Influence of volume replacement with different HES–solutions on microcirculatory blood flow in cardiac surgery

A variety of hydroxyethyl starch (HES) preparations with different molecular weight average (Mw) and molar substitution (MS) is available for volume replacement during acute normovolemic haemodilution (ANH). Particularly with regard to microcirculation, the ideal solution for volume therapy has not been found. A 5th group without ANH served as a control (10 patients in each group). In addition to systemic haemodynamics and various laboratory parameters, skin capillary blood flow was measured by laser Doppler flowmetry. Laser Doppler flow (LDF) was monitored simultaneously at the patient's forehead and forearm. Changes in systemic haemodynamics were similar in all ANH–patients. Systemic vascular resistance (SVR) was lowest after infusion of HES 200/0.5. The most pronounced increase in plasma viscosity was in patients of group 1 (450/0.7) (P<0.05) and plasma viscosity remained highest during the entire investigation period in these patients. After ANH, skin capillary blood flow measured at the forehead decreased in all patients except in patients of group 2 (200/0.5: max. + 18%). Group 3 (200/0.62) showed the highest decrease in forehead–LDF. During CPB, forehead–LDF decreased significantly in groups 3 (200/0.62) and 4 (40/0.5). At the end of the operation, LDF was most reduced in groups 1 (– 32%) and 3 (– 33%). Forearm–LDF increased in all ANH–patients. Immediately after ANH this increase was lowest in group 3 (200/0.62). In the further course of the investigation, no more differences were seen in any HES patients. The different HES preparations showed a different microcirculatory response. 6% HES 200/0.5 seems to be overall most suitable for volume replacement in cardiac surgery patients undergoing acute normovolemic haemodilution (ANH) due to the best effects on microcirculatory skin perfusion assessed by laser Doppler flow. HES 6% 200/0.62 showed the overall least positive effects with regard to skin capillary blood flow in this situation.     

Experimental study of spinal cord compression by epidural tumors using electron probe X-ray microanalysis and confocal laser scanning microscopy

Changes in the nerve fibers of the spinal cord were studied in rat experimental epidural tumor models. Light microscopy showed demyelinization in all with rats paraparesis and paraplegia. Cross-sectional views of nerve fibers stained with 3,3dipentyloxacarbo-cyanine iodide, obtained by confocal laser scanning microscopy, showed distorted, shrunken fibers with a low fluorescence intensity. Changes in the electrolyte contents of nerve fibers were studied by electron probe X-ray microanalysis. The K concentration in axons and the myelin sheath was increased in the paraparesis group, but was decreased in the paraplegia group. These findings suggest that, in the paraparesis group, compression of the spinal cord damaged cell membrane channels, which subsequently caused an increase in intracellular K, a decline in the action potential, and low-intensity fluorescence of nerve fibers. On the other hand, in the paraplegia group, destruction of cell membranes caused a decrease in intracellular K until it approached the extracellular level. This reduced both the action potential and the fluorescence intensity. As Ca and Mg concentrations in both axons and the myelin sheath increased in relation to the severity of neurologic damage, it appears that these electrolytes may also play an important role in damage to nerve fibers.     

Three-dimensional recording of the human face with a 3D laser scanner.

Three-dimensional recording of the surface of the human body or of certain anatomical areas has gained an ever increasing importance in recent years. When recording living surfaces, such as the human face, not only has a varying degree of surface complexity to be accounted for, but also a variety of other factors, such as motion artefacts. It is of importance to establish standards for the recording procedure, which will optimise results and allow for better comparison and validation. In the study presented here, the faces of five male test persons were scanned in different experimental settings using non-contact 3D digitisers, type Minolta Vivid 910). Among others, the influence of the number of scanners used, the angle of recording, the head position of the test person, the impact of the examiner and of examination time on accuracy and precision of the virtual face models generated from the scanner data with specialised software were investigated. Computed data derived from the virtual models were compared to corresponding reference measurements carried out manually between defined landmarks on the test persons' faces. We describe experimental conditions that were of benefit in optimising the quality of scanner recording and the reliability of three-dimensional surface imaging. However, almost 50% of distances between landmarks derived from the virtual models deviated more than 2mm from the reference of manual measurements on the volunteers' faces.     

Helium-neon laser: A contraindication for infected wounds? In vitro study on pseudomonas aeruginosa

The purpose of this investigation was to examine the susceptibility ofPseudomonas aeruginosa to helium-neon (He-Ne) laser in order to gain an insight into the clinical implications for this type of low-level laser therapy (LLLT) in the treatment of infected wounds. Suspensions, in the presence and the absence of methylene blue (MB, 0.001% w/v), were exposed to the light from a 9 mW He-Ne laser for 5 and 50 min. Exposure of samples without MB did not affect the viability of this organism based on the lack of significant differences in the number of colony forming units (CFU) between irradiated and control samples. In the presence of MB, statistically significant mean reductions in CFU of 39.5% (22.6 J cm^-2) and 58.2% (226 J cm^-2) were found, and growth-free zones in irradiated confluent platings could be observed. Since no logarithmic reductions were achieved, the clinical implementation of He-Ne laser as a bactericidal agent seems to be of no relevance yet. Otherwise, no stimulation of bacterial growth was observed. Therefore, infection as a contraindication for LLLT should be excluded.     

激光雾化治疗机的研制

介绍一种新型激光治疗装置.它利用超声波产生的雾化气体通道作为光学传导媒介,将激光束汇同雾化药雾通过患者的深呼吸一起传导至患者的呼吸道及肺部,进行治疗.     

Stereotaxic Interstitial Laser Therapy of Early-Stage Breast Cancer

Abstract: Coagulation leading to fibrosis of mammo-graphically detected breast cancers by interstitial laser therapy was tested as an alternative to surgical removal. Availability of computerized stereotaxic digital imaging allows the precise placement of laser and thermal needles into the target tumor and its controlled ablation by heat. The methodology of interstitial laser therapy (ILT), evolution of the subsequently removed tumors, and their histologic appearance are outlined.
Eight patients with mammographically well-defined tumors were selected. Definitive diagnosis and receptor evaluation were made on core biopsies. Under local anesthesia, stereotaxically guided diode laser energy at 5–10 w was delivered via a 400 xm fiber in a 19-gauge needle placed into the center of the tumor until the peripheral temperature exceeded 60°C. Patients experienced transient pain and pyrexia. Subsequent to ILT, seven invasive carcinomas were excised while one case of multiple papillomas was kept under surveillance. Histologic study revealed central necrosis but some peripheral residual tumor in the first five cases. In the last two, central necrosis surrounded by concentrically arranged, recognizable but severely injured, focally "windswept" and "ghostlike" tumor and granulation tissue were noted. The multiple papillomas showed radiologic shrinkage at 5 months and extensive fibrosis on needle biopsy.
ILT is an attractive new method of treating small, well-defined breast tumors and offers a potentially significant alternative to surgical removal; further exploration is warranted.     

In vitro evaluation of ablation parameters of normal and fibrous aorta using smooth excimer laser coronary angioplasty

A modified exeimer laser energy delivery system was used to irradiate 100 segments of normal and fibrous aorta in vitro. The laser beam was scanned into 8 fiber bundles consisting of 50 fibers each resulting in a reduction of the applied pulse energy. The total repetition rate was increased to 150 Hz in order to keep the repetition rate per fiber bundle close to 20 Hz and to minimize thermal injury. The results demonstrate that effective ablation (etch rate per 8 pulses > 2.0 μm) occurred at an energy fluency of 50 mJ/mm² in both normal and fibrous aorta. Tissue damage (carbonization, tissue separation, fissures, cracks, and vacuolization) was in a range of 100 ± 28 to 152 ± 30 μm for normal aorta and in a range of 57 ± 35 to 110 ± 39 μm for fibrous aorta. We conclude that effective ablation of normal and fibrous human aorta can be achieved by the application of smooth excimer laser coronary angioplasty. This improvement of excimer laser technology may result in a reduction of shock wave- and cavitation-induced damage leading to a reduction of tissue injury. However, this awaits further in vitro and in vivo confirmation. © 1993 Wiley-Liss, Inc.     

准分子激光冠状动脉成形术的初步临床应用经验

目的：介绍准分子激光冠状动脉成形术（ＥＬＣＡ）治疗冠状动脉狭窄的临床应用经验。材料和方法：１０例冠心病患者作冠状动脉造影确认有１４支冠状动脉狭窄（狭窄率７０％～７５％者５支，９０％～１００％者９支）。全部病例均作ＥＬＣＡ手术。ＥＬＣＡ采用脉冲间期为１８０－２２０ｍｓｅｃ，光导纤维直径为１．３～１．６ｍｍ，能量密度１４．５～２１．０ｍＪ，激光频率为２０Ｈｚ。ＥＬＣＡ术后辅以球囊扩张血管成形术（ＰＴＣＡ）。结果：９例１３支狭窄动脉中，９支狭窄率＞９０％者，作ＥＬＣＡ＋ＰＴＣＡ成功，其中７支动脉狭窄率减至１５％以下，２支减至４０％～４５％，１例因术中导丝头断裂，失败。成功的９支动脉术后冠状动脉造影示：内膜光滑４支，毛糙３支，夹层动脉瘤１支（２月后随访消失），术中出现血栓１支。术后６个月内造影随访，３例动脉再度狭窄。结论：准分子激光冠状动脉成形术可用于ＰＴＣＡ难以成功的有钙化硬斑、挟窄段较长（＞２．０ｃｍ）和闭塞的冠状动脉，安全有效。但它并不能避免术后再狭窄的发生。     

透明晶体超声乳化摘除和低或负度数折叠人工晶体植入治疗高度近视

目的:探讨透明晶体超声乳化吸出并植入后房型折叠人工晶体矫正高度近视的安全性和有效性.方法:对32例(50眼)均采用表麻下经透明角膜切口行透明晶体超声乳化吸出并植入后房型折叠人工晶体.眼轴长平均29.64mm.比较手术前后最佳矫正视力(BCVA),散光度及角膜内皮计数,随访观察手术并发症情况.并对术前BCVA低于0.3的37只患眼应用扫描激光检眼镜(SLO)的微视力软件,检查微视力,评估术后潜在视力.周边视网膜格子样变性7只眼,均行氩激光周边变性区光凝.结果:术后随访平均24月.BCVA由术前0.20±0.19,术后提高到0.61±0.24,其中≥0.5的由术前4只眼(8％)增加到34只眼(68％)。手术前后平均散光度比较,经t检验无显著性差异(P>0.1).手术后无1例发生视网膜脱离,有5只眼发生后发障,均行YAG激光治疗.角膜内皮计数术后平均损失207个/mm2±96个/mm2.且SLO作为术后潜在视力预测手段拥有很高的准确度(94.6％).结论:透明晶体超声乳化摘除加后房型折叠人工晶体植入矫正高度近视是少数屈光矫正有效方法之一,可获得较好的术后BCVA.但是熟练掌握超声乳化手术操作及采取术前积极的预防性治疗是开展此项技术的根本和关键,且需进行长期的临床随访.     

内镜激光治疗食管和贲门早期表浅癌疗效及DNA和p53表达与预后关系的研究

目的：研究内镜Ｎｄ：ＹＡＧ激光治疗食管和贲门早期表浅癌的远期疗效和ＤＮＡ及ｐ５３表达与预后的关系。方法：对内镜激光治疗癌细胞消失的３２例食管和贲门早期表浅癌病人进行３３～７８个月（平均５５．３个月）的随访。并与１１７例早期食管癌和贲门癌的自然病程对比分析。应用ＰｒｏｄｕｃｔＬｉｍｉｔＥｓｔｉｍａｔｅ方法计算其存活率。应用免疫组化染色法检测ｐ５３表达。应用分光光度计测定癌细胞ＤＮＡ含量。结果：内镜激光治疗５年存活率为９７％，自然病程５年存活率为６７％（Ｐ＜０．０１）。ｐ５３阳性表达和ＤＮＡ非整倍体型病人的复发率分别为７６．９％和６４．３％。结论：内镜Ｎｄ：ＹＡＧ激光是治疗食管和贲门早期表浅癌的有效方法。抗癌基因ｐ５３和ＤＮＡ倍体数与病人的预后有关。