Eosinophilic myositis in Canadian cattle.

Musculature from 198 Canadian cattle with suspected lesions of eosinophilic myositis were examined histologically and by pepsin digestion. Sera from 51 of the 198 animals were also examined by enzyme-linked immunosorbent assay (ELISA) for anti-Trichinella antibodies. Viable larvae of Trichinella were not recovered from any of the cattle but one animal from Ontario tested positive for anti-Trichinella antibodies. Histologically, focal and/or diffuse eosinophilic myositis lesions were observed in 149 (75.2%) of the animals studied. Other conditions identified were sarcocystiosis, abscesses, cysticercosis, steatosis, fibrosis, granuloma, lymphosarcoma and necrosis. Sarcocystiosis was identified in 105 of the 198 animals in both normal and affected musculature. The study indicates that trichinosis is not a primary cause of eosinophilic myositis in cattle.     

Cancer-protective properties of high-selenium broccoli

Selenium (Se) from high-Se garlic reduces the incidence of chemically induced mammary tumors, and Se from high-Se broccoli reduces colon cancer. However, the ability of Se from high-Se broccoli to protect against mammary cancer has not been tested. Also, the sprout form of broccoli contains many secondary plant compounds that are known to reduce cancer risk, but the anticarcinogenic activity of broccoli sprouts has not been investigated. The present studies examined the ability of high-Se broccoli or high-Se broccoli sprouts to protect against chemically induced mammary or colon cancer. In one experiment, Sprague--Dawley rats that consumed diets containing 3.0 microg of Se/g supplied as high-Se broccoli had significantly fewer mammary tumors than rats fed 0.1 microg of Se as selenite with or without the addition of regular broccoli. In the second experiment, Fisher F-344 rats fed 2.0 microg of Se/g of diet supplied as either high-Se broccoli florets or high-Se broccoli sprouts had significantly fewer aberrant colon crypts than rats fed 0.1 or 2 microg of Se/g of diet supplied as selenite with or without the addition of low-Se broccoli. These data demonstrate that the cancer-protective effect of Se in high-Se broccoli extends to mammary cancer and the protective forms of broccoli against colon cancer include high-Se broccoli sprouts.     

Studies on Mycoplasma mycoides subsp. mycoides (LC) in lambs and calves.

Six cesarean-derived lambs were inoculated either with 4.5 X 10(4), 4.5 X 10(6) or 4.5 X 10(8) Mycoplasma mycoides subsp. mycoides intratracheally. One animal receiving the intermediate dose died four days post-inoculation, the two receiving the high dose died six days postinoculation, while one receiving the low dose died eight days postinoculation. The two surviving lambs were challenged on day 20 postinoculation with 1 X 10(8) organisms subcutaneously and 2 X 10(9) organisms intravenously. One animal died eight days following this challenge while the other survived and was killed. Six conventionally reared lambs challenged with 90 to 8500 organisms by intranasal and intraocular instillation failed to become infected. Three conventionally reared calves were each inoculated with 1 X 10(8) organisms by each of intratracheal, subcutaneous and intravenous routes. They were killed 20 days post-inoculation without having shown any clinical signs.     

The formation of chondrules: petrologic tests of the shock wave model

Chondrules are millimeter-sized rounded igneous rocks within chondritic meteorites. Their textures and fractionated mineral chemistries suggest that they formed by repeated, localized, brief (minutes to hours) melting of cold aggregates of mineral dust in the protoplanetary nebula. Astrophysical models of chondrule formation have been unable to explain the petrologically diverse nature of chondrites. However, a nebular shock wave model for chondrule formation agrees with many of the observed petrologic and geochemical properties of chondrules and shows how particles within the nebula are sorted by size and how rims around chondrules are formed. It also explains the volatile-rich nature of chondrule rims and the chondrite matrix.     

Timber harvesting as ongoing disturbance in a landscape of diverse ownership

Although the northeastern US includes extensive areas of aggrading forest, uncertainty regarding the intensity and pattern of forest harvesting hampers an understanding of important ecological processes and characteristics such as carbon and nitrogen storage, habitat quality, and forest dynamics, and impedes regional conservation and management planning. Due to the complex ownership pattern dominated by thousands of non-industrial private forest (NIPF) owners and the difficulty of detecting selective logging using remote sensing, details of the harvesting regime remain largely unknown to the scientific and policy communities. To examine the value of statewide regulatory data for Massachusetts as a unique source of this critical information, we analyzed 17 years of timber harvest data gathered for regulatory purposes for a 168,000 ha forested landscape in Massachusetts that is the focus of concerted conservation planning and intensive study of landscape and ecosystem pattern and process. The North Quabbin Region is heavily wooded with a complicated ownership pattern dominated by over 2500 NIPF owners, three state agencies, and diverse conservation and municipal holdings.

The extent and intensity of harvesting were surprising, with an annual disturbance rate of 1.5% and a mean intensity of 44.7 m³ ha⁻¹ (approximately one-fourth of average stand volume). The predominant form of harvesting was selective removal of commercially valuable tree sizes, grades and species (e.g., Quercus rubra and Pinus strobus). The spatial pattern of logging was random with regards to major physical, biological, or cultural factors. However, logging was strongly related to landowner class. NIPF owners control 60% of the forest area and were responsible for 64.1% of harvest area, but the highest logging intensity (volume per area harvested; 69.3 m³ ha⁻¹) among major landowners was conducted by the state agency responsible for managing southern New England’s largest conservation property, the watershed of Boston’s drinking reservoir.

This regime of chronic disturbance is occurring over the entire landscape and exerting a major influence on forest composition, dynamics, and habitat quality. However, dispersed selective harvesting is largely unnoticed by residents, is routinely overlooked by ecologists and conservationists, and would remain unrecognized in the absence of this previously unused regulatory data. These results identify the value of regional regulatory spatial information to estimate ecological trends and to assist in conservation planning. Given similarities among ownership and forest patterns for much of the northeastern US, we expect that the broad findings of this study to have regional application.     

The Solar Acoustic Spectrum and Eigenmode Parameters

The Global Oscillation Network Group (GONG) project estimates the frequencies, amplitudes, and linewidths of more than 250,000 acoustic resonances of the sun from data sets lasting 36 days. The frequency resolution of a single data set is 0.321 microhertz. For frequencies averaged over the azimuthal order m, the median formal error is 0.044 microhertz, and the associated median fractional error is 1.6 x 10(-5). For a 3-year data set, the fractional error is expected to be 3 x 10(-6). The GONG m-averaged frequency measurements differ from other helioseismic data sets by 0.03 to 0.08 microhertz. The differences arise from a combination of systematic errors, random errors, and possible changes in solar structure.     

Nutritional responses in rainbow trout (Oncorhynchus mykiss) fed diets with different physical qualities at stable or variable environmental conditions

Rainbow trout with initial body weight 1144 g were fed two diets with high (feed A) or low (feed B) water stability for 6 weeks. During the last 2 weeks either stable or fluctuating oxygen saturation, salinity and temperature was introduced. High water stability of the feed was associated with harder pellets, less dust formation and less broken pellets compared to feed with low water stability. During the first 4 weeks, feed intake was 23% higher in trout fed diet B than in those fed diet A. Fluctuating environment resulted in a severe drop in feed intake for both dietary groups. At termination of the trial, stomachs of trout fed feed B contained mashed pellets and free water and oil. Stomachs of trout fed feed A contained more intact pellets and little fluid. The apparent digestibility of protein, starch, dry matter and energy was highest in feed A. The apparent digestibility of P and Zn was highest at stable environment, and the absorption of P was highest from feed A. In conclusion, physical quality affected the nutritional value of the feeds, and differences in nutritional value at stable or fluctuating environment appeared to be related to feed intake.     

Competitive exclusion of Yersinia enterocolitica biotype 4, serotype O:3 by Yersinia enterocolitica biotype 1A,serotype O:6,30 in tissue culture and in pigs

AIMS: To study the adhesion properties of a biotype 4, serotype O:3 (human pathogenic) strain of Yersinia enterocolitica and to determine if adhesion in vitro and colonisation in vivo can be prevented by competition with a biotype 1A, serotype O:6,30 (non-pathogenic) strain. To study interaction between Y. enterocolitica biotype 4, serotype O:3 and cultured epithelial cells using the synthetic tripeptide arginine-glycine-aspartic acid (RGD).

METHODS: The human intestinal epithelial (HEp-2) cell line was used for in vitro studies. Inocula of Y. enterocolitica biotype 4, serotype O:3 radiolabelled using tritium were incubated with HEp-2 cells and RGD tripeptide, or with Y. enterocolitica biotype 1A, serotype O:6,30 sequentially or concurrently, then washed and lysed, and radioactivity measured to determine the effect of RGD on adhesion, and competitive exclusion of pathogenic by non-pathogenic bacteria. For in vivo studies, two groups of 5-week-old piglets (n=5/group) were sequentially inoculated orally with 5x10⁹ colony forming units (cfu) of either a non-pathogenic biotype 1A, serotype O:6,30 strain of Y. enterocolitica followed by a pathogenic biotype 4, serotype O:3 strain, or vice versa. Pigs were monitored for carriage of strains using bacterial culture and a multiplex polymerase chain reaction (PCR).

RESULTS: The RGD tripeptide significantly inhibited adherence of the pathogenic Y. enterocolitica strain to cultured epithelial cells, suggesting that adhesion involved the RGD tripeptide sequence. The non-pathogenic biotype 1A, serotype O:6,30 strain of Y. enterocolitica prevented adhesion of the pathogenic strain to cells in vitro when allowed to adhere first. Pathogenic Y. enterocolitica was consistently isolated from rectal swabs from 80-100% of pigs on all sampling occasions but not from oral swabs after 14 days in pigs first inoculated with the non- pathogenic strain or at 26 days in pigs first inoculated with the pathogenic strain.

CONCLUSIONS: A non-pathogenic strain of Y. enterocolitica reduced adhesion of a human pathogenic strain in vitro but not in vivo.