Exercise pretraining protects against cerebral ischaemia induced by heat stroke in rats

Background

In the rat brain, heat‐stroke‐induced damage to cerebral neurons is attenuated through heat‐shock‐induced overexpression of heat‐shock protein 72 (HSP72).

Objective

To ascertain whether progressive exercise preconditioning induces HSP72 expression in the rat brain and prevents heat‐stroke‐induced cerebral ischaemia and injury.

Methods

Male Wistar rats were randomly assigned to either a sedentary group or an exercise group. Those in the exercise group progressively ran on a treadmill 5 days/week, for 30–60 min/day at an intensity of 20–30 m/min for 3 weeks. The effects of heat stroke on mean arterial pressure, cerebral blood flow, brain ischaemia markers (glutamate, lactate/pyruvate ratio and nitric oxide), a cerebral injury marker (glycerol) and brain neuronal damage score in the preconditioned animals were compared with effects in unexercised controls. Heat stroke was induced by exposing urethane‐anaesthetised animals to a temperature of 43°C for 55 min, which caused the body temperature to reach 42°C.

Results

Three weeks of progressive exercise pretreatment induced HSP72 preconditioning in the brain and conferred significant protection against heat‐stroke‐induced hyperthermia, arterial hypotension, cerebral ischaemia and neuronal damage; it also prolonged survival.

Conclusions

Exercise for 3 weeks can improve heat tolerance as well as attenuate heat‐stroke‐induced cerebral ischaemia in rats. The maintenance of mean arterial pressure and cerebral blood flow at appropriate levels in the rat brain may be related to overexpression of HSP72.     

胸腹部孤立性纤维瘤的MSCT表现

目的总结分析胸腹腔孤立性纤维瘤的CT表现及临床、病理特征,旨在提高对本病的认识。方法所有患者均有完整的平扫和增强CT以及病理和免疫组化检查资料,分析本病的CT表现并与病理对照。结果 9例孤立性纤维瘤(SFT)中,发生在胸腔6例,腹、盆腔3例。9例肿瘤直径均在5cm以上,其中2例发生在胸腔者最大径超过10cm,2例可见条片状、点状钙化,4例平扫密度均匀。增强后所有病例不均匀强化,其内有条状、小片状坏死区,实性部分轻中度强化,尤其在静脉期表现更明显,呈"地图样"强化,3例动脉期可见较多血管影。结论孤立性纤维瘤的CT表现具有一定特征性,仔细观察、分析可达到准确诊断。     

Fluid replacement during and after exercise in the heat

This study sought to determine whether ad libitum drinking of a carbohydrate-electrolyte (CE) beverage would minimize the physiological disturbances associated with prolonged (3 h) continuous exercise in the heat (Tdb = 31.5 degrees C, percent RH = 22.3). Seven male subjects performed two bouts of cycle exercise (60% VO2max) drinking either a CE beverage (4.85% polycose, 2.65% fructose) or distilled water. Subjects continued to drink ad libitum for 3 h during recovery in the heat. No significant differences were observed between drinks for rectal temperature, heart rate, or sweat rate during exercise. Subjects tended to drink more (P less than 0.0565) water than the CE beverage during exercise, but plasma volume (percent PV) decreased less (P less than 0.0253) and plasma [( glucose], P less than 0.0001 and [K+], P less than 0.0047) were higher when subjects drank the CE solution. At the end of exercise, plasma osmolality and [Na+] were also higher (P less than 0.05) when subjects drank the CE beverage rather than water. Rating of perceived exertion was higher (P less than 0.0001) when drinking water. In recovery, ingesting the CE beverage, 1) subjects drank more (P less than 0.0012); 2) plasma volume increased to a higher level (P less than 0.0017); 3) plasma osmolality (P less than 0.0001), [Na+] (P less than 0.0001), glucose (P less than 0.0001), and [K+] (P less than 0.0015) were greater; and 4) body weight increased more (P less than 0.0422) than when water was ingested. Thus, in terms of minimizing physiological disturbances, ad libitum drinking of the CE beverage was as effective as drinking water during exercise but was more effective in recovery.     

A model of the peritoneal cavity for use in internal dosimetry

Several therapeutic and diagnostic techniques involve injection of radioactive material into the peritoneal cavity. Estimation of the radiation dose to the surface of the peritoneum or to surrounding organs is hampered by the lack of a suitable source region in the phantom commonly used for such calculations. We have modified the Fisher-Snyder phantom to include a region representing the peritoneal cavity which may be employed to estimate such radiation doses. A geometric model is described which is coordinated with the existing organ regions in the phantom. Specific absorbed fractions (derived by Monte Carlo techniques) for photon emissions originating within the cavity are listed. Photon S-values for several radionuclides which have been administered intraperitoneally are shown. Dose conversion factors for electrons irradiating the peritoneal cavity wall, from either a thin plane or volume source of activity within the cavity, are also given for several nuclides.     

穿心莲内酯对小鼠放射性肺损伤的防护作用

目的 观察穿心莲内酯对C57BL/6小鼠放射性肺损伤的保护效应。方法 将80只C57BL小鼠完全随机分为0.9% 氯化钠溶液组（空白对照组）、穿心莲内酯组（单纯给药组）、放射+0.9%氯化钠溶液组（单纯照射组）和放射+穿心莲内酯组（联合组）,每组20只。照射前单纯给药组和联合组用穿心莲内酯 20 mg·kg^-1·d^-1灌胃,空白对照组和单纯照射组用等体积0.9%氯化钠溶液灌胃,连续灌胃30 d。采用6 MV高能X射线直线加速器单次15 Gy照射,建立小鼠全肺放射性肺损伤模型。取小鼠肺组织HE染色、Masson染色进行组织病理学观察;采用 ELISA 法检测小鼠血清转化生长因子β1（TGF-β1）、肿瘤坏死因子α（TNF-α）;紫外分光光度计检测肺组织丙二醛（MDA）含量、超氧化物歧化酶（SOD）活力和羟脯氨酸（Hyp）含量。结果 联合组小鼠肺组织损伤程度较单纯照射组小鼠明显减轻,其肺系数、肺组织MDA含量、羟脯氨酸含量以及血清 TGF-β1、TNF-α表达水平虽然略高于空白对照组,但低于单纯照射组差异有统计学意义（t_肺系数=1,60, t_MDA=7.06, t_羟脯氨酸=17.44, t_TGF-β1=16.67, t _TNF-α=14.03,P <0.05）;联合组小鼠血清SOD活力明显高于单纯照射组（t=60.81,P<0.05）,但低于空白对照组和单纯给药组;单纯给药组小鼠各项检测指标与空白对照组相比,差异均无统计学意义。结论 穿心莲内酯可有效减轻小鼠的放射性肺损伤,且对小鼠肺组织无明显毒性。     

Assessment of bone mineral content in the internal bone volume

A method for assessing values related to bone density and mass is described. Mean attenuation and pixel area are measured in pixels selected on the basis of CT units. The method is to a large extent computerized and not dependent on manual positioning or outlining of a region of interest. Because it is not dependent on a comparatively large volume of homogeneous bone it can be used to make assessments even in very heterogeneous bones including cortical bone. The method is adaptable for measurement in all parts of the skeleton and values related to both bone density (DRV) and bone mass (MRV) are derived. The measurements in the femoral condyles were shown to have a precision of approximately 0.25 to 0.30 Z-score units (standard deviation of the measurements expressed in Z-score units). The agreement between chemically analyzed calcium density (weight of calcium per volume) and DRV was little less than 0.50 Z-scores and 0.30 Z-scores for the chemically determined calcium mass and the MRV. The agreement with mechanical bone strength was 0.78 Z-scores for DRV and 0.64 for the MRV. Altering scan parameters or measuring approaches gave systematic differences in measurements. There were, however, good linear correlations between the measurements which show that these different measuring approaches essentially gave identical measurements.     

Lateral intrathoracic meningocele with spontaneous rupture into the pleural cavity diagnosed with RIHSA myelography

Summary A patient with a lateral intrathoracic meningocele was examined with radioisotope myelography after lumbar intrathecal injection of RIHSA. The diagnosis of a meningocele could be established from the passage of RIHSA into the lesion. The meningocele had ruptured spontaneously into the pleural cavity, as evidenced by RIHSA appearing in the pleural fluid. The activity was recorded by scintigraphy and by direct measurement of samples of pleural fluid. The value of radioisotope myelography in diagnosis and differential diagnosis is emphasised.

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Laterale intrathorakale Meningocele mit spontaner Ruptur in den Pleura-Raum, diagnostiziert mit der RISA Myelographie

Zusammenfassung Bei einem Patienten mit einer lateralen intrathorakalen Meningocele wurde eine Isotopen-Myelographie nach lumbaler Injektion von RISA durchgeführt. Dabei konnte die Diagnose einer Meningocele exakt gestellt werden. Sie war spontan in den Pleura-Raum rupturiert. RISA trat in der Pleuraflüssigkeit auf.

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Méningocèle intra-thoracique latéral avec rupture spontanée dans la cavile pleurale diagnostiquee par la myélographique isotopique

Résumé L'auteur rapporte le cas d'un malade porteur d'un méningocèle intra-thoracique latéral quifut examiné par myélographie isotopique après injection lombaire intra-arachnoïdienne de Rhisa. Le diagnostic de méningocèle put être posé par le passage de Rhisa dans la lésion. Le méningocèle s'était rompu spontanément dans la cavité pleurale ainsi qu'en témoignait la présence de Rhisa dans le liquide pleural. L'activité fut enregistrée par la scintigraphie et par des mesures directes sur des échantillons de liquide pleural. L'auteur souligne la valeur de la myélographie isotopique dans le diagnostic différentiel.

     

Nitric oxide protects against contrast media-increased pulmonary vascular permeability in rats

RATIONALE AND OBJECTIVES: Nitric oxide (NO) regulation of endothelial function is involved in the development of acute lung injury. The role of NO in contrast media-induced increases in pulmonary vascular permeability was investigated in a rat model. METHODS: Nonionic (iohexol) and ionic (ioxaglate) contrast media were intravenously injected at 1.5 mL/min in rats. Pulmonary vascular permeability was evaluated by measuring the amount of Evans blue dye uptake as a quantitative marker of albumin extravasation in lung tissue. RESULTS: Intravenous injections of contrast media at doses of 4 and 6 g I/kg induced a dose-dependent increase in pulmonary vascular permeability. L-Arginine (an NO synthase substrate) and N(G)-nitro-L-arginine (L-NNA) (an NO synthase inhibitor) prevented and aggravated, respectively, the increase in pulmonary vascular permeability induced by the contrast medium. An aggravating action of L-NNA was confirmed by morphological and histological observations, this action being blocked by L-arginine (300 mg/kg) but not by D-arginine. Isosorbide dinitrate (1-20 mg/kg), an NO donor, had a dose-dependent protective effect on ioxaglate-increased vascular permeability. CONCLUSIONS: Our experimental findings suggest that contrast media at high doses produce pulmonary edema by inhibiting endothelial NO production, and nitrovasodilators protect against this adverse effect in rats.     

Icariin protects against radiation-induced mortality and damage in vitro and in vivo

Abstract

Purpose: The present study aimed to investigate the potential protective effects of icariin both in vivo and in vitro, an active flavonoid glucoside derived from medicinal herb Epimedium, and its possible mechanisms against radiation-induced injury.

Methods: Male C57BL/6 mice were exposed to lethal dose (7?Gy) or sub-lethal dose (4?Gy) of whole body radiation by X-ray at a dose rate of ～0.55?Gy/min, and icariin was given three times at 24?h and 30?min before and 24?h after the irradiation. After irradiation, hematological, biochemical, and histological evaluations were performed. We further determined the effect of icariin on radiation-induced cytotoxicity and changes in apoptosis-related protein expression.

Results: Icariin enhanced the 30-day survival rates (20 and 40?mg/kg) in a dose-dependent manner, and protected the radiosensitive organs such as intestine and testis from the radiation damages. Moreover, hematopoietic damage by radiation was significantly decreased in icariin-treated mice as demonstrated by the increases in number of peripheral blood cells, bone marrow cells (1.7-fold), and spleen colony forming units (1.7-fold). In addition, icariin decreased the radiation-induced oxidative stress by modulating endogenous antioxidant levels. Subsequent in vitro studies showed that icariin effectively increased cell viability (1.4-fold) and suppressed the expression of apoptosis-related proteins after irradiation.

Conclusion: These results suggest that icariin has significant protective effects against radiation-induced damages partly through its anti-oxidative and anti-apoptotic properties.     

Fluid within preexisting pulmonary air-spaces: a potential pitfall in the CT differentiation of pleural from parenchymal disease

There have been many reports of the ability of CT to distinguish between parenchymal and pleural disease. The purpose of this report is to describe the appearance of seven cases of intraparenchymal fluid-filled air-spaces (bullae or lung cysts) in which the CT findings may resemble those of pleural disease and, thus, cast doubt on the specificity of the established criteria.     

Fluid replacement during sustained activity in the heat: nutrient solution vs. water

This study examined the thermoregulatory and hydrational status of men during sustained activity in a hot-dry (37 degrees C, 20% rh) environment while they consumed only a nutrient solution (nutrient), or consumed only colored, flavored water (control). Eleven heat acclimated young men attempted 24-h sustained activity experiments. These experiments consisted of alternating 45-min bouts of treadmill walking (410 W, approximately 30% VO2max) and rest (including sedentary activity). Data were analyzed through 13 h (after 13 h subjects began to discontinue testing). No significant differences between trials were observed for metabolic rate, fluid intake, skin or rectal temperature, sweating rate, plasma volume (as indicated by hemoglobin concentration) or plasma glucose concentrations. By the 8th h plasma osmolality was higher and by the 11th h plasma free fatty acids were lower during the nutrient trial compared to the control. In separate experiments with nine different men, the gastric emptying rates of the nutrient solution and water were compared during exercise (55% VO2max) in the heat (35 degrees C, 20% rh). The gastric emptying rates of the nutrient solution and water were similar (approximately 20 ml.min-1). These data indicate that during 13 h of sustained activity in a hot environment, the nutrient solution and water provided similar thermoregulatory and hydrational benefits.     

Combination of estrogen replacement and exercise protects against HDL oxidation in post-menopausal women

The incidence of atherosclerosis and cardiovascular disease (CVD) in women increases following menopause and has been associated with a reduction in circulating estrogen. Increased CVD risk is also perpetuated by sedentary lifestyle. Growing evidence indicates that oxidation of lipoproteins leads to a powerful immune response, disruption of normal lipoprotein function, and deposition of atherosclerotic plaques. For example, once high-density lipoproteins (HDL) are oxidized, they lose the ability to a) participate in reverse transport of cholesterol to the liver, and b) protect low-density lipoproteins (LDL) against oxidation. The purpose of this study was to determine the effects of combining estrogen replacement and exercise upon lipid peroxidation of the HDL fraction (HDL-ox). Blood samples were drawn from 34 post-menopausal women from four groups: women who were not receiving estrogen replacement and who were sedentary (NSD) (n = 9); women who were not receiving estrogen replacement and who were participating in regular exercise (NEX) (n = 8); women who were receiving estrogen replacement and who were sedentary (ESD) (n = 8); and women who were receiving estrogen replacement and who were participating in regular exercise (EEX) (n = 9). Total-HDL cholesterol was significantly higher (p<0.05) in EEX when compared with NEX, NSD, and ESD. HDL-ox was assessed via malondialdehyde (MDA). Mean (+/- SEM) values for HDL MDA expressed in nM are as follows: NSD = 903.3 +/- 118.4; NEX = 1226.7 +/- 247.7; ESD = 876.7 +/- 116.3; EEX = 537.4 +/- 74.8. EEX lipid peroxidation was significantly (p = 0.02) lower than NEX. Lipid peroxidation tended to be lower in EEX than in NSD and ESD (p = 0.07). These data indicate that the combination of estrogen replacement and regular exercise in post-menopausal women may be most effective in reducing oxidation of HDL in vivo.     

螯合剂BPCBG对急性铀中毒大鼠的促排效果及肾损伤的保护作用

目的 探讨螯合剂BPCBG对急性铀中毒大鼠促排作用的量-效和时,效关系以及对铀致肾损伤的保护作用.方法 Sprague-Dawley( SD)雄性大鼠按随机数字表法分为正常对照组、铀中毒组、不同剂量BPCBG组和DTPA-CaNa3组.给药组大鼠于腹腔注射醋酸铀酰(100μg/只)后,立即分别肌肉注射60、120和600μmol/kg BPCBG及120和600μmol/kg DTPA-CaNa3,或于注射醋酸铀酰前0.5和2h、铀中毒后0、0.5、1及2h肌肉注射120 μmol/kg BPCBG,铀中毒组于注射醋酸铀酰后立即注射等体积生理盐水,正常对照组仅注射生理盐水.采用ICP-MS方法检测24 h尿铀排出量和肾、骨中铀蓄积量.大鼠注射醋酸铀酰(500 μg/只)后立即注射600 μmol/kg BPCBG和1200 μmol/kg DTPA-CaNa3,48 h后检测血清肌酐(SCR)与尿素氮(BUN)含量,取一侧肾脏做肾组织病理切片观察.结果 铀中毒后立即注射不同剂量BPCBG(60、120和600 μmoL/kg)使24h尿铀排出量比铀中毒组增加(t =2.22、4.43、5,80,P＜0.05),肾和骨铀蓄积量下降(t.3.33、5.59、4.53,P＜0.01和t=2.15、8.70、9.10,P＜0.05),随给药剂量增加促排效果明显提高.提前0.5h或延迟0.5和1h给予BPCBG,仍有较好的排铀效果(与铀中毒组比较,尿铀排出量:提前0.5 h t=4.34,延迟0.5 ht=3.35,P＜0.05;肾铀蓄积量:t=5.75、7.74、5.87,P＜005:骨铀蓄积量:t=6.43、5.22、2.60,P＜0.05),但随铀中毒和给药间隔时间的延长而下降.BPCBG立即给药能明显减轻铀中毒致肾脏的病理损伤,使SCR及BUN含量降低至正常对照组水平,对铀致肾功能损伤具有保护作用.DTPA-CaNa3虽然能明显降低大鼠肾铀蓄积量(与铀中毒组相比,120和600-μmol/kg,t =2.28、3.35,P＜0.05),但未能显著增加尿铀排出量,骨铀蓄积量还有增加趋势,并且对铀致大鼠肾损伤无保护作用.结论 BPCBG对急性铀中毒大鼠有良好的促排效果与肾脏保护作用,有可能成为一种新型铀促排螯合剂.