The low-frequency EEG component in the healthy subject and its changes as affected by acutely developing foci at the level of the diencephalon and brain stem structures

The data are given of the analysis of the low-frequency EEG component (LF EEG--0.2--2.0 Hz) of 34 healthy subjects and 36 patients examined in dynamics in the acute period after operations: ablation of a tumour localized at the level of the diencephalon and the level of the brainstem. The LF EEGs were analyzed by a special program: auto- and crosscorrelation functions and power spectra were estimated. In the norm LF EEGs were characterized by mosaics, various frequencies and periodicity in various cortical areas, they appeared with interhemispheric asymmetry, depended on the EEG type--dominance or lack of the alpha-rhythm. In patients in the post-operative period the LF EEGs were changed; in favourable terminations, at first the period of oscillations and the coefficient of correlation increased, then they tended to normalization. In unfavourable terminations, with gross pathological foci in these areas, the LF EEGs acquired a synchronized character, with a higher frequency than in the norm.     

The lateralization of hemispheric control over pain-induced vocalizations in rats

Study was carried out on 232 white rats, male and female, fixed in a hammock and subjected to painful stimulation of the tail. The first impulse of pain vocalization was analyzed. The rats were divided into three groups--with intact brain, with inactivated left or right hemisphere. The first impulses of rats pain vocalizations may be divided into short screams with 40-140 ms duration and long squeals of 140-420 ms duration. Unilateral cortex inactivation led to a reduction of the latency, increase of the peak amplitude and change of the per cent both of the pain screams and pain squeals. After elimination of the left hemisphere as compared with that of the right one, a shorter latency and a greater per cent of the pain screams was observed and a smaller per cent of pain squeals. The obtained data testify to the dominance of the left hemisphere in the control of pain vocalizations in rats.     

Monoclonal antibodies localize events in the folding, assembly, and intracellular transport of the influenza virus hemagglutinin glycoprotein

We used monoclonal antibodies that recognize monomeric and/or trimeric forms of the influenza virus hemagglutinin (HA) to study biosynthesis of this integral membrane protein in influenza virus-infected cells. We find the following: First, the globular head of the HA folds into its mature conformation in the endoplasmic reticulum prior to the assembly of HA monomers into trimers. Second, trimerization begins within 1 to 2 min following synthesis, with a half-time of approximately 5 min. Third, trimerization occurs only after the HA has been transported from the endoplasmic reticulum. Fourth, newly formed trimers are sensitive to acid-induced conformational alterations associated with viral fusion activity.     

A quantitative study of enterotoxin production by sheep milk staphylococci

Of 124 staphylococcal strains isolated from sheep milk, 78 produced enterotoxin A, B, C, or D when evaluated by an enzyme-linked immunosorbent assay. Enterotoxins A and D, elaborated by 44 and 43 strains, respectively, showed the highest incidence. Enterotoxin production by coagulase-negative strains (one Staphylococcus cohnii, three S. epidermidis, five S. haemolyticus, and four S. xylosus) was detected. Linear and logarithmic-logarithmic regressions of optical density on enterotoxin concentration yielded the best-fitting equations for enterotoxin quantitation. A significantly higher incidence of enterotoxin producers and significantly higher levels of enterotoxins produced were recorded for coagulase-positive, thermostable nuclease-positive, hemolysis-positive, or mannitol-positive strains. Mannitol utilization was the best test for discriminating between enterotoxigenic and nonenterotoxigenic staphylococci.     

Characteristics of rhamnan isolated from preparations of Pseudomonas aeruginosa lipopolysaccharides

A polysaccharide isolated from the degraded lipopolysaccharides of P. aeruginosa serogroup O7 (Lányi--Bergan classification) was characterized by liquid chromatography, acid hydrolysis, and 1H and 13C NMR spectroscopy. It has molecular mass 15,000 and represents mainly a rhamnan of the structure----2)-alpha-D-Rha-(1----3)-alpha-D-Rha-(1----3)-alpha-D-Rha-(1 ----, identical to the structure of O-specific polysaccharides of Pseudomonas aeruginosa pvs morsprunorum and cerasi. Some minor constituents, such as glucose, mannose, an unknown sugar, and phosphate, are found in the polysaccharide preparation as well. Distribution of the rhamnan in some other P. aeruginosa serogroups is discussed and its identity to the common polysaccharide antigen of P. aeruginosa is suggested.     

Model studies at mechanical aortic heart valve prostheses--Part I: Steady-state flow fields and pressure loss coefficients

In a 3:1 scaled model of the human aorta models of the Omniscience, Bj?rk-Shiley Convexo-Concave, Bj?rk-Shiley Monostrut, Medtronic-Hall, Duromedics (Hemex) and the Saint Jude Medical heart valve prostheses are studied in steady flow representing the systolic peak flow phase. Detailed flow visualization experiments show flow separations at all inner ring surfaces as well as at most of the occluders. The resulting stagnation areas increase the risk of thrombus accumulation. Flow separations also stimulate vortex formation and turbulent mixing at the downstream jet boundaries and thus may intensify blood damage by turbulent shear stresses. The different influences of struts and occluder guides on the flow around the occluders are discussed. The effects of the individual valve components on the flow fields are analyzed and correlated with the resulting pressure losses.     

Purification of the growth-related protein p25 of the Ehrlich ascites tumor and analysis of its isoforms

1. Two of the three isoforms of the growth-related protein p25 of the Ehrlich ascites tumor have been purified to homogeneity by giant two-dimensional polyacrylamide gel electrophoresis. 2. Antibodies raised against the isoform p25/1 react also with isoforms p25/2 and p25/3. 3. Limited tryptic digestion of p25/1 and p25/2 resulted in similar oligopeptide patterns. Corresponding oligopeptides of both isoforms have identical amino acid sequences. 4. The isoforms p25/2 and p25/3 are phosphorylated derivatives of unphosphorylated p25/1. The phosphorus is bound to serine and a further unknown phosphorylation site.     

Effect of metal ions on the fluorescence of leucine aminopeptidase and its dansyl-peptide substrates

The effect of Cu(II), Ni(II), Zn(II), Mg(II), and Mn(II) on the fluorescence of porcine kidney cytosol leucine aminopeptidase and three of its dansyl(Dns) peptide substrates, Leu-Gly-NHNH-Dns, Leu-Gly-NH(CH2)2NH-Dns, and Leu-Gly-NH(CH2)6NH-Dns, has been investigated. These five metal ions were chosen for study because each binds to the regulatory metal binding site of leucine aminopeptidase. Since the binding is relatively weak, kinetic studies of the different metalloderivatives of the enzyme are normally carried out in the presence of large molar excesses of these metal ions that can potentially affect both the enzyme and substrate. The fluorescence of all of the dansyl-peptides, as well as several other dansyl species, is quenched by Ni(II) and Cu(II), but not by Mg(II), Mn(II), or Zn(II). The absorption spectra of these dansyl substrates are also perturbed by Ni(II) and Cu(II). The rate at which maximal quenching for some dansyl species is attained after mixing with Ni(II) and Cu(II) is slow and the quenching is reversed on addition of EDTA. These results indicate that the quenching is the result of complex formation between the fluorophores and these metal ions. The association constants for the metal complexes have been determined from Stern-Volmer plots. In addition to complex formation, Ni(II) and Cu(II) cause the degradation of Leu-Gly-NHNH-Dns through a two step mechanism involving loss of dansic acid. Ni(II) and Cu(II) also partially quench the fluorescence of leucine aminopeptidase through contact with its surface accessible Trp residues. These observations indicate that care must be taken in stopped flow fluorescence studies of reactions between this enzyme and its dansyl substrates to avoid adverse effects brought about by Ni(II) and Cu(II).     

DNA mediated transformation of Aspergillus ficuum

Summary Two DNA-mediated transformation systems were successfully adapted to Aspergillus ficuum. Both the Escherichia coli hygromycin B resistance gene and the A. nidulans amdS gene transformation systems produced stable A. ficuum NRRL 3135 transformants. Cotransformation with the E. coli lacZ gene was also achieved with the hygromycin B system. In cotransformation a second unselected gene, in this case the lacZ gene which codes for -galactosidase, was also integrated and expressed in hygromycin B transformants. Since both of these transformation systems utilized dominant selection markers, they are potentially useful in other genetically uncharacterized filamentous fungi.