Postrigor citric acid enhancement can alter cooked color but not fresh color of dark-cutting beef.

In 2 experiments, dark-cutting (DC) beef strip loins were used to test the effects of citric acid-enhancement pH on visual and instrumental color of fresh and cooked steaks. In Exp. 1 and 2, each DC (mean pH = 6.57 and 6.65, respectively) and normal-pH, low USDA Choice (CH; mean pH = 5.48 and 5.51, respectively) strip loin was cut into 2 equal-length sections, and DC sections were injected to 111% of raw section weight with pH 3.5 to 5.0 (Exp. 1) or pH 2.0 to 3.5 (Exp. 2) solutions made by mixing citric acid in either 0.05% orthophosphate (PO) solution or tap water (HO) base solutions (Exp. 1) and 0.5% PO or 0.5% tripolyphosphate solution base solutions (Exp. 2). After enhancement, sections were cut into steaks, which were assigned to either 5 d of simulated retail display or cooked to 71°C for cooked color measurement. Postenhancement pH of DC steaks enhanced with pH 3.5 to 5.0 solutions did not ( ≥ 0.180) differ from that of nonenhanced DC steaks (Exp. 1) but linearly decreased ( < 0.001) as solution pH decreased from 3.5 to 2.0 (Exp. 2). Even though fresh color scores were increased ( < 0.001) by citric acid enhancement over untreated DC steaks during the first 3 d of display, fresh steak color never ( < 0.001) approached that of nonenhanced CH steaks. When compared with nonenhanced DC steaks, enhancement with pH 3.5 to 5.0 solutions received lower cooked color scores, whereas enhancing DC sections with pH 2.5 solutions produced cooked color and degree-of-doneness scores similar ( ≥ 0.113) to those of nonenhanced CH steaks (Exp. 2). Results indicated that the pH of citric acid enhancement solutions, regardless of base solution, were insufficient to improve the fresh color of DC beef; however, enhancement with pH 2.5 citric acid solutions effectively eliminated the persistent red cooked color typically associated with DC beef comparable with that of normal-pH beef.

p19(Arf) is required for the cellular response to chronic DNA damage.

The p53 tumor suppressor is a stress sensor, driving cell cycle arrest or apoptosis in response to DNA damage or oncogenic signals. p53 activation by oncogenic signals relies on the p19(Arf) tumor suppressor, while p53 activation downstream of acute DNA damage is reported to be p19(Arf)-independent. Accordingly, p19(Arf)-deficient mouse embryo fibroblasts (MEFs) arrest in response to acute DNA damage. However, p19(Arf) is required for replicative senescence, a condition associated with an activated DNA damage response, as p19(Arf)-/- MEFs do not senesce after serial passage. A possible explanation for these seemingly disparate roles for p19(Arf) is that acute and chronic DNA damage responses are mechanistically distinct. Replicative senescence may result from chronic, low-dose DNA damage responses in which p19(Arf) has a specific role. We therefore examined the role of p19(Arf) in cellular responses to chronic, low-dose DNA-damaging agent treatment by maintaining MEFs in low oxygen and administering 0.5 G y γ-irradiation daily or 150 µM hydroxyurea, a replication stress inducer. In contrast to their response to acute DNA damage, p19(Arf)-/- MEFs exposed to chronic DNA damage do not senesce, revealing a selective role for p19(Arf) in senescence upon low-level, chronic DNA damage. We show further that p53 pathway activation in p19(Arf)-/- MEFs exposed to chronic DNA damage is attenuated relative to wild-type MEFs, suggesting a role for p19(Arf) in fine-tuning p53 activity. However, combined Nutlin3a and chronic DNA-damaging agent treatment is insufficient to promote senescence in p19(Arf)-/- MEFs, suggesting that the role of p19(Arf) in the chronic DNA damage response may be partially p53-independent. These data suggest the importance of p19(Arf) for the cellular response to the low-level DNA damage incurred in culture or upon oncogene expression, providing new insight into how p19(Arf) serves as a tumor suppressor. Moreover, our study helps reconcile reports suggesting crucial roles for both p19(Arf) and DNA damage-signaling pathways in tumor suppression.

Aging is associated with increased HbA1c levels, independently of glucose levels and insulin resistance, and also with decreased HbA1c diagnostic specificity.

AIM: To determine whether using HbA1c for screening and management could be confounded by age differences, whether age effects can be explained by unrecognized diabetes and prediabetes, insulin resistance or postprandial hyperglycaemia, and whether the effects of aging have an impact on diagnostic accuracy. METHODS: We conducted a cross-sectional analysis in adults without known diabetes in the Screening for Impaired Glucose Tolerance (SIGT) study 2005-2008 (n=1573) and the National Health and Nutrition Examination Survey (NHANES) 2005-2006 (n=1184). RESULTS: Both glucose intolerance and HbA(1c) levels increased with age. In univariate analyses including all subjects, HbA(1c) levels increased by 0.93 mmol/mol (0.085%) per 10 years of age in the SIGT study and by 1.03 mmol/mol (0.094%) per 10 years in the NHANES; in both datasets, the HbA(1c) increase was 0.87 mmol/mol (0.08%) per 10 years in subjects without diabetes, and 0.76 mmol/mol (0.07%) per 10 years in subjects with normal glucose tolerance, all P<0.001. In multivariate analyses of subjects with normal glucose tolerance, the relationship between age and HbA(1c) remained significant (P<0.001) after adjustment for covariates including race, BMI, waist circumference, sagittal abdominal diameter, triglyceride/HDL ratio, and fasting and 2-h plasma glucose and other glucose levels, as assessed by an oral glucose tolerance test. In both datasets, the HbA(1c) of an 80-year-old individual with normal glucose tolerance would be 3.82 mmol/mol (0.35%) greater than that of a 30-year-old with normal glucose tolerance, a difference that is clinically significant. Moreover, the specificity of HbA(1c) -based diagnostic criteria for prediabetes decreased substantially with increasing age (P<0.0001). CONCLUSIONS: In two large datasets, using different methods to measure HbA(1c), the association of age with higher HbA(1c) levels: was consistent and similar; was both statistically and clinically significant; was unexplained by features of aging; and reduced diagnostic specificity. Age should be taken into consideration when using HbA(1c) for the diagnosis and management of diabetes and prediabetes.

Association of physical activity volume and hypercholesterolemia in US adults.

BACKGROUND: Several studies illustrate the favorable association between physical activity (PA) and cholesterol levels. There is a paucity of data examining the PA patterns of individuals with and without hypercholesterolemia (HC). AIM: To examine self-reported moderate and vigorous PA (MVPA) patterns using the most recent PA guidelines among US adults with and without HC. DESIGN: Cross-sectional study utilizing a secondary data analysis approach. METHODS: We used data from the 2009 Behavioral Risk Factor Surveillance System (BRFSS). PA categories were based on the 2008 Department of Health and Human Services (DHHS) guidelines. RESULTS: The age-adjusted prevalence of self-reported HC in US adults was 34%. When stratified by gender, the age-adjusted prevalence of HC was found to be significantly higher in men (36.2%; 95% CI 35.6, 36.8) compared with women (31.8%; 95% CI 31.3, 32.3). The age-adjusted prevalence of meeting the DHHS PA recommendation was 59.1% among participants reporting HC and 68.3% among participants not reporting HC (P < 0.05). Following adjustment for demographics and health history, the odds ratio for meeting the DHHS PA recommendation among participants with HC compared with those without HC was 0.86 (95% CI 0.83, 0.89). CONCLUSION: Although a large proportion of adults reporting HC report engaging in a volume of MVPA necessary to meet national guidelines, their odds of meeting these guidelines and their MVPA volume may be significantly lower than adults who did not report HC.

The pro-longevity gene FoxO3 is a direct target of the p53 tumor suppressor.

FoxO transcription factors have a conserved role in longevity, and act as tissue-specific tumor suppressors in mammals. Several nodes of interaction have been identified between FoxO transcription factors and p53, a major tumor suppressor in humans and mice. However, the extent and importance of the functional interaction between FoxO and p53 have not been fully explored. Here, we show that p53 regulates the expression of FoxO3, one of the four mammalian FoxO genes, in response to DNA damaging agents in both mouse embryonic fibroblasts and thymocytes. We find that p53 transactivates FoxO3 in cells by binding to a site in the second intron of the FoxO3 gene, a genomic region recently found to be associated with extreme longevity in humans. While FoxO3 is not necessary for p53-dependent cell cycle arrest, FoxO3 appears to modulate p53-dependent apoptosis. We also find that FoxO3 loss does not interact with p53 loss for tumor development in vivo, although the tumor spectrum of p53-deficient mice appears to be affected by FoxO3 loss. Our findings indicate that FoxO3 is a p53 target gene, and suggest that FoxO3 and p53 are part of a regulatory transcriptional network that may have an important role during aging and cancer.

Animal-type melanoma: a clinical and histopathological study of 22 cases from a single institution.

Background Animal-type melanoma is a rare distinct melanoma subtype, characterized by proliferation of heavily pigmented epithelioid and spindled melanocytes that resembles the heavily pigmented melanomas seen in grey horses. While animal-type melanoma is generally considered to be more indolent than conventional melanoma, only a limited number of cases have been reported and, as such, the clinical characteristics of animal-type melanoma are incompletely understood. Objectives To characterize the clinical and histopathological features of animal-type melanoma, and determine any features that may predict outcome. Patients/Methods Data was extracted from a prospectively collected melanoma database (1994-2008), and a retrospective pathology database (1991-2008) for all patients with a diagnosis of both equivocal (8) and unequivocal (14) malignant animal-type melanoma. We reviewed the clinical and histopathological features, including the sentinel lymph node biopsy (SLNB) status. Results A total of 22 patients were identified, with a median age of 35 years. The median Breslow depth was 2.22 mm. A SLNB was performed in 17 patients, eight (47%) were positive. Younger age was associated with: (i) animal-type melanoma with features equivocal for malignancy (median age of 7 vs. 48 years, P = 0.01), and (ii) a negative SLNB (median age 12 vs. 53 years, P = 0.03). Four patients with unequivocal animal-type melanoma developed recurrent metastatic disease, with one patient death. No patient with an equivocal animal-type melanoma or negative SLNB developed recurrent disease; however, this did not reach statistical significance (P = 0.13 and P = 0.09, respectively). Conclusions Animal-type melanoma has a propensity for regional lymphatic metastasis and is rarely capable of disseminated metastatic disease and death. Animal-type melanoma appears to exhibit a spectrum of biological behaviour, with young patient age associated with more indolent disease.

Polarized angular dependent spectroscopy of epithelial cells and epithelial cell nuclei to determine the size scale of scattering structures.

An understanding of the relationship between tissue structures and light scattering from tissue will help facilitate the development and acceptance of noninvasive optical diagnostics including elastic scattering spectroscopy, diffuse reflectance, and optical coherence tomography. For example, a quantitative model of the structures that scatter light in epithelial cells would allow determination of what structures control the characteristics of in vivo light transport measurements and subsequently could provide a detailed relationship between cellular structures and optical measurements. We have determined the size distribution of refractive index structure variations in epithelial cells as well as in nuclei isolated from epithelial cells from measurements of the angular dependence of polarized light scattering. The quantitative size distributions we obtained for both whole cells and isolated nuclei include particles with effective radii of 2 microm to 10 nm or less and contain orders of magnitude more small particles than large particles. These results demonstrate that not only are biological cells very heterogeneous, but so are the nuclei within them. Light scattering is likely sensitive to structures smaller than those commonly investigated by standard pathology methods.

Angular dependent light scattering from multicellular spheroids.

We demonstrate that the effects of cell-cell contact and of changes in cell shape have only a minor effect on the angular distribution of light scattering from mammalian fibroblast cells. This result is important for the development of light scattering as a noninvasive tool for tissue diagnostics such as cancer detection. Changes in cell organization that are not accompanied by changes in internal cellular structure may not be measurable. On the other hand, changes in internal cellular structure should be measurable without interference from changes in overall cellular organization. The second major result of this work is that there are small but significant differences between light scattering of tumorigenic and nontumorigenic cells grown in a three-dimensional culture system. The cause of the differences in light scattering are likely due to the nontumorigenic cells arresting in the G1 phase of the cell cycle, while the tumorigenic cells continue to proliferate.

Treatment of head and neck melanoma, lentigo maligna subtype: a practical surgical technique.

Melanoma with the lentigo maligna histological pattern often provides a significant and difficult challenge to the head and neck surgeon. The lentigo maligna subtype is the most common type of melanoma on the head and neck. This potentially lethal form of cancer is associated with greater nonvisual lesional extension that is often not clinically apparent. Failure to excise the entire lesion results in a higher risk of local recurrence and a poorer prognosis. The staged excision technique described herein results in histological interpretation of 100% of the peripheral margins using formalin-fixed vertical sections. Definitive local excision and soft tissue reconstruction are performed in a subsequent stage, with an assurance that 100% of the peripheral margins have been evaluated and interpreted as free of disease.

The forehead flap for nasal reconstruction.

CONTEXT: Reconstruction of extensive nasal defects often represents a significant challenge owing to several unique qualities of the nose, such as complex topography, mobile free margins, and multiple nasal subunits. Furthermore, loss of internal nasal lining and/or structural skeletal support may be present following removal of extensive skin cancers. OBJECTIVE: To describe our experience with the use of forehead flap reconstruction for extensive nasal defects. DESIGN: Retrospective case series. SETTING: Academic health care hospital system. PATIENTS/INTERVENTION: One hundred forty-seven patients with extensive nasal defects repaired with a forehead flap. MAIN OUTCOME MEASURES: The functional and aesthetic results were assessed. The characteristics of defects repaired with the forehead flap and the need for lining and/or cartilage were examined. RESULTS: The forehead flap was used to repair 147 nasal defects after Mohs excision of nonmelanoma skin cancer. Full-thickness skin was lost in all cases, structural skeletal support in 68 cases (46%), and internal mucosal lining in 45 cases (31%). Our experience and surgical technique using the forehead flap are described. CONCLUSIONS: The forehead flap represents one of the best methods for repair of extensive nasal defects. Near-normal functional and cosmetic results can be achieved.

Solitary melanoma confined to the dermal and/or subcutaneous tissue: evidence for revisiting the staging classification.

BACKGROUND: Several patients presented with a single focus of presumed cutaneous metastatic melanoma with an unknown primary tumor based on clinical and histologic staging criteria of the American Joint Committee on Cancer (AJCC). This population is classified as having stage IV disease by the current AJCC staging system, which carries a dismal prognosis (5%-18% 5-year survival). Our clinical observation was that these patients had a higher survival rate than would be expected for stage IV disease. We believe this population represents a subgroup of primary dermal- and or subcutaneously-derived melanoma that simulates cutaneous metastatic melanoma in histologic and clinical presentation but may differ in behavior. OBSERVATIONS: The database records of 1800 patients from the University of Michigan Melanoma Clinic, Ann Arbor, were retrospectively reviewed to identify the prevalence and survival for patients diagnosed with a single focus of presumed metastatic melanoma to the skin based on accepted histologic and clinical parameters. The prevalence of this population was 0.61% (11 of 1800 patients). The Kaplan-Meier 8-year survival estimate was 83% (95% confidence interval, 58%-100%). CONCLUSIONS: By AJCC convention, these cases are classified as stage IV metastatic disease. Our data suggest that these presumed metastatic tumors do not behave like stage IV metastatic disease to the skin via lymphatic or hematogenous spread from an unknown primary site; rather, they are behaving like primary tumors originating in the dermal and/or subcutaneous tissue.

Nasal reconstruction utilizing a muscle hinge flap with overlying full-thickness skin graft.

BACKGROUND: Deep nasal defects of the dorsum, sidewall, and ala can be challenging to repair. OBJECTIVE: The article describes our experience with a muscle hinge transposition flap with overlying local full-thickness skin grafting for repair of deep nasal defects in a single-stage procedure. METHODS: A muscle hinge transposition flap with overlying local full-thickness skin grafting was used immediately after Mohs micrographic surgery to repair 12 deep nasal defects of the dorsum, sidewall, alar lobule, and supratip. RESULTS: No cases of infection, flap, or graft necrosis occurred in our series. Cosmetic and functional outcomes were judged from good to excellent by patient and surgeon. To enhance the cosmetic outcome, 5 patients underwent spot dermabrasion within 2 months of repair. CONCLUSION: For properly selected small to medium-sized deep nasal defects (1-2 cm) that lack a sufficiently loose adjacent tissue reservoir for a single-stage local flap, a muscle hinge transposition flap with local full-thickness skin grafting can provide consistently satisfying aesthetic and functional results.

Modulation of the catalytic activity of the Src family tyrosine kinase Hck by autophosphorylation at a novel site in the unique domain.

Autophosphorylation is a key event in the activation of protein kinases. In this study, we demonstrate that autophosphorylation of the recombinant Src family kinase Hck leads to a 20-fold increase in its specific enzymatic activity. Hck was found to autophosphorylate readily to a stoichiometry of 1.3 mol of phosphate per mol of enzyme, indicating that the kinase autophosphorylated at more than one site. Solid phase sequencing and two-dimensional mapping of the phosphopeptide fragments derived from the autophosphorylated enzyme revealed that the kinase can undergo autophosphorylation at the following two sites: (i) Tyr-388, which is located to the consensus autophosphorylation site commonly found in the activation loop of many protein kinases, and (ii) Tyr-29, which is located in the unique domain of Hck. Hck purified from mouse bone marrow-derived macrophages could also autophosphorylate in vitro at both Tyr-388 and Tyr-29, indicating that naturally occurring Hck can also autophosphorylate at Tyr-29. Furthermore, Hck transiently expressed in human embryonic kidney 293T cells was found to be phosphorylated at Tyr-29 and Tyr-388, proving that Hck can also undergo autophosphorylation at both sites in vivo. The recombinant enzyme carrying the mutation of Tyr-388 to Phe was also able to autophosphorylate at Tyr-29, albeit at a significantly slower rate. A 2-fold increase in the specific enzymatic activity was seen with this mutant despite the stoichiometry of autophosphorylation only approaching 0.2 mol of phosphate per mol of enzyme. This indicates that autophosphorylation of Tyr-29 contributes significantly to the activation of Hck. Regulation of the catalytic activity by phosphorylation of Tyr-29 in the unique domain may represent a new mechanism of regulation of Src family tyrosine kinases.

Changes in youth cigarette use and intentions following implementation of a tobacco control program: findings from the Florida Youth Tobacco Survey, 1998-2000.

CONTEXT: Many states are developing tobacco use prevention and reduction programs, and current data on tobacco use behaviors and how these change over time in response to program activities are needed for program design, implementation, and evaluation. OBJECTIVES: To assess changes in youth cigarette use and intentions following implementation of the Florida Pilot Program on Tobacco Control. DESIGN, SETTING, AND PARTICIPANTS: Self-administered survey conducted prior to program implementation (1998), and 1 and 2 years (1999, 2000) later among a sample of Florida public middle school and high school students who were classified as never users, experimenters, current users, and former users of cigarettes based on survey responses. MAIN OUTCOME MEASURES: Changes in cigarette use status, intentions, and behaviors among students over a 2-year period. RESULTS: Surveys were completed by 22,540, 20,978, and 23, 745 students attending 255, 242, and 243 Florida public middle and high schools in 1998, 1999 and 2000, respectively. Response rates for the 3 survey years ranged from 80% to 82% and 72% to 82% for the middle school and high school surveys, respectively. After 2 years, current cigarette use dropped from 18.5% to 11.1% (P<.001) among middle school students and from 27.4% to 22.6% (P =.01) among high school students. Prevalence of never use increased from 56.4% to 69. 3% (P<.001) and from 31.9% to 43.1% (P =.001) among middle school and high school students, respectively. Prevalence of experimenting decreased among middle school and high school students from 21.4% to 16.2% (P<.001) and from 32.8% to 28.2% (P<.001), respectively. Among never users, the percentage of committed nonsmokers increased from 67.4% to 76.9% (P<.001) and from 73.7% to 79.3% (P<.001) among middle school and high school students, respectively. Among experimenters, the percentage of students who said they will not smoke again increased from 30.4% to 42.0% (P<.001) in middle school and from 44.4% to 51.0% (P<.001) in high school. CONCLUSIONS: Progress toward reduction of youth tobacco use was observed in each of the 2 years of Florida's Pilot Program on Tobacco Control. Our results suggest that a comprehensive statewide program can be effective in preventing and reducing youth tobacco use. JAMA. 2000;284:723-728

Light scattering from cells: the contribution of the nucleus and the effects of proliferative status.

As part of our ongoing efforts to understand the fundamental nature of light scattering from cells and tissues, we present data on elastic light scattering from isolated mammalian tumor cells and nuclei. The contribution of scattering from internal structures and in particular from the nuclei was compared to scattering from whole cells. Roughly 55% of the elastic light scattering at high-angles (> 40 degrees) comes from intracellular structures. An upper limit of 40% on the fractional contribution of nuclei to scattering from cells in tissue was determined. Using cell suspensions isolated from monolayer cultures at different stages of growth, we have also found that scattering at angles greater than about 110 degrees was correlated with the DNA content of the cells. Based on model calculations and the relative size difference of nuclei from cells in different stages of growth, we argue that this difference in scattering results from changes in the internal structures of the nucleus. This interpretation is consistent with our estimate of 0.2 micron as the mean size of the scattering centers in cells. Additionally, we find that while scattering from the nucleus accounts for a majority of internal scattering, a significant portion must result from scattering off of cytoplasmic structures such as mitochondria.

Editing data: what difference do consistency checks make?

In 1998, the Florida Department of Health undertook a self-administered school-based survey of tobacco use, attitudes, and behaviors among nearly 23,000 public school students in grades 6-12. The survey design did not use skip patterns; therefore, students had multiple opportunities to contradict themselves. By using examples from the high school portion (grades 9-12) of the survey, the authors examined five possible approaches to handling data inconsistencies and the effect that each has on point estimates. Use of these approaches resulted in point estimates of current cigarette use ranging from 25.6% to 29.7%. The number of missing respondents varied from 33 (less than 1%) to 1,374 (13%), depending on which approach was used. After stratification by gender and race, the prevalence estimates changed marginally for girls but strikingly for boys. Non-Hispanic White students were substantially more likely than non-Hispanic Black students to report current cigarette use, but the magnitude of this difference varied significantly according to the analytical approach used. The approach used to check data consistency may influence point estimates and comparability with other studies. Therefore, this issue should be addressed when findings are reported.