Regional variation of organic functional groups in aerosol particles on four U.S. east coast platforms during the International Consortium for Atmospheric Research on Transport and Transformation 2004 campaign

Submicron atmospheric aerosol samples were collected during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) 2004 campaign on four platforms: Chebogue Point (Nova Scotia, Canada), Appledore Island (Maine), the CIRPAS Twin Otter over Ohio, and the NOAA R/V Ronald H. Brown in the Gulf of Maine. Saturated aliphatic C-C-H, unsaturated aliphatic C=C−H, aromatic C=C−H, organosulfur C-O-S, carbonyl C=O, and organic hydroxyl C-OH functional groups were measured by calibrated Fourier Transform Infrared (FTIR) spectroscopy at all four sampling platforms. The ratio of molar concentrations of carbonyl C=O to saturated aliphatic C-C-H groups was nearly constant at each sampling platform, with the Twin Otter samples having the lowest ratio at 0.1 and the three more coastal platforms having ratios of 0.4 and 0.5. Organic mass (OM) to organic carbon (OC) ratios follow similar trends for the four platforms, with the Twin Otter having the lowest ratio of 1.4 and the coastal platforms having slightly higher values typically between 1.5 and 1.6. Organosulfur compounds were occasionally observed. Collocated organic aerosol sampling with two Aerodyne aerosol mass spectrometers for OM, a Sunset Laboratory thermo-optical analysis instrument for OC, and an ion chromatography-particle into liquid sampler (IC-PILS) for speciated carboxylic acids provided comparable results for most of the project, tracking the time series of FTIR OM, OC, and carbonyl groups, respectively, and showing simultaneous peaks of similar magnitude during most of the project. The FTIR/IC-PILS comparison suggests that about 9% of the carbonyl groups found in submicron organic particles on the Twin Otter are typically associated with low molecular weight carboxylic acids

Intimal lipid accretion and elevated serum cholesterol in Marek's disease virus-inoculated chickens

In our previous studies of the early pathogenesis of the Marek's disease virus (MDV)-associated model of atherosclerosis, the brachiocephalic arteries and ascending aortas of MDV-inoculated chickens failed to develop lipid accretion and intimal/medial proliferation consistent with atherosclerotic lesions, as described in the original reports of this model. The role of cholesterol supplementation in the formation of MDV-associated atherosclerotic lesions was reexamined. At 3 days of age, 40 chicks were inoculated with the CU-2 strain of MDV. Another 40 chicks were sham inoculated. At 15 weeks postinfection, half of the sham- and MDV-inoculated birds received 2% cholesterol supplementation in the diet for the rest of the experimental period. At 30 weeks postinfection, the aortas and brachiocephalic arteries were evaluated. Several observations were different from the original description of the model. None of the chickens among the four experimental groups developed atherosclerotic lesions, regardless of MDV inoculation or cholesterol supplementation. However, intimal thickening and marked oil red O-positive foam cell accumulation were observed in all 11 MDV-inoculated, cholesterol-supplemented chickens. None of the nine MDV-inoculated, unsupplemented chickens manifested arterial lipid accumulation, despite the presence of an intimal cellular infiltrate. Also in contrast to the original model description, both cholesterol-supplemented and unsupplemented MDV-inoculated chickens manifested significant increases in serum cholesterol in comparison with the respective sham-inoculated groups

Prevalence of coagulase gene polymorphism in Staphylococcus aureus isolates causing bovine mastitis

This study was conducted to investigate polymorphism of the coagulase gene of Staphylococcus aureus causing bovine mastitis. One hundred eighty-seven strains of S. aureus were isolated from bovine mastitic milk samples obtained from 187 different Danish dairy farms. The isolates were characterised for restriction fragment length polymorphism (RFLP) of the coagulase gene. A variable region of the coagulase gene was amplified using the polymerase chain reaction (PCR) followed by AluI restriction enzyme digestion. A total of 15 different RFLP patterns were observed. The predominant pattern was found in 35% of the isolates. The ease of analysing coagulase gene polymorphisms among a large number of strains, and the multiple distinct polymorphic patterns generated, supports the use of this technique in epidemiological investigations of bovine mastitis. The predominating variants may have predelection for causing intramammary infections

Inflammatory bowel disease: an immunity-mediated condition triggered by bacterial infection with Helicobacter hepaticus.

Inflammatory bowel disease (IBD) is thought to result from either an abnormal immunological response to enteric flora or a normal immunological response to a specific pathogen. No study to date has combined both factors. The present studies were carried out with an immunologically manipulated mouse model of IBD. Mice homozygous for the severe combined immunodeficiency (scid) mutation develop IBD with adoptive transfer of CD4+ T cells expressing high levels of CD45RB (CD45RB(high) CD4+ T cells). These mice do not develop IBD in germfree conditions, implicating undefined intestinal flora in the pathogenesis of lesions. In controlled duplicate studies, the influence of a single murine pathogen, Helicobacter hepaticus, in combination with the abnormal immunological response on the development of IBD was assessed. The combination of H. hepaticus infection and CD45RB(high) CD4+ T-cell reconstitution resulted in severe disease expression similar to that observed in human IBD. This study demonstrates that IBD develops in mice as a consequence of an abnormal immune response in the presence of a single murine pathogen, H. hepaticus. The interaction of host immunity and a single pathogen in this murine system provides a novel model of human IBD, an immunity-mediated condition triggered by bacterial infection