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61.
用放射化学分析方法,对新疆核试验场周围10个调查区和远离核试验场位于上风向的5个对照区采取的土壤样品进行了90Sr、137Cs分析测定。核试验场周围调查区土壤中90Sr累积平均沉降量为1.5×103Bqm-2,137Cs为4.9×103Bqm-2;对照区90Sr累积平均沉降量为1.3×103Bqm-2,137Cs为3.9×103Bqm-2。调查区和对照区表层土壤中州90Sr,137Cs放射性平均水平无显著性差异。通过估算得出了调查区90Sr、137Cs对居民产生约定有效剂量当量分别为78.3μSv(集体剂量当量负担为23.9人·sv)和270μSv(集体剂量当量负担为82.3人·sv),对照区分别为70.5μSv,(集体剂量当量负担为14.1人·sv)和220μSv(集体剂量当量负担为14.1人·sv)。两个地区居民受到来自核试验产生的90Sr和137Cs给予人体的内照射剂量当量负担基本上是一样的。可认为90Sr、137Cs对新疆核试验场周围没有造成严重的局部污染。对居民的身体健康不致于产生不良影响。 相似文献
62.
ABSTRACT An ultrasensitive thyrotropin (TSH) assay was used to determine how many of 65 patients with primary hypothyroidism on thyroxine (T4) replacement therapy had suppressed serum TSH. In 13 patients (20%) TSH levels ≤0.1 mlU/l were found, indicating an overdose of thyroxine. After correction of the dose, 48 patients had normal TSH values. Their mean dose of thyroxine was 119 μg/24 hours, and the appropriate replacement dose tended to decline with advancing age. The serum level of thyroid hormones during replacement therapy with thyroxine very imperfectly reflected serum TSH values. It is concluded that overdose of thyroxine is common when suppressed serum TSH is used as an end point. Biochemical follow-up of replacement therapy with thyroxine in primary hypothyroidism therefore requires the use of an ultrasensitive TSH assay in order to detect such suppression. Serum levels of thyroxine or triiodothyronine (T3) during thyroxine therapy are poor indicators of pituitary TSH secretion and are therefore not useful as parameters of adequate thyroxine dosage. 相似文献
63.
Dennis D. Rasmussen 《Brain research bulletin》1991,26(4):663-666
It has been proposed that endogenous opioid peptide (EOP) inhibition of hypothalamic GnRH secretion mediates and is dependent upon gonadal steroid feedback of LH secretion, although considerable conflicting data have been reported. Accordingly, a well-characterized replacement regimen was used to approximate physiological stimulation by estradiol (E2) and progesterone (P4) in adult rats 10 days after ovariectomy (OVX), followed by in vitro incubation of the isolated median eminence to evaluate the role of E2 and P4 in modifying GnRH release in response to the opiate receptor antagonist, naloxone (NAL). Basal (control) GnRH release from median eminences of OVX, OVX + E2, and OVX + E2 + P4 rats was similar, and NAL treatment elicited a comparable increase in GnRH release under all three gonadal steroid conditions. Thus, EOP suppression of median eminence GnRH secretion does not appear to mediate or be dependent upon negative feedback regulation of LH secretion by physiological concentrations of gonadal steroids. 相似文献
64.
Objective To study the altered radiobiological effect of simulative intensity-modulated radiotherapy (SIMR) in cultured human nasopharyngeal carcinoma (NPC) cells and the related mechanism. Methods Single cell suspension of exponentially growing CNE-2 cells, a poor differentiated NPC cell line, was seeded and cultured for 12 hours, then the cells were irradiated in two different models by 6 MV X-ray beams at 3 Gy/min. In single fraction irradiation (SFR) model, cells were irradiated a single fraction of 0, 2, 4, 6 or 8 Gy within 0 to 3 minutes. In S1MR model, cells were irradiated 0, 2, 4, 6 or 8 Gy in 5 frac-tions with interval of 8.0-8.5 minutes between. Clonogenic assay was performed to determine the radiosen-sitivity. Cellular apoptosis was measured by flow cytometry. RT-PCR was used to detect mRNA expressions of Bax and Bcl-2, Respectively. Results Compared with SFR group, the survival fraction in SIMR group was higher at all the dose levels. The values of α, β, D0 and Dq were higher in SIMR group than in SFR group. At dose levels of 2 Gy, 4 Gy and 6 Gy, The early and late apoptotic cells in SIMR group were lower than in SFR group (21.20%: 15.89%, F=18.51, P=0.020;13.00%: 10.20, F=15.67, P=0.040).The mRNA expression of Bax was upregulated in a dose-dependent manner in the both groups. Compared with SFR group, the mRNA expression of Bax in SIMR group was lower at all the dose levels (Mean value of 76.75% : 62.50%, F =36.57, P =0.000). Bcl-2 mRNA expression at every dose level had no significant difference between the two groups (Mean value of 29.25% : 29.75%, F=0.74, P=0.800). Conclusions Prolonged delivery time in SIMR model can decrease the radiobiological effects. 相似文献
65.
单次静注爱肌松(0.3mg·kg-1,对照组)于3.17±0.81分钟(x±s)可获得满意的气管插管条件。预注组(10例)首次量0.27mg·kg-1于预注剂量(0.03mg·kg-1)后5分钟给予,可使爱肌松的起效时间缩短至0.93±0.17分钟(P<0.001),TOF无反应期、25%和90%恢复时间两组无显著差别(P>0.25)。全部病例均获得了良好的气管插管条件,预注的优点还在于能评估患者对所选用非去极化肌松药的敏感性。预往后TOF肌电图T1抑制>10%较无明显TOF抑制者肌松恢复时间显著延长(P<0.05)。同时发现吸入安氟醚可使爱肌松作用时效延长。 相似文献
66.
为确定放射性碘在甲状腺内滞留模式,观察甲状腺吸收放射性碘后的生物效应,进而评价其辐射危害。方法利用活体测量方法,直接测量两个不同年龄组大鼠甲状腺内131Ⅰ的代谢参数。对测量数据进行处理后得到了大鼠甲状腺内131Ⅰ的滞留函数为三指数项函数。结果利用所得三指数项滞留函数的准确方法进行剂量估算,所得的两组动物的甲状腺平均累积吸收剂量分别为7.7Gy和11.5Gy,而一般方法算得的大鼠甲状腺的平均累积吸收剂量比用准确方法高估了66%~91%。结论由于准确方法考虑到影响估算甲状腺所受剂量的一些因素,故可相对准确地反映了131Ⅰ所致不同年龄大鼠甲状腺的吸收剂量。 相似文献
67.
68.
两种剂量奥曲肽治疗食管及胃曲张静脉出血效果比较 总被引:1,自引:1,他引:0
①目的 比较两种剂量奥曲肽治疗食管、胃曲张静脉出血的临床效果。②方法 将 88例食管、胃曲张静脉出血病人随机分为奥曲肽 5 0 μg/h和 2 5 μg/h剂量组 ,观察平均止血时间、止血率、再出血率和不良反应。 ③结果 5 0 μg/h组平均止血时间明显短于 2 5 μg/h组 (t=2 .2 4 ,P <0 .0 5 ) ,总止血率明显高于 2 5 μg/h组 (χ2 =5 .36 0 ,P <0 .0 5 ) ,再出血率较 2 5 μg/h组低 (χ2 =7.990 ,P <0 .0 5 )。两组均有 1例病人出现恶心。④结论 奥曲肽 5 0 μg/h剂量治疗食管、胃曲张静脉出血的效果优于 2 5 μg/h剂量 相似文献
69.
In children with acute obstructive lung disease gas exchange is affected by ventilation-perfusion mismatch and the degree of bronchoconstriction. Standard lung function measurements do not reflect the impairment in gas exchange. Alternatively, the effective pulmonary blood flow (EPBF), that is, the proportion of the cardiac output that is supplying well-ventilated lung units, can give accurate and noninvasive estimates of ventilation-perfusion mismatch. We measured EPBF with the argon freon ?22 rebreathing technique in children with acute severe asthma to assess their response to nebulized salbutamol and to determine whether induced changes in the EPBF could be predicted from baseline measurements. Twenty-four children admitted with an acute asthma attack had spirometry and triplicate EPBF measurements before and after nebulized salbutamol. Eighteen patients had repeated tests 50 days later when fully recovered; 4 patients were taking methylxanthines on at least one occasion. The mean forced expiratory volume in 1 sec (FEV1) rose from 55% of predicted to 66% after salbutamol and to 83% with recovery. The mean coefficients of variation for EPBF measurements on the three test occasions were 11.3%, 8.2%, and 9%. Except in children on methylxanthines, the EPBF values were reduced during the acute asthma attack (median, 2.53 L/min/m2; range, 1.99–3.60 L/min/m2) compared with paired values obtained after recovery (median, 2.89 L/min/m2; range, 2.2Eb4.04 L/min/m2) (P = 0.009). Salbutamol caused a highly significant increase in EPBF from 2.88 L/min/m2 (range, 1.86–3.80) before treatment to 3.34 L/min/m2 (range, 2.264.65) immediately afterwards (P = 0.0003). The spirometric indices did not relate to the changes in the EPBF values. However, when the effective stroke volume index was calculated in 11 patients, the changes induced by nebulized salbutamol had a significant inverse relation with the pretreatment FEV, (P = 0.61; P = 0.02). In conclusion, the argon freon-22 rebreathing technique can be used successfully and reproducibly to measure EPBF in children with an acute asthma attack. Except in children taking methylxanthines, EPBF during the acute attack is reduced and rises significantly after salbutamol. EPBF values after recovery were significantly higher than the presalbutamol values during the attack. Spirometric indices do not relate to the EPBF changes but are inversely related to the effective stroke volume changes. Pediatr Pulmonol. 1994; 17:370–377. © 1994 Wiley-Liss, Inc. 相似文献
70.