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Biomedical subjects

P F Ross

Publications and source records attributed to P F Ross.

At least 19 recordsLinked to original sources
PubMed2002

An international collaborative study on a method for determination of formaldehyde in veterinary vaccines.

An international collaborative study of a quantitative colorimetric method for determination of formaldehyde in veterinary vaccines was conducted on a series of replicate, blinded veterinary vaccine products by 15 laboratories in three regions: North America, Europe and Japan. Participants conducted determinations using a modification of a method from the European Pharmacopoeia, a colorimetric method based on the reaction of formaldehyde with methylbenzothiazolone hydrazone hydrochloride. For this study, three licensed vaccine products containing formaldehyde were revialed, randomly numbered, tested for uniformity and distributed by one of the participating laboratories through regional coordinators to collaborators. One of the revialed products was spiked with a known amount of formaldehyde and included in the test series. Results along with all raw data were returned to the distributing laboratory for consolidation and statistical treatment. For the modified method spike recovery was 101% and reproducibility (inter-laboratory variation expressed as relative standard deviation) ranged from 18.0 to 8.0% for respective formaldehyde concentrations of 0.28 to 1.07 g/l. Based on the study, the method was proposed by the Biologicals Working Group of the International Cooperation on Harmonization of Technical Requirements for Registration of Veterinary Medicinal Products (VICH) as a candidate for the VICH Guideline standard method for residual formaldehyde.

Chlorine↗
PubMed2001

Fumonisin B1 promotes aflatoxin B1 and N-methyl-N'-nitro-nitrosoguanidine-initiated liver tumors in rainbow trout.

Laboratory studies have described the carcinogenicity of fumonisin B1 (FB1) in rodents and epidemiological evidence suggests an association between FB1 (a mycotoxin produced by Fusarium moniliforme) and cancer in humans. This study was designed to reveal in rainbow trout, a species with very low spontaneous tumor incidence, if FB1 was (i) a complete carcinogen, in the absence of an initiator; (ii) a promoter of liver tumors in fish initiated as fry with aflatoxin B1 (AFB1); and (iii) a promoter of liver, kidney, stomach, or swim bladder tumors in fish initiated as fry with N-methyl-N'-nitro-nitrosoguanidine (MNNG). FB1 was not a complete carcinogen in trout. No tumors were observed in any tissue of fish fed diets containing 0, 3.2, 23, or 104 ppm FB1 for a total of 34 weeks (4 weeks FB1 exposure, 2 weeks outgrowth on control diet, followed by 30 weeks FB1 diet) in the absence of a known initiator. FB1 promoted AFB1 initiated liver tumors in fish fed > or = 23 ppm FB1 for 42 weeks. A 1-week pretreatment of FB1 did not alter the amount of liver [3H]AFB1 DNA adducts, which suggests that short-term exposure to FB1 will not alter phase I or phase II metabolism of AFB1. In MNNG-initiated fish, liver tumors were promoted in the 104 ppm FB1 treatment (42 weeks), but FB1 did not promote tumors in any other tissue. Tumor incidence decreased in kidney and stomach in the 104 ppm FB1 treatment of MNNG-initiated trout. The FB1 promotional activity in AFB1-initiated fish was correlated with disruption of sphingolipid metabolism, suggesting that alterations in associated sphingolipid signaling pathways are potentially responsible for the promotional activity of FB1 in AFB1-initiated fish.

Aflatoxin B1↗
PubMed1999

Serum copper concentrations in beef cows and heifers.

OBJECTIVE: To characterize serum copper status of cows and heifers in beef cow-calf herds throughout the United States and to evaluate use of copper supplements in those herds. DESIGN: Cross-sectional survey. ANIMALS: 2,007 cows and heifers from 256 herds in 18 states. PROCEDURES: Producers participating in a health and management survey conducted as part of the National Animal Health Monitoring System voluntarily allowed serum samples to be obtained from cows and heifers for determination of copper concentration. Results were categorized as deficient, marginally deficient, or adequate. The proportion of cattle and herds (on the basis of mean value of the tested cattle) in each category was determined. Copper concentrations were compared between herds that reportedly used copper supplements and those that did not. RESULTS: Overall, 34 of 2,007 (1.7%) cows and heifers were deficient in copper, and 781 (38.9%) were marginally deficient. In each region, at least a third of the cattle were deficient or marginally deficient. For herds, 92 of 256 (35.9%) were marginally deficient, and 22 (0.8%) were deficient. Approximately half of the producers reported use of copper supplements, but a sizeable proportion of those producers' cattle and herds were classified as marginally deficient or deficient. CONCLUSIONS AND CLINICAL RELEVANCE: Copper deficiency is not restricted to a single geographic region of the United States. Copper deficiency can persist despite reported use of supplements by producers. Veterinarians dealing with beef cow-calf herds that have problems consistent with copper deficiency should not rule out copper deficiency solely on the basis of geographic region or reported use of copper supplements for the herd.

Animal Feed↗
PubMed1996

Natural occurrence of gliotoxin in turkeys infected with Aspergillus fumigatus, Fresenius.

Thirteen samples of infected turkey lung tissue from cases of 'airsacculitis' were collected either at the processing plant or from a local turkey farm and subjected to cultural and gliotoxin analysis. Aspergillus fumigatus was isolated from 6 of the 13 samples; all isolates were determined to be gliotoxin producers when grown in laboratory culture and assayed by HPLC procedures. Gliotoxin was isolated from 5 of the 13 tissue but was not isolated from all tissues that were infected with A. fumigatus. Gliotoxin was isolated from which no A. fumigatus was isolated and it was not detected in three tissues from which gliotoxin-producing isolates of A. fumigatus were obtained. The ability of this pathogenic fungs to produce this immunomodulating compound in naturally infected turkeys provides further evidence that gliotoxin may be involved in the pathogenesis of the disease, aspergillosis of turkeys.

Animals↗
PubMed1996

Absence of detectable fumonisins in the milk of cows fed Fusarium proliferatum (Matsushima) Nirenberg culture material.

Fumonisins, a group of mycotoxins produced by the ubiquitous fungi Fusarium moniliforme and F. proliferatum, were first identified about eight years ago. They have been shown to cause a variety of health effects in animals, including epidemiological evidence of esophageal cancer in humans. Cattle are less sensitive to ill effects than horses and swine. Fumonisins are common contaminants of low quality grain fed to cattle. Culture material containing fumonisins (FB1, FB2, and FB3) was mixed into the total diet and fed for 14 days to two midlactation Jersey cows to determine if fumonisins are excreted in milk. The dietary equivalent of fumonisin was approximately 75 ppm and the two cows consumed an average of 3 mg fumonisin B1/kg body weight (bwt)/day. Fumonisins were not detected in any of the milk samples by two analytical laboratories using methods with a sensitivity of 5 ng/ml. Except for transient diarrhea at the beginning of the contaminant feeding period and an increase in serum cholesterol, clinical and hematologic changes were not observed in the animals. The appearance or carry over of fumonisins from feed to milk in dairy cows does not appear to be significant and likely not a hazard or food safety concern for humans.

Animal Feed↗
PubMed1996

Blood selenium concentrations in cows and heifers on 253 cow-calf operations in 18 states.

This study was conducted to determine the geographic distribution of selenium deficiency among beef cows and heifers in selected states. Whole blood selenium concentrations were determined for cows and heifers on 253 cow-calf operations in 18 states. Overall, 7.8% of the samples were severely deficient, and another 10.4% of the samples were considered marginally deficient for selenium. Blood selenium concentrations varied by geographic region. Cattle from the southeastern states were more commonly considered severely or marginally deficient (18.6% and 23.8%, respectively) than cattle from other regions. Herds from the southeastern states were also more commonly considered severely or marginally deficient (14.9% and 20.9%, respectively) than herds from other regions. Blood selenium concentration also varied by whether selenium had been supplemented to the herd. We conclude that blood selenium levels for cattle vary by geographic region and selenium supplementation of the herd.

Animals↗
PubMed1995

Effects of feeding fumonisin B1 in lactating sows and their suckling pigs.

The mycotoxin fumonisin B1 (FB1) produced by Fusarium moniliforme in corn causes pulmonary edema in finishing swine. Effects of lower nonlethal amounts and effects in lactating sows with suckling pigs are unknown. An initial study was conducted to determine a nonlethal concentration of FB1 for lactating sows; whether ingested FB1 could be detected in the milk; and whether toxicosis could be detected in the pigs, as determined by necropsy. Another study was conducted to determine toxicosis in the pigs by measuring liver sphinganine-to-sphingosine ratio, and whether ingested FB1 affected T-lymphocyte function in sows and their pigs. Furthermore, sows of this study were maintained in controlled hot (27 to 32 C, 50 to 70% relative humidity) and thermoneutral (21 C, 55% relative humidity) environments to determine whether high temperature exacerbated the effects of FB1. In the first study, 100 micrograms of FB1/g of corn soybean meal diet was found to be nonlethal when fed for 14 days. Fumonisin B1 was not detected in the milk at 30 ppb and lesions were not found in the necropsied pigs, including 1 from a sow that died of porcine pulmonary edema syndrome after ingesting FB1 at a concentration of 175 ppm. In the second study, differences in liver sphinganine-to-sphingosine ratio of pigs were not found. Expressions of cell surface antigens on blood lymphocytes and lymphocyte proliferation response to various mitogens were not affected by FB1 or high temperature in sows or their pigs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Quality assurance initiative at the U.S. Department of Agriculture National Veterinary Services Laboratories.

The National Veterinary Services Laboratories (NVSL) provides laboratory support and technical assistance for animal health programs of the United States Department of Agriculture. During this past year, the NVSL completed strategic planning activities and identified improved quality assurance (QA) as one of the key elements. The specific QA goal was the establishment of an internationally recognized QA program at the NVSL by the year 2000. This article provides a brief summary of the mission of the NVSL and the short- and long-term goals of the QA initiative.

Animal Husbandry↗
PubMed1993

Experimental equine leukoencephalomalacia, toxic hepatosis, and encephalopathy caused by corn naturally contaminated with fumonisins.

A study to evaluate the effects of dietary fumonisin B1 was conducted using 6 ponies (4 test and 2 control). A ration naturally contaminated with fumonisin B1 was fed in 3 phases: 1) 44 ppm fumonisin B1, 2) less than 1 ppm fumonisin B1, and 3) 88 ppm fumonisin B1. All ponies were monitored daily, weighed weekly, and limit fed at a rate of 0.8% body weight plus hay. Feed intake was measured daily, and a serum chemistry panel was completed once or twice weekly. Four to 7 days after initiation of the trial (Phase 1), all 4 test ponies had decreased feed consumption, and selected serum chemistry parameters were markedly elevated. On day 9, 1 pony died acutely with mild encephalopathy and hepatic necrosis. Another pony, euthanized on day 45, also had mild encephalopathy and hepatic necrosis. The remaining 2 test ponies continued the 44 ppm fumonisin B1 diet for 98 days. Phase 2 consisted of a diet with < 1 ppm fumonisin B1 for 120 days. During this phase, the serum chemistry values of the 2 ponies returned to normal. Following Phase 2, the 2 ponies were fed a diet containing 88 ppm fumonisin B1. After 75 days, 1 animal died of equine leukoencephalomalacia with mild hepatic necrosis. On day 78, the remaining pony was euthanized after showing distress; it also had leukoencephalomalacia and hepatic lesions.

Animal Feed↗
PubMed1993

An HPLC method for the detection of ergot in ground and pelleted feeds.

A high performance liquid chromatography (HPLC) method is described for detecting ergot in ground or pelleted forages and grains. Samples were extracted with alkaline chloroform, filtered, and applied to silica gel/organic binder cleanup columns. Following elution of pigments with acetone: chloroform, ergopeptine alkaloids were eluted with methanol and analyzed by HPLC with fluorescence detection. Average recovery of ergotamine, the major ergopeptine alkaloid produced by Claviceps, was 93%, with a relative standard deviation of 4.9%. The detection limit of ergotamine was approximately 50 ppb in all feedstuffs. Confirmation of ergopeptine alkaloids was accomplished by treating the parent ergopeptine alkaloids with 0.2% acetic acid to produce their -inine isomers and reexamining by HPLC with fluorescence detection or silica gel/organic binder column cleanup in combination with tandem mass spectroscopy. The method described is a valid alternative to microscopic inspection for detecting ergot contamination in ground or pelleted feedstuffs.

Animal Feed↗
PubMed1993

Effects of fumonisin-contaminated corn screenings on growth and health of feeder calves.

Fumonisins are myocotoxins produced by Fusarium moniliforme and F. proliferatum, common molds of corn in North America. The toxin is at especially high concentrations in corn screenings. Fumonisins are toxic to swine and horses, but effects of these toxins in cattle have not been evaluated. This experiment was conducted to determine the effects in cattle of feeding fumonisins at levels known to be toxic to swine and horses. A total of 18 crossbred feeder calves were fed diets containing fumonisins at 15, 31, or 148 micrograms/g for 31 d. Feed consumption, weight gain, complete blood count, serum clinical chemistries, and an immune function profile were done on d -3, 4, 10, 17 and 31 relative to the start of fumonisin feeding. There was no treatment-related effect on feed intake or weight gain, but feed containing 148 micrograms/g of fumonisins seemed to be less palatable than other feeds. Significant increases in serum aspartate amino transferase, gamma glutamyl transpeptidase, lactate dehydrogenase, bilirubin, and cholesterol occurred from d 10 through 31. Mild microscopic liver lesions were present in two calves fed at the highest fumonisin level. Lymphocyte blastogenesis was significantly impaired at the end of the feeding period in the group given the highest dose. Other measures of immune function were not affected significantly. Fumonisins are capable of causing changes in liver function and in some measures of immune function. However, cattle seem to be relatively less susceptible to fumonisins present naturally in grains than either swine or horses.

Animal Feed↗
PubMed1993

Analysis of naturally occurring mycotoxins in feedstuffs and food.

Aflatoxins, zearalenone, deoxynivalenol, fumonisins, and their respective metabolites require specific procedures for their determination because of their diverse chemistry and occurrence in complex matrices of feedstuffs and foods. Major sources of error in the analysis of these mycotoxins arise from inadequate sampling and inefficient extraction and cleanup procedures. The determinative step in the assay for each of these toxins is sensitive to levels below those that are considered detrimental to humans and animals. Aflatoxins can be determined in grains and animal fluids and tissues by TLC, HPLC, gas chromatography-mass spectrometry (GC-MS), and ELISA procedures. Zearalenone, an estrogenic mycotoxin, can readily be determined in cereal grains and foods by HPLC (50 ng/g) and by TLC (300 ng/g). No incurred levels of zearalenone or its metabolites have been detected in animal tissues destined for human consumption. Deoxynivalenol can be determined in wheat and corn at 300 ng/g by a rapid TLC procedure and at 325 ng/g by a GC method. Although not tested collaboratively, an HPLC procedure and an ELISA screening procedure are capable of detecting deoxynivalenol at low (nanograms/gram) levels in feedstuffs and foods. The recently characterized fumonisins can be detected by TLC, HPLC, and GC-MS at levels below those now considered harmful. Thin-layer chromatography and HPLC (with fluorescence detection of derivatives) procedures can detect fumonisins at approximately 100 ng/g; GC-MS is required for detection at lower levels.

Aflatoxins↗
PubMed1992

A review and update of animal toxicoses associated with fumonisin-contaminated feeds and production of fumonisins by Fusarium isolates.

During the 1989 corn harvest season, numerous reports of equine leukoencephalomalacia (ELEM) outbreaks and a pulmonary edema (PPE) syndrome in swine from several regions of the United States were received by the National Veterinary Services Laboratories (NVSL), Ames, Iowa. Previous and concurrent research linked Fusarium moniliforme and fumonisin-contaminated feeds to both diseases. Chemical and mycological investigations revealed fumonisin B1 (FB1) concentrations of 20 to 360 ppm in suspect swine feeds and 8 to 117 ppm in suspect equine feeds. Nonproblem feeds contained concentrations below 8 ppm. Fusarium moniliforme and Fusarium proliferatum were isolated from both problem and nonproblem equine and swine feeds. When cultured on autoclaved corn, the F. moniliforme and F. proliferatum isolated produced respective FB1 and fumonisin B2 (FB2) that range from less than 5 to more than 2450 ppm and less than 5 to more than 1000 ppm, respectively. Isolates from both problem and nonproblem feeds produces high levels (greater than 500 ppm) in culture. Reported here is a review of chemical and mycological data resulting from the study of several cases of PPE and ELEM.

Animal Feed↗
PubMed1992

Experimental reproduction of ELEM. A study to determine the minimum toxic dose in ponies.

An experiment to gain insight into the minimum toxic dose of fumonisins was conducted by feeding ponies rations with known fumonisin concentrations. Naturally contaminated corn screenings (CS) were blended with pellets, corn, and molasses to formulate individual daily diets. One group of 4 ponies was fed a ration with fumonisin B1 (FB1) varying from less than 1 ppm to 22 ppm. A second group of 5 ponies was fed a ration at varying rates containing 8 ppm FB1 for 180 days. A panel of clinical chemistry parameters was evaluated twice weekly for both groups. One pony in the first group died of equine leukoencephalomalacia (ELEM) after 225 days of which the final 55 days' diet contained 22 ppm FB1. Approximately 9 days prior to death, this animal experienced elevated liver chemistry values. All 5 ponies in the second group experienced mild, transient, clinical signs; were euthanized at 180 days; and had mild, histopathological brain lesions.

Animal Feed↗
PubMed1992

Increases in serum sphingosine and sphinganine and decreases in complex sphingolipids in ponies given feed containing fumonisins, mycotoxins produced by Fusarium moniliforme.

Consumption of food contaminated with Fusarium moniliforme causes leucoencephalomalacia and hepatotoxicity in horses, pulmonary edema in pigs and liver cancer in rats, and has been correlated with esophageal cancer in humans. The causative agents are thought to be a family of compounds called fumonisins, which have recently been shown to be potent inhibitors of sphingosine (sphinganine) N-acyltransferase. Because inhibition at this step blocks the formation of complex sphingolipids while leading to accumulation of sphinganine, we hypothesized that exposure of animals to fumonisin-contaminated feed might be detected by analyses of serum sphingolipids. Within days of giving ponies feed contaminated with 15 to 44 micrograms/g fumonisin B1, there was an increase in the amount of free sphinganine (and sometimes sphingosine) and a reduction in complex sphingolipids. Free sphinganine and sphingosine decreased when ponies consumed less of the contaminated feed, and increased again when they consumed more fumonisin. When toxicosis was evident as indicated by other serum markers, complex sphingolipids as well as free sphingosine and sphinganine were elevated, probably due to loss of sphingolipids from dying cells. These findings establish that consumption of fumonisin-contaminated feed disrupts sphingolipid metabolism. Because the changes in sphinganine and sphingosine were seen before liver enzymes were noticeably elevated, they may be an early marker of exposure to fumonisins.

Animal Feed↗
PubMed1992

Characterization of an epizootic of pulmonary edema in swine associated with fumonisin in corn screenings.

In 1989, corn screenings were associated with acute interstitial pulmonary edema, hydrothorax, and death in swine. Attack rate was 5-50%, case fatality rate was 50-90%, and clinical course was 1-2 days. Screenings from farms with pigs affected with pulmonary edema contained 20-330 micrograms fumonisin B1 per gram. Screenings containing 92 micrograms fumonisin B1 per gram fed to weanling pigs caused pulmonary edema and death. Sterilized corn inoculated with Fusarium moniliforme and diluted 1:1 with clean corn contained fumonisin B1 (17 micrograms/g) and caused acute pulmonary edema when fed for 5 days. Survivors developed subacute hepatotoxicosis with individual hepatocellular necrosis, hepatomegalocytosis, and increased numbers of mitotic figures. Similar liver lesions occurred in pigs given fumonisin B1 intravenously at 0.8 mg/kg body weight for 14 days.

Animal Feed↗