Cold-induced vasodilatation response at different water bath temperatures in monkeys.

The response of cold-induced vasodilatation (CIVD) at different water bath temperatures was studied in 20 monkeys (3.5 kg) in a conscious state in a thermoneutral room. The animals were controlled by seating in a monkey chair, and the right hind limb up to 7.5 cm from the heel was immersed in a water bath for 60 min. Four series of experiments were conducted at water bath temperatures of 0 degrees, 4 degrees, 8 degrees, and 12 degrees C, respectively, at weekly intervals and the skin temperatures were measured from three sites in the foot. Marked CIVD response was noted from the dorsum and, to a lesser extent, from the sole of the foot, but no response was seen from the tip of the middle toe at 0 degrees, 4 degrees, and 8 degrees C water bath temperatures. The pattern of CIVD response at 4 degrees C was identical to that of 0 degrees C, but the response at 8 degrees C was poor and was absent at 12 degrees C. Three patterns of CIVD--such as hunting, proportional control, and slow, steady, and continuous rewarming--was observed. However, 15% of the animals did not exhibit any CIVD. The observations show that the CIVD response of monkeys is remarkably similar to that of man.     

Reproducibility and reliability of fingerprint microfeatures: Effect of immersing hand in water at different temperatures

Poroscopy is the specialized study of sweat pores found on the papillary ridges of the skin. However, the science of poroscopy is not being used to its full potential. The present study was conducted with the goal to assess the effect of immersing hand in water at various temperatures i.e., room temperature (20–30 °C), hot temperature (40–50 °C), and cold temperature (0–10 °C), for 1, 5 and 10 min, on the reproducibility of pore microfeatures namely, area, inter-distance, and angle, in an attempt to demonstrate their reliability in fingerprint matching. As far as the authors are aware, no prior research has attempted to evaluate the impact of immersing hand in water, at different temperatures, on the reproducibility of third level details. Statistical analysis of data revealed that pore inter-distance and angle were reproducible in nature thereby, highlighting their significance in fingerprint matching.     

Diffusion of bromide,iodide and thallium ions at various temperatures

Self-diffusion of bromide, iodide and thallium ions has been studied in NH₄Br, NaI and Tl₂SO₄ respectively over a temperature range of 25–50°C using agar gel medium. Activation energy for the process of diffusion in the above systems is computed from the experimental and theoretical diffusion coefficient data obtained by the zone-diffusion technique and Onsager's equation respectively. A comparison of theoretical and experimental activation energies shows a good agreement in the cases of iodide and thallium ions while the experimental activation energy is found to be lower than theoretical in the case of bromide ions.     

Study of charge transport mechanisms in 125I-induced DNA damage at various temperatures

Abstract

Purpose: Iodine-125 decay induces localized DNA damage by three major mechanisms: (1) Direct damage by the emitted Auger electrons, (2) indirect damage by diffusible free radicals, and (3) charge neutralization of the residual, highly positively charged, tellurium daughter atom by stripping electrons from neighboring residues. The charge neutralization mechanism of ¹²⁵I-induced DNA damage is poorly understood. Charge transport along a DNA molecules can occur by either a hopping mechanism initiated by charge injection into DNA and propagated by charge migration through DNA bases along the DNA length, or by a tunneling mechanism in which charge transfers directly from a donor to an acceptor residue. In the first case additional damage in DNA nucleotides can be inflicted by the traveling charge; therefore, it is important to learn if charge hopping plays a role in ¹²⁵I-decay-induced DNA damage. In our previous work, we determined that at 193K the charge hopping mechanism was not an appreciable component of the mechanism of ¹²⁵I-induced DNA damage. However, the question whether this is also the case at higher temperatures remained open.

Methods: In the current study we used a well-known chemical barrier for charge hopping, 8-oxo-7, 8,-dihydroguanine (8-oxo-G), to assess the role of this mechanism in ¹²⁵I-decay-induced DNA damage at the following temperatures: 198, 253, 277 and 298 K.

Results: We found that varying the temperature had little effect on the distribution of ¹²⁵I-induced DNA breaks, as well as on the breaks found at the 8-oxo-G probe both with and without piperidine treatment.

Conclusions: We thus conclude that charge transport by the hopping mechanism is not a major factor in ¹²⁵I-decay-induced DNA damage at biologically relevant temperatures.     

不同复温方式对犬腹部开放伤合并海水浸泡救治时血流动力学的影响

目的 探讨不同复温方式对犬腹部开放伤合并海水浸泡救治时血流动力学的影响。方法 成年杂种犬30只制作成腹部开放伤动物模型,伤后均浸泡人工海水中,2h后打捞出水,随机分为3组。自然复温组(n=10)：将动物移至温暖环境,靠机体自身产热自发复温;体表复温组(n=10)：用电热毯体表加温;体中心复温组(n=10)：1／3张盐水42℃水浴20min后,腹腔用1／2张盐水持续灌洗2h。观察不同复温方式对犬腹部开放伤合并海水浸泡救治时体温、心率、平均动脉压、中心静脉压和心输出量的影响。结果 自然复温组复温效果不满意,救治6h后体温34．8℃,未恢复正常体温,血压提升困难、心动过速、心输出量降低。体表复温组复温效果优于前组,6h后体温36．9℃,接近致伤前体温,但血压、心率和心输出量也出现同前组类似的表现,只是程度较轻。体中心复温组复温效果满意,救治后4h体温、平均动脉压、中心静脉压和心输出量基本恢复正常。结论 腹部开放伤海水浸泡后体温过低的救治时最好采用体中心复温方式。     

磁处理矿泉水浴对飞行人员血液流变性的影响

磁处理矿泉水有多种治疗作用 ,自1998年以来 ,我们观察了磁处理矿泉水浴对飞行人员血液流变性的影响 ,报告如下。一、对象与方法1.对象 :健康飞行人员 112例 ,年龄 2 5～ 46岁 ;飞行时间 180～ 410 0 h,平均 (846 .32± 95 .16 ) h;飞行机种有歼 - 8(4 2例 )、歼 - 7(38例 )、强 - 5 (2 8例 )和轰 - 6 (14例 ) ,全部为男性。2 .方法 :按随机数字表法将受试者分为磁处理组与对照组 ,每组 5 6例。两组年龄、机种、飞行时间、体重指数及血液流变学各项指标等差异均无显著性意义 (P>0 .0 5 ) ,具有可比性。磁处理组施以磁处理矿泉浴 ,将四块 10…     

Accidental hypothermia: an experimental study of inhalation rewarming.

Inhalation rewarming of hypothermic humans with heated, humidified oxygen was compared to rewarming by immersion in a hot bath. In 10 subjects cooled to approximately 35 degrees C core temperature, there was no significant difference in the amount of temperature "afterdrop" with the two rewarming procedures. Inhalation rewarming provided rapid commencement of increase in tympanic and esophageal temperatures, indicating effective rewarming of critical core regions, especially heart and brain. This method of core rewarming avoids the physiological hazards associated with the peripheral vasodilation which accompanies external rewarming. Moverover the simplicity of application of this method suggests its greater use in both first-aid and hospital treatment of accidental hypothermia.     

The effect of exercise at various temperatures on salivary levels of immunoglobulin A.

The purpose of this investigation was to determine the effect of ambient temperature on the salivary immunoglobulin A (s-IgA) response to submaximal exercise. Nine adult males (x age +/- SD = 22 +/- 2 yrs) volunteered to perform an incremental treadmill test to exhaustion for the determination of VO2max and three 30-minute treadmill runs at 80% VO2max in an environmental chamber at temperatures of approximately 6, 19 and 34 degrees C. Saliva samples were collected prior to each submaximal workbout as well as immediately and 1 hr post-exercise. A 2 within subjects factors (temperature, sample time) repeated measures ANOVA indicated no significant interaction or main effects for sampling time or temperature. The results of this study indicated that 30 minutes of non-competitive exercise at temperatures ranging from 6 to 34 degrees C had no effect on s-IgA. These findings suggest that moderate intensity exercises at a wide range of ambient temperatures does not increase the susceptibility to upper respiratory infection by decreasing s-IgA.     

不同复温方法对兔低温复温时血清肌酸激酶与脂质过氧化物含量的影响

目的：观察三种复温方法对体温过低兔的效果及低温复温时血清肌酸激酶（ＣＫ）和脂质过氧化物（ＬＰＯ）含量的影响，同时探讨电磁局部高热在复温中的应用价值。方法：随机选择２８只家兔浸于冷水中使其平均直肠温度降至２５．６℃，随后以三种不同方法复温至直肠温度３５℃。结果：复温方法平均耗时为：温水浴法７５分钟，电磁局部高温法８９分钟，自然复温法４７１分钟；血清ＣＫ、ＬＰＯ含量在低体温期增加，复温后上升更加明显。结论：电磁局部高温法是一种简便、快速的复温方法；血清ＣＫ、ＬＰＯ的增加说明体温过低对组织有一定损伤，表现为组织细胞的抗氧化能力减弱。     

Treatment of frostbite with i.v. streptokinase: an experimental study in rabbits

Experiments were conducted in 32 rabbits to determine whether treatment with IV streptokinase can effectively limit the extent of tissue damage associated with frostbite injury of the hind limbs. Other variables studied were the temperature of the tissue during freezing, the time taken to rewarm the exposed limbs, and the delay between the initiation of treatment with streptokinase and cessation of freezing. A control group of 16 rabbits was not given streptokinase. The extent of tissue damage was estimated by sequential radionuclide perfusion scans of the exposed limbs. This estimate was based on the proportional loss of tissue perfusion on subsequent twice-weekly nuclear scans in comparison with that shown by scans performed immediately after thawing. Pathologic changes in exposed tissues were studied by histology. Streptokinase treatment and rapid rewarming both resulted in less tissue damage at all freezing temperatures. Streptokinase was most beneficial when given 12 hr after freezing, but was effective even when treatment was delayed up to 48 hr.     

Assessment of tissue viability after frostbite injury by technetium-99m-sestamibi scintigraphy in an experimental rabbit model

Frostbite causes injury to the tissue by direct ice-crystal formation at the cellular level with cellular dehydration and microvascular occlusion. Muscle that initially appears viable on reperfusion may subsequently become necrotic because of microcirculatory collapse. Since muscle is a sensitive tissue in frostbite injury, we used technetium-99m-sestamibi limb scintigraphy to assess tissue viability in an experimental rabbit model. Twelve rabbits were used for this investigation. The right hind limb of the rabbits was immersed to the ankle joint in a container filled with 90% ethanol at -25 degrees C for 10 min. Frostbitten limbs were allowed to thaw in air at room temperature. Imaging and pathological examination of the affected limbs were performed 2 h, 24 h, 48 h and 72 h after freezing. In 2-h images, initial hypoperfusion was seen that corresponded to circulatory collapse. In 24-h images, there was hyperperfusion (so-called period of temporary reperfusion), corresponding to circulatory restoration. In 48-h images, a second hypoperfusion corresponded to viable but ischaemic tissue. In 72-h images, there was non-perfusion of the limb that correlated with the pathologically determined diagnosis of necrosis. All scintigraphic patterns correlated with pathological findings. We suggest that these scintigraphic patterns in soft tissue may be helpful in distinguishing between frank infarction and reversible ischemia and therefore may be useful in selecting early therapeutic or surgical interventions to salvage bone and soft tissue. Further studies are needed to show the usefulness of 99mTc sestamibi scintigraphy in clinical frostbite cases.     

Assessment of tissue viability after frostbite injury by technetium-99m-sestamibi scintigraphy in an experimental rabbit model

Frostbite causes injury to the tissue by direct ice-crystal formation at the cellular level with cellular dehydration and microvascular occlusion. Muscle that initially appears viable on reperfusion may subsequently become necrotic because of microcirculatory collapse. Since muscle is a sensitive tissue in frostbite injury, we used technetium-99m-sestamibi limb scintigraphy to assess tissue viability in an experimental rabbit model. Twelve rabbits were used for this investigation. The right hind limb of the rabbits was immersed to the ankle joint in a container filled with 90% ethanol at –25°C for 10 min. Frostbitten limbs were allowed to thaw in air at room temperature. Imaging and pathological examination of the affected limbs were performed 2 h, 24 h, 48 h and 72 h after freezing. In 2-h images, initial hypoperfusion was seen that corresponded to circulatory collapse. In 24-h images, there was hyperperfusion (so-called period of temporary reperfusion), corresponding to circulatory restoration. In 48-h images, a second hypoperfusion corresponded to viable but ischaemic tissue. In 72-h images, there was non-perfusion of the limb that correlated with the pathologically determined diagnosis of necrosis. All scintigraphic patterns correlated with pathological findings. We suggest that these scintigraphic patterns in soft tissue may be helpful in distinguishing between frank infarction and reversible ischemia and therefore may be useful in selecting early therapeutic or surgical interventions to salvage bone and soft tissue. Further studies are needed to show the usefulness of ^99mTc sestamibi scintigraphy in clinical frostbite cases. Received 1 April 1999 and in revised form 4 August 1999     

Metabolic costs and heart rate responses to treadmill walking in water at different depths and temperatures

Treadmill walking/jogging in water is a potentially useful therapeutic modality. Since energy costs of this activity are unknown, we compared oxygen consumption (VO2) of treadmill walking/jogging in water to a dry treadmill at speeds of 40.23 to 160.9 meters/min (m/m) in 13.4 m/m increments in 11 subjects. At speeds greater than or equal to 53.6 m/m, ankle depth, below knee, midthigh, and waist depth walking/jogging in water significantly elevated VO2 and heart rate (HR) above dry treadmill walking (P less than 0.05). At speeds greater than or equal to 134.1 m/m, VO2 of waist depth jogging was not significantly greater than dry jogging. These findings showed no gender specificity. Treadmill walking/jogging in waist depth water at temperatures of 30.5 degrees C and 36.1 degrees C was compared to dry treadmill walking in five subjects. The rate of increase of HR compared to VO2 was significantly greater at 30.5 degrees C than dry walking, and greater at 36.1 degrees C than 30.5 degrees C (P less than 0.05). Treadmill walking in water can double the oxygen cost of movement depending on the depth and speed, and the response to increasing speed is nonlinear. Water temperature affects the relationship of HR to VO2 at waist depth, suggesting that water temperature can add a significant thermal load to the cardiovascular system. Metabolic and cardiovascular demands of treadmill walking/jogging in water must be considered when using this modality since greater external work results at much lower speeds than on land.     

Assessment of tissue viability in frostbite by 99Tcm-HDP scintigraphy: an experimental study in New Zealand white rabbits.

Since the appearance of superficial tissue is often an unreliable indicator of deep tissue viability in cases of frostbite, radionuclide scintigraphy with 99Tcm-disodium oxidronate (HDP) was used to assess changes in tissue viability after experimental freezing and thawing of the rabbit ear. One shaved ear, left or right, of each of eight New Zealand white rabbits was frozen with a glass bottle (diameter of bottom 2 cm) filled with liquid nitrogen (-180 degrees C) for 5 min under Ketalar-Rompun anesthesia, the other ear serving as a control. Radionuclide scintigraphy was performed by giving a bolus intravenous injection of 130-170 MBq (3.5-4.5 mCi) 99Tcm-HDP. Radionuclide imaging was used to follow the development of the demarcation line. Scintigraphy was performed 2 h after frostbite and then after 24 h, 48 h, 1 week and 3 weeks. The frostbitten area seemed macroscopically to be warm and swollen immediately after the induction of frostbite. Scintigraphy showed the frostbitten area to be much warmer than the surrounding tissue for the first week and it was not until after that the first cold spots appeared in the middle of the frostbitten area. The necrotic and vital tissue could easily be distinguished after 3 weeks.     

Immersion of distal arms and legs in warm water (AVA rewarming) effectively rewarms mildly hypothermic humans

INTRODUCTION: Active rewarming of hypothermic victims for field use, and where transport to medical facilities is impossible, might be the only way to restore deep body temperature. In active rewarming in warm water, there has been a controversy concerning whether arms and legs should be immersed in the water or left out. Further, it has been suggested in the Royal Danish Navy treatment regime, that immersion of hands, forearms, feet, and lower legs alone might accomplish rapid rates of rewarming (AVA rewarming). METHODS: On three occasions, six subjects (one female) were cooled in 8 degrees C water, to an esophageal temperature of 34.3+/-0.8 (+/-SD) degrees C. After cooling the subjects were warmed by shivering heat production alone, or by immersing the distal extremities (hands, forearms, feet and lower legs) in either 42 degrees C or 45 degrees C water. RESULTS: The post cooling afterdrop in esophageal temperature was decreased by both 42 degrees C and 45 degrees C water immersion (0.4+/-0.2 degrees C) compared with the shivering alone procedure (0.6+/-0.4 degrees C; p < 0.05). The subsequent rate of rewarming was significantly greater with 45 degrees C water immersion (9.9+/-3.2 degrees C x h(-1)) than both 42 degrees C water immersion (6.1+/-1.2 degrees C x h(-1)) and shivering alone (3.4+/-1.5 degrees C x h(-1); p < 0.05). CONCLUSION: The extremity rewarming procedure was experienced by the subjects as the most comfortable as the rapid rise in deep body temperature shortened the period of shivering. During the extremity rewarming procedures the rectal temperature lagged considerably behind the esophageal and aural canal (via indwelling thermocouple) temperatures. Thus large gradients may still exist between body compartments even though the heart is warmed.     

Angiography in the diagnosis and therapy of frostbite.

Five patients with frostbite injury were studied by selective angiography and treated by selective intra-arterial application of reserpine with follow-up angiography two days later. Control angiograms showed various degrees of vascular spasm as well as organic stenosis and occlusion. Intra-arterial reserpine produced dramatic subsiding of vasospasm, as evidenced by angiography and relief of clinical symptoms. Complete healing without tissue loss occurred in 4 patients. Amputation was necessary in one case, due at least in part to pre-existing peripheral atherosclerotic disease. Selective angiography was found to contribute significantly to both the diagnosis and therapy of frostbite injury.