Morphological parametric mapping of 21 skin sites throughout the body using optical coherence tomography

Background Changes in body posture cause changes in morphological properties at different skin sites. Although previous studies have reported the thickness of the skin, the details of the postures are not generally given. This paper presents the effect of a change in posture on parameters such as thickness and surface roughness in 21 load-bearing and non-load-bearing sites. Materials and methods A total of 12 volunteers (8 males and 4 females) were selected in an age group of 18–35 years and of Fitzpatrick skin type I-III. Images were captured using a clinically-approved VivoSight® optical coherence tomography system and analysed using an algorithm provided by Michelson Diagnostics. Results Overextension (extending joints to full capacity) resulted in changes to thickness, roughness and undulation of the skin around the body. Discussion and conclusion The load-bearing regions have thicker skin compared to non-load-bearing sites. This is the first time that undulation topography of the stratum corneum–stratum lucidum and the dermal–epidermal junction layers have been measured and reported using statistical values such as Ra. The data presented could help to define new skin layer models and to determine the variability of the skin around the body and between participants

Meat freshness revealed by visible to near-infrared spectroscopy and principal component analysis

Increasing concerns about adulterated meat encouraged industry looking for new non-invasive methods for rapid accurate meat quality assessment. Main meat chromophores (myoglobin, oxy-myoglobin, fat, water, collagen) are characterized by close comparable absorption in visible to near-infrared (NIR) spectral region. Therefore, structural and compositional variations in meat may lead to relative differences in the absorption of light. Utilizing typical fiber-optic probes and integrating sphere, a degradation of pork samples freshness was observed at room temperature referring to the relative changes in absorbance of main meat chromophores. The application of principal component analysis (PCA) used for examination of measured absorbance spectra revealed more detailed sub-stages of freshness, which are not observed by the conventional analysis of the reflectance spectra. The results show a great potential of the combined application of optical-NIR spectroscopy with complementary use of PCA approach for assessing meat quality and monitoring relative absorbance alternation of oxymyoglobin and myoglobin in visible, and fat, water, collagen in NIR spectral ranges

Imaging of 3D tissue-engineered models of oral cancer using 890 and 1300 nm optical coherence tomography

© 2015, Nizhny Novgorod State Medical Academy. All rights reserved. Optical coherence tomography (OCT) generates its primary form of contrast from elastic backscatter. It is now the gold standard technique for retinal screening and is emerging rapidly in cardiovascular research however it remains a research goal to establish it to the same degree in epithelial cancer detection and diagnosis. In this report we compare two different OCT systems: an 890 nm spectrometer-based OCT system with 2.5 µm axial resolution and a 1300 nm swept-source OCT system with 7.5 µm axial resolution to determine the effect of these different OCT parameters on the endogenous backscatter contrast of dysplastic/malignant oral mucosa models relative to normal mucosa models. Tissueengineered oral mucosa models constructed with a dysplastic cell line (DOK), a malignant cell line (Cal27) and normal cell were imaged with both of these OCT platforms and comparisons made with regard to apparent epithelial thickness and the visibility of the epithelium relative to the underlying stroma. For the Cal27’s, hematoxylin and eosin staining confirmed the formation of a keratinized layer superficial to a thickened layer of viable cells on top of the stroma. The keratinized layer presented as a hyperreflective thickened layer superficial to a darker region on both OCT platforms. The keratinized layer caused a steep fall in signal at 890 nm, making it difficult to visualise underlying structures, whereas 1300 nm OCT clearly visualized both the epithelial cells and the stroma lying beneath. For the DOK cells, hematoxylin and eosin staining confirmed the formation of an epithelial layer frequently presenting an abnormal morphology especially at the epidermal/stromal junction, with features such as infiltrating, bulbous rete pegs. These were more clearly visualized under 890 nm OCT. These observations show that 890 nm OCT retains some of its known advantages of higher contrast between anatomical tissue layers when used to observe dysplastic and malignant 3D oral mucosa constructs. However 1300 nm OCT is confirmed to possess a greater ability to image the full thickness of the model epithelia and in particular it is more suited to imaging through the keratinized layer

Translating optical coherence tomography technologies from clinical studies to botany : real time imaging of long-distance signaling in plants

The time has now come to expand the use of optical coherence tomography and apply it in botany where the technology’s key advantages enable visualization of plant’s communication as it was never done before

Improvements in Skeletal Muscle Can Be Detected Using Broadband NIRS in First-Time Marathon Runners

Skeletal muscle metabolic function is known to respond positively to endurance exercise interventions, such as marathon training. Studies investigating skeletal muscle have typically used muscle biopsy samples or magnetic resonance spectroscopy (MRS) to interrogate metabolic function. We aimed to non-invasively detect exercise-training-induced improvements in muscle function using broadband near-infrared spectroscopy (NIRS). We used NIRS to determine concentration changes in oxygenated haemoglobin (HbO2) and the oxidation state of cytochrome-c-oxidase (oxCCO) in gastrocnemius during arterial occlusion in 14 volunteers. We also used a cardio-pulmonary exercise test (CPET) to assess peak total body oxygen uptake (peakVO2; a measure of fitness). Measurements were made at baseline (BL) which was prior to a period of at least 16 weeks of training for the 2017 London Marathon, and then within 3 weeks after completion of the marathon, follow-up (FU). We observed an increase in locally measured muscle oxygen consumption and rate of oxCCO concentration change, but not in cardio-respiratory fitness measured as whole-body peak oxygen consumption (peakVO2)

In Vivo Measurement of Cerebral Mitochondrial Metabolism Using Broadband Near Infrared Spectroscopy Following Neonatal Stroke

Neonatal stroke presents with features of encephalopathy and can result in significant morbidity and mortality. We investigated the cerebral metabolic and haemodynamic changes following neonatal stroke in a term infant at 24 h of life. Changes in oxidation state of cytochrome-c-oxidase (oxCCO) concentration were monitored along with changes in oxy- and deoxy- haemoglobin using a new broadband near-infrared spectroscopy (NIRS) system. Repeated transient changes in cerebral haemodynamics and metabolism were noted over a 3-h study period with decrease in oxyhaemoglobin (HbO2), deoxy haemoglobin (HHb) and oxCCO in both cerebral hemispheres without significant changes in systemic observations. A clear asymmetry was noted in the degree of change between the two cerebral hemispheres. Changes in cerebral oxygenation (measured as HbDiff=HbO2-HHb) and cerebral metabolism (measured as oxCCO) were highly coupled on the injured side of the brain

Enhancing African coelacanth monitoring using environmental DNA

Coelacanths are rare, elusive, ancient lobe-finned fish species, residing in poorly accessible tropical marine caves and requiring close monitoring and protection. Environmental DNA (eDNA) approaches are being increasingly applied in the detection of rare and threatened species. Here we devise an eDNA approach to detect the presence of African coelacanths (Latimeria chalumnae) off the eastern coast of South Africa. Novel coelacanth-specific primers were designed to avoid cross-amplification with other fish lineages and validated for specificity. These primers were tested on field samples in conjunction with remotely operated vehicle (ROV) visual surveys. Samples were collected from a known coelacanth habitat and two adjacent slope habitats a few kilometres apart. Coelacanth DNA was detected from three of 15 samples collected. Two of these positive eDNA detections occurred in the presence of coelacanths, as evidenced by ROV footage, while the third positive detection was at a station where coelacanths had not been previously observed. eDNA detections are discussed in relation to the species’ metabolic rate, movement patterns and population size, as well as the local oceanographic features. We demonstrate that eDNA can provide a non-invasive method to extend the knowledge of coelacanth distribution ranges and boost research efforts around these iconic fishes

Evaluating the use of optical coherence tomography for the detection of epithelial cancers in vitro

Optical coherence tomography (OCT) is a noninvasive imaging methodology that is able to image tissue to depths of over 1 mm. Many epithelial conditions, such as melanoma and oral cancers, require an invasive biopsy for diagnosis. A noninvasive, real-time, point of care method of imaging depth-resolved epithelial structure could greatly improve early diagnosis and long-term monitoring in patients. Here, we have used tissue-engineered (TE) models of normal skin and oral mucosa to generate models of melanoma and oral cancer. We have used these to determine the ability of OCT to image epithelial differences in vitro. We report that while in vivo OCT gives reasonable depth information for both skin and oral mucosa, in vitro the information provided is less detailed but still useful. OCT can provide reassurance on the development of TE models of skin and oral mucosa as they develop in vitro. OCT was able to detect the gross alteration in the epithelium of skin and mucosal models generated with malignant cell lines but was less able to detect alteration in the epithelium of TE models that mimicked oral dysplasia or, in models where tumor cells had penetrated into the dermis

Potential application of PS-OCT in the safety assessment of non-steroidal topical creams for atopic dermatitis treatment

Crisaborole 2% ointment is a non-steroidal treatment for mild-moderate atopic dermatitis (AD) and may produce fewer adverse effects than topical corticosteroids (TCS). We used PS-OCT to quantify dermal collagen at baseline and after 29 days of treatment with crisaborole and betamethasone valerate (BMV), in 32 subjects. PS-OCT detected a mean increase 1 × 10-6, 95% CI (6.3, 1.37) × 10-6 in dermal birefringence following TCS use (p < 0.0001, ad-hoc, not powered), whereas a change of -4 × 10-6, 95% CI (-32, 24) × 10-6 was detected for crisaborole (p = 0.77, ad-hoc, not powered). These results could suggest a differential effect on dermal collagen between the two compounds. PS-OCT may thus find an important role in safety assessment of novel AD treatment’ and larger trials are warranted

Evaluation of Haemoglobin and Cytochrome Responses During Forearm Ischaemia Using Multi-wavelength Time Domain NIRS

We demonstrate the ability of a 16-wavelength time domain near-infrared spectroscopy system to monitor changes in oxy- and deoxy haemoglobin ([HbO2] [HHb]) and the oxidation of cytochrome-c-oxidase ([oxCCO]), during forearm ischaemia. We tested two methods to retrieve the concentration changes. The first uses the measured changes in light attenuation and the modified Beer-Lambert law, and the second uses the absorption and scattering estimated by the measured time-point spread function. The system is able to retrieve the concentration changes with both methods, giving similar results. At the end of forearm ischaemia (t = 5 min), we measured an increase in [HHb] of 16.77 ± 2.52 and 16.37 ± 2.33 μMol, and a decrease in [HbO2] of -6.12 ± 1.62 and -5.57 ± 2.02 μMol for method 1 and 2, respectively. At that same time, the changes in [oxCCO] were -0.36 ± 0.33 and -1.40 ± 1.20 μMol, for method 1 and 2, respectively. These small changes in [oxCCO], despite a huge change in haemoglobin, demonstrate the absence of crosstalk and are comparable to previous measurements using broadband NIRS