Viability of limbal epithelium after anterior lamellar harvesting using a microkeratome

OBJECTIVE: To determine the viability in cold eye bank storage of different layers of central and limbal corneal epithelium, including the limbal basal stem cell population, on days 0, 3, 6, and 9 after harvest using a large diameter microkeratome system. METHODS: Twenty-two human whole globes not suitable for transplantation were obtained from an eye bank (San Diego Eye Bank, San Diego, California) and used for study. Large-diameter anterior corneal discs were prepared using a large diameter microkeratome and stained with calcein AM and an ethidium homodimer to differentiate live from dead cells, respectively. A laser confocal microscope and digital imaging were used to distinguish live (green) from dead (red) cells. Central and limbal epithelial regions were isolated and the middle and basal epithelial sections were cell counted by 3 independent observers. These sections were stored up to 9 days at 4 degrees C in an eye bank corneal storage medium. Differences were tested using nonparametric methods. MAIN OUTCOME MEASURES: The percentage of live cells in each of these epithelial layers was determined for up to 9 days in cold eye bank corneal storage medium. RESULTS: At all time points studied, the better protected basal epithelial layers displayed greater mean viability than the overlying middle epithelial layers. However, the difference was not statistically significant on all days. When comparing the basal epithelial viability of the limbal and central regions, after day 0 in 4 degrees C cold organ culture, the observed viability of the limbal basal epithelium, the purported location of the limbal epithelial stem cell region, was significantly greater than that of the central epithelium. On day 0, median limbal basal versus central basal epithelial viability were 100% (range, 71.7-100%) versus 98.4% (range, 88.9-100%) (P>0.05); on day 3, 100% (range, 64.3-100%) versus 63.4% (range, 13.6-95.5%) (P<0.0005); on day 6, 95.0% (range, 35.0-100%) versus 28.0% (range, 0-92.0%) (P<0.0005); and on day 9, 95.0% (range, 3.7-100%) versus 68.6% (range, 0-100%) (P<0.0005). CONCLUSIONS: After microkeratome harvesting, the limbal basal epithelium is significantly longer lived in cold eye bank storage than central basal epithelium and the middle layers of limbal and central epithelium. This longevity not only bodes well for organ storage of limbal grafts, but also confirms the hardiness of the stem cell region.     

Evidence supporting the inclusion of strains from each of the two co-circulating lineages of H3N8 equine influenza virus in vaccines

Two lineages of antigenically distinct equine influenza A H3N8 subtype viruses, American and European, co-circulate. Experiments were conducted in ponies to investigate the protection induced by vaccines containing virus from one lineage against challenge infection with homologous or heterologous virus. Regression analysis showed that vaccinated ponies with average pre-challenge single radial haemolysis (SRH) antibody levels (i.e. 45-190mm2) had a higher probability of becoming infected if they were vaccinated with virus heterologous to the challenge strain than if they were vaccinated with homologous virus. Field studies in Thoroughbred racehorses also showed that SRH antibody levels of >/= 150mm2 induced by vaccines containing a European lineage strain are protective against infection with a virus from the same lineage, but that the same or higher antibody levels may not be protective against an American lineage virus. In conclusion, vaccines should contain virus strains representative of both H3N8 subtype lineages to maximise protection against infection.     

Moving beyond disclosure: women's perspectives on barriers and motivators to seeking assistance for intimate partner violence

To investigate women's perceptions of motivators and barriers to seeking help or accessing intimate partner violence (IPV), services six focus groups were conducted in rural and urban settings in North Carolina between June and August of 2002. Coding and theme analysis were used to summarize themes among the 67 focus group participants.The majority of participants were African-American (87%). Participants reported three main categories of motivators: gaining knowledge; reaching an emotional or physical breaking point; and growing concern about children's safety. Participants reported six main categories of barriers: pressure not to talk about, or address IPV; failure to recognize events as IPV, or that IPV was wrong; self-doubt and low self-esteem; fear of losses; fear of perpetrator; or desire to protect the perpetrator. This study documents the difficulties that women face accessing or using services related to IPV. We need to address perceived barriers and better use the opportunity when women experience motivation to seek help and access services.     

Relation of family history of prostate cancer to perceived vulnerability and screening behavior

Men with a positive family history of prostate cancer are known to be at increased risk for the disease; however, relatively little is known about their risk perceptions or screening behavior. To address these issues, the current study examined the relationship of family history of prostate cancer to perceived vulnerability of developing prostate cancer and prostate cancer screening practices. Participants were 83 men with a positive family history of prostate cancer and 83 men with a negative family history of prostate cancer. As predicted, men with a positive family history reported greater (p< or =0.05) perceived vulnerability of developing prostate cancer and stronger intentions to undergo screening (p< or =0.05). They also reported greater past performance of prostate-specific antigen screening and were more likely to request information about prostate cancer (p< or =0.05). Additional analyses indicated that perceived vulnerability mediated the relation between family history and intentions to undergo prostate cancer screening. Findings confirm the increased likelihood of men with a positive family history to undergo prostate cancer screening and suggest that heightened concerns about developing the disease are an important motivating factor.     

Epidermal growth factor receptor as a target to improve treatment of lung cancer

Despite considerable efforts to reduce tobacco use, lung cancer remains the most common cancer in both men and women. Recent advances in radiation therapy and chemotherapy for lung cancer have yielded encouraging results, but survival in patients with locally advanced non-small-cell lung cancer (NSCLC) remains poor. As more and more molecular changes and their importance in malignant tissues continue to be characterized, approaches to target those aberrant pathways are being actively explored. The epidermal growth factor receptor (EGFR) is commonly overexpressed in NSCLC, particularly squamous cell carcinoma, and has been implicated in the development and progression of this disease, although a clear correlation with prognosis has not been established. Several different strategies have been developed to target and block the EGFR and its downstream effects, and some of them have been intensively studied in preclinical and clinical studies as a single-agent approach or in combination with radiation therapy or chemotherapy. In this article, we review the role of EGFR in lung cancer, as well as preclinical and clinical data on strategies to interfere with EGFR signaling alone or in combination with chemotherapy, radiation, or both.