Effect of prior exposure to hand-transmitted vibration on cold response of digital arteries

Objectives To investigate whether prior exposure to hand-transmitted vibration on the day of a cold provocation test affects the cold response of digital arteries. Methods Each of ten healthy men attended two experimental sessions in which their right hands were exposed for 60 min to either contact force alone (5 N) or a combination of contact force (5 N) and 125-Hz vertical vibration with an acceleration magnitude of 64 m s⁻² r.m.s. (unweighted). Finger systolic blood pressure (FSBP) during local cooling to 10°C was measured in the second right finger (exposed hand) and the second left finger (unexposed hand) before exposure and at 30 and 70 min after the end of both exposure conditions. Results Analysis of repeated measures of FSBP during local cooling by means of an autoregressive model revealed no significant difference in cold-induced vasoconstriction of the digital arteries between exposure to contact force alone and combined exposure to contact force and vibration. There were no significant changes in the cold response of digital arteries over time in either the right or the left hand after exposure of the right hand to either the contact force alone or the combined contact force and vibration. Conclusions The results of this experimental study of the influence of prior vibration exposure on the cold test results suggest that in healthy men recent exposure to contact force and moderate levels of hand-transmitted vibration does not affect the response of finger circulation to cold provocation. These findings may be of practical importance for the definition of test conditions in the field, especially the length of time required between the last occupational exposure to tool vibration and the commencement of objective vascular testing.     

常温流动牙胶应用于根尖诱导成形术后根管充填

目的: 评价常温流动牙胶应用于年轻恒牙根尖诱导成形术后根管充填的临床效果。方法: 选择2020年4—10月在北京大学口腔医院门诊部儿童口腔科就诊因年轻恒牙牙髓坏死或根尖周病变经过完善的根尖诱导成形术治疗的病例,共收集到病例90例,随机分为两组,试验组和对照组各45例。试验组采用常温流动牙胶充填系统,对照组采用热牙胶充填系统进行根管充填,记录每根管的根管充填时间,由患儿监护人填写VAS(visual analog scales)视觉模拟评分量表评估治疗疼痛程度,术后即刻拍摄X线片,评价根管充填效果,并分别对根管下段、中段、上段的三维充填严密程度进行分析,术后6个月、12个月进行临床检查并拍摄X线片判断治疗成功率。结果: 试验组平均每根管充填时间明显低于对照组,分别为51 s和 74 s,组间比较差异有统计学意义(P<0.05);两组疼痛发生率分别为26.67%和40.00%;试验组和对照组的根管充填恰填且三维充填严密率分别为71.11%和60.00%;根尖1/3区域三维充填严密率为86.67%和66.67%,组间差异有统计学意义(P<0.05),根中1/3及根上1/3根管充填的三维严密性两组间差异无统计学意义;1年复查期内两组均未见根尖病变。结论: 常温流动牙胶应用于年轻恒牙根尖诱导成形后根管充填可取得良好的根管充填效果,根尖1/3区域的根管充填效果优于热牙胶,常温流动牙胶能够缩短临床治疗时间,改善患儿的舒适度。     

Gold 195m in the assessment of the cold pressor test by first pass radionuclide ventriculography

First pass radionuclide ventriculography was performed withgold 195m in a sequential evaluation of left ventricular ejectionfraction during cold pressor stimulation. We studied 10 normalcontrols, 10 patients with angina pectoris who had proven coronaryartery disease and normal left ventricular function during contrastangiography and 10 patients with dilated cardiomyopathy withnormal coronary arteries and impaired left ventricular functionat contrast angiography. Mean resting ejection fraction was similar in controls and patientswith coronary heart disease (57 ± 2 vs 58 ± 3)but was significantly lower in the cardiomyopathic subjects(27 ± 4, P < 0.001). After 30 seconds cold pressorstimulation, mean left ventricular ejection fraction fell inthe normal controls (57 ± 2 to 52 ± 2, P <0.05)but was unchanged in those with coronary heart disease and dilatedcardiomyopathy (58 ± 3 to 55 ± 3 and 27 ±4 to 24 ± 4, both NS). No further significant changeoccurred after 2.5 minutes stimulation (53 ± 1, 58 ±3 and 23 ± 3, respectively). There was no differencein the pattern of left ventricular ejection fraction responsebetween the groups. Six controls, 4 patients with coronary heartdisease and 4 patients with dilated cardiomyopathy had a significantfall in left ventricular ejection fraction and 4, 5 and 6, respectively,developed a new or further deterioration in regional wall motion.Thus neither changes in regional wall motion nor left ventricularejection fraction response distinguished either patient groupfrom the normal controls. We do not recommend cold pressor stimulationas a diagnostic test for coronary heart disease.     

Reduced cold pressor pain tolerance in non-recovered whiplash patients: a 1-year prospective study.

Whiplash injury and chronic whiplash syndrome represent major health problems in certain western communities, pain being the main symptom. Sensitization of the nociceptive system may play a role for non-recovery after whiplash injury. AIMS: This study examined if tolerance to endure pain stimuli may predict outcome in whiplash injury. In a prospective fashion, 141 acute whiplash patients exposed to rear-end car collision (WAD grade 1-3) and 40 ankle-injured controls were followed and exposed to a cold pressor test, respectively, 1 week, 1, 3, 6 and 12 months after the injury. VAS score of pain and discomfort was obtained before, during and after immersion of the dominant hand into cold water for 2 min. The McGill Pain Questionnaire showed that ankle-injured controls had higher initial pain scores than the corresponding whiplash group, while whiplash-injured subjects had higher scores at 6 months; pain scores being similar at other time points. No difference was found in cold pressor pain between recovered whiplash patients and ankle-injured subjects. Non-recovery was only encountered in whiplash injury. Eleven non-recovered whiplash patients (defined as: handicap after 1 year) showed reduced time to peak pain from 1 week to 3 months (P<0.001), 6 months (P<0.01), but not 12 months after the injury. A larger pain area was seen in non-recovered vs. recovered whiplash-injured subjects during the entire observation period (P<0.001). Non-recovery after whiplash was associated with initially reduced cold pressor pain endurance and increased peak pain, suggesting that dysfunction of central pain modulating control systems plays a role in chronic pain after acute whiplash injury.     

Temporo-spatial analysis of cortical activation by phasic innocuous and noxious cold stimuli--a magnetoencephalographic study

Clinical findings and recent non-invasive functional imaging studies pinpoint the insular cortex as the crucial brain area involved in cold sensation. By contrast, the role of primary (SI) and secondary (SII) somatosensory cortices in central processing of cold is controversial. So far, temporal activation patterns of cortical areas involved in cold processing have not been examined. Using magnetoencephalography, we studied, in seven healthy subjects, the temporo-spatial dynamics of brain processes evoked by innocuous and noxious cold stimulation as compared to tactile stimuli. For this purpose, a newly designed and magnetically silent cold-stimulator was employed. In separate runs, cold and painful cold stimuli were delivered to the dorsum of the right hand. Tactile afferents were stimulated by pneumatic tactile stimulation.

Following innocuous cold stimulation (ΔT=5±0.3°C in 50±2 ms), magnetic source imaging revealed an exclusive activation of the contra- and ipsilateral posterior insular cortex. The mean peak latencies were 194.3±38.1 and 241.0±31.7 ms for the response in the ipsi- and contralateral insular cortex, respectively. Based on the measurement of onset latencies, the estimated conduction velocity of peripheral nerve fibres mediating cold fell in the range of Aδ-fibres (7.4±0.8 m/s).

Noxious cold stimulation (ΔT=35±5°C in 70±12 ms) initially activated the contra- and ipsilateral insular cortices in the same latency ranges as innocuous cold stimuli. Additionally, we found an activation of the contra- and ipsilateral SII areas (peak latencies 304±22.7 and 310.1±19.4 ms, respectively) and a variable activation of the cingulate cortex. Notably, neither cold- nor painful cold stimulation produced an activation of SI. By contrast, the evoked cortical responses following tactile stimulation could be located to the contralateral SI cortex and bilateral SII.

In conclusion, this study strongly corroborates the posterior insular cortex as the primary somatosensory area for cortical processing of cold sensation. Furthermore, it supports the role of SII and the cingulate cortex in mediating freeze-pain. Therefore, these results suggest different processing of cold, freeze-pain and touch in the human brain.     

Microvascular ultrastructure in non-freezing cold injuries

The effects of repeated local exposure to cold on the integrity of the subcutaneous microcirculation were studied in a model using a transparent tissue chamber implanted into a dorsal skin fold of Syrian hamsters. A detailed study of the vascular ultrastructure within the chamber revealed the following features: Endothelial damage was prominent in true capillaries and venous vessels, while arterioles remained unaffected. The endothelial lining appeared extremely attenuated around the entire vascular perimeter causing the development of “gaps”, some of which contained leukocytes or platelets. Smaller vessels were often completely filled with blood cells with leukocytes integrated into the endothelial wall. Fibrin was never observed within these occluded vessels. Finally, only veil-like remnants of the endothelium persisted, and compressed erythrocytes were still mimicking the original vascular outline. It is concluded that the ultrastructural changes observed after a repeated non-freezing cold injury closely resemble those observed during ischemia/reperfusion injury.     

自拟肩痹汤联合局部封闭治疗肩袖损伤寒湿凝滞证

目的:对自拟肩痹汤联合局部封闭治疗肩袖损伤(Rotator Cuff-Injury)的临床疗效评估。方法:选取门诊诊断为肩袖损伤的76例患者,按照基本资料随机分为两组,每组38例。对照组只按疗程给予常规用量的局部封闭药物治疗;实验组按疗程给予中药肩痹汤加减联合局部封闭药物治疗。治疗3个疗程后通过门诊随访调查患者治疗后肩袖损伤改善情况及Neer肩关节功能评分(疼痛、功能、运动范围、解剖)。结果数据分析处理采用SPSS21.0软件包,计量数据采用均数+标准差(x±s)结果检验,以P<0.05表示差异具有统计学意义。结果:治疗3个疗程后,2组患者均有较大改善,2组临床治疗总体有效率分析比较,实验组总体有效率(89.47%),对照组总体有效率(73.68%),两组间比较差异无统计学意义(P>0.05)。观察组治疗后的Neer肩关节功能评分的改善情况优于对照组,且差异有统计学意义。结论:自拟肩痹汤联合局部封闭治疗肩袖损伤(寒湿凝滞证)的临床疗效较单纯封闭治疗显著。     

高强度超声聚焦刀治疗晚期肿瘤的观察和护理

目的观察高强度超声聚焦刀(HIFU)治疗晚期肿瘤的并发症及护理。方法治疗前、治疗中、治疗后采取一整套护理方法,强调病人治疗前的心理护理;皮肤的间断冰敷;皮肤脱脂脱气的处理方法;治疗中生命体征的监测;治疗时合理体位的固定及治疗区皮肤的监测。结果通过超声聚焦刀治疗晚期肿瘤,本组31例患者均完成治疗,11例肿块明显缩小,肿瘤内血供消失或明显减少,回声明显增高,4例AFP降低,6例癌性癌痛缓解,10例大小无变化。结论高强度超声聚焦刀治疗晚期肿瘤,是一种新的治疗方法,只要护理得当,具有较好疗效。     

氩氦刀联合化疗治疗非小细胞肺癌12例护理体会

目的:探讨氩氦刀联合化疗治疗非小细胞肺癌患者的护理方法。方法:选择直低温介入冷热消融治疗设备(氩氦刀)联合含铂类二药联合化疗方案进行化疗。结果:术后病灶CT值的总体变化趋势降低,所有患者肿瘤标志物检测水平术后均未升高。结论:氩氦刀靶向治疗联合化疗治疗晚期肺癌,具有操作简单,安全性高,患者创伤少,副作用少的优点,尤其适合高龄、晚期非小细胞肺癌患者。     

高效价冷凝集素患者血型鉴定与输血治疗的研究

目的：探讨高效价冷凝集素患者血型鉴定新方法。方法：对高效价冷凝集素引起正、反定型不合者，采用加热洗涤和冷吸收法，以清除患者红细胞膜上和血清中存在的冷凝集素后，用盐水法作血型鉴定，Polybrine和微柱凝集交叉配血，及时准确地为患者配型输血。结果：2例恶性淋瘤和1例系统性红斑狼疮（SLE）患者血型正、反定型不合，主、次2侧均发生强凝集，不规则抗体呈强阳性；患者红细胞经37℃加热洗涤，于4℃条件下吸收冷凝集素后，血型分别定为Rh阳性AB型2例，0型1例，不规则抗体呈阴性，用Polybrene和微柱凝集配血相合。结论：用加热洗涤和冷吸收可排除高效价冷凝集素的干扰，便于血型鉴定和交叉配血。