Facial Physiological Characteristics and Skin Microbiomes Changes are Associated with Body Mass Index (BMI).

Background: Overweight and obesity have become public health problems worldwide. An increasing number of research works are focusing on skin physiology and the manifestations of obesity-associated skin diseases, but little is known about the correlations between body mass index (BMI), facial skin physiological parameters, and the facial skin microbiome in healthy women. Objective: To investigate the correlations between BMI, facial skin physiological parameters and facial bacteria and fungi in 198 women aged 18 to 35 years in Shanghai. Methods: According to the international BMI standard and Chinese reference standard, subjects were divided into three groups, "lean" B1, "normal" B2 and "overweight" B3, and the physiological parameters of facial skin were measured by non-invasive instrumental methods, and the skin microbiota was analyzed by 16S rRNA and ITS high-throughput sequencing. Results: Compared with the skin physiological parameters of the normal group, those of the overweight group exhibited a significant increase in trans-epidermal water loss (TEWL), which indicated that the skin barrier was impaired. The skin haemoglobin content was significantly increased, and skin surface pH was significant decreased in those with a high BMI. Furthermore, α-diversity, analysed using the Shannon, Chao, Sobs, and Ace indexes, was increased in the overweight group, suggesting that the diversity and species abundance of facial bacterial and fungal microbiota were also increased. Moreover, the overweight group had higher abundances of Streptococcus, Corynebacterium, Malassezia, and Candida. Notably, skin surface pH was significantly and negatively correlated with the relative abundances of Malassezia, Candida, and Cladosporium. Besides, the abundance of Malassezia was positively associated with the abundances of Staphylococcus and Corynebacterium. Conclusion: These results indicate that BMI is associated with differences in the biophysical properties and microbiome of the facial skin. A high BMI affects the integrity of skin barrier and changes the skin flora diversity and species composition.

Complete genome sequence of Cutibacterium acnes type II CCSM0331, isolated from a healthy woman's skin.

The complete genome sequence of Cutibacterium acnes Type II strain CCSM0331, which was isolated from the healthy facial skin, is reported. The assembled 2.5-Mbp genome comprised a single circular chromosome. These data will provide valuable information on the beneficial role of C. acnes as a skin commensal bacteria.

Aqueous extract of Cordyceps cicadae (Miq.) promotes hyaluronan synthesis in human skin fibroblasts: A potential moisturizing and anti-aging ingredient.

Cordyceps cicadae (Miq.) is an edible fungus with unique and valuable medicinal properties that is commonly used in traditional Chinese medicine, but its anti-aging effects on the skin fibroblast are not well studied. The aim of the present study was to analyze the active components of aqueous C. cicadae extract (CCE), determine the effects of CCE on hyaluronan synthesis in human skin fibroblasts, and explore the underlying mechanisms. The results of this study indicate that CCE was rich in polysaccharides, five alditols (mainly mannitol), eight nucleosides, protein, and polyphenols, which were present at concentrations of 62.7, 110, 8.26, 35.7, and 3.8 mg/g, respectively. The concentration of extract required to inhibit 50% of 2,2-azino-bis (3-ethylbenzothiazo-line-6-sulphonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazil (DPPH) radical scavenging capacities were 0.36 ± 0.03 and 4.54 ± 0.10 mg/mL, respectively, indicating that CCE exhibits excellent antioxidant activities. CCE showed no cytotoxicity to skin fibroblasts at concentrations ≤ 100 µg/mL, and promoted HA synthesis in fibroblasts. Treatment of fibroblast cells with 100 µg/mL CCE enhances the HA content to 1293 ± 142 ng/mL, which is significantly more than that in the non-treatment (NT) group (p = 0.0067). Further, RNA sequencing detected 1,192 differentially expressed genes (DEGs) in CCE-treated fibroblasts, among which 417 were upregulated and 775 were downregulated. Kyoto Encyclopedia of Genes (KEGG) and Genomes pathway (GO) analysis based on RNA sequencing revealed that CCE mainly affected cytokine-cytokine receptor interaction regulated by HA synthesis-related genes. CCE upregulated HA synthase 2 (HAS2), epidermal growth factor (EGF)-related genes, heparin-binding EGF-like growth factor, C-C motif chemokine ligand 2, interleukin 1 receptor-associated kinase 2, and other genes related to fibroblast differentiation and proliferation. CCE downregulated the gene of matrix metallopeptidase 12 (MMP12), which leads to cell matrix loss. RT-qPCR further verified CCE significantly upregulated HAS2 expression and significantly downregulated MMP12 expression, thus promoting hyaluronan synthesis. CCE shows potential as a moisturizer and anti-aging agent in functional foods and cosmetics.

The menstrual cycle regularity and skin: irregular menstrual cycle affects skin physiological properties and skin bacterial microbiome in urban Chinese women.

BACKGROUND: The regularity of the menstrual cycle directly affects women's health. Many studies have focused on menstrual health; however, menstrual cycle regularity-related variations in skin physiological characteristics and skin microbiota have been seldom investigated. METHODS: To investigate the menstrual cycle regularity-related variations in skin physiological characteristics and skin microbiota of 197 cases of Chinese women aged 18-35 years living in shanghai in 2021. Based on a self-evaluation questionnaire, the volunteers were divided into three groups C1 (those with a regular menstrual cycle), C2 (those with a less regular menstrual cycle) and C3 (those with an irregular menstrual cycle). The physiological parameters of facial skin were measured by non-invasive methods and the skin microbiome was analyzed by 16S rRNA high-throughput sequencing. RESULTS: In the C3 group, the hydration content was significantly decreased (p < 0.05), the TEWL was significantly increased (p < 0.05), and the sebum content was increased (p > 0.05), indicating that the skin barrier integrity weakened with increased menstrual cycle irregularity. Additionally, the melanin level, L value and b value were significantly decreased (p < 0.05) in the C3 group, but the a value was significantly increased (p < 0.001), which indicated that the skin color became darker. Furthermore, the skin microbiota diversity decreased with increasing cycle irregularity, but the differences were not significant. The skin microbiota composition showed that the proportion of Firmicutes, Acinetobacter, Staphylococcus and Cutibacterium were increased in those with an irregular menstrual cycle, indicating that alterations in the ratio of bacterial phyla and/or genera might disturb skin homeostasis. Spearman correlation analysis revealed strong correlations between the microbiota and skin physiological parameters. Based on the associations among hormones, skin physiological parameters and skin microbiota, it is possible that the skin physiological parameters, as well as the skin microbial diversity and composition, change with hormonal fluctuations during the menstrual cycle. CONCLUSIONS: An irregular menstrual cycle can affect skin physiological characteristics and the skin microbiota. Female with an irregular menstrual cycle should strengthen skin care practices and use skin care products with moisturising and soothing effects to protect their skin.

Complete Genome Sequence of Staphylococcus capitis CCSM0123, Isolated from Healthy Facial Skin.

Staphylococcus capitis strain CCSM0123 was isolated from healthy facial skin. The complete genome of CCSM0123 was sequenced using a combination of Pacific Biosciences (PacBio) RS II single-molecule real-time (SMRT) and Illumina sequencing. The assembled 2.5-Mbp genome consisted of one chromosome and four plasmids.

Complete Genome Sequence of Staphylococcus epidermidis CCSM0287, Isolated from Healthy Facial Skin.

Staphylococcus epidermidis strain CCSM0287 was isolated from healthy facial skin. The complete genome of CCSM0287 was sequenced using a combination of Pacific Biosciences (PacBio) RS II single-molecule real-time (SMRT) and Illumina sequencing. The assembled 2.5-Mbp genome consisted of one chromosome and three plasmids.

The Characteristics of the Skin Physiological Parameters and Facial Microbiome of "Ideal Skin" in Shanghai Women.

Purpose: Everyone pursues perfect skin, but there exist significant differences between cultures, and no commonly accepted standards have been established. Therefore, our study attempted to define the "ideal skin" of oriental women and analyze the relationship between different skin physiological parameters and microbiomes. Patients and Methods: Based on our customized grading standard, the VISIA CR photos of 111 young women aged from 18 to 25 in Shanghai were collected and scored by the severity of pores, acne, spots, and wrinkles. The volunteers were then divided into "ideal skin" (W1), "normal skin" (W2), and "undesirable skin" (W3) groups. The physiological parameters of facial skin were measured by non-invasive instrumental methods, and the skin microbiome was analyzed by 16S rRNA and ITS high-throughput sequencing. Results: From "ideal skin" to "undesirable skin", the skin physiological parameters, α-diversity, and composition of the facial microbiome showed noticeable regular changes. Compared with the "normal skin" (W2) and "undesirable skin" (W3), the "ideal skin" (W1) group had lower sebum content, TEWL, melanin, hemoglobin, and roughness but higher hydration content and skin pH value. Furthermore, the Shannon index of skin bacteria was significantly increased in W1 (P = 0.004), suggesting that the ideal skin had higher species diversity. From W1 to W3, the species composition was changed significantly. The abundance of Actinobacteria was increased, while Proteobacteria and Bacteroidetes were decreased. Correspondingly, the abundances of lipophilic Propionibacterium and Malassezia were increased, while the abundances of Stenotrophomonas, Pseudomonas, Ralstonia, and Streptococcus, were significantly decreased. Additionally, Spearman correlation analysis revealed strong correlations between the physiological parameters and the microbiota. Notably, the Shannon index of skin bacteria was significantly positively correlated with skin hydration (P = 0.03) but negatively correlated with the abundance of Cutibacterium (P = 0.000), hemoglobin content (P = 0.025), and sebum content (P = 0.5). Therefore, the skin hydration content and the abundance of Cutibacterium played an important role in maintaining the α-diversity and skin homeostasis. Conclusion: Ideal skin had better water-oil balance and barrier function, higher microbial diversity, and more reasonable species distribution. Therefore, daily skincare needs to control skin oil and maintain skin microecological balance to achieve ideal skin conditions for young women aged 18-25 years old.

Regular Late Bedtime Significantly Affects the Skin Physiological Characteristics and Skin Bacterial Microbiome.

Background: Late bedtime is a common form of unhealthy sleep pattern in adulthood, which influences circadian rhythm, and negatively affects health. However, little is known about the effect of regular late bedtime on skin characteristics, particularly on skin microbiome. Objective: To investigate the changes and effects of the regular late bedtime on skin physiological parameters and facial bacterial microbiome of 219 cases of Chinese women aged 18-38 years living in Shanghai. Methods: Based on the Self-Evaluation Questionnaire, bedtime was categorized as 11:00 PM; thus, the volunteers were divided into early bedtime group (S0) and late bedtime group (S1). The physiological parameters of facial skin were measured by non-invasive instrumental methods, and the skin microbiome was analyzed by 16S rRNA high-throughput sequencing. Results: The skin physiological parameters of the late bedtime group exhibited significant decrease in skin hydration content, skin firmness (F4) and elasticity (R2), while TEWL, sebum and wrinkle significantly increased. The result indicated that late bedtime significantly impaired the integrity of skin barrier, damaged skin structure, and disrupted water-oil balance. Furthermore, the analysis of α-diversity, Sobs, Ace and Chao index were found to significantly decrease (P < 0.05) in the late bedtime group, suggesting that late bedtime reduced both the abundance and the diversity of facial bacterial microbiota. Moreover, the abundance of Pseudomonas increased significantly, while Streptococcus, Stenotrophomonas, Acinetobacter, Haemophilus, Actinomyces and Neisseria decreased significantly. In addition, Spearman correlation analysis revealed strong correlations between the microbiota and the physiological parameters. Notably, the abundance of Pseudomonas significantly positively correlated with skin firmness and elasticity, but significantly negatively correlated with skin hemoglobin content, melanin content and skin hydration. Conclusion: Bedtime is an important factor in maintaining skin health. Regular late bedtime not only damages the skin barrier and skin structure but also reduces the diversity and composition of facial bacterial microbiome.

Factor analysis approach unveils the influencing factors of dandruff in the normal teenage population.

The aim of this study was to explore the main factors affecting the occurrence of dandruff in healthy people (nondisease-induced scalp desquamation). This study analyzed the fungal microbial diversity of the scalp in Chinese teenage volunteers and measured scalp sebum secretion, the scalp pH value, and scalp transepidermal water loss. The amount and size of dandruff were measured, and the main factors that influence dandruff in the normal population were identified using principal component analysis. The results showed that an increase in Malassezia restricta led to an increased amount of dandruff in the mild and moderate groups. Conversely, this was not found for individuals in the severe group, whose dandruff symptoms were influenced by scalp barrier function. In terms of dandruff area grouping, the pH value and the amount of sebum secretion were the main factors, with the barrier function and microbial diversity being secondary factors. Dandruff cosmetics should emphasize different treatments for different types of dandruff to achieve better antidandruff effects. The results of this study provide a new theoretical basis for the development of multiple targets for antidandruff agents aimed at the normal population.

Cheek Microbial Communities Vary in Young Children with Atopic Dermatitis in China.

BACKGROUND: Atopic dermatitis (AD) is a chronic, recurrent skin condition with recently increased incidence in younger children. AD development has been correlated with the skin microbiome, and Staphylococcus aureus enrichment causes significant increases in skin lesions. OBJECTIVE: Our objectives were to compare the microbial diversity of the cheek skin of children with or without AD aged 0-1 years in China, and to determine whether 4 types of skin-isolated bacteria could inhibit S. aureus in vitro. METHODS: The skin microbial samples of cheek skin of children were sequenced by 16S rRNA V1-V2 region. Four skin isolated bacterial fermentation supernatants were tested for effects on S. aureus growth, membrane formation, and induction of cytokine secretion from HaCaT cells. RESULTS: Bacterial diversity decreased significantly in skin with severe AD compared to healthy skin (p < 0.01). Seven phyla had content >1%, 4 of which differed in AD (p < 0.05). 38 genera had content >1%, 15 differed (p < 0.05). Differences in 8 species were observed (p < 0.05). In vitro antibacterial and cellular experiments showed that S. aureus growth, biofilm formation, and induction of interleukin (IL)-1α and IL-6 secretion from HaCaT cells were significantly inhibited by Klebsiella oxytoca, Kocuria rhizophila, and Staphylococcus epidermidis culture supernatants (p < 0.05). CONCLUSION: Skin microbiome changes in children varied with age and with AD. There were complex interactions between skin isolated bacteria and S. aureus which could inhibit S. aureus growth and biofilm formation in vitro, suggesting that these microorganisms could be used in AD treatment.

Shifts in the skin microbiome associated with diaper dermatitis and emollient treatment amongst infants and toddlers in China.

BACKGROUND: The microbiological basis of diaper dermatitis has not been clearly elucidated; however, a better understanding of microbial colonization may be vital for developing appropriate therapies. METHODS: Using 16S-rRNA gene sequencing technology, we characterized and compared the bacterial communities obtained from the buttock skin sites of children with diaper dermatitis and from healthy controls. Bacterial diversity in the buttock lesion area and subsequent recovery after emollient treatment have been discussed herein. RESULTS: In buttock skin of children with or without diaper dermatitis, Staphylococcus and Anaerococcus were predominant in the total skin microbiome. Compared with the healthy group, the overall skin bacterial richness and diversity were higher in children with diaper dermatitis, with the abundance of Proteobacteria being significantly higher. In the diaper dermatitis group, the richness of Enterococcus, Erwinia and Pseudomonas was significantly higher, and the levels of Clostridium and Actinomyces were significantly lower than those in healthy children. Richness of Staphylococcus aureus was significantly higher in the diaper dermatitis group, whereas that of Staphylococcus epidermidis and Bifidobacterium longum was lower. Staphylococcus epidermidis and Staphylococcus haemolyticus, the dominant species found in buttock skin, were observed to recover earlier after the disease had improved through emollient treatment. CONCLUSION: Staphylococcus epidermidis, as skin probiotic bacterium, and B longum, Clostridium butyricum and Lactobacillus ruminis, which are intestinal probiotic bacteria, are significantly decreased in diaper dermatitis lesions. These changes in the buttock skin microflora indicate an imbalance in the microflora and suggest that the intestinal microflora may be undergoing dynamic changes. The results of this study suggest that probiotic bacterial supplementation may be useful in the treatment and prevention of diaper dermatitis.

Alterations in the skin microbiome are associated with disease severity and treatment in the perioral zone of the skin of infants with atopic dermatitis.

Atopic dermatitis (AD), a chronic relapsing inflammatory pruritic skin disorder with a unique pathophysiology, has a high incidence in the perioral zone among infants. This study aimed to analyze the association of skin microfloral dynamics with disease severity and treatment of AD in 0-1-year-old infants. Based on the eczema area and severity index, subjects were divided into five groups, i.e., mild, moderate, severe, and severe post-treatment, with a healthy control group, and bacterial density at the perioral lesion, disease severity, and treatment were assessed in 0-1-year-old infants with AD. The perioral lesions were colonized predominantly by Firmicutes, followed in abundance by Proteobacteria, Actinobacteria, and Bacteroidetes. In the phylum Firmicutes, Streptococcus was the most predominant genus. In AD infants, the abundance of Bacteroidetes and Fusobacterium decreased significantly with an increase in disease severity (p < 0.01). The abundance of 6 genera, including Prevotella, decreased significantly with an increase in disease severity (p < 0.05). The abundance of Prevotella melaninogenica decreased gradually with an increase in disease severity and increased after treatment; this trend was reversed for Corynebacterium simulans. A reduction in the abundance of Staphylococcus and an increase in that of skin microflora including Prevotella spp., Staphylococcus epidermidis, and Erwinia dispersa were associated with treatment and clinical improvement. Skin bacterial composition varies with AD severity, and Corynebacterium simulans and Prevotella melaninogenica are positively and negatively correlated with AD severity, respectively. This study provides a theoretical basis to identify potential biomarkers AD occurrence and pathogenesis.

Protective effect of oat bran extracts on human dermal fibroblast injury induced by hydrogen peroxide.

Oat contains different components that possess antioxidant properties; no study to date has addressed the antioxidant effect of the extract of oat bran on the cellular level. Therefore, the present study focuses on the investigation of the protective effect of oat bran extract by enzymatic hydrolysates on human dermal fibroblast injury induced by hydrogen peroxide (H(2)O(2)). Kjeldahl determination, phenol-sulfuric acid method, and high-performance liquid chromatography (HPLC) analysis indicated that the enzymatic products of oat bran contain a protein amount of 71.93%, of which 97.43% are peptides with a molecular range from 438.56 to 1301.01 Da. Assays for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity indicate that oat peptide-rich extract has a direct and concentration-dependent antioxidant activity. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay and the TdT-mediated digoxigenin-dUTP nick-end labeling (TUNEL) assay for apoptosis showed that administration of H(2)O(2) in human dermal fibroblasts caused cell damage and apoptosis. Pre-incubation of human dermal fibroblasts with the Oatp for 24 h markedly inhibited human dermal fibroblast injury induced by H(2)O(2), but application oat peptides with H(2)O(2) at same time did not. Pre-treatment of human dermal fibroblasts with Oatp significantly reversed the H(2)O(2)-induced decrease of superoxide dismutase (SOD) and the inhibition of malondialdehyde (MDA). The results demonstrate that oat peptides possess antioxidant activity and are effective against H(2)O(2)-induced human dermal fibroblast injury by the enhanced activity of SOD and decrease in MDA level. Our results suggest that oat bran will have the potential to be further explored as an antioxidant functional food in the prevention of aging-related skin injury.

Hydrogen peroxide enhanced Ca(2+)-activated BK currents and promoted cell injury in human dermal fibroblasts.

AIMS: Recent studies have shown that dermal fibroblasts possess multiple types of voltage-dependent K(+) channels, and the activation of these channels induces apoptosis. In the present study, we aimed to investigate whether hydrogen peroxide (H(2)O(2)), an oxidative stress inducer, could modulate these channels or induce human dermal fibroblasts injury. MAIN METHODS: The effects of H(2)O(2) on K(+) currents were studied using a whole-cell recording. Intracellular PKC levels were measured with a direct human PKC enzyme immunoassay kit. Cell viability was assessed using PI staining and apoptotic nuclei were detected with TdT-mediated digoxigenin-dUTP nick-end labelling assay (TUNEL) assay. KEY FINDINGS: Treatment of cells with 100µM H(2)O(2) resulted in a partially reversible increase in non-inactivating outward K(+) currents and an alteration in the steady-state activation property of the channels. The H(2)O(2)-induced increase in K(+) currents was mimicked by a PKC activator, and was blocked by the PKC inhibitor or the large conductance Ca(2+)-activited K(+) (BK) channel blockers. The intracellular PKC levels were significantly enhanced by H(2)O(2) treatment in a concentration-dependent manner. After exposure to H(2)O(2), evaluation of fibroblasts survival rate and damaged cell number with TUNEL-positive nuclei revealed an increased cell injury. Blocking the K(+) channels with blockers significantly decreased the H(2)O(2)-induced human dermal fibroblasts injury. SIGNIFICANCE: Our results revealed that H(2)O(2) could enhance BK currents by PKC pathway. Increased K(+) currents might be related to H(2)O(2)-induced human dermal fibroblasts injury. The results reported here contribute to our understanding of the mechanism underlying H(2)O(2)-induced human dermal fibroblasts injury.

Asiaticoside induction for cell-cycle progression, proliferation and collagen synthesis in human dermal fibroblasts.

Asiaticoside, isolated from Centella asiatica, promotes fibroblast proliferation and extracullar matrix synthesis in wound healing. The precise mechanism, however, in molecular and gene expression levels still remains partially understood. Using cDNA microarray technology, the alternation of genes expression profiles was determined in a human dermal fibroblast in vitro in the presence of asiaticoside (30 microg/ml). Fifty-four genes, with known functions for cell proliferation, cell-cycle progression and synthesis of the extracellular matrix, were significantly up-regulated in our "whole-genes nest" expression profile at various timepoints. Furthermore, mRNA levels and protein productions of certain genes responsible for extracellular matrix (ECM) synthesis (e.g. encoding type I and type III collagen proteins) were evaluated by Northern blot and radioimmunoassay, respectively. As a result, there is a close correlation among the gene profile, mRNA and protein production in the cells response to asiaticoside stimulation. This information could be used for exploring the target genes in response to asiaticoside in fibroblasts.

ET-1 inhibits B-16 murine melanoma cell migration by decreasing K(+) currents.

Cell migration is mediated by ion channels and transporters, and plays crucial roles in a variety of physiological and pathological processes. Previously, our studies have shown that a Ca(2+)-regulated K(+) current exists in B-16 murine melanoma cells, and that endothelin-1 (ET-1) inhibits the K(+) current via a PKC-dependent pathway. In the present study, patch-clamp whole-cell recording and transwell migration assays were used to examine the effects of ET-1 on B-16 murine melanoma cell migration. ET-1 (100 nM in the injection pipette and 10 nM in the incubation medium) decreased the K(+) current amplitude by 33.0 +/- 2.5% and inhibited migration of B-16 cells by 57.4 +/- 9.4%. Similarly, the Ca(2+)-regulated K(+) channel blockers, BaCl(2) and quinidine, decreased the K(+) current by 20.5 +/- 1.0% and 36.6 +/- 1.2%, respectively, and slowed migration of B-16 melanoma cells by 37.1 +/- 8.6% and 42.7 +/- 8.8%, respectively. The effect of ET-1 on the K(+) current and cell migration was simulated by ET-3. In contrast, the K(+) channel opener, diclofenac, increased the K(+) current by 128.8 +/- 11.7%, 257.4 +/- 35.8% at concentrations of 1 and 5 mM, respectively. Likewise, the migration of B-16 murine melanoma cells dramatically increased by 75.6 +/- 12.7% in the presence of 100 microM diclofenac in incubation medium. Furthermore, the ET-1- and ET-3-induced inhibition of K(+) current and migration was abrogated by diclofenac. In the presence of diclofenac, ET-1 only reduced the K(+) current amplitude by 10.6 +/- 1.1%, and slowed B-16 cell migration by only 10.8 +/- 8.9%. The results suggest that the K(+) channel-dependent migration of B-16 melanoma cells is modulated by ET-1. Cell Motil.

Ca(2+)-inactivated K+ current is modulated by endothelin-1 in B-16 murine melanoma cells.

It is well established that endothelin-1 (ET-1) plays a role in differentiation and proliferation in a variety of cells such as fibroblasts and human melanoma cells via a receptor-mediated mechanism. However, whether ET-1 modulates ion channel activity in these cell types is still unknown. In this report, we recorded the voltage-dependent outward K+ current in cultured B16 melanoma cells using the patch-clamp technique. Biophysical and pharmacological properties of the K+ current, and the effect of ET-1 on the K+ current were investigated. When cells were loaded with a Ca(2+)-chelating agent (EGTA or BAPTA), the K+ current amplitude gradually increased with time after establishment of the whole cell configuration. Replacement of Ca2+ with Co2+ in the extracellular medium caused no significant modulation of the K+ current amplitude. Addition of BaCl2 or quinidine to the extracellular solution reduced the K+ current amplitude, whereas the K+ current was insensitive to tetraethylammonium. ET-1 (10 nM) reversibly decreased the K+ current amplitude and accelerated the decay of the K+ current. The ET-1-induced inhibitory effect displayed no desensitization following repeated ET-1 application. Pretreatment with pertussis toxin (PTX) or perfusion of cells with the protein kinase C (PKC) inhibitor H-7 abolished the inhibitory effect of ET-1 on the K+ current. We conclude that the outward K+ current recorded in murine B-16 melanoma cells represents a Ca(2+)-inactivated K+ current, and that the inhibitory effect of ET-1 on the K+ current may reveal a novel mechanism to control the differentiation and proliferation of melanoma cells.

[Study on mitochondrial DNA damage in peripheral blood nucleate cells of the workers exposed to acrylonitrile].

OBJECTIVE: To study the potential aging effect on workers exposed to acrylonitrile (ACN). METHODS: The deletion rates of mitochondrial DNA (mtDNA) in peripheral blood nucleate cells of 47 exposed workers and 47 non-exposed workers (as control), as well as 12 old people and 12 young people were measured with polymerase chain reaction (PCR). RESULTS: The positive rates of mtDNA deletion in peripheral blood nucleate cells were 17.02% in the workers exposed to ACN and 25.00% in group of old people. However, the mtDNA deletion was not detected in the control group and young people. CONCLUSIONS: ACN could induce mtDNA deletion in peripheral blood nucleate cells of the exposed workers. There may be a potential molecular effect of occupational ACN exposure on workers' aging.