Low-level laser (light) therapy (LLLT) has been known since 1967 but still remains controversial due to incomplete understanding of the basic mechanisms and the selection of inappropriate dosimetric parameters that led to negative studies. The biphasic dose-response or Arndt-Schulz curve in LLLT has been shown both in vitro studies and in animal experiments. This review will provide an update to our previous (Huang et al. 2009) coverage of this topic. In vitro mediators of LLLT such as adenosine triphosphate (ATP) and mitochondrial membrane potential show biphasic patterns, while others such as mitochondrial reactive oxygen species show a triphasic dose-response with two distinct peaks. The Janus nature of reactive oxygen species (ROS) that may act as a beneficial signaling molecule at low concentrations and a harmful cytotoxic agent at high concentrations, may partly explain the observed responses in vivo. Transcranial LLLT for traumatic brain injury (TBI) in mice shows a distinct biphasic pattern with peaks in beneficial neurological effects observed when the number of treatments is varied, and when the energy density of an individual treatment is varied. Further understanding of the extent to which biphasic dose responses apply in LLLT will be necessary to optimize clinical treatments.

/pdf/biphasic-dose-response-in-low-level-light-therapy-an-update-1z4xkwth46.pdf

Biphasic dose response in low level light therapy – an update

Cancer cells produce high levels of reactive oxygen species (ROS) that lead to a state of increased basal oxidative stress. Since this state of oxidative stress makes cancer cells vulnerable to agents that further augment ROS levels, the use of pro-oxidant agents is emerging as an exciting strategy to selectively target tumor cells. Natural products have provided a significant contribution to the development of several drugs currently used in cancer chemotherapy. Although many natural products are known to affect the redox state of the cell, most studies on these compounds have focused on their antioxidant activity instead of on their pro-oxidant properties. This article provides an overview of natural products with pro-oxidant and anticancer activities, with special focus on plant secondary metabolites, and discusses their possible use as cancer chemotherapeutic agents.

/pdf/pro-oxidant-natural-products-as-anticancer-agents-2pad3sgpcx.pdf

Pro-Oxidant Natural Products as Anticancer Agents

This is the 30th annual review of the application of atomic spectrometry to the chemical analysis of environmental samples. This Update refers to papers published approximately between August 2013 and July 2014 and continues the series of Atomic Spectrometry Updates (ASUs) in environmental analysis that should be read in conjunction with other related ASUs in the series, namely: clinical and biological materials, foods and beverages, advances in atomic spectrometry and related techniques, elemental speciation,X-ray fluorescence spectrometry, and the analysis of metals, chemicals and functional materials. In the field of air analysis, highlights within this review period included: the use of 3D printing technology for the rapid prototyping of new air sampler components; single particle ICP-MS studies; use of a new triple-quadrupole ICP-MS for the analysis of radioactive species and the use of FEG-SEM and IBA for the analysis of gun-shot residues. In the field of water analysis, methods continue to be developed: for the extraction and preconcentration of elements; speciation of As, Cr, Hg and Sb forms and determination of elemental constituents in colloidal and NP fractions. Instrumental developments reported include the use of MC-ICP-MS for isotopic tracer studies and a review of XRF techniques and associated preconcentration procedures for trace element analysis. Many articles featuring the analysis of plants and soils appeared but, as usual, most focused on environmental applications rather than the advancement of atomic spectrometry. There have, however, been interesting developments, such as the almost bewildering increase in types of micro-extraction for analyte preconcentration and the resurgence of CS-AAS. Clearly LIBS is maturing rapidly, with soil analysis becoming more routine in nature. Also notable was the way the accident at the Fukishima-Daiichi nuclear power plant triggered development of analytical methods for the assessment of contamination in the surrounding area. Recent research indicates that geological applications still drives many of the instrumental and methodological advances in LA-ICP-MS. Fundamental studies continue to shed light on the processes involved and hence ways of improving the analysis of laser-produced aerosols. The preparation of NP powders for the production of matrix-matched RMs for microanalytical techniques such as LA-ICP-MS and SIMS showed great promise for addressing one of the major issues when analysing geological materials by these techniques. Steady advances in MC-ICP-MS methodology is feeding through to applications in isotope geochemistry, while new SIMS instrumentation is being directed towards probing fine growth structures in biogenic carbonates and inferring past climate conditions from their geochemistry. Feedback on this review is most welcome and the review coordinator can be contacted using the email address provided.

/pdf/atomic-spectrometry-update-a-review-of-advances-in-2r8uzbiose.pdf

Atomic spectrometry update – a review of advances in environmental analysis

Juglone, a naphthoquinone from walnut, exerts cytotoxic and genotoxic effects against cultured melanoma tumor cells

Photobiomodulation (PBM) therapy, previously known as low-level laser therapy, was discovered more than 50 years ago, yet there is still no agreement on the parameters and protocols for its clinical application. Some groups have recommended the use of a power density less than 100  mW/cm2 and an energy density of 4 to 10  J/cm2 at the level of the target tissue. Others recommend as much as 50  J/cm2 at the tissue surface. The wide range of parameters that can be applied (wavelength, energy, fluence, power, irradiance, pulse mode, treatment duration, and repetition) in some cases has led to contradictory results. In our review, we attempt to evaluate the range of effective and ineffective parameters in PBM. Studies in vitro with cultured cells or in vivo with different tissues were divided into those with higher numbers of mitochondria (muscle, brain, heart, nerve) or lower numbers of mitochondria (skin, tendon, cartilage). Graphs were plotted of energy density against power density. Although the results showed a high degree of variability, cells/tissues with high numbers of mitochondria tended to respond to lower doses of light than those with lower number of mitochondria. Ineffective studies in cells with high mitochondrial activity appeared to be more often due to over-dosing than to under-dosing.

https://www.spiedigitallibrary.org/journals/Journal-of-Biomedical-Optics/volume-23/issue-12/120901/Review-of-light-parameters-and-photobiomodulation-efficacy--dive-into/10.1117/1.JBO.23.12.120901.pdf

Review of light parameters and photobiomodulation efficacy: dive into complexity

Direct spectro-chemical analysis of trace elements in complex matrices like minerals and soil is usually difficult because of possible interference from the intense background spectrum of the major components generated in the plasma. Optimization of the Laser Induced Breakdown Spectroscopy (LIBS) technique is essential for routine analysis of such samples. In the present work, we have shown that low detection limits can be achieved for trace elements like copper, zinc, and calcium in soil samples by using high resolution echelle spectrographs coupled to the LIBS system, and eliminating the background by subtraction of a suitable matrix “blank” spectrum. It is also shown that the LOD (limits of detection) can be further reduced by suitable data processing techniques like signal addition from multiple lines provided by the wide-range echelle system and use of correlation function calculation with a pure element spectrum. The validity of our LIBS technique was confirmed by conventional Atomic Absorption Spectroscopy (AAS) analysis for the same analyte after pre-concentration.

Analysis of trace elements in complex matrices (soil) by Laser Induced Breakdown Spectroscopy (LIBS)

Cytotoxic, genotoxic and oxidative stress induced by 1,4-naphthoquinone in B16F1 melanoma tumor cells.

We report the design and development of an optical fiber probebased Helium–Neon (He–Ne) low-level laser therapy system for tissue regeneration. Full thickness excision wounds on Swiss albino mice of diameter 15 mm were exposed to various laser doses of 1, 2, 3, 4, 6, 8 and 10 J cm )2 of the system with appropriate controls, and 2 J cm )2 showing optimum healing was selected. The treatment schedule for applying the selected laser dose was also standardized by irradiating the wounds at different postwounding times (0, 24 and 48 h). The tissue regeneration potential was evaluated by monitoring the progression of wound contraction and mean wound healing time along with the hydroxyproline and glucosamine estimation on wound ground tissues. The wounds exposed to 2 J cm )2 immediately after wounding showed considerable contraction on days 5, 9, 12, 14, 16 and 19 of postirradiation compared with the controls and other treatment schedules, showing significant ( P< 0.001) decrease in the healing time. A significant increase in hydroxyproline and glucosamine levels was observed for the 2 J cm )2 irradiation group compared with the controls and other treatment groups. In conclusion, the wounds treated with 2 J cm )2 immediately after the wounding show better healing compared with the controls.

Development and Evaluation of Fiber Optic Probe‐based Helium–Neon Low‐level Laser Therapy System for Tissue Regeneration—An In Vivo Experimental Study

The present study aimed at evaluating the anticancer and radiosensitizing potential of juglone against a chemoresistant and radioresistant tumor (B16F1 melanoma) growing on C57BL/6J mice. Volume doubling time, growth delay, and median survival were used to assess the in vivo anticancer and radiosensitizing potential of juglone. In vitro radiosensitizing potential of juglone was studied using clonogenic, comet, and reactive oxygen species induction assays. Treatment of tumor-bearing mice with sublethal doses of juglone caused a dose-dependent inhibition of tumor growth as evident from the growth delay and median survival values. Comet assay using tumor tissue and blood showed differential toxicity of juglone, where higher levels of DNA damage was seen in tumor tissue compared with blood cells. Pretreatment of tumor-bearing mice with optimum dose of juglone before radiation resulted in significant tumor growth inhibition compared with radiation alone. From the clonogenic assay, the authors observed a sensitization enhancement ratio of 1.37 for the combination treatment compared with radiation alone. Furthermore, comet assay studies revealed the potential of juglone to enhance the radiation-induced DNA damage and cause a delay in its repair. Juglone pretreatment before radiation also resulted in a significant elevation in the intracellular reactive oxygen species levels compared with radiation alone. In conclusion, the results of this study show the potential of juglone to inhibit the growth of melanoma in vivo. The study also revealed the potential of juglone to augment the radiation-induced cell death of melanoma cells, which may be attributed to oxidative stress-mediated DNA damage and its delayed repair.

https://journals.sagepub.com/doi/pdf/10.1177/1534735411403477

Kiran Aithal

Papers

Juglone, a naphthoquinone from walnut, exerts cytotoxic and genotoxic effects against cultured melanoma tumor cells

Analysis of trace elements in complex matrices (soil) by Laser Induced Breakdown Spectroscopy (LIBS)

Cytotoxic, genotoxic and oxidative stress induced by 1,4-naphthoquinone in B16F1 melanoma tumor cells.

Development and Evaluation of Fiber Optic Probe‐based Helium–Neon Low‐level Laser Therapy System for Tissue Regeneration—An In Vivo Experimental Study

Tumor growth inhibitory effect of juglone and its radiation sensitizing potential: in vivo and in vitro studies.