Melatonin improves ultraviolet B ‐induced oxidative damage and inflammatory conditions in cutaneous tissue of a diurnal I ndian palm squirrel F unambulus pennanti

Susceptibility to radiation adverse effects in veterans with Gulf War illness and healthy civilians

We evaluated whether veterans with Gulf War illness (VGWI) report greater ionizing radiation adverse effects (RadAEs) than controls; whether radiation-sensitivity is tied to reported chemical-sensitivity; and whether environmental exposures are apparent risk factors for reported RadAEs (rRadAEs). 81 participants (41 VGWI, 40 controls) rated exposure to, and rRadAEs from, four radiation types. The relations of RadAE-propensity (defined as the ratio of rRadAEs to summed radiation exposures) to Gulf War illness (GWI) presence and severity, and to reported chemical-sensitivity were assessed. Ordinal logistic regression evaluated exposure prediction of RadAE-propensity in the full sample, in VGWI, and stratified by age and chemical-sensitivity. RadAE-propensity was increased in VGWI (vs. controls) and related to GWI severity (p < 0.01) and chemical-sensitivity (p < 0.01). Past carbon monoxide (CO) exposure emerged as a strong, robust predictor of RadAE-propensity on univariable and multivariable analyses (p < 0.001 on multivariable assessment, without and with adjustment for VGWI case status), retaining significance in age-stratified and chemical-sensitivity-stratified replication analyses. Thus, RadAE-propensity, a newly-described GWI-feature, relates to chemical-sensitivity, and is predicted by CO exposure-both features reported for nonionizing radiation sensitivity, consistent with shared mitochondrial/oxidative toxicity across radiation frequencies. Greater RadAE vulnerability fits an emerging picture of heightened drug/chemical susceptibility in VGWI.

Concentration-dependent stimulation of melanin production as well as melanocyte and keratinocyte proliferation by melatonin in human eyelid epidermis

It remains unclear how the multifunctional indoleamine neurohormone, melatonin, alters melanin production and melanocytes within intact human epidermis under physiologically relevant conditions. In the current pilot study, we aimed to clarify this in long-term organ-cultured, full-thickness human eyelid skin, selected for its clinically recognized sensitivity to pigmentation-modulatory hormones. Warthin-Starry histochemistry showed that 100 μM melatonin significantly increased epidermal melanin content and melanocyte dendricity after 6 days of organ culture, even though tyrosinase activity in situ was inhibited, as assessed by quantitative immunohistomorphometry. While the higher melatonin dose tested here (200 μM) did not change epidermal melanization, but again inhibited tyrosinase activity, it increased the number and proliferation of both gp100⁺ epidermal melanocytes and keratinocytes as well as protein expression of the premelanosomal marker, gp100, ex vivo. Contrary to most previous studies, these eyelid skin organ culture results suggest that long-term melatonin application exerts overall stimulatory, dose-dependent effects on the epidermal pigmentary unit within intact human skin, which appear surprisingly tyrosinase-independent. While these provocative preliminary findings require further work-up and independent confirmation, they encourage one to systematically explore whether prolonged melatonin therapy can (re-)stimulate melanogenesis and increase the pool/activity of epidermal melanocytes in hypopigmented skin lesions.

Diplomats' Mystery Illness and Pulsed Radiofrequency/Microwave Radiation

Importance: A mystery illness striking U.S. and Canadian diplomats to Cuba (and now China) "has confounded the FBI, the State Department and US intelligence agencies" (Lederman, Weissenstein, & Lee, 2017). Sonic explanations for the so-called health attacks have long dominated media reports, propelled by peculiar sounds heard and auditory symptoms experienced. Sonic mediation was justly rejected by experts. We assessed whether pulsed radiofrequency/microwave radiation (RF/MW) exposure can accommodate reported facts in diplomats, including unusual ones. Observations: (1) Noises: Many diplomats heard chirping, ringing or grinding noises at night during episodes reportedly triggering health problems. Some reported that noises were localized with laser-like precision or said the sounds seemed to follow them (within the territory in which they were perceived). Pulsed RF/MW engenders just these apparent "sounds" via the Frey effect. Perceived "sounds" differ by head dimensions and pulse characteristics and can be perceived as located behind in or above the head. Ability to hear the "sounds" depends on high-frequency hearing and low ambient noise. (2) Signs/symptoms: Hearing loss and tinnitus are prominent in affected diplomats and in RF/MW-affected individuals. Each of the protean symptoms that diplomats report also affect persons reporting symptoms from RF/MW: sleep problems, headaches, and cognitive problems dominate in both groups. Sensations of pressure or vibration figure in each. Both encompass vision, balance, and speech problems and nosebleeds. Brain injury and brain swelling are reported in both. (3) Mechanisms: Oxidative stress provides a documented mechanism of RF/MW injury compatible with reported signs and symptoms; sequelae of endothelial dysfunction (yielding blood flow compromise), membrane damage, blood-brain barrier disruption, mitochondrial injury, apoptosis, and autoimmune triggering afford downstream mechanisms, of varying persistence, that merit investigation. (4) Of note, microwaving of the U.S. embassy in Moscow is historically documented. Conclusions and relevance: Reported facts appear consistent with pulsed RF/MW as the source of injury in affected diplomats. Nondiplomats citing symptoms from RF/MW, often with an inciting pulsed-RF/MW exposure, report compatible health conditions. Under the RF/MW hypothesis, lessons learned for diplomats and for RF/MW-affected civilians may each aid the other.

Hawthorn Polyphenol Extract Inhibits UVB-Induced Skin Photoaging by Regulating MMP Expression and Type I Procollagen Production in Mice

Ultraviolet (UV) B radiation can cause skin aging by increasing matrix metalloproteinase (MMP) production and collagen degradation, leading to the formation of wrinkles. This study investigated whether hawthorn polyphenol extract (HPE) protects against UVB-induced skin photoaging using HaCaT human keratinocytes, normal human dermal fibroblasts (HDFs), and mice. Analysis of the phenol composition of HPE by high-performance liquid chromatography-mass spectrometry showed that chlorogenic acid (13.5%), procyanidin B2 (19.2%), and epicatechin (18.8%) collectively accounted for 51.4% of total phenol content and represent the active ingredients of hawthorn fruit. A cell viability assay revealed that HPE treatment promoted cell proliferation in HaCaT cells and HDFs. On the other hand, MMP-1 and type I procollagen production was decreased and increased, respectively, in UVB-exposed cells treated with HPE as compared with those without treatment, as determined by enzyme-linked immunosorbent assay. Hematoxylin and eosin and Weigert staining of dermal tissue specimens from mice demonstrated that HPE also reversed UVB-induced epidermal thickening and dermal damage. The increase in production of reactive oxygen species and decrease in antioxidant enzyme activity as well as the increase in nuclear factor-κB activation and mitogen-activated protein kinase phosphorylation induced by UVB irradiation were reversed by HPE (100 or 300 mg/kg body weight), which also suppressed MMP expression and stimulated the production of type I procollagen in the dorsal skin of UVB-irradiated mice. These results suggest that HPE is a natural product that can prevent UVB radiation-induced skin photoaging.

Oxidative stress and antioxidant strategies in dermatology

Oxidative stress results from a prooxidant-antioxidant imbalance, leading to cellular damage. It is mediated by free radicals, such as reactive oxygen species or reactive nitrogen species, that are generated during physiological aerobic metabolism and pathological inflammatory processes. Skin serves as a protective organ that plays an important role in defending both external and internal toxic stimuli and maintaining homeostasis. It is becoming increasingly evident that oxidative stress is involved in numerous skin diseases and that antioxidative strategies can serve as effective and easy methods for improving these conditions. Herein, we review dysregulated antioxidant systems and antioxidative therapeutic strategies in dermatology.

Melatonin alleviates hyperthyroidism induced oxidative stress and neuronal cell death in hippocampus of aged female golden hamster, Mesocricetus auratus

Oxidative stress is a well known phenomenon under hyperthyroid condition that induces various physiological and neural problems with a higher prevalence in females. We, therefore investigated the antioxidant potential of melatonin (Mel) on hyperthyroidism-induced oxidative stress and neuronal cell death in the hippocampus region of brain (cognition and memory centre) of aged female golden hamster, Mesocricetus auratus. Aged female hamsters were randomly divided into four experimental groups (n=7); group-I: control, group-II: Melatonin (5mgkg(-1)day(-1), i.p., for one week), group-III: Hyperthyroid (100μg kg(-1)day(-1), i.p., for two weeks) and group-IV- Hyper+Mel. Hormonal profiles (thyroid and melatonin), activity of antioxidant enzymes (SOD, CAT and GPX), lipid peroxidation level (TBARS) and the specific apoptotic markers (Bax/Bcl-2 ratio and Caspase-3) expression were evaluated. A significant increase in the profile of total thyroid hormone (tT3 and tT4) in hyperthyroidic group as compared to control while tT3 significantly decreased in melatonin treated hyperthyroidic group. However, Mel level significantly decreased in hyperthyroidic group but increased in melatonin treated hyperthyroidic group. Further, the number of immune-positive cells for thyroid hormone receptor-alpha (TR-α) decreased in the hippocampus of hyperthyroidic group and increased in melatonin treated hyperthyroidic group. Profiles of antioxidant enzymes showed a significant decrease in hyperthyroidic group with a simultaneous increase in lipid peroxidation (TBARS). Melatonin treatment to hyperthyroidic group lead to decreased TBARS level with a concomitant increase in antioxidant enzyme activity. Moreover, increased expression of Bax/Bcl-2 ratio and Caspase-3, in hyperthyroidic group had elevated neuronal cell death in hippocampal area and melatonin treatment reduced its expression in hyperthyroidic group. Our findings thus indicate that melatonin reduced the hyperthyroidism-induced oxidative stress and neuronal cell death in the hippocampus region of brain, suggesting a novel therapeutic approach of melatonin for management of cognition and memory function in females under hyperthyroid condition.

Edema, Hyperpigmentation, Induration: 3 Skin Signs Heralding Danger in Patients on Maintenance Hemodialysis

Skin changes are common in patients on dialysis. This study focused on putative associations of specific skin findings with comorbidities and mortality.We performed a retrospective analysis of data from 508 patients on maintenance hemodialysis therapy in 7 centers in the German State of North Rhine Westphalia. Data had been collected by interview, from patient files, and from targeted physical examination in an earlier prospective study screening hemodialysis patients for the presence of nephrogenic systemic fibrosis. While on dialysis, patients' extremities had been examined for any of the following: edematous skin at the lower extremities, hyperpigmentation, induration, and xerosis cutis. Our present data analyses focused on associated mortality and comorbidities.Five hundred eight patients (median age 71 years, range 20.0-95.9; n = 292 men) had agreed to participate in the initial study: 48% (n = 243) were diabetics and 46% (n = 232) had been diagnosed with coronary heart disease. On examination, 86% of patients (n = 439) presented with at least 1 of the prespecified skin changes. Skin edema (n = 89; 18%), hyperpigmentation (n = 74; 15%), and induration (n = 9; 2%) were independently associated with increased mortality over 24 months (P < 0.002, P < 0.030, and P < 0.020, respectively).In our study, prespecified skin changes indicated an increased mortality risk in patients on chronic hemodialysis. Routinely assessing the skin of dialysis patients represents a simple, reliable, and cost effective means of identifying those at greatest risk.