Principles of Lasers and Biophotonic Effects

Análise da eficácia do laser de baixa potência no tratamento da dor tendínea em ratos imunossuprimidos

O comprometimento do sistema imune, que pode ser apresentado por indivíduos com doenças crônicas, leva à baixa resposta imunológica. Um dos tratamentos utilizados para lesões agudas em tendões é o laser de baixa potência, contudo há uma lacuna em relação ao seu uso em imunodepressão. O objetivo do presente estudo foi analisar se o laser de baixa potência é eficaz para o tratamento da dor em ratos imunodeprimidos submetidos a trauma tendíneo. Foram utilizados 23 ratos, machos, da linhagem Wistar, divididos aleatoriamente em três grupos: grupo controle, placebo e laser. Os animais foram imunodeprimidos (por administração de Ciclosporina A) e submetidos à lesão no tendão calcâneo direito, com impacto de cerca de 0,40 J. Para o tratamento, utilizou-se laser de baixa potência, 670 nm, 30 mW e dose de 2 J/cm², durante 3 dias. A avaliação da dor foi realizada pelo teste de incapacidade funcional e por filamento de Von Frey digital. Os resultados apresentaram valores significativos para o grupo laser, com diminuição de dor funcional e da dor à pressão na superfície plantar e no local lesionado (tendão calcâneo direito). Portanto, concluiu-se que o laser de baixa potência é eficaz para reduzir a dor em ratos imunodeprimidos submetidos a trauma tendíneo.

Percutaneous treatment of intervertebral disc herniation

Interventional radiology plays a major role in the management of symptomatic intervertebral disc herniations. In the absence of significant pain relief with conservative treatment including oral pain killers and anti-inflammatory drugs, selective image-guided periradicular infiltrations are generally indicated. The precise control of needle positioning allows optimal distribution of steroids along the painful nerve root. After 6 weeks of failure of conservative treatment including periradicular infiltration, treatment aiming to decompress or remove the herniation is considered. Conventional open surgery offers suboptimal results and is associated with significant morbidity. To achieve minimally invasive discal decompression, different percutaneous techniques have been developed. Their principle is to remove a small volume of nucleus, which results in an important reduction of intradiscal pressure and subsequently reduction of pressure inside the disc herniation. However, only contained disc herniations determined by computed tomography or magnetic resonance are indicated for these techniques. Thermal techniques such as radiofrequency or laser nucleotomy seem to be more effective than purely mechanical nucleotomy; indeed, they achieve discal decompression but also thermal destruction of intradiscal nociceptors, which may play a major role in the physiopathology of discal pain. The techniques of image-guided spinal periradicular infiltration and percutaneous nucleotomy with laser and radiofrequency are presented with emphasis on their best indications.

Optical imaging in cancer research: basic principles, tumor detection, and therapeutic monitoring

Accurate and rapid detection of diseases is of great importance for assessing the molecular basis of pathogenesis, preventing the onset of complications, and implementing a tailored therapeutic regimen. The ability of optical imaging to transcend wide spatial imaging scales ranging from cells to organ systems has rejuvenated interest in using this technology for medical imaging. Moreover, optical imaging has at its disposal diverse contrast mechanisms for distinguishing normal from pathologic processes and tissues. To accommodate these signaling strategies, an array of imaging techniques has been developed. Importantly, light absorption, and emission methods, as well as hybrid optical imaging approaches are amenable to both small animal and human studies. Typically, complex methods are needed to extract quantitative data from deep tissues. This review focuses on the development of optical imaging platforms, image processing techniques, and molecular probes, as well as their applications in cancer diagnosis, staging, and monitoring therapeutic response.

Efeitos dos recursos eletrofísicos na osteoporose: uma revisão da literatura

OBJETIVO: Fazer uma revisão bibliográfica a respeito dos efeitos dos principais recursos eletrofísicos utilizados na aceleração do metabolismo ósseo e no tratamento da osteoporose. ANTECEDENTES: A Organização Mundial da Saúde (OMS) define a osteoporose como doença esquelética sistêmica caracterizada por diminuição da massa óssea e deterioração microarquitetural do tecido ósseo, com consequente aumento da fragilidade óssea e susceptibilidade à fratura. Vários tratamentos medicamentosos e não medicamentosos vêm sendo desenvolvidos na tentativa de aumentar a massa óssea e prevenir a osteoporose. Dentro desse contexto, os recursos eletrofísicos vêm tendo um papel de destaque, como recursos que apresentam um potencial osteogênico, capazes de estimular a proliferação de osteoblastos e biomodular o metabolismo ósseo. ESTRATÉGIA DE PESQUISA: Foram consultadas as bases de dados: The Cochrane Library, MEDLINE, Embase, LILACS, SciELO, referências dos artigos identificados, e contato com especialisas em laser, entre os anos de 1983 e 2009. CRITÉRIOS DE SELEÇÃO: Foram incluídos estudos experimentais e ensaios clínicos randomizados que avaliaram os efeitos dos recursos eletrofísicos na osteoporose. RECOMPILAÇÃO E ANÁLISE DE DADOS: Dois revisores selecionaram independentemente os estudos, avaliaram sua qualidade metodológica dos estudos e coletaram os dados. RESULTADOS: Todos os recursos eletrofísicos citados neste artigo se mostraram eficazes na estimulação do metabolismo ósseo. No entanto, a grande maioria dos estudos realizados evidenciam esses efeitos através de estudos in vitro e estudos experimentais com cobaias. Cabe ressaltar que trabalhos como esses são raros em seres humanos. Baseado nos achados desta revisão pode ser sugerido que os recursos eletrofísicios como o laser terapêutico, o ultrassom, campos eletromagnéticos e plataformas vibratórias são recursos que tem um potencial osteogênico entretanto mais estudos são necessários para definir os efeitos dos mesmos em humanos, bem como, protocolos mais eficazes de tratamento. CONCLUSÃO: A partir deste levantamento bibliográfico, fica evidente que os recursos eletrofísicos apresentam um grande potencial osteogênico, porém, a maior parte dos estudos é in vitro. São necessários mais estudos in vivo, definindo, assim, melhores parâmetros e doses, para que sejam utilizados no tratamento da osteoporose.

Lasers and the treatment of chronic periodontitis

For many intraoral soft-tissue surgical procedures the laser has become a desirable and dependable alternative to traditional scalpel surgery. However, the use of dental lasers in periodontal therapy is controversial. This article presents the current peer-reviewed evidence on the use of dental lasers for the treatment of chronic periodontitis.

Genotoxic effects of 1064-nm Nd:YAG and 532-nm KTP lasers on fibroblast cell cultures

BACKGROUND

Several different laser types are used in cutaneous surgery. The neodymium:yttrium-aluminium-garnet (Nd:YAG) and frequency-doubled Nd:YAG (KTP, potassium titanyl phosphate) lasers are widely used in dermatology.

OBJECTIVES

To investigate the possible genotoxic effects on fibroblasts of irradiation with a 1064-nm Nd:YAG laser and a 532-nm KTP laser.

METHODS

Fibroblast cell cultures were exposed to each of the lasers, using 10-mm spot size at 60 ms pulse duration with 10, 20, 40 J/cm(2) and 3, 6, 12 J/cm(2) fluences, respectively. Fibroblasts in passages 1-6 were used. During laser irradiation, 96-well microplate cultures were kept on a cooling block and transported on ice and in the dark, and processed immediately for single-cell gel electrophoresis (SCGE) assay (also known as a comet assay).

RESULTS

DNA damage was determined by computerized assessment of comet assay. There was increasing damage with increasing numbers of passages. For the Nd:YAG laser, the greatest damage occurred on passages 5 and 6, whereas the greatest damage appeared at passages 3 and 4 for KTP and returned to baseline at passages 5 and 6. Damage also increased with each dose increment for both wavelengths. At the highest dose for both wavelengths (Nd:YAG 40 J/cm(2) and KTP 12 J/cm(2)), damage was higher with the Nd:YAG laser.

CONCLUSIONS

Different patterns of cellular damage were seen for different cell-culture passages, treatment doses, and laser wavelengths. These dose ranges are generally used for the treatment of vascular and pigmented lesions and for rejuvenation purposes. As replicative ageing or cell senescence is one of the critical factors determining the extent of cell damage induced by laser therapy, these results may have important implications for clinical practice.

Verifiable CPD paper: laser-tissue interaction

The oral cavity is a unique and complex environment, where hard and soft tissues exist in close proximity, within bacteria-laden saliva. All oral tissues are receptive to laser treatment, but the biophysics governing laser-tissue interaction demands a knowledge of all factors involved in delivery of this modality; through this knowledge, correct and appropriate treatment can be delivered in a predictable manner.

Technical innovations and the evolution of endoscopic sinus surgery

Since the introduction of endoscopic sinus surgery, a number of significant technological advances, as well as an improved understanding of disease pathogenesis and management, have enabled major evolutions in surgical techniques. Modifications to surgical instruments, imaging, the development of the microdebrider, and other newer instrumentation have all contributed to the current level of patient success associated with endoscopic intranasal techniques. At the same time, it has become evident that anatomic variations are less important in the pathogenesis of chronic rhinosinusitis than was previously thought, and that ventilation alone is insufficient to resolve well-established disease. This paper reviews the changes that have occurred in endoscopic sinus surgery over the past 20 years since the techniques were first introduced into the United States, and the technologies that have enabled these changes and the development of extended endoscopic techniques. Continuing developments of interactive computer-guided surgery, endoscopic 3-dimensional imagery, robotics, and improved adjunctive therapies will further extend the role of endoscopic transnasal approaches to an expanded number of skull base and intracranial lesions.

Fractional Photothermolysis for Treatment of Poikiloderma of Civatte

Poikiloderma of Civatte refers to a change in the skin where there is atrophy, hyper- and hypopigmentation, and dilation of fine blood vessels (telangiectasia). These alterations often cause cosmetic disfigurement, most commonly in middle-aged or elderly women with a fair complexion. Several treatment modalities, based on the theory of selective photothermolysis, including argon lasers, KTP lasers, pulsed dye lasers, and intense pulsed light devices, have been used to treat this condition in the past. Clinical experience has shown that complete clearing is difficult to achieve. Moreover, depending on the modality used, adverse effects, such as scarring with irregular hypopigmentation, post-inflammatory hyperpigmentation, post-treatment purpura, mottled appearance, crusting, and erythema, have been reported. Multiple sessions with these treatments are usually necessary to obtain optimal clearing.