Effects of contusion and cryotherapy on microvascular perfusion in rat dorsal skeletal muscle

Dorsal microcirculatory chambers (DMCs) were surgically implanted in the backs of rats to expose, beneath a transparent coverslip, the skeletal muscle microvasculature under the skin; two studies were completed using this model. In one study, microvascular perfusion was monitored for 96 h with laser Doppler fluxmetry and laser Doppler perfusion imaging to measure microvascular perfusion before and after contusion of the skeletal muscle within the DMC. There were statistically significant differences in microvascular perfusion observed with laser Doppler fluxmetry (baseline vs. postcontusion at 48 h) and with the scanning laser Doppler perfusion imager (baseline vs. postcontusion at 96 h). The second study monitored changes in microvascular perfusion following 20 min of local ice application to the back side (fur and skin side) of the DMC. Ice application resulted in a statistically significant reduction in microvascular perfusion as demonstrated by both laser Doppler instruments. The use of the two laser Doppler instruments with this model of skeletal muscle microcirculation provides direct measurements of microvascular perfusion that can be used to monitor the effect of contusion and cryotherapy on skeletal muscle microcirculation.     

激光血疗治疗脑外伤的临床研究

本文对l7例脑外伤病人应用激光量子辐照血液疗法(LQB)进行临床研究。该疗法采用低功率调制式脉冲氦氖激光作主要辐照光源,是紫外光自血回输疗法(UIB)的最新进展。由于激光及充氧的作用,能迅速改善血氧状况、活化血的细胞功能、血液流变等参数和微循环状况、促进新陈代谢,提高机体免疫功能及抗病能力。临床初步观察,发现它对颅脑损伤,包括脑震荡、脑挫裂伤、脑水肿及颅压增高、外伤性脑梗塞、术后恢复期等有显著疗效,总有效率达100％。     

小光斑飞点扫描式准分子激光原位角膜磨镶术治疗远视

目的 评价小光斑飞点扫描式准分子激光系统用于准分子激光原位角膜磨镶术治疗远视的有效性、预测性和安全性。方法 采用Keracor217z准分子激光机对27例48眼远视患者（＋1．50-＋6．00D），行准分子激光角膜原位磨镶术，术后随访6个月。结果 术后6个月时，最佳矫正视力与术前相比，未见视力下降超过1行以上者，91．6％的患者裸眼视力达到0．5以上，100％的患者裸眼近视力达到0．5以上，术中术后无严重并发症。结论 小光斑飞点扫描式准分子激光系统治疗远视的临床效果较好，大大减少了手术并发症的发生率。     

Short-term effects of 308-nm xenon-chloride excimer laser and narrow-band ultraviolet B in the treatment of vitiligo: a comparative study

We compared the clinical efficacy of a short-term intervention of 308-nm excimer laser with that of narrow-band UVB (NBUVB) phototherapy for vitiligo patients to see the early response. Twenty-three symmetrically patterned patches of vitiligo on 8 patients were selected. Vitiligo patches on one side of the body were treated 2 times per week for a maximum of 20 treatments with the excimer laser, and NBUVB phototherapy was used on patches on the other side. Improvement (repigmentation) was assessed on a visual scale via serial photographs taken every five treatments and scored as follows: 0,< or =1% improvement; 1,< or =25% improvement; 2, 26-50% improvement; 3, 51-75% improvement; and 4, > or =75% improvement. At five treatments, the excimer laser-treated patches had an average score of 0.26, compared with 0.04 for patches treated with NBUVB phototherapy. A slightly higher repigmentation (p>0.05) in the excimer treated area was thus observed. At 10, 15, or 20 treatments, the differences between the average scores were significant: 0.83, 1.17, and 1.39 for the excimer-treated patches, and 0.17, 0.30, and 0.74 for the NBUVB phototherapy-treated areas (p<0.05). In conclusion, the 308-nm excimer laser appears to be more effective than NBUVB phototherapy, as it produces more rapid and profound repigmentation.     

High-throughput sorting and analysis of human sperm with a ring-shaped laser trap

Sperm motility is an important concept in fertility research. To this end, single spot laser tweezers have been used to quantitatively analyze the motility of individual sperm. However, this method is limited with throughput (single sperm per spot), lacks the ability of in-situ sorting based on motility and chemotaxis, requires high laser power (hundreds of milliWatts) and can not be used to dynamically monitor changes in sperm swimming behavior under the influence of a laser beam. Here, we report a continuous 3-D ring-shaped laser trap which could be used for multi-level and high-throughput (tens to hundred sperm per ring) sperm sorting based on their motility and chemotaxis. Under a laser power of only tens of milliWatts, human sperm with low to medium velocity are slowed down, stopped, or forced to change their trajectories to swim along the ring due to the optical gradient force in the radial direction. This is the first demonstration of parallel sperm sorting based on motility with optical trapping technology. In addition, by making the sperm swimming along the circumference of the ring, the effect of laser radiation, optical force and external obstacles on sperm energetics are investigated in a more gentle and quantitative way. The application of this method could be extended to motility and bio-tropism studies of other self-propelled cells, such as algae and bacteria.     

Analysis of Odontoblast Gene Expression Using a Novel approach,Laser Capture Microdissection

Studying the mechanisms of molecular interactions in developing tissues demands sensitive molecular biological in vivo and in vitro techniques. Laser capture microdissection (LCM) allows for the isolation of mRNA in histological sections even from single cells, thus enabling the identification of in vivo gene expression products in closely circumscribed tissue areas. The aims of this study were to assess the optimal fixation, processing, and staining conditions to retrieve RNA from microdissected odontoblasts. Fluorometric assays and RT-PCR analysis of &#102 1(I) collagen, dentin sialophosphoprotein (Dspp), and osteocalcin (OC) confirmed that the total RNA isolated from day 0 and day 3 captured odontoblasts was sufficient in quantity and quality. Our results indicate that individual odontoblasts obtained by LCM are morphologically intact and chemically unaltered, allowing accurate molecular and biochemical analyses.     

Laser Doppler flowmetry: characteristics of a modified single-fibre technique

The single-fibre percutaneous laser Doppler technique has been used in previous studies of intramuscular blood flow. This method facilitates studies of blood flow in deep tissue volumes and minimises the tissue trauma. The technique has been further developed with the aim of improving the signal quality. This has been accomplished by modifying the geometry of the fibre tip. By melting the fibre core material, lenses of different shapes are formed. Flat, spherical and ‘pears-type tips have been manufactured and are evaluated theoretically and experimentally. The paraxial theory cannot accurately predict the position of zones of highest irradiance. Therefore, a ray-tracing program has been developed in the C language, by means of which some of the optical properties of the modified fibre tips can be simulated. Isoirradiance graphs and beam profiles are calculated for the three different fibre tips. Measured and calculated irradiance curves are used for evaluation of the properties of the ray-tracing model. The three types of fibre tips are also evaluated and compared in flow models. The sphere and pear-type probes show a higher flow sensitivity than the flat-end type. These improvements in flow sensitivity are interpreted as being related to the larger, strongly irradiated tissue volumes in front of the fibres. Intramuscular measurements with the pear-type probe show high sensitivities to induced blood flow changes.     

Measurements of steady turbulent flow through a rigid simulated collapsed tube

Axial and transverse components of liquid velocity are measured by laser Doppler anemometer in a perspex tube that has been deformed at one point to resemble the shape of the throat of a partially collapsed flexible tube, conveying fluid while being compressed externally. The Reynolds number is 5900. The flow downstream of the throat consists of two side-jets with reverse flow extending all across the cross-section between them. The jets spread out around the central retrograde-flow zone, initially forming crescents of high-speed forward flow and then, at three diameters downstream, an almost complete annulus of forward flow around a central zone of lower-speed but now forward flow. Comparison is made between the features of this turbulent flow and those of a previously investigated laminar flow through the same geometry. In both, retrograde flow ceases between two and three diameters downstream of the centre of the throat. However, the laminar flow is annular at three diameters downstream, whereas here the jets remain influential at that station. The maximum normalised turbulence intensity exceeds 1.35.     

双波长多通道激光针灸仪的设计与实现

目的 利用弱激光的生物刺激效应,针对中医针灸穴位配伍的临床应用特点,在中医针灸理论指导下设计一种双波长多通道激光针灸仪.方法 采用单片机与半导体激光器设计硬件电路,以实现仪器的基本功能,并设计相应的上位机软件.结果 所设计的激光针灸仪可对多个穴位同时进行相同或不同激光参数(波长、功率密度、连续/脉冲)的激光针灸治疗,每个通道均可输出635、808 nm两种波长的激光,且激光功率连续可调.结论 双波长多通道激光针灸仪实现了对针刺疗法中提、插等手法以及艾灸疗法中小炷、中炷、大炷等灸法的模拟,可满足针灸临床治疗中对穴位配伍、量化治疗参数及电子病历管理等多方面需求,操作简单,使用方便,具有良好的临床应用价值.     

Simulation of laser tomoscopy in a heterogeneous biological medium

A Monte Carlo model has been developed to study the propagation of an ultrashort light pulse through a heterogeneous thick biological specimen. A circular blood vessel is moved within a tissular slab to simulate biological specimen scanning using a picosecond laser source and a collimated ultrafast multichannel opticl shutter. Features of the transmitted light are computed for each position of the blood vessel. The computer program gives an account of the transmitted photons, the flight time which does not exceed straightforward crossing time plus time gate of known duration. A small blood vessel (radius R=2 mm) placed in a 40 mm thick slab is easily located when a time gate of 10 ps duration is employed. Such a time gate also allows the detection of a middle-sized vessel (R=4 mm) embedded in a thicker sample (80 mm). The contrast computed for the transmittance profile is greatly improved when a time gate is used. In addition, shifting of the blood vessel towards the unilluminated side of the sample decreases the contrast. We demonstrate that the time selection process may provide a substantial improvement to the laser tomoscopy technique when used for imaging biological media.     

Maxwell's equations-based dynamic laser–tissue interaction model

Since its invention in the early 1960s, the laser has been used as a tool for surgical, therapeutic, and diagnostic purposes. To achieve maximum effectiveness with the greatest margin of safety it is important to understand the mechanisms of light propagation through tissue and how that light affects living cells. Lasers with novel output characteristics for medical and military applications are too often implemented prior to proper evaluation with respect to tissue optical properties and human safety. Therefore, advances in computational models that describe light propagation and the cellular responses to laser exposure, without the use of animal models, are of considerable interest. Here, a physics-based laser–tissue interaction model was developed to predict the dynamic changes in the spatial and temporal temperature rise during laser exposure to biological tissues. Unlike conventional models, the new approach is grounded on the rigorous electromagnetic theory that accounts for wave interference, polarization, and nonlinearity in propagation using a Maxwell's equations-based technique.     

Laser-Perforated Membranous Biomaterials Induced Pore Size-Dependent Bone Induction When Used as a New BMP Carrier

Previously we found that laser perforation of a collagen membrane (35 &#119 m thickness, Koken Co., Tokyo) produced an effective bone morphogenetic protein (BMP) carrier, if the created pore sizes were larger than 0.5 mm. In this study we applied the same technique to create pores of 0.2 and 1.0 mm in a thicker (1.2 mm thickness) porous biodegradable membrane made of polylactic acid and an &#108 -caprolactone copolymer (PLA-CL) to obtain an effective membranous BMP carrier with higher mechanical strength. Pieces of PLA-CL (0.5 &#50 1.0 &#50 0.12 cm) combined with rhBMP-2 (5 &#119 g) were implanted subcutaneously into rats and processed for analyses at 1-3 weeks. The laser-perforated PLA-CL membranes equipped with 1.0 mm pores induced mineralization beginning from the margins of the pores judging from the X-ray patterns, but bone formation seemed to proceed irregularly inside the pores. In the perforated PLA-CL membrane with 1.0-mm pores bone formation did not significantly increase compared with the nonperforated one. This was due to the fact that the PLA-CL membrane was already a porous structure (85% porosity). In contrast with laser-perforated PLA-CL 0.2 mm pores, bone was induced on the collagen fibers and fiber bundles inside the pores. The different patterns of bone formation between the PLA-CL membranes with 1.0 and 0.2 mm pores seemed to be related to the active formation of perpendicular collagen fibers through the 0.2 mm pores.     

Retinoblastoma: A Three-Year-Study at a Brazilian Medical School Hospital

OBJECTIVE:

To present the characteristics and treatment outcomes of patients with retinoblastoma.

METHODS:

A retrospective case series was conducted to review the records of all new patients diagnosed with retinoblastoma between 2003 and 2005. Eyes with early disease, or advanced disease with potential vision were treated with chemotherapy (carboplatin and etoposide) in conjunction with early local therapy (laser or cryo). Radiotherapy was used in cases where the disease did not respond to the above protocols or in recurrent cases. Eyes in the late stage of disease with no potential vision in the initial examination or eyes and where conservative treatment had failed were enucleated.

RESULTS:

In total, we reviewed 28 new cases of retinoblastoma, 15 of which were unilateral and 13 of which were bilateral (46%). These data correspond to a mean of 9.3 new cases per year (0.77 case/month). The mean age at diagnosis was 33.8 months for unilateral cases, and 19.15 months for bilateral cases (p=0.015). Leucocoria was the major presenting symptom (75%). All but one patient with unilateral disease had the affected eye enucleated due to advanced disease (mean follow-up: 39.91 months). Among the 13 bilateral cases, 13 eyes (50%) were enucleated, 11 eyes (42.4%) were saved with chemotherapy in conjunction with local therapy and 2 eyes (7.6%) were saved using external beam radiotherapy (mean follow-up: 41.91 months). In unilateral and bilateral disease, pathology data revealed choroid involvement in 50% and 30%, respectively, and optic nerve invasion in 92% and 50%, respectively.

CONCLUSION:

In this population, retinoblastoma was diagnosed too late and most eyes were consequently enucleated. In cases with bilateral disease, half of the eyes were preserved.     

Diffuse Unilateral Subacute Neuroretinitis in a Healthy Korean Male: The First Case Report in Korea

A 52-yr-old male was referred for progressive visual loss in the left eye. The decimal best-corrected visual acuity (BCVA) was 0.01. Fundus examination revealed diffuse retinal pigment epithelial degeneration, focal yellow-white, infiltrative subretinal lesion with fuzzy border and a live nematode within the retina. Diffuse unilateral subacute neuroretinitis (DUSN) was diagnosed and the direct laser photocoagulation was performed to destroy the live nematode. During eight months after treatment, BCVA gradually improved to 0.2 along with the gradual restoration of outer retinal layers on SD-OCT. We report on the first case of DUSN in Korea. DUSN should be included in the differential diagnosis of unexplained unilateral visual loss in otherwise healthy subjects.

Graphical Abstract

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