Morphology of corneal nerves in soft contact lens wear. A comparative study using confocal microscopy

The aim of this study was to evaluate corneal innervation in soft contact lens wearers using the Tomey Confoscan confocal microscope (40x/0.75 objective lens). Three distinct age- and sex-matched subject groups were involved, including extended soft (hydrogel and silicone-hydrogel) contact lens wearers, overnight soft (hydrogel) contact lens wearers, and non contact lens wearers. A number of variables were objectively measured, subjectively evaluated, or graded in order to investigate the distribution and morphology of corneal nerves. For most of the evaluated parameters, no statistically significant differences were found. However, qualitative observations showed noticeable differences in corneal nerve appearance among the different subject groups; the degree of corneal oedema was suggested as the main causative factor. In conclusion, neither the short-term (overnight wear) nor the long-term (12-month extended wear) soft contact lens wear appeared to affect the morphology and/or distribution of corneal nerves as viewed with confocal microscopy.     

STANDARD IMAGING TECHNIQUES OF ENDOSCOPIC ULTRASOUND‐GUIDED FINE‐NEEDLE ASPIRATION USING A CURVED LINEAR ARRAY ECHOENDOSCOPE

Standard imaging techniques using a curved linear array echoendocope are summarized to facilitate the attainment of expertise in endoscopic ultrasonography and endoscopic ultrasound‐guided fine needle aspiration, and to promote the widespread use of this diagnostic and therapeutic tool. Typical images of the mediastinal organs, the bilio‐pancreatic systems and neighboring organs by scanning from the esophagus, stomach, duodenal bulb, and descending portion of the duodenum, are shown in a sequential manner. The basic techniques of endoscopic ultrasound‐guided fine needle aspiration are also presented.     

Laser photobioactivation mechanisms: in vitro studies using ascorbic acid uptake and hydroxyproline formation as biochemical markers of irradiation response

Clinical investigations of laser photobioactivation, or biostimulation, might be differently designed and more fruitful if knowledge of basic biochemical mechanisms were better understood. In this investigation, biochemical events identified as responses to 904 nm irradiation included increased ascorbic acid uptake by fibroblasts. These cells also showed increased hydroxyproline formation, and this was increased several-fold by the addition of proline to the medium. Maximum biochemical responses were observed at a pulse frequency of 67 Hz and a pulse width of 150 nsec with an energy density of approximately 7 mJ/cm2 per exposure. Elements in the mitochondrial cytochrome system are proposed as the radiation absorbing chromophore(s). Hypothetically, the energy generated is linked to ascorbic acid uptake, which in turn stimulates collagen synthesis.     

Fluorescein angiographic findings and results of laser treatment in circumscribed choroidal hemangioma

We studied retrospectively 12 eyes with a solitary choroidal hemangioma in 12 patients over a period of 13 years. A peculiar, even hyperfluorescence of the tumor within the retinal venous phases occurred in all 12 cases. In all but four patients, laser therapy was performed to reduce subretinal fluid and partially destroy the tumor. Two of the three eyes without extensive retinal detachment or cystoid macular edema at the initial visit regained a final vision of 20/30 or better. The remaining 5 patients with the two major complications had a final vision of 20/80 or worse due to degenerative retinal changes. We believe that laser treatment is definitely advisable in the early stages of a circumscribed choroidal hemangioma.The study was performed at the Institute of Ophthalmology, University of Nijmegen.     

Pulsed CO2 laser tissue ablation: effect of tissue type and pulse duration on thermal damage

Tissue removal by infrared lasers is accompanied by thermal damage to nonablated tissue. The extent of thermal damage can be controlled by a choice of laser wavelength, irradiance, and exposure duration. The effect of exposure duration has been studied in vivo by using CO2 lasers with pulse widths that vary from 2 microseconds to 50 msec. Pulse widths of 50 msec, typical of a shuttered, continuous-wave CO2 laser, produce damage regions 750 micron wide in normal guinea pig skin; the use of a 2-microseconds-long pulse reduced this damage zone to as little as 50 micron. Using 2-microseconds-long pulses, in vitro studies showed that the minimum zone of thermal damage varied significantly with tissue type. The thermal denaturation of these tissues has been studied and correlated with damage. The effect of denaturation temperature and pulse duration on the width of the damage zone is explained by a simple model.     

Continuous laser radiation effect at 1.06 microns on gastrointestinal tract

The thermal effect of 1.06 microns YAG:Nd laser irradiation at temperature conditions up to 100 degrees C without crater formation on gastrointestinal (GI) tissue samples was investigated. The theoretical and experimental data show that at an intensity of 160-400 W/cm2 laser-induced heating of the tissue with an initial temperature of 20 degrees C leads to coagulation lesions at a temperature no less than 60 degrees C and at a depth of 1.7-2.1 mm.     

Laser interstitial thermotherapy in stereotactical neurosurgery

The authors present their first experience with laser interstitial thermotherapy, (ITT). Four patients with deep-seated non-infiltrative benign tumours (three astrocytomas, one oligodendrocytoma) underwent ITT. Previously, a stereotactic procedure had been performed to determine the exact location of the tumour, its spatial configuration and its histological diagnosis. The MRI controls confirmed the efficacy of hyperthermia on the tumour tissues. The authors discuss the possible ITT mechanisms. The indications of such laser ITT in neurosurgery should be enlarged to malignant tumours (gliomas, metastases) and to certain hypophyseal adenomas.     

大白鼠肾上腺的血管构筑

本实验采用血管铸型扫描电镜,注射明胶卡红组织切片显微镜下观察和注射铅丹乳胶追踪血管来源三种方法对14只健康大白鼠肾上腺血管构筑进行了研究。大白鼠肾上腺动脉发自腹主动脉和肾动脉。它们在行程中发出分支至腺体表面,再次分支穿入囊内,逐级分支至毛细血管。皮质动脉发自囊内血管,它们在皮质中分支分布。球状带的毛细血管与囊的毛细血管相连,毛细血管在球状带围绕细胞团形成网眼状;在束状带呈放射状排列;在网状带吻合增多形成网状。髓质动脉亦发自囊的血管,它们在皮质中不发分支直抵髓质,在髓质分成毛细血管。网状带的毛细血管越向髓质口径越粗,它们在皮髓交界处互相吻合形成更粗的静脉,这些静脉逐级吻合,最后形成一主干——中央静脉,它穿出皮质出现于肾上腺门处。左侧的中央静脉注入在肾静脉,右侧的注入下腔静脉。     

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.     

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.