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.     

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.     

Retrograde endoscopic laser therapy for transitional cell carcinoma of the upper urinary tract

AIM: The aim of the present study was to investigate the safety and efficacy of endoscopic laser therapy for transitional cell carcinoma (TCC) of the upper urinary tract. METHODS: Tumors of the renal pelvis and ureteropelvic junction were detected by ureteroscopy. The tumors were subjected to biopsy, and after TCC was diagnosed, endoscopic laser therapy (Neodymium-YAG and Holmium-YAG) was conducted using a 6.9 Fr. flexible ureterorenoscope. RESULTS: From January 1997 to April 2002, six patients underwent ureteroscopic treatment. Tumor grade was 1 in four patients and 2 in two patients. Average tumor size was 1.45 cm. Endoscopic treatment was chosen for two patients because of the high medical risk associated with open surgery. Another patient underwent diagnostic ureteroscopy, followed immediately by endoscopic treatment. A further three patients elected to undergo ureteroscopic treatment. One patient with large (3 cm), multifocal and incompletely treated tumors died of metastatic disease 22 months after the initial operation. One patient requested nephroureterectomy one month after endoscopic treatment, and pathological examination of the resected specimen revealed no tumor. The other four patients have been followed up for a mean period of 14 months after initial treatment. Recurrence occurred in one patient, and was successfully treated by repeat endoscopic resection. None of the patients required blood transfusion or emergency open surgery. CONCLUSION: Ureteroscopic treatment of small, localized, low-grade TCC of the upper urinary tract is now a safe and feasible alternative to nephroureterectomy in selected patients.     

Initial experience with carbon dioxide laser laparoscopy

Adhesions and endometriosis are commonly encountered among patients presenting with pelvic or lower abdominal pain and also in a significant proportion of infertile patients. Laparoscopic investigation is usual in patients with these problems, and it has been possible to perform endoscopic surgery with special scissors and electrodiathermy. These methods can cause troublesome bleeding, and the diathermy produces high temperatures which can be hazardous if used in the vicinity of the bowel. The carbon dioxide laser can be used endoscopically to vaporize deposits of endometriosis and adhesions with great precision and virtually no bleeding. One hundred consecutive patients with endometriosis or adhesions were treated with the CO₂ laser laparoscope and followed up for at least a year. Seventy-five per cent of patients with pain due to endometriosis were cured, and 68% of patients were better after laser laparoscopic adhesiolysis. Pregnancy rate in the previously infertile group with endometriosis was 64%. There were no complications due to the intra-abdominal use of CO₂ laser energy under endoscopic control, although there is a need for a controlled trial. It appears that in the hands of an experienced laparoscopist this technique is safe and effective.     

The modification of the new type of end-to-side anastomosis between carotid arteries in rats: A technical and Scanning Electron Microscopic study

Summary Modification of a type of end-to-side anastomosis that has been described before is studied. The recipient artery is occluded for only 3–4 minutes to complete the anastomosis by using only the running suture. The anastomotic site was studied by inspection and Scanning Electron Microscope (SEM) at different times after the operation on 30 rats.     

Radionuclide ventriculography (equilibrium gated blood pool scanning) —its present clinical position and recent development

Myocardial scanning (MS) and radionuclide ventriculography (RNV) are the foundation of nuclear cardiology. These procedures aim in two completely different directions: RNV tries to image heart motion, that is, mechanical (pump) function, and therefore belongs to the group of first-order functional imaging (FI, imaging mechanical function), whereas MS is based on myocardial metabolism, and therefore can be attributed to third-order functional imaging (metabolism). This statement is relevant for the assessment of the clinical position of RNV: Third-order (metabolism) functional imaging is the domain of nuclear medicine (NM), whereas first-order FI has to face the competition of alternative noninvasive procedures such as ultrasound (US), digital subtraction angiography (DSA), computer tomography (CT), and nuclear magnetic resonance (NMR). The domain of RNV includes stages two (acute infarction) and three (postinfarction period) of coronary arterial disease (CAD). The advantageous combination of quantitative data on global, left ventricular (LV) function and imaging of regional motion ensures the superiority of RNV over US. However, RNV is inferior to MS in physical examinations in the preinfarction stage of CAD, whereas US is clearly inferior to both NM procedures. Recent progress could be attained by gated SPECT (GASPECT). A proposal is presented for simplification of this time-consuming procedure. Technetium-labeled isonitriles offer the chance for the combination of perfusion-motion imaging of the myocardium. However, even standard RNV offers new possibilities. The multitude of parameters produced by quantitation has not yet been exploited completely. This can be done by discriminant analysis. The computer finds out an optimal subset from the whole set of parameters for the solution of a significant clinical problem. The software learns to find the label of a special pathognomonic entity. This computer work is supported by a relational data bank (Oracle) and an optical disk. Two examples for the effectiveness of the computer in problem solving are presented. It is concluded that RNV, even in the very competitive class of first-order functional imaging, enjoys a preferred position. The future indeed seems brighter because labeled isonitriles offer the chance for the combination of perfusion-motion imaging of the myocardium.Dedicated to Prof. Heinz Hundeshagen on the occasion of his 60th birthday     

Reversible changes of visual acuity and pattern-electroretinograms after blue-green argon laser photocoagulation of diabetic patients

Visual acuity, color vision, pattern-visual-evoked-potentials (P-VEPs) and pattern-electroretinograms (P-ERGs) were measured in 13 diabetic subjects before, and 24 hours and 5 weeks after blue-green argon laser treatment. As control, the same examinations were performed in 7 normal subjects and 7 diabetic patients before and after slit lamp examination with the Goldman three mirror contact lens.Visual acuity and P-ERG amplitudes were significantly reduced one day after the laser treatment, while 5 weeks after the laser coagulation, visual acuity and P-ERG amplitudes recovered to pretreatment values. The control group showed no significant changes after slit lamp examination. Since fluorescein angiography revealed no macular changes after laser treatment, the possibility of a reversible functional light damage after blue-green argon laser coagulation (ALC) is discussed.This study was supported by the Medizinisch - Wissenschaftlicher Fonds des Bürgermeisters der Bundeshauptstadt Wien.     

Linear Unsaturated Polyamides: Nylons 6 u18 and 18 u18

Summary: Linear unsaturated nylons 6 u18 and 18 u18 have been made containing a double bond in the center of the diacid segment with potential for additional functionalization. Solution state NMR showed the presence of a small portion of cis amide units. Solid state NMR verified the presence of the double bond in the bulk, and that the polyamides were present in the α‐crystalline form. Thermal stability was comparable to linear saturated nylons, and the melting and crystallization temperatures of the unsaturated nylons were lower compared to the saturated analogs.

DSC heating and cooling thermograms for nylons 6 u18 and 18 u18.     

Structure, Metabolism, and Functions of Peripheral Blood Lymphocytes during Long-Term Persistence of Epstein-Barr Virus

Study of surface architectonics, blast transformation potential, and cytochemical activity of peripheral blood lymphocytes from children infected with Epstein-Barr virus revealed imbalance between structural, metabolic, and functional state of lymphocytes. This imbalance persists in delayed period after infection and determines long-term viral persistence in the macroorganism.     

Separate and variably shaped chromosome arm domains are disclosed by chromosome arm painting in human cell nuclei

Fluorescence in situ hybridization (FISH) with microdissection probes from human chromosomes 3 and 6 was applied to visualize arm and subregional band domains in human amniotic fluid cell nuclei. Confocal laser scanning microscopy and quantitative three-dimensional image analysis showed a pronounced variability of p- and q-arm domain arrangements and shapes. Apparent intermingling of neighbouring arm domains was limited to the domain surface. Three-dimensional distance measurements with pter and qter probes supported a high variability of chromosome territory folding.