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Biomedical subjects

D Abramson

Publications and source records attributed to D Abramson.

At least 19 recordsLinked to original sources
PubMed1992

Ochratoxin A production in Bavarian cereal grains stored at 15 and 19% moisture content.

Wheat, barley, and maize, each in 15-kg parcels at 15 and 19% initial moisture content (IMC), were kept in a Bavarian farm granary from June through November 1990. During this period, the grain at each IMC was analyzed for mycotoxins and monitored for grain temperature, carbon dioxide, seed germination, and microfloral incidence and abundance. Barley and maize stored for 20 weeks at 19% IMC contained ochratoxin A in amounts of 70 and 90 microg/kg, respectively. This mycotoxin was not detected in wheat stored at 19% IMC, nor in the grains stored at 15% IMC. Aflatoxin B1, sterigmatocystin, citrinin, and zearalenone were also assayed but not detected in grains stored at either IMC. Principal component analysis of the data indicated that ochratoxin A was produced in a damp niche in maize, when abundant metabolic activity and CO2 production by Penicillium glandicola and Aspergillus spp. were common.

Edible Grain↗
PubMed1991

Cobalt60 plaques in recurrent retinoblastoma.

Cobalt60 plaque irradiation is one treatment option for patients with recurrent retinoblastoma following conventional external beam irradiation (ERT). Tumorocidal doses can be delivered without excessive risk of normal tissue injury. In patients not considered candidates for xenon arc or cryotherapy, 60Co is an alternative to enucleation. Between 1968 and 1987, 85 patients were treated with 60Co plaques, 72 of whom had failed prior ERT. Age at diagnosis ranged from 1 week to 4 years. There are 37 males and 35 females. Seventy-one patients had bilateral disease and one had unilateral. Three patients had both eyes plaqued. Prior ERT ranged from 30 to 70 Gy (mean 4200 Gy). Time from initial therapy to failure ranged from 13 to 60 months. Cobalt plaques of 10 mm, 15 mm, or 10 x 15 mm were used depending on tumor size and location. Dose prescribed to the apex of the tumor ranged from 30 to 50 Gy (median 40 Gy) given over 3 to 8 days. Twelve patients had two plaque applications; three patients had three plaque applications. All patients were followed with routine ophthalmoscopic examinations. Follow-up ranged from 2 to 22 years (mean 8.7). Seven patients died of metastatic disease; 10 patients developed non-ocular second tumors. Thirty patients required enucleation. Twenty-two patients had clear tumor progression, two patients had radiation complications, and six patients had a combination of tumor growth and complications. Cobalt60 can salvage eyes in retinoblastoma patients failing ERT. Currently, we are using I125 in an attempt to spare normal ocular tissue and reduce subsequent complications.

Brachytherapy↗
PubMed1990

Mycotoxin formation in HY-320 wheat during granary storage at 15 and 19% moisture content.

Eleven-kilogram parcels of HY-320 wheat, a cultivar of the new Canada Prairie Spring class, were kept at 15 and 19% initial moisture contents (IMC) in simulated storage in a Manitoba farm granary for 60 weeks to determine biotic and abiotic changes and mycotoxin production. Ochratoxin A reached a maximum of 0.24 ppm by week 20 in the 19% IMC wheat, but was absent in the 15% IMC wheat; no other mycotoxins were detected. Temperature, moisture content, O2 and CO2 levels, fat acidity values, seed germination, microfloral incidence and abundance, and the presence of other mycotoxins were monitored. Principal component analysis of all variables showed that the first principal components accounted for 32-41% of the system variability, and contained the ochratoxin A variable. Ochratoxin A was produced in moist grain that had decreased seed germination and Alternaria activity, and high fungal activity by Penicillium and Aspergillus versicolor. Compared to other stored cereals previously studied, HY-320 wheat would be ranked in a low-risk category for mycotoxin formation, based on the ochratoxin A levels observed.

Carbon Dioxide↗
PubMed1990

Ochratoxin A: an important western Canadian storage mycotoxin.

Ochratoxin A (OA) is a mycotoxin produced by certain species of storage fungi of the Penicillium and Aspergillus genera. Toxin production by these fungi is influenced by species and even strain of fungi, time and temperature of incubation, moisture content of substrate, and type of substrate. OA has been shown to occur in various grains, cereals and other plant products, animal feeds, meats, and human tissues in countries throughout the world. Of interest is the discovery of OA in a high percentage of blood from humans in Germany. OA is acutely toxic to many different animals and in addition to being a nephrotoxin, it is a hepatotoxin, a teratogen, a very potent carcinogen, possibly a mutagen, and an immunosuppressive agent. OA is rapidly absorbed throughout the entire gastrointestinal tract and distributes itself in the body as a two-compartment open model and has a particular high affinity for serum albumin. OA is hydrolyzed by the intestinal microflora into nontoxic compounds (7-carboxy-5-chloro-8-hydroxy-3,4-dihydro-3R-methylisocoumarin (O alpha) and phenylalanine). It is excreted as either OA, hydroxylated OA, or O alpha in both the urine and feces. OA appears to exert its toxic effect by promoting an increased level of lipid peroxidation, by inhibition of an amino acylation reaction, and possibly by conversion into metabolites that are capable of binding DNA. These in turn cause other secondary effects associated with OA. It would appear that this compound presents a true potential hazard for humans as its occurrence is wide spread and it is highly carcinogenic.

Animal Feed↗
PubMed1989

Odor volatiles associated with microflora in damp ventilated and non-ventilated bin-stored bulk wheat.

Western hard red spring wheat, stored at 20 and 25% moisture contents for 10 months during 1985-86, was monitored for biotic and abiotic variables in 10 unheated bins in Winnipeg, Manitoba. The major odor volatiles identified were 3-methyl-1-butanol, 3-octanone and 1-octen-3-ol. The production of these volatiles was associated and correlated with microfloral infection. Ventilation, used for cooling and drying of grain, disrupted microfloral growth patterns and production of volatiles. The highest levels of 3-methyl-1-butanol occurred in 25% moisture content wheat infected with bacteria, Penicillium spp. and Fusarium spp. In non-ventilated (control) bins with 20% moisture content wheat, 3-methyl-1-butanol was correlated with infection by members of the Aspergillus glaucus group and bacteria. In control bins, 1-octen-3-ol production was correlated with infection of wheat of both moisture contents by Penicillium spp. The fungal species, isolated from damp bin-stored wheat and tested for production of odor volatiles on wheat substrate, included Alternaria alternata (Fr.) Keissler, Aspergillus repens (Corda) Saccardo, A. flavus Link ex Fries, A. versicolor (Vuill.) Tiraboschi, Penicillium chrysogenum Thom, P. cyclopium Westling, Fusarium moniliforme Sheldon, F. semitectum (Cooke) Sacc. In the laboratory, fungus-inoculated wheat produced 3-methyl-1-butanol; 3-octanone and 1-octen-3-ol were also produced, but less frequently. Two unidentified bacterial species isolated from damp wheat and inoculated on agar produced 3-methyl-1-butanol.

Alcohols↗
PubMed1988

Fungal volatiles associated with moldy grain in ventilated and non-ventilated bin-stored wheat.

The fungal odor compounds 3-methyl-1-butanol, 1-octen-3-ol and 3-octanone were monitored in nine experimental bins in Winnipeg, Manitoba containing a hard red spring wheat during the autumn, winter and summer seasons of 1984-85. Quality changes were associated with seed-borne microflora and moisture content in both ventilated and non-ventilated bins containing wheat of 15.6 and 18.2% initial moisture content. All three odor compounds occurred in considerably greater amounts in bulk wheat in non-ventilated than in ventilated bins, particularly in those with wheat having 18.2% moisture content. The presence of these compounds usually coincided with infection of the seeds by the fungi Alternaria alternata (Fr.) Keissler, Aspergillus repens DeBarry, A. versicolor (Vuill.) Tiraboschi, Penicillium crustosum Thom, P. oxalicum Currie and Thom, P. aurantiogriesum Dierckx, and P. citrinum Thom. High production of all three odor compounds in damp wheat stored in non-ventilated bins was associated with heavy fungal infection of the seeds and reduction in seed germinability. High initial moisture content of the harvested grain accelerated the production of all three fungal volatiles in non-ventilated bins.

Alternaria↗
PubMed1988

Radiation therapy for retinoblastoma: comparison of results with lens-sparing versus lateral beam techniques.

From 1979 through 1986, 170 children were seen at our institution diagnosed with retinoblastoma. Sixty-six of the children with involvement of 121 eyes, were referred for definitive external beam radiation to one or both eyes. During the study period, two distinct radiation techniques were used. From 1980 through mid-1984, a lens-sparing technique included an anterior electron beam with a contact lens mounted lead shield, combined with a lateral field, was used. Since mid-1984, a modified lateral beam technique has been used, mixing lateral electrons and superior and inferior lateral oblique split beam wedged photons. Doses prescribed were similar for both techniques, ranging from 3,850 to 5,000 cGy in 4 to 5 weeks. The lens-sparing and the modified lateral techniques are compared for local control. For eyes with Group I through III disease, the lens-sparing technique resulted in local control in 33% of the eyes treated, where the modified lateral technique controlled 83% of the eyes treated (p = .006). Mean time to relapse was identical in both groups, that is 24 and 26 months respectively. Most relapses were successfully treated with further local therapy, including laser or cryosurgery, or 60Co plaques. Five eyes required enucleation following initial treatment with the lens-sparing technique, but none thus far with the lateral beam technique. For eyes with Group IV and V disease, no significant differences were found between the two techniques in terms of local control or eventual need for enucleation. With a mean follow-up time of 33 months for the entire group, the 4-year survival is 93%. Two of the 4 deaths are due to second primary tumor, and all 4 have occurred in the lens-sparing group. Because follow-up time is more limited in the lateral beam group, this is not statistically significant and direct survival comparisons are premature.

Eye Neoplasms↗
PubMed1988

Studies of the tolerance and disposition of ochratoxin A in young calves.

Tolerance to and disposition of ochratoxin A (OA) were compared in preruminant and ruminant calves. Two preruminant calves receiving 4.0 mg OA/kg body weight by stomach tube died; one of two calves receiving 1.0 mg/kg body weight survived. At a dose of .5 mg OA/kg body weight both calves survived. The administered OA was converted mainly (80.1 to 88.9%) to ochratoxin-alpha (O alpha), which was found only in urine; the remaining OA appeared in the urine (3.2 to 3.3%) and feces (7.8 to 10.0%). In the one surviving calf of two given .25 mg OA/kg body weight i.v., nearly twice as much OA was excreted in the feces (44.5%) as in the urine (25.0%); no O alpha was found in urine or feces. All four calves with functional rumens receiving OA orally, 2.0 mg/kg body weight, survived without overt ill effects. Approximately 90% of the OA was excreted as O alpha, with approximately four to eight times more in the urine than in the feces; OA was low in the urine or feces. A plot of the serum OA concentration-time data revealed a prominent, sustained, secondary peak, which was described adequately by a four-exponential equation with two apparent absorption components. Accordingly, OA initially was absorbed rapidly by a first-order rate process (ka = .496/h), and following a considerable delay (tlag = 12.84 h) absorption appeared to resume by a second, slower, first-order rate process (ka = .127/h). The second absorption phase was best explained as being due to enterohepatic cycling of OA.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1988

Ochratoxin A in blood from slaughter pigs in western Canada.

Twelve hundred blood samples were obtained in 1986 from pigs slaughtered in western Canada. The samples were assayed for ochratoxin as it is a potential contaminant in the food system. Blood ochratoxin concentration is a good indicator of tissue concentrations, particularly those in the liver and kidney. High performance liquid chromatography analysis of serum for ochratoxin demonstrated that 3.6 and 4.2% of the blood samples collected in February and March (n = 194) and May, June and July (n = 1006), respectively, had ochratoxin concentrations that exceeded 20 ng/mL. Overall the percent of samples that had concentrations of greater than 10, 20, 50, 100 and 200 ng/mL serum were 11.3, 4.1, 1.25, 0.42 and 0.08%, respectively. Samples that had ochratoxin concentrations that were greater than 20 ng/mL of serum were confirmed using two independent methods: liquid chromatography-mass spectrometry analysis and methyl ester derivatization followed by high performance liquid chromatography analysis.

Animals↗
PubMed1987

Mycotoxin formation in moist 2-row and 6-row barley during granary storage.

Eleven-kilogram parcels of 2-row and 6-row barley initially at 18% moisture content were implanted in dry bulk oats in a farm granary in Manitoba for 60 weeks between August 1983 and October 1984. Temperature, moisture content, O2 and CO2 levels, fat acidity values, seed germination, microfloral incidence and abundance and the presence of major mycotoxins (aflatoxins, sterigmatocystin, ochratoxin A, citrinin, penicillinic acid, patulin) were monitored. Ochratoxin A reached maximum levels of 0.97 ppm by week 24 in the 6-row barley, and 0.05 ppm by week 28 in the 2-row; no other mycotoxins were detected. The effect of cultivar type was significant (P less than 0.01) with greater effects in the 6-row barley for the following parameters: fat acidity value, germination, incidence of Alternaria alternata, Penicillium spp. and Helminthosporium sativum, total fungal propagule count and ochratoxin A levels. The effect of time was significant (P less than 0.05) for all variables except oxygen, carbon dioxide, Aspergillus versicolor, and total fungal propagule count. The interaction between cultivar and time was significant (P less than 0.01) for Alternaria and Helminthosporium only.

Alternaria↗
PubMed1985

Uveal melanoma presenting after cataract extraction with intraocular lens implantation.

Four patients underwent cataract extraction with implantation of intraocular lenses. Preoperative ultrasonography did not include a comprehensive diagnostic B-scan analysis. Postoperative examination revealed uveal melanomas. The clinical presentations as well as the histopathologic findings of the two enucleated eyes are discussed. These cases emphasize the necessity for B-scan ultrasonography prior to cataract surgery when media opacity prevents adequate visualization of the fundus.

Aged↗
PubMed1978

Increased aqueous lactate dehydrogenase in Coats' disease.

A 3-year-old boy had glaucoma and a total left retinal detachment that displayed peripheral intraretinal telangiectasis. The most probable clinical diagnosis was Coats' disease. A suspicion of retinoblastoma also existed, and an aqueous aspirate was assayed for lactate dehydrogenase (LDH) and found to contain three times the level present in a matching sample of serum. We enucleated the eye and verified the diagnosis of Coats' disease pathologically. The results of aqueous LDH determinations in eyes with glaucoma, phthisis, or large numbers of histiocytes, erythrocytes, and polymorphonuclear leukocytes should be interpreted with caution.

Aqueous Humor↗
PubMed1977

Postnatal triiodothyronine concentrations in healthy preterm infants and in infants with respiratory distress syndrome.

Postnatal changes in triiodotyronine (T3) concentration were investigated in 12 preterm infants of 26-34 weeks of gestational age. Blood for measurement of T3 was obtained from the cord at delivery and from infants at 1 day of age and at weekly intervals for 4 weeks. Seven of the babies suffered from respiratory distress syndrome (RDS) and five were considred healthy. Gestational ages and body weight were comparable in both groups. In preterm infants with RDS, cord blood T3 concentration was significantly lower than that in cord blood of babies without RDS (22 +/- 2.6 versus 36 +/- 5 ng/dl, P less than 0.05). There was no significant rise in T3 concentration of RDS babies at 24 hr of age (22 +/- 2.6 versus 34.0 +/- 8 ng/dl, P greater than 0.05), and hypotriiodothyroninemia persisted for 3 weeks. At 4 weeks of age, T3 concentration in babies with RDS, although within the normal range (80-190 ng/dl), was significantly lower than that in the healthy preterm infants (110 +/- 10 versus 165 +/- 11 ng/dl, P less than 0.05). Postnatal T3 changes in healthy preterm infants wre characterized by the absence of the initial hypertriiodothyroninemia and by a gradual rise within the first month of life. The noted difference in the pattern of postnatal T3 changes in healthy preterm infants compared to full term infants may reflect thyroid immaturity. The machanism and the significance of the neonatal hypotriiodothyroninemia in RDS and its long term effects on the development of these babies remain to be investigated.

Body Weight↗
PubMedDate not supplied

Chromatography of mycotoxins on precoated reverse-phase thin-layer plates.

Reverse-phase thin-layer chromatography of 18 common mycotoxins was carried out on Merck C18 and Whatman C18 and diphenyl bonded phases. The mobile phases included neutral and acidified binary mixtures of water and methanol, acetonitrile or tetrahydrofuran. Mycotoxins studied included aflatoxins B1, B2, G1, G2, sterigmatocystin, ochratoxin A, citrinin, penicillic acid, patulin, zearalenone, and the trichothecenes diacetoxyscirpenol, HT-2 toxin, nivalenol, neosolaniol, fusarenone-X, T-2 toxin, deoxynivalenol and 3-acetyl-deoxynivalenol. Both C18-bonded phases performed well, and could serve as a convenient confirmation for mycotoxins appearing in normal-phase (silica) thin-layer chromatographic screening procedures.

Chromatography, Thin Layer↗
PubMedDate not supplied

Organ weights, liver constituents, and serum components in growing chicks fed ochratoxin A.

Chicks were fed diets containing 0, 1, 5 and 10 mg/kg ochratoxin A (OA) over a four-week period to study the effects of OA on growth, weight of internal organs, liver RNA, DNA, protein, and glycogen and serum enzymes. Ochratoxin A depressed the rate of growth and relative weight of the bursa of Fabricius, and increased the relative weights of the liver, kidney, pancreas, and various sections of the gastrointestinal tract, but had no effect on the heart and spleen. Concentrations of liver RNA, DNA and protein were decreased while glycogen was increased. Serum alkaline phosphatase and gamma-glutamyl transferase activities, and uric acid and creatinine concentrations were elevated while serum proteins, albumin, phosphorus, potassium, and cholesterol were depressed. The effects of OA were time- and dose-dependent.

Animal Feed↗