101 research outputs found
Development of an efficient extraction methodology to analyse potential inflammatory biomarkers from sebum
No full textIntroduction: proteins, such as cytokines and chemokines, are present in varying concentrations in a range of biofluids, with an important signalling role in maintaining homeostasis. Commercial tapes have been employed to non-invasively collect these potential biomarkers in sebum from the skin surface to examine their concentrations in conditions including acne, atopic dermatitis and pressure ulcers. However, the identification of robust biomarker candidates is limited by the low abundance of specific proteins extracted by current methodologies. Therefore, this study was designed to develop an optimized extraction method for potential inflammatory biomarkers in sebum collected with Sebutapes. Methods: commercial tapes (Sebutapes) coated with synthetic sebum were used to systematically evaluate the effects of chemical and mechanical stimuli on extraction efficiency. Varying concentrations of high and low abundance biomarkers (IL-1α, IL-6, Il-8, INF-γ, TNF-α and IL-1RA) were used to spike the synthetic sebum samples. Methodological variables included different surfactants, mechanical stimuli and buffer volume. Extraction efficiency was estimated using immunoassay kits from the extracted buffer. Results: the results revealed that the use of a surfactant, i.e. β-dodecyl maltoside in addition to the mechanical stimuli, namely sonication and centrifugation resulted in an increased recovery of cytokines, ranging from 80% for high-abundant cytokines, such as IL-1α and IL-1RA, and up to 50% for low-abundance cytokines, including TNF-alpha, IL-6 and IL-8. Compared to previous methods, the new extraction protocol resulted in between an 1.5 - 2.0 fold increase in extraction efficiency. Conclusion: the study revealed that there was a high degree of variability in the extraction efficiency of different cytokines. However, improved efficiency was achieved across all cytokines with selective surfactants and mechanical stimuli. The optimised protocol will provide means to detect low levels of potential biomarkers from skin surface, enabling the evaluation of local changes in pro- and anti-inflammatory cytokines present in different skin conditions
Inflammatory biomarkers in sebum for identifying skin damage in patients with a stage I pressure ulcer in the pelvic region: a single centre observational, longitudinal cohort study with elderly patients
No full textPressure Ulcers (PU) are a major burden for affected patients and healthcare providers. Current detection methods involve visual assessments of the skin by healthcare professionals. This has been shown to be subjective and unreliable, with challenges associated with identifying erythema in darker colour skin. Although there exists a number of promising non-invasive biophysical techniques such as ultrasound, capacitance measurements, and thermography, the present study focuses on directly measuring the changes in the inflammatory status of the skin and underlying tissues. Therefore, in this study, we aim to analyse inflammatory cytokines collected through non-invasive sampling techniques to detect early signs of skin damage. Thirty hospitalised patients presenting with Stage I PU were recruited to evaluate the inflammatory response of skin at the site of damage and an adjacent healthy control site. Sebutapes were collected over three sessions to investigate the temporal changes in the inflammatory response. The panel of cytokines investigated included high-abundance cytokines, namely, IL-1α and IL-1RA, and low abundance cytokines; IL-6, IL-8, TNF-α, INF-γ, IL-33, IL-1β and G-CSF. Spatial and temporal differences between sites were assessed and thresholds were used to determine the sensitivity and specificity of each biomarker. The results suggest significant (P < .05) spatial changes in the inflammatory response, with upregulation of IL-1α, IL-8, and G-CSF as well as down-regulation of IL-1RA over the Stage I PU compared with the adjacent control site. There were no significant temporal differences between the three sessions. Selected cytokines, namely, IL-1α, IL-1RA, IL-8, G-CSF, and the ratio IL-1α/IL-1RA offered clear delineation in the classification of healthy and Stage-I PU skin sites, with receiver operating characteristic curves demonstrating high sensitivity and specificity. There were limited influences of intrinsic and extrinsic factors on the biomarker response. Inflammatory markers provided a high level of discrimination between the sites presenting with Stage I PU and an adjacent healthy skin site, in a cohort of elderly inpatients. Indeed, the ratio of IL-1α to IL-1RA provided the highest sensitivity and specificity, indicative that inflammatory homeostasis is affected at the PU site. There was a marginal influence of intrinsic and extrinsic factors, demonstrating the localised effects of the inflammation. Further studies are required to investigate the potential of inflammatory cytokines incorporated within Point of Care technologies, to support routine clinical use.</p
Spatial and temporal changes in biophysical skin parameters over a category I pressure ulcer
No full textIn acute care facilities, the detection of pressure ulcers (PUs) relies on visual and manual examination of the patient's skin, which has been reported to be inconsistent and may lead to misdiagnosis. In skin and wound research, various biophysical parameters have been extensively employed to monitor changes in skin health. Nonetheless, the transition of these measures into care settings as part of a routine clinical assessment has been limited. This study was designed to examine the spatial and temporal changes in skin biophysical parameters over the site of a category I PU, in a cohort of hospitalised patients. Thirty patients, each presenting with a category I PU, were enrolled in the study. Skin integrity was assessed at the PU-compromised site and two adjacent areas (5 and 10 cm away). Data was collected over three sessions to examine both temporal differences and longitudinal changes. Skin integrity was assessed using two biophysical parameters, namely, transepidermal water loss (TEWL) and stratum corneum (SC) hydration. In addition, the influence of intrinsic factors, namely, incontinence and mobility status, on the parameters was evaluated. TEWL values at the sites compromised by PU were statistically significantly greater (P < .001) than corresponding values at the adjacent control sites at 5 and 10 cm, which were consistent with a normative range (<20 g/h/m
2 ). By contrast, SC hydration values did not reveal clear distinctions between the three sites, with high inter-patient variation detected at the sites. Nevertheless, individual profiles were consistent across the three sessions, and the PU site was observed to be either abnormally dry or overhydrated in different individuals. No consistent temporal trend in either parameter was evident. However, intrinsic factors were shown to influence the parameters, with females, bedridden and incontinent patients presenting significantly higher TEWL and SC hydration values (P < .05). TEWL was able to identify differences in skin responses at skin sites compromised with a category I PU when compared to healthy adjacent skin sites. Accordingly, this parameter could be included in the clinical assessment for the identification of PU risk. Further studies are required to elucidate the role of hydration and skin barrier function in the development of PUs and their ability to monitor temporal changes in skin integrity.
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The effects of incontinence pad application on loaded skin with reference to biophysical and biochemical parameters: an exploratory cohort study using a repeated measure design
No full textPurpose: the purpose of this study was to evaluate temporal changes in skin responses following exposure to moisture alone or moisture in combination with mechanical loading.Design: exploratory cohort study to evaluate the effects of incontinence pad application using a repeated measure design on individuals of two different age groups Subjects and Settings: the sample comprised 12 healthy volunteers. Participants were purposely sampled from two different age groups; 50% were 32 to 39 years and 50% were from 50 to 62 years old. Participants identified as white, black or mixed; 83% (n= 10); 8 (67%) were female.Methods: four sites at the sacrum were challenged with application of specimens taken from two absorbent products; the pad specimens were applied dry or saturated with synthetic urine (SU, pH=8); a further site from the sacral skin was also selected and used as a control. Skin assessments were performed at different points in time: 1.) 60 minutes after exposure to dry or SU saturated pad specimens, 2.) 60 minutes after exposure to pads and mechanical loading (application of pressure in the form of 45⁰C high sitting), and 3.) 30 minutes after removal of all pads (recovery period). Outcome measures were Transepidermal water loss (TEWL), Stratum Corneum (SC) hydration, erythema, pH and skin inflammatory biomarkers measured at each of the time points described above. Results: The control site and those exposed to dry pads showed minimal time-dependent changes irrespective of the parameter investigated. By contrast, significant increases in TEWL (p=0.0000007) and SC hydration responses (p= 0.0000007) were detected at the sites under absorbent pads specimens after saturation with SU (exposure to moisture). In some participants, TEWL and SC hydration parameters were significantly higher during pressure application. Skin pH remained in the mildly acidic range throughout the test session and no consistent trends were observed with erythema. Skin inflammatory biomarkers also exhibited considerable variability across participants with none of the analysed biomarkers presenting significant temporal or spatial changes (p> 0.05). Conclusion: we evaluated an array of parameters to identify changes following skin exposure to two absorbent pads in the presence and absence of synthetic urine and mechanical loading. Analysis revealed changes in skin barrier properties in the presence of moisture and/or pressure. Statistical significant differences (p=0.02) were also detected following the exposure of moisture in combination with pressure. This observation suggests a need for frequent pad changing as well as periods of skin offloading to protect the skin health of individuals with incontinence.<br/
The identification of biophysical parameters which reflect skin status following mechanical and chemical insults
No full textBackground : Skin is constantly exposed to mechanical and chemical insults, in the form of prolonged loading, overhydration or exposure to irritants. An array of non-invasive biophysical tools has been adopted to monitor the changes in skin response. The present study aims to identify a set of robust parameters sensitive to mechanical and chemical challenges to skin integrity. Materials and methods: Eleven healthy participants were recruited to evaluate the skin response following mechanical loading, tape-stripping, overhydration and chemical irritation. Forearm skin responses were recorded at baseline and at three time points following the insult. Measurements included transepidermal water loss, sub-epidermal moisture, erythema and laser Doppler imaging. Thresholds were informed by basal values and the sensitivity of parameters to detect skin changes was evaluated. Results: High degree of variability in skin response was observed with selected biophysical parameters, such as sub-epidermal moisture, laser Doppler imaging and erythema, even in the absence of an applied insult. Temporal skin response revealed distinct response profiles during each evoked insult. Indeed, the sensitivity of the biophysical parameters was influenced by the threshold values and time point of measurement. Some statistically significant correlations were determined between the biophysical parameters.Conclusion: The study revealed that thresholds derived from single biophysical parameters were limited in detecting skin changes following insults. A complementary evaluation using combined parameters has the potential to provide a more sensitive assessment. Further research is required to identify robust biophysical parameters, to aid the early detection of skin damage in clinical settings. <br/
Characterisation of superficial corneocytes in skin areas of the face exposed to prolonged usage of respirators by healthcare professionals during COVID-19 pandemic
No full textIntroductionDuring the COVID-19 pandemic healthcare workers (HCWs) have used respiratory protective equipment for prolonged periods, which has been associated with detrimental effects on the underlying skin. The present study aims to evaluate changes in the main cells (corneocytes) of the stratum corneum (SC) following prolonged and consecutive use of respirators.Methods17 HCWs who wore respirators daily during routine hospital practice were recruited to a longitudinal cohort study. Corneocytes were collected via tape stripping from a negative control site (area outside the respirator) and from the cheek which was in contact with the device. Corneocytes were sampled on three occasions and analysed for the level of positive-involucrin cornified envelopes (CEs) and the amount of desmoglein-1 (Dsg1), as indirect measurements of immature CEs and corneodesmosomes (CDs), respectively. These were compared to biophysical measurements (Transepidermal water loss, TEWL, and SC hydration) at the same investigation sites.ResultsA large degree of inter-subject variability was observed, with maximum coefficients of variation of 43% and 30% for the level of immature CEs and Dsg1, respectively. Although it was observed that there was not an effect of prolonged respirator usage on the properties of corneocytes, the level of CDs was greater at the cheek than the negative control site (p ConclusionsThis is the first study that investigated changes in corneocyte properties in the context of prolonged mechanical loading following respirator application. Although differences were not recorded over time, the levels of CDs and immature CEs were consistently higher in the loaded cheek compared to the negative control site and were positively correlated with a greater number of self-reported skin adverse reactions. Further studies are required to evaluate the role of corneocyte characteristics in the evaluation of both healthy and damaged skin sites
Morphometrics and distribution of antennal sensillae of both sexes of Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae)
No full textFall Armyworm, Spodoptera frugiperda, is a devastating invasive pest persisting as a menace hampering the progress of Indian agriculture. The morphometrics and distribution of antennal sensilla of both sexes of S. frugiperda were investigated in the study. The antenna was filiform for both sexes and was composed of scape, pedicel and flagellum. Male antennas had more subsegments (65-71) in the flagellum than female (56-70) antennas. Male and female S. frugiperda antennae possessed eight types of sensilla: sensilla trichoidea, sensilla chaetica, sensilla coeloconica, sensilla styloconica, sensilla basiconica, sensilla auricillica, sensilla squamiformia and Bӧhm’s bristles. Sensilla trichoidea was the most abundant sensilla found in the antenna of both sexes and was more abundant in males than in females. It was also noticed that male antenna was longer than the female antenna. The results of the present study helps to assess alternative management strategies with an electrophysiological response of the pest towards sex pheromones and in combination with plant info chemicals for monitoring and management of S. frugiperda in agricultural ecosystems.
A lexicographic multiobjective genetic algorithm for optimization of mechanical properties of crab carapace impregnated coir–polyester composites
No full textInfluence of cutting parameters on thrust force and torque in drilling of E-glass/polyester composites
No full text463-470This paper discusses the influence of cutting parameters in drilling of
glass fiber reinforced composites. The experiments are conducted to study the
effect of point angle, spindle speed and feed rate on thrust force and torque using
HSS twist drills. This paper presents a mathematical model for correlating the
interactions of drilling parameters and their effects on thrust force and
torque. The optimum value of cutting parameters is also determined to get
minimum value of thrust force and torque
Regression & neuro fuzzy models for prediction of thrust force and torque in drilling of glass fibre reinforced composites
No full text741-745This study presents drilling
of glass fiber reinforced composites with HSS drill bit to evaluate thrust
force and torque under
different cutting conditions, by using models developed using regression
analysis & Neuro fuzzy system
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