The self determinants recognized by human virus-immune T cells can be distinguished from the serologically defined HLA antigens

The self specificity of human influenza virus-immune cytotoxic T cells has been analyzed in order to clarify the relationship between the self antigens that they recognize and the serologically defined HLA-A and -B antigens. Virus-immune effectors from HLA-A2-positive donors were tested on panels of virus-infected target cells from donors who were either HLA-mismatched or matched only for HLA-A2. Virus-immune T cells from 11 out of 11 A2-positive donors lysed all A2-matched virus-infected target cells (and no HLA-mismatched targets), except that each of these effector cells consistently failed to lyse virus-infected target cells from one A2-positive donor (designated M7). Although the A2 specificity of donor M7 could also be distinguished from the A2 antigen of other donors by alloimmune cytotoxic T cells, no differences in the A2 antigen of donor M7 could be defined by extensive serologic analyses. These results indicate that there is a strong but incomplete association between a self antigen recognized by virus-immune T cells and the serologically defined HLA-A2 specificity.     

Congenital dyserytropoietic anaemia, type II (HEMPAS) in three siblings

These siblings of a Czech family aged 21, 19 and 6 years, respectively, with congenital dyserythropoietic anemia, type II, (HEMPAS) are reported. In two elder siblings ferrokinetic studies revealed a rapid plasma 59Fe clearance, markedly decreased erythrocyte incorporation and shortened 51Cr red-cell survival. Direct anti-globulin test was found positive in one of them. Further investigations revealed low values of blood plasma cholesterol, total lipids, beta-lipoproteins, beta-carotine and vitamin E and A as well as low values of the prothrombin complex. Liver biopsy demonstrated siderosis and disseminated intravascular coagulation in the liver in both patients. The possible reasons for these humoral aberrations are discussed.     

The interpretation of a moving retinal image

It is shown that from a monocular view of a rigid, textured, curved surface it is possible, in principle, to determine the gradient of the surface at any point, and the motion of the eye relative to it, from the velocity field of the changing retinal image, and its first and second spatial derivatives. The relevant equations are redundant, thus providing a test of the rigidity assumption. They involve, among other observable quantities, the components of shear of the retinal velocity field, suggesting that the visual system may possess specialized channels for computing these components.     

Localization of ribosomal genes and nucleolar activity in lymphocytes of swine (Sus scrofa domestica) stimulated by phytohemagglutinins

The Pig chromosomes that contain rDNA sites displayed a polymorphism in the distribution of the genes among the nucleolar organizers located on pairs Nos. 8 and 10. Two, or more often three, active sites were observed in the chromosomes of lymphocytes stimulated with phytohemagglutinin. Only 5% of the metaphases showed a 4th small active site. At the onset of stimulation most cells contained one-two nucleoli; four nucleoli were never observed. After prolonged stimulation, the number of nuclei containing three nucleoli increased. A 4th small nucleolus appeared in a few cells, presumably formed by activation of the smallest rDNA site.     

Substratum topography and cell traction on sulphuric acid treated bacteriological-grade plastic

Treatment of bacteriological-grade plastic with concentrated sulphuric acid is a well known technique which increases the wettability of the surface and renders it suitable for eukaryotic cell adhesion. We have noticed that these substrata present a distinctive surface topography in the presence of a serum supplement under normal culture conditions. The adsorbed serum layer is comprised of fine furrows and ridges and the influence of adherent cells on this layer leads to minute tears and distortions in the direction of the corrugations. This provides a novel system for the investigation of cell spreading and locomotion by scanning electron microscopy.     

Fungal populations of the haulm base of wheat

Abstract In a 2-year field survey, the phylloplane mycoflora on the haulm base of wheat was studied by the dilution plate technique. No significant colonisation was registered before the end of May. Cladosporium spp., 'white' and 'red' yeasts were found to be the most abundant fungi.     

Inhibition of protein and lipid synthesis in muscle by 2,4-dinitrofluorobenzene, an inhibitor of creatine phosphokinase

A photoaffinity label, 4-azidobenzoyltrimethionine has been synthesized. It competitively inhibits trimethionine uptake in the yeast C. albicans. Upon UV irradiation it irreversibly and specifically blocks oligopeptide uptake. These results give the first example of photoinhibition of peptide uptake in yeast.     

Structure-activity relations of the molluscan neuropeptide FMRFamide on some molluscan muscles

Analogs of the molluscan neuropeptide FMRFamide were tested on four different molluscan muscle preparations which show qualitatively different responses to the peptide; the structure-activity relations are basically similar, but not identical. The C-terminal amide and the Arg³ residue are critical for FMRFamide-like activity on all four preparations. In contrast, analogs extended at the N-terminal or with conservative substitutions for the Phe¹ or Met² residue are approximately equipotent to FMRFamide. These structural requirements parallel those for the C-terminal tetrapeptide amide of gastrin.