A new model for studying microcirculatory changes during dermal wound healing

Intact blood supply by microcirculation to a wounded site is an indispensable prerequisite for normal tissue regeneration. However, microvascular changes taking place in the healing process of skin wounds are not understood due to the fact that only few models allow chronic in vivo studies on skin micro-circulation. Therefore, we have modified the hairless mouse ear model with the purpose of a quantitative in vivo study of microhemodynamic changes throughout the healing process. Following the creation of a standardized skin wound on the ear of the homozygous hairless mouse (hr/hr), microvessel diameters, red blood cell velocities, wet weight, and leucocyte content of the ear tissue were determined. Surface area of the wound was assessed until complete closure was achieved. By repeated measurements at identical sites over the entire healing period, a distinct pattern of microvascular changes could be observed: microvessel diameters increased to a maximum a few days after wound creation, whereas red blood cell velocities reached their highest values at a later point in time and were still elevated after complete reepithelization of the wounds. Edema and leucocyte content of the ear tissue was most prominent in the early healing phase and gradually decreased to normal values thereafter. These results demonstrate changes of the microvasculature of the hairless mouse ear to injury, which are in accordance to other more indirect studies on this topic. Therefore, we conclude that the model presented is suitable for prolonged quantitative analysis of microcirculation during normal wound healing and may be used to assess microvascular changes taking place during wound healing in pathologically altered tissue.     

提高休克患者静脉穿刺成功率的探讨

目的:探讨提高休克病人静脉穿刺成功率的方法,为抢救休克病人赢得时间.方法:对120例休克病人随机分成两组,实验组60例,对照组60例.实验组按新方法进行静脉穿刺,而对照组仅给予一般常规穿刺方法进行穿刺.结果:采用新方法穿刺成功率为95%(57例),采用常规穿刺法的成功率为85%(51例).经过统计学分析有统计意义(P<...     

Comparison of (immuno-)fluorescence data with serial [F]Fmiso PET/CT imaging for assessment of chronic and acute hypoxia in head and neck cancers

Purpose

Both, acute and chronic hypoxia can have unfavorable impacts on tumor progression and therapy response. The aim of this study was to optimize a macroscopic technique for the quantification of acute and chronic hypoxia (Wang model assessment of serial [¹⁸F]Fmiso PET/CT imaging) by comparing with a microscopic technique [(immuno-)fluorescence staining in tumor cryosections].

Materials and methods

Tumor pieces from the human squamous cell carcinoma lines from the head and neck FaDu and CAL33 were xenografted into the hind leg of NMRI nu/nu mice. Tumor-bearing mice were placed on an in-house developed multi-point fixation system and subjected to two consecutive dynamic [¹⁸F]Fmiso PET/CTs within a 24 h interval. The Wang model was applied to SUV (standard uptake values) to quantify the fractions of acute and chronic hypoxia. Hypoxia subtypes were also assessed in vital tumor tissue of cryosections from the same tumors for (immuno-)fluorescence distributions of Hoechst 33342 (perfusion), pimonidazole (hypoxia), and CD31 (endothelium) using pattern recognition in microcirculatory supply units (defined as vital tumor tissue area supplied by a single microvessel).

Results

Using our multi-point fixation system, acceptable co-registration (registration errors ε ranged from 0.34 to 1.37) between serial PET/CT images within individual voxels was achieved. The Wang model consistently yielded higher fractions of acute hypoxia than the MCSU method. Through specific modification of the Wang model (Wang_mod), it was possible to reduce the fraction of acute hypoxia. However, there was no significant correlation between the fractions of acute hypoxia in individual tumors assessed by the Wang_mod model and the MCSU method for either tumor line (FaDu: r = 0.68, p = 0.21 and CAL33: r = 0.71, p = 0.18). This lack of correlation is most-likely due to the difference between the non-linear uptake of [¹⁸F]Fmiso and the spatial assessment of MCSUs.

Conclusions

Whether the Wang model can be used to predict radiation response after serial [¹⁸F]Fmiso PET imaging, needs to be confirmed in experimental and clinical studies.     

重症急性胰腺炎与微循环障碍

在广泛查阅文献的基础上,作者对重症急性胰腺炎时微循环的改变进行综述。重症急性胰腺炎时,胰腺的微循环发生一系列改变,包括微血管收缩、血管通透性增加、血液灌注量减少、局部缺血等。胰腺微循环障碍在重症急性胰腺炎的发生发展过程中起着重要的作用。     

血栓素前列环素在大鼠轻症急性胰腺炎向重症急性胰腺炎转变中的变化和意义

目的 本实验旨在探讨血栓素、前列环素在轻症急性胰腺炎(MAP)向重症急性胰腺炎(SAP)转变中的变化和意义.方法 将SD大鼠40只按编号法随机分为假手术组(n=8)、MAP组(n=8)、SAP组(n=24).经胆胰管逆行加压注入2.5%牛磺胆酸钠建立大鼠MAP模型,在此基础上通过暂时阻断脾下动脉引发缺血再灌注损伤微循环障碍以产生SAP模型.术后6h剖杀各组大鼠,检测各组大鼠血液中血栓素(TXA2)、前列环素(PGI2)的含量,并观察其病理改变.结果 MAP组大鼠较假手术组胰腺病理组织学评分显著增高(P＜0.05),血栓素与前列腺环素的比值(T/P)值则无明显差异;而SAP组(钳夹脾下动脉15、30、60 min)较MAP组T/P值、胰腺病理组织学评分均有显著增高(P＜0.05).结论 胰腺微循环障碍作为持续和加剧损害因素贯穿于SAP发展的全过程,是MAP向SAP转化的重要因素.     

动态监测氧利用率判定烧伤病人微循环障碍的程度

动态监测氧利用率判定烧伤病人微循环障碍的程度李志伟＊邢继平＊佟新＊姜波＊隋健＊谢秋幼＊于淑琴＊杨晓波＊休克是烧伤早期的严重并发症，与ＭＯＦ、感染的关系极为密切，其实质是毛细血管灌流量骤减所造成的组织和器官中的微循环障碍。因而判定烧伤后微循环的程度对指...     

Improvement of Microcirculatory Blood Flow under Epidural Spinal Cord Stimulation in Patients with Nonreconstructible Peripheral Arterial Occlusive Disease

Abstract: Epidural spinal cord stimulation (ESCS) has been suggested as a method to improve microcirculatory blood flow and to reduce the amputation rate in vascular patients. We studied the effects of ESCS on microcirculatory blood flow in 237 patients with nonreconstructible peripheral arterial occlusive disease. Clinical status was classified as Fontaine Stage 3 (ischemic rest pain) in 169 patients and as Fontaine Stage 4 (ulcers/gangrene) in 68 patients. After a mean follow-up period of 31.2 months, major pain relief (<75%) was noticed in patients who retained their limbs. Sixty-four patients underwent major amputation despite ESCS. Clinical improvement was confirmed by the increase in transcutaneous oxygen (TcPo₂).     

Organic grape juice intake improves functional capillary density and postocclusive reactive hyperemia in triathletes

OBJECTIVE:

The aim of this study was to evaluate the effect of organic grape juice intake on biochemical variables and microcirculatory parameters in triathlon athletes.

INTRODUCTION:

The physiological stress that is imposed by a strenuous sport, such as a triathlon, together with an insufficient amount of antioxidants in the diet may cause oxidative imbalance and endothelial dysfunction.

METHODS:

Ten adult male triathletes participated in this study. A venous blood sample was drawn before (baseline) and after 20 days of organic grape juice intake (300 ml/day). Serum insulin, plasma glucose and uric acid levels, the total content of polyphenols, and the erythrocyte superoxide dismutase activity were determined. The functional microcirculatory parameters (the functional capillary density, red blood cell velocity at baseline and peak levels, and time required to reach the peak red blood cell velocity during postocclusive reactive hyperemia after a one-min arterial occlusion) were evaluated using nailfold videocapillaroscopy.

RESULTS:

Compared with baseline levels, the peak levels of serum insulin (p = 0.02), plasma uric acid (p = 0.04), the functional capillary density (p = 0.003), and the red blood cell velocity (p<0.001) increased, whereas the plasma glucose level (p<0.001), erythrocyte superoxide dismutase activity (p = 0.04), and time required to reach red blood cell velocity during postocclusive reactive hyperemia (p = 0.04) decreased after organic grape juice intake.

CONCLUSION:

Our data showed that organic grape juice intake improved glucose homeostasis, antioxidant capacity, and microvascular function, which may be due to its high concentration of polyphenols. These results indicate that organic grape juice has a positive effect in endurance athletes.     

Cutaneous responses to topical methyl nicotinate in black,oriental, and caucasian subjects

Summary The response of human skin to topical methyl nicotinate (MN) has been monitored in black, oriental, and caucasian subjects. The study aimed to address the question: Do racial differences in percutaneous absorption and microcirculatory sensitivity exist? MN-induced vasodilation was assessed visually and by laser Doppler velocimetry (LDV). At three dose levels, in the three subject populations, four parameters were compared: (a) the diameter of the maximum visually perceptible erythematous area (E_mx); (b) the area under the erythematous diameter versus time curve (AUE); (c) the maximum LDV response (L_mx); and (d) the area under the LDV response versus time curve (AUL). At p<0.05, AUL (black)>AUL (caucasian) for all MN concentrations; AUL (oriental)>AUL (caucasian) for the higher dose levels. E_mx, AUE and L_mx showed no significant differences between races within concentrations. For all subjects, E_mx AUE, and AUL were significantly dependent on MN dose whereas L_mx was not. The results suggest that some racial differences in response to topical MN exist and that perception of these distinctions may depend upon the method of measurement.