Biomedical subjects

M Miki

Publications and source records attributed to M Miki.

At least 109 records · Page 6Linked to original sources

PubMed1994

Homocysteine induces iron-catalyzed lipid peroxidation of low-density lipoprotein that is prevented by alpha-tocopherol.

Homocystinuria is an inborn error of methionine metabolism that is characterized by the premature development of arteriosclerosis. As one of the major factors in the pathogenesis of arteriosclerosis, modification of low-density lipoprotein (LDL) has received widespread attention by many investigators. In this study, to elucidate the relationship between elevated homocysteine levels and premature arteriosclerosis, we investigated the role of homocysteine in the iron-catalyzed oxidative modification of LDL. When LDL isolated from a healthy subject was incubated with homocysteine and ferric ion, a gradual decrease of polyunsaturated fatty acids (PUFA), formation of thiobarbituric acid-reactive substances (TBARS) and fluorescent substances, and the fragmentation of apoprotein B (apoB) were observed. The extent of oxidative modification was dependent on the concentration of homocysteine. Modification of LDL was suppressed until the remaining alpha-tocopherol concentration reached a critical level. When the alpha-tocopherol content of LDL was increased by 2.6-fold, both the formation of TBARS and the fragmentation of apoB were suppressed. These results suggest that homocysteine might promote iron-catalyzed oxidation of LDL and imply its role for the development of premature arteriosclerosis.

Adult↗

PubMed1994

[Flare response on bone scintigraphy in metastatic prostate cancer].

Seventy-seven cases of prostate cancer were treated for 5 years at our department and all cases were followed by bone scintigraphy and tumor markers. Of these cases on case of flare response on bone scintigraphy was recognized. A 51-year-old man was hospitalized with chief complaint of lumbago. Serum PAP and gamma-Sm levels were 320 ng/ml and 15 ng/ml, respectively. Prostate biopsy revealed moderately differentiated adenocarcinoma. Bone scintigraphy and CT scan demonstrated multiple bone metastases and lymph nodes involvements. Treatment was started with diethylstilbestrol diphosphate (DES). At one month after the initiation of treatment tumor markers fell down to the normal level and lumbago was diminished, but only serum alkaline phosphatase was elevated and bone scintigraphy showed apparent progression of individual lesions (flare response). The treatment was not altered. At the times after 2, 8, 12 and 36 months successful treatment the bone imaging improved with reduced tracer uptake and no new lesions. The flare response is a healing reaction and is followed apparent improvement. In general, serial bone scintigrams accurately depict the activity of bone metastases in the patients of prostate cancer, but between 1 and 3 months after starting treatment the paradoxical "flare phenomenon" should be taken care.

Adenocarcinoma↗

PubMed1994

[A case of multilocular cystic renal cell carcinoma diagnosed by pharmacoangiography].

A case of multilocular cystic renal cell carcinoma in a 62-year-old man was reported. He was admitted with complaint of asymptomatic gross hematuria. Abdominal ultrasonography and CT scan revealed multilocular cystic mass at the lower pole of the right kidney. Pharmacoangiography demonstrated tumor stain in the mass clearly. Radical nephrectomy was performed and histological diagnosis was multilocular cystic renal cell carcinoma; cystic type, clear cell subtype, G1 pT2b pV0 pN0. It is relatively difficult to diagnose multilocular cystic renal cell carcinoma but pharmacoangiography was very effective for diagnosis. Renal cell carcinoma related multilocular cyst were relatively rare. Eighty-nine cases reported in Japanese literatures were discussed statistically.

Angiography, Digital Subtraction↗

PubMed1994

Assessment of vitamin E nutritional status in neonates, infants and children--on the basis of alpha-tocopherol levels in blood components and buccal mucosal cells.

We examined the age-related changes of alpha-tocopherol levels in various clinically available biosamples in order to assess the vitamin E nutritional status. During the first week of life, more than half of every sample except red blood cells showed alpha-tocopherol levels below the lower limit of normal in a control group of children aged 3-16 years. alpha-Tocopherol levels in mononuclear leucocytes and buccal mucosal cells, which possess LDL receptors, increased in response to the plasma alpha-tocopherol elevation within a week after birth. However, RBC and platelet levels did not respond so quickly. Considering the transfer of tocopherol into body tissues during LDL catabolism, the determination of tocopherol levels in cells with LDL receptors may be useful for assessing the vitamin E status and our present study suggests that the tissue vitamin E status may be marginal in neonates.

Adolescent↗

PubMed1994

[Two cases of testicular tumor with brain metastasis].

During the last 8 years, 70 cases of testicular tumor were treated in our department. Of them 2 cases had brain metastasis. Case 1; A 37-year-old male was admitted with the chief complaint of cough. Retroperitoneal lymph node and lung metastases were discovered (stage IIIB, pT4aN1M1). Resected right testis was diagnosed as embryonal carcinoma, teratoma and STGC histopathologically. After 3 courses of PVB (cisplatinum, vincristine, bleomycin) chemotherapy right hemiplegia occurred and computerized tomographic (CT) scan revealed brain metastasis. His general condition degraded rapidly and he died of brain herniation 3 months after orchiectomy. Case 2; A 32-year-old male was admitted because of right testicular swelling and lung metastases (stage IIIB, pTiN0M1). Pathological examination revealed embryonal carcinoma, yolk sac tumor and teratoma. After 4 courses of chemotherapy with cisplatinum (CDDP), vincristine, methotrexate, peplomycin, and etoposide all lung metastases were disappeared. A few months later left hemiplegia by brain metastasis appeared suddenly. Four additional courses of high dose chemotherapy and resection of brain metastasis was performed. Complete remission continued for 13 months. The prognosis of testicular tumor with brain metastasis was very poor. During the last 8 years, 21 cases of testicular tumor with brain metastasis were reported in the Japanese literature. A follow-up study of prognosis in the literature was performed and discussed.

Adult↗

PubMed1993

Electron transfer process in milk xanthine dehydrogenase as studied by pulse radiolysis.

The reduction of milk xanthine dehydrogenase by salicylate anion radical (SL-), nicotinamide adenine dinucleotide radical (NAD.), and 1-methylnicotinamide (NMA) radicals was investigated by the use of pulse radiolysis. Reduction of the dehydrogenase with SL- proceeded via two phases. From the kinetic difference spectra obtained, the faster and slower phases of reduction represent that of one of the iron-sulfur centers and of FAD, respectively. The rate constant of the faster phase increased with the concentration of the enzyme, suggesting that the reduction follows a bimolecular reaction of SL- with the iron-sulfur center. In contrast, the rate constant of the slower phase (510 s-1) was independent of the concentration of the enzyme at pH 7.5. In order to elucidate the contribution of the molybdenum site in the reaction, a similar reaction was performed with enzyme modified with oxipurinol. In the modified enzyme, the slower phase was lost, whereas the faster phase was not affected. These results suggest that the slower phase is due to intramolecular electron transfer from the molybdenum center to FAD. On the other hand, NAD. reacted predominantly with FAD of the dehydrogenase to form the neutral semiquinone of FAD with a second order rate constant of 1.4 x 10(7) M-1 s-1 at pH 7.5, whereas a similar reaction in the oxidase, which was converted from xanthine dehydrogenase by proteolytical cleavage, was not observed. This suggests that NAD. transfers an electron via the binding site for NAD+ on the dehydrogenase. In contrast, NMA radical reduced only an iron-sulfur center of the dehydrogenase with a second order rate constant of 6.5 x 10(7) M-1 s-1 at pH 7.5.

Animals↗

PubMed1993

Kinetics of structural changes of reconstituted skeletal muscle thin filaments observed by fluorescence resonance energy transfer.

Fluorescence resonance energy transfer was measured between probes attached to Troponin-I and actin in the reconstituted skeletal muscle thin filament. Cys-133 on TnI was labeled with 4-acetamido-4'-maleimidylstilbene-2,2'-disulfonic acid, and Lys-61 on actin was labeled with fluorescein 5-isothiocyanate. A large difference in the efficiency of resonance energy transfer was observed between the presence (0.55) and absence (0.76) of Ca2+, which corresponds to the change in the distance of 0.53 nm and is in good accordance with a previous report (Miki, M. (1990) Eur. J. Biochem. 187, 155-162). The fluorescence titration curve of this reconstituted thin filament was measured versus free Ca2+ concentration under physiological conditions in the presence of 8 mM MgCl2. The transfer efficiency changed sharply between pCa 6.9 and 5.75, with a midpoint at pCa 6.25, suggesting that a conformational change of thin filaments occurs with a highly cooperative mode. The time course of this conformational change was followed by measuring the fluorescence intensity change (energy transfer efficiency change) of the labeled reconstituted thin filament after rapid decrease or increase of free Ca2+ concentration with a stopped-flow fluorometer. When the free Ca2+ concentration was increased in the presence of 5 mM MgCl2, the fluorescence intensity increased (the transfer efficiency decreased) with a rate constant of 530 +/- 170 s-1 at 20 degrees C. On the other hand, when the free Ca2+ concentration was decreased, the fluorescence intensity decreased with a rate constant of 43 +/- 5 s-1. The results indicate that the conformational change observed by fluorescence resonance energy transfer corresponds well to the regulation mechanism by troponin-tropomyosin on the reconstituted skeletal muscle thin filament.

Actins↗

PubMed1993

Doppler color flow imaging in the detection and quantitative measurement of the gastroduodenal artery blood flow.

The purpose of this article was to investigate the detection rate of gastroduodenal artery blood flow (GDABF), and to measure its velocity and volume flow rate using Doppler color imaging. The GDABF was detected in 40 of 41 (98%) normal subjects with longitudinal scanning and in 36 (88%) with transverse scanning. The velocity of the GDABF was 21 +/- 8 cm/sec (m +/- SD) and the volume flow rate was 67 +/- 20 mL/min. Without color Doppler, the vascular lumina of the GDA was demonstrated in 27 (66%) subjects by longitudinal scanning and in 26 (63%) by transverse scanning. The hemodynamics of the GDA were revealed noninvasively using Doppler ultrasonography in a patient with a malignant islet cell tumor of the pancreas and one with a ductal cell carcinoma of the pancreas.

Adenocarcinoma↗

PubMed1993

[Outpatient ESWL in 500 kidneys].

Between March 1989 and January 1992, 600 cases (636 kidneys) with upper urinary tract stones were treated with ESWL, using a Lithostar. Of these, 78.6% were carried out in our outpatient service, and in the last two years approximately 90% of cases have been treated as outpatient. We evaluated first 500 kidneys, treated with ESWL as outpatient. There were 481 cases involving 500 kidneys (19 bilateral cases). The ages of the 367 men and 114 women ranged from 16 to 77 years. There were 227 kidney stones and 273 ureter stones. Most of the stones were less than 20 mm. The average number of sessions and shock waves for each patient were 1.4 times and 6,988 waves, respectively. While 74% of the patients could be treated in only one session, 9% of them needed 3 sessions or more. Auxiliary measures were needed in 23 cases (D-J stent insertion in 5 cases and ureteral catheterization in 18 cases) and 474 cases (94.8%) were treated by in-situ procedures. At 3 months after treatment, 470 cases were evaluated and the stone-free rates of kidney stones and ureter stones were 70.3% and 84.5%, respectively with an overall stone-free rate of 78.1%. With regard to complications, the rate of the clinic visit because of pain after treatment was observed in 4.6% and higher than 38 degrees C in 2.5%. However, no serious perioperative complications occurred. From these results, outpatient ESWL was considered to be safe and efficient without serious complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

[Comparative assessment of the characteristics in various assay kits for prostate specific antigen].

Six kinds of assay kits based on different detecting principle for PSA were evaluated. Polyclonal antibody was used in 2 kits (Eiken, Markit-F) and monoclonal antibody in 4 kits (Ball Elsa, Delfia, Markit-M, Tandem-R). To evaluate their characteristics, sera of 12 female patients, 5 prostatectomized patients and 2 high stage prostate cancer patients were measured by these kits. On the female sera the polyclonal assay kits yielded values higher than the defined minimal sensitive value, but the kits of monoclonal antibody detected nothing. Dilution test of sera with high PSA level showed satisfactory results in every kit but the values of 6 assays were different to each other. For monitoring the recurrence or recrudescence of the prostatic cancer, the monoclonal antibody kits may be preferable to the polyclonal antibody kits. These results showed that we must understand the characteristics of every assay kit which is used clinically.

Adult↗

PubMed1993

[New microwave transurethral hyperthermia for benign prostatic hyperplasia--clinical evaluation].

Several types of hyperthermic apparatuses are employed to treat benign prostatic hyperplasia (BPH). As the prostate surrounds the urethra, we believed that transurethral heating allowed for more efficient and uniform heating. A new effective apparatus for this objective was developed. The size of our hyperthermic apparatus was about 52 x 45 x 20 centimeters and the originating frequency was 2,450 +/- 30 MHz. We used T-type thermocouples as temperature sensors. The transurethral applicator had a cooling system. Thirty patients complaining of obstructive symptoms due to BPH were treated. Hyperthermia was performed 3-6 times for each patients (two times per week). Each procedure was performed for 60 minutes. The temperature was controlled at 39 degrees C on the urethral surface (43 degrees C at prostate). The overall efficacy of this treatment was effective in 23 of the 30 patients (76.7%). In addition, there were no severe complications. As the size of this apparatus was miniaturized, it could be used at the bed side.

Aged↗

PubMed1993

[A case uterine cervical squamous cell carcinoma successfully treated with preoperative carboplatin-based 5-drug-combined intraarterial infusion chemotherapy].

Preoperative 5-drug-combined intraarterial infusion chemotherapy using carboplatin as a main component was performed in a case of uterine cervical squamous cell carcinoma of Stage IIa. The regimen employed was as follows: carboplatin (100 mg/m2) on Day 4 and 5, vincristine (0.6 mg/m2) on Day 1, peplomycin (5 mg/body) on Day 1, 2, and 3, methotrexate (5 mg/m2) on Day 2 and 3, and doxorubicin (15 mg/m2) on Day 4. These drugs were administered into the right inguinal region through a residual catheter at 3-week intervals prior to operation. After completion of 3 courses, the patient achieved a CR confirmed by pathological analysis and diagnostic imaging followed by extended radical hysterectomy. Side effects observed, especially renal disturbance and myelosuppression, were all tolerable. Intraarterial infusion chemotherapy using carboplatin was thus suggested to be useful against malignant tumors in the gynecological field.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1993

[A case of testicular tumor with liver metastases maintaining complete remission for a long period].

A 20-year-old man was admitted with multiple lung, liver and retroperitoneal lymph node metastases from right testicular tumor. The serum hCG level was 170,000 mIu/ml. Orchiectomized right testis showed choriocarcinoma and teratoma pathologically. After 3 courses of chemotherapy of cisplatin, vinblastine and bleomycin, retroperitoneal lymph nodes were resected. Three courses of salvage chemotherapy of VP-16 (etoposide) were performed. The serum hCG level became normal and all metastases disappeared. For 37 months after operation there has been no recurrence of tumor. The 29 cases of testicular tumor with liver metastasis reported in the Japanese literatures during the last 7 years were discussed. The prognosis of testicular tumor with liver metastasis is very poor. However, adequate combination therapy might be effective for the far-advanced testicular tumor.

Adult↗

PubMed1993

[Acute renal failure following mannitol infusion].

Mannitol is an osmotic diuretic used in acute oliguric renal failure, acute cerebral edema, and acute glaucoma. It is metabolically inert and is excreted through the kidneys. So once renal function is impaired, mannitol accumulates and the movement of water into the intravascular space with resultant cellular dehydration. Two patients suffered reversible acute oliguric renal failure following mannitol infusion given as treatment for intracranial hypertension. Both patients experienced nausea and vomiting and became increasingly lethargic with edema of general body. Congestive heart failure occurred. Laboratory data showed severe dilutional hyponatremia with hyperosmolality. We successfully treated them with extracorporeal ultrafiltration method (ECUM) and hemodialysis (HD). Some discussions were presented about acute renal failure following mannitol infusion.

Acute Kidney Injury↗

PubMed1993

[Recurrence presenting as anuria at 16 years after partial nephrectomy for a pelvic tumor in a solitary kidney: a case report].

A 61-year-old male underwent right partial nephrectomy for a pelvic tumor of a solitary kidney at the former hospital on April 1975. Two years later he had a small bladder tumor and transurethral resection was performed. Since August 1985 he had been followed up in our hospital. On June 1986, the urine cytology showed class V, but neither cystoscopy nor drip infusion pyelography revealed the tumor. On January 1992, he consulted our department with macrohematuria and anuria. Serum creatinine and blood urea nitrogen level were 17.24 mg/ml and 84.1 mg/ml, respectively. Hemodialysis was administered. Retrograde pyelography revealed a defect of tumor at the pyeloureteral junction, and pyuria by ureteral catheterization showed class V cytology. Abdominal CT showed right hydronephrosis caused by the recurrence of pelvic tumor, and right nephrectomy was performed. The histopathological diagnosis was non-papillary transitional cell carcinoma, grade 3 > 2, pT3. He is in good condition with maintenance hemodialysis. In the Japanese literature there were 16 cases of pelvic tumor on the solitary or residual kidneys. In 12 of the 16 cases, kidney sparing treatment was tried and only our case has lived over 10 years. The indication of partial nephrectomy for pelvis tumor was discussed.

Anuria↗

PubMed1992

The mechanism of inhibition of the actin-activated myosin MgATPase by calponin.

Calponin inhibits the actin-activated ATPase of smooth muscle myosin and thus has been proposed as a thin filament-based regulatory component in smooth muscle. To obtain information on the mechanism of inhibition by calponin we have used chemical modification of actin and cross-linking of actin and subfragment 1. Modification of Lys 61 of actin had no effect on the inhibition by calponin of acto-heavy meromyosin ATPase, i.e. different from tropomyosin-troponin. In addition, modification of the acidic N-terminal region of actin did not impair the ability of calponin to bind to F-actin. Finally, calponin was effective in inhibiting ATPase activity of cross-linked acto-subfragment 1. Therefore the mechanism of inhibition by calponin is distinct from troponin-tropomyosin and caldesmon in that it does not involve either the N-terminal acidic region of actin nor the area around Lys 61 and does not fit a simple steric blocking model.

Actins↗

PubMed1992

Malignant cell-specific gelatinase activity in human endometrial carcinoma.

BACKGROUND: The protease activity leading to degradation of the extracellular matrix was compared between human endometrial cancer and normal uterine endometrium. METHODS: Conditioned medium from tumor cells and normal endometrial cells was subjected to electrophoresis on sodium dodecyl sulfate (SDS)-polyacrylamide gel containing gelatin as a substrate. After electrophoresis, the gel was stained with Coomassie blue, and then the enzyme activity, expressed as the zone of dye clearing, was analyzed by densitometry. RESULTS: Densitometric analysis showed that all the endometrial cancers expressed a very high molecular weight enzyme activity (Mr 220,000), which was not detected in medium from normal endometrial cells. The analysis also showed that in endometrial cancer the activity of a Mr 92,000 enzyme was always superior to that of a Mr 64,000 enzyme, which was in contrast to the situation for normal endometrium. CONCLUSIONS: These results indicate that the expression of Mr 220,000 enzyme activity and the higher activity of the Mr 92,000 enzyme than the Mr 64,000 enzyme are involved in the malignant phenotype of native endometrial cancer.

Adenocarcinoma↗

PubMed1992

Removing the two C-terminal residues of actin affects the filament structure.

We define conditions under which the two C-terminal residues of actin, Cys-374 and Phe-375, can be selectively removed by proteolysis with trypsin. This modification had little effect on the secondary structure of actin detected by Fourier-transform infrared spectroscopy. However, removing these residues caused small but significant decreases in the critical concentration of actin, in its ability to activate myosin ATPase, and in its interaction with tropomyosin and troponin. Removing residues 374-375 caused dramatic changes in the actin filament as seen by electron microscopy. The filaments had a much greater and more irregular curvature and were intertwined into disordered multifilament bundles. Removing 374-375 also significantly lowered the flow viscosity of filamentous-actin solutions. These data suggest an increase in the flexibility and fragility of the filament, supporting the idea that the C-terminus forms one of the major intermonomer contacts in the filament.

Actin Cytoskeleton↗