Comparative nuclear and cellular incorporation of daunorubicin,doxorubicin, carminomycin,marcellomycin, aclacinomycin A and AD 32 in daunorubicin-sensitive and-resistant Ehrlich ascites in vitro

Summary The kinetics of cellular and nuclear incorporation of a number of new anthracyclines into daunorubicin-sensitive and-resistant Ehrlich ascites cells were determined in vitro. For comparative quantitative analyses the substances were extracted with a 0.3 N HCl/50% ethanol (v/v) solution from either whole cells or purified citric acid nuclei after various intervals of in vitro incubation. At steady state the intracellular and intranuclear concentrations of daunorubicin and doxorubicin were reduced by about 50% in the resistant cell line. Marcellomycin and carminomycin concentrations were only reduced by 9% and 11%, respectively, and no differences between sensitive and resistant cells were seen in the case of aclacinomycin A and AD 32. When the ratios of nuclear to cellular drug were determined at steady state lowest value was found for AD 32 (0.26). In contrast, aclacinomycin A and carminomycin were mainly (78% and 74%) and marcellomycin almost exclusively (95%) concentrated in the nucleus. When the total amounts of drug incorporated per cell were compared, the highest values were measured for aclacinomycin A and the lowest for AD 32 both in the sensitive and the resistant tumor. Additional determinations of the 50% inhibitory concentrations for thymidine uptake showed similar differences between these anthracyclines which were not related to the potency of the drugs in vivo. It is concluded that apart from nuclear incorporation and inhibition of DNA synthesis other factors may be decisive for anthracycline-induced cytotoxicity.Supported by a grant from the Deutsche Forschungsgemeinschaft, SFB No. 102, Proj. No. C 2     

Validation of a real-time PCR assay for the detection of bovine herpesvirus 1 in bovine semen

A real-time polymerase chain reaction (PCR) assay was developed for detection of the presence of bovine herpesvirus type 1 (BoHV-1) in extended bovine semen. The assay detects a region encoding a highly conserved glycoprotein B gene. The real-time PCR assay was validated for specificity, sensitivity and repeatability using spiked semen and semen from naturally infected animals. The real-time PCR was very rapid, highly repeatable and more sensitive (lower detection limits) than conventional virus isolation method for the detection of BoHV-1 in extended semen. The specificity of the assay is as expected. The assay had an analytical sensitivity of 0.38 TCID(50) virus spiked into negative semen. The second real-time PCR system for the detection of the bovine growth hormone (bGH) gene was applied as an internal control for the DNA extraction and PCR. The bGH PCR can be performed separately to BoHV-1 PCR, or in a duplex format. The real-time PCR assay is intended for use in international trade. The complete validation dossier based on this study and an international inter-laboratory ring trial has been accredited by the Office International des Epizooties (OIE) and has been recommended to be adopted as a prescribed test for international trade.     

Human platelet-derived growth factor stimulates prostaglandin synthesis by activation and by rapid de novo synthesis of cyclooxygenase.

Human platelet-derived growth factor (PDGF) stimulated prostaglandin (PG) E2 synthesis in the cell cycle of Swiss 3T3 cells at two distinct time intervals, with a first plateau within 10 min and a second plateau within 2-4 h after addition of PDGF. At 4 h, the concentration of PGE2 in PDGF-stimulated cultures exceeded the quiescent control cells by a factor of 10-15. Quiescent cells incubated with up to 16 microM exogenous arachidonic acid (AA) synthesized only small amounts of PGE2. In contrast, 4 h after addition of PDGF, the concentration of PGE2 synthesized from exogenous AA exceeded that in quiescent cultures by a factor of 28. The effect of PDGF stimulation on PG synthesis from exogenous AA could not be explained by growth factor-mediated increase in the cellular free AA pool as shown in experiments using [14C]AA. PDGF also stimulated synthesis of PGI2 (prostacyclin), thromboxane, and PGF2 alpha from exogenous AA. While inhibition of protein synthesis by 10 micrograms/ml cycloheximide had no effect on the early increase in PGE2 synthesis, the second increase was completely prevented. Additionally, cycloheximide treatment at 6 h after PDGF stimulation resulted in rapid decline of PGE2 synthesis from exogenous AA. Quiescent cultures pretreated with 100 microM aspirin and stimulated by PDGF thereafter recovered from cyclooxygenase inhibition within 180 min. Our results suggest that phospholipase activation and resultant AA release is not sufficient to induce the burst of PG synthesis observed in PDGF-stimulated cells. Instead, PDGF stimulates PG synthesis by direct effects on the PG-synthesizing enzyme system, one involving a protein synthesis-independent mechanism and another that requires rapid translation of cyclooxygenase.     

The Transmission of Family Food and Mealtime Practices From Adolescence to Adulthood: Longitudinal Findings From Project EAT-IV

Objective

To determine whether family food and mealtime practices experienced in adolescence are carried forward into parenthood.

Prevalence of Adolescents' Self-Weighing Behaviors and Associations With Weight-Related Behaviors and Psychological Well-Being

PurposeTo examine the relationships between self-weighing frequency, and weight-related behaviors and psychological well-being in a population-based sample of adolescents.MethodsThis study compared weight-related behaviors between infrequent and frequent self-weighers, stratified by weight status and gender. Data were from Project EAT 2010 (Eating and Activity in Teens), a population-based study of 2,778 adolescents.ResultsApproximately 14% of girls and boys weighed themselves frequently (weekly or more). In comparison to girls who were infrequent self-weighers, girls who were frequent self-weighers were more likely to diet, engage in unhealthy and extreme weight control behaviors, use unhealthy muscle-enhancing behaviors, and have lower self-esteem and greater body dissatisfaction. In comparison to boys who were infrequent self-weighers, boys who were frequent self-weighers were more likely to diet, engage in unhealthy and extreme weight control behaviors, use unhealthy muscle-enhancing behaviors, and report greater depressive symptoms. Among overweight adolescents, in addition to being associated with these harmful outcomes, frequent self-weighing was associated with the use of healthy weight control behaviors and with higher levels of moderate-to-vigorous activity.ConclusionsFindings indicate that adolescents who frequently self-weigh themselves are at increased risk for a number of problematic health behaviors and poorer psychological outcomes. For overweight adolescents, frequent self-weighing was additionally associated with a number of positive outcomes. Based upon these findings, any recommendations for weight monitoring should be made cautiously; all adolescents, including overweight adolescents, should be advised not to engage in frequent self-weighing behaviors. Furthermore, any adolescents engaging in frequent self-weighing behaviors should be monitored for problematic outcomes.     

Feeding a Family in a Recession: Food Insecurity Among Minnesota Parents

Objectives. We assessed current levels of food insecurity among a large, diverse sample of parents and examined associations between food insecurity and parental weight status, eating patterns, and the home food environment.Methods. Project F-EAT (Families and Eating and Activity Among Teens) examined the home food environments of adolescents. Parents and caregivers (n = 2095) living with adolescents from the Minneapolis–St. Paul, Minnesota school districts completed mailed surveys during a 12-month period in 2009–2010. We performed our assessments using multivariate regressions.Results. Almost 39% of the parents and caregivers experienced household food insecurity, whereas 13% experienced very low food security. Food insecurity was significantly associated with poorer nutrition-related variables such as higher rates of parental overweight and obesity, less healthy foods served at meals, and higher rates of binge eating. Food-insecure parents were 2 to 4 times more likely to report barriers to accessing fruits and vegetables.Conclusions. Food insecurity was highly prevalent. Environmental interventions are needed to protect vulnerable families against food insecurity and to improve access to affordable, healthy foods.The United States is experiencing the most severe economic collapse since the Great Depression.1,2 By historical standards, unemployment levels remain extremely high3; low-income families, who have been disproportionately burdened by the recession, are struggling to make ends meet.4,5 This financial struggle often results in increased levels of food insecurity—the lack of consistent access to healthy, affordable food.1 Current national estimates suggest 16% of US adults and 25% of US children are food insecure.1,6Common household responses to having inadequate resources for food include food budget adjustments, reduced food intake, and alterations in types of food purchased. Nutrient-dense foods (e.g., fruits, vegetables, whole grains, and lean meats) are significantly more expensive per calorie than are energy-dense foods (e.g., soft drinks, salty and sugary snacks, and pastries).7,8 Thus, studies have shown that in households experiencing food insecurity, food variety tends to decrease and the consumption of energy-dense foods tends to increase.9 A study in Minnesota found that food-insecure youths were more likely to eat fast food and less likely to consume breakfast and family meals than were food-secure youths.10 Poor dietary intake resulting from household food insecurity has been associated with numerous health problems, such as higher rates of diabetes, stress and depression, and hospitalization.11–15 Although the literature is inconsistent,16 food-insecure households, particularly those headed by single mothers, have been found to have higher rates of overweight and obesity.17–19 The concurrent prevalence of obesity and food insecurity is often referred to as the hunger–obesity paradox.20,21Households with children are more likely to be food insecure than are households without children.19,22 Studies have shown that parents, especially mothers, tend to restrict their own intake so enough food will be available for their children.23,24 Additionally, communities of color and immigrant communities experience significantly higher rates of food insecurity compared with the national average.25–27Given the shifts in the economic well-being of the United States, we assessed the current prevalence of food insecurity across sociodemographic characteristics among parents in a large, ethnically diverse population in Minnesota. To better describe implications of current food insecurity among parents, we also examined associations between food insecurity and parental weight status and eating patterns as well as measures of the home food environment.     

Do High-Functioning People with Autism Spectrum Disorder Spontaneously Use Event Knowledge to Selectively Attend to and Remember Context-Relevant Aspects in Scenes?

This study combined an event schema approach with top-down processing perspectives to investigate whether high-functioning children and adults with autism spectrum disorder (ASD) spontaneously attend to and remember context-relevant aspects of scenes. Participants read one story of story-pairs (e.g., burglary or tea party). They then inspected a scene (living room) of which some objects were relevant in that context, irrelevant (related to the non-emphasized event) or neutral (scene-schema related). During immediate and delayed recall, only the (TD) groups selectively recalled context-relevant objects, and significantly more context-relevant objects than the ASD groups. Gaze-tracking suggests that one factor in these memory differences may be diminished top-down effects of event schemas on initial attention (first ten fixations) to relevant items in ASD.