25. Multiple Imputation for Nonresponse in Surveys. By D. B. Rubin. ISBN 0 471 08705 X. Wiley, Chichester, 1987. 258 pp. £30.25.

Multiple Imputation for Nonresponse in Surveys

https://cmapspublic3.ihmc.us/rid=1266358861321_2027852911_13457/Wound%20Healing%20Dressings%20and%20Drug%20Delivery%20Systems.pdf

Wound healing dressings and drug delivery systems: a review.

eMedicine创建于1996年，由近万名临床医师作为作者或编辑参与此临床医学知识库的建设，其中编辑均是来自美国哈佛、耶鲁、斯坦福、芝加哥、德克萨斯、加州大学等各分校医学院的教授或副教授。

eMedicine

Free radical damage is linked to formation of many degenerative diseases, including cancer, cardiovascular disease, cataracts, and aging. Excessive reactive oxygen species (ROS) formation can induce oxidative stress, leading to cell damage that can culminate in cell death. Therefore, cells have antioxidant networks to scavenge excessively produced ROS. The balance between the production and scavenging of ROS leads to homeostasis in general; however, the balance is somehow shifted towards the formation of free radicals, which results in accumulated cell damage in time. Antioxidants can attenuate the damaging effects of ROS in vitro and delay many events that contribute to cellular aging. The use of multivitamin/mineral supplements (MVMs) has grown rapidly over the past decades. Some recent studies demonstrated no effect of antioxidant therapy; sometimes the intake of antioxidants even increased mortality. Oxidative stress is damaging and beneficial for the organism, as some ROS are signaling molecules in cellular signaling pathways. Lowering the levels of oxidative stress by antioxidant supplements is not beneficial in such cases. The balance between ROS and antioxidants is optimal, as both extremes, oxidative and antioxidative stress, are damaging. Therefore, there is a need for accurate determination of individual's oxidative stress levels before prescribing the supplement antioxidants.

/pdf/achieving-the-balance-between-ros-and-antioxidants-when-to-1qwa10120v.pdf

Achieving the Balance between ROS and Antioxidants: When to Use the Synthetic Antioxidants

Many techniques for management of hypertrophic scars and keloids have been proven through extensive use, but few have been supported by prospective studies with adequate control groups. Several new therapies showed good results in small-scale trials, but these have not been repeated in larger trials with long-term follow-up. This article reports a qualitative overview of the available clinical literature by an international panel of experts using standard methods of appraisal. The article provides evidence-based recommendations on prevention and treatment of abnormal scarring and, where studies are insufficient, consensus on best practice. The recommendations focus on the management of hypertrophic scars and keloids, and are internationally applicable in a range of clinical situations. These recommendations support a move to a more evidence-based approach in scar management. This approach highlights a primary role for silicone gel sheeting and intralesional corticosteroids in the management of a wide variety of abnormal scars. The authors concluded that these are the only treatments for which sufficient evidence exists to make evidence-based recommendations. A number of other therapies that are in common use have achieved acceptance by the authors as standard practice. However, it is highly desirable that many standard practices and new emerging therapies undergo large-scale studies with long-term follow-up before being recommended conclusively as alternative therapies for scar management.

International clinical recommendations on scar management.

The effects of chronic sun exposure on skin are readily apparent when skin not typically exposed to the sun and skin regularly exposed to the sun are compared While the sun is not the only aetiological factor in the dynamic process of skin ageing, it is the primary exogenous cause among several internal and environmental elements Thus, photo-ageing, the main focus of this article, is a subset of extrinsic skin ageing The influence of the sun in extrinsic skin ageing, as well as its role in potentially altering the normal course of intrinsic (also known as natural or cellular) ageing, is discussed Telomeres, the specialized structures found at the ends of chromosomes, are believed to be integral to cellular ageing as well as in the development of cancer The ageing process, both intrinsic and extrinsic, is also believed to be influenced by the formation of free radicals, also known as reactive oxygen species The loss of collagen is considered the characteristic histological finding in aged skin Wrinkling and pigmentary changes are directly associated with photo-ageing and are considered its most salient cutaneous manifestations Such photodamage represents the cutaneous signs of premature ageing In addition, deleterious consequences of chronic sun exposure, specifically various forms of photo-induced skin cancer, are also linked to acute and chronic sun exposure The only known strategies aimed at preventing photo-ageing include sun avoidance, using sunscreens to block or reduce skin exposure to UV radiation, using retinoids to inhibit collagenase synthesis and to promote collagen production, and using anti-oxidants, particularly in combination, to reduce and neutralize free radicals

https://onlinelibrary.wiley.com/doi/pdf/10.1002/path.2098

Skin ageing and its treatment

Soft tissue augmentation with temporary dermal fillers is a continuously growing field, supported by the ongoing development and advances in technology and biocompatibility of the products marketed. The longer lasting, less immunogenic and thus more convenient hyaluronic acid (HA) fillers are encompassing by far the biggest share of the temporary dermal filler market. Since the approval of the first HA filler, Restylane, there are at least 10 HA fillers that have been approved by the FDA. Not all of the approved HA fillers are available on the market, and many more are coming. The Juvederm product line (Allergan, Irvine, CA), consisting of Juvederm Plus and Juvederm Ultra Plus, was approved by the FDA in 2006. Juvederm is a bacterium-derived nonanimal stabilized HA. Juvederm Ultra and Ultra Plus are smooth, malleable gels with a homologous consistency that use a new technology called "Hylacross technology". They have a high concentration of cross-linked HAs, which accounts for its longevity. Juvederm Ultra Plus is used for volumizing and correcting deeper folds, whereas Juvederm Ultra is best for contouring and volumizing medium depth facial wrinkles and lip augmentation. Various studies have shown the superiority of the HA filler products compared with collagen fillers for duration, volume needed, and patient satisfaction. Restylane, Perlane, and Juvederm are currently the most popular dermal fillers used in the United States.

/pdf/hyaluronic-acid-gel-juvederm-preparations-in-the-treatment-7pw4kx7xtx.pdf

Hyaluronic acid gel (Juvéderm) preparations in the treatment of facial wrinkles and folds.

BACKGROUNDA new family of next-generation non-animal hyaluronic acid (HA) dermal fillers was approved by the FDA in June 2006. Compared with other HA fillers available in the United States at the time of writing, these new fillers have a higher concentration of HA, higher concentration of cross-link

Comparison of smooth-gel hyaluronic acid dermal fillers with cross-linked bovine collagen: a multicenter, double-masked, randomized, within-subject study.

BACKGROUND Striae distensea (SD; stretch marks) are a well-recognized, common skin condition that rarely causes any significant medical problems but are often a significant source of distress to those affected. The origins of SD are poorly understood, and a number of treatment modalities are available for their treatment, yet none of them is consistently effective, and no single therapy is considered to be pivotal for this problem. With a high incidence and unsatisfactory treatments, stretch marks remain an important target of research for an optimum consensus of treatment. OBJECTIVE To identify the current treatment modalities and their effectiveness in the treatment of stretch marks. MATERIALS AND METHODS Review of the recent literature regarding clinical treatment of stretch marks with emphasis on the safety and efficacy of the newer optical devices and laser applications. RESULTS No current therapeutic option offers complete treatment, although there are a number of emerging new modalities that are encouraging. CONCLUSION The therapeutic strategies are numerous, and no single modality has been far more consistent than the rest. The long-term future of treatment strategies is encouraging with the advance in laser technologies.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1524-4725.2009.01094.x

Striae distensae (stretch marks) and different modalities of therapy: an update.

Treatment of melasma, a hyperpigmentation disorder, remains a challenge. The primary objective of two 8-week, multicenter, randomized, investigator-blind studies was to compare the efficacy and safety of a hydrophilic cream formulation containing tretinoin 0.05%, hydroquinone 4.0%, and fluocinolone acetonide 0.01% (RA+HQ+FA) with the dual-combination agents tretinoin plus hydroquinone (RA+HQ), tretinoin plus fluocinolone acetonide (RA+FA), and hydroquinone plus fluocinolone acetonide (HQ+FA). All agents had the same drug concentration and vehicle. A total of 641 adult patients, predominantly female, with moderate to severe melasma and Fitzpatrick skin types I through IV, were randomized to the various treatment groups. Due to the similarity of the study designs, the results of the 2 studies were combined and are reported here. The primary efficacy analysis involved the proportion of intent-to-treat patients in each treatment group whose condition had completely cleared by week 8. The results of the combined clinical trials demonstrated that significantly more of the patients treated with RA+HQ+FA (26.1%) experienced complete clearing compared with the other treatment groups (4.6%) at the end of week 8 (P<.0001). In addition, at week 8, a 75% reduction in melasma/pigmentation was observed in more than 70% of patients treated with RA+HQ+FA compared with 30% in patients treated with the dual-combination agents. The most common adverse reactions seen with all treatment groups were erythema, skin peeling, burning, and/or stinging sensation. The majority of treatment-related adverse events were of mild severity.

Leslie Baumann

Papers

Skin ageing and its treatment

Hyaluronic acid gel (Juvéderm) preparations in the treatment of facial wrinkles and folds.

Comparison of smooth-gel hyaluronic acid dermal fillers with cross-linked bovine collagen: a multicenter, double-masked, randomized, within-subject study.

Striae distensae (stretch marks) and different modalities of therapy: an update.

Efficacy and safety of a new triple-combination agent for the treatment of facial melasma