First principles study of strain effects on prospective 2D photocatalysts Sn2Se2X4 (X = P, As) with ultra-high charge carrier mobility.

Ab initio calculations were employed to investigate the properties of Sn2Se2P4 and Sn2Se2As4, which are new semiconductors formed based on the 2D SnP3 structure. A comprehensive analysis was conducted to examine the structural characteristics and stability of both compounds. It was observed that both Sn2Se2P4 and Sn2Se2As4 exhibit notable toughness and ductility, characterized by a Poisson's ratio ranging from 0.16 to 0.20 and a Young's modulus ranging from 42.12 to 49.84 N m-1. The investigation focused on the examination of the electronic characteristics of the two compounds, as well as their correlation with optical properties, charge transport, and potential as photocatalysts. Being ductile semiconductors, the effects of strains on the properties of Sn2Se2P4 and Sn2Se2As4 were also investigated. The charge carrier mobility in the y-direction ranges from 103 to 104 cm2 V-1 s-1. Moreover, the electron-hole separation is expected to be very high as the difference in the mobilities of holes and electrons is really large. Moreover, it is worth noting that both Sn2Se2P4 and Sn2Se2As4 exhibit a significantly high absorption rate of 106 cm-1 in the visible region. The observed features of Sn2Se2P4 and Sn2Se2As4 indicate their potential as effective photocatalysts for the process of water splitting through the utilization of solar energy.

Modifications of surgical techniques in laparoscopic percutaneous extraperitoneal closure of inguinal ring for childhood inguinal hernia to achieve zero recurrence and zero subcutaneous stitch granuloma.

PURPOSE: To present our technical modifications of single incision laparoscopic percutaneous extraperitoneal closure (SILPEC) of the internal inguinal ring (IIR) for pediatric inguinal hernia (PIH). METHODS: The prospectively collected data of all children diagnosed with PIH undergoing SILPEC at our center from 2016 to 2023 were reviewed and divided into two groups for result comparison: Group A: before and Group B: after the implementation of full modifications. Our modifications included using a nonabsorbable monofilament suture, creating a peritoneal thermal injury at the internal inguinal ring (IIR), employing a cannula to ensure the suture at the IIR ligates only the peritoneum, and double ligation of the IIR in selected cases. RESULTS: 1755 patients in group A and in group B (1 month to 14 years old) were enrolled. There were no significant differences regarding baseline patient characteristics between the two groups. At a median follow-up of 40 months, the rate of recurrent CIH and subcutaneous stitch granuloma (SSG) was 2.3% and 1.5% in group A vs. 0% and 0% in group B (p < 0.001). There were no hydroceles, no ascended or atrophic testis. CONCLUSIONS: Our SILPEC technical modifications can achieve zero recurrence and zero SSG for PIH.

Prognostic Value of Acute Gastrointestinal Injury Combined with Disease Severity Scores in Critically Ill Patients.

Background: Critically ill patients are at high risk of multiple organ failure syndrome (MODS) and gastrointestinal (GI) injury and dysfunction, which are associated with increased mortality rates. The acute gastrointestinal injury (AGI) scale has shown promise in assessing GI dysfunction. However, the combined utility of AGI with established disease severity scores remains unclear. This study aimed to investigate the performance of AGI in conjunction with modified nutritional risk in critically ill (mNUTRIC), sequential organ failure assessment (SOFA), and acute physiology and chronic health evaluation II (APACHE II) scores for predicting mortality in critically ill patients. Materials and methods: A retrospective cross-sectional study was conducted in the intensive care unit (ICU) from May 2021 to December 2021. Demographic and clinical data were collected, including AGI grade, mNUTRIC score, SOFA score, APACHE II score, and mortality. Results: Among 93 critically ill patients, AGI was observed in 47.3% of cases, and the in-hospital mortality rate was 30.1%. The area under the curve (AUC) for AGI in predicting in-hospital mortality was 0.67 [95% confidence interval (CI), 0.56, 0.79; p = 0.008], similar to the AUCs of SOFA, APACHE II, and mNUTRIC scores. The combination of AGI with mNUTRIC, APACHE II, or SOFA scores improved the predictive performance compared with AGI alone. Conclusion: The AGI grade, in conjunction with disease severity scores, such as mNUTRIC, SOFA, and APACHE II scores, shows promise in predicting mortality in critically ill patients. Integrating AGI into evaluating critically ill patients can enhance prognostic accuracy. How to cite this article: Hai PD, Tot NH, Thao LT, Khoa Q, Thien DH. Prognostic Value of Acute Gastrointestinal Injury Combined with Disease Severity Scores in Critically Ill Patients. Indian J Crit Care Med 2024;28(6):575-580.

Complete genome sequence of a novel lytic phage of Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen in rice.

Bacteriophage L522, which infects Xanthomonas oryzae pv. oryzae, was isolated from a paddy leaf sample collected in Long An province, Vietnam. The phage shows myovirus morphology based on transmission electron microscopy. It displays a latent period and burst size of approximately 3 h and 63 new virions per infected cell (PFU/infected cell), respectively. The genome of L522 is 44,497 bp in length, with 52% GC content. Of the 63 genes identified, functions were predicted for 26. No virulence or antibiotic-resistance genes were detected. The results of a BLASTn search showed similarity to a previously reported Xanthomonas phage, with 85% average nucleotide sequence identity and 87.15% query coverage. Thus, this L522 is a representative of a new species in the genus Xipdecavirus.

COVID-19 vaccination: public preference and intention in Vietnam.

Backgrounds: Understanding public opinion in relation to vaccination is critical, as there are several COVID-19 vaccines approved for use in Vietnam. This study aimed to assess public COVID-19 vaccine preferences and intention in Can Tho, Vietnam. Methods: An analytical cross-sectional study was performed between September 20 and October 20, 2021. in people aged 18 and over living in Can Tho, Vietnam, A questionnaire captured demographic information, vaccination intention, preference for vaccine selection, and barriers and motivations related to COVID-19 vaccination. Predictors for vaccination willingness among unvaccinated people were determined using multivariable logistic regression. Results: Out of the proposed vaccines that have been approved by the Vietnam Ministry of Health, AstraZeneca (31.4%), Pfizer (23.5%), and Moderna (14.7%) were the most preferred by participants. Out of 1,470 respondents, 35.8% have received at least one vaccine dose, and of these, 76.9% intended to continue to receive vaccinations. Among the unvaccinated, 74.8% reported that they would be willing to complete the vaccination. Most participants stated that they would receive a COVID-19 vaccine if provided with adequate information on effectiveness and safety (92.7%). The possibility of side effects after vaccination (75.4%) was the most important barrier to vaccination. Education, health status, and prior flu-vaccination were associated with the intention to receive a COVID-19 vaccination among those who had not previously received one. Conclusions: Many unvaccinated adults were willing to receive a COVID-19 vaccination, with AstraZeneca being the preferred choice. These findings could help in the planning of vaccination campaigns to increase vaccination uptake in Vietnam.

Baseline Quality-of-Life of Caregivers of Patients With Heart Failure Prior to Advanced Therapies: Findings From the Sustaining Quality of Life of the Aged: Transplant or Mechanical Support (SUSTAIN-IT) Study.

BACKGROUND: We compared health-related quality of life (HRQOL), depressive symptoms, anxiety, and burden in caregivers of older patients with heart failure based on the intended therapy goal of the patient: awaiting heart transplantation (HT) with or without mechanical circulatory support (MCS) or prior to long-term MCS; and we identified factors associated with HRQOL. METHODS: Caregivers (n = 281) recruited from 13 HT and MCS programs in the United States completed measures of HRQOL (EQ-5D-3L), depressive symptoms (PHQ-8), anxiety (STAI-state), and burden (Oberst Caregiving Burden Scale). Analyses included ANOVA, Kruskal-Wallis tests, χ2 tests, and linear regression. RESULTS: The majority of caregivers were female, white spouses with ≤ 2 comorbidities, median [Q1,Q3] age = 62 [57.8, 67.0] years. Caregivers (HT with MCS = 87, HT without MCS = 98, long-term MCS = 96) reported similarly high baseline HRQOL (EQ-5D-3L visual analog scale median score = 90; P = 0.67 for all groups) and low levels of depressive symptoms. STAI-state median scores were higher in the long-term MCS group vs the HT groups with and without MCS, (38 vs 32 vs 31; P < 0.001), respectively. Burden (task: time spent/difficulty) differed significantly among groups. Caregiver factors (number of comorbidities, diabetes and higher anxiety levels) were significantly associated with worse caregiver HRQOL, R2 = 26%. CONCLUSIONS: Recognizing caregiver-specific factors, including comorbidities and anxiety, associated with the HRQOL of caregivers of these older patients with advanced HF may guide support strategies.

Perspectives on COVID-19 prevention and treatment using herbal medicine in Vietnam: A cross-sectional study.

Introduction: The significance of herbal medicine (HM) during the COVID-19 pandemic has been confirmed. Nevertheless, limited studies have included the people perspectives on COVID-19 prevention/treatment using herbal medicine in Vietnam. Thus, this study tackled the aforementioned issue. Methods: Online-based cross-sectional study was conducted in Vietnamese adults between February-April 2021. Descriptive analysis, regression and Chi-squared tests were implemented for the statistical purposes. Results: total of 787 respondents attended the study, 368 (46.8%) confirmed that they use herbal medicine/nutritional supplements for COVID-19 prevention/treatment. Over 50% of the respondents possessed positive perspective on vitamin C ingestion. Using herbal medicine for external use as a disinfectant was mostly preferred. Respondents who had a 'very good' health self-perception or who lived in rural areas, were more likely to have a positive opinion in the COVID-19 prevention/treatment using herbal medicine. The main barrier for herbal medicine utilization was the deficiency of personal experience or expert advice. Conclusion: The Vietnamese people commonly utilize herbal medicine for the COVID-19 prevention/treatment. These data might help policy-makers in managing the public knowledge and practice on herbal medicine use in Vietnam.

Household-Contact Investigation for Detection of Tuberculosis in Vietnam.

BACKGROUND: Active case finding is a top priority for the global control of tuberculosis, but robust evidence for its effectiveness in high-prevalence settings is lacking. We sought to evaluate the effectiveness of household-contact investigation, as compared with standard, passive measures alone, in Vietnam. METHODS: We performed a cluster-randomized, controlled trial at clinics in 70 districts (local government areas with an average population of approximately 500,000 in urban areas and 100,000 in rural areas) in eight provinces of Vietnam. Health workers at each district clinic or hospital were assigned to perform either household-contact intervention plus standard passive case finding (intervention group) or passive case finding alone (control group). In the intervention districts, household contacts of patients with positive results for tuberculosis on sputum smear microscopy (smear-positive tuberculosis) were invited for clinical assessment and chest radiography at baseline and at 6, 12, and 24 months. The primary outcome was the cumulative incidence of registered cases of tuberculosis among household contacts of patients with tuberculosis during a 2-year period. RESULTS: In 70 selected districts, we enrolled 25,707 household contacts of 10,964 patients who had smear-positive pulmonary tuberculosis. In the 36 districts that were included in the intervention group, 180 of 10,069 contacts were registered as having tuberculosis (1788 cases per 100,000 population), as compared with 110 of 15,638 contacts (703 per 100,000) in the control group (relative risk of the primary outcome in the intervention group, 2.5; 95% confidence interval [CI], 2.0 to 3.2; P<0.001); the relative risk of smear-positive disease among household contacts in the intervention group was 6.4 (95% CI, 4.5 to 9.0; P<0.001). CONCLUSIONS: Household-contact investigation plus standard passive case finding was more effective than standard passive case finding alone for the detection of tuberculosis in a high-prevalence setting at 2 years. (Funded by the Australian National Health and Medical Research Council; ACT2 Australian New Zealand Clinical Trials Registry number, ACTRN12610000600044 .).

Dynamic Alteration of Neutrophil-to-Lymphocyte Ratio over Treatment Trajectory is Associated with Survival in Esophageal Adenocarcinoma.

BACKGROUND: Neutrophil-to-lymphocyte ratio (NLR) has been identified as a biomarker for multiple malignancies. There is emerging evidence that implicates neutrophils in cancer progression. Alterations of neutrophil counts and NLR during treatment may reflect a change in oncologic outcome that is more important than baseline values. The aim of this study is to investigate the prognostic role of NLR changes during the treatment trajectory of patients with esophageal adenocarcinoma. PATIENTS AND METHODS: NLR values of patients with esophageal adenocarcinoma who underwent surgery between 2005 and 2016 were measured at baseline and in the late postoperative period. Primary outcomes were overall survival (OS) and disease-free survival (DFS). The secondary outcome was pathological response to neoadjuvant chemotherapy. RESULTS: 330 patients were included; mean age was 65.6 years, and 82% were male. Most patients had cT3 (74.8%), cN-positive (59.7%) disease. Two-thirds (65.2%) received neoadjuvant chemotherapy. The independent predictors of OS were pathological N-stage, size of primary tumor, and delta NLR (late - baseline NLR). Patients with persistently elevated NLR did worse than those with decreasing NLR trends between baseline and postoperative time points (3-year OS 43.4% versus 71.3%, p < 0.0001, 3-year DFS 29.7% versus 61.9%, p < 0.0001). High baseline and postoperative NLR were associated with significantly worse OS and DFS. Patients with complete pathological response had lower mean baseline NLR. CONCLUSION: Dynamic changes in NLR during treatment are associated with survival and may be more informative than static baseline values.

Post-treatment Mortality Among Patients With Tuberculosis: A Prospective Cohort Study of 10 964 Patients in Vietnam.

BACKGROUND: Tuberculosis is the leading infectious cause of death. Steep reductions in tuberculosis-related mortality are required to realize the World Health Organization's "End Tuberculosis Strategy." However, accurate mortality estimates are lacking in many countries, particularly following discharge from care. This study aimed to establish the mortality rate among patients with pulmonary tuberculosis in Vietnam and to quantify the excess mortality in this population. METHODS: We conducted a prospective cohort study among adult patients treated for smear-positive pulmonary tuberculosis in 70 clinics across Vietnam. People living in the same households were recruited as controls. Participants were re-interviewed and their survival was established at least 2 years after their treatment with an 8-month standardized regimen. The presence of relapse was established by linking identifying data on patients and controls to clinic registries. Verbal autopsies were performed. The cumulative mortality among patients was compared to that among a control population, adjusting for age and gender. RESULTS: We enrolled 10964 patients and 25707 household controls. Among enrolled tuberculosis patients, 9% of patients died within a median follow-up period of 2.9 years: 342 (3.1%) during treatment and 637 (5.8%) after discharge. The standardized mortality ratio was 4.0 (95% confidence interval 3.7-4.2) among patients with tuberculosis, compared to the control population. Tuberculosis was the likely cause of death for 44.7% of these deceased patients. CONCLUSIONS: Patients treated for tuberculosis had a markedly elevated risk of death, particularly in the post-treatment period. Interventions to reduce tuberculosis mortality must enhance the early detection of drug-resistance, improve treatment effectiveness, and address non-communicable diseases.

Genetic relationships among Vietnamese local pigs investigated using genome-wide SNP markers.

Vietnam is one of the most important countries for pig domestication, and a total of 26 local breeds have been reported. In the present study, genetic relationships among the various pig breeds were investigated using 90 samples collected from local pigs (15 breeds) in 15 distantly separated, distinct areas of the country and six samples from Landrace pigs in Hanoi as an out-group of a common Western breed. All samples were genotyped using the Illumina Porcine SNP60 v2 Genotyping BeadChip. We used 15 160-15 217 SNPs that showed a high degree of polymorphism in the Vietnamese breeds for identifying genetic relationships among the Vietnamese breeds. Principal components analysis showed that most pigs indigenous to Vietnam formed clusters correlated with their original geographic locations. Some Vietnamese breeds formed a cluster that was genetically related to the Western breed Landrace, suggesting the possibility of crossbreeding. These findings will be useful for the conservation and management of Vietnamese local pig breeds.

Development of a method for direct extraction of viral RNA from bivalve molluscs.

The detection of foodborne viruses in bivalve molluscs is a challenging procedure in relation to low virus concentration and to the presence of significant RT-PCR inhibitors. The aim of this study was the development of an efficient direct extraction method for foodborne viral RNA from bivalve molluscs. Using Mengovirus as a surrogate for foodborne viruses, five extraction methods based on RNA release by Trizol were compared on clams and oysters. A procedure consisting of Trizol, PureLink RNA Mini Kit, followed by Cetyltrimethylammonium bromide (CTAB) treatment and LiCl precipitation was found to provide RNA with the highest extraction efficiency and negligible inhibitory effect on real-time RT-PCR. This procedure was further compared to standard extraction method (ISO 15216) using clam, mussel and oyster samples spiked with Hepatitis A virus, Norovirus (NoV) GI and GII as well as bivalve samples naturally contaminated with NoV GI or GII. Results clearly demonstrated that the developed method provided, on average, a recovery 4·3 times higher than the standard reference protocol as well as good repeatability. SIGNIFICANCE AND IMPACT OF THE STUDY: A direct extraction procedure was developed to recover viral RNA from shellfish with improved efficiency in comparison to reference extraction method (ISO 15216). Without the need for specific equipment, this procedure offers an alternative for performing food safety controls and for risk assessment studies. Given the inclusion in this extraction method of several steps for the efficient removal of food components inhibiting PCR reaction, this approach could serve as a general scheme for the extraction of nucleic acids of other enteric viruses and/or from other food categories.

Crocin, a natural molecule with potentially beneficial effects against skin ageing.

OBJECTIVE: Oxidative stress and low-grade chronic inflammation stand out as key features of physiological skin ageing. The aim of this study was to examine in normal human epidermal keratinocytes (NHEK) and human dermal fibroblasts (HDF) grown in vitro, the antioxidant and anti-inflammatory properties of crocin, a carotenoid glycoside responsible for the colour of saffron. Moreover, considering the newly emerging field of skin glycobiology and the presence of two gentiobiosyl moieties in crocin, the effect of crocin on NHEK glycosylation pathways was for the first time investigated. METHODS: The anti-inflammatory and antioxidant activities of crocin were evaluated by in vitro assays of antioxidation activities, ELISA and microarray analysis. The effect of crocin on keratinocyte glycobiology was evaluated by proprietary GLYcoDiag lectin technologies and microarray analysis. RESULTS: Crocin is endowed with antioxidant potential against reactive oxygen species, protects squalene against UVA-induced peroxidation and prevents the release of inflammatory mediators. The expression of NF-kB-related genes and glycosylation-related genes is modulated in the presence of crocin. CONCLUSION: Results could designate this molecule as a promising skin ageing prevention cosmetic agent. Of note, some of these effects could be mediated by protein O-glycosylation and interaction of crocin with osidic receptors of keratinocytes.

Oncogenic role of PDK4 in human colon cancer cells.

BACKGROUND: Cancer cells maintain high rates of glycolysis. Pyruvate dehydrogenase kinases (PDK) contribute to this phenomenon, which favours apoptosis resistance and cellular transformation. We previously reported upregulation of PDK4 in normal mucosa of colorectal cancer (CRC) patients compared with controls and in preneoplastic intestine of our mouse model. Decreased methylation of four consecutive PDK4 CpGs was observed in normal mucosa of patients. Although other members of the PDK family have been investigated for transformation potential, PDK4 has not been extensively studied. METHODS: PDK4 methylation in blood of CRC patients and controls was evaluated by pyrosequencing. PDK4 expression in human colon carcinoma cells was down-regulated by RNAi. Cellular migration and invasion, apoptosis and qRT-PCR of key genes were assessed. RESULTS: Pyrosequencing revealed decreased methylation of the same four consecutive CpGs in the blood of patients compared with controls. Cellular migration and invasion were reduced and apoptosis was increased following transient or stable inhibition of PDK4. Expression of vimentin, HIF-1 and VEGFA was reduced. CONCLUSIONS: These studies demonstrate the involvement of PDK4 in transformation. Methylation assessment of PDK4 in the blood may be useful for non-invasive CRC detection. PDK4 should be considered as a target for development of anticancer strategies and therapies.

Neutrophil autophagy and extracellular DNA traps contribute to airway inflammation in severe asthma.

BACKGROUND: Autophagy and neutrophil extracellular DNA traps (NETs) are implicated in asthma; however, their roles in asthma pathogenesis have not been elucidated. OBJECTIVES: We compared autophagy and NET production levels from peripheral blood neutrophils (PBNs) of patients with severe asthma (SA) and non-severe asthma (NSA). Additionally, we investigated the inflammatory effects of NETs on human airway epithelial cells (AECs) and peripheral blood eosinophils (PBEs). METHODS: Peripheral blood neutrophils from patients with SA (n = 30) and NSA (n = 38) were treated with interleukin (IL)-8 (100 ng/mL). Autophagy (light chain 3-II expression) and NET production levels were evaluated by Western blot, immunofluorescence microscopy, and PicoGreen assay. The effects of NETs on AECs were assessed by investigating cell death, cell detachment, expression of occludin and claudin-1, and IL-8 production; the effects of NETs on PBEs were examined by investigating the activation and release of eosinophil cationic protein (ECP) and eosinophil-derived neurotoxin (EDN). RESULTS: Untreated and IL-8-treated PBNs from the SA group produced higher autophagy and NET levels compared with those from the NSA group (P < 0.01). IL-8 increased autophagy and NET levels in PBNs from the SA group, but not from the NSA group. NET levels were correlated with autophagy levels in PBNs (P < 0.001). IL-8-induced NET production levels negatively were correlated with FEV1/FVC (r = -0.700, P = 0.016). NETs induced cell death, detachment, degradation of occludin and claudin-1, and IL-8 production from AECs. Higher levels of NET-induced ECP and EDN were released from PBEs in SA compared with NSA groups. CONCLUSIONS AND CLINICAL RELEVANCE: Neutrophil autophagy and NETs could enhance asthma severity by damaging airway epithelium and triggering inflammatory responses of AECs and PBEs. Modulating neutrophil autophagy and NET production may be a new target therapy for SA.

Autophagy mechanisms in sputum and peripheral blood cells of patients with severe asthma: a new therapeutic target.

BACKGROUND: Autophagy and genetic predisposition have been suggested to potentially play roles in the development of asthma. However, little is known about the role of autophagy in the pathogenesis of severe asthma. OBJECTIVE: We compared autophagy in the sputum granulocytes, peripheral blood cells (PBCs) and peripheral blood eosinophils (PBEs) between patients with severe asthma and those with non-severe asthma and investigated the functional effects of autophagy. METHODS: We enrolled 36 patients with severe asthma, 14 with non-severe asthma and 23 normal healthy controls in this study. Sputum granulocytes, PBCs and PBEs were isolated from each subject. Autophagy was evaluated based on the expression of microtubule-associated protein light chain 3 (LC3) by Western blot, confocal microscopy, transmission electron microscopy and flow cytometry. IL-8 levels were measured by ELISA. To induce autophagy, HL-60 cells, human primary small airway epithelial cells (SAECs) and A549 cells were treated with IL-5, IL-1ß and TNF-α. To inhibit autophagy, PI3K inhibitors (LY29400 and 3-methyladenine [3-MA]) and hydroxychloroquine (HCQ) were used. Knockdown of ATG5 and Beclin-1 was performed in A549 cells, and the therapeutic effects of dexamethasone were evaluated. RESULTS: Higher autophagy levels were noted in sputum granulocytes, PBCs and PBEs from patients with severe asthma than from patients with non-severe asthma and healthy controls (P < 0.05 for all). IL-5 increased autophagy levels in both PBCs and PBEs (P < 0.05). 3-MA attenuated the increased expression of LC3-II and eosinophil cationic protein in HL-60 cells induced by IL-5 (P = 0.034 for both). Dexamethasone did not affect autophagy levels in PBEs. IL-1ß increased LC3-II expression and IL-8 production (P < 0.01) in SAECs, and this was attenuated by LY294002, 3-MA, HCQ and knockdown of ATG5 and Beclin-1 (in A549 cells) (P < 0.01). CONCLUSIONS AND CLINICAL RELEVANCE: Autophagy could play a role in the pathogenesis of severe asthma. Autophagy modulation may be a novel therapeutic target for conventional therapy-resistant severe asthma.

Consequences of urban pollution upon skin status. A controlled study in Shanghai area.

OBJECTIVE: After preliminary studies aimed at measuring pertinent biochemical parameters, potentially modified in subjects exposed to bad environmental conditions, a dedicated study was performed in Shanghai city to evaluate the effect of Urban pollution upon human skin and to collect feedback from the volunteers under study. METHODS: This study was performed during summer 2008 in two different districts of Shanghai, on 159 local residents: 79 subjects from Xu Jia Hui (a centre Shanghainese area), more exposed to pollution, and 80 subjects from Chong Ming, an agricultural region closely located north of Shanghai (<100 kms) and less exposed to pollution, according to official data. Biochemical parameters were measured on skin, and feedback from volunteers was collected through a graduated 'Likert scale' questionnaire under a point scale (strongly agree, agree, disagree, strongly disagree and none). RESULTS: The study demonstrated significant differences in several biochemical parameters measured in Chong Ming area, as compared to Urban area, with an increased ratio of squalene/lipids, a lower level of lactic acid and a better cohesion of stratum corneum. Both sebum excretion rate and sebum casual levels did not differ between the two districts. The volunteer's feedback evidenced a perceived link between pollution and their skin problems. CONCLUSION: This study demonstrated a significant impact of the pollution upon the skin status, as illustrated by changes in superficial biochemical parameters and volunteers' perception.

Oxidization of squalene, a human skin lipid: a new and reliable marker of environmental pollution studies.

A review of the oxidization of squalene, a specific human compound produced by the sebaceous gland, is proposed. Such chemical transformation induces important consequences at various levels. Squalene by-products, mostly under peroxidized forms, lead to comedogenesis, contribute to the development of inflammatory acne and possibly modify the skin relief (wrinkling). Experimental conditions of oxidation and/or photo-oxidation mechanisms are exposed, suggesting that they could possibly be bio-markers of atmospheric pollution upon skin. Ozone, long UVA rays, cigarette smoke… are shown powerful oxidizing agents of squalene. Some in vitro, ex vivo and in vivo testings are proposed as examples, aiming at studying ingredients or products capable of boosting or counteracting such chemical changes that, globally, bring adverse effects to various cutaneous compartments.

Evaluation of the impact of urban pollution on the quality of skin: a multicentre study in Mexico.

OBJECTIVE: After pilot and preliminary studies aimed at identifying pertinent biochemical parameters, a multicenter clinical study was performed to evaluate the effect of pollution on human skin. METHODS: The clinical study was performed in collaboration with the 'Centre Régional de lutte contre le cancer de Montpellier' and the 'National Institute of Public Health of Mexico' on 96 subjects in Mexico City (exposed to pollution) and 93 subjects in Cuernavaca (less exposed to pollution). Both biochemical and clinical skin parameters were studied. RESULTS: The study demonstrated significant quantitative and qualitative modifications of parameters related to sebum excretion in Mexico City compared to Cuernavaca one: An increased level of sebum excretion rate, a lower level of vitamin E and squalene in sebum, an increase of lactic acid and a higher erythematous index on the face of the subjects. In the stratum corneum, a significant higher level of carbonylated proteins and a lower level of IL 1α were noticed, as well as a decrease of ATP concentration with a decrease of chymotrysin like activity, without modifications of corneodesmosin content and trypsin like activity. From a clinical point of view, a higher frequency of atopic and urticarial skins, a higher frequency of red dermographism, an important seborrheic status at the forehead level and a lower level of dandruffs were noted in Mexico City population. The analysis taking into account the sex does not modify the observed results. CONCLUSION: The study demonstrated an important impact of polluted environmental conditions on skin quality, evidencing important modifications of superficial biochemical parameters. The cause/effects relationships of these modifications remain, however, to be further assessed by a complementary in vitro/in vivo approaches.