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Biomedical subjects

I Brandt

Publications and source records attributed to I Brandt.

At least 109 records · Page 6Linked to original sources
PubMed1981

[Head circumference and brain development. Growth retardation during intrauterine malnutrition and catch-up growth mechanisms (author's transl)].

Today the close correlation between head circumference growth and brain development in the last weeks of gestation and in the first two years of life is no longer disputed. A recently developed formula even allows for calculations of brain weight based upon head circumference data. Between the ages of 32 postmenstrual weeks and six months after expected date of delivery there is a period of very rapid brain growth in which the weight of the brain quadruples. During this growth spurt there exists an increased vulnerability by unfavorable environmental conditions, such as malnutrition and psychosocial deprivation. The erroneous belief still being prevalent that the brain of the fetus and young infant is spared by malnutrition, can be looked upon as disproved by new research results. Severe malnutrition during the brain growth spurt is thought to be a very important non-genetic factor influencing the development of the central nervous system (CNS) and therewith intellectual performance. In the past a permanent growth retardation of head circumference and a reduced intellectual capacity usually was observed in small-for-gestational age infants (SGA). Nowadays, however, there can be found also proofs of successful catch-up growth of head circumference and normal intellectual development after early and high-energy postnatal feeding of SGA infants. The development of SGA infants of even very low birth weight can be supported in such a way that it takes a normal course by providing good environmental conditions, such as appropriate nutrition - especially during the early growth period - and a stimulating environment with abundant attention by the mother.

Adolescent↗
PubMed1981

Bronchial mucosal and kidney cortex affinity of 4- and 4,4'-substituted sulphur-containing derivatives of 2,2'-5,5'-tetrachlorobiphenyl in mice.

In order to evaluate further the structural requirements previously proposed for accumulation of polychlorinated biphenyls (PCB) and their sulphur-containing metabolites in the respiratory tract of mice, 4-methylthio-, 4-methylsulphonyl and 4,4'-bis(methylthio)-2,2',5,5'-[14C] tetrachlorobiphenyl were studied by whole body autoradiography. All the compounds gave rise to a strong accumulation of radioactivity in the mucosa of the bronchi, trachea and larynx. The first two substances were also concentrated in the mucosa of the nasal cavities. At the longer post-injection times all the compounds studied were localized in distinct sites of the kidney cortex. However, while the uptake of the monosubstituted sulphur-containing tetrachlorobiphenyl metabolites there was comparatively weak, the bis(methylthio) derivative showed a remarkable accumulation and retention in the kidney cortex. The study makes it possible to formulate the structural requirements for bronchial accumulation on the basis of the structure of the compounds that are accumulated rather than on the structure of the unmetabolized polychlorobiphenyls. Also with regard to the uptake in the kidney cortex a specific structure-dependency seems to exist.

Animals↗
PubMed1981

Persistence of 2,3,6-substituted pentachlorobiphenyls in the lung parenchyma: a new structure-dependent tissue localization of polychlorinated biphenyls in mice.

Whole body autoradiograms of mice injected with 2,2',3,3',6-[14C]pentachlorobiphenyl (I), 2,3,3',4',6-[14C]pentachlorobiphenyl (II), 2,2',3,5',6-[14C]pentachlorobiphenyl (III) and 2,3',4,5,5'-[14C]pentachlorobiphenyl (IV) showed a specific accumulation of I-III in the lung parenchyma, whereas IV did not accumulate in the lung tissue. The results suggest that chlorobiphenyls with chlorine atoms in the positions 2,3,6 possess a specific affinity for the lung parenchyma. These chlorobiphenyls differ in chemical structure from those which are accumulated in the bronchial mucosa and those which are not taken up in the respiratory tract. The importance of in vivo metabolism in the determination of structure activity relationships is stressed.

Animals↗
PubMed1980

Selective binding of aldrin and dieldrin in cartilage.

Whole body autoradiography of 14C-aldrin and 14C-dieldrin in pregnant mice indicated a slow but persistent uptake of both substances in cartilage, e.g. in the vertebral and epiphyseal discs. Also in the fetal skeleton a marked accumulation was observed.

Aldrin↗
PubMed1980

Cysteine and methionine-precursors of methyl sulphone metabolites of 2,4',5-trichlorobiphenyl in mice.

In order to account for the origin of the sulphur atom in methyl sulphones derived from polychlorinated biphenyls (PCB), groups of mice were treated with 2,4'-5-trichlorobiphenyl and [35S]cysteine or [35S]methionine, respectively. Control animals received the labelled amino acids only. The radioactive substances extracted from lung tissue were characterized by partition between hexane and sulphuric acid, thin-layer radiochromatography (TLRC), gas chromatography (GC) and mass fragmentography (MF). In lung extracts of both experimental groups sulphuric acid soluble metabolites were present: Their Rf-values on TLRC were identifical with that of 4-methylsulphonyl-2,4'-5-trichlorobiphenyl and their identity was confirmed by GC and GC-MF, which also indicated the presence of a minor sulphone isomer. The study shows that both cysteine and methionine could function as donors of the sulphur atom in the methyl sulphone metabolites derived from PCB.

Animals↗
PubMed1976

[Distance and velocity standards for head circimference growth before and after term until 18 months--results from a longitudinal study (author's transl)].

Standards for head circumference growth (distance and velocity) from the perinatal period until the age of 18 months have been based on repeated measurements at short intervals (longitudinal) in 60 appropriate for gestational age (AGA) preterm infants of very low fetal age, and 68 full term infants. Moreover the growth of 32 small for gestational age (SGA) preterm infants has been evaluated. Before term the extrauterine head growth curve is similar to that of "intrauterine curves". At term and until the age of 18 months the growth curves of AGA preterm infants agree well with those of the full term controls, without statistically significant differences (p greater than 0.1). If the age is not corrected for prematurity ther is a significant difference between preterm and full term infants until 17 months (p less than 0.05). With decreasing velocity of head circumference growth this difference becomes non-significant at the age of 18 months (p greater than 0.1). Out of the heterogenious group of 32 SGA preterm infants 15 have shown a catch-up growth in head circumference until the third month, whereas 17 infants remained significantly below the growth curve of the AGA. Growth velocity of head circumference, calculated in cm/month, in the last 10 weeks before term is significantly higher (p less 0.025) than later on, with a mean peak of 4.3 cm in the 34th postmentstrual week. After term, the velocity curve of the AGA preterm infants agrees with that of the full term controls. A period of rapid head circumference growth -- a growth spurt -- extends from the 31st postmenstrual week until the 6th month after term. In the following months the velocity curves flatten. If the age is not corrected for prematurity, the peak of the velocity curve becomes flat and spread with a mean growth velocity of 3.0 cm in the first, of 3.4 cm in the second and of 2.5 cm in the third month.

Birth Weight↗
PubMed1975

Distribution of 2,2(1),4,4(1),5,5(1)-hexachlorobiphenyl in mice and Chinese hamsters: dose dependent accumulation in the mouse bronchial mucosa.

The distribution of 2,2(1),4,4(1),5,5(1)-hexachlorobiphenyl-14C was studied in mice and Chinese Hamsters using whole body autoradiography and liquid scintillation counting. The mice exhibited a strong and persistent accumulation of radioactivity in the bronchial mucosa, and this accumulation was not fully developed until about 24 hours after an intravenous injection. The labelled substance passed to the fetuses of pregnant mice and was also concentrated in the fetal bronchi. Mice pretreated with a large dose of unlabelled PCB per os in peanut oil showed a completely different distribution pattern in the lungs--only traces of label being taken up by the bronchi. Quantitative measurements revealed a concomitant reduction of the total radioactivity retained by the lungs. Except for the lungs, however, no major differences in the distribution pattern were found at the various dose levels. The distribution in the Chinese hamsters equaled approximately that of the mice, but a very weak accumulation of label was observed in the hamster bronchi. The radioactivity in the mouse bronchi was considered as perhaps representing metabolized PCB.

Adipose Tissue↗
PubMed1975

The distribution of 2,21,3,4,41,61, and 2,31, 4,41,51,6- hexachlorobiphenyl in mice studied by whole-body autoradiography.

The distribution of 14C-labelled hexachlorobiphenyl in male and pregnant female mice was studied by whole-body autoradiography and liquid scintillation counting. Shortly after an intravenous injection there was a strong uptake of polychlorinated biphenyl (PCB) in the corpora lutea, the adrenal cortex and the liver and radioactivity was retained fro a long time in these tissues. Even in the fetal adrenal cortex a considerable accumulation occurred. High activity was also present in the brown fat, the lung, the the myocardium, the gastric mucosa, the pituitary and the bone marrow. Radioactivity penetrated slowly to the brain and fetal tissues but the concentration remained consistently low. In the adipose tissues there was a gradual increase in radioactivity and the autoradiograms from the longer survival times were dominated by these sites. There was a continuous biliary excretion of labelled material to the small intestine; this occurred in the fetuses as well.

Animals↗