[Thermography for diagnosis of breast cancers].
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Breast Neoplasms↗
Biomedical subjects
K Miyauchi
Publications and source records attributed to K Miyauchi.
PcpA, which is involved in the degradation of pentachlorophenol in Sphingomonas chlorophenolica ATCC39723, is a novel type of ring-cleavage dioxygenase.
The pentachlorophenol (PCP) mineralizing bacterium Sphingomonas chlorophenolica ATCC39723 degrades PCP via 2,6-dichlorohydroquinone (2,6-DCHQ). The pathway converting PCP to 2,6-DCHQ has been established previously; however, the pathway beyond 2,6-DCHQ is not clear, although it has been suggested that a PcpA plays a role in 2, 6-DCHQ conversion. In this study, PcpA expressed in Escherichia coli was purified to homogeneity and shown to have novel ring-cleavage dioxygenase activity in conjunction with hydroquinone derivatives, and converting 2,6-DCHQ to 2-chloromaleylacetate.
Amino Acid Sequence↗
Complete analysis of genes and enzymes for gamma-hexachlorocyclohexane degradation in Sphingomonas paucimobilis UT26.
gamma-Hexachlorocyclohexane (gamma-HCH; also called BHC or lindane) is one of the highly chlorinated pesticides which can cause serious environmental problems. Sphingomonas paucimobilis UT26 degrades gamma-HCH under aerobic conditions. The unique degradation pathway of gamma-HCH in UT26 is revealed. In the upstream pathway, gamma-HCH is transformed to 2,5-dichlorohydroquinone (2,5-DCHQ) by two different dehalogenases (LinA and LinB) and one dehydrogenase (LinC) which are expressed constitutively. In the downstream pathway, 2,5-DCHQ is reductively dehalogenated, and then ring-cleaved by enzymes (LinD and LinE, respectively) whose expressions are regulated. We have cloned and sequenced five structural genes (linA, linB, linC, linD, and linE) directly involved in this degradation pathway. The linD and linE genes form an operon, and its expression is positively regulated by the LysR-type transcriptional regulator (LinR). The genes linA, linB, and linC are constitutively expressed, and are present separately from each other in the UT26 genome. Cell fractionation analysis, Western blotting, and immuno electron microscopy revealed that LinA and LinB are localized in the periplasmic space of UT26.
Journal Article↗
Action of pyrroloquinolinequinol as an antioxidant against lipid peroxidation in solution.
The activities of pyrroloquinoline quinone (PQQ), a coenzyme of methanol dehydrogenase and amine oxidase, and its reduced form pyrroloquinoline quinol (PQQH2) as an antioxidant have been measured in solution. PQQH2 was stable in the absence of oxygen but rapidly auto-oxidized to PQQ in the presence of oxygen in water. PQQH2 was stable in an aprotic solvent such as acetonitrile, even in air. PQQ did not exert appreciable antioxidant activity, whereas PQQH2 exerted higher reactivity than alpha-tocopherol toward galvinoxyl radical and peroxyl radical. PQQH2 acted as a potent antioxidant against the oxidation of methyl linoleate in acetonitrile induced by azo compound and produced a clear induction period, from which the apparent stoichiometric number was obtained as 1.1. PQQH2 reduced the alpha-tocopheroxyl radical and spared alpha-tocopherol in the oxidation of methyl linoleate. These results suggest that PQQH2 may act as a potent antioxidant, particularly in combination with alpha-tocopherol.
Animals↗
Two different types of dehalogenases, LinA and LinB, involved in gamma-hexachlorocyclohexane degradation in Sphingomonas paucimobilis UT26 are localized in the periplasmic space without molecular processing.
gamma-Hexachlorocyclohexane (gamma-HCH) is one of several highly chlorinated insecticides that cause serious environmental problems. The cellular proteins of a gamma-HCH-degrading bacterium, Sphingomonas paucimobilis UT26, were fractionated into periplasmic, cytosolic, and membrane fractions after osmotic shock. Most of two different types of dehalogenase, LinA (gamma-hexachlorocyclohexane dehydrochlorinase) and LinB (1,3,4,6-tetrachloro-1,4-cyclohexadiene halidohydrolase), that are involved in the early steps of gamma-HCH degradation in UT26 was detected in the periplasmic fraction and had not undertaken molecular processing. Furthermore, immunoelectron microscopy clearly showed that LinA and LinB are periplasmic proteins. LinA and LinB both lack a typical signal sequence for export, so they may be secreted into the periplasmic space via a hitherto unknown mechanism.
Bacterial Proteins↗
Cloning and sequencing of a novel meta-cleavage dioxygenase gene whose product is involved in degradation of gamma-hexachlorocyclohexane in Sphingomonas paucimobilis.
Sphingomonas (formerly Pseudomonas) paucimobilis UT26 utilizes gamma-hexachlorocyclohexane (gamma-HCH), a halogenated organic insecticide, as a sole source of carbon and energy. In a previous study, we showed that gamma-HCH is degraded to chlorohydroquinone (CHQ) and then to hydroquinone (HQ), although the rate of reaction from CHQ to HQ was slow (K. Miyauchi, S. K. Suh, Y. Nagata, and M. Takagi, J. Bacteriol. 180:1354-1359, 1998). In this study, we cloned and characterized a gene, designated linE, which is located upstream of linD and is directly involved in the degradation of CHQ. The LinE protein consists of 321 amino acids, and all of the amino acids which are reported to be essential for the activity of meta-cleavage dioxygenases are conserved in LinE. Escherichia coli overproducing LinE could convert both CHQ and HQ, producing gamma-hydroxymuconic semialdehyde and maleylacetate, respectively, with consumption of O(2) but could not convert catechol, which is one of the major substrates for meta-cleavage dioxygenases. LinE seems to be resistant to the acylchloride, which is the ring cleavage product of CHQ and which seems to react with water to be converted to maleylacetate. These results indicated that LinE is a novel type of meta-cleavage dioxygenase, designated (chloro)hydroquinone 1, 2-dioxygenase, which cleaves aromatic rings with two hydroxyl groups at para positions preferably. This study represents a direct demonstration of a new type of ring cleavage pathway for aromatic compounds, the hydroquinone pathway.
Amino Acid Sequence↗
Effective intra-arterial chemotherapy for acinar cell carcinoma of the pancreas.
A 41-year-old man with a huge pancreatic tumor (acinar cell carcinoma) was treated by intra-arterial infusion chemotherapy with 5-fluorouracil (5-FU), mitomycin C (MMC) and cisplatin (CDDP). The tumor was significantly reduced, and he underwent a pancreaticoduodenectomy with complete excision of the tumor. Unfortunately multiple metastatic liver tumors were noted 5 months after resection. These tumors could also be markedly reduced by intra-arterial chemotherapy and the survival period was prolonged to 18 months. He suddenly died of sepsis but not from the pancreatic carcinoma. This case shows that intra-arterial infusion chemotherapy with 5-FU, MMC and CDDP can be an effective regimen for the treatment of acinar cell carcinoma of the pancreas.
Adult↗
[Effects of allopurinol for oxidative injury of cisplatin-induced nephrotoxicity in mice].
The effects of allopurinol (Allop) on the lipid peroxidation in the nephrotoxicity of an antitumor drug, cisplatin (CDDP) were studied in mice. CDDP was administered intraperitoneally to two groups (CDDP + Allop group and CDDP + CMC-Na group) at single doses of 10 mg/kg, and mice were sacrificed 3 days after CDDP administration. The body weights of the CDDP-administered group gradually decreased to approximately 78% of the values of the control group (saline + Allop group and saline + CMC-Na group) within 3 days. Plasma urea nitrogen and creatinine, especially in the CDDP + Allop group, increased after 3 days. Lipid peroxides in the blood and kidney were monitored by measuring the production of malondialdehyde (MDA), which increased in the CDDP + CMC-Na group. On the other hand, MDA levels in the CDDP + Allop group increased in the kidney but remained unchanged in the blood. Changes were observed in tissue glutathione (reduced form, GSH; oxidized form, GSSG) levels in the CDDP + Allop group but not in the CDDP + CMC-Na group. Histomorphological examination demonstrated the degeneration of the proximal tubuli in the CDDP-administered groups. Especially in the CDDP + Allop group, the increase of mesangium cells in the glomeruli was observed. From these results, it was suggested that Allop was not able to inhibit CDDP-induced lipid peroxidation in the kidney, and the kidney function became more severely impaired by the administration of Allop.
Allopurinol↗
Effects of the thromboxane A2 receptor antagonist on platelet deposition and intimal hyperplasia after balloon injury.
Thromboxane A2 (TXA2) after vascular injury plays an important role in the process of restenosis. S-1452, a potent and selective TXA2 receptor antagonist, blocks the receptors of vascular smooth muscle cells (VSMC) as well as platelets. The purpose of this study was to determine whether S-1452 could reduce platelet deposition and intimal hyperplasia in vascular injury models. New Zealand White Rabbits (n = 41) were fed a 0.5% cholesterol diet. For the short-term study, eighteen rabbits after balloon injury of iliac artery were assigned to 3 groups; systemic administration of S-1452, single local administration of S-1452 using a local delivery balloon, and single local administration of saline solution. Platelet deposition in injured artery using 111In-labeled platelets was reduced by 50% in systemic administration and by 60% in local administration compared to saline infusion. For the long-term study, balloon injury of the iliac artery was performed 4 weeks after starting the 0.5% cholesterol diet. Twenty-three rabbits were classified into 4 groups; systemic administration of S-1452, oral placebo administration, single local administration of S-1452, and local administration of saline solution (control group). The platelet aggregation induced by U-46619 was significantly lower in the S-1452 group than in the control group. Systemic administration of S-1452 significantly reduced the intimal area (152 +/- 33 vs 735 +/- 135 microm2, p < 0.001) and number of cells in the intima (513 +/- 57 vs 993 +/- 57, p < 0.01) compared to controls. In contrast, a single local administration failed to reduce neointimal thickness. Systemic administration of S-1452 reduced intimal hyperplasia as well as platelet deposition in a rabbit injury model, but its single local administration inhibited only platelet deposition.
Angioplasty, Balloon↗
Transmyocardial and percutaneous myocardial revascularization: current and future role in the treatment of coronary artery disease.
Transmyocardial revascularization (TMR) is a new treatment modality under evaluation in patients with severely symptomatic, diffuse coronary artery disease, in whom the potential for medical or interventional management has been exhausted. Preliminary clinical trials show improved ischemic symptoms within the first 3 months in about 70% of TMR-treated patients. The original proposed mechanism of surgical or catheter-based TMR (percutaneous myocardial revascularization [PMR]) was that channels mediate direct blood flow between the left ventricular cavity and ischemic myocardium. However, several alternative explanations for the clinical success of TMR have recently been suggested, including improved perfusion by angiogenesis, an anesthetic effect by nerve destruction, and a potential placebo effect. This article reviews the clinical role of TMR/PMR, its possible pathophysiologic mechanisms, and its controversies. It provides an overview of the actual scientific and clinical status of TMR and details future directions.
Angioplasty, Balloon, Coronary↗
Effect of the lipid peroxide reaction caused by repeated cold stress on cisplatin-induced nephrotoxicity.
The peroxide reaction in mouse kidney was examined in order to determine the relationship between the lipid peroxide reaction caused by SART (specific alternation of rhythm in temperature) stress and that caused by drug administration. After exerting SART stress for one wk on 6-wk-old male ddY mice (stress group), the peroxide reaction generated by the administration of a single dose of cis-diamminedichloroplatinum (cisplatin: CDDP, 10 mg/kg, i.p.) into SART-stressed mice (stress + CDDP group) was compared with the reaction of CDDP-administered nonstressed mice (CDDP group), saline-administered nonstressed mice (saline group), and saline-administered SART-stressed mice (stress + saline group). Lipid peroxidation in the kidneys was significantly higher in the stress group upon cessation of stress exertion than in the normal group. However, no significant difference in the lipid peroxide level after administration of CDDP was observed between the CDDP groups. The renal glutathione levels were significantly different between the CDDP groups and the saline administered groups. These results indicate that the peroxide reaction is generated in the kidneys by stress, but stress has no effect on the peroxide damage caused by CDDP administration. However, the contribution of stress to renal function impairment requires further evaluation.
Animals↗
Experimental hypercholesterolemia induces ultrastructural changes in the internal elastic lamina of porcine coronary arteries.
The internal elastic lamina (IEL) serves as a barrier for cells and macromolecules migration between the intima and the media in the vascular wall. Several investigators have reported internal elastic lamina ultrastructural changes in elastic arteries with atherosclerosis. However, no quantitative and qualitative assessment of the internal elastic lamina architecture in muscular arteries such as the coronary circulation during early atherosclerosis have been performed yet. In this study, we therefore evaluated the ultrastructural morphological changes of the IEL in the coronary circulation of pigs fed with high cholesterol diet. Animals were sacrificed after being fed either a high cholesterol diet for 10-12 weeks (n = 5, 12 coronary segments) or a control diet (n = 4, 15 coronary segments). Coronary arteries were analyzed by transmission and scanning electron microscopy. In addition, computerized digital analysis of the images obtained by confocal scanning microscopy was performed for the quantitation of the morphologic changes in the internal elastic lamina. Confocal microscopy and scanning electron microscopy revealed an altered pattern characterized by large oval fenestration formation in the internal elastic lamina of hypercholesterolemic animals. Computerized morphometric analysis of confocal microscopy images demonstrated that compared to controls, the IEL of cholesterol-fed animals was characterized by an increase in the minor diameter of the fenestrae (2.16 +/- 0.04 microm versus 3.32 +/- 0.06 microm, P = 0.003) and a decrease in the fenestrae density (22333 +/- 1334/mm2 versus 17552 +/- 931/mm2, P = 0.015) of the internal elastic lamina. The percentage of the IEL area covered by the fenestrae correlated with the intimal thickness (r = 0.79, P = 0.004). This study demonstrates that experimental hypercholesterolemia is characterized by ultrastructural changes of the internal elastic lamina in the coronary circulation. This study suggests that the IEL may play an important role in the development of structural changes which characterize the early phase of coronary atherosclerosis.
Animals↗
Treatment of ameloblastoma in children.
Clinicopathological data were collected for six children with ameloblastoma less than 16 years old. They were all treated initially by conservative surgery and satisfactory results without jaw deformities were finally attained. One of the histological characteristics of ameloblastoma in children is the prevalence of the plexiform type, which is thought to behave less aggressively than the follicular type. Conservative treatment is acceptable initial treatment of ameloblastoma in children who can be followed up in a precise, detailed manner.
Adolescent↗
Effect of probucol on smooth muscle cell proliferation and dedifferentiation after vascular injury in rabbits: possible role of PDGF.
We previously reported a clinical study in which probucol reduced the restenosis rate. The mechanism of this effect is unclear. Restenosis is characterized by neointimal hyperplasia caused by proliferation of smooth muscle cells (SMCs), which increases the expression of Platelet-derived growth factor (PDGF)-A and SMemb. SMemb, a non-muscle-type myosin heavy chain most predominantly expressed in embryonic smooth muscle, can be used as a good molecular marker for dedifferentiated SMC. The aim of this study was to analyze the effect of probucol on neointimal proliferation and the level of expression of PDGF-A and SMemb after balloon injury in rabbits. Probucol was given orally 1.3 g/d from 2 weeks prior to carotid balloon injury to the time of killing (2 or 4 weeks after balloon injury). Intimal area was determined histologically using a computerized morphometry program. For quantification of SMC proliferation, alpha-actin-positive cells and proliferating cell nuclear antigen (PCNA)-labeled cells were counted. The expression of PDGF-A and SMemb mRNA was analyzed by the RNase protection assay. SMemb expression was also examined by immunohistochemistry. Probucol remarkably decreased intimal area by 70% and the number of SMC and PCNA-labeled cells in the intima. The expression of PDGF-A mRNA was significantly increased after balloon injury in untreated rabbits, whereas it was markedly suppressed with probucol treatment. The expression of SMemb was significantly increased in injured arteries at mRNA and protein levels. However, probucol did not suppress SMemb expression. Probucol is effective in preventing SMC proliferation, which is possibly due to a decrease in the expression of PDGF.
Angioplasty, Balloon↗
A case of pedunculated tubulovillous adenoma of the duodenum.
Tubulovillous adenoma of the duodenum is a rare tumor. Almost all of the lesions have been reported endoscopically and are recognized as small, sessile, polypoid lesions. This article discusses an unusual case of pedunculated tubulovillous adenoma of the duodenum in a 48-yr-old woman. The lesion was discovered on the upper part of the descending duodenum during a gastric mass survey. The polyp was removed using an electrocautery snare and was histologically diagnosed as tubulovillous adenoma.
Adenoma, Villous↗
Cloning and sequencing of a 2,5-dichlorohydroquinone reductive dehalogenase gene whose product is involved in degradation of gamma-hexachlorocyclohexane by Sphingomonas paucimobilis.
Sphingomonas (formerly Pseudomonas) paucimobilis UT26 utilizes gamma-hexachlorocyclohexane (gamma-HCH), a halogenated organic insecticide, as a sole carbon and energy source. In a previous study, we showed that gamma-HCH is degraded to 2,5-dichlorohydroquinone (2,5-DCHQ) (Y. Nagata, R. Ohtomo, K. Miyauchi, M. Fukuda, K. Yano, and M. Takagi, J. Bacteriol. 176:3117-3125, 1994). In the present study, we cloned and characterized a gene, designated linD, directly involved in the degradation of 2,5-DCHQ. The linD gene encodes a peptide of 343 amino acids and has a low level of similarity to proteins which belong to the glutathione S-transferase family. When LinD was overproduced in Escherichia coli, a 40-kDa protein was found after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Northern blot analysis revealed that expression of the linD gene was induced by 2,5-DCHQ in S. paucimobilis UT26. Thin-layer chromatography and gas chromatography-mass spectrometry analyses with the LinD-overexpressing E. coli cells revealed that LinD converts 2,5-DCHQ rapidly to chlorohydroquinone (CHQ) and also converts CHQ slowly to hydroquinone. LinD activity in crude cell extracts was increased 3.7-fold by the addition of glutathione. All three of the Tn5-induced mutants of UT26, which lack 2,5-DCHQ dehalogenase activity, had rearrangements or a deletion in the linD region. These results indicate that LinD is a glutathione-dependent reductive dehalogenase involved in the degradation of gamma-HCH by S. paucimobilis UT26.
Amino Acid Sequence↗
Local delivery infusion pressure is a key determinant of vascular damage and intimal thickening.
Local drug delivery following percutaneous transluminal coronary angioplasty (PTCA) may prevent restenosis by achieving higher local tissue concentrations of drugs than systemic administration. However, it remains unknown whether vascular damage and the ensuing intimal thickening is associated with the degree of infusion pressure achieved by local delivery. Therefore, local delivery of normal saline was performed using a channeled balloon catheter (Transport) to the rabbit iliac artery with different infusion pressures of 0, 3, 5, 7, and 12 atm (n=4 for each). The extent of vascular damage and the development of intimal thickening were determined histopathologically 14 days after the procedure. In 10 additional rabbits, to assess the degree of vessel penetration, local delivery of indocyanine green dye solution was performed in a similar fashion. After 1 h, the green dye penetrated deeply at the higher infusion pressures of 7 and 12 atm. The incidence of internal clastic lamina laceration and occurrence of total occlusion as a result of thrombus formation demonstrated an increase proportional to the degree of local infusion pressure. When the vascular injury score in each arterial section was plotted against the infusion pressure, a significant relation was observed (r=0.717, p<0.0001). At 0, 3, 5, 7, and 12 atm, neointimal areas of 0.160+/-0.005, 0.163+/-0.008, 0.189+/-0.017, 0.260+/-0.027, and 0.329+/-0.033 mm2, respectively, were observed. Smooth muscle cell (SMC) proliferative activity also increased in proportion to the local infusion pressure. We have demonstrated for the first time that local delivery infusion pressure itself is related to the severity of vascular damage, resulting in the development of intimal thickening and an associated increase in SMC proliferative activity. Therefore, we suggest that infusion pressure is a key determinant of vascular injury during local drug delivery, with lower pressure causing the least neointimal response.
Angioplasty, Balloon, Coronary↗
Limitations of angiotensin-converting enzyme inhibitor in restenosis of a deep arterial injury model.
Cilazapril (CLZ) has been reported to reduce intimal hyperplasia in a rat carotid model of restenosis. The purpose of this study was to determine whether CLZ inhibits restenosis after deep arterial injury in lathyritic rats. The lathyritic rat was used as a model of deep arterial injury; in this model the internal elastic lamina is easily broken by balloon injury because of the fragility of the connective tissue. Deep arterial injury is defined as rupture of the internal elastic lamina with damage to both the intima and the media. The rats were divided into 4 groups (n = 40): mild injury (intimal damage with intact internal elastic lamina), mild injury +CLZ, deep injury, and deep injury +CLZ. In the CLZ-treated groups, the drug was administered orally (10 mg/day) from 7 days before balloon injury until the time of sacrifice 21 days after balloon injury. The intimal hyperplasia was determined histologically using a computerized morphometry program. At sacrifice, blood pressure was lower in the CLZ-treated groups than in the untreated (control) rats (p < 0.05). In the mild injury model, CLZ decreased intimal hyperplasia markedly. In contrast, CLZ failed to reduce intimal hyperplasia in the rats with deep injury. CLZ markedly decreased neointimal hyperplasia in mild injury. In contrast, CLZ failed to reduce intimal area in deep injury. The type of arterial injury seems to determine the effectiveness of CLZ.
Angioplasty, Balloon↗