Incidence of chromosome abnormalities in newborn children. Comparison between incidences in 1969–1974 and 1980–1982 in the same area

Summary As part of an ongoing study of the influence of environmental factors on pregnancy, childbirth, and fetuses, comparisons have been made between incidences in 1969–1974 and in 1980–1982 of chromosome aberrations in liverborn children in the same area of Denmark. The incidence of chromosome aberrations in the first period was 2.6 per 1000, compared with 4.1 per 1000 during the latter period. However, the difference was mainly due to an increase in inversions, and this in turn was due to a difference in chromosome staining methods between the two periods.It is concluded that the Danish study and similar studies in the United States, Canada, and Scotland indicate that early detection of chromosome aberrations by chromosome examination at birth is indicated in order to be able to inform and counsel parents of children with chromosome aberrations. Chromosome examination at birth is also of importance in the diagnosis of structural inheritable chromosome aberrations and consequent family investigation and genetic counseling.     

Formation of (4R)- and (4S)-4-hydroxyochratoxin A from ochratoxin A by liver microsomes from various species.

Two metabolic products were formed from ochratoxin A by human, pig, and rat liver microsomal fractions in the presence of reduced nicotinamide adenine dinucleotide phosphate. They were isolated from the incubation mixture in the presence of pig liver microsomes by extraction, thin-layer chromatography, and high-pressure liquid chromatography Their structures are suggested to be (4R)- and (4S)-4-hydroxyochratoxin A on the basis of mass and nuclear magnetic resonance spectroscopy. Km and the maximum velocity for the formation of the two metabolites by human, pig, and rat microsomes were determined. Their formation was inhibited by carbon monoxide and metyrapone. The results indicate that the microsomal hydroxylation system is a cytochrome P-450 and that different species are involved in the formation of the two epimeric forms of 4-hydroxyochratoxin A.     

Resource partitioning between unionid mussels in a Swedish lake outlet

Partitioning of food and space resources of two dominating unionid mussel species, Anodonta piscinalis and Unio pictorum , was investigated in a South Swedish lake outlet. Differences in diurnal activities were not considered to be a mechanism for niche segregation. The two species ingested particles of almost identical size distribution indicating a high overlap in food. Mussel distribution was correlated to environmental variables including substrate properties, water depth, current velocity, and distance from the lake, the latter being a relative measure of food quality and quantity, U. pictorum dominated near the lake and in the centre of the river while A. piscinalis had its peak density ca. 500 m below the lake and was relatively more abundant along the river margins. At maximum mussel densities, which were found near the lake, a separation in space was more obvious than downstream, implying possible interspecific interactions.     

Rats chronically injected with urine from Huntington's chorea patients do not striatal damage

Rats were injected subcutaneously for 147 consecutive days with large volumes of urine from control subjects and from patients with Huntington's chorea (HC) in an effort to test for presence of a possible neurotoxic substance in HC. No evidence of illness was observed in animals treated with HC urine, and their behavior did not differ from animals treated with control urine. After rats were sacrificed, striatum was examined for the biochemical and neuropathological changes seen in human striatum in HC. No deficiency of γ-aminobutyric acid content, nor reduction in activities of glutamic acid decarboxylase and choline acetyltransferase, was found in striatum of rats chronically treated with HC urine. Also, no significant differences were found between striatum of control and experimental rats by light or electron microscopy. These results neither support for exclude the possibility of a neurotoxic mechanism for the neuronal loss characteristic of HC.     

Plasma and Tissue Levels of Trimethoprim in The Rainbow Trout,Salmo Gairdneri,After Absorption From Fresh and Salt Water

This is a comparative study of uptake of trimethoprim from 1) fresh water, 2) salt water after 7 days of adaption and 3) salt water without previous adaptation. The rate and extent of absorption were found to vary significantly. The salt water adapted group reached a plasma concentration of approx. 1 µg/ml after 10 h, the unadapted salt water group after 24 to 48 h and the fresh water group did not reach this concentration. The results are discussed in relation to the non-ionic diffusion theory and to the alterations taking place in euryhaline species of fish during adaptation to salt water.     

Total Thyroxine and Free Thyroxine Index in Plasma of Dairy Cows in Relation To Strength of Heat

Total thyroxine (TT4) and free thyroxine index (FT4I) were measured in peripheral plasma of cows. The samples were collected at the time of insemination from 66 cows showing pronounced signs of the heat and from 56 cows showing weak or silent heat. Neither TT4 or FT4I in plasma differed significantly between the two categories of oestrous cows.     

Abiotic formation of particles from extracellular organic carbon released by phytoplankton

¹⁴C-labeled extracellular organic carbon (EOC) released by the phytoplankton in a Danish Estuary was shown immediately to form particles (>0.2m) when the products were added to a natural water sample. About 14%–20% of the added activity could be recovered as particles. Any bacterial assimilation of the extracellular products was thus masked. The abiotic origin of the particulate EOC was verified, and it was shown that the particle formation was due to some factors present in the estuarine water with a nominal diameter >0.2m. Precaution must be taken to avoid misinterpretations in studies concerning carbon flow from algae to bacteria.     

Phosphorylation of lens membrane: identification of the catalytic subunit of Na+, K+-ATPase

Receptor mediated endocytosis appears to depend on the action of a transglutaminase (TGase). Endocytosis can be induced in intact human RBC by the action of several classes of drugs. We tested the hypothesis that drugs acted by stimulating TGase activity. Of the endocytosis inducing drugs tested, neither primaquine nor vinblastine nor chlorpromazine enhanced TGase activity. We next tested the hypothesis that TGase activity was required for drug endocytosis in RBC by adding known TGase inhibitors. Paradoxically, m-Dansyl cadaverine, the most potent TGase inhibitor, produces endocytosis in human RBC. Therefore despite apparent striking morphologic similarities, drug induced endocytosis in RBC appears to proceed via different mechanisms from those involved in receptor mediated endocytosis in other cells.In the receptor-mediated endocytosis of some hormones and growth factors, it appears that the receptor-ligand complex forms clusters over clathrin coated pits which are then internalized as endocytic vacuoles. Both the clustering and internalization of ligands are inhibited by a variety of agents shown to inhibit transglutaminase (TGase) and it is therefore proposed that TGase participates in receptor-mediated endocytosis (1–3). Human erythrocytes undergo endocytosis when exposed to drugs like primaquine, chlorpromazine, and vinblastine (4), all of which are amphipathic cations (4). However, the mechanism of drug action is not known nor is it clear that this is a form of receptor-mediated endocytosis (4). Furthermore, clustering of receptors can occur in neonatal but not adult human RBC (5). TGase has been measured in human red cells (6) although its physiologic role is unknown. Like all TGases, it is calcium dependent (6,7), and primaquine induced red cell endocytosis is enhanced by Ca⁺⁺ addition (8). Therefore, we tested the hypothesis that TGase participates in drug induced endocytosis in intact human red cells.