Citations

Abstract Subclinical variation in immune response may be a risk factor for non-Hodgkin lymphoma (NHL). Endotoxin is a substance located in the cell wall of gram-negative bacteria that elicits a strong innate and inflammatory immune response. It is present in large amounts in animal and human fecal material, other organic material, and cigarette smoke. We hypothesized that higher endotoxin exposure might be a risk factor for NHL because of its effect on B-cell activation. Using a population based, multi-center (Detroit, Iowa, Los Angeles and Seattle) case-control study, we evaluated the association between endotoxin levels in carpet dust and NHL risk. During an in-person interview, we collected used vacuum cleaner bags from participants who had used their vacuum within the past year and had owned at least half of their carpets or rugs for 5 years or more. Dust samples were analyzed using the kinetic chromogenic Limulus amebocyte lysate assay in the Pulmonary Toxicology Facility, University of Iowa. Endotoxin measurements from 629 cases and 467 controls were log-transformed and evaluated as both continuous and categorical variables. In order to examine a possible threshold effect, endotoxin levels among controls were categorized into tertiles, with the highest tertile further split into two equal groups based on a preliminary model search. Multivariable logistic regression was used to estimate the effect of endotoxin on NHL risk adjusted for sex, age, race, education, study center, and last change of vacuum bag. The highest category of household endotoxin level in dust was associated with a 35% significantly decreased risk of NHL relative to the lowest category (95% confidence interval [CI] = 0.44, 0.96). The effect was stronger for the diffuse large B-cell lymphoma (DLBCL) subtype (Odds Ratio [OR]= 0.49; 95% CI= 0.26,0.91). In conclusion, contrary to our initial hypothesis, our results suggest an inverse association between high levels of household endotoxin and NHL risk. Further studies are needed to validate this finding, ideally with endotoxin measurements prior to diagnosis. Possible mechanisms of action will be discussed. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5736.

Exosomes are small extracellular vesicles that are thought to participate in intercellular communication. Recent work from our laboratory suggests that, in normal and cystic liver, exosome-like vesicles accumulate in the lumen of intrahepatic bile ducts, presumably interacting with cholangiocyte cilia. However, direct evidence for exosome-ciliary interaction is limited and the physiological relevance of such interaction remains unknown. Thus, in this study, we tested the hypothesis that biliary exosomes are involved in intercellular communication by interacting with cholangiocyte cilia and inducing intracellular signaling and functional responses. Exosomes were isolated from rat bile by differential ultracentrifugation and characterized by scanning, transmission, and immunoelectron microscopy. The exosome-ciliary interaction and its effects on ERK1/2 signaling, expression of the microRNA, miR-15A, and cholangiocyte proliferation were studied on ciliated and deciliated cultured normal rat cholangiocytes. Our results show that bile contains vesicles identified as exosomes by their size, characteristic “saucer-shaped” morphology, and specific markers, CD63 and Tsg101. When NRCs were exposed to isolated biliary exosomes, the exosomes attached to cilia, inducing a decrease of the phosphorylated-to-total ERK1/2 ratio, an increase of miR-15A expression, and a decrease of cholangiocyte proliferation. All these effects of biliary exosomes were abolished by the pharmacological removal of cholangiocyte cilia. Our findings suggest that bile contains exosomes functioning as signaling nanovesicles and influencing intracellular regulatory mechanisms and cholangiocyte proliferation through interaction with primary cilia.

Background and Purpose— Telemedicine techniques can be used to address the rural–metropolitan disparity in acute stroke care. The Stroke Team Remote Evaluation Using a Digital Observation Camera (STRokE DOC) trial reported more accurate decision making for telemedicine consultations compared with telephone-only and that the California-based research network facilitated a high rate of thrombolysis use, improved data collection, low risk of complications, low technical complications, and favorable assessment times. The main objective of the STRokE DOC Arizona TIME (The Initial Mayo Clinic Experience) trial was to determine the feasibility of establishing, de novo, a single-hub, multirural spoke hospital telestroke research network across a large geographical area in Arizona by replicating the STRokE DOC protocol. Methods— Methods included prospective, single-hub, 2-spoke, randomized, blinded, controlled trial of a 2-way, site-independent, audiovisual telemedicine system designed for remote examination of adult patients with acute stroke versus telephone consultation to assess eligibility for treatment with intravenous thrombolysis. The primary outcome measure was whether the decision to give thrombolysis was correct. Secondary outcomes were rate of thrombolytic use, 90-day functional outcomes, incidence of intracerebral hemorrhages, and technical observations. Results— From December 2007 to October 2008, 54 patients were assessed, 27 of whom were randomized to each arm. Mean National Institutes of Health Stroke Scale score at presentation was 7.3 (SD 6.2) points. No consultations were aborted; however, technical problems (74%) were prevalent in the telemedicine arm. Overall, the correct treatment decision was established in 87% of the consultations. Both modalities, telephone (89% correct) and telemedicine (85% correct), performed well. Intravenous thrombolytic treatment was used in 30% of the telemedicine and telephone consultations. Good functional outcomes at 90 days were not significantly different. There were no statistically significant differences in mortality (4% in telemedicine and 11% in telephone) or rates of intracerebral hemorrhage (4% in telemedicine and 0% in telephone). Conclusions— It is feasible to extend the original STRokE DOC trial protocol to a new state and establish an operational single-hub, multispoke rural hospital telestroke research network in Arizona. The trial was not designed to have sufficient power to detect a difference between the 2 consultative modes: telemedicine and telephone-only. Whether by telemedicine or telephone consultative modalities, there were appropriate treatment decisions, high rates of thrombolysis use, improved data collection, low rates of intracerebral hemorrhage, and equally favorable time requirements. The learning curve was steep for the hub and spoke personnel of the new telestroke network, as reflected by frequent technical problems. Overall, the results support the effectiveness of highly organized and structured stroke telemedicine networks for extending expert stroke care into rural remote communities lacking sufficient neurological expertise.

It remains to be determined whether systemic insulin replacement normalizes synthesis rates of different plasma proteins and whether there are differential effects on various plasma proteins. We tested a hypothesis that insulin deprivation differentially affects individual plasma protein synthesis and that systemic insulin treatment may not normalize synthesis of all plasma proteins. We measured synthesis rates of 41 plasma proteins in seven each of type 1 diabetic (T1DM) and nondiabetic participants (ND) using [ ring-13C6]phenylalanine as a tracer. T1DM were studied while on chronic insulin treatment and during 8 h insulin deprivation. Insulin treatment normalized glucose levels, but plasma insulin levels were higher during insulin treatment than during insulin deprivation in T1DM and ND. Individual plasma proteins were purified by affinity chromatography and two-dimensional gel electrophoresis. Only 41 protein gel spots from over 300 were chosen based on their protein homogeneity. Insulin deprivation and hyperglycemia either significantly increased ( n = 12) or decreased ( n = 12) synthesis rates of 24 of 41 plasma proteins in T1DM compared with ND. Insulin treatment normalized synthesis rates of 13 of these 24 proteins, which were altered during insulin deprivation. However, insulin treatment significantly altered the synthesis of 14 additional proteins. In conclusion, acute insulin deprivation caused both a decrease and increase in synthesis rates of many plasma proteins with various functions. Moreover, chronic systemic insulin treatment not only did not normalize synthesis of all plasma proteins but also altered synthesis of several additional proteins that were unaltered during insulin deprivation.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited human renal disease and is caused by mutations in two genes, PKD1 (85%) and PKD2 (15%). Cyst epithelial cells are characterised by a complex cellular phenotype including changes in proliferation, apoptosis, basement membrane composition and apicobasal polarity. Since polycystin 1 (PC1), the PKD1 protein, has been located in the basolateral membrane of kidney epithelial cells, we hypothesised that it might have a key role in mediating or stabilising cell-cell interactions. In non-ciliated L929 cells, stable or transient surface expression of the PC1 extracellular domain was sufficient to confer an adhesive phenotype and stimulate junction formation. In MDCK cells, we found that PC1 was recruited to the lateral membranes coincident with E-cadherin within 30 minutes after a `calcium switch'. Recruitment of both proteins was significantly delayed when cells were treated with a PC1 blocking antibody raised to the PKD domains. Finally, PC1 and E-cadherin could be coimmunoprecipitated together from MDCK cells. We conclude that PC1 has a key role in initiating junction formation via initial homophilic interactions and facilitates junction assembly and the establishment of apicobasal polarity by E-cadherin recruitment.