Size variation polymorphisms of the short arm of human acrocentric chromosomes determined by R-banding by fluorescence using acridine orange (RFA)

Summary One hundred normal Caucasians were studied by the RFA technique to estimate the frequencies of size variation of the short arm of acrocentric chromosomes. Each size variation was classified into one of five levels. The most frequent size level (code) was 3; therefore, this was regarded as the average size. If one excludes the average size, the frequencies of size variation by RFA for chromosome 13, 14, 15, 21, and 22 were 22.5, 19.5, 14.5, 19, and 17% respectively. There was no significant difference for the overall frequencies of size variation between sexes. Furthermore, the RFA technique detects more variation in the size of human acrocentric chromosomes than any other method.     

Light-scattering studies of bull spermatozoa. II. Interaction and concentration effects.

The complete autocorrelation function of the intensity fluctuations of laser light scattered from motile bull spermatozoa is shown to depend upon several factors not previously considered. Samples of bull spermatozoa generally contain a substantial proportion of dead cells, which give rise to slowly decaying components of the autocorrelation function. Whereas previous work has concentrated on the form of the fast decaying autocorrelation component, we are concerned here with the relative amplitude and shape of the slow autocorrelation component and the general form of the composite function. In principle, the relative amplitudes of the fast and slow components of the autocorrelation function can be used as an assay of the proportion of swimming cells. We show that this amplitude ratio depends upon cell concentration, scattering cell geometry, and scattering angle. A simple model is developed to explain these results on the basis of the asymmetry of light scattered from these cells, motile/immotile cell interactions, wall-swimming effects, and geotactic reorientation of dead cells.     

The Scyphomedusae of the Rockall Trough, northeastern Atlantic Ocean

An extensive series of samples between the surface and 2700m depth have been taken in the Rockall Trough between 1973 and1978. The coronate medusae, in decreasing order of abundanceoccurring in the Trough are: Periphylla periphylla, Atolla wyvillei,A. parva, A. vanhoeffeni and Nausitho? globifera. The last specieswas rare and no information on its biology was obtained. Theother species breed within the Trough, the three Atolla speciesthroughout the year. Few large mature Periphylla periphyllawere caught and its breeding season remains undefined. Theirmorphology and vertical and geographical distributions are brieflydiscussed. The semaeostomid medusae, Pelagia noctiluca, Aureliaaurita and Cyanea lamarckii also occurred, the latter two speciesconfined to the Rockall Bank.     

Altered processing of integrin receptors during keratinocyte activation

We used monoclonal antibodies against specific integrin subunits to examine the role of integrin receptors in keratinocyte activation. We found that before activation, beta 1 subunits in keratinocytes showed a diffuse distribution, whereas after activation, keratinocytes organized beta 1 receptors into marginal adhesion plaques. In immunoprecipitation experiments with antibodies against beta 1 integrin subunits, we found mostly immature subunits synthesized in keratinocytes freshly harvested from skin. Moreover, integrin receptor complexes immunoprecipitated from these cells by monoclonal antibodies against alpha 2, alpha 3, or alpha 5 subunits contained only immature beta 1 subunits. With keratinocytes cultured 4-7 days, anti-beta 1 antibodies immunoprecipitated mostly mature beta 1 subunits, and integrin complexes immunoprecipitated from cultured cells by anti-alpha subunit antibodies contained mostly mature beta 1 subunits. Antibodies directed against beta 1 subunits also inhibited keratinocyte migration. Based on these results, we suggest that up-regulation of migration by activated keratinocytes depends on changes in processing of pre-beta 1 subunits to mature beta 1 subunits. We also studied the distribution of integrin subunits in skin and on keratinocytes migrating out of skin explants. Whereas beta 1, alpha 2, and alpha 3 subunits were detected in keratinocytes in skin and migrating out of explants, alpha 5 subunits were observed only in migrating cells.     

Cerebral Metabolic Effects of Monoamine Oxidase Inhibition in Normal and 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine Acutely Treated Monkeys

The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induces dopaminergic cell death in the substantia nigra pars compacta (SNpc) and clinical parkinsonism in humans and experimental animals. Pretreatment with monoamine oxidase inhibitors prevents this cell death and associated parkinsonism by blocking the oxidation of MPTP to a toxic intermediate. The 2-deoxyglucose method was used to study the acute effects of MPTP in the monkey brain and the effects of monoamine oxidase inhibition on local cerebral glucose utilization in both normal and MPTP-treated monkeys. MPTP administration alone caused a major increase in glucose utilization in the SNpc and smaller increases in some subnuclei within the ventral tegmental area in which eventual dopaminergic cell loss also occurs. Pretreatment with pargyline abolished these metabolic increases, a finding suggesting both that the oxidized product of MPTP generates the metabolic increases and that the increased glucose consumption may contribute to cell toxicity. On the other hand, in most cortical, thalamic, striatal, brainstem, and cerebellar areas MPTP alone caused reductions in glucose utilization, and pargyline failed to prevent these effects. Pargyline alone depressed metabolism in the locus coeruleus and a few other monoaminergic structures.     

The snRNP E protein multigene family contains five pseudogenes with common mutations.

Sequence data from three previously-uncharacterized members of the snRNP E protein multigene family suggest that each is a non-transcribed processed pseudogene, even though one clone has the potential to code for a full-length protein with greater than 90% similarity to previously-characterized E protein cDNAs. Each of the newly-analyzed family members is without introns, contains a tract of polyadenylic acid residues, and is flanked by short direct repeats. In addition, the three sequences all contain point mutations that distinguish them from the E protein coding sequence. Seven point mutations are common to the three sequences described here and to two previously-described E protein pseudogenes. Although all of these mutations are transitions, only 5 of 7 could have been generated by deamination of methylated cytosines in inactive genes. Thus, the common mutations in the pseudogenes suggest an origin other than the expressed gene that we have described. Allelic variants for two of the pseudogenes were detected and repetitive elements are located near four of the five E protein pseudogenes that have been characterized.     

The rapid purification of 3-hydroxybutyrate dehydrogenase and malate dehydrogenase on triazine dye affinity matrices.

3-Hydroxybutyrate dehydrogenase (EC 1.1.1.30) and malate dehydrogenase (EC 1.1.1.37) were purified to homogeneity on a large scale involving only two sequential affinity-chromatography steps on two triazine dye-Sepharose matrices. Recoveries of both enzymes were in excess of 60%. Malate dehydrogenase could also be purified by a combination of triazine dye affinity chromatography and gel filtration on Ultrogel AcA-44, but this offered no significant advantage over the purely affinity procedure.     

Relation between diameter and flow in branches of the bronchial tree

Two methods are described for calculating the value of the exponentx in the equation flow =k×diameter ^x , as pertaining to a branch of the bronchial tree. In the lungs from three humans, two dogs, one hamster, and one rat mean values ofx between 2.419 and 2.903 were found. They lie within the range of 2.333 to 3.0 predicted by the analysis of Uylings (Bull. Math. Biol. 39, 501–519, 1977).