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Biomedical subjects

I Brandt

Publications and source records attributed to I Brandt.

At least 73 records · Page 4Linked to original sources
PubMed1987

Metachromasia of 3-amino-9-ethylcarbazole (AEC) and its prevention in immunoperoxidase techniques.

3-Amino-9-ethylcarbazole (AEC) used as chromogen in immunoperoxidase techniques normally has an intense, red colour. However, as an inconstant phenomenon, a pale yellowish-green reaction product severely impairing the evaluation can be observed. In order to circumvent this undesired effect, factors such as tissue fixative, proteolytic digestion, antibody concentrations and incubation time of the primary antibody were analyzed. The most important factor inducing a change in colour is probably the inadequately high local peroxidase concentration arising as the consequence of high amounts of bound primary antibody. This high enzyme concentration might cause metachromasia of AEC by producing the yellowish-green quinone-di-imine form of the substrate. As could be shown by spectrophotometry in test tube experiments, AEC metachromasia was proven to be enzyme dependent. Thus, the best way to trigger the local enzyme concentration on a tissue section to adequate levels appears to be the dilution of the primary antibody.

Carbazoles↗
PubMed1987

Epithelial binding of hexachlorocyclohexanes in the respiratory and upper alimentary tracts: a comparison between the alpha-, beta- and gamma-isomers in mice.

The tissue distribution of the alpha-, beta- and gamma-isomers of 14C-labelled hexachlorocyclohexane (HCH) in pregnant mice was studied by whole-body and light microscopic autoradiography. The results showed that alpha-, beta- and gamma-HCH are taken up and retained in adult and foetal surface epithelia to varying degrees. Autoradiography of organic-solvent extracted tissue sections of nonpregnant mice given gamma-HCH (lindane) demonstrated that a high level of tissue-bound radioactivity was present in the tracheobronchial epithelium, the subepithelial glands in the olfactory mucosa, the squamous epithelia of the tongue, oesophagus, forestomach and vagina, the inner zone of the adrenal cortex, and the liver. Autoradiography of freeze-dried sections of pregnant mice given alpha- or beta-HCH showed preferential localization of radioactivity in the nasal and tracheobronchial epithelia after administration of both isomers, whereas localization of radioactivity in the epithelia of the tongue and oesophagus was only observed after administration of alpha-HCH. The results suggest that the localization of HCH isomers and/or their metabolites in the epithelial linings is regulated by factors that are highly substrate specific.

Animals↗
PubMed1987

Tissue binding of 1,2-dibromoethane in the cynomolgus monkey (Macaca fascicularis).

Autoradiography at different levels of resolution was used to study the tissue-binding of 1,2-dibromo[14C]ethane (DBE) in the cynomolgus monkey (Macaca fascicularis) in vivo (i.p. injection) and in vitro. The results show that DBE is metabolized to products which become bound to the tissues, preferentially in the liver and the kidney tubules. A distinct binding of radioactivity was also found in the adrenal zona reticularis. The binding of radioactivity in the surface epithelia of the respiratory and upper alimentary tract was not as high and striking as that previously observed in rodents. The results show that the sites of tissue-binding of DBE in the cynomolgus monkey correspond to the sites of tissue lesion observed in humans poisoned with DBE.

Animals↗
PubMed1987

Binding of the aliphatic halides 1,2-dibromoethane and chloroform in the rodent vaginal epithelium.

Whole-body and light microscopic autoradiography were used to study the binding of 1,2-dibromo(14C)ethane (14C-DBE) and 14C-chloroform (14C-CF) in the mouse and rat vaginal epithelium in vitro and in vivo. In pregnant mice, mice pretreated with pregnant mare's serum gonadotropin (PMSG) or ovariectomized mice primed with medroxyprogesterone, a high level of bound 14C-DBE metabolites were present in the epithelium, while in ovariectomized oestradiol-primed mice or intact oestradiol-primed mice, the binding was low. Similar results were obtained with 14C-CF, although the level of binding generally was lower than that observed after 14C-DBE-exposure. No binding of 14C-DBE-metabolites was observed in the juvenile rat vaginal epithelium, whereas a high binding was present in the PMSG-primed adult rat vaginal epithelium. Collectively, these data show that 14C-DBE and 14C-CF are transformed in situ to metabolites that are irreversibly bound to the vaginal epithelium. The results also suggest that the activating enzyme is under endocrine control and has a low activity in the juvenile and oestradiol-primed adult animal.

Animals↗
PubMed1987

3,3'4,4'-Tetrachlorobiphenyl in pregnant mice: embryotoxicity, teratogenicity, and toxic effects on the cultured embryonic thymus.

3,3',4,4'-Tetrachlorobiphenyl (TCB) is a known ligand of the Ah-receptor. When TCB was given to Ah-responsive C57BL/6 mice at gestation day 11, 12 or 13, a pattern of embryotoxic effects similar to those of TCDD was produced. This pattern included death and resorptions of the conceptus (peak sensitivity at day 11), as well as characteristic malformations such as cleft palate, dilated kidney pelvis (peak sensitivity day 12), and thymus hypoplasia (peak sensitivity day 13). The ED50 for cleft palate induction was found to be about 100 mg/kg, as compared to 30 micrograms/kg for TCDD (earlier results). The binding affinity of TCB for the Ah-receptor has been reported to be two orders of magnitude lower than that of TCDD. When TCB was introduced into a thymus organ culture (thymi taken from day-14 embryos), the lymphoid cell development was inhibited with an approximate EC50 of 5 X 10(-8) M. This is approximately 100 times higher than that of TCDD and in good agreement with the receptor binding affinities of both compounds. The difference in in vivo toxicity between TCB and TCDD can be explained by a more rapid metabolism and excretion of TCB.

Administration, Oral↗
PubMed1987

Metabolism of 2,3,4',6-tetrachlorobiphenyl: formation and tissue localization of mercapturic acid pathway metabolites in mice.

2,3,4',6-Tetrachlorobiphenyl (tetraCB) and the corresponding 14C-labelled compound (14C-tetraCB) were synthesized. Two reference compounds, 4-methylthio- and 4-methylsulphonyl-2,3,4',6-tetrachlorobiphenyl were also prepared and characterized. TetraCB and 35S-cysteine were given to groups of female mice. Formation of methyl[35S]sulphonyl-tetraCB was indicated by the presence of extractable sulphuric acid-soluble radioactivity in lung, liver, kidney and fat of the tetraCB-treated mice. As demonstrated by gel permeation chromatography followed by gas chromatography-mass spectrometry, the tissues of the tetraCB-treated mice contained mainly methylsulphonyl-tetraCB, minor amounts of tetraCB and traces of methylthiotetraCB. The major compound present in lung was 4-methylsulphonyl-tetraCB, indicating the presence of specific binding sites for this metabolite in lung tissue. According to autoradiography of mice injected with 14C-tetraCB, these binding sites were present mainly in the tracheo-bronchial mucosa.

Acetylcysteine↗
PubMed1986

Differences in marker expression among branched histiocytic cells in T-cell areas of the lymphoreticular system and among their epidermis- and mucosa-associated equivalents.

Branched histiocytic cells of the epidermis, the oral and anal mucosa, the tonsillar crypt epithelium, the thymus and of the T-cell-dependent areas of lymph node, spleen, and tonsil were examined with immunohistochemical single- and double-staining techniques. The markers used were a monoclonal anti-T6-antibody, a monoclonal anti-HLA-DR-antibody, heteroantiserum to S-100 protein and peanut agglutinin. Anti-HLA-DR and peanut agglutinin reacted with a considerable number of branched histiocytic cells, whereas anti-T6 and anti-S-100 protein only stained relatively small subpopulations. Concerning the population of branched histiocytic cells, double-staining revealed that the tissue distributions of all the markers used overlapped each other to various degrees; this was demonstrated by the different numbers of double-stained cells obtained in the experiments using all six possible combinations of primary reagents. The number of branched histiocytic cells co-expressing the markers varied depending upon marker combinations, types of tissue and microenvironment. We suggest that much of the immunologic phenotype of branched histiocytic cells is dynamic rather than static.

Anal Canal↗
PubMed1986

The tissue localization of m-AMSA and its effect on thymidine incorporation in various tissues in vivo.

The distribution of 14C-labelled m-AMSA was studied in rats and pigmented mice using whole body autoradiography. The agent rapidly disappeared from the blood, accumulating in significant amounts in large parenchymal organs, certain endocrine tissues, and the retina of the pigmented mouse eye. The hemopoietic and lymphoid tissues showed a moderate uptake of radioactivity with the highest concentration observed in the thymus. The autoradiograms indicated a rapid excretion of radioactivity via the liver, kidney and the glandular part of the gastric mucosa. The distribution pattern of label from 14C-m-AMSA remained unaffected by pretreatment of animals with high dose (500 mg kg-1 b.w.) of cytosine arabinoside. Injection of unlabelled m-AMSA (7 mg kg-1 b.w.) to growing rats 24 h before sacrifice resulted in a highly significant (P less than 0.001) inhibition of 3H-thymidine incorporation into the DNA of thymus and spleen. A less pronounced reduction was observed in the kidney, adrenal, lung and testes. The thymidine incorporation into the DNA of bone marrow was markedly suppressed when calculated per dry weight, but increased when related to the DNA content, suggesting early regeneration of the remaining cells. In contrast, no significant effects were observed on the DNA synthesis in small intestine and liver.

Aminoacridines↗
PubMed1986

o,p'-DDD in the mouse lung: selective uptake, covalent binding and effect on drug metabolism.

By means of autoradiography a high and selective accumulation was observed in the lung alveolar region of C57Bl mice injected with o,p'-[14C]DDD. Exhaustive extraction of lung tissue showed that a large fraction of the radioactivity was covalently bound to protein. Covalent binding in liver was 20-30 times lower and represented a smaller fraction of the total radioactivity present in this tissue. Formation of a cytochrome P-450 catalysed reactive metabolite in lung and liver was indicated by a decreased covalent binding in these tissues in mice pretreated with metyrapone. Both beta-naphthoflavone (beta NF) and phenobarbital (PB) pretreatment decreased binding of o,p'-DDD in lung tissue, while binding in the liver was induced by PB but remained unaffected by beta NF. Pretreatment with high doses of o,p'-DDD and p,p'-DDT gave a significantly decreased binding of o,p'-[14C]DDD in lung, whereas binding in liver remained unchanged. Conjugation with glutathione does not appear to be a major inactivation pathway for the reactive lung metabolite, since a high dose of o,p'-DDD did not deplete non-protein thiols (NPSH) in lung tissue. Pretreatment with o,p'-DDD decreased the N-demethylation of [dimethyl-14C]aminopyrine in both lung and liver in a dose-dependent manner, suggesting that the drug-metabolizing enzyme system may be a target for o,p'-DDD in vivo.

Adipose Tissue↗
PubMed1986

Effects of carcinogenic halogenated aliphatic hydrocarbons on [3H]thymidine incorporation into various organs of the mouse. A comparison between 1,2-dibromoethane and 1,2-dichloroethane.

The effects of 1,2-dibromoethane (DBE) and 1,2-dichloroethane (DCE) on the incorporation of [3H]thymidine into DNA were evaluated in various tissues of mice. The compounds were given intraperitoneally 24 h before sacrifice in an equimolar dose (293 mumoles/kg body weight). 2 h before the animals were killed, 0.5 mu Ci [3H]thymidine/g body weight was injected intraperitoneally. Both agents inhibited the [3H]thymidine incorporation in the forestomach, a site for their carcinogenic action. Whereas DBE also suppressed the [3H]thymidine incorporation in the nasal mucosa, the thymus, and the "glandular stomach", DCE was inhibitory only in the kidney. The observed difference in the effect of DBE and DCE on the thymus had its counterpart in a DBE-induced decrease of acid-insoluble radioactivity, demonstrated with whole-body autoradiography. The results indicate that in vivo screening of [3H]thymidine incorporation into various organs of an intact experimental animal is a sensitive technique for comparing cyto- and/or genotoxic effects of chemicals with a similar chemical structure.

Animals↗
PubMed1986

Decreased pulmonary drug metabolism in mice treated with the PCB metabolite 4-methylsulphonyl-2,2',5,5'-tetrachlorobiphenyl.

4-Methylsulphonyl-2,2',5,5'-tetrachlorobiphenyl (4-MeSO2-TCB) is a major polychlorinated biphenyl (PCB) metabolite present in lung tissue of PCB-exposed human subjects. After treatment of mice with 4-MeSO2-TCB (100 mg/kg), the pulmonary N-demethylation of aminopyrine in vitro was significantly decreased, while hepatic N-demethylation was concomitantly increased, as compared to tissue from control mice. Treatment of mice with 4-MeSO2-TCB also decreased the in vivo pulmonary covalent binding of o,p'-DDD, while the in vivo hepatic covalent binding was increased. The results indicate that 4-MeSO2-TCB inhibits or represses a cytochrome P-450-dependent enzyme activity in the mouse lung, while in contrast this activity is induced in the mouse liver.

Aminopyrine↗
PubMed1986

Fetal epithelial binding of 1,2-dibromoethane in mice.

Whole-body autoradiography and computer-assisted image analysis were used to study the tissue binding of the volatile carcinogenic pesticide 1,2-dibromo[14C]ethane (DBE) in C57BL mouse fetuses. Autoradiograms obtained from pregnant mice in late gestation (day 16-17), showed a high level of non-volatile metabolites in the epithelia of the fetal upper alimentary tract and respiratory tract. As determined by image analysis, the concentration of non-extractable (presumably covalently bound) metabolites in the oral epithelium was three times higher than in the maternal liver (day 17). The concentrations in the junction region of the forestomach and the mucosa of the nasal cavity were equal to that in the maternal liver, whereas the bronchi contained lower levels of non-extractable metabolites than the maternal liver. Autoradiography of excised fetal tissues incubated with DBE showed that high levels of non-extractable metabolites were present in the epithelia of the oral cavity, oesophagus and forestomach also in vitro. The results indicate that the fetal epithelia can activate DBE to products that bind to the tissue; they also raise the possibility that DBE is a transplacental carcinogen in mice.

Animals↗
PubMed1986

O-dealkylation of phenacetin in the olfactory rosette in rainbow trout (Salmo gairdneri).

Olfactory rosettes from trout (Salmo gairdneri) were found to metabolise (14C-ethyl)-phenacetin to 14CO2 in vitro. Based on wet weight, the rate of metabolism was lower than that in liver and gills. Based on protein content, the rate of metabolism was about equal to that in liver and gills. Addition of the cytochrome P-450 inhibitors metyrapone, 9-hydroxyellipticine and piperonyl butoxide significantly decreased the formation of 14CO2 from (14C-ethyl)-phenacetin in olfactory rosettes. Microautoradiography of rosettes incubated with (14C-ethyl)-phenacetin showed the presence of non-extractable metabolites in the sensory and indifferent epithelium. Addition of metyrapone decreased the binding of radioactivity in the epithelia considerably. When olfactory rosettes were incubated with (14C-dimethylamine)-aminopyrine, no formation of 14CO2 was observed. The results are concluded to indicate that cytochrome P-450 dependent enzyme activity is present in the epithelia of the trout olfactory rosette.

Aminopyrine↗
PubMed1986

3,3',4,4'-tetrachloro[14C]biphenyl in pregnant mice: enrichment of phenol and methyl sulphone metabolites in late gestational fetuses.

The distribution of radioactivity after injection of 3,3',4,4'-tetrachloro[14C]biphenyl (14C-TCB) in pregnant mice was determined by autoradiography and computer-assisted densitometric analysis. TCB metabolites in fetal tissue were analysed by g.l.c. and g.l.c.-mass spectrometry and compared to the synthesized reference compounds 2-, 5- and 6-methoxy-3,3',4,4'-tetrachlorobiphenyl. The concentration of radioactivity was high in the uterine fluid, and in the fetuses in late gestation. Fetal radioactivity decreased after pretreatment with a high dose of unlabelled TCB. Radioactivity was reversibly bound to fetal tissues. A phenolic metabolite, 3,3',4,4'-tetrachloro-2-biphenylol, and a methylsulphonyl-tetrachlorobiphenyl were found in fetuses in late gestation. No unmetabolized TCB was detected in the fetuses.

Animals↗
PubMed1985

Pitfalls in the interpretation of whole-body autoradiograms: long-time retention in brain and adrenal cortex caused by metabolic incorporation of 14C from various labelled xenobiotics.

The long-time retention of radioactivity in mice was studied by whole-body autoradiography after administration of 1-14C-alkanes (C12 and C16), 1-14C-polychlorododecanes (56 and 68% Cl w/w), U-14C-polychlorohexadecane (23% Cl w/w), ethyl-14C-phenacetin and ring-3H-phenacetin. All the labelled xenobiotics, except the high-chlorinated (68% Cl) polychloroalkane and the ring-3H-phenacetin, gave rise to long-time (12-60 days) retention of radioactivity in the central nervous system and in the adrenal cortex; the distribution of radioactivity within the brain corresponded to the stain intensity of myelin stained sections. Administration of 1-14C-fatty acids (C12 and C16) and 1-14C-acetylcoenzyme A gave a similar distribution pattern. The lipophilic radioactivity in brain and adrenal tissue was extracted and separated with thin-layer chromatography. In the adrenal extracts, the label co-chromatography mainly with cholesteryl ester, and in the brain extracts with cholesterol and with more polar lipids (mainly phosphatidyl-choline and -ethanolamine). The brain homogenate contained a non-extracted, probably proteinaceous, residue, with comparably high radioactivity. The results show that several 14C-labelled xenobiotics which give long time retention of radioactivity in the adrenal cortex and brain, are degraded to intermediates with the possibility to become incorporated into endogenous substances. The high-chlorinated alkane (1) and ring-3H-phenacetin (2) did not give such long time retention due to its persistance towards degradation (1), and lack of labelling of the degradable part of the molecule (2). It is concluded that erroneous interpretations can be drawn from distribution studies if the routes of degradation and positions of label of the 14C-labelled compounds are not considered.

Adrenal Cortex↗
PubMed1985

Growth dynamics of low-birth-weight infants.

The growth of weight, length and head circumference of 65 appropriate for gestational age (AGA) preterm infants and 85 full term controls has been studied longitudinally, with emphasis on growth velocity in the perinatal period. In comparison growth patterns of 51 small for gestational age (SGA) preterm infants have been analysed with respect to catch-up growth in relation to feeding practices. Weight gain of the AGA preterm infants is retarded until the corrected age of two months; their length remains below that of full term controls up to 21 months on average. Head circumference growth however is similar to intrauterine standards and from term agrees with that of the full term controls. Growth velocity is very high in the perinatal period and in the first months after term and decreases rapidly thereafter.

Birth Weight↗