scholarly journals Measurements of transmission of radiation through a non-homogeneous medium, viz., the horny layer of the human skin

1931 ◽  
Vol 109 (763) ◽  
pp. 309-318 ◽  
Keyword(s):  
Human Skin ◽  
Direct Action ◽  
Homogeneous Medium ◽  
Living Cells ◽  
The Body ◽  
Optical Beam ◽  
Single Sample ◽  
Horny Layer ◽  
Humid Condition

The experiments and methods to be described represent an attempt to answer with greater accuracy a question to which somewhat divergent answers have already been given. The entire work herein described was done with a single sample of clear, dry, desquamated, human skin (horny layer only), taken from the shoulder of a woman. This sample had been detached from the body for some months, and no attempt had been made to keep it in a more humid condition than that which it would naturally attain in the air of the laboratory ; but we are indebted to Sir Leonard Hill, at whose instance the work was started, for the opinion that the radiation which penetrates this dead horny layer is the deciding factor in the direct action of radiations on the living cells beneath. The writers found that two precautions are essential : first, to secure truly monochromatic radiations ; secondly, to make allowance for the effects due to the scattering of an optical beam when it is passed through such an uneven medium as a piece of skin. The importance of this last precaution has recently been pointed out by Lucas (1931) and Pearson and Jair (1931).

scholarly journals Population level rhythms in human skin: implications for circadian medicine

2018 ◽  
Author(s):  
Gang Wu ◽  
Marc D. Ruben ◽  
Robert E. Schmidt ◽  
Lauren J. Francey ◽  
David F. Smith ◽  
...  
Keyword(s):  
Human Skin ◽  
Clock Genes ◽  
Human Subjects ◽  
Population Level ◽  
The Body ◽  
Single Sample ◽  
Circadian Phase ◽  
Important Barrier ◽  
Population Scale

AbstractSkin is the largest organ in the body and serves important barrier, regulatory, and sensory functions. Like other tissues, skin is subject to temporal fluctuations in physiological responses under both homeostatic and stressed states. To gain insight into these fluctuations, we investigated the role of the circadian clock in the transcriptional regulation of epidermis using a hybrid experimental design, where a limited set of human subjects (n=20) were sampled throughout the 24 h cycle and a larger population (n=219) were sampled once. By looking at pairwise correlations of core clock genes in 298 skin samples, we found a robust circadian oscillator in skin at the population level. Encouraged by this, we used CYCLOPS to reconstruct the temporal order of all samples and identified hundreds of rhythmically-expressed genes at the population level in human skin. We compared these results with published time-series skin data from mouse and show strong concordance in circadian phase across species for both transcripts and pathways. Further, like blood, skin is readily accessible and a potential source of biomarkers. Using ZeitZeiger, we identified a biomarker set for human skin that is capable of reporting circadian phase to within 3 h from a single sample. In summary, we show rhythms in human skin that persist at the population scale and a path to develop robust single-sample circadian biomarkers.One Sentence SummaryHuman epidermis shows strong circadian rhythms at the population scale and provides a better source for developing robust, single-sample circadian phase biomarkers than human blood.

The history of anabolic steroids and a review of clinical experience with anabolic steroids

1985 ◽  
Vol 110 (3_Suppla) ◽  
pp. S11-S18 ◽  
Author(s):  
H. Kopera
Keyword(s):  
Protein Synthesis ◽  
Protein Metabolism ◽  
Anabolic Steroids ◽  
Muscular Activity ◽  
Living Cells ◽  
Cellular Protein ◽  
Complex Compounds ◽  
The Body ◽  
Anabolic Effect ◽  
Vital Functions

Metabolism is the term employed to embrace the various physical and chemical processes occurring within the tissues upon which the growth and heat production of the body depend and from which the energy for muscular activity, for the maintenance of vital activity and for the maintenance of vital functions is derived (Best & Taylor 1950). The destructive processes by which complex substances are converted by living cells into more simple compounds are called catabolism. Anabolism denotes the constructive processes by which simple substances are converted by living cells into more complex compounds, especially into living matter. Catabolism and anabolism are part of all metabolic processes, the carbohydrate, fat and protein metabolism. The term anabolic refers only to substances that exert an anabolic effect on protein metabolism and are unlikely to cause adverse androgenic effects. They shift the equilibrium between protein synthesis and degradation in the body as a whole in the direction of synthesis, either by promoting protein synthesis or reducing its breakdown. The protein anabolic effect of anabolic steroids is not restricted to single organs but is the result of stimulated biosynthesis of cellular protein in the whole organism.

Antioxidants Reverse Reduction of the Human Hypoxic Ventilatory Response by Subanesthetic Isoflurane

2005 ◽  
Vol 102 (4) ◽  
pp. 747-753 ◽  
Author(s):  
Luc J. Teppema ◽  
Raymonda R. Romberg ◽  
Albert Dahan
Keyword(s):  
Redox State ◽  
Direct Action ◽  
Upper Airway ◽  
The Body ◽  
Alpha Tocopherol ◽  
Hypoxic Response ◽  
Carotid Bodies ◽  
Intravenous Ascorbic Acid ◽  
End Tidal ◽  
Control Sham

Background In subanesthetic concentrations, volatile anesthetics reduce the acute hypoxic response (AHR), presumably by a direct action on the carotid bodies but by an unknown molecular mechanism. To examine a possible involvement of reactive oxygen species or changes in redox state in this inhibiting effect, the authors studied the effect of antioxidants on the isoflurane-induced reduction of the AHR in humans. Methods In 10 volunteers, the authors studied the effect of antioxidants (intravenous ascorbic acid and oral alpha-tocopherol) on the reduction by isoflurane (0.12% end-tidal concentration) of the AHR on a 3-min isocapnic hypoxic stimulus (hemoglobin oxygen saturation 86 +/- 4%). All subjects participated in three separate sessions in which the effects of the antioxidants (session 1), placebo (session 2), and sham isoflurane plus antioxidants (session 3) were tested on the (sham) isoflurane-induced effect on the AHR. Results Isoflurane reduced the acute hypoxic response from 0.82 +/- 0.41 l . min . % to 0.49 +/- 0.23 l . min . % and from 0.89 +/- 0.43 l . min . % to 0.48 +/- 0.28 l . min . % in sessions 1 and 2, respectively (mean +/- SD; P < 0.05 vs. control). This reduction of the AHR was completely reversed by antioxidants (AHR = 0.76 +/- 0.39 l . min . %; not significantly different from control, session 1) but not by placebo in session 2 (AHR = 0.50 +/- 0.30 l . min . %; P < 005 vs. control). Sham isoflurane or antioxidants per se had no effect on the hypoxic response. Conclusions The data indicate that isoflurane may depress the AHR by influencing the redox state of oxygen-sensing elements in the carotid bodies. This finding may have clinical implications for patients who are prone to recurrent hypoxic episodes, e.g., due to upper airway obstruction, in the postoperative period when low-dose isoflurane may persist in the body for some time.

3D Printing of Artificial Skin Patches with Bioactive and Optically Active Polymer Materials for Anti-Infection and Augmenting Wound Repair

2021 ◽  
Author(s):  
Hao Zhao ◽  
Jingwen Xu ◽  
Haitao Yuan ◽  
Endong Zhang ◽  
Nan Dai ◽  
...  
Keyword(s):  
3D Printing ◽  
Human Skin ◽  
Wound Repair ◽  
Optically Active ◽  
The Body ◽  
Polymer Materials ◽  
Artificial Skin ◽  
Optically Active Polymer ◽  
Cell Affinity

Inspired by the skin biofunction of protecting the body from microorganism invasion, artificially manufacturing human skin in vitro with promising antibacterial capability and cell affinity is urgently required in wound...

scholarly journals Population-level rhythms in human skin with implications for circadian medicine

2018 ◽  
Vol 115 (48) ◽  
pp. 12313-12318 ◽  
Author(s):  
Gang Wu ◽  
Marc D. Ruben ◽  
Robert E. Schmidt ◽  
Lauren J. Francey ◽  
David F. Smith ◽  
...  
Keyword(s):  
Human Subjects ◽  
Population Level ◽  
The Body ◽  
Human Epidermis ◽  
Single Sample ◽  
Circadian Phase ◽  
Potential Source ◽  
Pairwise Correlations ◽  
Important Barrier

Skin is the largest organ in the body and serves important barrier, regulatory, and sensory functions. The epidermal layer shows rhythmic physiological responses to daily environmental variation (e.g., DNA repair). We investigated the role of the circadian clock in the transcriptional regulation of epidermis using a hybrid experimental design, in which a limited set of human subjects (n = 20) were sampled throughout the 24-h cycle and a larger population (n = 219) were sampled once. We found a robust circadian oscillator in human epidermis at the population level using pairwise correlations of clock and clock-associated genes in 298 epidermis samples. We then used CYCLOPS to reconstruct the temporal order of all samples, and identified hundreds of rhythmically expressed genes at the population level in human epidermis. We compared these results with published time-series skin data from mice and found a strong concordance in circadian phase across species for both transcripts and pathways. Furthermore, like blood, epidermis is readily accessible and a potential source of biomarkers. Using ZeitZeiger, we identified a biomarker set for human epidermis that is capable of reporting circadian phase to within 3 hours from a single sample. In summary, we show rhythms in human epidermis that persist at the population scale and describe a path to develop robust single-sample circadian biomarkers.

Human Skin Binding and Absorption of Contaminants from Ground and Surface Water During Swimming and Bathing

1989 ◽  
Vol 8 (5) ◽  
pp. 853-859 ◽  
Author(s):  
Ronald C. Wester ◽  
Howard I. Maibach
Keyword(s):  
Surface Water ◽  
Stratum Corneum ◽  
Human Skin ◽  
The Body ◽  
Water Soluble ◽  
Exposure Effect ◽  
Human Stratum Corneum ◽  
Water Dilution

Contaminants exist in ground and surface water. Human skin has the capacity to bind and then absorb these contaminants into the body during swimming and bathing. Powdered human stratum corneum will bind both lipid-soluble (alachlor, polychlorinated biphenyls [PCBs], benzene) and water-soluble (nitroaniline) chemicals. In vitro (human skin) and in vivo (Rhesus monkey) studies show that these chemicals readily distribute into skin, and then some of the chemical is absorbed into the body. Linearity in binding and absorption exists for nitroaniline over a 10-fold concentration range. Multiple exposure to benzene is at least cumulative. Binding and absorption can be significant for exposures as short as 30 min, and will increase with time. Absorption with water dilution increased for alachlor, but not for dinoseb. Soap reversed the partitioning of alachlor between human stratum corneum and water. The PCBs could be removed from skin by soap and water (70% efficiency) for up to 3 h and then decontamination potential decreased, due to continuing skin absorption. The model in vitro and in vivo systems used should permit easy estimation of this area of extensive human exposure effect on risk assessment.

scholarly journals Is mercury injected into the body for therapeutic purposes released into the spinal fluid?

1912 ◽  
Vol XIX (4) ◽  
pp. 803-813
Author(s):  
V. Lazarev
Keyword(s):  
Tuberculous Meningitis ◽  
Nervous Tissue ◽  
Direct Action ◽  
The Body ◽  
Spinal Fluid ◽  
Bile Pigment ◽  
Vascular Plexus ◽  
Points Of View ◽  
The Brain ◽  
Theoretical Side

Is mercury injected into the body excreted into the spinal fluid? This question occupied us with practical and theoretical points of view. On the practical side, we were interested in knowing how much we can count on the circulation of mercury in the spinal fluid and, therefore, on its direct action on the nervous tissue due to the communication of the perivascular (and pericellular) spaces with the sub-arachnoid. If mercury is released into the spinal fluid, it is necessary to search for the therapeutic effect (syphilis of the nervous system) of the drug that quickly and in large quantities passes into the spinal fluid. On the theoretical side, the issue of mercury release is of interest for solving the broader issue of the nature of spinal fluid in general. As is known, there is currently no agreement on this account. Is the spinal fluid transudate, the secretion of the vascular plexus epithelium or the sui generis lymph of the brain itself. In favor of the second1 views are inclined by Schultze, Imamura, Raubitschek, Molt, and others in favor of the last but Spina2 (also Lewandovsky and Blumenthal3. The first view is generally accepted. We thought that the saturation of blood with mercury, which happens with prolonged introduction of it into the body, should lead to the appearance of at least traces of it in the spinal fluid, if the latter is transudate. If the last secret, then apriori nothing can be predicted; extraction depends on the chemical and physical properties of the epithelium itself; the epithelium can secerne one substance and not pass another. The number of substances found so far in the spinal fluid when injected into the body is very limited. When the brain (and membranes) was normal, the substances introduced by the authors did not completely enter the spinal fluid. Widal, Monod4, Sicard was found in tuberculous meningitis iod when giving it during 2-3 days for 3-5 grams only in 3 cases. Guinon and Simon found only 1/2 cases of tuberculous meningitis; no iodine was found in cases of cerebrospinal meningitis. With uremia, Costaigne found iod and methylene blue. Sicard and Widal didnt find it. Gilbert and Castaigne found bile pigment in jaundice. Sicard denies. Archard Loeper5 did not find the lithium when it was injected into the blood. Regarding the fate of mercury introduced into the organism, there are no indications in the literature6.

Evidence for the involvement of peripheral cold-sensitive TRPM8 channels in human cutaneous hygrosensation

2020 ◽  
Vol 318 (3) ◽  
pp. R579-R589 ◽  
Author(s):  
Oliver Typolt ◽  
Davide Filingeri
Keyword(s):  
Human Skin ◽  
Chemical Activation ◽  
The Body ◽  
Cold Sensitivity ◽  
Trpm8 Channel ◽  
Body Regions ◽  
Skin Cooling ◽  
Cold Sensitive ◽  
Skin Wetness

In contrast to other species, humans are believed to lack hygroreceptors for sensing skin wetness. Yet, the molecular basis of human hygrosensation is currently unknown, and it remains unclear whether we possess a receptor-mediated sensing mechanism for skin wetness. The aim of this study was to assess the role of the cutaneous cold-sensitive transient receptor potential melastatin-8 (TRPM8) channel as a molecular mediator of human hygrosensation. To this end, we exploited both the thermal and chemical activation of TRPM8-expressing cutaneous Aδ cold thermoreceptors, and we assessed wetness sensing in healthy young men in response to 1) dry skin cooling in the TRPM8 range of thermosensitivity and 2) application of the TRPM8 agonist menthol. Our results indicate that 1) independently of contact with moisture, a cold-dry stimulus in the TRPM8 range of activation induced wetness perceptions across 12 different body regions and those wetness perceptions varied across the body following regional differences in cold sensitivity; and 2) independently of skin cooling, menthol-induced stimulation of TRPM8 triggered wetness perceptions that were greater than those induced by physical dry cooling and by contact with an aqueous cream containing actual moisture. For the first time, we show that the cutaneous cold-sensing TRPM8 channel plays the dual role of cold and wetness sensor in human skin and that this ion channel is a peripheral mediator of human skin wetness perception.

scholarly journals AN EXPERIMENTAL STUDY OF DIATHERMY

1927 ◽  
Vol 46 (5) ◽  
pp. 715-734 ◽  
Author(s):  
Ronald V. Christie ◽  
Carl A. L. Binger
Keyword(s):  
Electrical Resistance ◽  
High Frequency ◽  
Skin Effect ◽  
Current Flow ◽  
Homogeneous Medium ◽  
Local Heat ◽  
The Body ◽  
Technical Error ◽  
Theoretical Considerations ◽  
Maximal Heating

The principles governing the passage of high frequency currents through various conductors have been discussed and exemplified in experiments done on both non-living and living bodies. In Part I it was shown: (1) That the current takes the path of least electrical resistance rather than the shortest path; (2) that maximal heating occurs at the point of greatest concentration of the lines of current flow. In a homogeneous medium with parallel electrodes maximal heat production occurs in those portions of the medium adjoining the electrodes and the heat gradient is from without inward. Under these circumstances maximal heating never occurs at the center. In discussing the localization of heat not only the electrical resistance and current concentration, but also the cooling effect, must be considered. In experiments on the dog's cadaver no evidence of the so called "skin effect" could be demonstrated. This is in contradistinction to the findings of Bettman and Crohn, but the discrepancy is explained on the basis of what we believe to be a technical error in their work. The finding of no "skin effect" is in agreement with the conclusions of Dowse and Iredell, based on both experimental and theoretical considerations. In Part II three types of experiments were performed on the anesthetized dog. The conclusions to be derived from them are these: (1) The heat gradient of the body is reversed during diathermy and heating occurs from without inward; (2) deep heating during diathermy is greater than that which results from the application of local heat to the skin; (3) the lung can be heated by diathermy in spite of simultaneous cooling of the chest wall. These experiments we regard as satisfactory evidence of the passage of the current through the interior of the body.

scholarly journals Wearable FES Electrodes

Proceedings ◽  
2019 ◽  
Vol 32 (1) ◽  
pp. 13
Author(s):  
Tyler ◽  
Mavridis
Keyword(s):  
Electrical Stimulation ◽  
Human Skin ◽  
Circuit Design ◽  
The Body ◽  
Product Development Process ◽  
Passive Component ◽  
Electrode Size ◽  
Skin Electrode ◽  
Skin Contact ◽  
Electrode Interface

Functional electrical stimulation (FES) has been used to revitalise the muscles of people suffering from various kinds of injury. However, when human skin is incorporated into electrical circuits, it must not be treated as a passive component. Skin’s electrical properties must be known when electrodes deliver electrical stimulation to the body, whether by hydrogel electrodes or by electrodes embedded in apparel. Failure to address this issue increases the risk of skin burns due to too high current through the skin/electrode interface. We have demonstrated that there is a relationship between electrode size and measured voltage. The rise of voltage with a reduction of electrode size can be explained by the diminution of the skin contact area with resulting higher skin/electrode impedances. Thus, finding an electrical skin model that represents the behaviour of human skin is important for circuit design and the product development process.

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