Search PubMed⌕ Search

Biomedical subjects

T Kondo

Publications and source records attributed to T Kondo.

At least 775 records · Page 43Linked to original sources
PubMed1995

Weakened cellular scavenging activity against oxidative stress in diabetes mellitus: regulation of glutathione synthesis and efflux.

Glutathione functions to scavenge oxidants or xenobiotics by covalently binding them and transporting the resulting metabolites through an adenosine 5'-triphosphate-dependent transport system. It has been reported that the intracellular concentration of glutathione decreases in diabetes mellitus. In order to elucidate the physiological significance and the regulation of anti-oxidants in diabetic patients, changes in the activity of the glutathione-synthesizing enzyme, gamma-glutamylcysteine synthetase, and transport of thiol [S-(2,4-dinitrophenyl)glutathione] were studied in erythrocytes from patients with non-insulin-dependent diabetes and K562 cells cultured with 27 mmol/l glucose for 7 days. The activity of gamma-glutamylcysteine synthetase, the concentration of glutathione, and the thiol transport were 77%, 77% and 69%, respectively in erythrocytes from diabetic patients compared to normal control subjects. Treatment of patients with an antidiabetic agent for 6 months resulted in the restoration of gamma-glutamylcysteine synthetase activity, the concentration of glutathione, and the thiol transport. A similar impairment of glutathione metabolism was observed in K562 cells with high glucose levels. The cytotoxicity by a xenobiotic (1-chloro-2,4-dinitrobenzene) was higher in K562 cells with high glucose than in control subjects (50% of inhibitory concentration 300 +/- 24 mumol/l vs 840 +/- 29 mumol/l, p < 0.01). Expression of gamma-glutamylcysteine synthetase protein was augmented in K562 cells with high glucose, while enzymatic activity and expression of mRNA were lower than those in the control subjects. These results suggest that inactivation of glutathione synthesis and thiol transport in diabetic patients increases the sensitivity of the cells to oxidative stresses, and these changes may lead to the development of some complications in diabetes mellitus.

Aged↗
PubMed1995

Flow threshold for enhanced phorbol ester binding in the ischemic gerbil brain.

The correlation between regional phorbol ester binding and cerebral blood flow (CBF) was evaluated in the gerbil brain after 2-hour unilateral common carotid artery occlusion. [3H]phorbol 12,13-dibutyrate (PDBu) was used as a specific ligand for estimating the translocation of protein kinase C (PKC), and CBF was determined by the [14C]iodoantipyrine method. A quantitative autoradiographic method permitted concurrent measurement of these two parameters in the same brain. In the ischemia group of the animals, statistically significant, inverse correlations were noted between the CBF and PDBu binding in the hippocampus (CA1 and CA3 regions and dentate gyrus), the caudate-putamen and lateral nuclei of the thalamus. In these regions, the PDBu binding increased progressively as CBF fell below 35-40 ml/100 g/min. On the other hand, the PDBu binding in the cerebral cortices did not show any significant changes even when CBF was decreased to below 35 ml/100 g/min. The above data suggest that (1) the translocation of PKC to the cell membrane may be regionally specific in response to ischemia, and may remain in the regions particularly vulnerable to ischemia such as the hippocampus, caudate-putamen and lateral nuclei of the thalamus in the early ischemic phase; (2) the threshold of CBF below which PKC begins to translocate to the cell membrane in the above regions, may be 35-40 ml/100 g/min in 2-hour ischemia.

Animals↗
PubMed1995

Detection of equine arteritis virus (EAV) by polymerase chain reaction (PCR) and differentiation of EAV strains by restriction enzyme analysis of PCR products.

A polymerase chain reaction (PCR) based assay capable of detecting and differentiating seven strains of equine arteritis virus (EAV) from around the world was developed. The primers for the PCR were chosen from the ORF6 gene encoding the unglycosylated membrane protein (M). Viral RNA from cell culture fluids infected with each of the seven EAV strains and RNA from the live vaccine, Arvac, was detected by PCR using four sets of primers. The sensitivity of detection was increased from 100 to 1,000 times by performing nested PCR enabling the detection of RNA at a level of 0.5-5 PFU. Differentiation among the virus strains and the live vaccine was achieved by cutting the PCR-amplified products from three sets of primers with six restriction endonucleases. Using this procedure it was possible to distinguish among the seven EAV strains used.

Base Sequence↗
PubMed1995

Ultrastructure and immuno-cytochemistry of BHK-21 cells infected with a modified Bucyrus strain of equine arteritis virus.

Morphogenesis of a modified Bucyrus strain of equine arteritis virus (EAV) in BHK-21 cells was studied. Bacillary tubules were first detected in the cytoplasm 8 h after infection, and mature virions 79 to 122 nm in diameter, 101 nm on average, were mostly observed in the cisternae of the rough endoplasmic reticulum (RER) at 12 h or later. They had isometrical cores and morphological subunits in the outer layer. Budding occurred from the RER and the outer nuclear membrane, but not from the cell surface. Structural linkage was detected between the tubule and the virus core. Aberrant strands were occasionally demonstrated within the nucleus 12 h after infection, and immunofluorescence and immunogold labeling revealed viral antigen also in the nucleus.

Animals↗
PubMed1995

Brain beta 2-microglobulin levels are elevated in the striatum in Parkinson's disease.

beta 2-Microglobulin (B2-MG) content was measured for the first time in the brain (caudate nucleus, putamen, and cerebral cortex) from control and parkinsonian patients by a highly sensitive sandwich enzyme immunoassay. The concentrations of B2-MG in dopaminergic striatal regions were significantly higher in parkinsonian patients than those in controls, whereas those in the cerebral cortex showed no significant difference between parkinsonian and control subjects. Tumor necrosis factor-alpha (TNF-alpha) concentrations were also increased in the striatum, confirming our previous findings, but not in the cerebral cortex. Since TNF-alpha may induce B2-MG expression, these results suggest that an immunological response may occur in the nigrostriatal dopaminergic regions in Parkinson's disease.

Aged↗
PubMed1995

Effect of gastrin-releasing peptide (GRP) on guinea pig gallbladder contraction in vitro.

Few studies have reported the effects of gastrin-releasing peptide (GRP)/bombesin on the guinea pig gallbladder, and the results are contradictory. Because such contradictory results may, in part, be due to technical factors, we investigated the effect of GRP on guinea pig gallbladder smooth muscle, using an improved horizontal organ bath. The guinea pigs were killed and the gallbladder was removed. Four longitudinal muscle strips (2 x 12 mm) were suspended in Krebs-Ringer solution at 37 degrees C and aerated with 95% O2 and 5% CO2. The mechanical activity of the strips was recorded isotonically by displacement-voltage transducers, via L-arms, to which a piezoelectric element with a frequency of 100 Hz and movement of 50 microns was applied. GRP contracted gallbladder muscle strips dose dependently, but the calculated maximal response was 22.4% and 20.1% of the acetylcholine- and cholecystokinin octapeptide (CCK8)-induced responses, respectively. The GRP-induced contraction was unaffected by the muscarinic blocker, atropine, or by the CCK receptor antagonist, loxiglumide. It is concluded that GRP weakly, but apparently directly, stimulates guinea pig gallbladder contraction.

Acetylcholine↗
PubMed1995

An immunohistochemical and monastral blue-vascular labelling study on the involvement of capsaicin-sensitive sensory innervation of the junctional epithelium in neurogenic plasma extravasation in the rat gingiva.

Nerve fibres immunoreactive for substance P (SP) and calcitonin gene-related peptide (CGRP) were located preferentially at the base of the junctional epithelium. Occasional fibres were observed in close proximity to the subepithelial, small blood vessels. The vascular connective tissue papillae projecting into the epithelium were more densely surrounded by SP- and CGRP-immunoreactive fibres in the interdental col than in other regions of the gingiva. In some cases, hyperplasia of the junctional epithelium was noted in the interdental col where the connective tissue papillae were invaded by widened vessels, indicating severe irritation. SP- and CGRP-immunoreactive fibres around these papillae showed increases in their immunoreactivity and thickness, with some fibres terminating as large expansions. Double immunohistochemical staining revealed the co-existence of SP and CGRP in all nerve fibres within and under the junctional epithelium. Capsaicin pretreatment eliminated most of the immunoreactivity for both peptides. Intravenous infusion of capsaicin or SP caused increased permeability in vessels underlying the junctional epithelium, as indicated by Monastral blue labelling. Labelled vessels were arranged not only in a network extending under the epithelium but also in loops protruding into the connective tissue papillae. These labelled vessels were most abundant in the interdental col, where vascular loops with more complex configurations exhibited strong staining in their walls. In the case of hyperplasia of the junctional epithelium in the interdental col, widened vessels showing extensive labelling in their walls were observed. In capsaicin-pretreated animals, capsaicin-induced extravasation was abolished, while the effect of SP was still observed. These findings provide evidence that capsaicin-sensitive sensory nerves supplying the junctional epithelium are involved in neurogenic plasma extravasation in the rat gingiva. The enhancement of neurogenic plasma extravasation in the col may be vascular response associated with a higher susceptibility of this region to gingival inflammation.

Animals↗
PubMed1995

Difference in surface properties between Escherichia coli and Staphylococcus aureus as revealed by electrophoretic mobility measurements.

Electrophoretic mobilities of Escherichia coli and Staphylococcus aureus were measured in media of different pH values and ionic strengths at 310 K and the results were analyzed via a new mobility formula which was derived on the assumptions of uniform charge distribution in the cell surface layer of finite thickness and ion-penetrability in the layer. E. coli was shown to have a more negatively charged and less soft surface than that of S. aureus. It is suggested that electrophoretic mobility measurements can be used to detect the difference in surface structure between gram-positive and gram-negative bacteria.

Cell Membrane↗
PubMed1995

Effects of zonisamide on dopaminergic system.

Effects of zonisamide (ZNS) on extracellular dopamine (DA), its precursor 3,4-dihydroxyphenylalanine (DOPA), its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) levels in the striatum as well as hippocampus of freely moving rats were studied. Intracellular DA, DOPA, DOPAC and HVA levels, as well as DOPA accumulation as an index of tyrosine hydroxylase activity in the rat brain in vivo, DA re-uptake in the striatum and hippocampus, and monoamine oxidase (MAO) activities were also determined. Acute administrations of therapeutic ZNS doses (20 and 50 mg/kg) increased striatal extracellular DOPA levels, intracellular striatal and hippocampal DOPA levels, and stimulated DOPA accumulation in both brain regions. ZNS also increased striatal and hippocampal intracellular as well as extracellular DA and HVA levels, but decreased those of DOPAC levels. Chronic (3 weeks) administrations of therapeutic ZNS doses (20 and 50 mg/kg/day) increased intracellular DA, DOPA, DOPAC and HVA levels in striatum and hippocampus. ZNS-induced changes were greater in intracellular levels than in extracellular levels. Acute and chronic supratherapeutic ZNS dose (100 mg/kg) administration decreased intracellular levels of all substances detectable in both brain regions, and inhibited DOPA accumulation. Both subtypes of MAO (type A and type B) activities were weakly inhibited by ZNS. ZNS showed no effect on DA re-uptake in striatum nor in hippocampus. These results suggest that therapeutic ZNS doses increase DOPA accumulation as well as both intracellular and extracellular DA, DOPA and HVA levels. However, such doses also decrease extracellular and intracellular DOPAC levels by enhancing DA synthesis and/or by selectively inhibiting MAO-B activities. In addition, chronic therapeutic ZNS dose administration enhances DA synthesis, which results in increased intracellular DA, its precursor and its metabolites levels. On the other hand, both acute and chronic supratherapeutic ZNS dose administrations inhibit DA turnover. These ZNS effects on DA metabolism are at least partly involved in the mechanisms of action of ZNS.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1995

Screening and determination of methamphetamine and amphetamine in the blood, urine and stomach contents in emergency medical care and autopsy cases.

Methamphetamine (MA) and amphetamine (AMP) were screened and their levels were determined using the Toxi-Lab thin-layer chromatography system and gas chromatography-mass spectrometry, respectively, in the blood, urine and stomach contents from 211 emergency medical care and 417 autopsy cases. MA and AMP were detected in 5 emergency medical cases, and the blood MA and AMP concentrations ranged from 0.697-0.041 micromol/100 g and from 0.0944-0.0003 micromol/100 g, respectively. MA and AMP were detected in 19 autopsy cases, in which blood MA and AMP concentration ranged from 14.3-0.123 micromol/100 g and from 0.256-0.0017 micromol/100 g, respectively. The autopsy cases included 5 cases of sudden death with blood MA concentration of less than 3 micromol/100 g. MA and AMP screening and determination in emergency medical care and autopsy cases provide useful information and are indispenable in clarifying the dimensions of MA abuse in Japan.

Journal Article↗
PubMed1995

Screening of volatile substances and determination of toluene (a thinner component) in the blood and urine in emergency medical care and autopsy cases by the pulse heating method.

Screening of volatile substances was performed by pulse heating gas chromatography - mass spectrometry (GC-MS) using a GS-Q column in 211 emergency medical care and 342 autopsy cases. At least 36 standard substances could be separately detected. Six kinds of volatile substances were screened in a total of 553 cases. Toluene and/or hippuric acid were detected in the blood and/or urine in respectively, 4 emergency medical care and 8 autopsy cases. There were 11 abusers (9 males and 2 females) in these 12 positive cases. The ages of the abusers ranged from 13-26 years. There was no particular pattern to the monthly frequency distribution of identification of thinner (toluene) abuse cases, which occurred throughout the year. It is believed that these data at least partly reflect the present status of thinner/glue abuse in Japan. We conclude that pulse heating GC-MS is useful in the screening and quantitative determination of volatile substances including toluene and other thinner/glue components.

Journal Article↗
PubMed1995

The role of an operating microscope in medico-legal practice.

This article describes our experience in the use of a binocular surgical microscope at autopsy for the in situ forensic examination of various types of mechanical skin wounds. The microscopic image was visualised on a closed-circuit television monitor, and colour photographs and video recordings were simultaneously obtained from the monitor. With abrasions, small epidermal tags, which play a key role in the determination of external force direction, were clearly observed. With lacerations, crushing of the epidermis was observed at the wound margin, and continuous bridges of connective tissue and/or blood vessels were also found within the wound cavity. With incised wounds, the epidermis was intact up to the wound margin, and there was no continuous bridge within the wound cavity. Using these differences, it was, therefore, simple to distinguish lacerations from incised wounds. Ligature marks due to hanging were clearly observed, with petechial haemorrhages and minute abrasions readily seen in the lesion. For stab wounds caused by a single-edge knife, the morphological difference between the two ends of the wound caused by the sharp blade and the blunt side could be distinguished. It was also possible to confirm the identification of unknown cadavers by observing old wound scars using the operating microscope. Abnormal lesions of the blood vessels, such as a mechanical tear of the vertebral artery (the origin of a subarachnoid haemorrhage) and the atherosclerotic stenosis of the coronary artery, were detectable. In addition, the microscope was useful as a teaching aid to colleagues and medical students to study the nature of the wounds during or after the autopsy. We believe that this system presents advantages in terms of education and training of forensic pathologists and physicians as well as crime investigation officers.

Journal Article↗
PubMed1995

Diagnostic usefulness of activation-recovery interval for reciprocal ECG changes. Effects of regional myocardial cooling, warming, or coronary occlusion on epicardial electrograms in dogs.

The proximal left circumflex coronary artery (LCx) was cannulated and perfused with blood from the carotid artery in nine open-chest dogs. Perfused blood temperature was modulated by immersing a bypass tube in a temperature-controlled water tank. Two epicardial electrodes were placed, one at the LCx area and one at the left anterior descending coronary artery (LAD) area. The temperature of the autoperfused blood was set at 23 degrees C and was gradually elevated to 42 degrees C during 30 minutes. The QRS, ST-T, and QRST areas, and the activation-recovery interval of the electrode at the LCx area, changed unidirectionally in relation to elevation of the blood temperature. Although the QRS, ST-T, and QRST areas of the electrode at the LAD area changed in proportion to changes in the electrode at the LCx area, the activation-recovery interval of the electrode at the LAD area remained constant in all dogs. During 2-minute occlusion of the proximal LCx (n = 7), the activation-recovery interval of the electrode at the LAD area also remained constant despite the presence of reciprocal electrocardiographic changes. The activation-recovery interval is a useful index for defining whether a change in ST-T in a unipolar electrogram is due to a local electrophysiologic effect or a reciprocal effect.

Action Potentials↗
PubMed1995

Internal potassium shift in premature infants: cause of nonoliguric hyperkalemia.

To study the pathophysiology of nonoliguric hyperkalemia, we measured serum potassium concentration and external K balance (intake and excretion), and estimated internal K balance (a shift from intracellular space to extracellular space) in 24 nonoliguric premature infants during the first 72 hours after birth. Data were analyzed from two aspects: gestational age (group 1, 24 to 28 weeks, n = 9; group 2, 29 to 32 weeks, n = 9; group 3, 33 to 36 weeks, n = 6) and postnatal age (0 to 72 hours). Serum K concentration rose from baseline (0 hour) to 24 hours in groups 1 and 2 (p < 0.01) but did not rise in group 3. The external K balance was negative in all groups during the study period, and was more negative in the more premature infants (group 1 > group 2 > group 3) during the second 24 hours. There was a significant difference (p < 0.01) between the internal K balance of the three groups during the first 24 hours (group 1 > group 2 > group 3), and the K shift decreased significantly (p < 0.05) during the study period in groups 1 and 2. The more premature the infants, the larger the K shift and the larger the rise in serum K concentration during the first 24 hours, and the more negative the external K balance after 24 hours. These data indicate that K loading caused by the K shift associated with prematurity produces a rapid rise in serum K concentration, resulting in an increase in urinary K excretion. We conclude that an internal K shift inversely proportional to gestational and postnatal age is the primary cause of nonoliguric hyperkalemia in very premature infants.

Extracellular Space↗
PubMed1995

Effect of cataract surgery on aqueous turnover and blood-aqueous barrier.

We evaluated changes in aqueous outflow and blood-aqueous barrier (BAB) disruption after cataract surgery in two randomly selected groups of eyes. In one group, a high-viscosity viscoelastic was used for intraocular lens (IOL) implantation; in the other, a low-viscosity viscoelastic. Fluorophotometry was used to evaluate aqueous humor dynamics five to seven hours after IOL implantation. Aqueous outflow after IOL implantation in operated eyes was nearly twice that in the fellow eyes, which served as controls. Mean protein concentration in the anterior chamber was also elevated in operated eyes. However, postoperative aqueous outflow did not differ significantly between the two groups. The substantial increase in aqueous outflow observed postoperatively and the increase in aqueous humor protein concentration were closely related to BAB disruption. These results suggest that BAB disruption may be a main cause of the transient high intraocular pressure observed after IOL implantation in both groups.

Aged↗
PubMed1995

Targeted mutation in the Fas gene causes hyperplasia in peripheral lymphoid organs and liver.

Fas, a type I membrane protein that transduces an apoptotic signal, is expressed in lymphocytes as well as in various tissues such as the liver, lung and heart. The mouse lymphoproliferation (lpr) mutation is a leaky mutation in Fas. By means of gene targeting, we generated a mouse strain which is completely deficient in Fas. In addition to the massive production of lymphocytes, the Fas-null mice showed substantial liver hyperplasia, which was accompanied by the enlargement of nuclei in hepatocytes. The Fas system seems to play a role in the apoptotic process to maintain homeostasis of the liver as well as the peripheral lymphoid organs.

Animals↗