Calculation of non-stationary temperature fields in tissue in the application of cryotherapy — a contribution to therapy planning

Mathematical models of non-stationary temperature fields in living tissue can supply pre-operative recommendations and reference values for the exact planning of cryotherapy (therapy parameters; time, applicator size, applicator shape, working temperature, etc.). Hence it is possible to estimate the possibilities and limits for attaining a particular cryotherapeutic effect. This is particularly important for oncological indications because an insufficient therapeutic dosage (e.g. applicator too small, temperature not low enough, inappropriate freezing rate or therapy time too short) may result in the stimulation effect occurring at the most extreme periphery of the freezing zone and becoming effective in the tumour's marginal zone. This must be prevented at all events. Even the impact of the various tissue and device parameters on the temperature distribution can be defined with the aim of correctly judging the significance of the individual parameters in therapy.     

氟尿嘧啶外涂与干扰素注射联合液氮冷冻治疗多发性跖疣的疗效及对患者免疫功能的影响

目的:探讨氟尿嘧啶外涂与干扰素注射联合液氮冷冻治疗多发性跖疣的疗效及对患者免疫功能的影响。方法:将78例多发性跖疣患者分为两组,每组39例。对照组采用液氮冷冻联合氟尿嘧啶外涂。观察组在对照组基础上,给予注射干扰素。观察两组皮损变化情况。对比两组治疗前后T淋巴细胞水平变化。采用DLQL法评估患者生存质量变化。 结果: 观察组的疗效显著优于对照组,差异有统计学意义（Z=2.312,P<0.05）;观察组治疗后CD3、CD4、CD4/CD8显著升高（P<0.05）;治疗后,观察组的CD3、CD4、CD4/CD8显著高于对照组,差异有统计学意义（P<0.05）;观察组治疗后皮损评分、DLQL评分显著降低（P<0.05）;治疗后,观察组的皮损评分、DLQL评分显著低于对照组,差异有统计学意义（P<0.05）。结论:氟尿嘧啶外涂与干扰素注射联合液氮冷冻治疗多发性跖疣的疗效确切,能显著提高患者免疫功能。     

基于低温冷冻治疗仪的温度测量方法

采用热电偶信号放大器AD595结合K型热电偶温度传感器,设计基于低温冷冻治疗仪的热电偶测温电路;实现了冷端自动补偿、温度曲线升降功能;测量电路结构简单、成本较低,具有较强的实用性。     

The Abscopal Effect in the Era of Checkpoint Inhibitors

Therapy targeting immune checkpoints represents an integral part of the treatment for patients suffering from advanced melanoma. However, the mechanisms of resistance are responsible for a lower therapeutic outcome than expected. Concerning melanoma, insufficient stimulation of the immune system by tumour neoantigens is a likely explanation. As shown previously, radiotherapy is a known option for increasing the production of tumour neoantigens and their release into the microenvironment. Consequently, neoantigens could be recognized by antigen presenting cells (APCs) and subjected to effector T lymphocytes. Enhancing the immune reaction can trigger the therapeutic response also at distant metastases, a phenomenon known as an abscopal effect (from “ab scopus”, that is, away from the target). To illustrate this, we present the case of a 78-year old male treated by anti-CTLA-4/ipilimumab for metastatic melanoma. The patient received the standard four doses of ipilimumab administered every three weeks. However, the control CT scans detected disease progression in the form of axillary lymph nodes metastasis and liver metastasis two months after ipilimumab. At this stage, palliative cryotherapy of the skin metastases was initiated to alleviate the tumour burden. Surprisingly, the effect of cryotherapy was also observed in untreated metastases and deep subcutaneous metastases on the back. Moreover, we observed the disease remission of axillary lymph nodes and liver metastasis two months after the cryotherapy. The rarity of the abscopal effect suggests that even primed anti-tumour CD8⁺ T cells cannot overcome the tumour microenvironment’s suppressive effect and execute immune clearance. However, the biological mechanism underlying this phenomenon is yet to be elucidated. The elicitation of a systemic response by cryotherapy with documented abscopal effect was rarely reported, although the immune response induction is presumably similar to a radiotherapy-induced one. The report is a combination case study and review of the abscopal effect in melanoma treated with checkpoint inhibitors.     

Short‐term effect of cryotherapy on human scleral tissue by atomic force microscopy

This study investigated the inflammatory effect of cryotherapy application on collagen matrix network in human infant sclera. Donor scleral tissues taken from three infant patients divided into five groups: control group, sham‐treated group, and three cryotreated groups. In the cryotherapy groups, the sclera was treated for 5 s, 10 s, and 20 s with ?80°C freezing by a cryosurgical system. The cryotreated reactions were examined using double histological analysis with hematoxylin‐eosin and Masson's trichrome, and atomic force microscopy analysis to quantify the diameter and D‐banding of collagen fibrils. The infant scleral tissues treated with cryotherapy showed a significantly increased collagen density associated with inflammatory response (p < 0.05), increased fibril diameter (p < 0.005) compared to the scleral tissues in the control group. The results directly suggest that the cryotherapy affects the morphology of scleral collagen. SCANNING 35:302‐307, 2013. © 2012 Wiley Periodicals, Inc.     

Progress in cryosurgery

Cryosurgery (in situ freezing), the controlled cryogenic destruction of tissues in situ rather than their removal by conventional surgical excision, has been efficaciously employed for the treatment of numerous benign and malignant neoplasms. Studies have indicated the participation of an immunologic response to antigens of the frozen tissue, ie cryoimmunization, as contributing to cryodestruction. Following a cursory overview of the background and rationale for studies of the immunologic phase of cryodestruction, consideration is given to recent experimental and clinical studies contributing to our further understanding and application of cryoimmunization as a therapeutic modality.     

基于单片机C8051F020控制的低温冷冻治疗仪

介绍一种基于C8051F020单片机控制的低温冷冻治疗仪,重点阐述低温冷冻治疗仪的温度测量电路、报警电路、通信接口电路以及LCD与单片机的接口显示电路结构及原理。结果表明该低温冷冻治疗仪使用方便、结构简单、成本较低、可靠性高,可显示、可报警;治疗仪性能可靠,使用方便,对研究低温冷冻治疗具有重要的临床应用价值。