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Biomedical subjects

T Okamura

Publications and source records attributed to T Okamura.

At least 343 records · Page 19Linked to original sources
PubMed1995

[Transrectal portal scintigraphy for evaluation of portal hemodynamics before and after TIPS].

In order to evaluate portal venous hemodynamics before and after TIPS, transrectal portal scintigraphy was performed in 8 patients. In all 8 patients, scintigram before TIPS demonstrated hepatofugal flow in the portal vein and less accumulation of radioisotope in the liver. In the scintigrams for follow-up of TIPS, the flow direction in the portal vein changed to be hepatopedal. In 3 of the patients in whom stent shunt was occluded after TIPS, the portal blood flow was turned to be hepatofugal again. It is concluded that transrectal portal scintigraphic studies of the TIPS patients provide noninvasive evaluation of portal hemodynamics.

Aged↗
PubMed1995

[A case of ruptured cerebral aneurysm associated with fenestrated vertebral artery in osteogenesis imperfecta].

An extremely rare case of ruptured cerebral aneurysm associated with a fenestrated vertebral artery in osteogenesis imperfecta (OI) is presented. A 33-year-old female suffering from OI was admitted to our hospital with severe headache and vomiting. A CT scan revealed subarachnoid hemorrhage. Cerebral angiography with four vessel study showed a fenestration in the V3 portion of the left vertebral artery and a dilatation in its V4 portion, but no cerebral aneurysm was detected. After conservative treatment for three weeks, repeated angiography demonstrated an aneurysm of the anterior communicating artery. A neck clipping of the aneurysm was performed successfully. The patient was discharged with no neurological deficits. OI is a hereditary connective tissue disease characterized by bone fragility. From her family history and clinical findings, the patient was suspected to have OI type I of Sillence's classification. Among the connective tissue diseases, OI does not have complications in the cerebrovascular system as frequently as other connective tissue diseases do, for example, Marfan's syndrome, Ehlers-Danlos syndrome, or pseudoxanthoma elasticum. Carotid-cavernous fistula and moyamoya disease have been the only complications reported in OI. However, dilatation of the aortic root and increased vascular fragility have been reported recently in OI. Although this is the first reported case of a ruptured aneurysm accompanied by a fenestration and a dilatation of the vertebral artery associated with OI, it was suggested that vascular fragility caused by collagen abnormality might affect the cerebral vasculature.

Adult↗
PubMed1995

Evaluation of effects of chitosan in preventing hemorrhagic cystitis in rats induced by cyclophosphamide.

Hemorrhagic cystitis is a common problem following cyclophosphamide or radiation therapy. Chitosan has been shown to be an effective hemostatic agent and promoter of wound healing in animal experiments. We evaluated the safety and efficacy of intravesical chitosan in an animal model of cyclophosphamide cystitis. Hemorrhagic cystitis was induced in female F344 rats by intraperitoneal cyclophosphamide, 100 mg/kg. Chitosan solution (0.3 ml) was instilled intravesically on day 1 (Group 1), on days 1, 3, and 5 (Group 2), or 1 hour after the administration of cyclophosphamide (Group 3). The rats in group 4 were treated with chitosan diluent on day 1 after cyclophosphamide, and the rats in group 5 received intravesical chitosan without cyclophosphamide. Sequential examination revealed decreased mortality and lower incidences of severe bladder bleeding, necrosis and inflammation in Group 3. Treatment delayed until after the appearance of the cystitis, especially repeated treatments, appeared to make the cyclophosphamide-induced changes worse. Used within 1 hour of cyclophosphamide administration, before the cystitis develops, chitosan seemed to have the possibility to inhibit the appearance of hemorrhagic cystitis. In addition to the changes in the bladder, severe changes occurred in the kidneys secondary to cyclophosphamide.

Administration, Intravesical↗
PubMed1995

Functional role of nerve-derived nitric oxide in isolated dog ophthalmic arteries.

PURPOSE: To determine if nitric oxide (NO) is involved in the relaxant response to nerve stimulation by nicotine and electrical pulses in dog external ophthalmic arteries (EOA) and internal ophthalmic arteries (IOA). METHODS: Changes in isometric tension were recorded in helical strips of the arteries, and the presence of perivascular nerve containing NADPH diaphorase was histochemically demonstrated. RESULTS: Nicotine (10(-4) M, EOA and IOA) and transmural electrical stimulation (5 Hz, EOA) produced a slight or no contraction followed by a moderate relaxation in the strips contracted with prostaglandin F2 alpha. The contraction was abolished by alpha-adrenoceptor antagonists. The relaxation was abolished and the contraction was potentiated by NG-nitro-L-arginine (L-NA), a nitric oxide (NO) synthase inhibitor; the relaxation was reversed by L-arginine. Contractile response in L-NA-treated EOA was greater than in the IOA, and the relaxation was less in nontreated EOA. NO-induced relaxation and norepinephrine-induced contraction were not influenced by L-NA. There were plenty of nerve fibers visualized by NADPH diaphorase staining method in the adventitia of EOA and IOA, indicating the presence of NO synthase-containing nerves. CONCLUSIONS: The neurogenic relaxation appears to be mediated by NO released from the vasodilator nerve in EOA and IOA. There is a reciprocal innervation in vasodilator nitroxidergic and vasoconstrictor noradrenergic nerves; functionally, the latter is more predominant in EOA than in IOA.

Animals↗
PubMed1995

[Characteristics of participants in community-based rehabilitation programs and their levels of independence in activities of daily living].

To clarify characteristics of participants in community-based rehabilitation programs provided by local municipalities (cities, towns, and villages) and effect of the program on their levels of independence in activities of daily living (ADL), a cross-sectional study was performed on 422 participants in 49 municipalities in Kochi Prefecture. 1. Mean age of participants was 68.3 +/- 9.0, and 77.7% of them were stroke patients. 2. The mean interval between disease onset and program participation was 40.4 months, and the mean duration of program participation was 54.5 months. 3. At the start of rehabilitation programs and at the time of the investigation (December 1993), about 90% of the participants had good levels of independence in ADL (Rank A and over according to the standard of the Ministry of Health and Welfare). 4. The frequency of rehabilitation programs and the presence of occupational therapists were positively associated with the improvement of levels of independence in ADL. In particular, the frequency of rehabilitation programs was associated with improvement of quality of life in self-supporting participants (Rank J2), and the presence of occupational therapists was associated with the improvement of ADL in semi-bed-ridden participants (Rank A). 5. After adjusting for age and sex, using multiple logistic regression analysis, type of diseases (non-stroke), hospital rehabilitation immediately after onset, higher levels of independence in ADL at the start of rehabilitation programs, and higher frequency of rehabilitation programs were significantly associated with improvements in levels of independence in ADL. Shorter interval between disease onset and program participation, and the presence of occupational therapists were also associated with improvements in levels of independence in ADL, although the relation did not reach statistical significance.

Activities of Daily Living↗
PubMed1995

[Local cerebral blood flow and glucose metabolism during seizure in spontaneously epileptic El Mice].

Local cerebral blood flow and glucose metabolism were examined in spontaneously epileptic El mice using autoradiography with 125I-IMP and 14C-DG in the interictal phase and during seizure. El (+) mice that developed generalized tonic-clonic convulsions and El (-) mice that received no stimulation and had no history of epileptic seizures were examined. The seizure non-susceptible, maternal strain ddY mice were used as control. Uptake ratios for IMP and DG in mouse brain were calculated using the autoradiographic density. In the interictal phase, the pattern of local cerebral blood flow of El (+) mice was similar to that of ddY and El (-) mice, and glucose metabolism in the hippocampus was higher in El (+) mice than in El (-) and ddY mice, but flow and metabolism were nearly matched. During seizure, no significant changed blood flow and increased glucose metabolism in the hippocampus, the epileptic focus, and no markedly changed blood flow and depressed glucose metabolism in other brain regions were observed and considered to be flow-metabolism uncoupling. These observations have never been reported in clinical or experimental studies of epilepsy. Seizures did not cause large regional differences in cerebral blood flow. Therefore, only glucose metabolism is useful for detection of the focus of secondary generalized seizures in El mice, and appeared possibly to be related to the pathophysiology of secondary generalized epilepsy in El mice.

Animals↗
PubMed1995

[Radiotherapy for carcinoma of the esophagus in aged patients].

One hundred fifty-four patients with esophageal carcinoma were treated with either irradiation alone or irradiation combined with surgery at the University of Occupational and Environmental Health Hospital between January 1980 and February 1992. The number of patients 75 years old and older was 25. In patients 74 years old and younger, the overall five-year survival rate by Kaplan-Meier method was 24.5%. The survival rate was best in the patients who were treated by a combination of irradiation and surgery. In patients 75 years old and older, the one-year survival rate was 59%, and the three-year rate was 20%. Aged patients had a tendency to be worse in performance status, and there was no correlation between treatment modality and survival time. We conclude that radiotherapy is useful for treating esophageal cancer in aged patients particularly when maintenance of the quality of life is considered.

Adult↗
PubMed1995

Basilar arterial construction caused by intracisternal NG-nitro-L-arginine in anesthetized monkeys.

OBJECTIVES: The present study was designed to determine whether tonic nitric oxide (NO)-mediated vasodilator innervation participates in basilar arterial dilatation in the anesthetized Japanese monkey. METHODS: The basilar arterial diameter was angiographically measured, and NG-nitro-L-arginine (L-NNA), a nitric oxide synthase inhibitor, was intracisternally applied. RESULTS: The injection of L-NNA produced a sustained constriction of the basilar artery, the effect being reversed by the cisternal injection of L-arginine. The vasoconstriction tended to be accelerated by treatment with phentolamine. Under alpha-adrenoceptor blockade, hexamethonium significantly attenuated the vasoconstrictor response to L-NNA. Intracisternal injections of this inhibitor did not alter the systemic blood pressure and heart rate. CONCLUSIONS: These findings suggest that construction by the NO synthase inhibitor of the monkey basilar artery is associated with suppression of synthesis of NO in vasodilator nerves receiving tonic impulses from the central nervous system. The basilar arterial tone appears to be regulated by nitroxidergic and adrenergic nerves and by NO derived from the endothelium in anesthetized monkeys.

Angiography, Digital Subtraction↗
PubMed1994

Mechanism underlying nicotine-induced relaxation in dog saphenous arteries.

In isolated dog saphenous arterial strips denuded of the endothelium, the mechanism underlying relaxations induced by nicotine was analyzed. Nicotine-induced contractions were abolished by treatment with prazosin and alpha,beta-methylene ATP. In the strips thus treated and contracted with prostaglandin F2 alpha, nicotine produced a relaxation, which was abolished by hexamethonium. The relaxation was inhibited by cyclooxygenase inhibitors and markedly attenuated in the strips made tachyphylactic to calcitonin-gene related peptide (CGRP) but not to vasoactive intestinal polypeptide. The remaining relaxation in the strips treated with indomethacin and CGRP was abolished by NG-nitro-L-arginine, a nitric oxide (NO) synthase inhibitor, and the inhibition was reversed by L-arginine but not by D-arginine. Perivascular nerves containing NO synthase immunoreactivity have been demonstrated in an earlier report. CGRP-immunoreactive nerve fibers were observed in the adventitia. It appears that the nicotine-induced relaxation is associated with stimulation of vasodilator nerves liberating NO and CGRP, and adrenergic neurogenic vasoconstriction predominates over the neurogenic vasodilatation in dog saphenous arteries.

Animals↗
PubMed1994

Low frequency of the p53 gene mutations in neuroblastoma.

BACKGROUND: The p53 gene frequently is affected by point mutations, rearrangements, or deletions that contribute to the genesis or progression of a wide variety of human adult solid tumors; however, to the authors' knowledge, this gene alteration has not been analyzed in neuroblastoma. METHODS: Genomic DNA samples from 20 children with neuroblastoma, including 16 patients with advanced disease, were screened for the presence of mutations in exons 5-9 of the p53 gene, where over 90% of mutations have been reported to be located in human cancer. The screening technique employed polymerase chain reaction/single-strand conformation polymorphism analysis followed by direct DNA sequencing. RESULTS: Heterozygous mutations were detected in 2 of the 20 cases. A silent mutation (T to G transversion) at codon 172 and a missense mutation (G to T transversion) at codon 259 were found in patients with Stage II and Stage IV disease, respectively. Thus, p53 mutations were found to occur in neuroblastoma, but at a low frequency (2 of 20). CONCLUSIONS: Our data suggest that in a minority of neuroblastomas, p53 gene mutations may play a contributing role in tumorigenesis, but other genes presumably play a major role in this tumor.

Child↗
PubMed1994

Inhibition by calmodulin antagonists of the neurogenic relaxation in cerebral arteries.

The present study was aimed to determine the effect of calmodulin inhibitors on the relaxant response of isolated dog and monkey cerebral arteries to vasodilator nerve stimulation, which is hypothesized to be mediated by nitric oxide (NO) from nerve endings. The relaxations caused by nerve stimulation by electrical pulses in endothelium-denuded arteries were attenuated by treatment with calmidazolium and W-7 (N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide hydrochloride) and were abolished by NG-nitro-L-arginine, an inhibitor of nitric oxide synthase, and tetrodotoxin. The calmodulin inhibitors also attenuated the relaxations caused by nicotine and substance P, which were endothelium-independent and -dependent, respectively, but did not influence the relaxant response to NO. It is concluded that calmodulin is required for activation of the NO synthase present in the vasodilator nerve as well as that in the endothelium.

Animals↗
PubMed1994

Silver stained nucleolar organizer region proteins and Helix pomatia agglutinin immunostaining in esophageal carcinoma: correlated prognostic factors.

The number of nucleolar organizer region proteins identified by silver staining (AgNORs) and alterations in cell surface glycoproteins identified by Helix pomatia agglutinin (HPA) immunostaining were studied in 96 primary esophageal carcinomas. The number of AgNORs increased with increasing depth of cancer invasion, venous involvement, lymphatic invasion, and tumor stage. Positivity of HPA staining correlated significantly with increasing depth of cancer invasion, venous invasion, and tumor stage. Forty of 42 HPA negative cases had low AgNORs numbers (< 4), while 39 of 54 HPA positive cases had high AgNORs numbers (> or = 4) (P = 0.0001). The survival rate of patients with stage III and IV disease was significantly poorer for those with a high AgNORs score and HPA positivity than in those with a low AgNORs score and HPA negativity. The present study indicates that the AgNORs score is positively correlated with positive HPA staining and that tumors having both factors represent a subgroup of esophageal carcinomas with poor prognosis.

Adult↗
PubMed1994

Re-evaluation of the colorimetric assay for cytidine deaminase activity.

This study re-evaluated the colorimetric assay for cytidine deaminase (CTD), and showed that the optimum conditions were pH 7.5, 37 degrees C, and up to 24 h. In addition, this method was found to require protein precipitation. Following these modifications, intra-assay and inter-assay coefficients of variation were below 5 per cent, indicating that the assay was highly reliable. CTD activity was determined in 282 serum samples from 206 normal pregnant women by the incubation of 100 microliters of serum and 400 microliters of 1.4 mmol/l cytidine substrate for 16 h at 37 degrees C. Following protein precipitation, the ammonia liberated during conversion was measured by a colorimetric procedure. The mean (+/- SD) CTD activity was 7.31 +/- 2.50 U at 3-12 weeks of gestation, 8.70 +/- 2.12 U at 13-24 weeks, 7.59 +/- 2.25 U at 25-36 weeks, and 7.29 +/- 2.16 U at 37-42 weeks. High levels of CTD activity were found in patients with abruptio placentae and amnionitis associated with intrauterine fetal death (IUFD). The increase in CTD activity was noted from 3 days to 1 week before the confirmation of IUFD. The placenta contains extremely high levels of CTD, but cord serum does not. Thus, the excessive elevation of CTD activity was probably derived from progressive placental damage. This modified CTD assay was concluded to be simple and reliable, and may perhaps be useful in detecting pregnancy disorders.

Colorimetry↗
PubMed1994

Angiocentric lymphoma with granulomatous panniculitis in the skin expressing natural killer cell and large granular T-cell phenotypes.

We investigated three patients suffering from angiocentric lymphoma with granulomatous panniculitis in the skin. All three patients presented with multiple purple subcutaneous nodules. Immunohistologically, the lymphoma cells in all three patients expressed CD2 (T-11), CD56 (neural cell adhesion molecule), and Mik-beta 1 (interleukin-2 beta receptor). CD3s (CD3, Leu-4)-positive lymphoma cells were found in two patients. A pore-forming protein (perforin) was detected in the lymphoma cells of all three patients. Perforin-possessing lymphoid cells were focally scattered in 2 of 15 patients with CD56-negative cutaneous lymphomas who served as controls. By the Southern blot method, one patient showed a rearranged T-cell receptor (TcR)beta gene in the biopsied specimen, and the other two patients had germ-line configurations of TcRs and immunoglobulin heavy chain genes. One patient had serum anti-human T-cell lymphotropic virus (HTLV)-I antibody, but showed no integration of its proviral DNA. Ultrastructurally, membrane-bound azurophilic granules were detected in the atypical lymphoid cells of all three patients. Angiocentric lymphoma with panniculitis in three patients showed the characteristics of natural killer and large granular T-cells. The histological features might be due to the characteristics of the neoplastic cells with azurophilic granules and perforin.

Aged↗
PubMed1994

Single instillation of hydroxypropylcellulose-doxorubicin as treatment for superficial bladder carcinoma.

A single instillation of hydroxypropylcellulose (HPC)-doxorubicin (20 mg/20 ml) was performed in 20 patients with superficial bladder carcinoma. The therapeutic effect was assessed by cystoscopy at 14-30 days after the instillation, and the residual tumor tissue was resected by transurethral resection (TUR) when possible. The results obtained for the therapeutic effect were as follows: a complete response (CR), in 7 cases (35%); a reduction in size of more than 50% (partial response, PR), in 6 cases (30%); and a reduction of less than 25% in size (no change, NC), in 7 cases (35%). Combined intravesical instillation of HPC-doxorubicin and local hyperthermia using a Thermotron RF-8 was performed in 11 patients with recurrent superficial bladder carcinoma. The total number of treatment courses ranged from three to five per patient. The results obtained for the effect of this combined treatment were as follows: a CR, in 6 cases (54.5%); a PR, in 3 cases (27.3%); and NC, in 2 cases (18.2%). Therefore, the combination of intravesical instillation of HPC-doxorubicin and local hyperthermia was more effective against superficial bladder carcinoma than the single instillation of the chemotherapeutic agent alone.

Administration, Intravesical↗