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Biomedical subjects

T Kondo

Publications and source records attributed to T Kondo.

At least 1,027 records · Page 57Linked to original sources
PubMed1992

Hydrolysis of phospholipid monolayers by phospholipase D at the oil/water interface under the control of the potential drop across the monolayer.

A new method has been proposed for measuring the enzymatic hydrolysis of phosphatidylcholine (PC) monolayers formed at the polarized nitrobenzene(NB)/water(W) interface under the precise control of the potential drop across the interface. As a probe for the hydrolysis, the method utilized the capacitance (Cd1) of the monolayer. Phospholipase D (EC. 3.1.44., PLD) converted L-alpha-dipalmitoylphosphatidylcholine (DPPC) in the monolayer to L-alpha-dipalmitoylphosphatidic acid (DPPA), leading to a drastic decrease in Cdl. This change in Cdl was sensitive enough to monitor the course of enzymatic hydrolysis of the PC monolayer by PLD. The rate of the hydrolysis was markedly dependent on the potential drop across the interface. When the potential of the aqueous phase with respect to that of the NB phase (delta W0 phi) was -140 mV, no hydrolysis was observed, whereas at delta W0 phi = 60 mV the hydrolysis proceeded promptly.

Electrochemistry↗
PubMed1992

Mouse rRNA gene transcription factor mUBF requires both HMG-box1 and an acidic tail for nucleolar accumulation: molecular analysis of the nucleolar targeting mechanism.

RNA polymerase I requires at least two nucleolar transcription factors, UBF and SL-1, for ribosomal RNA gene (rDNA) transcription. UBF requires SL-1 for the formation of a stable initiation complex on the rDNA promoter region. We have determined the region of mouse UBF (mUBF) required for nucleolar targeting. Although mUBF has a nuclear localization sequence, this sequence alone is not sufficient for mUBF to accumulate in the nucleolus. Deletion analyses show that mUBF requires a wide region except for the N-terminal 101 amino acids for nucleolar targeting. Deletion of either the HMG-box1, a region crucial for rDNA binding, or the acidic tail, a region that may interact with SL-1, results in the loss of nucleolar targeting. We show by DNA affinity analysis that the HMG-box1 is absolutely necessary for mUBF to bind to the upstream control element of the rDNA. We also show that mUBFs with various internal deletions retain both nucleolar targeting and DNA binding ability. A clear correlation was demonstrated between the DNA binding and nucleolar targeting ability. These results suggest that UBF is transferred to the nucleus by its NLS and is sequestered in the nucleolus by its specific and stable binding to the rDNA promoter via HMG-boxes and the acidic tail.

Animals↗
PubMed1992

Enhanced rectal absorption and reduced local irritation of the anti-inflammatory drug ethyl 4-biphenylylacetate in rats by complexation with water-soluble beta-cyclodextrin derivatives and formulation as oleaginous suppository.

To improve the rectal delivery of ethyl 4-biphenylylacetate (EBA), a prodrug of the anti-inflammatory drug 4-biphenylylacetic acid (BPAA), the use of highly water-soluble 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) and heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CyD) was investigated and compared with the use of the parent beta-cyclodextrin (beta-CyD). Among the three beta-CyDs, HP-beta-CyD was best at improving the rectal bioavailability of EBA in rats after single and multiple administrations of oleaginous suppositories (Witepsol H-5) containing the complexes. To gain insight into the enhancing effect of beta-CyDs, the absorption behaviors of EBA (observed by monitoring BPAA as an active metabolite of EBA) and beta-CyDs themselves were examined in vitro, in situ, and in vivo. The in situ recirculation study revealed that the complexed form of EBA was less absorbable from the rectal lumen in the solution state, but this disadvantageous effect of beta-CyDs was compensated in part by the inhibition of the bioconversion of EBA to BPAA. When beta-CyDs were coadministered with EBA in vivo, however, rather high amounts of HP-beta-CyD (approximately 26% of dose) and DM-beta-CyD (approximately 21% of dose), compared with beta-CyD (approximately 5% of dose), were absorbed from the rat rectum. Thus, the enhancement of rectal absorption of EBA in vivo can be explained by the facts that the hydrophilic beta-CyDs increased the release rate of EBA from the vehicle and stabilized EBA in the rectal lumen and that the drug was partly absorbed in the form of the complex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Application of superfine fiberscope for endovasculoscopy, ventriculoscopy, and myeloscopy.

In the past three years, we have used a superfine fiberscope for endovasculoscopy, ventriculoscopy, and myeloscopy. Flexible superfine fiberscope, 0.75 mm in outer diameter, could visualize various intravascular findings. In in-vivo canine experiment, sequential changes of thrombus produced by endothelial abrasion by needle or balloon in the canine carotid artery can be clearly seen. And thrombolysis by focal arterial injection of tissue plasminogen activator was sequentially observed. In the clinical study, we could evaluate the stenotic lesions of the subclavian and vertebral arteries before and after balloon angioplasty. During ventriculoscopy, a 2 mm of mini-caliber fiberscope was introduced under ultrasound monitoring, and provided clear visualization of intraventricular tumours. In myeloscopy, draining veins of arteriovenous malformations and nerve roots of the cauda equina could be clearly seen by flexible fiberscope. From these results, it can be said that the superfine fiberscope provides clear and useful visualizations of the interior of vessels, ventricles, and the intrathecal area of the spinal canal. The new applications of this superfine fiberscope for minimally invasive neurosurgery may bring about a marked improvement of therapeutic results.

Animals↗
PubMed1992

A possible association between basic amino acids of position 13 of DRB1 chains and autoimmune hepatitis.

Fifty-one patients with autoimmune hepatitis have been studied for HLA association by conventional serology and also by modified polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) genotyping. HLA-DR4 was significantly associated with autoimmune hepatitis (46 of 51 patients, 90.2%). DNA typing of the DRB1 gene for 43 DR4-positive patients by using the PCR-RFLP technique revealed that of 43 patients, 33 had DRB1*0405 (Dw15), five had DRB1*0406 (DwKT2), four had DRB1*0403 (Dw13a), two had DRB1*0401 (Dw4), two of 43 had DRB1*0407 (Dw13b) and one had DRB1*0408 (Dw14b). Thus, there was no significant difference in Dw frequencies between DR4-positive patients and DR4-positive healthy subjects. These findings suggest that the DR4-specific sequence (Val 11 and His 13 at amino acid positions 11 and 13, respectively), but not particular Dw-associated DR4 sequence, in the first domain of the DRB1 chain contributes to susceptibility to autoimmune hepatitis among Japanese. Interestingly, all five of the DR4-negative patients had the DR2 specificity (DRB1*1502 or 1601). Taken together, these results imply that the basic amino acids at position 13, which is present only on the DR2 and DR4 B1 molecules (Arg on DR2 and His on DR4), are most important for determining the predisposition to autoimmune hepatitis.

Amino Acid Sequence↗
PubMed1992

Mitochondrial complex I and II activities of lymphocytes and platelets in Parkinson's disease.

Mitochondrial Complex I deficiencies have been described not only in the brain but also in the skeletal muscle and platelets in Parkinson's disease (PD). We report activities of Complex I, II, III, and IV in lymphocytes and platelets in 20 patients with PD and age-matched controls. A small but a significant decrease in the platelet Complex I activity was found in PD (9.14 +/- 1.86 units/mg protein) compared with that in the control (12.37 +/- 2.66 units/mg protein) (P = 0.0002). The lymphocyte Complex I activity was about the same between PD and the control. The activity of Complex II was slightly diminished in both platelets and lymphocytes in PD. Rather small decrease in the platelet Complex I activity in PD may be clinically non-significant. But it may indicate the presence of a qualitatively similar abnormality in platelets as in the nigro-striatal neurons. The cause for decrease in the Complex II activity is unknown at this moment. Further studies seem necessary.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1992

Peritoneal absorption of pancreatic enzymes in dogs.

To elucidate peritoneal absorption of pancreatic enzymes, plasma levels of amylase, lipase, and trypsinogen were measured after the intraperitoneal injection of 10 ml human pancreatic juice in dogs. Plasma pancreatic amylase, lipase, and trypsinogen were determined using the immunoassay specific to the corresponding human pancreatic enzyme to exclude cross-reaction with the endogenous enzyme activities of the canine plasma. Plasma immunoreactivity of human amylase persistently rose during 24 h after the injection, whereas elevation of plasma amylase enzyme activity become significant only at 24 h. Increase of plasma lipase was not remarkable. Significant increase of the immunoreactivity was observed only at 24 h but there was no significant increase of the enzyme activity during this period. Plasma trypsinogen immunoreactivity peaked at 2 h remained significantly elevated during 24 h. The transperitoneal absorption of pancreatic enzymes in dogs was confirmed using intraperitoneal injection of human pancreatic juice combined with immunoassay specific to human pancreatic enzymes.

Amylases↗
PubMed1992

Molecular form of pancreatic elastase 1 in human plasma.

In order to study the molecular forms of immunoreactive pancreatic elastase 1 (IRE) in human plasma, we investigated the characteristics of proelastase 1, elastase 1, and their alpha 1-protease inhibitor (alpha 1-PI) complexes on anion-exchange (Mono Q) chromatography, gel (Superose 12) chromatography, and enzyme immunoassay systems with monoclonal antielastase 1 antibodies of different affinities for alpha 1-PI-elastase 1 and alpha 1-PI-proelastase 1 complexes. The rate of complex formation between proelastase 1 and alpha 1-PI was dependent on temperature of incubation and concentration of alpha 1-PI. At 37 degrees C, 90% of proelastase 1 was bound to alpha 1-PI during 2 h of incubation of purified human proelastase 1 with human alpha 1-PI. Similar results were also obtained by 2 h of incubation of proelastase 1 with human plasma at 37 degrees C. Therefore, under physiological conditions, neither free proelastase 1 nor elastase 1 can be detected in the human blood stream, and most IRE exists as the complex of proelastase 1 with alpha 1-PI in human plasma.

Chromatography, Ion Exchange↗
PubMed1992

Differences in the transport systems between cementocytes and osteocytes in rats using microperoxidase as a tracer.

Microperoxidase (MP) tracer was injected intravenously into rats to investigate any differences in transport pathways of tissue fluids in the lacunae and canaliculi of cementum and bone. Light microscopically, in deep cementum lacunae, pericellular spaces contained a large amount of MP, while close to the cementum surface, the spaces contained scarcely any. In bone, MP was detected throughout all pericellular spaces. MP was detected intracellularly as granular reaction products in most cementocytes and osteocytes. Electron microscopically, MP was found in the pericellular spaces of cementum and bone lacunae, particularly on collagen fibrils and amorphous material. MP deposits were also intense along the plasma membrane of cementocytes in the deep cementum and along the innermost edge of the deep cementum matrix and bone matrix. In uptake of MP by cementocytes, although extracellular tracer was deposited extensively along the plasma membrane of the deeply positioned cementocytes, uptake by these deep cementocytes was less than that of those close to the surface. However, in bone, most osteocytes showed uniform uptake. These results suggest that the transport pathways for tissue fluids in cementum are in the pericellular spaces, but that cementum has an uneven circulation of tissue fluid. In cementum, although there seems to be a well-developed canalicular system to transport tissue fluid into the deep regions, the deep cementocytes had less endocytotic ability than those close to the surface.

Animals↗
PubMed1992

Immunohistochemical study of nerve fibres with substance P- or calcitonin gene-related peptide-like immunoreactivity in the junctional epithelium of developing rats.

The beginning of innervation in the junctional epithelium of maxillary first molars was examined in gingival tissues from 19 to 32-day-old rats. Substance P- or calcitonin gene-related peptide (CGRP)-like immunoreactivity was demonstrated by the avidin-biotin peroxidase complex method. In 19-day-old rats, nerve fibres with substance P- or CGRP-like immunoreactivity were seen in the connective tissue and oral epithelium, but not in the reduced enamel epithelium, which would be transformed into the junctional epithelium. In 21-day-old rats, the fibres with substance P- or CGRP-like immunoreactivity formed a plexus in the oral sulcular epithelium and thin varicose fibres were seen for the first time entering the adjacent reduced enamel epithelium. These fibres also penetrated the middle portion of the reduced enamel epithelium, but did not reach the cuboidal reduced ameloblasts. More nerve fibres had CGRP-like immunoreactivity than substance P-like immunoreactivity. In 23-day-old rats, many fibres with both immunoreactivities were seen in the basal layers of the junctional epithelium, but only a few were seen in its superficial layers. In 28-32-day-old rats, numerous fibres with both immunoreactivities were distributed in the whole junctional epithelium and showed a similar pattern of innervation. For all immunoreactive fibres, the density in the middle portion in the junctional epithelium was the highest. The nerve plexus was formed in the basal layers and some fibres with a varicose appearance were found in the superficial layers.

Animals↗
PubMed1992

HLA class II molecules and autoimmune hepatitis susceptibility in Japanese patients.

To investigate the association between autoimmune hepatitis and HLA alleles in Japanese patients, serological typing and class II genotyping were performed using the polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) method. Serological typing showed that HLA-B54, -DR4, -DR53, and -DQ4 were significantly more frequent in patients with autoimmune hepatitis than in controls. HLA-DR4 was most frequently associated with autoimmune hepatitis (88.7%). In PCR-RFLP typing, the frequency of DRB1*0405 was significantly higher in autoimmune hepatitis than in controls. However, there was no significant difference in the frequency of Dw between the patients and the controls who were DR4-positive. The significant increase observed in DQA1*0301 and DQB1*0401 was explained by a linkage disequilibrium with DR4. Six DR4-negative patients had DR2, but there was no significant difference in the frequency of the DR2-associated Dw-alleles compared with the DR2-positive controls. No DPB1 allele was significantly associated with autoimmune hepatitis. These findings suggest that the basic amino acid at position 13, which is present only on the DR2 and DR4 B1 molecules (Arg on DR2 and His on DR4), contributes to the susceptibility to autoimmune hepatitis among the Japanese.

Adult↗
PubMed1992

Pancreatic stone predominantly composed of fatty acid calcium.

A 41-year-old man with chronic pancreatitis and pancreatic stones predominantly composed of fatty acid calcium is reported. He had complained of occasional abdominal pain for 10 years and visited the hospital because of a severe attack of abdominal pain. Laboratory data supported a diagnosis of pancreatitis. Computed tomography (CT) showed a high-density area in the head of the pancreas, and the CT number of this high-density area was lower than usual for pancreatic stones. Ultrasonography and endoscopic retrograde pancreatography showed a cystic lesion with small pancreatic stones in the head of the pancreas and irregular dilatation of the main pancreatic duct. Pancreaticojejunostomy and resection of pancreatic cyst were carried out for repeated episodes of abdominal pain under the diagnosis of chronic pancreatitis. The pancreatic stones obtained at surgery were proved to be mainly composed of fatty acid calcium after analysis of chemical composition of the stones. Fatty acid calcium was sometimes found in the biliary stones but never in the pancreatic stones.

Adult↗
PubMed1992

Juvenile parkinsonism: ventricular CSF biopterin levels and clinical features.

Total biopterin (T-BP) levels in the ventricular cerebrospinal fluid (CSF) and clinical features of 19 patients with juvenile parkinsonism (JP: Parkinson's disease manifesting below the age of 40) were evaluated and compared with 61 patients with classical Parkinson's disease (classical PD: symptoms developing at the age of 40 or above). The JP patients were divided into two subgroups: JP-I; those with good response to levodopa followed by marked motor fluctuations and dopa-induced dyskinesias (DID), JP-II; those with milder response than JP-I with less fluctuations and DID being more similar to classical PD. Both of the mean ventricular CSF T-BP concentrations in the JP and classical PD patients were significantly lower than that in neurological controls. Moreover, the mean T-BP level in the JP-I was markedly lower than that in the JP-II or classical PD. Total biopterin levels revealed a gaussian distribution in the classical PD. However, a bimodal distribution was noted in the JP, with the lower peak consisting of only JP-I patients. These results seem to indicate that JP-II represents early-onset classical PD, while JP-I represents a distinct subgroup having a different physiopathology from classical PD.

Adult↗
PubMed1992

Significance of CSF total neopterin and biopterin in inflammatory neurological diseases.

Total neopterin (T-N), a by-product in the biopterin biosynthesis and an indicator of activation of the cellular immune system, and total biopterin (T-B) levels in cerebrospinal fluid (CSF), were measured in patients with various inflammatory neurological diseases and Parkinson's disease, and the following results were obtained. (1) In patients with neuro-sarcoidosis, neuro-Behçet's disease and meningitis, CSF T-N levels were markedly elevated in the exacerbation or acute stages of their neurological symptoms and remarkably decreased in the remission or chronic stages. In the neuro-sarcoidosis and neuro-Behçet's disease patients, however, CSF T-B levels showed no substantial change. (2) There was a significant positive correlation between CSF T-N levels and CSF/serum albumin ratios only in the meningitis patients. However, increases of CSF T-N levels were not associated with those of plasma T-N levels. (3) In the Parkinson's disease patients, CSF T-N levels remained normal, although CSF T-B levels significantly decreased. (4) A gradient for the CSF T-N value (lumbar greater than ventricular CSF), being reverse to the CSF T-B value, was observed. These results indicate that the significance of CSF T-N is quite different from CSF T-B, and that CSF T-N appears to be a valuable biochemical marker for evaluating the activity of inflammation within the central nervous system. Its measurement seems useful for therapeutic monitoring, especially of patients showing the chronic exacerbating-remitting course.

Adult↗
PubMed1992

Is Parkinson's disease a mitochondrial disorder?

Parkinson's disease (PD) is a common degenerative disease, but its etiology is still unknown. However, since the discovery of MPTP, many investigators have been interested in the mitochondrial function in PD. We investigated mitochondrial functions in PD patients using the methods which have successfully been applied to mitochondrial myopathies (MM), i.e. assay of lactate and pyruvate, measurement of muscle mitochondrial respiratory enzyme activities and Southern blot analysis of muscle mitochondrial DNA. Parkinson's disease patients did not differ from controls in the mean blood and CSF (cerebrospinal fluid) lactate and pyruvate levels at the basal resting state or during an aerobic exercise. But mitochondrial complex I activity of the skeletal muscle was significantly decreased in PD. In the Southern blot analysis, we could not find major deletions or insertions of mitochondrial DNA in PD. Our studies disclosed a differential mitochondrial impairment between PD and MM. We discuss the implication of our observation.

Aerobiosis↗
PubMed1992

Effect of insulin on impaired antioxidant activities in aortic endothelial cells from diabetic rabbits.

The defense system of aortic endothelial cells against oxidative stress was studied in alloxan-induced diabetic rabbits, and the effect of insulin on the antioxidant activities was estimated. Endothelial cells were prepared from 10 diabetic rabbits, 18 diabetic rabbits treated with insulin, and 10 age-matched controls after 17 days of diabetes. These cells were used for the estimation of glutathione (GSH) levels and its related enzyme activities. The antioxidant activities in these endothelial cells from diabetic rabbits were compared with those from control subjects. The concentration of GSH decreased in diabetic rabbits (1.6 +/- 0.2 nmol/mg protein [mean +/- SD] v 3.7 +/- 0.6 nmol/mg protein). Decreases in the activities of Cu, Zn-superoxide dismutase (Cu,Zn-SOD) (62.7 +/- 11.0 U/mg protein v 172.9 +/- 20.2 U/mg protein), catalase (7.6 +/- 2.1 U/mg protein v 12.3 +/- 3.2 U/mg protein), and GSH peroxidase (134.0 +/- 27.0 mU/mg protein v 179.1 +/- 26.2 mU/mg protein) were observed. The activities of other GSH-related enzymes such as GSH S-transferase or GSH reductase did not change in endothelial cells from diabetic rabbits. Most of these antioxidant activities were prevented when diabetic rabbits were treated with insulin (1 to 2 U/kg/d). These antioxidant activities were also determined in the diabetic liver and kidney. Similar decreases in the cellular defense activities and prevention of the decrease in activities by insulin were observed in the diabetic liver, while these antioxidant enzyme activities in the kidney were resistant to diabetic conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

K+ channel involvement in induction of synaptic enhancement by mast cell degranulating (MCD) peptide.

A bee venom, mast cell degranulating peptide (MCD), which induces long-term potentiation (LTP) of synaptic transmission in hippocampal slices, was found to possess multiple functions. They include (1) binding and thereby inhibiting a voltage-dependent K(+)-channel in brain membranes, (2) incorporation in a lipid bilayer to form voltage-dependent and cation-selective channels by itself, and (3) activation of a pertussis toxin (Ptx)-sensitive GTP-binding proteins. In this study, we prepared several derivatives and analogues of MCD and investigated which function is more closely related to the induction of LTP. Another bee venom, apamin, formed ion channels in a lipid bilayer which were indistinguishable from those formed by MCD. D-MCD, an optical isomer of MCD, activated a Ptx-sensitive GTP-binding protein. However, these peptides did not induce LTP in the hippocampal slices. A snake venom, dendrotoxin-I (DTX-I), bound to the same K(+)-channels as MCD and did induce LTP. These results suggest that the most potent aspect of MCD involved in LTP inducibility is its interaction with the voltage-dependent K(+)-channel.

Animals↗