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T Okawa

Publications and source records attributed to T Okawa.

At least 55 records · Page 3Linked to original sources
PubMed1998

[A trial to reduce cardiac motion artifacts on HR-CT images of lung with combined use of subsecond scan and a high temporal resolution reconstruction algorithm].

PURPOSE: To reduce cardiac motion artifacts with combined use of subsecond CT scanning and a high temporal resolution algorithm. SUBJECTS AND METHODS: Scan data were obtained with step-by-step scanning (scan time, 0.8 seconds). Two sets of images were reconstructed, with and without high temporal resolution reconstruction algorithm (HTRR), from the same set of scan data. HTRR, derived from modification of 180-degree linear helical interpolation, reduces full width at half maximum (FWHM) to half of the scan time. Motion artifacts of two sets of images were compared. RESULTS: The use of HTRR seemed to be useful in reducing cardiac motion artifacts owing to the improvement of effective time resolution. However, there were some images without significant reduction of cardiac motion artifacts. CONCLUSION: Our technique is useful in reducing cardiac motion artifacts without an increase in radiation exposure.

Algorithms↗
PubMed1998

[Radiotherapy for locally advanced esophageal cancer].

The conventional treatment for patients with locally advanced esophageal cancer has been surgery or radiotherapy. The indication of the treatment depends on the location of the primary tumor, tumor stage, resectability of the lesion and operability of the patient. Radiotherapy is used in a case refusing surgery, medical contraindications to surgery, extensive locoregional disease or poor general condition. The survival rate by surgery alone or radiotherapy alone is poor. Thus, single modality therapy is not a standard treatment, but combined multimodal therapy including chemotherapy is a standard approach for locally advanced esophageal cancer. Further studies of optimization of multimodal therapies which are surgery and/or radiotherapy combined with chemotherapy are needed to improve the results in the treatment of esophageal cancer.

Brachytherapy↗
PubMed1998

[Demonstration of normal bile duct and pancreatic duct with MR cholangiopancreatography].

Demonstration of normal bile duct and pancreatic duct with MR cholangiopancreatography was assessed in 78 patients including 19 cases of not impacted gallstone. Breath hold 2D-MRCP and intermittent breath hold 3D-MRCP was performed with half-Fourier fast spin echo technique using 1.5 T imager and surface coil. Diagnostic depiction rates of main pancreatic duct were 99% in the head, 97% in the body, and 91% in the tail, and of extrahepatic bile duct was 100%. Visualization of accessory pancreatic duct was 42%, but of side branch of pancreatic duct in the body to tail was poor. Anatomic variants of the biliary tree were seen in 15 cases. The reason of poor demonstration was the poor breath hold. In the majority of patients, MRCP can provide the accurate information of pancreaticobiliary tract without dilatation.

Adolescent↗
PubMed1997

Insulin-like growth factors I and II are autocrine factors in stimulating proteoglycan synthesis, a marker of differentiated chondrocytes, acting through their respective receptors on a clonal human chondrosarcoma-derived chondrocyte cell line, HCS-2/8.

Both insulin-like growth factor (IGF)-I and IGF-II increased the synthesis of cartilage-type, large proteoglycan in a human chondrosarcoma-derived chondrocyte cell line, HCS-2/8. In contrast to the stimulatory effects of IGFs on costal chondrocytes of the young rabbit, the stimulatory effect of IGF-II on proteoglycan synthesis in HCS-2/8 cells was more potent than that of IGF-I. IGF-II, but not IGF-I, increased calcium influx into HCS-2/8 cells, and there was a close relation between the stimulation of proteoglycan synthesis and the calcium influx. [125I]IGF-I bound to HCS-2/8 cells, and this binding was competitively inhibited by low concentrations of unlabeled IGF-I, higher concentrations of IGF-II, and much higher concentrations of insulin. [125I]IGF-II also bound to the cells, and its binding was competitively inhibited by IGF-II and slightly inhibited by higher concentrations of IGF-I and much higher concentrations of insulin. When radioligand-receptor complexes were separated by SDS-PAGE and subjected to autoradiography, two major bands at 260 and 130 kDa were observed, which correspond to the IGF type II receptor (IGF-IIR) and the alpha subunit of the IGF type I receptor (IGF-IR), indicating the presence of both receptors. When confluent cultures of HCS-2/8 cells were maintained in serum-free medium, proteoglycan synthesis did not decrease unless the medium was repeatedly replaced. Conditioned medium of HCS-2/8 cells stimulated the HCS-2/8 cells to synthesize proteoglycans. RIA revealed that the cells produced both IGF-II and IGF-I. Transcripts of messenger RNAs of both IGF-I and IGF-II and both IGF-IR and IGF-IIR also were detectable by Northern analysis. Both anti-IGF-IR antibody and anti-IGF-II antibody inhibited proteoglycan synthesis. Mannose-6-phosphate, which is known to bind to IGF-IIR, stimulated proteoglycan synthesis, potentiated IGF-II-stimulated proteoglycan synthesis, and enhanced the binding affinity for IGF-II but not for IGF-I. Even in the presence of anti-IGF-IR antibody, IGF-II and mannose-6-phosphate stimulated proteoglycan synthesis in the cells. [Leu27]IGF-II, an IGF-II analogue with high affinity only for IGF-IIR, strongly stimulated proteoglycan synthesis in HCS-2/8 cells but [Arg54, Arg55]IGF-II, which binds to only IGF-IR, also stimulated proteoglycan synthesis in the cells. These findings indicate that IGF-I and IGF-II act as autocrine differentiation factors for this chondrocytic permanent cell line, HCS-2/8, mainly via respective receptors.

Analysis of Variance↗
PubMed1997

Single-photon emission CT and MR findings in Klüver-Bucy syndrome after Reye syndrome.

We present the MR and single-photon emission CT findings in a 3-year-old patient in whom Klüver-Bucy syndrome developed after Reye syndrome. MR images showed diffuse brain atrophy, which was predominant in the temporal lobes, and single-photon emission CT scans showed decreased cerebral perfusion in the bilateral temporal lobes and associated cortical areas.

Agnosia↗
PubMed1997

[Clinical evaluation of intra-arterial infusion chemotherapy for advanced or recurrent cervical cancer with or without radiotherapy].

We analyzed 52 cases of advanced or recurrent cancer of the cervix treated by intra-arterial infusion chemotherapy (IAIC) with or without radiotherapy. IAIC regimen was separated into two groups: Group I consisted of 5-FU + MMC +/- ADR (30 cases) and group II of CDDP + MMC +/- 5-FU (22 cases). The tip of the catheter was placed in the bifurcation of abdominal aorta or the bilateral internal iliac arteries (7 cases). The overall response rate (CR + PR) was 71%, 87% in patients given radiotherapy, 50% in those without radiotherapy, and 100% in primary cases. The five-year survival rate was 20% in primary cases, 14% in recurrent cases, 3% in Group I and 38% in Group II (p = 0.00182) by chemotherapy regimen. Severe (more than grade III) hematological acute side effect was 48% for all cases, but recovered by interruption of drugs. In 7 cases in which the tip of the catheter was placed in internal iliac arteries, there were severe skin ulcers in 2 cases and severe pain of leg or gluteal region requiring narcotics in 2 cases. These data suggest that IAIC mainly with cisplatin with or without radiotherapy is one of the effective treatments for advanced or recurrent cervix cancer. But we should check the blood flow distribution periodically, and control the concentration of drugs.

Adenocarcinoma↗
PubMed1997

[Clinical evaluation of chemoradiotherapy for advanced cervical cancer].

Locally advanced cervical cancer has a poor prognosis, poor survival rate, and high local failure rate. A number of questions regarding the optimal agents and schedule of concurrent chemoradiation remain unanswered. To improve the cure rate for advanced or recurrent cervix cancer, we studied intra-arterial infusion chemotherapy (IAIC) with or without radiotherapy. We analyzed 52 cases of advanced or recurrent cervical cancer treated by IAIC with or without radiotherapy. IAIC regimen was separated into two groups: group I consisted of 5-FU + MMC+/-ADM (30 cases) and group II of CDDP + MMC+/-5-FU (22 cases). The tip of the catheter was placed in the bifurcation of abdominal aorta or the bilateral internal iliac arteries (7 cases). The overall response rate (CR + PR) was 71%, 87% in patients receiving radiotherapy, 50% in those without radiotherapy, and 100% in primary cases. The five-year survival rate was 20% in primary cases, 14% in recurrent cases, 3% in group I and 38% in group II by chemotherapy regimen. Severe (more than grade III) hematological acute side effects were found in 48% of all cases, but recovered by interruption of drugs. In 7 cases in which the tip of the catheter was placed in internal iliac arteries, there were severe skin ulcers in 2 cases and severe pain of leg or gluteal region which need narcotics in 2 cases. These data suggest that IAIC mainly with cisplatin with or without radiotherapy is one of the effective treatments for advanced or recurrent cervical cancer. But we should check blood flow distribution periodically, and control the concentration of drugs. To improve the survival rate for advanced or recurrent cervical cancer, we should discuss neoadjuvant chemotherapy followed by chemoradiotherapy and maintenance systemic chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Mastoparan elicits prostaglandin E2 generation and inhibits inositol phosphate accumulation via different mechanisms in rabbit astrocytes.

The effects of mastoparan on phosphoinositide hydrolysis and prostaglandin E2 (PGE2) generation were investigated in astrocytes cultured from rabbit brain. Mastoparan inhibited the accumulations of [3H]inositol phosphates induced by bradykinin (1 microM) in a time- and concentration-dependent manner. Mastoparan (3-30 microM) also released PGE2 in a time- and concentration-dependent manner. Mastoparan-induced release of PGE2 was inhibited by indomethacin, a cyclooxygenase inhibitor, by dexamethasone, a steroidal anti-inflammatory drug, and by pertussis toxin, an inactivator of some G proteins, such as Gi and Go. Mastoparan also caused [3H]arachidonic acid liberation, which was inhibited by dexamethasone or pertussis toxin. In contrast, indomethacin, dexamethasone and pertussis toxin failed to attenuate mastoparan-induced inhibition of [3H]inositol phosphate accumulation induced by bradykinin. Thus, mastoparan-induced inhibition of phosphoinositide hydrolysis does not involve pertussis toxin-sensitive G protein nor arachidonic acid metabolites. In addition to the inhibition of phospholipase C, mastoparan activates phospholipase A2 through pertussis toxin-sensitive G protein.

Animals↗
PubMed1996

Excitatory response of rabbit myometrium to nitric oxide in vitro.

Nitric oxide (NO) at high concentration (approx. 33 microM) produced a marked excitation: increase of tension development or increase in amplitude of spontaneous contraction, in 7 out of 8 rabbit nonpregnant myometrial strips. One case produced an inhibition: disappearance of spontaneous contraction. A latent period of several sec usually preceded the excitation. The response of the myometrium to NO approx. 33 microM associated with remarkable increase in tissue cyclic GMP levels. NO approx. 33 microM reduced an inhibition, in 1 out of 3 myometrial strips taken from ovariectomized rabbits. Two cases produced an excitatory. A precursor of NO, L-Arginine 100 microM or an inhibitor of NO synthase, NG-nitro-L-arginine 100 microM also produced a transient weak excitatory response. On the contrary, 8-bromo-cyclic GMP 100 microM produced an inhibition. The excitatory response to NO 33 microM was almost unaffected by pretreatment with indomethacin 10 microM, whereas the spontaneous motility was remarkably depressed. The contractile response of the isolated rabbit myometrium to electrical field stimulation was almost unaffected by the pretreatment with L-arginine 100 microM or NG-nitro-L-arginine 100 microM. The present findings may indicate that NO has inhibitory and excitatory components on the mechanical activity of the rabbit isolated myometrium.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1996

[Clinical evaluation of intra-arterial infusion chemotherapy for advanced or recurrent pelvic tumors with or without radiotherapy].

We analyzed 97 cases of various advanced or recurrent pelvic tumors which were cervix, rectal, ovarian and other tumors treated by intra-arterial infusion chemotherapy (IAIC) with or without radiotherapy. The IAIC regimen was separated into two groups: group I consisting of 5-FU + MMC +/- ADR (54 cases) and group II consisting of CDDP + MMC +/- 5-FU (43 cases) from 1985. The catheter was placed in the bifurcation of abdominal aorta, and from 1990, the catheters were placed in bilateral internal iliac arteries (8 cases). The overall response rate (CR + PR) was 65%, 74% in patients receiving radiotherapy, and 47% in those without radiotherapy. There were no significant differences between each primary site and presence of radiotherapy combination in survival rate. Two-year survival rate and 5-year survival rate was 32% and 15% for all cases, and 65% and 33% for CR cases, respectively. A significantly better survival rate was obtained in patients with CR. Five-year survival rate was 4% in group I, and 35% in group II (p = 0.00216) by chemotherapy regimen. Severe (more than grade III) hematological acute side effects were 45% for all cases. In 8 cases in which the catheters were placed in internal iliac arteries, there were severe skin ulcers in 2 cases, and severe pain of leg or gluteal region requiring narcotics in 3 cases. These data suggest that IAIC mainly with cisplatin with or without radiotherapy is one of the effective treatment for advanced or recurrent pelvic tumors. Also, we should check blood flow distribution periodically, and control the concentration of drugs.

Adolescent↗
PubMed1995

Effects of endothelins on mechanical activity and inositol phosphate production in pregnant rat myometrium.

Endothelins (ETs) caused concentration-dependent contraction in pregnant rat myometrium. ET-2 was as potent as ET-1 in affecting contractile responses, whereas ET-3 was considerably less potent than ET-1 or ET-2. ETs also increased inositol phosphate (IP) production in a dose-dependent manner, with IP production paralleling the contractile response. The rank order of potency for both the contractile responses and IP production was ET-1 = ET-2 > ET-3. When we compared the important oxytocic agent oxytocin, we found that oxytocin (10(-7) M) strongly increased contractility and IP production, and the responses were comparable to those elicited by ET-1 (10(-7) M) and ET-2 (10(-7) M). These results suggest that ET-induced myometrial contraction involves phospholipase C activation, and that a subtype of endothelin receptor existing in pregnant rat myometrium could be classified as ETA.

Animals↗
PubMed1995

Factors affecting the occurrence of urothelial tumors in dye workers exposed to aromatic amines.

BACKGROUND: Past studies have analyzed individual jobs in dyestuff factories, materials manufactured and handled, age at exposure, and the duration of exposure in factories as factors related to the occurrence of urothelial tumors. None of these studies was based on long-term observation, and the factors involved in the occurrence of urothelial tumors remain controversial. In this study, various factors that may affect the occurrence of urothelial tumors in dye workers were assessed by multivariate analysis. METHODS: Three hundred and sixty-three workers in nine member factories of the Dyestuff Industrial Cooperative Association were included the study. Factory A is a large dyestuff chemical factory in Wakayama City with 218 dye workers. The other eight smaller factories employ a total of 145 dye workers. Correlations of tumor occurrence with a variety of factors, such as dyestuff intermediates manufactured and handled, types of job in the factory, age at the beginning of occupational exposure, and the duration of exposure were examined by multivariate analysis using multiple logistic models. RESULTS: Urothelial tumors were found in 58 (16.0%) of the 363 dye workers in the nine member factories of the Cooperative Association examined in the present study. The incidence in workers in Factory A, 5.5% (12 patients), was significantly (P < 0.01) lower than the overall incidence, while that in the eight small factories, 31.7% (46 patients), was significantly (P < 0.01) higher than the overall incidence. The risk factors significantly related to tumor occurrence in the 363 dye workers were benzidine (odds ratio, 8.302) as a dyestuff intermediate, manufacturing work (odds ratio, 4.631), and a long period of exposure (odds ratio, 1.018). Correlations of the tumor occurrence with the various factors were examined by multivariate analysis using multiple logistic models. In the total of 363 workers, benzidine as an intermediate (P < 0.05), manufacturing work (P < 0.01) and the duration of exposure (P < 0.01) were found to have contributed to the urothelial tumor occurrence. In Factory A, benzidine as an intermediate (P < 0.01) and duration of exposure (P < 0.05) contributed significantly to tumor occurrence. CONCLUSIONS: 1) The manufacturing and handling of benzidine and duration of exposure contribute significantly to the occurrence of occupational urothelial tumor, the former more strongly than the latter; 2) the contribution of different job types to tumor occurrence may be dependent upon the industrial health and safety practices in each factory.

Adolescent↗
PubMed1995

Superficial esophageal cancer: multicenter analysis of results of definitive radiation therapy in Japan.

PURPOSE: To assess the effectiveness of definitive radiation therapy in patients with superficial esophageal cancer. MATERIALS AND METHODS: Method of irradiation, local control rate, survival rate, and complications were assessed in 105 patients (89 men, 16 women; age range, 50-88 years) with superficial esophageal cancer treated with definitive radiation therapy at 15 hospitals in 1981-1990. RESULTS: All lesions were confirmed to be squamous cell carcinoma. The overall 5-year survival rate was 38.7%; the 5-year disease-specific survival rate was 71.0%. The 2-year local control rate was 83.0%. Late complications occurred in 16 patients. The prevalence of complications was relatively high in the group treated with intraluminal radiation therapy. CONCLUSION: Local control and survival rates in patients treated with radiation therapy were excellent, especially in the group treated with external and intraluminal radiation therapy; however, the optimal dose and optimal combination of external and intraluminal radiation therapy should be further assessed.

Aged↗
PubMed1995

[The role and future of radiotherapy in cancer treatment].

The basic principle of radiotherapy for cancer patients is that it has the possibility of a good result (curability), is tolerable and promises a comfortable life thereafter. Radiotherapy is the important tool for early stage cancer by conserving the organ and function and for an advanced or recurrent stage of cancer by helping improve the quality of life. Radiotherapy must be planned on the basis of considering the therapeutic ratio with a 3-dimensional technique. It should be performed with optimum radiation methods in the multimodal treatment of cancer and will undoubtedly prove effective in the future.

Clinical Trials, Phase III as Topic↗
PubMed1995

[Influence of endotoxin on sensitivity to oxytocin in pregnant rat myometrium].

In order to clarify the mechanism of preterm labor induced by intrauterine infection, we studied the effect of endotoxin on oxytocin sensitivity of the myometrium in the pregnant rat. We administrated bacterial endotoxin obtained from Escherichia coli to the pregnant rat at preterm. By using a myometrial strip, we determined the effect of oxytocin on contractility, production of prostaglandins (PGs) and phosphoinositide hydrolysis. 1. Endotoxin increased myometrial sensitivity to oxytocin in the pregnant rat at preterm. The pD2 value was equal to that of myometrium taken from term pregnant rat. This hypersensitivity was significantly inhibited by indomethacin. 2. In the myometrial strips from rats to which endotoxin was administered, the concentrations of PGF2 alpha and PGE2 had already developed a tendency to increase during spontaneous contractions, when compared to the controls. There was seen a significant additional increase due to oxytocin. PGF2 alpha production was also significantly inhibited by indomethacin. 3. Oxytocin significantly stimulated total inositol phosphate production in a dose-dependent manner in myometrium taken from preterm pregnant rat. The inositol 1.4.5-trisphosphate production stimulated by oxytocin significantly increased in comparison to the controls. These results suggest that not only the production of PGs but phosphoinositide hydrolysis of transmembrane signaling pathways would play an important role in the mechanism of myometrial contraction at preterm when intrauterine bacterial infection developed.

Animals↗
PubMed1995

[Current consideration and future in radiotherapy].

The basic principle of radiotherapy for cancer patients is that it has the possibility of a good result (curability), tolerable and promises a comfortable life thereafter. Radiotherapy is the important tool for cancer by conserving the organ and function and by helping improve the quality of life. Radiotherapy must be planed on the basis of considering the therapeutic ratio with a 3-dimensional treatment planning technique which is an important role in radiotherapy because they are essential in target localization. Radiotherapy is leading the way in cancer treatment for today and tomorrow.

Forecasting↗