Search PubMed⌕ Search

Biomedical subjects

H Aoki

Publications and source records attributed to H Aoki.

At least 217 records · Page 12Linked to original sources
PubMed1995

Surgical treatment of renal cell carcinoma extending into the vena cava.

BACKGROUND: Renal cell carcinoma has a tendency to invade the vasculature and the prognostic implications of intravena caval tumor thrombectomy remains controversial. We reviewed our clinical experience with RCC patients who underwent tumor thrombectomy and radical nephrectomy. METHODS: Surgery was carried out in 13 renal cell carcinoma patients with inferior vena cava extension over the past seven years. Diagnosis of intracaval tumor extension and thrombus formation was made by imaging techniques including ultrasonography and computed tomography. Cavography and magnetic resonance imaging were also performed in some cases. RESULTS: The level of the tumor thrombus was infrahepatic (V2a) in nine cases and retrohepatic (V2b) in four. Ultrasound and magnetic resonance imaging were extremely useful in defining the extent of the thrombus in addition to detecting its presence. The caval thrombi were reached simply by ligation and division of the short hepatic veins in the V2a cases, but liver mobilization was required in the V2b cases. There were no operative deaths. Two patients who had metastases on surgery died of the disease eight and 13 months after surgery. Four of the 11 patients in whom no evidence of metastasis was found on surgery also died of the disease between nine and 16 months postoperatively. The remaining seven patients are still alive at periods of 6-74 months after surgery, with or without residual tumors. The nature of the intracaval tumor thrombi seems to affect the overall prognosis for survival. Elevated levels of acute phase reactants and immunosuppressive acidic protein were associated with short survival times. CONCLUSIONS: Our experience suggests that aggressive surgery should be considered in selected patients with non-metastatic renal cell carcinoma extending into the vena cava.

Aged↗
PubMed1995

Mechanism of endothelium-dependent relaxation induced by substance P in the coronary artery of the pig.

1. Using front-surface fluorometry of fura-2-loaded porcine coronary arterial strips with the endothelium intact, we investigated the mechanisms of vasorelaxation induced by substance P (SP). Fura-2 fluorescence signals which indicated the cytosolic Ca2+-concentration ([Ca2+]i), were observed to arise exclusively from teh smooth muscle cells in these strips. 2. During the contractions induced by U46619 (100 nM), a thromboxane A2 analogue, an SP-induced endothelium-dependent, biphasic vasorelaxation was observed, which consisted of an initial rapid relaxation phase followed by a sustained phase, with a transient decrease in [Ca2+]i. Pretreatment with indomethacin (Ind) had no effect on the SP-induced relaxation; however, pretreatment with NG-nitro-L-arginine (L-NOARG) partially, but significantly inhibited the decrease in both the [Ca2+]i and tension abolished. Thus, part of the relaxation was considered to be mediated by L-NOARG-sensitive relaxing factor (endothelium-derived relaxing factor: EDRF). 3. During the 40 mM K+-depolarization-induced contraction which may eliminate the effects of endothelium-derived hyperpolarizing factor (EDRF), the vasorelaxation reduced by SP was completely inhibited by L-NOARG. 4. During the vasorelaxation induced SP, the [Ca2+]i-tension relationships shifted to the right of the contractions induced by either U46619 or high K+-depolarization. 5. Using front-surface fluorometry of fura-2 loaded porcine aortic valvular strips, we examined the effects of SP on [Ca2+]i in endothelial cells in situ. SP induced a rapid increase in [Ca2+]i of endothelial cells in situ followed by a small sustained phase in normal PSS (5.9 mM K+). The increase in extracellular K+ had no apparent effect on the SP-induced [Ca2+]i elevation of endothelial cells.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1995

Evidence for the presence of endothelin ETA receptors in endothelial cells in situ on the aortic side of porcine aortic valve.

1. In the present study, we determined whether ETA receptors are present on endothelial cells in situ, by use of front-surface fluorometry of fura-2-loaded porcine aortic valvular strips and reverse transcription polymerase chain reaction (RT-PCR). 2. Although endothelin-1 (ET-1) and endothelin-3 (ET-3) induced maximum elevations of cytosolic Ca2+ concentrations ([Ca2+]i) at 10(-7) M, the peak elevations of [Ca2+]i induced by ET-1 were much greater than those induced by ET-3. 3. The application of ET-1 after ET-3 induced an additional increase in [Ca2+]i, while the application of ET-3 after ET-1 had no effect. A selective ETA receptor antagonist, BQ-123, partially inhibited the ET-1-induced Ca2+ transient but had no effect on ET-3-induced Ca2+ transients. These experiments indicated the presence of functioning ETA receptors in addition to ETB receptors in endothelial cells in situ. 4. The sequence of pig lung ETA receptor complimentary DNA (cDNA) was determined by PCR. RT-PCR, using specific primers for pig ETA receptor sequence and total RNA from endothelial cells on the aortic side of the aortic valve, gave the expected size of band. This PCR product was sequenced and was found to be identical to the sequence of the pig lung ETA receptor. 5. The partial sequence of the pig lung ETB receptor was also determined. RT-PCR for the pig ETB receptor revealed that endothelial cells of the aortic valve express ETB receptor messenger RNA (mRNA). 6. We confirmed that functioning ETA receptors and expression of ETA receptor mRNA exist in the endothelial cells on the aortic side of porcine aortic valves.

Amino Acid Sequence↗
PubMed1995

Antiviral effect of oryzacystatin, a proteinase inhibitor in rice, against herpes simplex virus type 1 in vitro and in vivo.

Oryzacystatin (OC) is the first-described cystatin originating from rice seed; it consists of two molecular species, OC-I and OC-II, which have antiviral action against poliovirus in vitro (H. Kondo, S. Ijiri, K. Abe, H. Maeda, and S. Arai, FEBS Lett. 299:48-50, 1992). In the experiments reported here, we investigated the effects of OC-I and OC-II on the replication of herpes simplex virus type 1 (HSV-1) in vitro and in vivo. HSV-1 was inoculated onto monolayers of monkey kidney epithelial cells (CV-1 cells) at a multiplicity of infection of 0.1 PFU per cell. After adsorption of the virus onto cells, the cultures were incubated in the presence of either OC-I or OC-II in the concentration range of 1.0 to 300 microM, and the supernatant virus yield was quantitated at 24 h. The effective concentration for 90% inhibition of HSV-1 was 14.8 microM, while a cytotoxic effect on CV-1 cells without infection of HSV-1 was not observed below 500 microM OC-I. Therefore, the apparent in vitro chemotherapeutic index was estimated to be more than 33. In the mouse model of HSV-1-induced keratitis and encephalopathy, topical administration of OC-I to the mouse cornea produced a significant decrease in virus production in the cornea (mean virus yields: 3.11 log10 PFU in the treated group and 4.37 log10 PFU in the control group) and significant improvement in survival rates (P = 0.01). The in vivo antiherpetic effect of OC-I was comparable to that of acyclovir, indicating that topical treatment of HSV-1 infection in humans with OC-I might be possible. Our data also suggest the importance of some thiol proteinases, which may be derived from either the host's cells or HSV-1, during the replication process of HSV-1.

Animals↗
PubMed1995

Genomic instability involved in virus-related hepatocarcinogenesis.

In spite of the epidemiological link between the hepatitis C virus (HCV) infection and the incidence of hepatocellular carcinoma (HCC), there is currently no data to prove the direct oncogenicity of HCV. In this situation, we must consider not only the viral but also the nonviral factor which may accelerate hepatocarcinogenesis. Previously, we showed that a 60-bp subgenomic HBV DNA (15AB, nt 1555-1914 of HBV DNA) is a hot spot for the genomic recombination, and the cellular protein binding to 15AB may be the putative recombinogenic protein. In this paper, we show that the 15AB-like sequence exists in the human chromosomal DNA. The 15AB-binding proteins, candidates for the cellular recombinogenic protein, are now isolated and being characterized. We showed the possibility that, in HCV- as well as HBV-associated chronic active liver diseases, the recombinogenic proteins are expressed more abundantly than in the normal liver, and their functions are triggered by the binding to the recombinational hot spot in the chromosomal DNA.

Carcinoma, Hepatocellular↗
PubMed1995

Cloning and nucleotide sequence of a leaf ferredoxin-nitrite reductase cDNA of rice.

A ferredoxin-nitrite reductase (EC 1.7.7.1) cDNA was isolated and sequenced from a lambda gt 11 cDNA library constructed from nitrate-induced greening shoots of rice (Oryza sativa L.) seedlings. The nucleotide sequence of the cDNA clone contains an open reading frame of 1788 nucleotides. There exists a strong bias for the third codon usage of G/C (95.5%) as in the case of the maize enzyme. The deduced amino acid sequence shows an overall homology to the maize (81%) and the dicot enzymes (70-74%), suggesting that the primary structure of ferredoxin-nitrite reductase is highly conserved in higher plants.

Amino Acid Sequence↗
PubMed1995

Dynamic aspects in the expression of the goat insulin-like growth factor-I (IGF-I) gene: diversity in transcription and post-transcription.

Goat IGF-I (gIGF-I) cDNA was cloned using the reverse transcriptase-polymerase chain reaction (RT-PCR). The cDNA, which was homologous to rat class 1 IGF-I cDNA, was 969 bp long. From the open reading frame found in it, we predicted a 154 amino acid protein consisting of a 49 amino acid signal peptide, a 70 amino acid mature IGF-I peptide, and a 35 amino acid E domain (the COOH-terminal peptide). From the gIGF-I gene, we isolated and sequenced some segments containing four exons that encompassed the entire gIGF-I cDNA sequence. Goat liver RNA was analyzed by RT-PCR, and the nucleotides of the RT-PCR products were sequenced and checked with the nucleotide sequences of the segments from the gIGF-I gene. The gene had three leader exons (1W, 1, and 2, from upstream to downstream) and was transcribed into three kinds of mRNAs (classes 1W, 1, and 2). Another RNA species was detected by RT-PCR analysis of exon 1W. We sequenced it and found that in this transcript, the 3'-portion of exon 1 was inserted between exons 1W and 3, resulting in class 1W-1 del. mRNA. That is to say, the gIGF-I gene had three leader exons and four kinds of mature mRNA.

Amino Acid Sequence↗
PubMed1995

A study on the difference of human sensation evaluation to whole-body vibration in sitting and lying postures.

The evaluation of vibration sensation is a problem which has large individual differences. In order to clarify the relationship between posture and psychological response, human sensation to whole-body vibration (from 2 to 11 Hz) in sitting and lying postures was evaluated by the semantic differential method, and the influences of posture on the evaluation were investigated by using the fuzzy measure. Furthermore, the paired t-test was used to test the significant differences in the results of evaluation between the two postures. The results were as follows: (1) Psychological responses of human beings to whole-body vibration were greatly affected by the postures. (2) Changes of the psychological responses in the lying posture were smaller than those in the sitting posture. (3) There were significant differences between sitting and lying postures in the evaluation results of physiological factor, psychological factor and synthetic evaluation (P < 0.025).

Adaptation, Psychological↗
PubMed1995

CT evaluation of hepatic tumors: comparison of CT with arterial portography, CT with infusion hepatic arteriography, and simultaneous use of both techniques.

OBJECTIVE: We hypothesized that CT with arterial portography (CTAP) might depict tumors undetected by CT with infusion hepatic arteriography (CTIHA), and the converse. Accordingly, we compared the detection rate of malignant tumors using CTAP, CTIHA, and simultaneous use of both techniques to determine whether CTIHA can be used to distinguish malignant from benign hepatic nodules. SUBJECTS AND METHODS: Fifty-four candidates for partial liver resection who underwent combined CTAP and CTIHA were studied. Histopathologic study confirmed 77 malignant and 15 benign nodules in these patients. CTAP, CTIHA, and combined CTAP and CTIHA were used by three observers before surgery, and the sensitivities of the three methods in detecting malignant tumors were compared. Contrast-enhancement patterns of the nodules on CTIHA scans were determined. RESULTS: Sixty-eight malignant nodules (88%) were detected with CTAP, 64 (83%) with CTIHA, and 69 (90%) with simultaneous interpretation of both scans. These differences were not significant. CTIHA showed 16 malignant and 12 benign small nodules. Of these, 13 malignant and two benign nodules had rim enhancement. Use of rim enhancement as the criterion for malignancy of these small nodules gave an accuracy rate of 82%. CONCLUSION: CTAP, CTIHA, and simultaneous use of both techniques are similar in their ability to detect malignant hepatic tumors. CTAP alone is recommended for the detection of malignant hepatic tumors. CTIHA is of value in differentiating malignant from benign small nodules.

Adult↗
PubMed1995

[Long-term results of Bentall and modified Bentall procedure in aortic root replacement].

Between 1976 and 1994, sixteen patients who had annulo-aortic ectasia required aortic root replacements. Ten patients had annulo-aortic ectasia and 6 patients had aortic dissections. The operative techniques included Bentall procedure in 6, Cabrol procedure in 3 and Carrel patch procedure in 7. No hospital death was noted, although there were three major late complications and two of them died. First patient having Bentall procedure died from acute myocardial infarction because of the compressed left coronary artery by the wrapping aneurysmal wall. Second patient having Bentall procedure had enlargement of residual false lumen. Third patient having Cabrol procedure developed false aneurysm at the ostial anastomosis and died of cerebral haemorrhage. In contrast, no late complication has been noted in patients having Carrel patch procedure. Although further long-term follow-up is required, our experience suggests that Carrel patch procedure has less late complication.

Adult↗
PubMed1995

Hydroxyapatite coating on Ti plate by a dipping method.

Hydroxyapatite (HAP)-coated metal composites were made by the dipping method. The specimen substrates were Ti plates with a thickness of 2 mm. The HAP coating was carried out in HAP-sol for 1 min by the dipping method. The concentration of HAP-sol for the coating ranged from 3.28 to 9.99 wt%. Excellent coating was observed on Ti substrate dipped once in 9.99 wt% sol. A surface pretreated with a sandblasting provided a much better coating than a smooth surface. As the concentration of sol increased, the weight change and the coating thickness increased. Above 7 wt% sol, they increased sharply.

Biocompatible Materials↗
PubMed1995

Reaction of hydroxyapatite-sol in bone marrow.

Hydroxyapatite-sol was prepared by dispersing hydroxyapatite microcrystals into saline. The hydroxyapatite microcrystals were synthesized by neutralization reaction of calcium hydroxide suspension and phosphoric acid solution. Sizes of the hydroxyapatite microcrystals were less than 0.1 microns, and the mean value was 0.05 microm. The 0.2 ml hydroxyapatite-sol with a concentration of 14.8 mg/ml was injected into medullary cavities of rat femurs. Both sintered hydroxyapatite powder suspension and saline as comparative materials were injected into the medullary cavities in the same way. Reaction of the hydroxyapatite-sol in the bone medullary cavities was investigated histologically using light and transmission electron microscopes. After 3 days, new bone formation was observed by injection of hydroxyapatite-sol, while no bone formation was observed by injection of sintered hydroxyapatite powder and saline. Osteoblasts were observed endocytosing the hydroxyapatite-sol in the medullary cavities of the rats. Macrophages and undifferentiated osteoblasts were found around the hydroxyapatite-sol aggregation by transmission electron microscope. After 5 days, amounts of new bone increased and matured, forming trabeculae. Many osteoblasts were observed in a line along the surface of the bone. On the other hand, 5 days after injection of sintered hydroxyapatite powder and saline to bone formation was observed while at 10 days after injection, some immature new bone formation started to be observed. New bone increased and matured at 15 days postoperatively. From these results, it was concluded that hydroxyapatite-sol only quickly promotes the formation of new bone in bone marrow and can be used as injection liquid of new biomaterials for bone formation.

Animals↗
PubMed1995

[A huge idiopathic brain stone in the posterior fossa].

We report a case of idiopathic brain stone occurring in the posterior fossa. A 72-year-old woman with a huge calcified mass in the posterior fossa on plain craniogram was referred to us. She had suffered from intractable tinnitus and mild cerebellar ataxia for twenty years. CT scan revealed a dense bony mass in the posterior fossa. Angiogram only showed an avascular huge mass in the posterior fossa. MRI clearly revealed the shape, heterogenous composition and anatomical relation to the surrounding structure of the mass. The mass was totally removed uneventfully under ABR and SEP monitoring. The patient was discharged with improvement of subjective symptoms. The mass was histologically diagnosed as an idiopathic brain stone because its components were mainly calcified tissues and collagen fiber of unknown etiology; no viable cells were found in any of the specimens. Idiopathic brain stones are very rare and only eight cases have been reported in the literature. The etiology and clinical symptoms of this condition are briefly discussed.

Aged↗
PubMed1995

[Dural AVF of the posterior fossa associated with sinus occlusion presenting as intracerebral hemorrhage: case report].

A 69-year-old man was admitted because of sudden onset of consciousness disturbance. Neurological examination on admission revealed slightly disturbed consciousness, sensory aphasia and right hemiparesis. CT scan disclosed a hematoma in the left posterior temporal lobe. Left carotid angiograms showed dural AVF of the transverse/sigmoid sinus fed mainly by the left occipital and posterior auricular arteries. On the angiograms the left sigmoid sinus was completely occluded. This was associated with retrograde venous flow into the cortical veins, the superior petrosal sinus and the contralateral traverse sinus. After stabilizing the condition, we totally resected the dural AVF including the left transverse sinus. The postoperative course was uneventful. Histopathological examination of the surgically resected specimen revealed that the dural A-V fistula per se existed in the sinus wall.

Aged↗
PubMed1995

[Emergency coronary bypass grafting for failed percutaneous transluminal coronary angioplasty].

From January 1992 through September 1993, 545 patients underwent PTCA in Asahikawa City Hospital. 6 patients (1.1%) required emergency CABG. Perfusion catheter was placed in three patients. This catheter allowed for immediate and temporary reperfusion of blood to the ischemic myocardial tissue. And it provided us with time and a patient in stable condition. This technique reduce PMI, morbidity, and mortality in emergency CABG after failed PTCA.

Aged↗
PubMed1995

[A case of aortic bicuspid valvular endocarditis with congenital left ventricular diverticulum].

A 29-year-old man had a prolonged fever and painful Osler's nodes on his right foot. The aortic valve was bicuspid with vegetation mass and the left ventricular diverticulum was additionally present connecting with the left ventricular outflow tract. An operation was performed after intravenous administration of antibiotics for 3 weeks. The aortic bicuspid valve and the vegetation were removed and replaced by an artificial valve (SJM-HP 19 mm). The left ventricular diverticulum was resected. The echocardiographic findings correlated well with the intraoperative observation.

Adult↗