The association of food sources of calcium with weight class in adolescent girls

To determine the association of food sources of calcium with weight class in adolescent girls, the major food sources of calcium were determined for 718 sixth grade girls at three different time periods during an 18 month school-based health intervention program using a FFQ. To determine weight class, the BMI of each girl was stratified using CDC age and gender specific criteria at each time period. The percent contribution of the major food sources of calcium to total calcium intake was compared among the different weight classes at each time period, among those girls who had changed weight class at the different time periods and for those girls who did not change weight class at the different time periods. The mean total calcium intake increased by 20% between the first two time periods and by 12% between the first and last time periods with the intervention despite baseline total calcium intake already being greater than the recommended 1300 mg/day. The percent contribution of the major food sources of calcium were highly correlated among the weight classes that were compared throughout the study. Those girls who remained in the normal weight class throughout the study had the most consistent intake of food sources of calcium. Their top four food sources of calcium were different types of milk which provided greater than 50% of their total calcium intake. Despite there being no significant differences in the major food sources of calcium among the different weight classes, these data show a successful intervention for increasing calcium intake among adolescent girls. ^

The role of cardiorespiratory fitness and weight status on 24-hr ambulatory blood pressure among adolescents

BACKGROUND: This observational research study investigated the association of cardiorespiratory fitness and weight status with repeated measures of 24-hr ambulatory blood pressure (24-hr ABP). Little is known about these associations and few data exist examining the interaction between cardiorespiratory fitness and weight status and the contributions of each on 24-hr ABP in youth. ^ METHODS: This research study used secondary analysis data from the "Adolescent Blood Pressure and Anger: Ethnic Differences" study. This current study sample included 374 African-American, Anglo-American, and Mexican-American adolescents 11-16 years of age. Mixed-effects models were used for testing the relationship between weight status and cardiorespiratory fitness and repeated measures of ambulatory blood pressure over 24 hours (24-hr ABP). Weight status was categorized into "normal weight" (BMI<85th percentile), "overweight" (85th≤BMI<95th), and "obese" (BMI≥95th). Cardiorespiratory fitness, determined by heart rate recovery (HRR), was defined as the difference between heart rate at peak exercise and heart rate at two minutes post-exercise, as measured by a height-adjusted step test and stratified into two groups: low and high fitness, using a median split. Ambulatory blood pressure (ABP) was monitored for a 24-hr period on a school day using the Spacelabs ambulatory monitor (Model 90207). Blood pressure and heart rate were recorded at 30 minute intervals throughout the day of recording and at 60 minute intervals during sleep. ^ RESULTS: No significant associations were found between weight status and mean 24-hr systolic blood pressure (SBP) or mean arterial pressure (MAP). A significant and inverse association between weight status and mean 24-hr diastolic blood pressure (DBP) was revealed. Cardiorespiratory fitness was significantly and inversely associated with mean 24-hr ABP. High fitness adolescents had significantly lower mean 24-hr SPB, DBP, and MAP measurements than low fitness adolescents. Compared to low fitness adolescents, high fitness adolescents had 1.90 mmHg, 1.16 mmHg, and 1.68 mmHg lower mean 24-hr SBP, DBP, and MAP, respectively. Additionally, high fitness appeared to afford protection from higher mean 24-hr SBP and MAP, irrespective of weight status. Among normal weight adolescents, low fitness resulted in higher mean 24-hr SBP and MAP, compared to their fit counterparts. Among adolescents categorized as high fitness, increasing weight status did not appear to result in higher mean 24-hr SBP or MAP. Cardiorespiratory fitness, rather than weight status, appeared to be a more dominant predictor of mean 24-hr SBP and MAP. ^ CONCLUSIONS: To our knowledge, this research is the first study to investigate the independent and combined contributions of cardiorespiratory fitness and weight status on 24-hr ABP, all objectively measured. The results of this study may potentially guide and inform future research. It appears that early cardiovascular disease (CVD) prevention should focus on improving cardiorespiratory fitness levels among all adolescents, particularly those adolescents least fit, regardless of their weight status, while obesity prevention efforts continue.^

A cross-sectional analysis of physical activity and obesity in inner city Houston Texas Mexican American youth

Obesity prevalence among children and adolescents is rising. It is one of the most attributable causes of hospitalization and death. Overweight and obese children are more likely to suffer from associated conditions such as hypertension, dyslipidemia, chronic inflammation, increased blood clotting tendency, endothelial dysfunction, hyperinsulinemia, and asthma. These children and adolescents are also more likely to be overweight and obese in adulthood. Interestingly, rates of obesity and overweight are not evenly distributed across racial and ethnic groups. Mexican American youth have higher rates of obesity and are at higher risk of becoming obese than non-Hispanic black and non-Hispanic white children. ^ Methods. This cross-sectional study describes the association between rates of obesity and physical activity in a sample of 1313 inner-city Mexican American children and adolescents (5-19 years of age) in Houston, Texas. This study is important because it will contribute to our understanding of childhood and adolescent obesity in this at-risk population. ^ Data from the Mexican American Feasibility Cohort using the Mano a Mano questionnaire are used to describe this population's status of obesity and physical activity. An initial sample taken from 5000 households in inner city Houston Texas was used as the baseline for this prospective cohort. The questionnaire was given in person to the participants to complete (or to parents for younger children) at a home visit by two specially trained bilingual interviewers. Analysis comprised prevalence estimates of obesity represented as percentile rank (<85%= normal weight, >85%= at risk, >95%= obese) by age and gender. The association between light, moderate, strenuous activity, and obesity was also examined using linear regression. ^ Results. Overall, 46% of this Mexican American Feasibility cohort is overweight or obese. The prevalence for children in the 6-11 age range (53.2%) was significantly greater than that reported from NHANES, 1999–2002 data (39.4%). Although the percentage of overweight and obese among the 12-19 year olds was greater than that reported in NHANES (38.5% versus 38.6%) this difference was not statistically significant. ^ A significant association between BMI and sit time and moderate physical activity (both p < 0.05) found in this sample. For males, this association was significant for moderate physical activity (p < 0.01). For the females, this association was significant for BMI and sit time (p < 0.05). These results need to be interpreted in the light of design and measurement limitations. ^ Conclusion. This study supports observations that the inner city Houston Texas Mexican American child and adolescent population is more overweight and obese than nationally reported figures, and that there are positive relationships between BMI, activity levels, and sit time in this population. This study supports the need for public health initiatives within the Houston Hispanic community. ^

A meta-analysis: Obesity and colorectal cancer screening

Of cancer death, colorectal cancer death ranks second in the United States. Obesity is an important risk factor for colorectal cancer (1). Early detection of colorectal cancer when it is localized can effectively reduce mortality of colorectal cancer and increase survival time of patients if they are treated. Also, previous studies showed that obese women were more likely to delay breast cancer screening and cervical cancer screening than normal weight women (2-5). However, results from prior studies demonstrating the relationship between obesity and colorectal cancer screening are not consistent. This research was done to conduct a meta-analysis of previous cross-sectional studies selected from the Medline database and to evaluate the association between obesity and colorectal cancer screening. While the odds ratio was not statistically different from one, the results from this meta-analysis under the random effects model showed that obese people are slightly less likely to have colorectal cancer screening compared to normal weight individuals (OR,0.93;95% CI 0.75-1.15). This meta-analysis was particularly sensitive to one individual study (6) and the effect of obesity on colorectal cancer screening was statistically significant (OR, 0.87; 95% CI, 0.81-0.92) after removing Heo's study. Further systematic studies focused on whether the effect of obesity on colorectal cancer screening is limited to women only are suggested. ^

Contraceptive use in women by body mass index categories

The prevalence of obesity has increased sharply in the United States since the mid 1970's. Obese women who become pregnant are at increased risk of pregnancy complications for both mother and fetus. This study assessed whether women in higher body mass index (BMI) categories engage in the preventive behaviors of contraception more frequently than normal weight women. It also evaluated the type of contraception used by both obese and normal weight women. The study used cross-sectional data from 7 states participating in the Family Planning Module of the 2006 Behavioral Risk Factor Surveillance System (BRFSS). The Behavioral Risk Factor Surveillance System survey is an annual random digit dialed telephone survey of the non-institutionalized civilian population aged 18 years and older. The Family Planning Module was administered by Arizona, Kentucky, Minnesota, Missouri, Montana, Oregon, and Wisconsin. Of the 4,757 women who participated in the Family Planning Module, 2,244 (53.2%) were normal weight, 1,202 (25.6%) were overweight, and 1,072 (21.2%) were obese. The majority of these women 4,115 (86.2%) reported using some type of contraception to prevent pregnancy. Six hundred forty two women (13.8%) stated they did not use any type of contraception to prevent pregnancy. Within body mass index categories, 14% of normal weight women, 13% of overweight women, and 13.4% of obese women did not use any type of contraception. Neither the bivariate analysis nor the logistic regressions found body mass index categories to be statistically associated with contraceptive use. The relationship between body mass index categories and contraceptive method was found to be statistically significant. The predictive probability graph found that women at all levels of BMI have a lower probability of using barrier contraception methods as compared to procedural and hormonal methods. Hormonal contraception methods have the highest probability of use for women with a BMI of 15 to 25. In contrast, the probability of using procedural contraception methods is relatively flat and less than hormonal methods for BMI between 15 and 25. However, the probability of using procedural contraception increases dramatically with a BMI greater than 25. At a BMI greater than 42, women have a greater than 50% probability of using procedural contraception. Although a relationship between body mass index and contraception use was not found, contraception method was found to be associated with body mass index. The reasons why normal weight women prefer hormonal contraception while overweight/obese women are more likely to use procedural methods needs to be explored. By understanding the relationship between obesity and contraception, we can hopefully decrease unintended pregnancies and overall improve pregnancy related health outcomes. To determine if relationships between contraception use/type and body mass index exist, further research needs to be conducted on a national level. ^

The prevalence, health risks, and consequences of asthma among adult residents in Texas

Based on asthma prevalence data collected from the 2000 BRFSS survey, approximately 14.7 million U.S. adults had current asthma, accounting for 7.2% of the total U.S. population. In Texas alone, state data extrapolated from the 1999-2003 Texas BRFSS suggested that approximately 1 million Texas adults were reporting current asthma and approximately 11% of the adult population has been diagnosed with the illness during their lifetime. From a public health perspective, the disease is manageable. Comprehensive state-specific asthma surveillance data are necessary to identify disparities in asthma prevalence and asthma-control characteristics among subpopulations and to develop targeted public health interventions. The purpose of this study was to determine the relative importance of various risk factors of asthma and to examine the impact of asthma on health-related quality of life among adult residents of Texas. ^ The study employed a cross-sectional study of respondents in Texas. The study extracted all the variables related to asthma along with their associated demographic, socioeconomic, and quality of life variables from the 2007 BRFSS data for 17,248 adult residents of Texas aged 18 and older. Chi-square test and logistic regression using SPSS were used in various data analyses on weighted data, adjusting for the complex sample design of the BRFSS data. All chi-square analyses were carried out using SPSS's CSTABULATE command. In addition, logistic regression models were fitted using SPSS's CSLOGISTIC command. ^ Risks factors significantly associated with reporting current asthma included BMI, race/ethnicity, gender, and income. Holding all other variables constant, obese adults were almost twice as likely to report current asthma as those adults who were normal weight (odds ratio [OR], 1.78; 95% confidence interval [CI], 1.25 to 2.53). Other non-Hispanic adults were significantly more likely to report current asthma than non-Hispanic Whites (OR, 2.43; 95% CI, 1.38 to 4.25), while Hispanics were significantly less likely to report current asthma than non-Hispanic Whites (OR, 0.38; 95% CI, 0.25 to 0.60), after controlling for all other variables. After adjusting for all other variables, adult females were almost twice as likely to report current asthma as males (OR, 1.97; 95% CI, 1.49 to 2.60). Adults with household income of less than $15,000 were almost twice as likely to report current asthma as those persons with an annual household income of $50,000 or more (OR, 1.98; 95% CI, 1.33 to 2.94). In regards to the association between asthma and health-related quality of life, after adjusting for age, race/ethnicity, gender, tobacco use, body mass index (BMI), exercise, education, and income, adults with current asthma compared to those without asthma were more likely to report having more than 15 days of unhealthy physical health (OR, 1.84; 95% CI, 1.29 to 2.60). ^ Overall, the findings of this study provide insight and valuable information into the populations in Texas most adversely affected by asthma and health-related consequences of the disease condition. Further research could build on the findings of this study by replicating this study as closely as possible in other asthma settings, and look at the relationship for hospitalization rates, asthma severity, and mortality.^

A formative evaluation of the American Diabetes Association's Choosing Health and Sensible Exercise childhood obesity intervention

Background. The increasing prevalence of overweight among youth in the United States, and the parallel rise in related medical comorbidities has led to a growing need for efficient weight-management interventions. Purpose. The aim of this study was to evaluate the effects of the Choosing Health and Sensible Exercise (C.H.A.S.E.) childhood obesity prevention program on Body Mass Index (BMI), physical activity and dietary behaviors. Methods. This study utilized de-identified data collected during the fall 2006 session of the C.H.A.S.E. program. A total of 65 students at Woodview Elementary School and Deepwater Elementary School participated in this intervention. The C.H.A.S.E. program is a 10-week obesity prevention program that focuses on nutrition and physical activity education. Collection of height and weight data, and a health behavior survey was conducted during the first and last week of the intervention. Paired t-tests were used to determine statistically significant differences between pre- and post-intervention measurements. One-way analysis of variance was used to adjust for potential confounders, such as gender, age, BMI category ("normal weight", "at risk overweight", or "overweight"), and self-reported weight loss goals. Data were analyzed using STATA, v. 9.2. Results. A significant decrease in mean BMI (p< 0.05) was found after the 10-week intervention. While the results were statistically significant for the group as a whole, changes in BMI were not significant when stratified by age, sex, or ethnicity. The mean overall scores for the behavior survey did not change significantly pre- and post-intervention; however, significant differences were found in the dietary intention scale, indicating that students were more likely to intend to make healthier food choices (p<0.05). No statistically significant decreases in BMI were found when stratified for baseline BMI-for-age percentiles or baseline weight loss efforts (p>0.05). Conclusion. The results of this evaluation provide information that will be useful in planning and implementing an effective childhood obesity intervention in the future. Changes in the self-reported dietary intentions and BMI show that the C.H.A.S.E. program is capable of modifying food choice selection and decreasing BMI. Results from the behavior questionnaire indicate that students in the intervention program were making changes in a positive direction. Future implementation of the C.H.A.S.E. program, as well as other childhood obesity interventions, may want to consider incorporating additional strategies to increase knowledge and other behavioral constructs associated with decreased BMI. In addition, obesity prevention programs may want to increase parental involvement and increase the dose or intensity of the intervention. ^

The relationship between body image and physical activity in African American women

High rates of overweight and obesity in African American women have been attributed, in part, to poor health habits, such as physical inactivity, and cultural influences on body image perceptions. The purpose of this study was to determine the relationship among body mass index (BMI=kg/m2), body image perception (perceived and desired) and physical activity, both self-reported and objectively measured. Anthropometric measures of BMI and Pulvers' culturally relevant body image, physical activity and demographic data were collected from 249 African American women in Houston. Women ( M = 44.8 yrs, SD = 9.5) were educated (53% college graduates) and were overweight (M = 35.0 kg/m2, SD = 9.2). Less than half of women perceived their weight correctly regardless of their actual weight (p < 0.001). Nearly three-fourths (73.9%) of women who were normal weight desired to be obese, and only 39.4% of women desired to be normal weight, regardless of actual or perceived weight. Women in all weight classes (normal, overweight and obese) varied in objective measures of physical activity (F(2,112) = 4.424, p = .014). Regression analyses showed objectively measured physical activity was significantly associated with BMI ( Beta = -2.45, p < .01) and self-reported walking was significantly associated with perceived BMI (Beta = -.156, p = .017). Results suggest African American women who are smaller want to be larger and African American women who are larger want to be smaller, revealing dichotomous distortion in body images. Low rates of physical activity may be a factor. Research is needed to increase physical activity levels in African American women, leading to improved satisfaction with normal weight as desirable for health and beauty. Supported by NCI (NIH) 1R01CA109403. ^

THE USE OF ARM CIRCUMFERENCE FOR SIMPLIFIED SCREENING FOR MALNUTRITION BY MINIMALLY TRAINED HEALTH WORKERS

Because of its simplicity and low cost, arm circumference (AC) is being used increasingly in screening for protein energy malnutrition among pre-school children in many parts of the developing world, especially where minimally trained health workers are employed. The objectives of this study were as follows: (1) To determine the relationship of the AC measure with weight for age and weight for height in the detection of malnutrition among pre-school children in a Guatemalan Indian village. (2) To determine the performance of minimally trained promoters under field conditions in measuring AC, weight and height. (3) To describe the practical aspects of taking AC measures versus weight, age and height.^ The study was conducted in San Pablo La Laguna, one of four villages situated on the shores of Lake Atitlan, Guatemala, in which a program of simplified medical care was implemented by the Institute for Nutrition for Central America and Panama (INCAP). Weight, height, AC and age data were collected for 144 chronically malnourished children. The measurements obtained by the trained investigator under the controlled conditions of the health post were correlated against one another and AC was found to have a correlation with weight for age of 0.7127 and with weight for height of 0.7911, both well within the 0.65 to 0.80 range reported in the literature. False positive and false negative analysis showed that AC was more sensitive when compared with weight for height than with weight for age. This was fortunate since, especially in areas with widespread chronic malnutrition, weight for height detects those acute cases in immediate danger of complicating illness or death. Moreover, most of the cases identified as malnourished by AC, but not by weight for height (false positives), were either young or very stunted which made their selection by AC better than weight for height. The large number of cases detected by weight for age, but not by AC (false negative rate--40%) were, however, mostly beyond the critical age period and had normal weight for heights.^ The performance of AC, weight for height and weight for age under field conditions in the hands of minimally trained health workers was also analyzed by correlating these measurements against the same criterion measurements taken under ideally controlled conditions of the health post. AC had the highest correlation with itself indicating that it deteriorated the least in the move to the field. Moreover, there was a high correlation between AC in the field and criterion weight for height (0.7509); this correlation was almost as high as that for field weight for height versus the same measure in the health post (0.7588). The implication is that field errors are so great for the compounded weight for height variable that, in the field, AC is about as good a predictor of the ideal weight for height measure.^ Minimally trained health workers made more errors than the investigator as exemplified by their lower intra-observer correlation coefficients. They consistently measured larger than the investigator for all measures. Also there was a great deal of variability between these minimally trained workers indicating that careful training and followup is necessary for the success of the AC measure.^ AC has many practical advantages compared to the other anthropometric tools. It does not require age data, which are often unreliable in these settings, and does not require sophisticated subtraction and two dimensional table-handling skills that weight for age and weight for height require. The measure is also more easily applied with less disturbance to the child and the community. The AC tape is cheap and not easily damaged or jarred out of calibration while being transported in rugged settings, as is often the case with weight scales. Moreover, it can be kept in a health worker's pocket at all times for continual use in a widespread range of settings. ^

Influence of family meals on obesity and dietary behaviors among adolescents in India

The study objectives were to (i) Describe the frequency and priority of family meals, (ii) Compare the family mealtime environment by gender and SES, (iii) Examine the association between family meals and weight status among adolescents living in New Delhi, India, (iv) Examine the association between family meals and eating patterns (healthy/unhealthy) among adolescent boys and girls living in New Delhi, India. Survey and anthropometric data were collected from 8th and 10th grade students (n=1818) from four Government (public) schools and four private schools who participated in the HRIDAY study. Chi-square tests were used to evaluate if the distributions of outcomes and exposure varied by gender and SES groups. Logistic regression models were used to obtain the association of weight status (underweight / normal weight Vs overweight / obese) with frequency of family meals as the main exposure. Overall the prevalence of obesity was more among the mid- high SES group and in boys. Over half of the participants had 7 or more family meals in the past week. There was no statistically significant association seen between family meals and weight status. Majority of the participants believed that eating healthy food and maintaining a healthy weight was important and eating at least one family meal was important. Majority of the participants who ate more than 3 or more family meals eat healthy food and also ate fast food. Intervention strategies should focus on the high risk group. Private schools are appropriate settings for interventions. Eating with families should be encouraged and future research should examine family meal patterns.^

Bullied status and physical activity in Texas youths

Data from the 2009–2011 School Physical Activity and Nutrition (SPAN) project were analyzed to examine the association between bullied status at school during the past six months and engaging in five or more days of physical activity during the past seven days in a population of 8th and 11th grade Texas youths after stratifying by gender. As a secondary aim, this study also examined the association between weight status and the prevalence of bullied status at school. The final sample size for this study, after excluding missing data, consisted of 6,246 8th and 11th grade youths (girls, n= 3,237; boys, n=3,009) representing a total of 518,838 youths from 8th and 11th grade. Results from the multiple logistic regression adjusting for weight status, grade, and ethnicity, indicate that girls with a bullied status of at least two or three times per month had significantly lower odds of engaging in five or more days of physical activity during the past seven days than girls who were never bullied at school (ORadj=0.62; 95% CI, 0.40, 0.96). Conversely, girls who reported a bullied status of at least once per week were significantly more likely to engage in five or more days of physical activity during the past seven days compared to girls who were never bullied at school (ORadj=3.44; 95% CI, 1.56, 7.63). No significant associations between bullied status and engaging in five or more days of physical activity during the past seven days were found for boys. Bullied status differed significantly across weight status for 8th grade girls (χ2(6)=63.7, p<.05) and 11th grade boys (χ2(6) =94.93, p<.05), with overweight and obese youths reporting a higher prevalence of being bullied once or twice, at least two or three times per month, and at least once per week than their normal weight peers. Our finding that girls with bullied status of at least once per week were more likely to engage in five or more days of physical activity than girls who were never bullied warrants future qualitative research to identify potential explanations for such results. Future research on relational and weight-based bullying is also needed and may help explain the inconsistent findings between bullied status and engaging in physical activity in girls.^

Effects of overweight and obesity on economic outcomes among U.S. adults with kidney disease

Background. Kidney disease is a growing public health phenomenon in the U.S. and in the world. Downstream interventions, dialysis and renal transplants covered by Medicare's renal disease entitlement policy in those who are 65 years and over have been expensive treatments that have been not foolproof. The shortage of kidney donors in the U.S. has grown in the last two decades. Therefore study of upstream events in kidney disease development and progression is justified to prevent the rising prevalence of kidney disease. Previous studies have documented the biological route by which obesity can progress and accelerate kidney disease, but health services literature on quantifying the effects of overweight and obesity on economic outcomes in the context of renal disease were lacking. Objectives . The specific aims of this study were (1) to determine the likelihood of overweight and obesity in renal disease and in three specific adult renal disease sub-populations, hypertensive, diabetic and both hypertensive and diabetic (2) to determine the incremental health service use and spending in overweight and obese renal disease populations and (3) to determine who financed the cost of healthcare for renal disease in overweight and obese adult populations less than 65 years of age. Methods. This study was a retrospective cross-sectional study of renal disease cases pooled for years 2002 to 2009 from the Medical Expenditure Panel Survey. The likelihood of overweight and obesity was estimated using chi-square test. Negative binomial regression and generalized gamma model with log link were used to estimate healthcare utilization and healthcare expenditures for six health event categories. Payments by self/family, public and private insurance were described for overweight and obese kidney disease sub-populations. Results. The likelihood of overweight and obesity was 0.29 and 0.46 among renal disease and obesity was common in hypertensive and diabetic renal disease population. Among obese renal disease population, negative binomial regression estimates of healthcare utilization per person per year as compared to normal weight renal disease persons were significant for office-based provider visits and agency home health visits respectively (p=0.001; p=0.005). Among overweight kidney disease population health service use was significant for inpatient hospital discharges (p=0.027). Over years 2002 to 2009, overweight and obese renal disease sub-populations had 53% and 63% higher inpatient facility and doctor expenditures as compared to normal weight renal disease population and these result were statistically significant (p=0.007; p=0.026). Overweigh renal disease population had significant total expenses per person per year for office-based and outpatient associated care. Overweight and obese renal disease persons paid less from out-of-pocket overall compared to normal weight renal disease population. Medicare and Medicaid had the highest mean annual payments for obese renal disease persons, while mean annual payments per year were highest for private insurance among normal weight renal disease population. Conclusion. Overweight and obesity were common in those with acute and chronic kidney disease and resulted in higher healthcare spending and increased utilization of office-based providers, hospital inpatient department and agency home healthcare. Healthcare for overweight and obese renal disease persons younger than 65 years of age was financed more by private and public insurance and less by out of pocket payments. With the increasing epidemic of obesity in the U.S. and the aging of the baby boomer population, the findings of the present study have implications for public health and for greater dissemination of healthcare resources to prevent, manage and delay the onset of overweight and obesity that can progress and accelerate the course of the kidney disease.^

Specific, Reversible Cytostatic Protection of Normal Cells Against Negative Effects of Chemotherapy

Chemotherapy is a common and effective method to treat many forms of cancer. However, treatment of cancer with chemotherapy has severe side effects which often limit the doses of therapy administered. Because some cancer chemotherapeutics target proliferating cells and tissues, all dividing cells, whether normal or tumor, are affected. Cell culture studies have demonstrated that UCN-01 is able to reversibly and selectively arrest normal dividing cells; tumor cells lines do not undergo this temporary arrest. Following UCN-01 treatment, normal cells displayed a 50-fold increase in IC50 for camptothecin; tumor cells showed no such increased tolerance. We have examined the response of the proliferating tissues of the mouse to UCN- 01 treatment, using the small bowel epithelium as a model system. Our results indicate that UCN-01 treatment can cause a cell cycle arrest in the gut epithelium, beginning 24 hours following UCN-01 administration, with cell proliferation remaining suppressed for one week. Two weeks post-UCN-01 treatment the rate of proliferation returns to normal levels. 5-FU administered during this period demonstrates that UCN-01 is able to provide protection to normal cells of the mouse within a narrow window of efficacy, from three to five days post-UCN-01. UCN-01 pretreated mice displayed improved survival, weight status and blood markers following 5-FU compared to control mice, indicating that UCN-01 can protect normal dividing tissues. The mechanism by which UCN-01 arrests normal cells in vivo was also examined. We have demonstrated that UCN-01 treatment in mice causes an increase in the G1 phase cell cycle proteins cdk4 and cyclin D, as well as the inhibitor p27. Phosphorylated Rb was also elevated in the arrested cells. These results are a departure from cell culture studies, in which inhibition of G1 phase cyclin dependent kinases led to hyposphosphorylation of Rb. Future investigation will be required to understand the mechanism of UCN-01 action. This is important information, especially for identification of alternate compounds which could provide the protection afforded by UCN-01.

THE LONG-TERM GROWTH OF NORMAL HUMAN B CELLS

The feasibility of establishment of continuously proliferating growth factor-dependent human B lymphocytes was investigated. Normal B lymphocytes prepared from peripheral venous blood were stimulated with a variety of known polyclonal B cell activators, in the continuous presence of various cytokine preparations. Continuously proliferating growth factor-dependent B cell populations were obtained from cultures activated with either insoluble anti-IgM ((mu)-chain specific), soluble anti-IgM, heat-killed Staphylococcus aureus Cowen I (SAC), or dextran sulphate (DxS), in the continuous presence of exogenously added growth factor preparations containing either IL-1, IL-2 and BCGF, or BCGF alone. Although growth factor-dependent B cell lines were obtained via all three methods of activation, the correlation of mode of activation and growth factor preparation proved to be critical. B cell lines could not be established with anti-(mu) activation in the presence of only BCGF; however, B cell lines were successfully obtained with SAC or DxS activation from those cultures continuously replenished with only BCGF. These cultured B lymphocyte populations were routinely maintained in logarithmic-phase growth in the presence of exogenously added growth factor, and exhibited a population doubling time of approximately 36 hours. They were shown to specifically absorb BCGF, suggesting the presence of membrane receptors for it. Also, these cultured B cells have been utilized for the development of a microassay for the assessment of a M(,r) 12,000-14,000 B cell growth factor activity that is accurate, sensitive, and precise. The pronounced sensitivity of this bioassay beyond that of the conventional peripheral blood B cell assay has aided in the purification to homogeneity of natural product extracellular BCGF (EC-BCGF), and in the determination of the nucleotide sequence for a gene coding for a protein exhibiting BCGF activity. Additionally, these B cell lines specifically absorb, and proliferate in the presence of, an affinity-purified M(,r) 60,000 trypsin-sensitive intracellular protein derived from freshly isolated human T lymphocytes, providing evidence for a putative intracellular precursor of EC-BCGF, or a novel high molecular weight BCGF species. ^

POU domain transcription factor Brn3b is critical for the normal development and survival of retinal ganglion cells

The POU domain transcription factor Brn3b/POU4F2 plays a critical role regulating gene expression in mouse retinal ganglion cells (RGCs). Previous investigations have shown that Brn3b is not required for initial cell fate specification or migration; however, it is essential for normal RGC differentiation. In contrast to wild type axons, the mutant neurites were phenotypically different: shorter, rougher, disorganized, and poorly fasciculated. Wild type axons stained intensely with axon specific marker tau-1, while mutant projections were weakly stained and the mutant projections showed strong labeling with dendrite specific marker MAP2. Brn-3b mutant axonal projections contained more microtubules and fewer neurofilaments, a dendritic characteristic, than the wild type. The mutant neurites also exhibited significantly weaker staining of neurofilament low-molecular-weight (NF-L) in the axon when compared to the wild type, and NF-L accumulation in the neuron cell body. The absence of Brn-3b results in an inability to form normal axons and enhanced apoptosis in RGCs, suggesting that Brn-3b may control a set of genes involved in axon formation. ^ Brn3b contains several distinct sequence motifs: a glycine/serine rich region, two histidine rich regions, and a fifteen amino acid conserved sequence shared by all Brn3 family members in the N-terminus and a POU specific and POU homeodomain in the C-terminus. Brn3b activates a Luciferase reporter over 25 fold in cell culture when binding to native brn3 binding sites upstream of a minimal promoter. When fused to the Gal4 DNA Binding domain (DBD) and driven by either a strong (CMV) or weaker (pAHD) promoter, the N-terminal of Brn3b is capable of similar activation when binding to Gal4 UAS sites, indicating a presumptive activator of transcription. Both full length Brn3b or the C-terminus fused to the Gal4DBD and driven by pCMV repressed a Luciferase reporter downstream of UAS binding sites. Lower levels of expression of the fusion protein driven by pADH resulted in an alleviation of repression. This repression appears to be a limitation of this system of transcriptional analysis and a potential pitfall in conventional pCMV based transfection assays. ^