中国人恶性高热家系蓝尼定受体-1基因的筛查

目的 筛查中国人恶性高热(MH)家系的蓝尼定受体-1(RYR1)基因.方法 提取确诊为MH的先证者及家系其他成员外周血白细胞的基因组DNA,采用PCR扩增先证者RYR1基因的部分外显子,并进行直接测序,采用Fok Ⅰ限制酶分析验证先证者及家系其他成员基因突变情况.结果 先证者RYR1基因第6 724位碱基C突变为T(c.6724 C＞T),所编码第2 206位氨基酸由苏氨酸变为甲硫氨酸(p.T 2206 M),此突变在白种人已报道;先证者的4个子女中有2个为该错义突变携带者,为MH易感者.结论 中国人MH易感者携带与白种人MH易感者相同的RYR1基因突变.     

Effect of transient scrotal hyperthermia on sperm parameters,seminal plasma biochemical markers,and oxidative stress in men

In this experimental prospective study, we aimed to analyze the effect of transient scrotal hyperthermia on the male reproductive organs, from the perspective of sperm parameters, semen plasma biochemical markers, and oxidative stress, to evaluate whether different frequencies of heat exposure cause different degrees of damage to spermatogenesis. Two groups of volunteers (10 per group) received testicular warming in a 43°C water bath 10 times, for 30 min each time: group 1: 10 consecutive days; group 2: once every 3 days. Sperm parameters, epididymis and accessory sex gland function, semen plasma oxidative stress and serum sex hormones were tested before treatment and in the 16-week recovery period after treatment. At last, we found an obvious reversible decrease in sperm concentration (P = 0.005 for Group 1 and P= 0.008 for Group 2 when the minimums were compared with baseline levels, the same below), motility (P = 0.009 and 0.021, respectively), the hypoosmotic swelling test score (P = 0.007 and 0.008, respectively), total acrosin activity (P = 0.018 and 0.009, respectively), and an increase in the seminal plasma malondialdehyde concentration (P = 0.005 and 0.017, respectively). The decrease of sperm concentration was greater for Group 2 than for Group 1 (P = 0.031). We concluded that transient scrotal hyperthermia seriously, but reversibly, negatively affected the spermatogenesis, oxidative stress may be involved in this process. In addition, intermittent heat exposure more seriously suppresses the spermatogenesis compared to consecutive heat exposure. This may be indicative for clinical infertility etiology analysis and the design of contraceptive methods based on heat stress.     

我国大陆恶性高热病例的分析

目的 分析我国大陆恶性高热（MH）病例的临床资料，探讨诊断和治疗中应注意的问题。方法 检索中国生物医学文献数据库，收集1978年1月至2004年3月报道的MH病例34例，分析其流行病学特征、发病特点、临床表现、治疗及转归。结果 我国大陆报道的MH病例以青少年居多，男性多于女性，集中在口腔科手术（尤其是唇腭裂修补术）、骨科手术和小儿外科手术（尤其是先天畸形矫治术），典型的临床表现为突然发生的高碳酸血症、体温急剧升高和骨骼肌僵直等。诊断上主要是根据临床表现，尚未建立骨骼肌体外收缩试验方法，治疗上主要是对症处理，缺乏特效药物（丹曲林）。结论 近几年我国大陆MH病例逐渐增加，应加强对MH发病机制的研究，尽快建立MH的实验诊断标准，增强预防、诊断和治疗MH的能力。     

Effect of interstitial laser hyperthermia in a murine model of colorectal liver metastases

Interstitial laser hyperthermia (ILH) is an in situ ablative technique used for the treatment of colorectal liver metastases. At present, few data exist concerning the optimum power settings required to maximize tissue necrosis.The aim of this study was to establish the dose-response relationship between the laser power setting and the extent of tissue necrosis produced in liver and tumor tissue, as well as the pattern of necrosis in a murine model of liver metastases. An intrasplenic induction model of liver metastases in 4- to 6-week-old male inbred CBA mice was used. Laser hyperthermia was applied to liver and tumor tissue using a bare optical quartz fiber from a Laserex SLY500 Nd:YAG surgical laser generator. Two-watt and 5-watt power settings were used at specific time intervals. The livers were then excised, fixed in formalin, and the extent and degree of necrosis were measured. Results were expressed as mean ? standard deviation and were normally distributed. Analysis of variance was performed, and the least significant difference was used for post hoc tests. A P value of less than 0.05 was considered significant. Interstitial laser hyperthermia at 5 watts of power produced larger diameters of necrosis than did 2 watts for specific exposure times in normal liver tissue. However, when the total energy applied was compared, there was no significant difference in the diameters of tissue necrosis produced by the two power settings. The diameter of tissue necrosis in the normal liver increased from 2 mm at 10 joules to 8 mm at 600 joules of energy. Within tumor tissue, ILH at 2 and 5 watts produced similar diameters of necrosis for specific exposure times. When amounts of total energy applied were compared, ILH at the lower power setting (2 watts) produced a significantly larger diameter of necrosis than the higher power setting (5 watts). The diameter of necrosis achieved in tumor tissue was significantly larger than that in normal liver tissue at both power settings, for an equivalent amount of applied energy. The difference was more pronounced when ILH was performed at the lower power setting. The maximum diameter of necrosis achieved was 6.8 ± 0.7 mm in normal liver tissue and 7.7 ± 0.8 mm in tumor tissue. Charring of the fiber tip was delayed when the lower power setting was used, occurring after 20 seconds of exposure, compared to 5 seconds at the higher power setting. Similarly, cavitation occurred initially at 50 seconds at 5 watts of power and was delayed until 90 seconds of exposure at 2 watts of power. Histopathologic findings revealed an elliptical area of homogeneous necrosis, with a central acellular coagulum surrounded by intact but nonviable tissue. ILH is capable of producing highly reproducible, uniform, and complete tissue necrosis. The diameter of necrosis is related to the total energy applied. At low-power settings at any given amount of applied energy, a significantly larger diameter of tissue necrosis was achieved in tumor tissue compared to normal liver tissue.     

Pathophysiological role of the serotonin system in malignant hyperthermia

Br J Anaesth 2001; 87: 793–7     

Pathological findings in 165 patients explored for malignant hyperthermia susceptibility

The pathological findings in 165 patients explored for malignant hyperthermia (MH) susceptibility are reported. The first group of 120 subjects were patients investigated for MH. These patients had suffered an attack of MH under anaesthetic or were members of families in which a subject had died of MH. In vitro contracture tests revealed 25 malignant hyperthermia susceptible (MHS) subjects, with positive contracture tests for halothane and caffeine, 5 malignant hyperthermia subjects with reaction to caffeine only (MHC), 3 malignant hyperthermia subjects with reaction to halothane only (MHH) and 87 malignant hyperthermia negative (MHN) subjects with normal contracture tests. The second group of 45 subjects had exertional heat stroke. In vitro contracture tests performed at least 3 months after the exertional heat stroke revealed 11 MHS, 6 MHC, 2 MHH subjects and 26 MHN. In both groups, whatever the in vitro contracture test results, pathological findings were heterogeneous and revealed various changes: rhabdomyolysis, mitochondrial myopathy, denervation, type II atrophy, AMPase deficiency, non-specific findings or normal features. Central core myopathy was only observed in the first subgroup and was the only disease significantly associated with MH. In contrast to previous reports, this study demonstrates the absence of a specific malignant hyperthermia or exertional heat stroke myopathy. Furthermore, the discovery of MHS subjects among the EHS group of patients highlights the need for systematic exploration of all these patients.     

Characterization of PEG–iron oxide hydrogel nanocomposites for dual hyperthermia and paclitaxel delivery

Hyperthermia, the heating of tissue from 41 to 45?°C, has been shown to improve the efficacy of cancer therapy when used in conjunction with irradiation and/or chemotherapy. In this work, hydrogel nanocomposites have been developed that can control the delivery of both heat and a chemotherapeutic agent (e.g. paclitaxel). The nanocomposites studied involve a stealth, poly(ethylene glycol) (PEG)-based system comprised of PEG (n?=?1000) methyl ether methacrylate and PEG (n?=?400) dimethacrylate with iron oxide nanoparticles physically entrapped within the hydrogel matrices. The capability of the hydrogel nanocomposites to be heated in an alternating magnetic field was demonstrated. The heating of the hydrogel systems was dependent on the crosslinking of the hydrogel network where hydrogels with lower swelling ratios were found to heat to a greater extent than those with higher ratios. In addition, paclitaxel was shown to exhibit non-Fickian release from the hydrogel systems, with the amount of drug released dependent on the hydrogel network structure. Three cell lines: M059K (glioblastoma), MDA MB 231 (breast carcinoma), and A549 (lung adenocarcinoma) were exposed to paclitaxel only, hyperthermia only, and both paclitaxel and hyperthermia to determine if a synergistic cytotoxic effect was possible for these cell lines. The efficacy of paclitaxel was greater with hyperthermia for the A549 cells; however, the M059K and MDA MB 231 did not show the same response.     

Hyperthermic Enhancement of Tumor Radiosensitization Strategies

Local hyperthermia of living tissue can cause significant increases in blood flow and oxygenation depending on time-temperature history. Increases in perfusion of the abnormal and insufficient vasculature found in solid tumors may increase tumor oxygenation, thereby increasing the radiation sensitivity of the tumor. We hypothesized that local heating of tumor would increase the oxygenation of the tumor tissue and allow other oxygenating agents to further modify tumor oxygenation and radiation response. In the present study the effect of moderate temperature hyperthermia (MTH) at 41.5–42.5°C for 30–60 min, 250 mg/kg nicotinamide, or carbogen breathing (95% O₂/5% CO₂) on the radiation sensitivity of FSaII murine fibrosarcomas or R3230 AC rat adenocarcinomas was studied. Individually, these treatments increased the tumor cell sensitivity to single dose 10–15 Gy X-irradiation by 1–5 fold on average, as measured by the in vivo/in vitro tumor excision assay. The combination of tumor MTH with nicotinamide or carbogen breathing increased the radiation sensitivity by 3–5 fold in FSaII tumors and 10–30 fold in R3230 tumors with varying levels of statistical significance. Finally, the triple combination of adjuvant MTH, nicotinamide and carbogen breathing increased the radiation-induced cell death in FSaII tumors to a similar extent as the dual combinations of MTH, nicotinamide or heat, carbogen breathing. However, in R3230 AC tumors the triple adjuvant combination significantly increased radiation-induced cell killing compared to all other dual adjuvant treatments (p < 0.04). To interrogate the mechanism by which heating alters tumor physiology, nitric oxide production in tumor and endothelial cells in culture and tumor tissue after heating was studied. Heating caused an increase in nitric oxide production over a 24 h period after treatment. Subsequently, inhibiting the enzymatic production of NO with L-NAME was found to increase heat-induced growth delay of FSaII tumors. The cause and effect of increased nitric oxide production and the response of the tumor vasculature to heat are discussed in the context of the tumor radiosensitization achieved by heating, carbogen breathing and nicotinamide.     

The Anti-Tumor Effect of Interleukin-12 is Enhanced by Mild (Fever-Range) Thermal Therapy

The cytokine interleukin 12 (IL-12) has resulted in notable anti-tumor activity in animal models and in patients and as a result there is considerable interest in learning how to maximize its therapeutic potential while at the same time reducing its known toxic side effects. Strategies which could maintain its effectiveness while permitting reduced dosage could be especially valuable. In this study we used BALB/c mice bearing CT26 tumors as a model for testing whether combining murine IL-12 with a mild (fever range) whole body hyperthermia protocol could result in such a strategy. Our data revealed that 100 ng of IL-12/mouse/day used in combination with FR-WBH was as effective as one in which 300 ng of IL-12/mouse/day was used alone. Importantly, the mice receiving the combination treatment exhibited fewer treatment related toxicities compared to those that received high dose IL-12 alone. Initiation of the IL-12 treatment immediately after FR-WBH induced the greatest anti-tumor effect. This effect does not appear to depend on differences in IL-12-induced IFN-γ, but may involve production of nitric oxide (NO), since treatment of mice with a NOS inhibitor, N^G-monomethyl-l-arginine (l-NMA), abolishes the additive anti-tumor effect of the combination treatment. Collectively, these data suggest that modification of physiological parameters in the host by mild fever-like thermal stimuli may be an effective and feasible adjuvant for cytokine-based immunotherapeutic strategies.