Osteopontin (OPN) and neoplastic disease: Circulating levels and tissue distribution

OPN is a secreted phosphate containing protein which is expressed by osteoblasts and a variety of other cells in vivo. Data from in vitro studies has accumulated which relates OPN to cellular transformation. We hypothesize that OPN expression is associated with neoplastic disease in humans as suggested by cell culture models. The overall objective of the current study was to determine the tissue distribution of OPN in human malignancy and to determine whether or not a correlation exists between OPN serum levels and malignancy. At the inception of this project, no study had been made demonstrating the relevance of OPN expression with naturally occurring neoplastic disease in humans. To date, few studies have reported OPN distribution in human neoplasia and are limited by either the number of specimens analyzed or the technique used in analysis. In this dissertation study, OPN was purified from human milk and $\alpha$-OPN antiserum developed and characterized. Following antibody development, the distribution and prevalence of OPN in human oral squamous cell carcinoma and human prostate carcinoma was evaluated using immunohistochemical localization. OPN immunolocalization was found in a high percentage of oral epithelial dysplasia and oral squamous cell carcinoma in humans. One oral squamous cell carcinoma cells line, UMSCC-1, was found to express OPN mRNA using Northern blotting. OPN localized to a high percentage of primary prostate adenocarcinomas. OPN localized to 52% of androgen dependent cases and 100% of androgen independent cases. Androgen dependent cell lines such as LNCap and NbE showed minimal OPN mRNA expression while the androgen independent lines C4-2 and PC3 produced ample OPN mRNA. An OPN sandwich assay was developed and used to determine the serum level of OPN in normal males, patients with BPH (benign prostate hypertrophy), and patients with prostate carcinoma. No statistically significant difference was found in OPN serum levels among the three groups. However, a trend of increasing OPN in the serum was noted in patients with BPH and prostate cancer. ^

A practice-based culminating experience with Texas Children's Hospital: A hospital's journey to baby-friendly status

Breastfeeding and the use of human milk are widely accepted as the most complete form of nutrition for infants. Breastfeeding is shown to be associated with many positive health outcomes for both infants and mothers. Healthy People 2000 goals to increase breastfeeding rates in the early postpartum period to 75% fell short, with only 64% of mothers meeting this objective. Lack of support from healthcare providers, and unsupportive hospital policies and practices are noted as barriers to the initiation and duration of breastfeeding. The purpose of this study was to evaluate implementation of the BFHI Ten Steps to Successful Breastfeeding at Texas Children's Hospital. ^ The Baby-Friendly Hospital Initiative (BFHI) was developed in 1991 by the World Health Organization and the United Nations Children's Fund (UNICEF) to ensure that healthcare facilities offering maternity services adhere to the Ten Steps of Successful Breastfeeding and the International Code of Marketing of Breast-Milk Substitutes, and create legislation to protect the rights of breastfeeding women. The instrument used in this study was the BFHI 100 Assessment Tool created by Dr. Laura Haiek, Director of Public Health in Monteregie, Quebec, and her staff at Health and Social Services Agency of Quebec. The BFHI 100 tool utilizes 100 different indicators of compliance with BFHI through questionnaires administered to staff and administrators, pregnant and postpartum mothers, and an observer. ^ The study concluded that although there is much room for improvement in educating breastfeeding mothers, overall, the mothers interviewed were satisfied with their level of care in regards to breastfeeding support. Areas of improvement include staff training, as some nursing staff admitted to relying on the lactation consultants to provide most of the breastfeeding education for mothers. Only a small percentage of mothers interviewed reported that their baby “roomed-in” on average of 22 hours per day during their hospital stay. Staff encouragement of the rooming-in practice will help to increase the proportion of mothers who allow their babies to room-in. The current breastfeeding policy will also need to be revised and strengthened to be compliant with the Ten Steps. Ideally, Baby-Friendly practices will become the norm after staff are trained and policy revisions are made. Staff training and acceptance of breastfeeding as optimal nutrition for infants are the most critical factors that will ultimately drive change for the organization. ^

Polybrominated diphenyl ethers: Potential human exposure through household dust and dryer lint

This MPH thesis consists of (1) literature review of the relatively new synthetic persistent organic pollutants (POP), polybrominated diphenyl ethers (PBDEs), a type of flame retardant posing a potential public health hazard, (2) Presentation of data on PBDE levels in dryer lint from Dallas, TX and Hamburg, Germany. ^ PBDEs are used as additive fire retardants in plastics, polyurethane foam and electronic equipment to reduce flammability and thus save life and property. PBDEs have been widely used beginning in the 1970s. They resemble polychlorinated biphenyls (PCBs) in structure and toxicity. PBDEs are found in environmental sediments, sludges, and wildlife and even in human blood, milk and tissues. ^ PBDEs, due to their lipophilicity, accumulate in fat and other tissues and biomagnify up the food chain, with increasing concentrations. Animal studies have suggested potential health effects including thyroid disruption, permanent learning and memory impairment, fetal malformations, developmental neurotoxicity and, at high doses, possibly cancer. ^ PBDE levels are increasing in blood and breast milk in North America, but PBDEs intake unlike PCBs appears to be not primarily through food; food PBDE levels in the U.S. are not markedly higher than in Europe yet U.S. human blood and milk levels are much higher. For this reason various exposure pathways including PBDE contaminated dust and air have been studied to better characterize routes of PBDE intake into humans. ^ The scientific literature on PBDE levels in household dust reports higher PBDE concentration in dust than that found in dryer lint; levels in the U.S are elevated compared to other countries with congeners such as BDE 47, 99, 100 and 209 predominating. The United Kingdom has elevated BDE 209 due to high usage of Deca commercial mixture. These studies suggest that indoor PBDE contamination through household dust could be a potential source of PBDE exposure and body burden especially in young children. ^ PBDE levels in dryer lint from U.S ranged from 321 to 3073 ng/g (Mean: 1138 ng/g, Median: 803 ng/g) and from Germany were from 330 to 2069 ng/g (Median: 71ng/g, Mean: 361 ng/g). High median levels in U.S samples indicate contamination of lint with PBDEs although the source of the PBDEs in lint may be from dryer electrical components or air deposition onto clothes, lint may be one source of PBDE exposure to humans. ^