Ontogenetic modification of the hypercapnic ventilatory response in the zebra finch.

We investigated the effect of exposure to CO2 during development on the adult ventilatory response to CO2 of zebra finches. Developing zebra finches were exposed to chronic hypercapnic respiratory environments as embryos, as nestlings or during both developmental periods. Their responsiveness to CO2 was then measured following a 125-135 day post-fledging deacclimation period. At a FICO2 of 0.06, mean ventilation of adult finches in the three groups was 74.8, 61.3 and 65.8%, respectively, of that of finches reared under normocapnic conditions. These data indicate that adult acute ventilatory responsiveness to CO2 in birds may be in part determined by CO2 exposure during early development and may help explain the observation that fossorial and semifossorial species of birds and mammals, that naturally encounter high CO2 conditions in their burrows, have a blunted hypercapnic ventilatory response.     

Damages caps in medical malpractice cases

This article reviews the empirical literature on the effects of damages caps and concludes that the better-designed studies show that damages caps reduce liability insurance premiums. The effects of damages caps on defensive medicine, physicians' location decisions, and the cost of health care to consumers are less clear. The only study of whether consumers benefit from lower health insurance premiums as a result of damages caps found no impact. Some state courts have based decisions declaring damages caps legislation unconstitutional on the lack of evidence of their effectiveness, thereby ignoring the findings of conflicting research studies or discounting their relevance. Although courts should be cautious in rejecting empirical evidence that caps are effective, legislators should consider whether they benefit consumers enough to justify limiting tort recoveries for those most seriously injured by malpractice.     

Growth factors and stromal support generate very efficient retroviral transduction of peripheral blood CD34+ cells from Gaucher patients

We have achieved high-efficiency gene transfer into nonmobilized peripheral blood (PB) CD34+ cells from patients with Gaucher's disease using a clinically acceptable retroviral supernatant transduction protocol. In our studies, bone marrow (BM) and PB CD34+ cells were transduced using a high titer (10(8) particles/mL) retroviral supernatant once a day for 4 consecutive days in the presence of interleukin-3 (IL-3), IL-6, and stem cell factor (SCF), with or without an irradiated allogeneic BM stromal layer. The growth factors alone resulted in 29% +/- 10% gene transfer of PB CD34+ clonogenic cells in contrast with 71% +/- 17% gene transfer efficiency using stroma with the growth factors; a 2.5-fold increase. The increase in gene transfer efficiency was less prominent when BM CD34+ cells were used (40% +/- 16% without and 57% +/- 8% with stroma, a 1.5-fold increase). The overall transduction efficiency of both PB and BM CD34+ cells was lower when the cells were transduced over a stromal cell layer without added growth factors. The combination of IL-3, IL-6, and SCF with stroma transduced 75% of primitive long-term culture initiating cells (PB LTC- ICs) in comparison with 34% of LTC-ICs when IL-3, IL-6, and SCF were used without stromal support. Using this clinically acceptable supernatant/cytokines/stroma transduction protocol, correction of the glucocerebrosidase (GC) deficiency in the progeny cells of PBLTC-ICs from Gaucher's-disease patients has been accomplished. Efficient transduction of the PB CD34+ cells using this transduction protocol may allow repeated delivery of "GC-corrected" hematopoietic stem and progenitor cells to Gaucher's-disease patients.     

Direct demonstration that autologous bone marrow transplantation for solid tumors can return a multiplicity of tumorigenic cells

Patients with solid tumors are increasingly being treated by autologous bone marrow transplantation (BMT). Although response rates appear to be increased, disease recurrence is the commonest cause of treatment failure. Whether relapse is entirely due to residual disease in the patient or arises also from infiltrating malignant cells contained in the autologous marrow transplant has not been resolved. If the latter explanation is correct, then purging would be required as part of the transplantation procedure. We used retrovirally mediated transfer of the neomycin-resistance gene to mark BM harvested from eight patients with neuroblastoma in clinical remission. The marked marrow cells were subsequently reinfused as part of an autologous BMT. At relapse, we sought the marker gene in malignant cell populations. Three patients have relapsed, and in each the marker gene was detected by phenotypic and genetic analyses of resurgent malignant cells at medullary and extramedullary sites. Analysis of neuroblast DNA for discrete marker gene integration sites suggested that at least 200 malignant cells, each capable of tumor formation, were introduced with the autologous marrow transplant and contributed to relapse. Thus, autologous BMTs administered to patients with this solid tumor may contain a multiplicity of malignant cells that subsequently contribute to relapse. The marker-gene technique we describe should permit evaluation of the mechanisms of relapse and the efficacy of purging in patients receiving autologous marrow transplantation for other solid tumors that infiltrate the marrow.     

Changes in Smoking Prevalence and Number of Cigarettes Smoked Per Day Following the Implementation of a Comprehensive Tobacco Control Plan in New York City

The New York City (NYC) Health Department has implemented a comprehensive tobacco control plan since 2002, and there was a 27% decline in adult smoking prevalence in NYC from 2002 to 2008. There are conflicting reports in the literature on whether residual smoker populations have a larger or smaller share of “hardcore” smokers. Changes in daily consumption and daily and nondaily smoking prevalence, common components used to define hardcore smokers, were evaluated in the context of the smoking prevalence decline. Using the NYC Community Health Survey, an annual random digit dial, cross-sectional survey that samples approximately 10,000 adults, the prevalence of current heavy daily, light daily, and nondaily smokers among NYC adults was compared between 2002 and 2008. A five-level categorical cigarettes per day (CPD) variable was also used to compare the population of smokers between the 2 years. From 2002 to 2008, significant declines were seen in the prevalence of daily smoking, heavy daily smoking, and nondaily smoking. Among daily smokers, there is also evidence of population declines in all but the lowest smoking category (one to five CPD). The mean CPD among daily smokers declined significantly, from 14.6 to 12.5. After an overall decline in smoking since 2002, the remaining smokers may be less nicotine dependent, based on changes in daily consumption and daily and nondaily smoking prevalence. These findings suggest the need to increase media and cessation efforts targeted towards lighter smokers.     

Dual oxidase 1 promotes antiviral innate immunity

Dual oxidase 1 (DUOX1) is an NADPH oxidase that is highly expre-ssed in respiratory epithelial cells and produces H₂O₂ in the airway lumen. While a line of prior in vitro observations suggested that DUOX1 works in partnership with an airway peroxidase, lactoperoxidase (LPO), to produce antimicrobial hypothiocyanite (OSCN⁻) in the airways, the in vivo role of DUOX1 in mammalian organisms has remained unproven to date. Here, we show that Duox1 promotes antiviral innate immunity in vivo. Upon influenza airway challenge, Duox1^−/− mice have enhanced mortality, morbidity, and impaired lung viral clearance. Duox1 increases the airway levels of several cytokines (IL-1β, IL-2, CCL1, CCL3, CCL11, CCL19, CCL20, CCL27, CXCL5, and CXCL11), contributes to innate immune cell recruitment, and affects epithelial apoptosis in the airways. In primary human tracheobronchial epithelial cells, OSCN⁻ is generated by LPO using DUOX1-derived H₂O₂ and inactivates several influenza strains in vitro. We also show that OSCN⁻ diminishes influenza replication and viral RNA synthesis in infected host cells that is inhibited by the H₂O₂ scavenger catalase. Binding of the influenza virus to host cells and viral entry are both reduced by OSCN⁻ in an H₂O₂-dependent manner in vitro. OSCN⁻ does not affect the neuraminidase activity or morphology of the influenza virus. Overall, this antiviral function of Duox1 identifies an in vivo role of this gene, defines the steps in the infection cycle targeted by OSCN⁻, and proposes that boosting this mechanism in vivo can have therapeutic potential in treating viral infections.

DUOX1 is one of the seven members of the NADPH oxidase enzyme family (1). DUOX1 was first described in the thyroid gland (2) but was later also detected in several other tissues and organs including the tracheobronchial epithelium (3). DUOX1 localizes to the apical plasma membrane of ciliated respiratory epithelial cells and produces extracellular H₂O₂ into the airway lumen in a Ca²⁺-dependent manner (3, 4). DUOX1 is the major NADPH oxidase expressed and the main source of H₂O₂ in the airway epithelium (3, 5, 6).The respiratory epithelium employs several immune mechanisms against airborne microbes including the generation of reactive oxygen species. Respiratory epithelial cells have a proposed, rapid oxidative and extracellular antimicrobial system consisting of LPO, thiocyanate (SCN⁻), and hydrogen peroxide (H₂O₂) (7–10). LPO is found in a variety of body fluids including milk, saliva, lachrymal, and airway secretions (7, 8, 10–13). Its main substrate, SCN⁻, is abundant in the airway surface liquid (7, 9, 14). LPO oxidizes SCN⁻ into antimicrobial hypothiocyanite (OSCN⁻) using H₂O₂ (15). Prior in vitro data suggested that Duox1 is the epithelial H₂O₂ source that functions in partnership with LPO to produce antimicrobial OSCN⁻(2, 3, 16). SCN⁻ supplementation increases bacterial clearance in mouse lung infection, supporting an antibacterial role of OSCN⁻ in vivo (17, 18). While OSCN⁻ kills several microorganisms in vitro, its mechanism of action and the identity of the in vivo H₂O₂ source required to generate OSCN⁻ remained unknown. The in vivo role of Duox1 in mammals remained unproven to date (13, 19).Influenza remains a major clinical challenge worldwide. Seasonal influenza viruses infect between three and five million people and cause 290,000 to 650,000 global deaths annually (20). In this study, we show that Duox1 promotes innate immunity in vivo against influenza infection in a mouse model. We also identify virus binding and entry into host cells as the basis for the antiviral mechanism of action of OSCN⁻ in vitro. Overall, results shown here demonstrate the in vivo role of Duox1 and determine the steps in the influenza virus life cycle targeted by Duox1- and LPO-derived OSCN⁻.     

A cost-minimization analysis of alternative strategies in diagnosing pancreatic cancer

BACKGROUND: Several modalities currently exist for tissue confirmation of suspected pancreatic cancer prior to therapy. Since there is a paucity of cost-minimization studies comparing these different biopsy modalities, we analyzed costs and examined effectiveness of four alternative strategies for diagnosing pancreatic cancer. METHODS: A decision analysis model of patients with suspected pancreatic cancer was constructed. We analyzed costs, failure rate, testing characteristics, and complication rates of four commonly employed diagnostic modalities: 1) computerized tomography or ultrasound-guided fine-needle aspiration (CT/US-FNA), 2) endoscopic retrograde cholangiopancreatography with brushings (ERCP-B), 3) Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNA), and 4) laparoscopic surgical biopsy. If the first attempt with a particular modality failed, a different modality was employed to identify the most preferable secondary biopsy strategy. RESULTS: This analysis identifies EUS-FNA as the preferred initial modality for the diagnosis of pancreatic cancer. Resultant expected costs and strategies in decreasing optimality include: 1) EUS-FNA (1,405 dollars), 2) ERCP-B (1,432 dollars), 3) CT/US-FNA (3,682 dollars), and 4) surgery (17,711 dollars). If a patient presents with obstructive jaundice, decision analysis modeling resulted in a total expected costs of 1,970 dollars if ERCP-B is successful at the time of biliary stent placement. Additional analyses to identify the preferred follow-up modality after a failed alternative method showed that EUS-FNA is the preferred secondary modality if any of the other three modalities failed first, in both the setting of and absence of obstructive jaundice. One- and two-way sensitivity analysis of the variables shows unchanged results over an acceptable range. CONCLUSIONS: This cost-minimization study illustrates that EUS-FNA is the best initial and the preferred secondary alternative method for the diagnosis of suspected pancreatic cancer. In addition to local expertise and availability, costs and diagnostic yield should be considered when choosing an optimal diagnostic strategy.     

Plasma P-selectin is increased in thrombotic consumptive platelet disorders

P-selectin is a 140-kD protein found in the alpha-granules of platelets and the Weibel-Palade bodies of endothelial cells that on cell activation is expressed on the cell surface and also secreted into the plasma. The secreted form of P-selectin, like plasma P-selectin, differed from platelet membrane P-selectin in that its molecular mass was approximately 3 kD lower under reducing conditions. Both the secreted and plasma forms of P-selectin contained cytoplasmic sequence as determined by Western blot analysis with an affinity-purified rabbit anti-P-selectin cytoplasmic peptide antibody. We have measured plasma P- selectin and beta-thromboglobulin (beta TG) concurrently in (1) patients with consumptive thrombotic disorders, including disseminated intravascular coagulation (DIC), heparin-induced thrombocytopenia (HIT), and thrombotic thrombocytopenic purpura (TTP)/haemolytic uremic syndrome (HUS); (2) patients with idiopathic thrombocytopenic purpura (ITP); and (3) healthy controls. Patients with DIC, HIT, and TTP/HUS, but not ITP, had significantly elevated plasma P-selectin and beta TG levels when compared with their age-matched healthy controls. The increased plasma P-selectin and beta TG in patients with thrombotic disorders were likely to be the result of in vivo platelet and endothelial cell damage or activation. We also found that avoidance of veno-occlusion and other tedious measures customarily taken during blood collection and sample preparation to prevent in vitro platelet activation did not affect plasma P-selectin assay results. In addition, plasma P-selectin levels were not influenced by the presence of renal failure or heparin administration. These results indicate that plasma P- selectin may be a useful new marker for thrombotic diseases.