. An electron microscopic study showed fine amyloid fibrils in direct contact with the axoplasmic membrane of demyelinated axons and destruction of axons in some areas. Amyloid deposition within the PINS in this type of FAP resembled that in type I FAP (TTR Met30). However, direct axonal damage by amyloid fibrils appeared to be more prominent in our cases than in type I FAP. Lectin histochemistry using Ulex europaeus agglutinin I demonstrated preferential depletion of small neurons in the DRG and their primary afferent fibers in the spinal dorsal horn. Primary axonal degeneration and ganglionopathy due to amyloid deposition appear to be the pathogenetic mechanisms for peripheral neuropathy in this type of FAP.

Adult↗
PubMed1995

Effect of prior portosystemic shunt on early hepatic hemodynamics and sinusoids following 84% hepatectomy in dogs.

The effects of a prior portosystemic shunt (PSS) on the hepatic hemodynamics and sinusoids shortly after an 84% hepatectomy (Hx) were investigated in dogs. Fifteen mongrel dogs were divided into three groups, a 70% Hx group (n = 5), an 84% Hx group (n = 5) and an 84% Hx+PSS group (n = 5). In the last group, a shunt was inserted between the splenic and femoral veins prior to the hepatectomy. The systemic and hepatic hemodynamics were measured, before and 180 min after the hepatectomy, and the remaining liver tissue was then examined immunohistochemically by light microscopy using the thrombomodulin (TM) staining method. The postoperative portal vein pressure and the vascular resistance were significantly lower in the PSS group than in the 84% non-PSS group. The total postoperative hepatic blood flow was higher in the 84% non-PSS group than in the other two groups. Immunohistochemical observation after TM staining indicated that the sinusoidal endothelial cells in the 84% non-PSS group were markedly damaged 3 h after surgery. We conclude that a prior PSS improves the hepatic hemodynamics and is beneficial to the sinusoids within the first few hours of an 84% hepatectomy in dogs.

Animals↗
PubMed1995

Role of cytochrome P450 in hepatotoxicity induced by di- and tributyltin compounds in mice.

The role of cytochrome P450 in the induction of hepatotoxicity by butyltin compounds such as tributyltin chloride (TBTC) and dibutyltin dichloride (DBTC) was investigated in vivo. The pretreatment of mice with SKF-525A, which decreased hepatic levels of cytochrome P450, suppressed TBTC-induced hepatotoxicity, as estimated by serum ornithine carbamyl transferase activity, whereas pretreatment with phenobarbital (PB), which increased the levels of cytochrome P450, enhanced the hepatotoxicity of TBTC. In the case of DBTC, PB pretreatment enhanced hepatotoxicity, while SKF-525A had no effect. Under these experimental conditions only PB pretreatment was found to increase hepatic levels of tin in mice treated with TBTC. These results suggest that hepatic metabolism of butyltin compounds by cytochrome P450 is more closely related to the induction of hepatotoxicity by TBTC than by DBTC. The active tin compounds formed during hepatic metabolism, which are responsible for induction of hepatotoxicity, will be discussed.

Animals↗
PubMed1995

Three-dimensional display of the pelvic structure of anorectal malformations based on CT and MR images.

Three-dimensional images of the pelvic structure of patients with anorectal malformation (ARM) were constructed by computer graphics based on radiographic computerized tomography (CT) and magnetic resonance (MR) images. Organ contour data from CT images and raw MR image data were transferred to a personal computer and to a graphic workstation respectively. On MR image processing, organs were extracted semiautomatically by thresholding enclosed areas. After several steps of image processing, three-dimensional anatomy of each anomaly was visualized with emphasis on position and shape of the muscle complex. In control patients without an anomaly, images showed that the rectum is supported by the levator muscle from behind and descends along with the urethra. In the male patient, the anal canal separates from the urethra and penetrates through the middle of the sphincter complex to reach the orifice. In those with low-type anomaly with a fistula opening to the perineum or the vestibule, images showed the fistula descending through the anterior portion of the sphincter complex. Images of those with a rectourethral fistula could show the muscle complex behind the rectum and at the region where the external sphincter should be. In those with cloacal anomalies, anatomical position and the shape of three different viscera were easily recognized, and the muscle complex was shown like that of rectourethral-type anomalies. This study is a new approach to the anomaly to facilitate understanding it and can assist a surgeon in planning a procedure. This kind of application would make it possible for a surgeon to consider the strategy on a display screen before the real surgery.

Anal Canal↗