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Developmental Dynamics : An Official... Jul 2022How developing brains mechanically interact with the surrounding embryonic scalp layers (ie, epidermal and mesenchymal) in the preosteogenic head remains unknown....
BACKGROUND
How developing brains mechanically interact with the surrounding embryonic scalp layers (ie, epidermal and mesenchymal) in the preosteogenic head remains unknown. Between embryonic day (E) 11 and E13 in mice, before ossification starts in the skull vault, the angle between the pons and the medulla decreases, raising the possibility that when the elastic scalp is directly pushed outward by the growing brain and thus stretched, it recoils inward in response, thereby confining and folding the brain.
RESULTS
Stress-release tests showed that the E11-13 scalp recoiled and that the in vivo prestretch prerequisite for this recoil was physically dependent on the brain (pressurization at 77-93 Pa) and on actomyosin and elastin within the scalp. In scalp-removed heads, brainstem folding was reduced, and the spreading of ink from the lateral ventricle to the spinal cord that occurred in scalp-intact embryos (with >5 μL injection) was lost, suggesting roles of the embryonic scalp in brain morphogenesis and cerebrospinal fluid homeostasis. Under nonstretched conditions, scalp cell proliferation declined, while the restretching of the shrunken scalp rescued scalp cell proliferation.
CONCLUSIONS
In the embryonic mouse head before ossification, a stretcher-compressor relationship elastically develops between the brain and the scalp, underlying their mechanically interdependent development.
Topics: Animals; Brain; Mice; Scalp; Skull; Spinal Cord; Stretchers
PubMed: 34997665
DOI: 10.1002/dvdy.451 -
Revista Da Associacao Medica Brasileira... Dec 2016Arteriovenous malformations (AVMs) of the scalp are rare lesions. The clinical picture presents with complaints of increased scalp, scalp disfigurement, pain and...
Arteriovenous malformations (AVMs) of the scalp are rare lesions. The clinical picture presents with complaints of increased scalp, scalp disfigurement, pain and neurological symptoms. Its origin can be congenital or traumatic. We present a case of giant scalp AVMs and its management, followed by a brief literature review on the subject. The diagnosis of scalp AVMs is based on physical examination and confirmed by internal and external carotid angiography or computed tomographic angiography (CTA). Surgical excision is especially effective in scalp AVMs, and is the most frequently used treatment modality.
Topics: Adult; Arteriovenous Malformations; Computed Tomography Angiography; Humans; Male; Photography; Scalp
PubMed: 28001255
DOI: 10.1590/1806-9282.62.09.828 -
BMC Microbiology Apr 2023The equilibrium of the scalp microbiome is important for maintaining healthy scalp conditions, including sebum secretion, dandruff, and hair growth. Many different...
BACKGROUND
The equilibrium of the scalp microbiome is important for maintaining healthy scalp conditions, including sebum secretion, dandruff, and hair growth. Many different strategies to improve scalp health have been reported; however, the effect of postbiotics, such as heat-killed probiotics, on scalp health remains unclear. We examined the beneficial effects of heat-killed probiotics consisting of Lacticaseibacillus paracasei, GMNL-653, on scalp health.
RESULTS
Heat-killed GMNL-653 could co-aggregate with scalp commensal fungi, Malassezia furfur, in vitro, and the GMNL-653-derived lipoteichoic acid inhibited the biofilm formation of M. furfur on Hs68 fibroblast cells. The mRNA of hair follicle growth factors, including insulin-like growth factor-1 receptor (IGF-1R), vascular endothelial growth factor, IGF-1, and keratinocyte growth factor was up-regulated in skin-related human cell lines Hs68 and HaCaT after treatment with heat-killed GMNL-653. For clinical observations, we recruited 22 volunteer participants to use the shampoo containing the heat-killed GMNL-653 for 5 months and subsequently measured their scalp conditions, including sebum secretion, dandruff formation, and hair growth. We applied polymerase chain reaction (PCR) to detect the scalp microbiota of M. restricta, M. globosa, Cutibacterium acnes, and Staphylococcus epidermidis. A decrease in dandruff and oil secretion and an increase in hair growth in the human scalp were observed after the use of heat-killed GMNL-653-containing shampoo. The increased abundance of M. globosa and the decreased abundance of M. restricta and C. acnes were also observed. We further found that accumulated L. paracasei abundance was positively correlated with M. globosa abundance and negatively correlated with C. acnes abundance. S. epidermidis and C. acnes abundance was negatively correlated with M. globosa abundance and positively correlated with M. restricta. Meanwhile, M. globosa and M. restricta abundances were negatively associated with each other. C. acnes and S. epidermidis abundances were statistically positively correlated with sebum secretion and dandruff, respectively, in our shampoo clinical trial.
CONCLUSION
Our study provides a new strategy for human scalp health care using the heat-killed probiotics GMNL-653-containing shampoo. The mechanism may be correlated with the microbiota shift.
Topics: Humans; Scalp; Dandruff; Lacticaseibacillus; Lacticaseibacillus paracasei; Hot Temperature; Vascular Endothelial Growth Factor A; Microbiota
PubMed: 37120517
DOI: 10.1186/s12866-023-02870-5 -
Cleveland Clinic Journal of Medicine Sep 2023
Topics: Humans; Scalp; Genitalia; Skin Diseases
PubMed: 37657837
DOI: 10.3949/ccjm.90a.22100 -
Determination of cortisone and cortisol in human scalp hair using an improved LC-MS/MS-based method.Clinical Chemistry and Laboratory... Jan 2024Human scalp hair is an easily available but complex matrix for determination of cortisone and cortisol, and has been shown to reflect long-term glucocorticoid exposure....
OBJECTIVES
Human scalp hair is an easily available but complex matrix for determination of cortisone and cortisol, and has been shown to reflect long-term glucocorticoid exposure. Hair glucocorticoid analysis has been used to detect hypo- and hypercortisolism. In this study, we describe the development and validation of a LC-MS/MS method for quantification of cortisone and cortisol in human scalp hair, and provide a novel approach for analysis and interpretation of the results.
METHODS
Improved sample preparation using pulverization and solid phase extraction allowed for low sample volumes (10 mg). Baseline chromatographic separation without matrix interference was achieved by reversed phase chromatography and MRM measurement in negative ion mode. Run-to-run time was 8 min. Mixed model analyses were performed to create individual patterns of cortisone and cortisol concentrations.
RESULTS
Matrix matched calibration curves showed excellent linearity up to 100 pg (analyte)/mg (hair) for both cortisone and cortisol (R>0.995). LLOQ was 1.5 and 1.0 pg/mg for cortisone and cortisol, respectively. Matrix effect was negligible for hair color (recoveries 95-105 %). Cortisone and cortisol concentrations decreased from proximal to distal hair segments, following a predictable, but subject-specific pattern, with less individual variation for cortisone than for cortisol.
CONCLUSIONS
This improved LC-MS/MS method is able to accurately quantify cortisone and cortisol in human hair with minimum matrix interference. This new way of data analysis and interpretation including individual patterns of cortisone and cortisol will be of help with detection of pathological concentrations in both the high - and the low ranges of glucocorticoids.
Topics: Humans; Hydrocortisone; Cortisone; Chromatography, Liquid; Glucocorticoids; Scalp; Tandem Mass Spectrometry; Hair
PubMed: 37485925
DOI: 10.1515/cclm-2023-0341 -
PloS One 2019Fetal monitoring based on electrocardiographic (ECG) morphology is obtained from a single unipolar fetal scalp electrode. Ideally, it should be obtained from multiple...
BACKGROUND
Fetal monitoring based on electrocardiographic (ECG) morphology is obtained from a single unipolar fetal scalp electrode. Ideally, it should be obtained from multiple leads, as ECG waveform depends on alignment between electrode and electrical heart axis. This alignment is unknown in fetuses. Besides, fetuses are surrounded by conductive media, which may influence ECG waveform. We explored the influence of electrode position and head orientation on ECG waveforms of unipolar and bipolar scalp ECGs recorded in air and in conductive medium.
METHODS
We recorded ECGs in one adult subject at five different scalp positions in five different head orientations both in dry and immersed conditions. The ratio between T-amplitude and QRS-amplitude (T/QRS ratio) of unipolar and bipolar scalp ECGs was determined and compared between all conditions.
RESULTS
In the dry condition, we observed in the unipolar leads little to no difference between different electrode positions (maximal T/QRS difference 0.00-0.01) and minor differences between head orientations (0.02-0.03), whereas bipolar leads showed no recognizable ECG signal at all. During the immersed condition, we found variation in the unipolar leads, both between electrode positions (maximal T/QRS difference 0.02-0.05) and between head orientations (0.03-0.06). Bipolar leads showed different ECG signals in contrasting head orientations.
CONCLUSIONS
Both unipolar and bipolar scalp lead-derived ECG waveforms are influenced by electrode position and head orientation when the subject is submerged in a conductive medium. Fetal monitoring based on single scalp lead ECG waveform might be suboptimal, as it lacks correction for fetal head orientation and electrode position.
Topics: Electrocardiography; Electrodes; Fetus; Humans; Immersion; Scalp; Wavelet Analysis
PubMed: 31600255
DOI: 10.1371/journal.pone.0223282 -
Acta Dermato-venereologica Mar 2023Scalp psoriatic itch is a common, bothersome, yet understudied, condition with numerous associated treatment challenges. The aim of this study was to enhance our...
Scalp psoriatic itch is a common, bothersome, yet understudied, condition with numerous associated treatment challenges. The aim of this study was to enhance our understanding of the pathophysiology of scalp psoriatic itch. Immunohistochemical analysis of known neuroimmune mediators of pruritus was conducted using scalp biopsies from 27 Hispanic psoriatic patients. Patients were categorized into mild/moderate or severe itch groups according to their itch intensity rating of scalp itch. Protease activated receptor (PAR2), substance P, transient receptor potential (TRP)V3, TRPM8 and interleukin-23 expression all correlated significantly with itch intensity. The pathophysiology of scalp psoriasis is largely non-histaminergic, mediated by PAR2, interleukin-23, transient receptor potential channels, and substance P.
Topics: Humans; Scalp; Substance P; Pruritus; Psoriasis; Hispanic or Latino
PubMed: 36967545
DOI: 10.2340/actadv.v103.4463 -
Archives of Dermatological Research Apr 2024Scalp reconstruction requires knowledge of scalp anatomy and reconstructive options. Advances in the field have led to numerous procedures being at the disposal of the... (Review)
Review
BACKGROUND
Scalp reconstruction requires knowledge of scalp anatomy and reconstructive options. Advances in the field have led to numerous procedures being at the disposal of the reconstructive surgeon, expanding treatment options for patients.
OBJECTIVE
To provide an algorithmic approach and general guidelines to consider when deciding on which scalp surgery will optimize cosmetic and functional outcomes.
METHODS & MATERIALS
Previous literature was searched for the last 20 years to provide an updated guide.
RESULTS
Taking into consideration the location, size and local scalp anatomy of a presenting defect will lead to optimal surgical outcomes. Other confounding factors such as bone exposure and extremely large defects will affect decision making. An algorithmic approach has been provided in this review.
CONCLUSION
While many reconstructive surgical options are available, the best ones will depend on individual presentation of scalp defects. Location and size are first line considerations while local scalp anatomy will allow for tailoring of reconstructive options. This will help to maximize cosmetic and aesthetic considerations.
Topics: Humans; Scalp; Plastic Surgery Procedures; Algorithms; Esthetics; Surgical Flaps; Treatment Outcome; Skin Neoplasms
PubMed: 38683230
DOI: 10.1007/s00403-024-02896-3 -
Journal of Neuroengineering and... Jan 2021Transcranial current stimulation in rehabilitation is a fast-growing field featured with computational and biophysical modeling. Cortical features and scalp-to-cortex...
BACKGROUND
Transcranial current stimulation in rehabilitation is a fast-growing field featured with computational and biophysical modeling. Cortical features and scalp-to-cortex distance (SCD) are key variables for determining the strength and distribution of the electric field, yet longitudinal studies able to capture these dynamic changes are missing. We sought to investigate and quantify the ageing effect on the morphometry and SCD of left primary motor cortex (M1) and dorsolateral prefrontal cortex (DLPFC) in normal ageing adults and mild cognitive impairment (MCI) converters.
METHODS
Baseline, 1-year and 3-year follow-up structural magnetic resonance imaging scans from normal ageing adults (n = 32), and MCI converters (n = 22) were drawn from the Open Access Series of Imaging Studies. We quantified the changes of the cortical features and SCDs of left M1 and DLPFC, including grey matter volume, white matter volume, cortical thickness, and folding. Head model was developed to simulate the impact of SCD on the electric field induced by transcranial current stimulation.
RESULTS
Pronounced ageing effect was found on the SCD of left DLPFC in MCI converters. The SCD change of left DLPFC from baseline to 3-year follow-up demonstrated better performance to discriminate MCI converters from normal ageing adults than the other morphometric measures. The strength of electric field was consequently decreased with SCD in MCI converters.
CONCLUSION
Ageing has a prominent, but differential effect on the region-specific SCD and cortical features in older adults with cognitive impairments. Our findings suggest that SCD, cortical thickness, and folding of the targeted regions could be used as valuable imaging markers when conducting transcranial brain stimulation in individuals with brain atrophy.
Topics: Aged; Aging; Atrophy; Cognitive Dysfunction; Computer Simulation; Female; Humans; Magnetic Resonance Imaging; Male; Motor Cortex; Prefrontal Cortex; Scalp; Transcranial Magnetic Stimulation
PubMed: 33397402
DOI: 10.1186/s12984-020-00764-5 -
Biomedical Engineering Online Aug 2017A problem inherent to recording EEG is the interference arising from noise and artifacts. While in a laboratory environment, artifacts and interference can, to a large...
BACKGROUND
A problem inherent to recording EEG is the interference arising from noise and artifacts. While in a laboratory environment, artifacts and interference can, to a large extent, be avoided or controlled, in real-life scenarios this is a challenge. Ear-EEG is a concept where EEG is acquired from electrodes in the ear.
METHODS
We present a characterization of physiological artifacts generated in a controlled environment for nine subjects. The influence of the artifacts was quantified in terms of the signal-to-noise ratio (SNR) deterioration of the auditory steady-state response. Alpha band modulation was also studied in an open/closed eyes paradigm.
RESULTS
Artifacts related to jaw muscle contractions were present all over the scalp and in the ear, with the highest SNR deteriorations in the gamma band. The SNR deterioration for jaw artifacts were in general higher in the ear compared to the scalp. Whereas eye-blinking did not influence the SNR in the ear, it was significant for all groups of scalps electrodes in the delta and theta bands. Eye movements resulted in statistical significant SNR deterioration in both frontal, temporal and ear electrodes. Recordings of alpha band modulation showed increased power and coherence of the EEG for ear and scalp electrodes in the closed-eyes periods.
CONCLUSIONS
Ear-EEG is a method developed for unobtrusive and discreet recording over long periods of time and in real-life environments. This study investigated the influence of the most important types of physiological artifacts, and demonstrated that spontaneous activity, in terms of alpha band oscillations, could be recorded from the ear-EEG platform. In its present form ear-EEG was more prone to jaw related artifacts and less prone to eye-blinking artifacts compared to state-of-the-art scalp based systems.
Topics: Artifacts; Blinking; Ear; Electrodes; Electroencephalography; Eye Movements; Head; Humans; Scalp; Signal-To-Noise Ratio
PubMed: 28800744
DOI: 10.1186/s12938-017-0391-2