Fetal thermal effects of diagnostic ultrasound.

Processes that can produce a biological effect with some degree of heating (ie, about 1 degrees C above the physiologic temperature) act via a thermal mechanism. Investigations with laboratory animals have documented that pulsed ultrasound can produce elevations of temperature and damage in biological tissues in vivo, particularly in the presence of bone (intracranial temperature elevation). Acoustic outputs used to induce these adverse bioeffects are within the diagnostic range, although exposure times are usually considerably longer than in clinical practice. Conditions present in early pregnancy, such as lack of perfusion, may favor bioeffects. Thermally induced teratogenesis has been shown in many animal studies, as well as several controlled human studies; however, human studies have not shown a causal relationship between diagnostic ultrasound exposure during pregnancy and adverse biological effects to the fetus. All human epidemiologic studies, however, were conducted with commercially available devices predating 1992, that is, with acoustic outputs not exceeding a spatial-peak temporal-average intensity of 94 mW/cm2. Current limits in the United States allow a spatial-peak temporal-average intensity of 720 mW/cm2 for fetal applications. The synergistic effect of a raised body temperature (febrile status) and ultrasound insonation has not been examined in depth. Available evidence, experimental or epidemiologic, is insufficient to conclude that there is a causal relationship between obstetric diagnostic ultrasound exposure and obvious adverse thermal effects to the fetus. However, very subtle effects cannot be ruled out and indicate a need for further research, although research in humans may be extremely difficult to realize.     

Spanish newsreel NO-DO (1943-1975). The diffusion of science as a legitimizing instrument of the Franco regime: polio and other immuno-preventable diseases

The official NO-DO newsreels were screened in Spain on a weekly basis from 1943 to 1981. These official news and documentary programmes were compulsory in cinemas from the moment they were first produced until the end of the Francoist dictatorship (1975). NO-DO held an information monopoly and was used as the regime's propaganda tool to indoctrinate the population, building stories tailored to the regime's interests and masking social realities. In this study, we examined newsreels on medical subjects relating to diseases preventable by vaccination. A majority of reports centred on poliomyelitis, and two differentiated periods could be defined, coinciding with the development of Franco regime's foreign policy. Further, from the gender perspective, we analyse the female stereotypes in the battle against vaccine preventable diseases Therefore, the news coverage of polio is of special relevance. In conclusion, this topic offers a good opportunity to reflect on the political role of popular science and science communication in a specific historical context.     

A model evaluation study for treatment planning of laser-induced thermal therapy

Abstract

A cross-validation analysis evaluating computer model prediction accuracy for a priori planning magnetic resonance-guided laser-induced thermal therapy (MRgLITT) procedures in treating focal diseased brain tissue is presented. Two mathematical models are considered. (1) A spectral element discretisation of the transient Pennes bioheat transfer equation is implemented to predict the laser-induced heating in perfused tissue. (2) A closed-form algorithm for predicting the steady-state heat transfer from a linear superposition of analytic point source heating functions is also considered. Prediction accuracy is retrospectively evaluated via leave-one-out cross-validation (LOOCV). Modelling predictions are quantitatively evaluated in terms of a Dice similarity coefficient (DSC) between the simulated thermal dose and thermal dose information contained within N?=?22 MR thermometry datasets. During LOOCV analysis, the transient model’s DSC mean and median are 0.7323 and 0.8001 respectively, with 15 of 22 DSC values exceeding the success criterion of DSC?≥?0.7. The steady-state model’s DSC mean and median are 0.6431 and 0.6770 respectively, with 10 of 22 passing. A one-sample, one-sided Wilcoxon signed-rank test indicates that the transient finite element method model achieves the prediction success criteria, DSC?≥?0.7, at a statistically significant level.     

Thermal enhancement of low dose rate irradiation in a murine tumour system

The effects of localized hyperthermia (HT) in combination with low dose rate irradiation (brachytherapy) have been investigated in vivo using a murine mammary adenocarcinoma. Flank tumours were grown to 0.45–0.70 cm³ in volume, at which time their treatment course was initiated. Tumours were locally heated in a water bath for 15 min at either 44 or 45°C. For tumour irradiations a non-invasive cap was devised to permanently house three iodine-125 sealed sources located at 120° intervals around the circumference of the hemispherical cap. During treatment, mice were secured in a modified syringe tube allowing mobility while restricting access to the cap which was placed over the tumour. Calculated dose rates ranged from 15 to 40 cGy/h. Brachytherapy (BT) was delivered for 48 or 72 h to obtain a dose range of 830–2378 cGy. Mice were randomized into one of 10 treatment protocols: BT alone, HT-BT, BT-HT, HT-BT-HT, 1/2BT-HT-1/2BT, four control groups of HT alone and a sham treatment group. Normalized tumour doubling volume growth delays (GD_Dv) were used to calculate the thermal enhancement ratios (TER). In the 44°C experiments, HT before BT (TER= 1.33 ±0.071) was more efficacious than HT after BT (TER=1.07 ±0.042). Two HT treatments, one given before and one after BT (TER = 1.38 ± 0.152), were not different from a single HT treatment given before BT. However, a single HT treatment given in the middle of an interrupted course of BT resulted in the greatest thermal enhancement (TER=1.64±0.072) compared to any other treatment sequence. These data suggest that potentiation of low dose rate irradiation by a single heat treatment may be maximized if the HT is given either in the middle of, or simultaneously with, the BT.     

藏药吉堪明目液毒理研究

目的:通过藏药吉堪明目液的急性毒性、长期毒性与眼部刺激性实验,观察其毒性反应。方法:观察吉堪明目液对小鼠灌胃,测定最大耐受量的毒性反应;对家兔短期多次滴眼(15min/次,2h)与常规治疗7d滴眼(3次/d,7d)对兔眼的刺激情况;以1.1g/kg、0.56g/kg、0.28g/kg剂量组连续滴眼(4次/d)30天后,观察家兔每周体重、重要脏器系数、血象、血生化指标变化及眼球、重要脏器的病理检测。结果:吉堪明目液对小鼠最大耐受量(MTD)为生药39g.kg-1,无任何不良反应;短期多次给药眼刺激和常规治疗7天给药刺激性试验对兔眼角膜、虹膜、结膜综合评分为0,均无刺激作用,眼球病理检测无异常;连续滴眼30天后外观行为、每周体质量、血液学和血液生化学、脏器系数、与空白组比较无明显差异;眼球和脏器病理检测未发现与药物相关的明显病变,停药后也未见药物延迟毒性反应。结论:本藏药制剂未发现毒性反应,其临床应用是安全和无刺激的。     

State-of-the-Art Management of Acute Bleeding Peptic Ulcer Disease

The management of patients with non variceal upper gastrointestinal bleeding has evolved, as have its causes and prognosis, over the past 20 years. The addition of high-quality data coupled to the publication of authoritative national and international guidelines have helped define current-day standards of care. This review highlights the relevant clinical evidence and consensus recommendations that will hopefully result in promoting the effective dissemination and knowledge translation of important information in the management of patients afflicted with this common entity.