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Biomedical subjects

K Uchida

Publications and source records attributed to K Uchida.

At least 109 records · Page 6Linked to original sources
PubMed2001

Cyclopentenone prostaglandins as potential inducers of intracellular oxidative stress.

In the present study, we find that cyclopentenone prostaglandins (PGs) of the J(2) series, naturally occurring derivatives of PGD(2), are potential inducers of intracellular oxidative stress that mediates cell degeneration. Based on an extensive screening of diverse chemical agents on induction of intracellular production of reactive oxygen species (ROS), we found that the cyclopentenone PGs, such as PGA(2), PGJ(2), Delta(12)-PGJ(2), and 15-deoxy-Delta(12,14)-PGJ(2), showed the most potent pro-oxidant effect on SH-SY5Y human neuroblastoma cells. As the intracellular events that mediate the PG cytotoxicity, we observed (i) the cellular redox alteration represented by depletion of antioxidant defenses, such as glutathione and glutathione peroxidase; (ii) a transient decrease in the mitochondrial membrane potential (Deltapsi); (iii) the production of protein-bound lipid peroxidation products, such as acrolein and 4-hydroxy-2-nonenal; and (iv) the accumulation of ubiquitinated proteins. These events correlated well with the reduction in cell viability. In addition, the thiol compound, N-acetylcysteine, could significantly inhibit the PG-induced ROS production, thereby preventing cytotoxicity, suggesting that the redox alteration is closely related to the pro-oxidant effect of cyclopentenone PGs. More strikingly, the lipid peroxidation end products, acrolein and 4-hydroxy-2-nonenal, detected in the PG-treated cells potently induced the ROS production, which was accompanied by the accumulation of ubiquitinated proteins and cell death, suggesting that the membrane lipid peroxidation products may represent one of the causative factors that potentiate the cytotoxic effect of cyclopentenone PGs by accelerating intracellular oxidative stress. These data suggest that the intracellular oxidative stress, represented by ROS production/lipid peroxidation and redox alteration, may underlie the well documented biological effects, such as antiproliferative and antitumor activities, of cyclopentenone PGs.

Aldehydes↗
PubMed2001

Fragment-specific actions of parathyroid hormone in isolated perfused rat hearts.

Different regions within the parathyroid hormone (PTH) molecule are known to have different biological activities. In the heart, the physiological actions of the intact PTH molecule are known as positive chronotropy and coronary vasodilatation. However, it is unclear which region of the PTH exerts which physiological action in the heart. Therefore, to clarify this point, we examined the hemodynamic effect of intact PTH(1-84) and selected PTH analogs, namely, PTH(1-34), PTH(2-34), [Nle8, 18Tyr34]PTH(3-34), PTH(4-34), [Tyr34]PTH(7-34), and PTH(13-34) in isolated perfused rat hearts. Both PTH(1-84) and PTH(1-34) significantly increased heart rate and decreased coronary perfusion pressure. In contrast, neither PTH(2-34) nor [Nle8,18Tyr34]PTH(3-34) increased heart rate, but they did decrease coronary perfusion pressure. Peptides further truncated at the amino terminus, PTH(4-34), [Tyr34]PTH(7-34), and PTH(13-34), had no effect on hemodynamics. Furthermore, the protein kinase A inhibitor H89, but not the protein kinase C inhibitor H7, attenuated the hemodynamic effects of PTH(1-34) or PTH(2-34), while it prevented those of [Nle8,18Tyr34]PTH(3-34). These results clearly demonstrate that the first amino acid of PTH is essential for its chronotropic property whereas the first 3 amino acids of PTH are involved in its coronary vasodilatory action. Furthermore, protein kinase A, but not protein kinase C, appears to be involved in the chronotropic and coronary vasodilatory actions of PTH.

Animals↗
PubMed2001

Three-dimensional structures of canine senile plaques.

In this study, the three-dimensional structures of two types of canine senile plaques (SP), diffuse plaques (DP) and mature plaques (MP), were compared using a confocal laser scanning microscope. The three-dimensional observation revealed that canine DP were uneven nebula-like assemblies of amyloid-beta (Abeta), while MP were comparatively uniform assemblies of membrane-like or fibrous Abeta materials with some differences among subtypes (primitive, classic and compact). We also noticed the presence of areas with low-density Abeta deposition inside DP and MP, indicating degradation of Abeta. Double staining for Abeta and other SP constituents was also conducted. Amyloid precursor protein (APP) was mainly deposited as rough granules around Abeta assemblies in DP and both inside and around Abeta assemblies in MP. The patten of ubiquitin deposition was quite similar to that of APP. Glial fibrillary acidic protein-positive astroglial projections were found around and inside Abeta assemblies in both types of SP, but were more prominent in MP than DP. DP were often invaded by neurofilament-positive neuronal processes (neurites), while no such neurites were observed inside MP. Dystrophic neurites were, however, frequently detected around MP. These results clearly showed that canine DP and MP have completely different three-dimensional structures, consistent with different processes of DP and MP formation.

Aging↗
PubMed2001

Immunohistochemical detection of lipid peroxidation products, protein-bound acrolein and 4-hydroxynonenal protein adducts, in actinic elastosis of photodamaged skin.

Acrolein and 4-hydroxy-2-nonenal (HNE) are both byproducts of a lipid peroxidation reaction. Actinic elastosis in photodamaged skin of aged individuals is characterized by the accumulation of fragmented elastic fibers in the sun-exposed areas. To study whether a lipid peroxidation reaction is involved in the accumulation of altered elastic fibers in actinic elastosis, skin specimens obtained from sun-damaged areas were immunohistochemically examined using the antibodies against acrolein and HNE. Both antibodies were found to react with the accumulations of elastic material. Double immunofluorescence labeling demonstrated that acrolein/elastin and HNE/elastin were colocalized in the actinic elastosis. Western blot analysis showed that the polypeptide with a molecular weight of 62 kDa reacted with anti-acrolein, anti-HNE and anti-elastin antibodies. The results suggest that acrolein and HNE may be associated with actinic elastosis.

Acrolein↗
PubMed2001

Characteristics of the cell proliferation profile of activated rat hepatic stellate cells in vitro in contrast to their fibrogenesis activity.

PURPOSE: Alterations in the kinetics of hepatic stellate cells (HSCs) after the cells are activated once have not been well documented. We investigated the characteristic profiles of cell proliferation of once-activated HSCs in contrast to the in fibrogenesis activity. METHODS: HSCs from male Wistar rats were submitted to primary culture for 14 days and to secondary culture for 7 days. The potential for cell proliferation was evaluated by the number of the cells in G2/M phase, based on flow cytometric analysis of the cell cycle. The fibrogenesis activity was assessed by Northern blot analysis of the expression of type I and type III procollagen mRNA. RESULTS: The number of HSCs in G2/M phase was maintained at a low level in primary culture after 6 days, while a significantly (P < 0.05) elevated number of HSCs in G2/M phase was observed on days 3 to 4. In secondary culture, the number of HSCs in G2/M phase was also consecutively maintained at a decreased level. By contrast, HSCs showed progressively increased type I and type III procollagen mRNA expression during the experimental periods of primary culture. CONCLUSIONS: These results clearly demonstrated consecutively decreased proliferative activity, evaluated by the potential for cell mitogenesis, in once-activated HSCs, in contrast to their progressively increased fibrogenesis activity.

Animals↗
PubMed2001

Cultured human foetal cerebral cortex, transfected with tyrosine hydroxylase cDNA, as a source of neural transplant material.

Obtaining an adequate supply of foetal dopaminergic tissue to treat Parkinson's disease by neural transplantation can be difficult. In this study primary cultures of human foetal cerebral cortex cells were transfected, using cationic lipids, with a eukaryotic expression vector (pCIneo-THI) containing the cDNA for human tyrosine hydroxylase isoform I (TH). Cortical cells from human (10-14 week) foetuses were cultured for 11 days in vitro and transfected twice with pCIneo-THI during this time. The double transfection process resulted in 3-4% of the cells becoming TH positive. When grafted into the striatum of 6-OHDA lesioned rats the transfected foetal cerebral cortex cells reduced amphetamine-induced circling behaviour by 75%, while grafts of untransfected cells had no significant effect on turning. TH transfected foetal cerebral cortex cells may therefore be a useful alternative supply of tissue for use in neural transplants to treat Parkinson's disease.

Adrenergic Agents↗
PubMed2001

Gait analysis of spastic walking in patients with cervical compressive myelopathy.

To assess neurological status and to evaluate the effect of surgical decompression in patients with cervical myelopathy, we performed computerized gait analysis in 24 patients with cervical compressive myelopathy who showed spastic walking. Gait analysis was repeated during neurological follow-up that averaged 32.4 months. The gait pattern in patients with severe myelopathy was characterized by hyperextension of the knee in the stance phase without plantar flexion of the ankle in the swing phase, significantly reduced walking speed and step length, prolonged stance phase duration and decreased single-stance phase duration, and increased step width. The angle of flexion of the knee joint in the stance phase was significantly correlated with the Japanese Orthopaedic Association (JOA) score. Postoperative neurological improvement was associated with increased walking speed and decreased extension angle of the knee joint (single-stance phase and swing phase). Postoperatively, 12 patients had normalized extension of the knee in stance phase and their walking speed, cadence, stance phase duration, and single-stance phase duration, as well as step length and width, showed nonsignificant differences from these parameters in healthy controls. Our results show that kinesiological gait analysis is clinically useful for the functional assessment of the severity of spastic walking in cervical myelopathy.

Adult↗
PubMed2001

In vitro antifungal activity of posaconazole against various pathogenic fungi.

The antifungal activity of posaconazole (SCH56592), a new triazole antifungal, against stock cultures and fresh clinical isolates of a wide range of pathogenic fungi was compared with that of itraconazole, fluconazole and amphotericin B. Posaconazole inhibited growth of all the fungal species tested except Fusarium spp. at 1 mg/l or lower concentrations, showing a broad-spectrum antifungal activity. The activities of posaconazole for all the fungal species far surpassed those of fluconazole and were even superior to those of itraconazole for Aspergillus spp. as well as for many other fungal species.

Antifungal Agents↗
PubMed2001

Evidence that malondialdehyde-derived aminoenimine is not a fluorescent age pigment.

It has been suggested that protein modifications by malondialdehyde (MDA), a major product of lipid peroxidation, contribute to the fluorescence formation of lipofuscin. Although early studies proposed an aminoenimine structure (RNHCH=CHCH=NR) formed from MDA and the epsilon-amino groups of the lysine residues for the fluorophores, there has been considerable doubt as to whether the aminoenimine is fluorescent. To date, however, there is no conclusive evidence that the aminoenimine is nonfluorescent. This is because that it has not yet been isolated. In this study, we succeeded in isolating an aminoenimine, N,N'-bis[5-(tert-butoxycarboxamido)-5-carboxypentyl]-1-amino-3-iminopropene [(Boc-Lys)(2)MDA], formed from the reaction of MDA with a lysine derivative, N(alpha)-tert-butoxycarbonyl-L-lysine (Boc-Lys), at neutral pH, and confirmed that the purified (Boc-Lys)(2)MDA exhibited no fluorescence. This result demonstrates that aminoenimines formed from MDA and lysine residues do not contribute to the fluorescence formation of lipofuscin.

Chromatography, High Pressure Liquid↗
PubMed2001

Chronic cyclosporin nephropathy: long-term effects of cyclosporin on renal allografts.

Cyclosporin (CSA) has significantly reduced both incidence and severity of acute rejection, and brought excellent graft survival rates. Chronic CSA nephrotoxicity seems to be the second most important diagnosis responsible for the late graft failure. CSA-associated arteriolopathy (CAA) is well known as a characteristic lesion of chronic CSA nephrotoxicity by graft biopsies. There are few reports on the long-term outcome of renal transplant patients with biopsy-proven chronic CSA nephrotoxicity after diagnosis of CAA. We conducted two studies, the long-term outcome of the patients with CAA, and the FGS lesion related to CAA. Seventy-four CAA patients continued on CSA therapy after diagnosis of CAA were classified into two groups by outcome of the graft after follow-up: the functioning graft group (n = 30) and the graft-loss group (n = 44). There was no significant difference in severity of CAA grade between the functioning and graft-loss groups. Concomitant lesion of chronic rejection but not severity of CAA was the most important risk factor of graft loss for CAA patients in our study. Of a total of 54 recipients with FGS lesion, 32 patients (59%) were diagnosed as CAA-associated glomerulopathy (CAG) accompanied with severe CAA. Eighteen of 32 CAG patients lost their grafts after follow-up. Their serum creatinine level at biopsy was higher than that of the functioning group; however, there was no significant difference in daily proteinuria at biopsy between two groups. We have tried to reduce CSA dosage to maintain lower blood levels than the usual optimal target levels, but did not discontinue CSA after diagnosis of severe CAA and FGS lesion. In 15 isolated pure CAG patients, those with increasing daily proteinuria exceeding 2 g lost their graft function even after reducing CSA administration. The change in daily proteinuria seems to be a useful indicator for late graft loss in the patients of FGS lesion with severe CAA. CAA is not specific for chronic CSA nephrotoxicity, and FGS lesion is also a non-specific lesion often developed in renal allografts. Our study revealed clinicopathological characteristics of chronic CSA nephrotoxicity. Isolated chronic CSA arteriolopathy of severe degree has a fairly good prognosis under controlled CSA therapy. FGS lesion accompanied by CAA is considered as a new concept of CAG, and increasing proteinuria in patients with CAG is a good indicator for poor outcome. These results will contribute towards an appropriate therapeutic plan for renal transplant patients undergoing long-term CSA treatment.

Adult↗
PubMed2001

Does infiltration of neutrophils in peritubular capillaries indicate humoral rejection? A case displaying a characteristic lesion of a significantly high amount of neutrophils in peritubular capillaries at 1-h graft biopsy during transplant operation.

We present a case report of a 50-yr-old Japanese woman with a significant accumulation of neutrophils in the peritubular capillaries (PTC) and severe acute tubular necrosis (ATN) at 1-h allograft biopsy during transplant operation from cadaver donor after a cardiac death. Significant accumulation of neutrophils in the PTC is usually valuable diagnostically for acute humoral rejection. However, the patient showed no clinical signs of acute rejection. A second graft biopsy performed on the fifth postoperative day (POD) revealed that both infiltration of neutrophils in PTC and ATN lesions were more aggravated. Neither clinical course nor other morphological findings were compatible with humoral rejection. After the third biopsy of POD 27 revealing acute vascular rejection of moderate degree, acute rejection therapy using methylprednisolone pulse therapy and OKT-3 therapy was performed. Consequently, after a period of delayed graft function requiring haemodialysis for approximately 4 wk, graft function was restored and serum creatinine decreased to 2 mg/dL. Later, we were able obtain information from a paired graft from the same donor. Significant accumulation of neutrophils in the PTC similar to our recipient was also noted in a 1-h biopsy specimen of the paired kidney. This confirmed that the accumulation of neutrophils in the PTC noted in two recipients was transmitted from the donor kidney. The pathogenesis and clinical significance of neutrophils in the PTC has been shrouded in mystery.

Biopsy↗
PubMed2001

Carboxyl proteinase from Pseudomonas defines a novel family of subtilisin-like enzymes.

The crystal structure of a pepstatin-insensitive carboxyl proteinase from Pseudomonas sp. 101 (PSCP) has been solved by single-wavelength anomalous diffraction using the absorption peak of bromide anions. Structures of the uninhibited enzyme and of complexes with an inhibitor that was either covalently or noncovalently bound were refined at 1.0-1.4 A resolution. The structure of PSCP comprises a single compact domain with a diameter of approximately 55 A, consisting of a seven-stranded parallel beta-sheet flanked on both sides by a number of helices. The fold of PSCP is a superset of the subtilisin fold, and the covalently bound inhibitor is linked to the enzyme through a serine residue. Thus, the structure of PSCP defines a novel family of serine-carboxyl proteinases (defined as MEROPS S53) with a unique catalytic triad consisting of Glu 80, Asp 84 and Ser 287.

Amino Acid Sequence↗
PubMed2001

Dizocilpine but not ketamine reduces the volume of ischaemic damage after acute subdural haematoma in the rat.

BACKGROUND AND OBJECTIVE: Increased glutamate concentration in the cerebrospinal fluid has been reported in severely head-injured patients, suggesting that an excessive release of glutamate may be involved in the process of neuronal damage. Ischaemic damage after subdural haematoma has been reported to be reduced by glutamate (N-methyl-D-aspartate: NMDA) receptor antagonists such as dizocilpine and CGS 19755; even though these drugs were given 20-30 min after insult. Excessive release of excitatory amino acids may produce the neural damage after subdural haematoma and NMDA receptor antagonists may become valuable therapeutic drugs. This study compared the effects of ketamine and dizocilpine, on intracranial pressure and histopathological changes after acute subdural haematoma produced by an injection of autologous blood (150 microL) in rats. METHODS: The control (n = 9), ketamine (n = 9) and dizocilpine (n = 9) groups, respectively, received saline, ketamine (total dose: 210 mg kg-1) or dizocilpine (total dose: 1.0 mg kg-1) from 0.5 to 8 h after acute subdural haematoma. A silicone group (n = 9) had the same volume of silicone injected subdurally. RESULTS: The volume of ischaemic damage in the silicone group (1.3 +/- 1.2 mm3) was significantly smaller than in the control group (11.9 +/- 3.8 mm3). Ketamine and dizocilpine did not increase intracranial pressure. Dizocilpine significantly decreased the volume of ischaemic damage (6.1 +/- 3.8 mm3). Ketamine failed to significantly decrease damage (7.8 +/- 5.0 mm3). CONCLUSIONS: These results suggest that the factors elicited by the clotted blood contribute to the ischaemic damage after subdural haematoma, and that the glutamate receptor antagonist dizocilpine reduces the damage, while ketamine shows only a trend reduction of the damage.

Animals↗
PubMed2001

In-vitro and in-vivo anti-Trichophyton activity of essential oils by vapour contact.

The minimum inhibitory doses (MIDs) of essential oils by vapour contact to inhibit the growth of Trichophyton mentagrophytes and Trichophyton rubrum on agar medium were determined using airtight boxes. Among seven essential oils examined, cinnamon bark oil showed the least MID, followed by lemongrass, thyme and perilla oils. Lavender and tea tree oils showed moderate MID, and citron oil showed the highest MID, being 320 times higher than that of cinnamon bark oil. The MID values were less than the minimum inhibitory concentration (MIC) values determined by agar dilution assay. Furthermore, the minimum agar concentration (MAC) of essential oils absorbed from vapour was determined at the time of MID determination as the second antifungal measure. The MAC value by vapour contact was 1.4 to 4.7 times less than the MAC remaining in the agar at the time of MIC determination by agar dilution assay. Using selected essential oils, the anti-Trichophyton activity by vapour contact was examined in more detail. Lemongrass, thyme and perilla oils killed the conidia, inhibited germination and hyphal elongation at 1-4 micrograms ml-1 air, whereas lavender oil was effective at 40-160 micrograms ml-1 air. The in-vivo efficacy of thyme and perilla oils by vapour contact was shown against an experimental tinea pedis in guinea pigs infected with T. mentagrophytes. These results indicated potent anti-Trichophyton action of essential oils by vapour contact.

Agar↗
PubMed2001

Therapeutic effects on intestinal Behçet's disease of an intravenous drug delivery system using dexamethasone incorporated in lipid emulsion.

Recurrent intestinal ulcer is a frequent problem in the management of Behçet's disease. However, no standard therapy for intestinal Beheçt's disease has been established. We report two patients with intestinal Behçet disease and recurrent ileal ulcers who were treated successfuly with a lipid emulsion of dexamethasone. In one patient, the cecal ulcer did not relapse after the intravenous administration initiation of a lipid emulsion of dexamethasone once a week, despite the discontinuation of prednisolone. In the other patient, the cecal ulcer showed a healing tendency, and oral administration of prednisolone was reduced from 40 to 15 mg/day after intravenous administration of a lipid emulsion of dexamethasone. Both patients experienced no complications associated with the administration of the emulsion. These results suggest that an intravenous drug delivery system using a lipid emulsion of dexamethasone is useful for treatment of intestinal Behçet's disease.

Anti-Inflammatory Agents↗