Activation of the PI3K/Akt/mTOR and MAPK Signaling Pathways in Response to Acute Solar-Simulated Light Exposure of Human Skin.

The incidence of skin cancer is higher than all other cancers and continues to increase, with an average annual cost over $8 billion in the United States. As a result, identifying molecular pathway alterations that occur with UV exposure to strategize more effective preventive and therapeutic approaches is essential. To that end, we evaluated phosphorylation of proteins within the PI3K/Akt and MAPK pathways by immunohistochemistry in sun-protected skin after acute doses of physiologically relevant solar-simulated ultraviolet light (SSL) in 24 volunteers. Biopsies were performed at baseline, 5 minutes, 1, 5, and 24 hours after SSL irradiation. Within the PI3K/Akt pathway, we found activation of Akt (serine 473) to be significantly increased at 5 hours while mTOR (serine 2448) was strongly activated early and was sustained over 24 hours after SSL. Downstream, we observed a marked and sustained increase in phospho-S6 (serine 235/S236), whereas phospho-4E-BP1 (threonines 37/46) was increased only at 24 hours. Within the MAPK pathway, SSL-induced expression of phospho-p38 (threonine 180/tyrosine 182) peaked at 1 to 5 hours. ERK 1/2 was observed to be immediate and sustained after SSL irradiation. Phosphorylation of histone H3 (serine 10), a core structural protein of the nucleosome, peaked at 5 hours after SSL irradiation. The expression of both p53 and COX-2 was increased at 5 hours and was maximal at 24 hours after SSL irradiation. Apoptosis was significantly increased at 24 hours as expected and indicative of a sunburn-type response to SSL. Understanding the timing of key protein expression changes in response to SSL will aid in development of mechanistic-based approaches for the prevention and control of skin cancers.

Malondialdehyde-derived epitopes in human skin result from acute exposure to solar UV and occur in nonmelanoma skin cancer tissue.

Cutaneous exposure to solar ultraviolet radiation (UVR) is a causative factor in photoaging and photocarcinogenesis. In human skin, oxidative stress is widely considered a key mechanism underlying the detrimental effects of acute and chronic UVR exposure. The lipid peroxidation product malondialdehyde (MDA) accumulates in tissue under conditions of increased oxidative stress, and the occurrence of MDA-derived protein epitopes, including dihydropyridine-lysine (DHP), has recently been substantiated in human skin. Here we demonstrate for the first time that acute exposure to sub-apoptogenic doses of solar simulated UV light (SSL) causes the formation of free MDA and protein-bound MDA-derived epitopes in cultured human HaCaT keratinocytes and healthy human skin. Immunohistochemical staining revealed that acute exposure to SSL is sufficient to cause an almost twenty-fold increase in general MDA- and specific DHP-epitope content in human skin. When compared to dose-matched solar simulated UVA, complete SSL was more efficient generating both free MDA and MDA-derived epitopes. Subsequent tissue microarray (TMA) analysis revealed the prevalence of MDA- and DHP-epitopes in nonmelanoma skin cancer (NMSC). In squamous cell carcinoma tissue, both MDA- and DHP-epitopes were increased more than threefold as compared to adjacent normal tissue. Taken together, these date demonstrate the occurrence of MDA-derived epitopes in both solar UVR-exposed healthy human skin and NMSC TMA tissue; however, the potential utility of these epitopes as novel biomarkers of cutaneous photodamage and a functional role in the process of skin photocarcinogenesis remain to be explored.

Trends in post-mastectomy reconstruction: a SEER database analysis.

BACKGROUND AND OBJECTIVES: This study was performed to investigate recent trends and factors associated with immediate breast reconstruction (IBR) using a large population-based registry. We hypothesized that rates of IBR have increased since passage of the Women's Health and Cancer Rights Act of 1998. METHODS: The SEER (surveillance, epidemiology and end results) database was used to evaluate Stage I-III breast cancer (BC) patients who underwent total mastectomy from 1998 to 2008. Univariate and multivariate analyses were performed to study predictors of IBR. RESULTS: Of 112,348 patients with BC treated by mastectomy 18,001 (16%) had IBR. Rates of IBR increased significantly from 1998 to 2008 (P < 0.0001). Use of IBR significantly decreased as patient age increased (P < 0.0001), as stage increased (P < 0.0001), and as the number of positive lymph nodes increased (P < 0.0001). Estrogen receptor+/progesterone receptor+ (ER+/PR+) patients had significantly higher IBR rates than ER-/PR-patients (P < 0.0001). IBR was used in 3,615 of 25,823 (14.0%) of patients having post-mastectomy radiation (XRT) and in 14,188 of 86,513 (16.4%) of those not having XRT (P < 0.0001). CONCLUSIONS: The utilization of IBR has increased significantly over the last decade. IBR was found to be significantly associated with age, race, geographical region, stage, ER, grade, LN status, and XRT (P < 0.0001).

Surgical cephalometrics: applications and developments.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Describe the historical origins of modern cephalometry. 2. Identify common landmark points on the lateral cephalogram. 3. Describe multiple common clinical uses for cephalometry. 4. Exhibit knowledge of developments in imaging and analysis alternatives. BACKGROUND: Interest in the dimensions of the human head has been present since antiquity. Proportional analysis and measures from cadaveric specimens led to the development of radiologic image capture and analysis on living subjects. These techniques were originally applied to establishing normative values, documenting growth, and diagnosing dentofacial disharmonies. This article reviews the origins of cephalometric methodology and current developments and applications. METHODS: The authors conducted a MEDLINE search and review of all English language articles using the keywords "cephalometric" and "cephalometrics." RESULTS: Cephalometrics have undergone substantial use and development since the introduction of radiologic imaging on living human subjects in 1931. Although frequently associated with orthognathic surgery, cephalometrics have been applied to a number of conditions involving altered craniofacial morphology. Advances in imaging and computing have led to increased interest in three-dimensional and non-x-ray-based assessment of the human head. Mathematical models have been applied to standard cephalometric information to increase the descriptive accuracy of the complex shapes involved. CONCLUSIONS: Cephalometric techniques and analyses are versatile tools that can be applied to a wide variety of clinical scenarios involving the craniofacial region. New technologies and expanded applications promise to continue the development and use of this well-established methodology.

The deep inferior epigastric artery: anatomy and applicability as a source of microvascular arterial grafts.

BACKGROUND: Arterial grafts are superior to venous grafts when used for microvascular grafting procedures. Advantages of arterial grafts include anatomical taper, improved size match, improved handling characteristics, and superior patency rates. The deep inferior epigastric artery may be used as a source of microvascular graft to replace damaged or diseased arterial segments. By studying cadaver dissections, it is possible to estimate the clinically usable length and caliber of the deep inferior epigastric artery. METHODS: Thirty-four preserved cadavers were dissected and 63 deep inferior epigastric arterial systems were removed and measured. The deep inferior epigastric artery was used as an arterial conduit to bypass across nine wrists in eight patients. RESULTS: The mean length from the external iliac artery to the point at which the vessel displayed an external diameter of 1 mm was 14.06 +/- 2.54 cm. The deep inferior epigastric artery has been used in nine clinical cases as an arterial conduit to bypass distal to the wrist. All nine bypasses were patent 1 year postoperatively, without donor-site complication. CONCLUSION: The deep inferior epigastric artery is a morphologically reliable and clinically useful source of arterial grafts.