Comparative Oncology Solution to Understanding Hormonal Impact in the Epidemiology of Lymphoma

Introduction:  Surveillance, Epidemiology & End Results (SEER) data indicate that non‐Hodgkin's lymphoma (NHL) is approximately 50% more common among men than women. A similar male predisposition is reported for canine lymphoma, yet the underlying role of gender in lymphoma etiology remains elusive. Because similarities exist between canine lymphoma and NHL, databases including the Veterinary Medical Database (VMDB) and Veterinary Cancer Registry (VCR) may prove useful in understanding lymphoma epidemiology. This study sought to determine the relationship between gender and development of canine lymphoma.
Materials:  Data from 1980 to 2000 were retrieved from the VMDB and sorted by gender and reproductive status. Spayed or neutered dogs diagnosed with lymphoma were compared to intact dogs seen each year in each gender category using a two‐tailed Student's t‐test. The VCR was searched for all canine lymphoma cases. The number of cases in each gender group was compared to the number of cancer diagnoses per group using a Chi‐square test (3 degrees of freedom). Differences were deemed significant when P < 0.050.
Results:  The VMDB included 15,091 lymphoma cases in a population of 1.34 million dogs. In the VCR database, 394 lymphoma cases were identified amongst 6,070 canine cancer diagnoses. In both analyses, intact females were significantly less likely to develop lymphoma than were other gender groups.
Conclusions:  In dogs, as in people, female gender and intact reproductive status appears to be protective against the development of lymphoma. This data suggests that further examination of the role of estrogen in lymphoma prevention is warranted.     

Determination of flavonol metabolites in plasma and tissues of rats by HPLC-radiocounting and tandem mass spectrometry following oral ingestion of [2-(14)C]quercetin-4'-glucoside

Epidemiological studies suggest that consumption of flavonol-rich diets decreases the risk of developing heart disease and certain cancers. Recent studies have detected flavonol conjugates in blood and urine following various dietary interventions. To assess to what extent flavonols also accumulate in tissues, where they might be expected to exert anti-carcinogenic and anti-atherogenic effects, [2-(14)C]quercetin-4'-glucoside was synthesized and fed to rats. After 60 min, 93.6% of the ingested radioactivity was recovered from the intestine, incorporated into 18 metabolites that had undergone deglycosylation followed by varying degrees of glucuronidation, methylation, and/or sulfation. [(14)C]Quercetin, the aglycon of the radiolabeled substrate, was present in the intestine and in trace amounts in the liver but was not detected in the plasma and kidneys. The original [2-(14)C]quercetin-4'-glucoside was detected exclusively in the intestine, where it accounted for only 26.2% of the radioactivity. The remainder of the recovered radioactivity was located mainly in the plasma, liver, and kidneys as (14)C-labeled metabolites. However, compared to the quantities in the gastrointestinal tract, the levels of metabolites in plasma and body tissues were very low, indicating only limited absorption into the blood stream. The data demonstrate that quercetin-4'-glucoside, which is a major flavonol in onions, undergoes rapid and extensive metabolism in the intestine, and this appears not to be associated to any extent with transport across the gut wall into the blood stream.     

Response of Six Australian Plant Species to Heavy Metal Contamination at An Abandoned Mine Site

This investigation was carried out to assess the potential suitability of certain Australian plants for use in the phytoremediation of derelict mine sites. The plant species studied were native to the area surrounding a silver mine at Yerranderie in NSW, Australia, which has been derelict now for over 70 years. The contamination on this site is typical of that caused by acid mine drainage, with very low soil and water pH, and large areas devoid of topsoil and vegetation. Soil metal concentrations exceeded the Australian and New Zealand Environment and Conservation Council (ANZECC) 1992 guidelines for soil quality in several locations. Corresponding topsoil and upper plant samples were collected along three transects crossing the path of drainage from the mine wastes. Six plant species were dominant on the site, including Juncus usitatus (common rush), Lomandra longifolia (spiny-headed mat rush), Cynodon dactylon (couch), Pteridium esculentum (bracken fern), Acacia decurrens (black wattle) and Melaleuca alternifolia (teatree). Of these species, C. dactylon, J. usitatus and L. longifolia were identified as of potential use in phytostabilisation programs, due to tolerance of acid soils and tolerance and/or accumulation of significantly higher concentrations of Pb and Cd than other plant species present on the site.     

Liquid chromatographic determination of total formaldehyde in drinking water

Formaldehyde is readily quantitated at micrograms/L levels in drinking water. The analyte present in 1 L water samples is derivatized with 2,4-dinitrophenylhydrazine in a 2M acid medium and then extracted with chloroform. After the solvent is exchanged for methanol, the product is separated and quantitated using reverse-phase liquid chromatography with UV detection (365 nm). Reporting limits as low as 20 micrograms/L (corrected for laboratory blank) are routinely achieved. Formaldehyde recovery typically exceeds 90% at 20-200 micrograms/L. The method was applied to hot and cold water samples from thirty-four 1- and 2-story houses equipped with poly(acetal) plumbing elbows and tees. The drinking water samples were accompanied by sets of blanks and spikes specified by a quality assurance/quality control plan. Formaldehyde was observed above the reporting limit in 80% of hot and cold water samples from the 1-story dwellings, but in less than 50% of those from the 2-story dwellings. The results may depend on both the construction of the houses (1- vs 2-story) and the time of year the water is sampled (mid-summer).     

Peripheral blood lymphocyte subsets in fleece rot-resistant and -susceptible sheep

Objective To compare haematological values and lymphocyte phenotypes in the peripheral blood of fleece rot-resistant and -susceptible sheep.
Procedure Experiments were conducted on 2- and 3-year-old Merino rams, flock 1 (17 rams) and flock 2 (32 rams), respectively. Within each flock, individual rams were classified as fleece rot-resistant or -susceptible, based on established criteria. Total and differential white cell counts, and indirect fluorescent antibody tests specific for B cells and T cells were performed on all sheep. The concentration of various subsets of circulating lymphocytes was then determined in each sheep.
Results There were no significant differences between fleece rot-resistant and -susceptible sheep from either flock in the mean total or differential white cell counts. However, fleece rot-resistant rams in flock 1 did have a significantly higher concentration of circulating SBU-T1⁺ cells than fleece rot-susceptible rams from the same flock. No such difference was noted in the rams from flock 2. While all rams in flock 1 were free of clinical fleece rot, 24 rams in flock 2 (comprising all 17 fleece rot-susceptible and 7 of 15 fleece rot-resistant animals) had clinical signs of the disease. Fleece rot-free rams in this flock (irrespective of their classification as fleece rot-resistant or -susceptible) had significantly higher concentrations of circulating SBU-T1⁺ cells compared with fleece rot-affected animals. They also had significantly higher concentrations of circulating B cells, and total lymphocytes.
Conclusions An examination of peripheral blood lymphocyte subsets in fleece rot-resistant and -susceptible sheep revealed a possible association between resistance to fleece rot and the concentration of circulating SBU-T1⁺ cells.     

Stratospheric Mean Ages and Transport Rates from Observations of Carbon Dioxide and Nitrous Oxide

Measurements of stratospheric carbon dioxide (CO2) and nitrous oxide (N2O) concentrations were analyzed to investigate stratospheric transport rates. Temporal variations in tropospheric CO2 were observed to propagate into the stratosphere, showing that tropospheric air enters the lower tropical stratosphere continuously, ascends, and is transported rapidly (in less than 1 month) to both hemispheres. The mean age A of stratospheric air determined from CO2 data is approximately 5 years in the mid-stratosphere. The mean age is mathematically equivalent to a conserved tracer analogous to exhaust from stratospheric aircraft. Comparison of values for A from models and observations indicates that current model simulations likely underestimate pollutant concentrations from proposed stratospheric aircraft by 25 to 100 percent.