Light sheet microscopy for histopathology applications

Light sheet microscopy (LSM) is an evolving optical imaging technique with a plane illumination for optical sectioning and volumetric imaging spanning cell biology, embryology, and in vivo live imaging. Here, we focus on emerging biomedical applications of LSM for tissue samples. Decoupling of the light sheet illumination from detection enables high-speed and large field-of-view imaging with minimal photobleaching and phototoxicity. These unique characteristics of the LSM technique can be easily adapted and potentially replace conventional histopathological procedures. In this review, we cover LSM technology from its inception to its most advanced technology; in particular, we highlight the human histopathological imaging applications to demonstrate LSM's rapid diagnostic ability in comparison with conventional histopathological procedures. We anticipate that the LSM technique can become a useful three-dimensional imaging tool for assessing human biopsies in the near future.

Blocking or enhancing effects of some basic emollients in UVA penetration

Abstract: Background: Topical agents used in combination with phototherapy or photochemotherapy may have both blocking or enhancing effects in ultraviolet rays. Objective: In this in vivo study, the effects of topical petrolatum, basis cream, glycerine, and olive oil on the transmission of ultraviolet A radiation were investigated. Methods: A test was performed to determine the minimal phototoxic dose on 29 volunteers with only psoralen plus ultraviolet A (PUVA) and then the same test was repeated with white petrolatum, basis cream, glycerine, olive oil, and sunscreen (0.3cc/25cm2). The effects of each agent on the minimal phototoxic dose were determined after 72 h. Results: When compared to pure PUVA, there was a statistically significant increase in the mean minimal phototoxic dose values by the application of white petrolatum (P = 0.011), but there was no significant increase or decrease in the mean minimal phototoxic dose values after the application of basis cream (P = 0.326), glycerine (P = 0.611) or olive oil (P = 0.799). Study limitations: Low number of patients Conclusion: The application of white petrolatum, which has a blocking effect, and also of basis cream immediately before PUVA therapy should not be recommended. Although we specify that glycerine and maybe olive oil can be used before photochemotherapy, there is a need for further research in larger series.

Accelerated ecotoxicity of photoreactive nanoparticles on Moina macrocopa

Zinc oxide nanoparticles (ZnO NPs) and titanium dioxide nanoparticles (TiO2 NPs) are well known as photoreactive nanoparticles (NPs). Various phototoxicities of ZnO NPs and TiO₂ NPs were reported on several organisms. It was still necessary to evaluate the toxicity of photoreactive ZnO NPs and TiO₂ NPs due to species-specific effects under various irradiation conditions. We compared the acute toxicity of Moina macrocopa under visible, ultraviolet (UV) A, and B irradiations, according to the Organization for Economic Cooperation and Development guidelines for the testing of chemicals (Test No. 202). The sensitivity of ZnO NPs for M. macrocopa was UVB>UVA>visible light irradiation. There were no significant lethal and immobile effects of TiO₂ NPs on juveniles under all irradiations and in the tested concentrations of TiO₂ NPs. Photoreactive NPs have a potential and accelerated toxicity on organisms in the ambient environments.

Accelerated ecotoxicity of photoreactive nanoparticles on Moina macrocopa

Zinc oxide nanoparticles (ZnO NPs) and titanium dioxide nanoparticles (TiO2 NPs) are well known as photoreactive nanoparticles (NPs). Various phototoxicities of ZnO NPs and TiO₂ NPs were reported on several organisms. It was still necessary to evaluate the toxicity of photoreactive ZnO NPs and TiO₂ NPs due to species-specific effects under various irradiation conditions. We compared the acute toxicity of Moina macrocopa under visible, ultraviolet (UV) A, and B irradiations, according to the Organization for Economic Cooperation and Development guidelines for the testing of chemicals (Test No. 202). The sensitivity of ZnO NPs for M. macrocopa was UVB>UVA>visible light irradiation. There were no significant lethal and immobile effects of TiO₂ NPs on juveniles under all irradiations and in the tested concentrations of TiO₂ NPs. Photoreactive NPs have a potential and accelerated toxicity on organisms in the ambient environments.

Eccrine Squamous Syringometaplasia Associated with Pelubiprofen Therapy

Eccrine squamous syringometaplasia (ESS) is a histologically distinctive skin eruption occurring predominantly in acral or intertriginous areas presenting as erythematous macules, papules or patches. The etiology of ESS remains unclear, but it is usually reported in patients receiving chemotherapy for various malignant neoplasms. To date, only two cases of ESS associated with non-steroidal anti-inflammatory drugs (NSAIDs), which has distinctive clinical features and pathogenesis, have been reported in the literature. Herein, we report a rare and interesting case of ESS associated with pelubiprofen, a recently developed NSAID, which appeared after pelubiprofen therapy and resolved spontaneously after discontinuing the medication.

Photodynamic Therapy for Hilar Bile Duct Cancer / 대한췌담도학회지

Hilar cholangiocarcinoma is a fatal malignancy leading to high mortality rate despite recent therapeutic advances, and the photodynamic therapy has been noted as an emerging palliative strategy for the hilar cholangiocarcinoma. Photodynamic therapy is the treatment selectively destructing cancer tissue through the laser beam irradiation with particular wavelengths. Photosensitizer administered before the treatment is accumulated in malignant tissue, and activated in the limits of those wavelengths. The procedure is performed under percutaneous transhepatic biliary drainage or endoscopic retrograde cholangiopancreatography, and more appropriate for the periductal infiltrating type rather than mass-forming type of cholangiocarcinoma due to the shallow penetrating depth (<4.5 mm). Recent investigations demonstrated the survival gain of 4-6 months in patients with cholangiocarcinoma when it is added to palliative biliary drainage. In addition, newly developed 3rd generation photo sensitizer has enabled longer therapeutic effect with less skin phototoxicity than before. However, there are still some limitations should be concerned, including lack of large-scaled prospective studies, shallow penetrating depth of tumoricidal effects, lack of treatment response measure, and relatively expensive cost. Addressing these matters through the larger prospective studies or technical improvement may lead new era of photodynamic therapy not only for the palliative purpose but also in the therapeutic field of cholangiocarcinoma.

Phototoxic effect of blue light on the planktonic and biofilm state of anaerobic periodontal pathogens

PURPOSE: The purpose of this study was to compare the phototoxic effects of blue light exposure on periodontal pathogens in both planktonic and biofilm cultures. METHODS: Strains of Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, and Porphyromonas gingivalis, in planktonic or biofilm states, were exposed to visible light at wavelengths of 400.520 nm. A quartz-tungsten-halogen lamp at a power density of 500 mW/cm2 was used for the light source. Each sample was exposed to 15, 30, 60, 90, or 120 seconds of each bacterial strain in the planktonic or biofilm state. Confocal scanning laser microscopy (CSLM) was used to observe the distribution of live/dead bacterial cells in biofilms. After light exposure, the bacterial killing rates were calculated from colony forming unit (CFU) counts. RESULTS: CLSM images that were obtained from biofilms showed a mixture of dead and live bacterial cells extending to a depth of 30-45 microm. Obvious differences in the live-to-dead bacterial cell ratio were found in P. gingivalis biofilm according to light exposure time. In the planktonic state, almost all bacteria were killed with 60 seconds of light exposure to F. nucleatum (99.1%) and with 15 seconds to P. gingivalis (100%). In the biofilm state, however, only the CFU of P. gingivalis demonstrated a decreasing tendency with increasing light exposure time, and there was a lower efficacy of phototoxicity to P. gingivalis as biofilm than in the planktonic state. CONCLUSIONS: Blue light exposure using a dental halogen curing unit is effective in reducing periodontal pathogens in the planktonic state. It is recommended that an adjunctive exogenous photosensitizer be used and that pathogens be exposed to visible light for clinical antimicrobial periodontal therapy.

Selective Effects of Curcumin on CdSe/ZnS Quantum-dot-induced Phototoxicity Using UVA Irradiation in Normal Human Lymphocytes and Leukemia Cells

Quantum dots (QDs) have received considerable attention due to their potential role in photosensitization during photodynamic therapy. Although QDS are attractive nanomaterials due to their novel and unique physicochemical properties, concerns about their toxicity remain. We suggest a combination strategy, CdSe/ZnS QDs together with curcumin, a natural yellow pigment from turmeric, to reduce QD-induced cytotoxicity. The aim of this study was to explore a potentially effective cancer treatment: co-exposure of HL-60 cells and human normal lymphocytes to CdSe/ZnS QDs and curcumin. Cell viability, apoptosis, reactive oxygen species (ROS) generation, and DNA damage induced by QDs and/or curcumin with or without ultraviolet A (UVA) irradiation were evaluated in both HL-60 cells and normal lymphocytes. In HL-60 cells, cell death, apoptosis, ROS generation, and single/double DNA strand breaks induced by QDs were enhanced by treatment with curcumin and UVA irradiation. The protective effects of curcumin on cell viability, apoptosis, and ROS generation were observed in normal lymphocytes, but not leukemia cells. These results demonstrated that treatment with QD combined with curcumin increased cell death in HL-60 cells, which was mediated by ROS generation. However, curcumin acted as an antioxidant in cultured human normal lymphocytes.

Phototoxicity activity of Psoralea drupacea L. using Atremia salina bioassay system

Phototoxicity is a kind of dermatitis that is activated by exposure to ultraviolet light following the administration of some drugs or natural products. Artemia salina [A. salina] [brine shrimp] has been effectively applied for toxicity testing and is perfect for biological screening of many chemicals for simultaneous evaluation of toxicity and phototoxicity. The objective of this study was to investigate the phototoxic activitiy of the methanolic extract and chloroform and CH3OH/H2O2 fraction of Psoralea drupacea [P. drupacea]. The phototoxic effect of the methanolic extract, chloroform and CH3OH/H2O2 fractions of P. drupacea was evaluated using A. salina bioassay system. Different concentrations of methanolic extract and fractions of P. drupacea were added to the plate of one-day old larvae followed by exposure to UV radiation at 366 nm in three different exposure times [0, 4 and 20 h]. Mortality was determined 24h after the start of the irradiation. The value of LC[50] of P. drupacea methanolic extract and methoxalen as positive control were 0.64 and 3.5x10-4 mg/ml, respectively. P. drupacea methanolic extract and chloroform fraction demonstrated phototoxic activity after 4 h radiation. The result showed that P. drupacea methanolic extract and chloroform fraction have phototoxicity in A. salina bioassay system and their toxic effect is related to phototoxic constituents such as psoralen

Retinal Changes in White Rabbits after Exposure to the Light of an Operating Microscope

PURPOSE: This study was performed to investigate the potential damage to white rabbit retinas caused by an operating microscope light. METHODS: A total of 18 white rabbits were exposed to the light of an operating microscope for 60 minutes. Fundus examination, fluorescein angiography (FAG), and electroretinogram (ERG) were performed before exposure and 1 hr, 1 day, 7 days and 14 days afterward to allow for serial comparisons. Light and electron microscopic examinations were performed to evaluate the changes in the rabbit retinas over time. RESULTS: Signs of retinal damage upon fundus examination and FAG were not found before or after exposure to the light of an operating microscopy. ERG, however, showed significant reduction in the dark-adapted rod response 1 hour after light exposure, and significant decline in the amplitude of the maximal combined response a- and b-wave 1 day after light exposure in the rabbit retinas. ERG findings returned to the pre-exposure level after 2 weeks. Ultrastructural injury to the photoreceptor outer segments and the retinal pigmented epithelium, observed using transmission electron microscopy, recovered to the pre-exposure state after 2 weeks. CONCLUSIONS: The risk of retinal damage should be considered as an early result of exposure to the light of an operating microscope, even in normal retinal findings.

Reações aos diferentes pigmentos de tatuagens: relato de dois casos / Reactions to the different pigments in tattoos: a report of two cases

A tatuagem é definida como deposição de pigmento intencional ou acidental na pele. Os pigmentos têm sido associados a diversas dermatoses, como a dermatite de contato alérgica, a dermatite liquenoide e as reações fotoinduzidas, granulomatosas, sarcoídeas e pseudolinfomatosas. Enfocam-se os diversos tipos de reações aos pigmentos e a importância de reconhecê-los clinicamente. São relatados dois casos: um de dermatite liquenoide sobre o pigmento vermelho e outro de pseudolinfoma sobre os pigmentos vermelho e lilás e de reação fotoinduzida sobre o amarelo. A remoção geralmente requer múltiplos tratamentos, e a maioria não retira as cores completamente.

Tattoos are defined as the intentional or accidental deposit of pigment into the skin. These pigments have been associated with various dermatoses such as allergic contact dermatitis, lichenoid dermatitis, photoinduced reactions, and granulomatous, sarcoid and pseudolymphomatous reactions. The objective of this report was to describe the various types of reactions to pigments and the importance of recognizing them clinically. Two cases are reported: one of lichenoid dermatitis resulting from a reaction to the red pigment of a tattoo and the other of a pseudolymphoma resulting from a reaction to red and lilac pigments and a photo-induced reaction to a yellow pigment. Removal generally requires multiple forms of treatment, most of which fail to remove the colors completely.

Transmission electron microscopy of the preclinical phase of experimental phytophotodermatitis

OBJECTIVE: To examine the epidermis in induced phytophotodermatitis using transmission electron microscopy in order to detect histologic changes even before lesions are visible by light microscopy. INTRODUCTION: In the first six hours after the experimental induction of phytophotodermatitis, no changes are detectable by light microscopy. Only after 24 hours can keratinocyte necrosis and epidermal vacuolization be detected histologically, and blisters form by 48 hours. METHODS: The dorsum of four adult rats (Rattus norvegicus) was manually epilated. After painting the right half of the rat with the peel juice of Tahiti lemon, they were exposed to sunlight for eight minutes under general anesthesia. The left side was used as the control and exposed to sunlight only. Biopsies were performed immediately after photoinduction and one and two hours later, and the tissue was analyzed by transmission electron microscopy. RESULTS: No histological changes were seen on the control side. Immediately after induction, vacuolization in keratinocytes was observed. After one hour, desmosomal changes were also observed in addition to vacuolization. Keratin filaments were not attached to the desmosomal plaque. Free desmosomes and membrane ruptures were also seen. At two hours after induction, similar changes were found, and granular degeneration of keratin was also observed. DISCUSSION: The interaction of sunlight and psoralens generates a photoproduct that damages keratinocyte proteins, leading to keratinocyte necrosis and blister formation. CONCLUSIONS: Transmission electron microscopy can detect vacuolization, lesions of the membrane, and desmosomes in the first two hours after experimental induction of phytophotodermatitis.

Desenvolvimento de nanopartículas fotossensibilizadoras / Development of photosensitizing nanoparticles

No presente trabalho são apresentadas a síntese e a caracterização estrutural, fotofísica, fotoquímica e fotoquímica e fotobiológica de nanopartículas contendo os fotossensibilizadores (FS) Azul de Metileno (AM) e Tionina. AM e Tionina incorporados nas nanopartículas sil-AM e sil-Tio pelo processo sol-gel. Nas nanopartículas Cab-Tio, Tionina foi ligada à superfície de sílica CabOsil® através de ligação covalente com reagentes bifuncionais. Todas as nanopartículas mostraram-se esféricas e com de diâmetro médio na faixa de 30 a 60nm. A imobilização dos FS induziu a agregação destes em extensões diferentes para cada tipo de nanopartícula. Foi observado que a maior presença de dímeros de FS leva à menor eficiência de geração de 1O2 Constatou-se que as nanopartículas sofrem pouca influência do meio, uma vez que os FS a elas ligadas não sofreram redução química por NADPH, nem supressão do estado tripleto por íons ascorbato e a supressão de fluorescência por íon brometo foi diminuída. Foi testado também o efeito do recobrimento destas nanopartículas com lipídios dioleilfosfatidil colina (DOPC) e fosfatidilglicerol (PG) e com Polietileno glicol (PEG). A adsorção das nanopartículas sobre membranas miméticas foi reduzida após os recobrimentos, resultado que foi explicado pelas interações de carga superficial (potencial zeta) e pela força de hidratação...

The establishment and assessment on cosmetic products using 3T3 mouse fibroblast neutral red uptake phototoxicity assay / 中华预防医学杂志

<p><b>OBJECTIVE</b>To establish the 3T3 mouse fibroblast neutral red uptake (NRU-PT) phototoxicity test method, and evaluate the practicality of the method in detecting potential phototoxicity of the cosmetic products.</p><p><b>METHODS</b>Fifteen phototoxic and 9 non-phototoxic chemicals were tested in our laboratories, the phototoxic potential of the test chemicals was evaluated in a prediction model in which either the photo irritation factor (PIF) or the mean photo effect (MPE) was compared with the coherence and sensitivity of the method. 20 kinds of functional cosmetics were detected and the results were analyzed by the 3T3 NRU-PT in vitro and Guinea pig skin phototoxicity test (in vivo).</p><p><b>RESULTS</b>Both PIF and MPE of the chemicals were highly reproduced, and the correlation between in vitro and in vivo data was almost perfect. All the non-phototoxic provided a negative result, while 14 of the 15 phototoxic tested chemicals gave clear positive results. For cosmetics, the correlation between in vitro and in vivo data was consistent.</p><p><b>CONCLUSION</b>The 3T3 NRU PT test was established successfully, it should be used as a good alternative method for assessing the phototoxic potential of the chemicals and cosmetics in China.</p>

study on the possible doxycycline-ginkgo biloba extract phototoxic interaction in mice

Doxycycline is considered as the most phototoxic drug in tetracycline group. Its phototoxic potential has been demonstrated in human being as well as in laboratory animals. The aim of the resent work was to evaluate the possible protective effect of Ginkgo biloba extract, against doxycycline-induced phototoxicity. The study was performed on Swiss albino mice. Doxycycline [400 mg/kg] was administered orally. Two dose levels of Ginkgo biloba extract were utilized [100 and 200 mg/kg p.o.]. Mice were exposed to UV-A radiation one hour after administration of doxycycline. UV-A radiation was directed to the animal's ears for 210 min. at a dose of 25 Jol/cm[2]. Immediately after irradiation, animals were given a single dose of Ginkgo biloba extract. Twenty four hours later, the erythmatous photoreaction was examined by the naked eye according to a score index. Edema was evaluated by measuring ear pinna thickness using digital micrometer. Ears were then excised and subjected to histopathological evaluation. The obtained results showed significant protection by Kingo biloba extract against doxycycline-induced phototoxicity. The protection was dose dependent, where each of erytherma and ear pinna thickness were reduced by 33% and 44%, and 28% and 39% following the low and high used doses of Ginkgo biloba extract, respectively

A Case of 5-fluorouracil-induced Phototoxicity / 대한피부과학회지

5-fluorouracil (5-FU) is an antimetabolite which prevents thymine synthesis and suppresses the utilization of preformed uracil. A variety of cutaneous reactions have been reported with the use of systemic 5-FU, the most common being photosensitivity. We report a case of 5-FU induced phototoxicity in a 73-year-old male. The patient had tender and slightly pruritic scaly and crusted erythema on sun-exposed areas. A biopsy revealed necrotic keratinocytes with epidermal degeneration. After the cessation of 5-FU, the skin lesions showed a marked improvement, and there was no further photosensitivity to the skin.