867 research outputs found

    An Electron Microscope Study of the Basal Cell Epithelioma

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    At the Digital Doorstep: How Customers Use Doorbell Cameras to Manage Delivery Workers

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    At the Digital Doorstep: How Customers Use Doorbell Cameras to Manage Delivery Workers, by Data & Society's Labor Futures program director Aiha Nguyen and research analyst Eve Zelickson, offers insights into the changing nature of delivery work as a result of increased doorstep surveillance. Investigating the changing relationships between corporations, workers, and customers as a significant share of retail shifts from brick-and-mortar establishments to the doorstep, Nguyen and Zelickson focus on Amazon's fleet of gig workers, known as Flex drivers, and the popular Amazon Ring home security camera

    An Electron Microscope Study of Normal Human Non-Keratinizing Oral Mucosa

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    Melanin Transfer: A Possible Phagocytic Process*

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    The histopathological spectrum of acute generalized exanthematous pustulosis (AGEP) and its differentiation from generalized pustular psoriasis

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    Background: Acute generalized exanthematous pustulosis (AGEP) represents a severe, acute, pustular skin reaction that is most often induced by drugs. AGEP can be difficult to differentiate from generalized pustular psoriasis (GPP) both clinically and histopathologically. We present a systematic description of the histopathological spectrum of AGEP and GPP with a focus on discriminating features. Materials and methods: A retrospective, descriptive, comparative histopathological study was completed utilizing step sections of 43 biopsies of 29 cases with a validated diagnosis of probable or definite AGEP and 24 biopsies of 19 cases with an established diagnosis of GPP. Results: In AGEP, biopsies from erythema and pustules showed minor differences, whereas histopathology of the acute stage of GPP showed major differences compared to the chronic stage. Comparing AGEP and GPP, the presence of eosinophils, necrotic keratinocytes, a mixed interstitial and mid-dermal perivascular infiltrate and absence of tortuous or dilated blood vessels were in favor of AGEP. Moreover, chronic GPP was characterized by prominent epidermal psoriatic changes. The frequency of a psoriatic background of AGEP patients in our study was higher than that of psoriasis in the general population. However, histopathology of a subgroup of AGEP patients with a personal history of psoriasis revealed no significant differences from the other AGEP patients. Conclusions: The spectrum of histopathological features of both AGEP and GPP is presented. Despite considerable overlap, subtle consistent histopathological differences and the grade of severity of specific features can help in differentiation. We could neither substantiate earlier reports that follicular pustules exclude AGEP nor did we see vasculitis as a specific feature in AGEP. Our study also supports the concept that AGEP is a separate entity that is distinct from GPP. Kardaun SH, Kuiper H, Fidler V, Jonkman MF. The histopathological spectrum of acute generalized exanthematous pustulosis (AGEP) and its differentiation from generalized pustular psoriasis

    Molecular mechanisms of nonablative fractionated laser resurfacing

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    Nonablative fractionated laser resurfacing improves the texture of treated skin, but little is known about the molecular mechanisms that underlie clinical improvements.We sought to examine and quantify the time course and magnitude of dermal matrix changes that occur in response to nonablative fractionated laser resurfacing, with the dual goals of better understanding the molecular mechanisms that underlie clinical improvements and of gaining knowledge that will enable evidence-based treatment parameter optimization.Twenty patients (mean age 58 years) with photodamaged skin were focally treated on dorsal forearms with a nonablative fractionated laser. Serial skin samples were obtained at baseline and at various times after treatment. Biopsies were examined with real-time polymerase chain reaction technology and immunohistochemical techniques.Laser treatment resulted in an initial inflammatory response as indicated by statistically significant induction of proinflammatory cytokines (interleukin-1ÎČ and tumour necrosis factor-α). This was followed by substantial increases in levels of several matrix metalloproteinases and later by significant induction of type I collagen. Dermal remodelling was noted with both low and high microbeam energy treatment parameters.Nonablative fractionated laser resurfacing induces a well-organized wound-healing response that leads to substantial dermal remodelling and collagen induction. Surprisingly, only minimal differences were observed between lower and higher microbeam energy settings. These data suggest that lower microbeam energy/higher microbeam density treatment parameters, which are generally better tolerated by patients, may yield dermal changes similar to those that result from higher microbeam energy/lower microbeam density treatment parameters.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79267/1/j.1365-2133.2010.09998.x.pd

    Photothermolysis of sebaceous glands in human skin ex vivo with a 1,708 nm Raman fiber laser and contact cooling

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    Background and Objectives Wavelengths near ∌1,720 nm are of interest for targeting fat/lipid‐rich tissues due to the high absorption coefficient of human fat and low water scattering and absorption. In this study, a 1,708 nm laser was built and shown to selectively target fat/lipid adjacent to porcine heart and dermis and then used to damage dermal sebaceous glands in human skin. Study Design and Materials An all‐fiber 1,708 nm laser with ∌4 W maximum power was designed and built. Selectivity for targeting fat/lipid was studied by exposing porcine heart and skin tissue cross‐sections to the 1,708 nm laser. Human skin treatments to damage sebaceous glands were performed both with and without cold window cooling. Histochemical evaluation on the frozen sections was performed using methylthiazolyldiphenyl‐tetrazolium bromide (MTT) assay. Results Histochemical analysis of porcine tissue cross‐sections showed that 1,708 nm laser can selectively damage pericardial fat(heart) and subcutaneous fat(skin) with little to no damage to the myocardium and the dermis, respectively. In human skin, histochemical evaluation without contact cooling showed damage to both epidermis and dermis. With cooling, epidermis was spared and damage was observed in dermis extending ∌0.4–1.65 mm from the skin surface at an average laser fluence of ∌80 J/cm 2 . Selective damage of sebaceous glands was suggested but not definitively demonstrated. Conclusions We have developed an all‐fiber 1,708 nm laser capable of damaging majority of the sebaceous glands in the dermis and thus may have potential applications in the treatment of conditions such as acne vulgaris whose pathophysiology involves disorders of sebaceous glands. Lasers Surg. Med. 43:470–480, 2011. © 2011 Wiley‐Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87179/1/21085_ftp.pd

    Three-Dimensional Radiofrequency Tissue Tightening: A Proposed Mechanism and Applications for Body Contouring

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    The use of radiofrequency energy to produce collagen matrix contraction is presented. Controlling the depth of energy delivery, the power applied, the target skin temperature, and the duration of application of energy at various soft tissue levels produces soft tissue contraction, which is measurable. This technology allows precise soft tissue modeling at multiple levels to enhance the result achieved over traditional suction-assisted lipectomy as well as other forms of energy such as ultrasonic and laser-generated lipolysis

    Mitochondrial Genetic Background Modulates Bioenergetics and Susceptibility to Acute Cardiac Volume Overload

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    Dysfunctional bioenergetics has emerged as a key feature in many chronic pathologies such as diabetes and cardiovascular disease. This has led to the mitochondrial paradigm in which it has been proposed that mtDNA sequence variation contributes to disease susceptibility. In the present study we show a novel animal model of mtDNA polymorphisms, the MNX (mitochondrial–nuclear exchange) mouse, in which the mtDNA from the C3H/HeN mouse has been inserted on to the C57/BL6 nuclear background and vice versa to test this concept. Our data show a major contribution of the C57/BL6 mtDNA to the susceptibility to the pathological stress of cardiac volume overload which is independent of the nuclear background. Mitochondria harbouring the C57/BL6J mtDNA generate more ROS (reactive oxygen species) and have a higher mitochondrial membrane potential relative to those with C3H/HeN mtDNA, independent of nuclear background. We propose this is the primary mechanism associated with increased bioenergetic dysfunction in response to volume overload. In summary, these studies support the ‘mitochondrial paradigm’ for the development of disease susceptibility, and show that the mtDNA modulates cellular bioenergetics, mitochondrial ROS generation and susceptibility to cardiac stress
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