• Title/Summary/Keyword: low dose effect

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The Dielectric Properties of OPP film due to Irradiation Aging (방사선 열화에 따른 이축연신 폴리프로필렌 필름의 유전특성)

  • 오세원;조경순;김용주;김왕곤;홍진웅
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1993.11a
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    • pp.80-84
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    • 1993
  • In this research, we studied the variation of the dielectric loss absorption of the dielectric loss absorption of the sample according with the change to $\^$60/Co-${\gamma}$-ray irradiation dose of the influence of temperature and applied voltage. In order to investigate the effect of irradiation oriented polypropylene film, we have observed dissipation factor within the temperature range of 30∼130 [$^{\circ}C$] and voltage range of 100∼250$^{\circ}C$ [V]. As for the dependency of temperature by dissipation factor, the ${\alpha}$-peak which appears at high temperature increases accordingly to the increasement of irradiation dose which is contributed by the crystal region and moves towards the high temperature. The ${\beta}$-peak which appears at low temperature is origined from dipoles and molecular motions in the amorphous region. As for the dependency of voltage by tan$\delta$, at low temperature the peak of the tan$\delta$, at low temperature the peak of the tan$\delta$ shifts accordingly to the increasement of irradiation dose towards the high temperature region.

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Development of a One-step Two-site Enzyme Immunoassay for Measuring Human Alpha-fetoprotein by Eliminating Hook-effect

  • Kim, Se-Ho
    • BMB Reports
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    • v.34 no.1
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    • pp.47-50
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    • 2001
  • A one-step, two-site enzyme immunoassay was developed for measuring human alpha-fetoprotein (AFP) in serum and amniotic fluid using monoclonal antibodies (McAb) by eliminating the high-dose hook effect. Three McAbs that recognize different epitopes were selected among 16 different clones on the basis of epitope mapping, two for immobilization and one for horseradish peroxidase conjugation. This one-step immunoassay system is more convenient and rapid compared to a conventional two-step sandwich immunoassay system. It did not exhibit the hook effect to around 2.7 mg/ml of AFP, which is probably one of the highest concentrations of AFP in the serum. The dose-response curve of the system was linear to 500 mg/ml of AFP and the system could differentiate as low as 1 mg/ml of AFP The intra- and inter-assay variations were in an acceptable range; 95~104% and 97~105% respectively Its correlation with other commercial systems was around 95%.

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Studies on the anti-infiammatiry activity and its mechanism of daidzein (Daidzein의 항염작용과 그 작용기전에 관한 연구 (II))

  • 허인회;이상준;김형춘
    • YAKHAK HOEJI
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    • v.31 no.3
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    • pp.164-172
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    • 1987
  • The anti-inflammatory mechanism of daidzein was investigated in rats and mice. Daidzein and 4'-methyldaidzein inhibited capillary permeability and lipid peroxidation. Daidzein inhibited growth of granuloma when it was administered into the carrageenin pouch at the low dose, while it acted contrarily at the high dose. Daidzein decreased the antiinflammatory effect in adrenalectomized rat, depleted ascorbic acid and cholesterol contents in adrenals, and increased corticosterone level in plasma, suggesting dadzein acts on the hypophysisadrenal system.

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Dose-Rate Effects Generated from Repair and Regeneration (재생과 증식에 기인하는 선량률 효과)

  • Yi Pon Nyong;Cho Kwan Ho;Marks Richard D.;Kim Jae Ho
    • Radiation Oncology Journal
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    • v.7 no.2
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    • pp.171-183
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    • 1989
  • A general effect for cell proliferation has been incorporated into Roesch's survival equation (Accumulation Model). From this an isoeffect formula for the low dose-rate regimen is obtained. The prediction for total doses equivalent to 60Gy delivered at the constant dose-rate over 7 days agrees well with the dose-time data of Paterson and of Green, when the parameter ratio A/B (${\approx}{\alpha{\mu}}/2{\beta}\;where\;{\mu}$ is the repair rate) is chosen to be 0.7Gy/h. When a constant proliferation rate and known facts of division delay are assumed, an isoeffect relation between low dose-rate treatment and acute dose-rate treatment can be derived. This formula in the regimens where proliferation is negligible predicts exactly the data of Ellis that 8 fractions of 5 Gy/day for 7 days are equivalent to continuously applied 60Gy over 7days, provided the A/B ratio is 0.7 Gy/h and the $\alpha/\beta$ ratio is 4Gy. Overall agreement between the clinical data and the predictions made by the formula at the above parameter values suggests that the biologcal end points used as the tolerance level in the studies by Paterson, Green, and Ellis all agree and they are not entirely the early effects as generally assumed. The absence of dose-rate effects observed in the mouse KHT sarcoma can better be explained in terms of a large value for the A/B ratio. Similarly, the same total dose used independently of the dose-rate to treat head and neck tumors by Pierquin can be justified.

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Low doses of amitriptyline, pregabalin, and gabapentin are preferred for management of neuropathic pain in India: is there a need for revisiting dosing recommendations?

  • Kamble, Sanjay Vasant;Motlekar, Salman Abdulrehman;D'souza, Lyndon Lincoln;Kudrigikar, Vinay Nanda;Rao, Sameer Eknath
    • The Korean Journal of Pain
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    • v.30 no.3
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    • pp.183-191
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    • 2017
  • Background: Current therapy for the treatment of neuropathic pain is often unsatisfactory. Considerable variation in treatment pattern still exists in spite of availability of sufficient literature from various guidelines. Recent Indian market data suggested that the utilization (sale) of drugs such as amitriptyline, pregabalin, and gabapentin was more for low-dose unit packs than that of the high-dose unit packs, raising the belief that these drugs are prescribed at a lower dose than is actually recommended in the guidelines. To test this hypothesis, a survey was conducted across speciality throughout the country to observe the prescription pattern of these drugs amongst the health care providers in India. Methods: Three hundred fifty survey forms were distributed of which 281 forms were included for analysis. Results: It was observed that the commonly used initiation and maintenance dose for amitriptyline, pregabalin, and gabapentin was 5-10 mg/day, 50-75 mg/day, and 100-300 mg/day, respectively. The reason to select the lower dosages was to have a balancing effect to achieve good efficacy with minimum side effects. Care-givers reported no side effects/not many side effects as a reason in 22.2%, 16.88%, and 23.86% patients with amitriptyline, pregabalin, and gabapentin, respectively. Sedation and giddiness were commonly reported with all three drugs. Conclusions: Commonly prescribed drugs for management of neuropathic pain, such as amitriptyline, pregabalin, and gabapentin are preferred at lower doses in Indian clinical settings. Acceptable efficacy and low tolerance to the standard dosage is believed to be the reason behind the prescribed dose.

Antidiabetic Activity of Formula Containing Euonymus Alatus (Thunb.) Sieb. and Mori Folium in Multiple Low Dose Streptozotocin-induced Diabetic Rats (저용량 스트렙토조토신 유도 당뇨 흰쥐에서 화살나물.상엽 복합 처방의 항당뇨 활성)

  • 김희자;이성현;정성현
    • YAKHAK HOEJI
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    • v.48 no.4
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    • pp.247-253
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    • 2004
  • We investigated the hypoglycemic effect of formula containing Euonymus alatus (EA) and Mori Folium (MF) in multiple low dose (MLD) streptozotocin (STZ)-induced diabetic rats. In order to iduce hyperglycemic state 25 mg/kg of STZ was injected intraperitoneally for 5 consecutive days. SD rats were randomly divided into diabetic control and treatment groups. Treatment groups were administered with either 250 mg/kg of EA and 250 mg/kg of MF (E1Ml), or 500 mg/kg of EA mixed with same dose of MF (E2M2) for 3 weeks. Blood glucose levels and body weights were measured every 5th or 6th day. E1Ml and E2M2 both significantly reduced food intake, water intake, and fasting blood and urine glucose levels as compared to those in diabetic control group in a dose dependent manner. Body weight in diabetic control group was increased slightly after 3 weeks. Treatment group, however, showed gradual increase in body weights during 3 week-period. While plasma insulin levels of the diabetic control group were decreased to the level of 387$\pm$14 pg/ml from 534$\pm$36 pg/ml, those levels in E1Ml and E2M2-treated groups were both markedly increased by 13% and 26%, respectively. Urine glucose levels in E1Ml and E2M2-treated groups were also remarkably reduced by 17 and 26% compared to the levels of diabetic control group. While expression of membrane-bound glucose transporter-4 (GLUT-4) protein in skeletal muscle was reduced by 45% in diabetic control compared to the normal control, GLUT-4 protein expressions in E1Ml and E2M2-treated groups were augmented by 2 and 3.5 times compared to the diabetic control, respectively. Pancreatic HE staining experiments showed that E2M2-treated group revealed much less infiltrated mononuclear cells, indicating that E2M2 efficiently blocked insulitis induced by multiple low dose streptozotocin. Taken together, we conclude that formula containing EA and MF may prevent or delay the development of hyperglycemia through overexpression of GLUT-4 protein in skeletal muscle and prevention of insulitis.

DIFFERENTIAL EXPRESSION OF RADIATION RESPONSE GENES IN SPLEEN, LUNG, AND LIVER OF RATS FOLLOWING ACUTE OR CHRONIC RADIATION EXPOSURE

  • Jin, Hee;Jin, Yeung Bae;Lee, Ju-Woon;Kim, Jae-Kyung;Lee, Yun-Sil
    • Journal of Radiation Protection and Research
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    • v.40 no.1
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    • pp.25-35
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    • 2015
  • We analyzed the differential effects of histopathology, apoptosis and expression of radiation response genes after chronic low dose rate (LDR) and acute high dose rate (HDR) radiation exposure in spleen, lung and liver of rats. Female 6-week-old Sprague-Dawley rats were used. For chronic low-dose whole body irradiation, rats were maintained for 14 days in a $^{60}Co$ gamma ray irradiated room and received a cumulative dose of 2 Gy or 5 Gy. Rats in the acute whole body exposure group were exposed to an equal dose of radiation delivered as a single pulse ($^{137}Cs$-gamma). At 24 hours after exposure, spleen, lung and liver tissues were extracted for histopathologic examination, western blotting and RT-PCR analysis. 1. The spleen showed the most dramatic differential response to acute and chronic exposure, with the induction of substantial tissue damage by HDR but not by LDR radiation. Effects of LDR radiation on the lung were only apparent at the higher dose (5 Gy), but not at lower dose (2 Gy). In the liver, HDR and LDR exposure induced a similar damage response at both doses. RT-PCR analysis identified cyclin G1 as a LDR-responsive gene in the spleen of rats exposed to 2 Gy and 5 Gy gamma radiation and in the lung of animals irradiated with 5 Gy. 2. The effects of LDR radiation differed among lung, liver, and spleen tissues. The spleen showed the greatest differential effect between HDR and LDR. The response to LDR radiation may involve expression of cyclin G1.