Influence of Acute Pain Induced by Activation of Cutaneous Nociceptors on Ventilatory Control

Background: Although many studies show that pain increases breathing, they give little information on the mechanism by which pain interacts with ventilatory control. The authors quantified the effect of experimentally induced acute pain from activation of cutaneous nociceptors on the ventilatory control system.

Methods: In eight volunteers, the influence of pain on various stimuli was assessed: room air breathing, normoxia (end-tidal pressure of carbon dioxide (PETCO2) clamped, normoxic and hyperoxic hypercapnia, acute hypoxia, and sustained hypoxia (duration, 15-18 min; end-tidal pressure of oxygen, approximately 53 mmHg). Noxious stimulation was administered in the form of a 1-Hz electric current applied to the skin over the tibial bone.

Results: While volunteers breathed room air, pain increased ventilation (V with dotI) from 10.9 +/- 1.7 to 12.9 +/- 2.5 l/min sup -1 (P < 0.05) and reduced PETCO2 from 38.3 +/- 2.3 to 36.0 +/- 2.3 mmHg (P < 0.05). The increase in V with dotI due to pain did not differ among the different stimuli. This resulted in a parallel leftward-shift of the V with dotI -carbon dioxide response curve in normoxia and hyperoxia, and in a parallel shift to higher V with dotI levels in acute and sustained hypoxia.     

Systematic Review and Pooled Estimates for the Diagnostic Accuracy of Serological Markers for Intestinal Ischemia

Background  Intestinal ischemia is a potentially catastrophic abdominal emergency that presents a significant diagnostic challenge in the critical care setting. We performed a systematic review of the literature to define the diagnostic accuracy of serological markers of intestinal ischemia. Methods  Observational studies on the performance of markers of intestinal ischemia were identified within the MEDLINE and EMBASE electronic databases. All studies from which it was possible to derive true positive, false positive, false negative, and true negative results were included. A random-effects model was used to calculate the pooled estimates of diagnostic accuracy. Results  A total of 20 articles examining 18 different serological markers were identified that met the inclusion criteria. The global measures of test performance (diagnostic odds ratio and area under the summary receiver operating characteristic curve) for markers investigated in three or more studies were d-lactate (10.75 and 0.86, respectively), glutathione S-transferase (GST; 8.82 and 0.87, respectively), intestinal fatty-acid binding protein (i-FABP; 7.62 and 0.78, respectively), and d-dimer (5.77 and 0.53, respectively). Conclusions  The performance of the currently available serological markers is suboptimal for routine clinical use, but novel markers of intestinal ischemia such as d-lactate, GST, and i-FABP may offer improved diagnostic accuracy. The early diagnosis of intestinal ischemia remains a challenge, and further research is required to identify improved serological markers and to demonstrate their clinical utility in the individual patient.     

Precision of Quantitative Ultrasound Measurement of the Heel Bone and Effects of Ambient Temperature on the Parameters

The goal of this study was to determine the magnitude of measurement error of a quantitative ultrasound (QUS) measurement system of the heel bone in a practical setting and to examine the effects of ambient temperature in the test room on QUS parameters. We assessed the intratest, intertest and interdevice coefficients of variation (CVs) for speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness in vitro using phantoms and in vivo using volunteers. The intratest CV was the smallest and the interdevice CV was the greatest for every QUS parameter. The intertest CVs in vivo were 0.50% for SOS, 2.53% for BUA and 4.38% for stiffness. The standardized precision error (sPE) of stiffness, however, was smaller than those of the other two parameters. The intertest sPEs in vivo of the QUS parameters were 2–3 times greater than that of the spine bone mineral density (BMD) as measured by dual-energy X-ray absorptiometry (DXA). Using an average of duplicate measurements for the representative value of a subject could improve sPE of the QUS parameters to around 2 times greater than that of spine BMD. We examined five phantoms each with the QUS system under the ambient temperature conditions of 10, 20 and 30 °C. The lower the room temperature, the greater the values of all the QUS parameters obtained. We then assessed the effect of the season on the QUS parameters in healthy five women. SOS and stiffness were significantly greater in February (room temperature, 12.6 °C) than in June (22.4 °C) by 0.74% and 3.2% of overall means, respectively, by 10.1% and 4.3% as a standardized difference, or by 0.422 and 0.214 in Z-scores. This difference was likely to be caused by the difference in heel temperature between the seasons. The precision of the QUS system was inferior to that of conventional DXA densitometry. We recommend that institutions using several QUS system devices throughout the year at various locations monitor the precision of each device, make duplicate measurements for a single subject, use the same device for each patient being followed, and control the heel temperature of subjects by keeping the test room temperature constant throughout the year. Received: 15 October 1998 / Accepted: 19 May 1999     

温度对于肌松药的影响

温度的变化会引一系列的生理代谢及器官功能的改变 ,影响肌松药的代谢和时效。全身低温时 ,肌松药在循环和神经肌肉位点之间的移动缓慢 ,起效、恢复延迟 ,肌松药在肝脏肾脏的清除排泌或自身降解受到影响 ,药物的清除半衰期延长 ,神经肌肉传导阻止的时间相应延长。高温时则有药效降低、作用时间缩短的趋势。不同的温度对于不同的肌松药影响的机制、程度不同。     

Proliferation of Pulmonary Artery Smooth Muscle Cells in the Development of Ascites Syndrome in Broilers Induced by Low Ambient Temperature

Pulmonary vascular remodelling, mainly characterized by arterial medial thickening, is an important pathological feature of broiler ascites syndrome (AS). Since vascular smooth muscle cells (VSMC) form the major cellular component of arterial medial layer, we speculate that VSMC proliferation is one of the causes of pulmonary arterial medial thickening in ascitic broilers. Hence, the present study was designed to investigate the role of VSMC proliferation in pulmonary vascular remodelling in development of AS induced by low ambient temperature. Broilers in control group (22 ± 1.5°C) and low temperature group (11 ± 2°C) were sampled every week at 15–50 days of age. Proliferative indexes of VSMC in pulmonary arteries were assessed with proliferating cell nuclear antigen, and the relative medial thickness (RMT) and relative wall area (RWA), as indexes of pulmonary vascular remodelling, were examined by computer‐image analysing system. The results showed that the high incidence (18.75%) of AS was induced by low temperature, and a significantly increased VSMC proliferation was observed in pulmonary arteries in the low temperature group at 22–50 days of age (P < 0.05). In addition, RMT and RWA in pulmonary arteries were significantly elevated in the low temperature group from 36 days of age (P < 0.05), indicating that pulmonary vascular remodelling occurred following VSMC proliferation in AS. Our data suggest that proliferation of VSMC may facilitate pulmonary vascular remodelling and have a pivotal role in AS induced by low ambient temperature.     

Influence of Leukotriene Inhibitor Montelukast on Wound Contraction and Cutaneous Healing Process in Rats

Background  Wound contractures can cause severe deformities and disabilities. Recent studies have suggested that leukotriene receptor antagonists have an inhibitory effect on the healing contraction process. This study aimed to evaluate the influence of the leukotriene inhibitor montelukast on the cutaneous healing process and the wound contraction phenomenon in rats. Methods  For this study, 60 male rats were randomly divided into four groups (MK-7d, SF-7d, MK-14d, and SF-14d) according to the drug given through a rigid orogastric tube (MK group: montelukast 10 mg/kg/day; SF group: normal saline solution) and the day the animals were killed (7d: postoperative day 7; 14d: postoperative day 14). An excisional wound (2 × 2 cm) was created on the dorsum of each rat. The wounds were left open to heal spontaneously and documented by standard digital photographs on different postoperative days. Wound contraction rates were calculated with specific software, and specimens were histologically evaluated using picrosirius red stain. Results were analyzed using the Aspin-Welch, Mann–Whitney, and t tests, assuming a significance level of 5%. Results  The wound contraction rates were similar between the control and study groups (p > 0.05). On postoperative day 7, the wounds showed a marginally significant reduction in collagen maturation in the study group (40.1% ± 6.88% vs 61.2% ± 8.02%; p = 0.0607). On postoperative day 14, this reduction was statistically significant in the MK group (26% ± 5.66% vs 68.3% ± 7.76%; p = 0.0001). Conclusions  Montelukast does not alter the contraction rate of excisional wounds in rats but has a significant and progressive inhibitory effect on collagen maturation. This study was developed by the Post-Graduate Program in Surgery and Plastic and Reconstructive Surgery Unit of Federal University of Paraná, Curitiba, Brazil.     

Influence of Tumor Histology on Preoperative Staging Accuracy of Breast Metastases to the Axilla

Histologic confirmation of axillary nodal metastases preoperatively avoids a sentinel node biopsy and enables a one step surgical procedure. The aim of this study was to establish the local positive predictive value of axillary ultrasound (AUS) and guided needle core biopsy (NCB) in axillary staging of breast cancer, and to identify factors influencing yield. A prospective audit of 142 consecutive patients (screening and symptomatic) presenting from 1st December 2008–31st May 2009 with breast lesions categorized R4–R5, who underwent a preoperative AUS, and proceeded to surgery was undertaken. Ultrasound‐guided NCB was performed on nodes radiologically classified R3–R5. Lymph node size, number, and morphological features were documented. Yield was correlated with tumor size, grade, and histologic type. AUS/NCB was correlated with post surgical pathologic findings to determine sensitivity, specificity, positive and negative predictive value of AUS and NCB. A total of 142 patients underwent surgery, of whom 52 (37%) had lymph node metastases on histology. All had a preoperative AUS, 51 (36%) had abnormal ultrasound findings. 46 (90%) underwent axillary node NCB of which 24 (52%) were positive. The smallest tumor size associated with positive nodes at surgery was 11.5 mm. The sensitivity of AUS was 65%. Specificity was 81%, with a positive predictive value (PPV) of 67% and negative predictive (NPV) value of 80%. Sensitivity of U/S‐guided NCB was 75%, with a specificity of 100%, PPV 100% and NPV 64%. Sensitivity of AUS for lobular carcinoma was 36% versus 76% for all other histologies. Sensitivity of NCB for lobular cancer was 33% versus 79% for all other histologies. The most significant factor producing discordance between preoperative AUS and definitive histologic evidence of lymph node metastasis was tumor type. Accurate preoperative lymph node staging was prejudiced by lobular histology (p < 0.0019).     

温度和二次刺激对中性粒细胞反应能力的影响

目的采用体外模型方法研究中性粒细胞经历体外循环中温度的初始启动作用后,遭遇二次刺激时反应能力的变化。方法抽取60例健康志愿者的血样,提取中性粒细胞,根据体外循环的温度变化,采用随机数字表法随机分为常温、微温、中低温、深低温和复温过热组5组,每组12例。利用聚合酶链式反应（PCR）仪建立温度对中性粒细胞刺激的体外模型,每组内设定5个时间点,分别为T0：体外循环起点,T1：复温起点,T2：复温后0.5 h,T3：复温后1 h,T4：复温后1.5 h。在T2、T3、T4点加入血小板活化因子（PAF）刺激0.5 h,测定膜结合弹性蛋白酶（membrane-bound elastase,MBE）活性,作为中性粒细胞受到二次刺激时的反应能力指标。统计学处理采用SPSS13.0软件进行协方差分析,如果主效应存在差异,则采用Bonferroni法进行两两比较。结果各温度组之间MBE值差异有统计学意义（F=4.372,P=0.002）：常温与微温组之间差异无统计学意义（81.9±4.5 ng/106细胞数vs.76.5±3.6 ng/106细胞数,P=0.134）,但常温和微温组均高于其余各组（P=0.001）,复温过热组高于深低温组（61.2±2.7 ng/106细胞数vs.50.9±3.7 ng/106细胞数,P=0.005）,中低温组（56.4±3.2 ng/106细胞数）与深低温（P=0.107）、复温过热组（P=0.167）差异均无统计学意义。各时间点加入PAF后5组间MBE值差异有统计学意义（F=3.566,P=0.03）：T4〉T2（70.9±2.5 ng/106细胞数vs.59.9±2.3 ng/106细胞数,P=0.027）,T3（65.5±1.8 ng/106细胞数）与T2（P=0.168）、T4时间点（P=0.292）之间差异无统计学意义。结论体外循环中常温、微温、复温过热可增强中性粒细胞对二次刺激的反应能力,促进MBE的释放;复温期间存在中性粒细胞易激惹的时间窗。     

Influence of Shearing on the Circadian Rhythm of Body Temperature in the Sheep

The presence of functional rhythmic variations is a well‐demonstrated phenomenon at all levels of physiological organization and especially in the functioning of the cell components, of tissues and of organic systems. In domestic animals, the body temperature presents spontaneous and regular periodic oscillations over different periods of time, which are the result of complex mechanisms that witness the existence of endogenous and exogenous factors. Taking this knowledge as a starting‐point, the authors studied 12 Comisana breed ewes to observe the influence of shearing on the circadian periodicity of rectal and skin temperature. The obtained results show the transient loss of body temperature rhythm by shearing, with an exogenous component, the shearing itself, and an endogenous component, the modifications of metabolic levels induced by the removal of the fleece, the external insulating layer.     

温度对体外精子活力的影响

将42名生育力男子的精液置于17°～37℃间的4组不同温度下检查精子活力,以探讨温度对体外精子活力的影响。结果表明:温度对精子前向运动和活动精子百分率有显著影响,而前向运动级别比活动精子百分率对温度的敏感性更高。36～37℃精子活力最好。24°～25℃组与36°～37℃组之间,精子前向运动级别(0～Ⅲ级制)和活动精子百分率的差异无统计学意义。低于24℃则活力下降。文章认为精液常规和有关精子活力的检查宜在24℃以上进行,需要发挥精子活力的实验宜在37℃左右进行。     

库血加温输注对术中患者体温的影响

目的探讨库血加温输注对手术患者体温的影响.方法将100例外科手术患者随机分为观察组和对照组,各50例.对照组按常规输血,观察组输血前将库血置37 ℃水浴箱10 min,分别于麻醉前,麻醉后30、60、120 min,术毕,术后30、60 min观察患者腋温和寒战发生情况.结果两组患者麻醉后60 min至术后60 min不同时间腋温比较,差异有显著性意义(均P＜0.01);两组寒战总发生率比较,差异有显著性意义(P＜0.01).结论库血加温输注可以预防患者术中体温下降及寒战的发生,提高患者的手术耐受性.     

The Influence of Reconstruction Kernel on Bone Mineral and Strength Estimates Using Quantitative Computed Tomography and Finite Element Analysis

Quantitative computed tomography has been posed as an alternative imaging modality to investigate osteoporosis. We examined the influence of computed tomography convolution back-projection reconstruction kernels on the analysis of bone quantity and estimated mechanical properties in the proximal femur. Eighteen computed tomography scans of the proximal femur were reconstructed using both a standard smoothing reconstruction kernel and a bone-sharpening reconstruction kernel. Following phantom-based density calibration, we calculated typical bone quantity outcomes of integral volumetric bone mineral density, bone volume, and bone mineral content. Additionally, we performed finite element analysis in a standard sideways fall on the hip loading configuration. Significant differences for all outcome measures, except integral bone volume, were observed between the 2 reconstruction kernels. Volumetric bone mineral density measured using images reconstructed by the standard kernel was significantly lower (6.7%, p?<?0.001) when compared with images reconstructed using the bone-sharpening kernel. Furthermore, the whole-bone stiffness and the failure load measured in images reconstructed by the standard kernel were significantly lower (16.5%, p?<?0.001, and 18.2%, p?<?0.001, respectively) when compared with the image reconstructed by the bone-sharpening kernel. These data suggest that for future quantitative computed tomography studies, a standardized reconstruction kernel will maximize reproducibility, independent of the use of a quantitative calibration phantom.     

The Influence of Tibial Positioning on the Diagnostic Accuracy of Combined Posterior Cruciate Ligament and Posterolateral Rotatory Instability of the Knee

Background

To determine if tibial positioning affects the external rotation of the tibia in a dial test for posterolateral rotatory instability combined with posterior cruciate ligament (PCL) injuries.

Methods

Between April 2007 and October 2007, 16 patients with a PCL tear and posterolateral rotatory instability were diagnosed using a dial test. The thigh-foot angle was measured at both 30° and 90° of knee flexion with an external rotation stress applied to the tibia in 2 different positions (reduction and posterior subluxation). The measurements were performed twice by 2 orthopedic surgeons.

Results

In posterior subluxation, the mean side-to-side difference in the thigh-foot angle was 11.56 ± 3.01° at 30° of knee flexion and 11.88 ± 4.03° at 90° of knee flexion. In the sequential dial test performed with the tibia reduced, the mean side-to-side difference was 15.94 ± 4.17° (p < 0.05) at 30° of knee flexion and 16.88 ± 4.42° (p = 0.001) at 90° of knee flexion. The mean tibial external rotation was 5.31 ± 2.86° and 6.87 ± 3.59° higher in the reduced position than in the posterior subluxation at both 30° and 90° of knee flexion.

Conclusions

In the dial test, reducing the tibia with an anterior force increases the ability of an examiner to detect posterolateral rotary instability of the knee combined with PCL injuries.     

饮用温开水对腋温的影响

目的探讨饮用温开水对腋温的影响及其影响时间。方法对71名（健康成人）和在其中随机抽取的20名受试者分别于饮用50℃、40℃温开水前及饮用后0100、30、40、50min测量腋温。结果71名受试者饮用50℃温开水及20名受试者饮用40℃温开水后0、10、20、30、40min的平均腋温均较饮用前显著升高（均P〈0．05），至50min时体温才接近饮用前（均P〉0．05）；饮用40．℃与50℃温开水后各时段腋温比较，差异无显著性意义（均P〉0．05）。结论饮用温开水后不宜立即测腋温，至少应间隔50min，40℃与50E温开水对腋温影响的差异可忽略。     

饮用温开水对腋温的影响

目的 探讨饮用温开水对腋温的影响及其影响时间.方法 对71名(健康成人)和在其中随机抽取的20名受试者分别于饮用50℃、40℃温开水前及饮用后0、10、20、30、40、50 min测量腋温.结果 71名受试者饮用50℃温开水及20名受试者饮用40℃温开水后0、10、20、30、40 min的平均腋温均较饮用前显著升高(均P＜0.05),至50 min时体温才接近饮用前(均P＞0.05);饮用40℃与50℃温开水后各时段腋温比较,差异无显著性意义(均P＞0.05).结论 饮用温开水后不宜立即测腋温,至少应间隔50 min,40℃与50℃温开水对腋温影响的差异可忽略.