Metallic taste as a side effect of topical fluorouracil use.

Topical fluorouracil is widely used for the treatment of precancerous and cancerous lesions of the skin. The most common side effect of this medication is localized irritant dermatitis. The authors report a case of dysgeusia with metallic taste as a side effect of this medication. While not previously seen with topical use, this is not an uncommon side effect seen with systemic administration of 5-fluorouracil. The etiology of dysgeusia from chemotherapeutic agents and systemic absorption of fluorouracil is discussed.

Ten-Year Follow-up of Persons With Sun-Damaged Skin Associated With Subsequent Development of Cutaneous Squamous Cell Carcinoma.

Importance: Risk of cutaneous squamous cell carcinoma (cSCC) after the diagnosis of actinic keratosis (AK) has not been studied during long follow-up periods. Objective: To estimate the risk up to 10 years and identify risk factors for cSCC development. Design, Setting, and Participants: This longitudinal cohort study, performed from January 1, 2009, to February 29, 2020, examined Kaiser Permanente Northern California patients with AK and control patients matched 1:1 on age, sex, race/ethnicity, medical center, and date of the initial diagnosis plus 30 days in the patients with AK. Exposures: Patients with AK and control participants were followed up for up to 10 years for incidence of cSCC. Main Outcomes and Measures: Incident cSCC was obtained from pathologic data, and subdistribution hazard ratios (HRs) and 95% CIs were estimated using Cox proportional hazards regression analysis, accounting for competing risks, calendar year, demographic factors, and number of AKs. Results: The study included 220 236 patients with AK and 220 236 matched control patients (mean [SD] age, 64.1 [12.2] years; 231 248 [52.5%] female). After losses to follow-up were accounted for, risk of cSCC increased with each year of follow-up by 1.92% (95% CI, 1.89%-1.95%) in patients with AK and 0.83% (95% CI, 0.81%-0.85%) in matched control patients (subdistribution HR, 1.90; 95% CI, 1.85-1.95). However, among patients 49 years or younger, those diagnosed with AK were nearly 7 times more likely to be diagnosed with cSCC than those without AK (HR, 6.77; 95% CI, 5.50-8.32). At 10 years, the cumulative incidence of cSCC reached 17.1% (95% CI, 16.9%-17.4%) in patients with AK and 5.7% (95% CI, 5.5%-5.9%) in control patients. Increased numbers of AKs were modestly associated with increased cSCC risk (≥15 AKs vs 1 AK: subdistribution HR, 1.89; 95% CI, 1.75-2.04). Older patients had much higher risk of cSCC than younger patients (compared with those ≤49 years of age at AK diagnosis; ≥80 years of age: subdistribution HR, 8.18; 95% CI, 7.62-8.78). Other than AK, risk factors for cSCC included older age, White race (a proxy for skin type), history of basal cell carcinoma, and male sex. Risk decreased between 2009 and 2019 (2018-2019 vs 2009-2010: subdistribution HR, 0.67; 95% CI, 0.63-0.72). Conclusions and Relevance: The results of this longitudinal cohort study can be used to develop recommendations to increase early detection of cSCC. Additional research is needed to understand the effect of AK treatment on cSCC risk and outcomes of cSCC.

Nucleofection is a highly effective gene transfer technique for human melanoma cell lines.

Despite the increasing use of gene transfer strategies in the study of cellular and molecular biology, melanoma cells have remained difficult to transfect in a safe, efficient, and reproducible manner. In the present study, we report the successful use of nucleofector technology to transfect human melanoma cell lines. This technology uses an empirically derived combination of cell line-specific solutions and nucleofector programmes to electroporate nucleic acid substrates directly into the cell nucleus. Using a colorimetric beta-galactosidase assay, we optimized nucleofection parameters for 13 melanoma cell lines, leading to maximum transfection efficiency and cell survival. The combinations of cell solutions NHEM or T and nucleofector programmes A-24 or U-20 produced the best results. We compared nucleofection with two commercially available lipid-based gene transfer systems, effectene and lipofectamine 2000 using a green fluorescent protein reporter vector. Nucleofection demonstrated a 3- to 40-fold improvement in transfection efficiency when compared with the lipid-based counterparts. Nucleofection was also superior in transfecting small-interfering RNA (siRNA) as determined by Western blot analysis. Lastly, we applied nucleofection to the simultaneous transfection of a p53-dependent luciferase plasmid and p53-siRNA. Experiments using dual transfection showed knockdown of p53 expression and silencing of the reporter plasmid. In conclusion, nucleofection is highly effective for the transfer of nucleic acid substrates, singly or in combination, into human melanoma cell lines.

Immunolocalization of KATP channel subunits in mouse and rat cardiac myocytes and the coronary vasculature.

BACKGROUND: Electrophysiological data suggest that cardiac KATP channels consist of Kir6.2 and SUR2A subunits, but the distribution of these (and other KATP channel subunits) is poorly defined. We examined the localization of each of the KATP channel subunits in the mouse and rat heart. RESULTS: Immunohistochemistry of cardiac cryosections demonstrate Kir6.1 protein to be expressed in ventricular myocytes, as well as in the smooth muscle and endothelial cells of coronary resistance vessels. Endothelial capillaries also stained positive for Kir6.1 protein. Kir6.2 protein expression was found predominantly in ventricular myocytes and also in endothelial cells, but not in smooth muscle cells. SUR1 subunits are strongly expressed at the sarcolemmal surface of ventricular myocytes (but not in the coronary vasculature), whereas SUR2 protein was found to be localized predominantly in cardiac myocytes and coronary vessels (mostly in smaller vessels). Immunocytochemistry of isolated ventricular myocytes shows co-localization of Kir6.2 and SUR2 proteins in a striated sarcomeric pattern, suggesting t-tubular expression of these proteins. Both Kir6.1 and SUR1 subunits were found to express strongly at the sarcolemma. The role(s) of these subunits in cardiomyocytes remain to be defined and may require a reassessment of the molecular nature of ventricular KATP channels. CONCLUSIONS: Collectively, our data demonstrate unique cellular and subcellular KATP channel subunit expression patterns in the heart. These results suggest distinct roles for KATP channel subunits in diverse cardiac structures.

Efficacy of a needling device for the treatment of acne scars: a randomized clinical trial.

IMPORTANCE: Neocollagenesis can be achieved using a dermal rolling needle device, thereby reducing the appearance of acne scars. OBJECTIVE: To determine the efficacy of a needling device for treatment of acne scars. DESIGN, SETTING, AND PARTICIPANTS: We performed a single-center, rater-blinded, balanced (1:1), split-face, placebo-controlled, parallel-group randomized clinical trial at an urban academic institution. The study took place from November 30, 2009, through July 27, 2010. Twenty healthy adults (age range, 20-65 years) with acne scars on both sides of the face were enrolled. Fifteen individuals completed the study, and no enrolled participants were withdrawn for adverse effects. INTERVENTIONS: For each participant, one side of the face was randomized for needling. Three needling treatments were performed at 2-week intervals. MAIN OUTCOMES AND MEASURES: Two blinded dermatologists separately rated participants' acne scars based on standard digital photographs obtained at baseline and at the 3-month and 6-month follow-up visits on the quantitative global scarring grading system. RESULTS: Mean scar scores were significantly lower in the treatment group compared with baseline at 6 months (mean difference, 3.4; 95% CI, 0.2-6.5; P = .03) and nominally but not significantly lower compared with baseline at 3 months (mean difference, 2.4; 95% CI, -0.01 to 4.8; P = .052). In the control group, mean scar scores did not vary significantly from baseline at 3 months (mean difference, 1.0; 95% CI, -1.4 to 3.4; P = .96) and at 6 months (mean difference, 0.4; 95% CI, -2.3 to 3.5; P > .99). The needling procedure was not particularly painful, with a mean pain rating of 1.08 of 10. Participants perceived a 41% mean improvement in overall scar appearance on the treated side. No adverse events were reported. CONCLUSIONS AND RELEVANCE: After 3 needling treatments, there was improvement in the appearance of acne scars over time compared with the control group, with minimal pain reported. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00974870.

Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is a rare but aggressive carcinoma of the skin, arising most commonly in sun-exposed sites of elderly patients. The diagnosis is based on characteristic histopathologic features. In 2008, the discovery of the Merkel cell polyomavirus led to intensified research into the viral pathogenesisis of MCC. MCC staging guidelines were established in 2010, and it demonstrated the importance of distinguishing clinical vs. pathologic evaluation of lymph nodes in MCC. Surgery and/or radiation is of the mainstay of therapy for early disease, while chemotherapy is reserved for more advanced disease. Treatments based on immunologic mechanisms are currently in development.

The glycolytic enzymes, glyceraldehyde-3-phosphate dehydrogenase, triose-phosphate isomerase, and pyruvate kinase are components of the K(ATP) channel macromolecular complex and regulate its function.

The regulation of ATP-sensitive potassium (K(ATP)) channel activity is complex and a multitude of factors determine their open probability. Physiologically and pathophysiologically, the most important of these are intracellular nucleotides, with a long-recognized role for glycolytically derived ATP in regulating channel activity. To identify novel regulatory subunits of the K(ATP) channel complex, we performed a two-hybrid protein-protein interaction screen, using as bait the mouse Kir6.2 C terminus. Screening a rat heart cDNA library, we identified two potential interacting proteins to be the glycolytic enzymes, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and triose-phosphate isomerase. The veracity of interaction was verified by co-immunoprecipitation techniques in transfected mammalian cells. We additionally demonstrated that pyruvate kinase also interacts with Kir6.2 subunits. The physiological relevance of these interactions is illustrated by the demonstration that native Kir6.2 protein similarly interact with GAPDH and pyruvate kinase in rat heart membrane fractions and that Kir6.2 protein co-localize with these glycolytic enzymes in rat ventricular myocytes. The functional relevance of our findings is demonstrated by the ability of GAPDH or pyruvate kinase substrates to directly block the K(ATP) channel under patch clamp recording conditions. Taken together, our data provide direct evidence for the concept that key enzymes involved in glycolytic ATP production are part of a multisubunit K(ATP) channel protein complex. Our data are consistent with the concept that the activity of these enzymes (possibly by ATP formation in the immediate intracellular microenvironment of this macromolecular K(ATP) channel complex) causes channel closure.