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Biomedical subjects

D Abramson

Publications and source records attributed to D Abramson.

At least 37 records · Page 2Linked to original sources
PubMed1997

Mycotoxins in fungal contaminated samples of animal feed from western Canada, 1982-1994.

Feed samples from 94 cases involving fungal contamination and suspected mycotoxicosis of farm animals in western Canada were examined during 1982-1994 to assess the incidence of mycotoxins. Samples were analyzed for aflatoxins, ochratoxin A, citrinin, sterigmatocystin, and the fungal estrogen zearalenone. Samples infected with Fusarium fungi were additionally assayed for nivalenol, deoxynivalenol, fusarenone-x, 15-acetyl-deoxynivalenol, diacetoxyscirpenol, HT-2 toxin, and T-2 toxin. Mycotoxins were found in 21 feed samples from 17 cases (18% of the reported cases), generally at levels far below those needed to induce symptoms under laboratory conditions. HT-2 toxin and other type-A trichothecenes were detected in 5 samples, deoxynivalenol and other type-B trichothecenes in 13, ochratoxin A in 5, and citrinin in 2. In 9 cases, symptoms observed in the animals were consistent with the known effects of the mycotoxin(s) found in the particular feed samples.

Animal Feed↗
PubMed1996

Metabolites of ochratoxins in rat urine and in a culture of Aspergillus ochraceus.

We studied the metabolic profile of ochratoxin A (OA) in rats and in a culture of OA-producing Aspergillus ochraceus. Ochratoxin alpha (O alpha), ochratoxin beta (O beta), 4-R-hydroxyochratoxin A (4-R-OH OA), 4-R-hydroxyochratoxin B (4-R-OH OB), and 10-hydroxyochratoxin A (10-OH OA) were isolated from a culture of A. ochraceus and structurally characterized by 1H nuclear magnetic resonance spectroscopy, mass spectrometry and high-pressure liquid chromatography. 4-R-OH OA and O alpha were consistently produced and were the dominant biotransformed metabolites in the fungal culture and in rats treated with OA and ochratoxin C (OC), while the formation of 10-OH OA was conditional in the fungal system. Green fluorescent biomacromolecules were isolated by detergent extraction of the fungal culture followed by cold-acetone precipitation and gel filtration. Acid hydrolysis of the fluorescent macromolecules resulted in the release of several ochratoxins, including O alpha (80%), OA (2%), and OC (5%), and other unidentified fluorescent compounds but not OB and O beta. Cross-reactivity studies of the natural macromolecule conjugates of OA with anti-OA polyclonal antibodies indicated that they were covalently linked to the macromolecules via a group other than the carboxyl group. These studies demonstrated that a fungus can produce some of the same metabolites of OA as the rat and that O alpha, OA, and OC may be covalently linked to fungal macromolecules.

Animals↗
PubMed1995

Nephrotoxigenic Penicillium species occurring on farm-stored cereal grains in western Canada.

The incidence of nephrotoxigenic Penicillium species on farm-stored cereals in western Canada was determined by morphological and metabolite profile examination. Of the 142 isolates examined 102 were toxin producers with 61 P. aurantiogriseum and 27 P. freii. Other nephrotoxigenic species included P. tricolor (6 isolates), P. verrucosum Chemotype II (4 isolates) and P. viridicatum Westling (4 isolates). The nephrotoxigenic Penicillium species profile for western Canada appears to differ from that of Denmark where P. verrucosum, P. cyclopium, P. freii and, to a lesser extent, P. aurantiogriseum, P. polonicum, and P. viridicatum predominate.

Agriculture↗
PubMed1995

An indirect enzyme immunoassay for the mycotoxin citrinin.

An indirect competitive enzyme immunoassay using rabbit antisera could detect citrinin in buffer solutions at 1 to 13 ng/ml (0.05 to 0.65 ng per assay). Cross-reactivity with austdiol, alternariol, ochratoxin A, and deoxynivalenol was < 0.1% relative to citrinin. Recovery of citrinin added to wheat flour at 200 to 2,000 ng/g was 89 to 104%, with a coefficient of variation of 6.9 to 13%.

Animals↗
PubMed1994

Diversion colitis. A prospective study.

A prospective study of patients who had undergone fecal diversion was performed in order to determine the incidence of and to characterize better the condition known as "diversion colitis." A total of 53 patients were studied. All patients underwent endoscopic evaluation of the diverted large bowel. Evidence of colitis was found in 48 patients (91%). The colitis was mild in 52%, moderate in 44%, and severe in only 4%. Endoscopic findings included: contact irritation or bleeding, erythema, and mucosal nodularity. The proximal, "in continuity," colon was examined in 86% of patients with colostomies; none were found to have colitis. Biopsies were taken of the diverted segment in 94% of patients with colitis and from the "in continuity" colon in 78% of patients with colostomies. Similar histologic findings were noted on these biopsies and included: mild chronic inflammation, lymphoid nodules, and crypt architectural changes. With the exception of lymphoid nodules, which were seen more frequently in the inflamed diverted colon (P = 0.035), there was no significant difference in the incidence of the various histologic changes when the biopsies from the diverted and "in continuity" large bowel were compared. Rectal washings and stool samples were sent for bacterial cultures, ova, and parasite analysis, and C. Diff. toxin titers in the majority of patients; all but 1 were negative. Symptoms relating to the diverted bowel were elicited in only 3 patients (6%). Stomal closure was carried in 70% of patients. Postclosure endoscopy in 21 patients revealed full resolution of the colitis in all. Diversion colitis occurs in almost all diverted patients. It uniformly resolves following stomal closure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Structure-activity relationships and interactions among trichothecene mycotoxins as assessed by yeast bioassay.

A yeast (Kluyveromyces marxianus) bioassay was used to establish the relative toxicity of 16 trichothecenes and some of their interactions. Removal of an isovaleryl group, one or two acetyl groups, or two acetyl plus an isovaleryl groups from T-2 toxin (T2) to form diacetoxyscirpenol, HT-2 toxin (HT2), T2-triol and T-2 tetraol (T2-4ol) decreased toxicity 7, 36, 276 and 558-fold, respectively. A combination of T2 and HT2, T2 and T2-4ol, deoxynivalenol (DON) and nivalenol (NIV), or DON and T2 exhibited synergistic (T2 and HT2 or DON and NIV) or antagonistic (DON and T2) responses.

Biological Assay↗
PubMed1993

Lactate clearance and survival following injury.

Previous reports cite optimization of O2 delivery (DO2) to 660 mL/min/m2, O2 consumption (VO2) to 170 mL/min/m2, and cardiac index (CI) of 4.5 L/min as predicting survival. We prospectively evaluated 76 consecutive patients with multiple trauma admitted directly to the ICU from the operating room or emergency department. Patients had serum lactate levels and oxygen transport measured on ICU admission and at 8, 16, 24, 36, and 48 hours. Patients were analyzed with respect to survival (S) versus nonsurvival (NS), lactate clearance to normal (< or = 2 mmol/L) by 24 and 48 hours, hemodynamic optimization as defined above, as well as Injury Severity Score (ISS), ICU stay (LOS), and admission blood pressure. All patients achieved non-flow-dependent VO2. There was no difference in CI, DO2, VO2, or ISS when S was compared with NS. All 27 patients whose lactate level normalized in 24 hours survived. If lactate levels cleared to normal between 24 and 48 hours, the survival rate was 75%. Only 3 of the 22 patients who did not clear their lactate level to normal by 48 hours survived. Ten of the 25 nonsurvivors (40%) achieved the above arbitrary optimization criteria. Fifteen of the survivors never achieved any of these criteria. Optimization alone does not predict survival. However, the time needed to normalize serum lactate levels is an important prognostic factor for survival in severely injured patients.

Adolescent↗