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Biomedical subjects

Y Kikuchi

Publications and source records attributed to Y Kikuchi.

At least 181 records · Page 10Linked to original sources

Variants in the deep circumflex iliac artery: clinical considerations in raising iliac osteocutaneous free flaps.

Anomalies of the deep circumflex iliac artery do occur, although they are uncommon. Recently, two cases of these anomalies were encountered by the authors during elevation of iliac osteocutaneous free flaps. In the first case, the deep circumflex iliac artery was absent, and the nourishing artery of the flap was instead connected to the large iliolumbar artery. In the second case, the ascending branch, deriving from the deep circumflex iliac artery as usual, had a separate takeoff directly from the external iliac artery, and provided blood supply to the overlying skin as a musculocutaneous perforator that transversed the three muscle layers of the abdominal wall. This ascending branch was assumed to be a duplication of the deep circumflex iliac artery. Ascertaining the divergence of the deep circumflex iliac artery from the external iliac artery before beginning to raise the flap, and careful dissection of the artery, are essential for minimizing problems in flap transfer.

Bone Transplantation↗

Specific RNA protease inhibitors from in vitro selection.

RNA aptamers that bind to and inhibit the proteolytic activity of subtilisin BPN' are selected in vitro from pools of random RNA. The RNAs in vitro transcribed from the isolated clones show highly specific inhibition toward the microbial serine proteases. From the sequences of the isolated clones, a C/A-rich sequence was obtained. The kinetic features of the common C/A-rich sequence will be discussed.

Cloning, Molecular↗

Comparative study of two ribozymes and DNA-enzyme against the same RNA target.

Two ribozymes, hammerhead ribozyme and hairpin ribozyme, and a DNA-enzyme were designed to cleave a same RNA target, the same site of the rat complement regulatory factor 512 antigen mRNA. The kinetic properties of these RNA-cleaving enzymes were measured and compared under the same conditions, using multiple turnover kinetics and competition kinetics. The catalytic efficiencies of these enzymes, and also the order of these enzymes will be discussed.

Animals↗

Drosophila tRNAs hyperprocessed in vitro by ribonuclease P.

In transposon copia-related retrovirus-like particles of Drosophila, a 5' half fragment produced by the cleavage of mature initiator methionine tRNA is used as the primer for minus-strand reverse transcription. This cleavage is called hyperprocessing. We have previously reported that the catalytic RNA subunit of RNase P catalyzes this hyperprocessing in vitro and that this cleavage is dependent on the occurrence of an altered conformation of the tRNA substrate. Here, we found that other mature tRNAs of Drosophila were also hyperprocessed by M1 RNA in vitro and that some of such tRNAs were probably alanine and histidine tRNAs. Here we report these two tRNAs can also adopt their alternative conformations very similar to that of initiator methionine tRNA.

Animals↗

Selection of an RNA molecule that specifically inhibits the protease activity of subtilisin.

RNA ligands (RNA aptamers) to a protease subtilisin were selected from pools of random RNA by SELEX (systematic evolution of ligands by exponential enrichment) and by use of a subtilisin-immobilized Sepharose column. After eight rounds of selection, RNA aptamers were isolated by cloning to a plasmid vector. We characterized one of the selected RNA molecules. This RNA aptamer displayed specific inhibition toward the subtilisin activity, even when the assay for subtilisin was performed using the chromogenic small peptide as substrate, and almost no inhibitory activity toward trypsin and chymotrypsin, although these enzymes are serine proteases similar to subtilisin. These findings indicate that this RNA can differentially recognize the surfaces of similar proteases. Kinetic analysis of the RNA aptamer revealed that the inhibition constant (Ki) toward subtilisin was 2.5 microM.

Animals↗

Effect of temporary hepatic venous occlusion on hepatic arterial embolization. An experimental study.

RATIONALE AND OBJECTIVES: The authors evaluated the effect of hepatic venous occlusion on hepatic arterial embolization in rats. METHODS: A Lipiodol-Iopamidol mixture was injected into the proper hepatic artery in rats during clamping the right side of the hepatic venous confluence. The distribution of Lipiodol-Iopamidol mixture in the sinusoids was analyzed by histological examination with en bloc silver impregnation. The extent of the distribution of Lipiodol-Iopamidol mixture was compared in sinusoids with hepatic venous occlusion and in sinusoids without hepatic venous occlusion. RESULTS: Lipiodol-Iopamidol mixture was more widely distributed in the lobules with hepatic venous occlusion than in the lobules without occlusion. CONCLUSIONS: Hepatic venous occlusion may enhance the effect of hepatic arterial embolization using Lipiodol emulsions and could be useful in the treatment of hepatocellular carcinoma.

Animals↗

Hemodynamic effect of rapid atrial pacing in fetal lambs.

To determine the threshold at which rapid atrial pacing brings on fetal circulatory failure, we made a fetal supraventricular tachyarrhythmia model and measured the central venous pressure, aortic pressure, and right and left ventricular outputs in five fetal lambs. Under maternal anesthesia, the uterus was opened, and under local anesthesia, polyvinyl catheters were inserted into the fetal superior vena cava and ascending aorta through a neck incision. Pacing leads (Medtronic model 6492) were then sutured onto the fetal right atrial appendage via right thoracotomy. Ventricular output was estimated using a Toshiba SSH-65A echocardiography by a transuterine approach. Fetal hemodynamics were observed without pacing (control), and at the atrial pacing rates of 200, 300, 350, and 400/min. Central venous pressure (CVP) increased and the aortic pressure decreased when the right atrium was paced at 350/min or more. Right ventricular output decreased when the right atrium was paced at 300/min or more. The left ventricular output, however, remained constant. The right ventricular output was 382 +/- 106 mL/kg/min at control, and 391 +/- 117 mL/kg/min when paced at 200/min, but decreased to 210 +/- 138 mL/kg/min when paced at 300/min, to 223 +/- 102 mL/kg/min when paced at 350/min, and to 186 +/- 86 mL/kg/min when paced at 400/min. Fetal circulatory failure occurred when the right atrium was paced at 300/min or more.

Animals↗

Preoperative determination of several serum tumor markers in patients with primary epithelial ovarian carcinoma.

This study was designed to evaluate the clinical significance of the use of preoperative serum tumor markers in primary epithelial ovarian cancer. Subjects comprised 111 patients with primary epithelial ovarian cancer. Lactate dehydrogenase (LDH), alpha-hydroxybutyrate dehydrogenase (HBDH), carcinoembryonic antigen (CEA), CA19-9, tissue polypeptide antigen (TPA), CA125 and sialyl TN (STN) serum levels were measured within 7 days before surgery. The tumor marker values were compared with the histopathologic diagnosis. The overall agreement between the test results and the actual outcome was calculated using Student's t test and analysis of variance (ANOVA). Survival curves were constructed according to the Kaplan-Meier method, and differences in survival were assessed with the log-rank test. The prognostic significance of tumor markers for survival was assessed in a multivariate analysis with the Cox proportional hazards model. Of the tumor markers examined in this study, CA125 showed the highest positive rate (77.6%), followed by 63.2% for STN and 55.9% for CA19-9. When the positive rate was compared according to histologic types, serous cystadenocarcinoma, mucinous cystadenocarcinoma, endometrioid adenocarcinoma and clear cell carcinoma showed the highest positive rates for CA125 (94.1%), CA19-9 (76.9%), CA125 (91.7%) and STN (75.0%), respectively. Regarding the distribution of tumor marker levels according to the FIGO stage, LDH, HBDH, TPA and CA125 were correlated with the clinical stage while CEA, CA19-9 and STN did not show any correlation. From analyses of tumor marker levels according to histologic types, all patients with a ratio of CA125 to CEA of >1, 000 had serous cystadenocarcinoma and a ratio of CA125 to CA19-9 of >50 showed serous cystadenocarcinoma or endometrioid adenocarcinoma. On the other hand, all patients with a ratio of LDH or HBDH to CA19-9 of <1.0 had mucinous cystadenocarcinoma or clear cell carcinoma. From univariate analysis, the survival time of patients with elevated CA125, TPA or STN was significantly shorter than that of patients with normal CA125, TPA or STN levels. When the Cox's proportional hazard model was used, we identified age, clinical stage, clear cell carcinoma and serum STN as independent prognostic factors. Serum CA125, TPA or STN may give significant prognostic information in epithelial ovarian carcinoma. It is noteworthy that STN has been identified as an independent prognostic factor and has a high rate of positivity in clear cell carcinoma.

Adenocarcinoma↗

Effects of oral supplementation with evening primrose oil for six weeks on plasma essential fatty acids and uremic skin symptoms in hemodialysis patients.

Abnormalities in plasma composition of essential fatty acids (EFAs) may be associated with the etiology of pruritus and other skin problems in patients undergoing hemodialysis. To study whether an oral supplementation with omega-6 (n-6) EFAs would restore deranged plasma EFAs and ameliorate skin symptoms, 9 and 7 dialysis patients were randomly assigned to receive either gamma-linolenic acid (GLA)-rich evening primrose oil (EPO) or linoleic acid (LA) (2 g/day each) for 6 weeks. Plasma concentrations of EFA were analyzed by gas chromatography and uremic skin symptoms were assessed for dryness, pruritus and erythema by questionnaire and visual inspection in a double-blind manner. The patients given EPO exhibited a significant (p < 0.05) increase in plasma dihomo-gamma-linolenic acid (a precursor of anti-inflammatory prostaglandin E1) with no concomitant change in plasma arachidonic acid (a precursor of pro-inflammatory prostaglandin E2 and leukotriene B4). In contrast, those given LA exhibited a significant (p < 0.05) increase in LA but not in any other n-6 EFAs, whereas they exhibited a significant (p < 0.05) decrease in plasma docosahexaenoic acid. The patients given EPO showed a significant (p < 0.05) improvement in the skin scores for the three different uremic skin symptoms over the baseline values and a trend toward a greater improvement (0.05 < p < 0.1) in pruritus scores than those given LA. Results indicate that GLA-rich EPO would be a more favorable supplemental source than LA in terms of shifting eicosanoid metabolism toward a less inflammation status through modifying plasma concentrations of their precursor n-6 EFAs. Further studies are required to confirm the efficacy and safety of EPO therapy for the treatment of uremic pruritus.

Administration, Oral↗

Nocturnal blood pressure during apnoeic and ventilatory periods in patients with obstructive sleep apnoea.

The exact nature of asleep blood pressure in relation to awake blood pressure is still unclear in patients with obstructive sleep apnoea. This study aimed: 1) to investigate the asleep blood pressure in both apnoeic and ventilatory periods; 2) to determine the diurnal and nocturnal factors correlated with the changes in blood pressure from apnoea to ventilatory periods during sleep. Thirty-two patients, newly diagnosed as moderate to severe obstructive sleep apnoea with a standard nocturnal polysomnography, were enrolled. The blood pressure was monitored by using the noninvasive continuous monitoring method during polysomnographic study. The mean blood pressures in ventilatory periods during nonrapid eye movement (NREM) and rapid eye movement (REM) sleep were 117.5+/-17.9 mm Hg and 128.8+/-21.9 mm Hg, and those in apnoea periods were 94.5+/-15.4 mm Hg and 102.7+/-19.0 mm Hg. The average blood pressure during NREM sleep (103.0+/-16.1 mm Hg) was higher than the awake blood pressure (97.0+/-15.7 mm Hg). The blood pressure during REM sleep was greater than that during NREM sleep. The changes in the nocturnal blood pressure from apnoea to ventilatory periods were inversely correlated with the age and nocturnal mean nadir saturation. In conclusion, patients with obstructive sleep apnoea have higher asleep blood pressure than awake blood pressure.

Adult↗

A mild transient decrease of peripheral red blood cell counts induced by a suprapharmacological dose of pegylated human megakaryocyte growth and development factor in rats.

Previous studies have shown that pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) at suprapharmacological dose induces a mild transient decrease of red blood cell counts according to thrombopoiesis in normal mice. To unravel the mechanism underlying this mild transient decrease of red blood cells, we have studied the effect of PEG-rHuMGDF on the circulating plasma and blood volume, and the serum biochemical parameters of anaemia and splenectomy. Also, we have performed histological studies of the bone marrow and the spleen of PEG-rHuMGDF-treated rats. PEG-rHuMGDF (300 microg kg(-1)]) or vehicle was subcutaneously administered to rats once a day for up to five days. From day 6 after the start of PEG-rHuMGDF administration, the platelet counts and plateletcrit levels were significantly increased, reaching peak values on day 10, and recovering to normal by day 20. The red blood cell counts and the haematocrit levels were significantly decreased on day 6 to 13. The decreases in red blood cell levels and haematocrit produced by PEG-rHuMGDF treatment were mild and had recovered by day 15. The plasma and blood volumes were significantly increased on day 10 in PEG-rHuMGDF-treated rats. No alteration of the serum biochemical parameters for anaemia, iron or total bilirubin, were observed on day 10. The histological examination on day 10 revealed a marked increase in megakaryocytes and a slight decrease in erythropoiesis in the bone marrow of rats that received PEG-rHuMGDF (300 microg kg(-1)). There was also a slight increase in splenic megakaryocytes and erythropoiesis. The decrease of red blood cells by PEG-rHuMGDF was not affected by splenectomy. These results suggest that the mild transient decrease of red blood cells induced by PEG-rHuMGDF treatment for up to five days is based mainly on the increases in the plasma and blood volume. These events are secondary changes due to the regulation of the excess production of megakaryocytes in the marrow and the peripheral platelets.

Anemia↗

Functional prognosis after treatment of spinal dural arteriovenous fistulas.

Functional prognosis after treatment for spinal dural arteriovenous fistulas (SDAVFs) was retrospectively analyzed in 13 consecutive patients aged 38 to 73 years (mean 57 years) treated during the last 5 years. The duration of symptoms before diagnosis ranged from 3 to 72 months (mean 23 months). Neurological symptoms were examined before and 6 months after the treatment. Seven patients underwent embolization as the initial treatment. In four of six patients, N-butyl 2-cyanoacrylate (NBCA) embolization achieved complete obliteration of SDAVF. The other two patients with incomplete embolization and one embolized with polyvinyl alcohol particles underwent subsequent surgical treatment. Six patients were treated by direct surgery. Complete disappearance of SDAVF was confirmed in all nine patients treated surgically. Improvement of gait and micturition disturbance after the treatment was noted in six of 10 and three of six patients, respectively. Long duration of symptoms and high grade of neurological symptoms were associated with a poor functional outcome. NBCA embolization and surgery are curative treatments for SDAVF, but the functional prognosis is not always satisfactory. Embolization is the first choice of treatment for SDAVF because it is less invasive and relatively safe. However, when complete obliteration is not achieved, prompt surgery is recommended because a long duration of symptoms will result in a poor functional prognosis.

Adult↗

Aggravation of brainstem symptoms caused by a large superior cerebellar artery aneurysm after embolization by Guglielmi detachable coils--case report.

An 81-year-old male presented with right oculomotor nerve paresis and left hemiparesis caused by a mass effect of a large superior cerebellar artery aneurysm. Endovascular treatment was performed using Guglielmi detachable coils. The patient subsequently suffered aggravation of the mass effect 3 weeks after the embolization. Bilateral vertebral artery occlusion was performed, which decreased the cerebral edema surrounding the aneurysm, but his neurological symptoms did not improve. Parent artery occlusion is recommended as the first choice of treatment for an unclippable large or giant aneurysm causing a mass effect on the brainstem.

Aged↗

Health consciousness of young people in relation to their personality.

Personality of targeted individuals can be assumed to influence behavior modification by health education. In this study the influence of personality on health consciousness was analyzed by a questionnaire for lifestyle, health consciousness, and the NEO-FFI personality test. Subjects were 942 new students in the Tokyo University of Agriculture who were surveyed in April, 1998. Separately performed health examination data were used to verify reliability of answers to the questionnaire. Among students, 83.2% of males and 90.4% of females felt themselves to be healthy, and more than 80% students desired to improve their health more. The rate of having no physical complaints, however, was only 31.7% in males and 20.4% in females. Distribution of NEO-FFI scores of neuroticism (N), extraversion (E), openness (O), agreeableness (A), and conscientiousness (C) corresponded well between males and females, except for significantly higher scores of O and A in females. Odds ratios (ORs) between high and low tertial points of NEO-FFI score for health consciousness were significantly elevated in the high scoring groups of E and C (OR = 6.26, 95% CI = 1.46-26.82, and OR = 6.04, 95% CI = 1.42-25.71, respectively) in males. On the contrary, high N and O groups had low health consciousness. Smoking habit was associated with high E scores (OR = 2.24, 95% CI = 1.13-4.43). Dietary habits, regular eating time, and avoidance of salty foods were associated with high C scores in both males and females. The OR of regular eating time was 2.66 (95% CI = 1.42-1.98), and 2.20 (95% CI = 1.31-3.71) for males and females, respectively. The OR of avoidance of salty foods were 2.09 (95% CI = 1.11-3.91), 1.87 (95% CI = 1.11-3.16) for males and females, respectively. Significant associations between lifestyle and personality require further study for risk association analysis and for relationship to interventive practices for prevention of lifestyle associated diseases.

Adolescent↗

Ruptured distal aortic arch aneurysm associated with arteriosclerosis obliterans.

A 73-year-old man with a ruptured distal aortic arch aneurysm into the pericardial space, mediastinum and right pleural space is described. The patient underwent a successful total aortic arch replacement using deep hypothermia, systemic circulatory arrest and selective cerebral perfusion. Extracorporeal circulation was established with right axillar arterial perfusion due to arteriosclerosis obliterans (ASO). Presentation and management are discussed.

Aged↗

Multiple dural arteriovenous shunts in a 5-year-old boy.

We describe a rare case of multiple dural arteriovenous shunts (DAVSs) in a 5-year-old boy. MR imaging performed at 1 year of age showed only a dilated anterior part of the superior sagittal sinus; however, angiography at 5 years of age revealed an infantile-type DAVS there and two other DAVSs of the adult type. The pathophysiological evolution of DAVSs in children and their treatment strategies are discussed.

Angiography↗