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S Sawada

Publications and source records attributed to S Sawada.

At least 271 records · Page 15Linked to original sources
PubMed1992

An empirical test for the reliability of quantal analysis based on Pascal statistics.

We have previously shown that amplitude distributions of excitatory postsynaptic potentials (EPSPs) can be better described by Pascal distribution when the mean quantal content (m) is not stationary but fluctuating according to gamma distribution. We have developed the procedure of estimating quantal parameters by the method of maximum likelihood. In this study, we examined empirically the reliability of this quantal parameter estimation procedure by using Monte Carlo simulations. The reliability was evaluated by absolute values of error (magnitude of error) of estimated parameters relative to the known 'true' parameters. The mean values of relative magnitude of error were relatively small unless the probability of failures was too large (greater than 0.7) or too small (less than 0.1). The values of relative magnitude of error became smaller in association with increases in the sample size. When the probability of failure was between 0.1 and 0.7, the sample size was 1000, coefficient of variation of quantal size was 0.45, the values of relative magnitude of error of estimated parameters were below 0.1. These results mean that this procedure gives relatively reliable estimates of quantal parameters with the limitation that the probability of failure is neither too large (greater than 0.7) nor too small (less than 0.1); it is preferable that the sample size is as large as 1000.

Evoked Potentials↗
PubMed1992

Experience of a small PACS in Tottori University Hospital.

Picture archiving and communications systems (PACS) are expected to become feasible as the way of total radiologic image management. As the first step towards computerized image management, we installed an experimental small PACS with a digital optical archive for magnetic resonance and digitized radiographic film images. During the first 10 months of operation, problems were caused by the frequent mechanical troubles on the acquisition devices, impractical schemes for transmission, and troublesome retrieval and display of images. Although some of them have been solved by the improvements of both hardware and software, the mechanical instability of the digitizer and the inadequate operating procedure of the workstation still remain. As to the characteristics of PACS, the capability of access to every achieved radiologic image is the great advantage for us because the image integration has been impossible in the form of radiographic films for the traditional image management system of our hospital. However, the complicated image display procedure with high overheads is far from ideal for radiologists. The efficiency of image display must be increased to the level of a conventional film viewing system. Furthermore, research is needed on the small PACS to get consensus for the acceptance of a more widely implemented system.

Computer Systems↗
PubMed1992

Induction of "wire-loop" lesions by murine monoclonal IgG3 cryoglobulins.

We have recently demonstrated that an IgG3 rheumatoid factor (RF) monoclonal antibody (mAb), clone 6-19, derived from unmanipulated autoimmune MRL/MpJ-lpr/lpr mice, is able to generate cryoglobulins via a non-immunological IgG3 Fc interaction, and to induce an acute glomerulonephritis associated with cryoglobulinemia. Using this experimental model, we have characterized the glomerular lesions induced by the 6-19 RF monoclonal cryoglobulin, in particular the ultrastructural localization of the cryoglobulin deposits. Although their initial localization was confined to the mesangium, the 6-19 cryoglobulins were progressively accumulated in the subendothelial spaces of glomerular capillary walls, leading to the formation of glomerular lesions resembling the "wire-loop" lesion characteristically described for lupus nephritis. In addition, we have found that identical glomerular "wire-loop" lesions were induced by the 6-19-J558 hybrid antibody, composed of the 6-19 gamma 3 heavy chain and J558 lambda 1 light chain, which loses the RF activity, but retains the cryoglobulin activity. These results strongly suggest that the direct deposition of IgG3 cryoglobulins by itself, without involvement of immune complex formation, results in the generation of the classical "wire-loop" lesion characteristic of lupus nephritis. In addition, we have found that similar "wire-loop" lesions were generated by one anti-DNA mAb derived from (NZB x NZW)F1 hybrid mice, and two of four IgG3 mAb of unknown specificities, derived from MRL/MpJ-lpr/lpr mice. The absence of significant glomerular lesions, in spite of large amounts of cryoglobulins, in mice receiving two IgG3 mAb suggests the importance of physicochemical property of cryoglobulins to provoke glomerular lesions.

Animals↗
PubMed1992

Iron(II) sulphate (Fricke solution) oxidation yields for 8.9 and 13.6 keV X-rays from synchrotron radiation.

The oxidation yields (G) for 8.86 and 13.55 keV X-rays produced by synchrotron radiation were measured using an iron(II) sulphate (Fricke) solution. Monoenergetic X-rays were produced using a silicon crystal monochromator. The X-rays were absorbed in 0.4 M sulphuric acid-iron(II) sulphate solution and FeIII ion yields were measured and corrected for escape fractions resulting from scattering using Monte Carlo calculations. Doses in the solution were determined using a thin window, parallel plate chamber calibrated against a primary standard free-air chamber at the Electrotechnical Laboratory (Osaka, Japan). Yields (G) of 1.50 +/- 0.06 and 1.43 +/- 0.06 mumol J-1 were obtained for 8.86 and 13.55 keV X-rays respectively.

Oxidation-Reduction↗
PubMed1992

Effect of TPA, okadaic acid and 1 alpha,25-dihydroxyvitamin D3 on neoplastic transformation induced by 60Co gamma-rays or 252Cf fission neutrons in Balb/c 3T3 cells.

The effects of 12-O-tetradecanoylphorbol-13-acetate (TPA), 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3] and okadaic acid were individually examined on the neoplastic transformation of Balb/c 3T3 cells which were exposed to either 60Co gamma-rays or 252Cf fission neutrons. The addition of 1 alpha,25(OH)2D3, or TPA, enhanced the transformation induced by gamma-rays or low doses of fission neutrons. No enhancement was observed by the addition of okadaic acid except at toxic concentrations (5 ng/ml) and with higher doses of radiation. Moreover, the enhancement of transformation by either 1 alpha,25(OH)2D3 or TPA decreased as the radiation dose was increased. The enhancement ratio, calculated by least-square analysis from 0 Gy to 1 Gy, was greater for 1 alpha,25(OH)2D3 than for TPA, and also greater for gamma-ray irradiation than for neutron irradiation. These results suggest that the promotion of radiation-induced transformation depends on the level of the initial damage caused by radiation; and that the differences in the enhancement properties of different chemicals may be due to different individual triggering mechanisms involved in the transformation process.

3T3 Cells↗
PubMed1992

Benchmark test of transport calculations of gold and nickel activation with implications for neutron kerma at Hiroshima.

A benchmark test of the Monte Carlo neutron and photon transport code system (MCNP) was performed using a 252Cf fission neutron source to validate the use of the code for the energy spectrum analyses of Hiroshima atomic bomb neutrons. Nuclear data libraries used in the Monte Carlo neutron and photon transport code calculation were ENDF/B-III, ENDF/B-IV, LASL-SUB, and ENDL-73. The neutron moderators used were granite (the main component of which is SiO2, with a small fraction of hydrogen), Newlight [polyethylene with 3.7% boron (natural)], ammonium chloride (NH4Cl), and water (H2O). Each moderator was 65 cm thick. The neutron detectors were gold and nickel foils, which were used to detect thermal and epithermal neutrons (4.9 eV) and fast neutrons (> 0.5 MeV), respectively. Measured activity data from neutron-irradiated gold and nickel foils in these moderators decreased to about 1/1,000th or 1/10,000th, which correspond to about 1,500 m ground distance from the hypocenter in Hiroshima. For both gold and nickel detectors, the measured activities and the calculated values agreed within 10%. The slopes of the depth-yield relations in each moderator, except granite, were similar for neutrons detected by the gold and nickel foils. From the results of these studies, the Monte Carlo neutron and photon transport code was verified to be accurate enough for use with the elements hydrogen, carbon, nitrogen, oxygen, silicon, chlorine, and cadmium, and for the incident 252Cf fission spectrum neutrons.

Californium↗
PubMed1992

Meteorological observations at Hiroshima on days with weather similar to that of the atomic bombing.

An attempt to explain discrepancies between measured neutron-induced radioactivities (i.e., 152Eu, 60Co) and calculated yields based on the Dosimetry System 1986 was made by considering moist air densities at different altitudes over Hiroshima, Japan. The investigation checked the validity of moist air density estimates used in the Dosimetry System 1986 computer codes. Meteorological observations were conducted to obtain atmospheric temperature and pressure profiles for the Hiroshima area. By coupling these observations with surface measurements taken on 6 August 1945 at Ebayama Park (3.6 km from the hypocenter), estimates of temperature, pressure, and humidity at the time of detonation were derived. This allowed the calculation of densities for dry air, moist air, and water vapor. The results proved similar to the Dosimetry System 1986 estimates. Water vapor density calculations showed the largest difference (at most 7%). These results imply that the 152Eu yield contradiction in the Dosimetry System 1986 calculations vs. real measurements for large ground distances (> 900 m) is not the result of an erroneous estimate of moist air density in Hiroshima.

Cobalt Radioisotopes↗
PubMed1992

Intravascular foreign bodies: loop-snare retrieval system with a three-lumen catheter.

A foreign body retrieval system composed of a three-lumen catheter, a guide wire, and a wire loop nearly perpendicular to the axis of the catheter was used to retrieve catheter fragments located in the inferior vena cava in two patients and in the superior vena cava in one patient. Fragments were looped within 1 minute of catheterization and were retrieved without complication. Catheter fragments placed in the pulmonary artery of one dog were also successfully retrieved.

Animals↗
PubMed1992

Chemical modification of an antitumor alkaloid, 20(S)-camptothecin: glycosides, phosphates and sulfates of 7-ethyl-10-hydroxycamptothecin.

Water-soluble derivatives having the lactone ring intact were synthesized starting from 7-ethyl-10-hydroxycamptothecin (1). Glycosides (2) of the phenolic hydroxyl group of 1 were obtained by reaction with acetylated alpha-bromosugars in acetone or aqueous acetone in the presence of potassium carbonate, followed by deprotection. Phosphates (3) were prepared by reaction of 1 with phosphoryl chloride in pyridine or with dibenzylchlorophosphoridate. Sulfates (4) were obtained by reaction of 1 with sulfur trioxide-pyridine complex in the presence of a tertiary amine. The organic ammonium salts of monophosphate (3p) and sulfates (4a and 4b) showed significant activity against L1210 in vivo.

Animals↗
PubMed1992

Influence of endothelin on human platelet aggregation and prostacyclin generation from human vascular endothelial cells in culture.

The effects of endothelin (ET) on the function of cultured human umbilical vein endothelial cells (HUVEC) and that of human platelets were investigated with reference to endothelium-derived relaxing factor (EDRF) and PGI2. Considering the platelets, ET had no effect on platelet-rich plasma (PRP) aggregation, the generation of thromboxane A2 ([TXA2]) from platelets, and cytosolic free calcium ion concentration ([Ca++]i), cAMP content ([cAMP]i) or cGMP content ([cGMP]i) in platelets. In contrast, the addition of the solution in which HUVEC had been incubated with ET to PRP produced a decrease in PRP aggregation, [TXA2], and [Ca++]i, and an increase not only in [cAMP]i but also in [cGMP]i in platelets. In the HUVEC pretreated with acetylsalicylic acid (aspirin), this increase of [cGMP]i was not affected, but the HUVEC-mediated decrease in PRP aggregation, [TXA2], and [Ca++]i induced by ET were not completely abolished. However, the pretreatment of HUVEC with a combination of aspirin and L-NG-monomethyl arginine (LNMMA) as an inhibitor of EDRF completely abolished the HUVEC-mediated decrease in PRP aggregation, [TXA2] and [Ca++]i induced by ET, and also abolished the enhancement of [cGMP]i and [cAMP]i in platelets. The PGI2 of HUVEC was enhanced by ET with no changes in [Ca++]i, [cAMP]i and [cGMP]i. The ET-induced enhancement was remarkably attenuated by pretreating the HUVEC with aspirin, but not with LNMMA. We conclude that ET attenuates the aggregation of platelets through a decrease in [TXA2] by an increase in [cAMP]i via the increase in PGI2 of HUVEC, and by an increase in [cGMP]i via EDRF.

Blood Platelets↗
PubMed1992

Questionnaire surveys of cases of tick bite and Lyme borreliosis in hunters in Hokkaido with reference to detection of anti-Borrelia burgdorferi antibody.

An epidemic of Lyme borreliosis on Hokkaido island, Japan, was surveyed by questionnaire in 587 hunters. The 308 returns (52.4%) revealed episodes of tick bite (usually 2 or more) in 210 cases. Skin rashes appeared in 164 cases. Associated itching, pain, etc., but not skin rash, were more frequent after 2 or more tick bite. Previous determinations of anti-Borrelia burgdorferi antibody titers in these subjects and in controls suggested an association with outdoor activities other than hunting, and among 33 cases of dermatological symptoms and 23 of articular symptoms, 4 and 2, respectively, were antibody-positive. Most of these antibody-positive subjects had suffered tick bite at least twice, but had had no antibiotic treatment. Three subjects with joint disorders were antibody-positive. These findings suggested that the many hunters exposed to Borrelia burgdorferi frequently carried latent infections, and that some had latent form of arthritis, dermatitis and other disorders.

Adult↗
PubMed1992

Effects of famotidine on various immunological parameters in patients with rheumatic diseases: decreased lymphocyte DR expression by famotidine.

We examined the effect of famotidine, a histamine-type 2 receptor antagonist, on the immunocompetent cells. The number of DR(+) cells were significantly decreased in patients with systemic lupus erythematosus (P less than 0.05) by parenteral administration of famotidine (40 mg/days for 4 weeks). However, total lymphocyte number and monocyte number did not change. Immunoglobulin levels of patients with rheumatoid arthritis and normal male did not change. Furthermore, phytohemagglutinin induced lymphocyte proliferation was increased by addition of famotidine (10 ng/ml). Nonetheless, famotidine did not have mitogenic function itself to lymphocyte and did not affect IL-2 production.

Adjuvants, Immunologic↗
PubMed1992

[Repeated arterial infusion chemotherapy for inoperable hepatocellular carcinoma using implantable drug delivery system].

We performed a clinical evaluation of repeated arterial infusion chemotherapy using an implantable drug delivery system for 41 patients with inoperable hepatocellular carcinoma (HCC). About half of our patients could not undergo transcatheter arterial embolization (TAE) because of extreme tumor extension and/or accompanying advanced cirrhosis. In most patients we implanted a 5 Fr. catheter non-surgically and connected it to an implanted injection port through a subcutaneous tunnel. The treatment schedule was weekly or biweekly intrahepatic one-shot administration of mitomycin C, adriamycin, 5-fluorouracil and epirubicin. The response rate (CR + PR) was 24.4%. The median survival period was 401.1 days. The 6 month, 1-year and 2-year survival rates were 73%, 48% and 24%, respectively. There were no severe side effects nor complications. The implantable drug delivery system will contribute not only to improved therapeutic efficacy for inoperable HCC but also improve the quality of life for patients.

Adult↗
PubMed1992

[Lobenzarit disodium (CCA)--induced diabetes insipidus in a patient with rheumatoid arthritis].

A 44-year-old female with 16-year history of rheumatoid arthritis visited Akiru Hospital with complaints of a thirst, a dry mouth and a general fatigue. One week prior to admission, the patient manifested excessive thirsty feeling, a body weight loss and a sleepless by the polyuria. She has been given 5-10 mg of prednisolone and 240 mg of lobenzarit disodium (CCA) in a day for 11 months. A hematologic examination showed no abnormality, and the examination of her serum showed the following values: BUN, 9.3 mg/dl; creatinine, 0.9 mg/dl; sodium, 139 mEq/l; chloride, 102 mEq/l; potassium, 3.9 mEq/l; osmolality, 290 mOsm/l. Plasma antidiuretic hormone (ADH) level increased slightly (6.0 pg/ml). Examination of her urine revealed specific gravity, 1.005; no trace of glucose, protein, blood and ketones; normal sediment; and osmolality, 209 mOsm/l. The patient was given exogenous ADH (10 units of vasopressin tannate in oil, intramuscularly) to obtain a diagnosis, and she was found to be unable to concentrate her urine more than 1.008 in the specific gravity. A water restriction, as a test for diabetes insipidus, also failed to concentrate her urine in the specific gravity and in the osmolality. Together with these findings, the patient was diagnosed to be a diabetes insipidus, and CCA was seemed to account for the disease. This unfavorable effect of CCA appeared to be reversible, since the patient recovered her urinary concentrating ability after the medication of CCA was discontinued.

Adult↗
PubMed1992

[The pharmacokinetics of intraperitoneal (IP) carboplatin (CBDCA) and dose-up study of intravenous (IV) cyclophosphamide (CPM) in combination with IP CBCDA for advanced ovarian cancer patients].

The pharmacokinetics of IP CBDCA was compared with IV CBDCA and a dose-up study of IV CPM was performed in combination with 400 mg/m2 IP CBDCA for advanced ovarian cancer patients. The maximum concentration of free platinum (F-Pt) in serum following IP CBDCA administration was approximately 1/3 that of F-Pt following IV CBDCA. F-Pt in serum remained more than 90% of total platinum following IP CBDCA until 12 hours after administration. The t1/2 of F-Pt in serum after IP CBDCA administration was two times longer when compared with t1/2 following IV CBDCA, showing the slow peritoneal clearance of CBDCA. The area under curve (AUC) following IP CBDCA was approximately 67% of AUC following IV CBDCA. Cumulative urinary secretion (CUS) of platinum following IP CBDCA was 37% of CUS after IV CBDCA. The maximum tolerable dose of IV CPM in combination with 400 mg/m2 IP CBDCA was 550-600 mg/m2. The dose limiting factor of this combination therapy was leukocytopenia. Thrombocytopenia was mild in this study. Combination of 400 mg/m2 IP CBDCA and 550-600 mg/m2 seemed to be a tolerable and repeatable therapy for most patients with advanced ovarian carcinoma. Since thrombocytopenia was mild and the pharmacokinetics showed the smaller AUC of free platinum in serum following IP CBDCA, a dose-up study for IP CBDCA should be considered.

Adenocarcinoma↗
PubMed1992

[Evaluation of hypercoagulable state in patients with malignancies by using prothrombin fragment F1 + 2].

In order to elucidate the activation of the coagulation cascade in patients with malignant neoplasms, we measured the levels of plasma prothrombin fragment F1 + 2, which is liberated in the process of thrombin generation. Twenty healthy adults (Group A), 29 patients with malignancies not complicated with DIC (Group B) and 4 patients with DIC (Group C) were evaluated. The values of F1 + 2 in Group C (2.38 +/- 0.55 nmol/l) were significantly higher (p < 0.01) than those in Group A (0.52 +/- 0.19 nmol/l) and B (0.86 +/- 0.68 nmol/l). Many patients in Group B showed higher levels of F1 + 2 compared to normal subjects, however, no significant differences were found between Group A and B. With respect to other coagulation molecular markers such as TAT, D-Dimer and PIC, F1 + 2 levels revealed positive correlation to those levels. Concerning the clinical course of DIC, elevated levels of F1 + 2 normalized much rapidly than those of TAT and D-Dimer by continuous administration of heparin. In conclusion, the measurement of plasma F1 + 2 is important in monitoring the activation of coagulation system in patients with malignancies, especially with respect to early detection and treatment of DIC.

Aged↗
PubMed1992

[Adequate Ca level for dialysis patient (study on medical therapy for secondary hyperparathyroidism in dialysis patient)].

We evaluated our medical therapy of secondary hyperparathyroidism (2 degrees HPT) in dialysis patients. Ten hemodialysis patients with 2 degrees HPT (PTH-C; higher than 10ng/ml) were treated with vitamin D3, large amounts of phosphate binders and calcitonin and data over three years were examined. Our data showed that 2 degrees HPT is manageable by medical therapy. Furthermore, we suggest that the adequate Ca level for dialysis patients is to maintain the Ca (mEq/1) xP (mg/dl) at less than = 35. When plasma P is less than 6mg/dl. The maintenance of this Ca level successfully treated 2 degrees HPT, and this prevent the appearance of renal osteodystrophy (ROD) in dialysis patients.

Adult↗