Biomedical subjects

B Brunck

Publications and source records attributed to B Brunck.

3 recordsLinked to original sources

PubMed1991

Acanthocyturia--a characteristic marker for glomerular bleeding.

Erythrocyte morphology by phase contrast microscopic examination (PCM) of the urine is widely employed in distinguishing glomerular from nonglomerular bleeding. The proposed percentages of dysmorphic red cells are significant for glomerular bleeding in the range of 10 to 80% in the literature, because there is no clear cut definition of "dysmorphism." In the present study midstream urine samples of 351 patients with hematuria (greater than 8 erythrocytes/microliters) and of 33 healthy controls were examined. The various dysmorphic red cells were analyzed by PCM according to a detailed hematological classification. Most of the dysmorphic red cells, such as echinocytes, anulocytes, ghost cells, schizocytes, stomatocytes, codocytes and knizocytes, occurred in glomerular or nonglomerular disease as well, and proved to be uncharacteristic for glomerular bleeding. In contrast, a unique red cell deformity, a ringform with vesicle-shaped protrusions (acanthocyte) closely correlated to glomerular disease. In biopsy proven glomerulonephritis acanthocytes comprised 12.4% of all excreted red cells, whereas in nonglomerular diseases or in healthy subjects acanthocytes were seen very rarely (less than 2%) or not at all. Acanthocyturia greater than or equal to 5% (of excreted red cells) was seen in 75 out of 143 patients with proven glomerulonephritis (sensitivity 52%) and in four out of 187 patients with nonglomerular disease (specificity 98%). To improve the diagnostic value of erythrocyte morphology the diagnostic workup should focus on acanthocyturia, which is also indicative in very low erythrocyte counts.

Acanthocytes↗

PubMed1988

Bioavailability of soil-bound TCDD: oral bioavailability in the rat.

The implications to the public health of trace amounts of 2,3,7,8-TCDD in the environment are under evaluation by regulatory agencies in the United States and Western Europe. One major consideration in such evaluations is the contribution to human exposure via ingestion of TCDD-contaminated soil. An 80% figure is under consideration by some regulators for estimated human exposure. A contractor for one agency has, in fact, used a value of 100% bioavailability for estimating human bioavailability. Several studies have investigated the oral bioavailability of TCDD from contaminated soil in animals. Most have reported estimates of 25-50%, although one has reported less than 0.5 and 85%, depending on the source of the contaminated soil. This paper reports an oral bioavailability of approximately 43% in the rat dosed with three environmentally contaminated soil samples from Times Beach, Missouri. This figure did not change significantly over a 500-fold dose range of 2 to 1450 ng TCDD/kg of body weight for soil contaminated with approximately 2, 30, or 600 ppb of TCDD. The relevance of animal oral bioavailability data for the human remains to be evaluated. However, since regulatory agencies use animal data for extrapolating to humans, the 43% or 25-50% figure would be more accurate than the 80 or 100% estimates.

Administration, Oral↗

PubMed1988

Bioavailability of soil-bound TCDD: dermal bioavailability in the rat.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), an unwanted by-product formed during the manufacture of hexachlorophene and phenoxyherbicides, has been found as an environmental contaminant in many U.S. and Western European sites. This study examines in the rat the degree of dermal absorption of TCDD bound to soil. Such information would assist regulatory agencies in evaluating the degree of exposure of humans who come in contact with TCDD-contaminated soil. Several parameters which may influence dermal absorption were studied, including TCDD dose, duration of contact, presence of crankcase oil as a co-contaminant, and environmentally contaminated vs laboratory-prepared soil. The dermal penetration of TCDD following 4 hr of contact with skin was approximately 60% of that following 24 hr of contact (P less than or equal to 0.05). Following 24 hr of contact with the skin, the degree of dermal uptake of TCDD contaminated soil was approximately 1% of the administered dose. Under the conditions of the present study, the degree of uptake does not appear to be influenced to any significant extent by the concentration of TCDD on soil, the presence of crankcase oil as co-contaminants, or by environmentally vs laboratory-contaminated soil. Although a number of parameters examined in this study did not significantly influence the degree of dermal absorption of TCDD in the rat following 24 hr of contact with the contaminated soil, the unqualified use of the 1% value to estimate human exposure would overestimate human exposure, since there is general agreement among researchers that rat skin tends to be more permeable than human skin to highly lipid-soluble compounds such as TCDD.

Animals↗