The Stroop effect on Slovak-Hungarian bilinguists

We studied the processes of interference vs language automatisms in a group of Slovak-Hungarian bilinguists (N = 19, age 13 years) and compared their performance in the Stroop test with two control groups - Slovak (N = 24) and Hungarian (N = 31) monolinguists of the same age. - The Stroop effect, whose essence is an interfering effect of the meaning of the word on its physical characteristic - colour, proved to be a suitable method in the study of information processing in the semantic memory of bilinguists as well as in determining dominance of one language over the other. Slovak-Hungarian bilinguists showed, as a rule, shorter times in Hungarian and approximated in their performance Hungarian monolinguists. It can be assumed that reaction times in the Stroop test are conditioned not only by interference of the other language but also by language automatisms, whereby interference and speech automatisms are in an indirect correlation. - The results thus indicate that processes of interference and language automatisms cannot be separated. Dominance of one language structure over the other (Hungarian over Slovak) was confirmed not only in our experimental method but also in the subjective rating.     

Nodular fasciitis initially diagnosed by aspiration cytology

A case of nodular fasciitis diagnosed by fine needle aspiration cytology is described. The cytologic findings included fusiform cells, mitoses, macrophages, multinucleated giant cells and mesenchymal elements in a characteristic granular background substance. The cytopathologic diagnosis was subsequently confirmed by the histopathologic study of the tumor and by electron microscopy.     

Maximal exercise capacity in adolescent European and Amerindian high-altitude natives

Forty-seven highland natives were given maximal exercise tests on a treadmill ergometer at 3,600 m. The subjects were grouped into four subsamples on the basis of ethnicity (European vs. Aymara) and age (young vs. old adolescent). Two-way ANOVA indicated that VO2max adjusted for body size did not differ significantly between ethnic groups but was significantly larger in older than younger boys within each ethnic group (p less than .05). This finding does not support the hypothesis that Amerindian highland natives have adapted genetically to hypoxia but is consistent with the hypothesis that the relatively high VO2max's of highlanders are acquired by developmental adaptation. Several measures of ventilation and oxygen transport capacity differed significantly between ethnic groups, suggesting that growing European and Aymara boys may respond somewhat differently to the stress of high-altitude hypoxia. However, despite these differences, VO2max, an integrated measure of the overall functional capacity of the oxygen transport system, did not differ significantly between ethnic groups, suggesting that both groups are equally capable of meeting the body's oxygen requirements during maximal exercise at high altitude.     

Carbon isotopic fractionation in heterotrophic microbial metabolism.

Differences in the natural-abundance carbon stable isotopic compositions between products from aerobic cultures of Escherichia coli K-12 were measured. Respired CO2 was 3.4% depleted in 13C relative to the glucose used as the carbon source, whereas the acetate was 12.3% enriched in 13C. The acetate 13C enrichment was solely in the carboxyl group. Even though the total cellular carbon was only 0.6% depleted in 13C, intracellular components exhibited a significant isotopic heterogeneity. The protein and lipid fractions were -1.1 and -2.7%, respectively. Aspartic and glutamic acids were -1.6 and +2.7%, respectively, yet citrate was isotopically identical to the glucose. Probable sites of carbon isotopic fractionation include the enzyme, phosphotransacetylase, and the Krebs cycle.     

Yeast species utilizing uric acid,adenine,n-alkylamines or diamines as sole source of carbon and energy

Yeast strains utilizing uric acid, adenine, monoamines or diamines as sole source of carbon and energy were isolated from several soil samples by the enrichment culture method. The most common species wasTrichosporon cutaneum. Strains ofCandida catenulata, C. famata, C. parapsilosis, C. rugosa, Cryptococcus laurentii, Stephanoascus ciferrii andTr. adeninovorans were also isolated. All strains utilizing uric acid as sole carbon source utilized some primaryn-alkyl-l-amines hydroxyamines or diamines as well. The ascomycetous yeast strains showing these characteristics all belonged to species known to assimilate hydrocarbons. Type strains of hydrocarbon-positive yeast species which were not found in the enrichment cultures generally assimilated putrescine, some type strains also butylamine or pentylamine, but none assimilated uric acid. Methanol-positive species were not isolated. Type strains of methanol-positive and of hydrocarbon-negative species did not assimilate uric acid, butylamine or putrescine. Assimilation of putrescine as sole source of carbon and energy may be a valuable diagnostic criterion in yeast taxonomy.     

19q distal trisomy due to a de novo (19;22)(q13.2;p11) translocation

A 2 4/12-year-old girl whith a de novo 46,XX,-22 + der(22), t(19;22)(q13.2;p11) karyotype is described. From this and other eight similar cases previously published, a typical phenotype in distal 19q trisomy is concluded.     

Macrocyclic trichothecene toxins produced by Stachybotrys atra strains isolated in Middle Europe.

A total of 17 strains of Stachybotrys atra isolated in Hungary and Czechoslovakia were cultured on Sabouraud agar, and the toxins produced by them were chemically analyzed by gas-liquid chromatography, high-pressure liquid chromatography, and mass spectroscopy. Furthermore, brine shrimp (Artemia salina) bioassay was used for the determination of toxicity of the compounds examined. Macrocyclic trichothecenes (satratoxins H and G, roridin E, and verrucarin J as well as two other unidentified macrocyclic trichothecenes) were found in all of the cultures tested. The identities of satratoxins H and G, roridin E, and verrucarin J were qualitatively determined by high-pressure liquid chromatography and gas-liquid chromatography. The ratio of satratoxins H and G and roridin E was found to be similar in each of the strains tested, but the amount of verrucarin J found was different in each of them. One of the unidentified macrocyclic trichothecenes was equivalent to the compound isolated by Harrach et al. (Harrach et al., Appl. Environ. Microbiol. 41:1428-1433, 1981). The other one proved to be a newly isolated macrocyclic trichothecene toxin. Stachybotryotoxicosis, one of the oldest mycotoxicoses known, and a serious problem in Middle Europe (Gy. Danko, Magy. Allatorv. Lapja 31:226-232, 1976), is believed to be caused by macrocyclic trichothecene toxins produced by Stachybotrys atra (R. M. Eppley, in Rodricks et al., ed., Mycotoxins in Human and Animal Health, p. 285-293, 1977). Forty years ago, the death of animals in the Soviet Union was associated with this fungus (C. U. Ruhliada, in Proceedings of the All-Union Sci. and Tech. Conf., p. 47-51, 1980).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of glutathione depletion on gluconeogenesis in isolated hepatocytes

Glutathione-depleted hepatocytes, by incubation with diethylmaleate (DEM) or phorone (2,6-dimethyl-2,5-heptadiene-4-one), i.e., substrates of the GSH S-transferases (EC 2.5.1.18), showed rates of gluconeogenesis from various precursors significantly lower than controls; however the rate of glucose synthesis from fructose was similar to that of controls. Isolated hepatocytes from rats pretreated with those substrates 1 h before isolation to deplete hepatic glutathione (GSH) also showed a decrease of the rate of gluconeogenesis from lactate plus pyruvate. Incubation of hepatocytes with L-buthionine sulfoximine, a specific inhibitor of gamma-glutamyl-cysteine synthetase (EC 6.3.2.2), resulted in a decreased rate of gluconeogenesis from lactate plus pyruvate only when GSH values were lower than 1 mumol/g cells. Freeze-clamped livers from GSH-depleted rats showed a higher concentration of malate and glycerol 3-phosphate, indicating that GSH depletion probably affects phosphoenolpyruvate carboxykinase and glycerol-3-phosphate dehydrogenase activities. Several indicators of cell viability, such as lactate dehydrogenase leakage, malondialdehyde accumulation, ATP concentration, or urea synthesis from different precursors, were not affected by GSH depletion under the experimental conditions used here. Besides, the GSH/GSSG ratio remained unchanged in all cases.     

Possible mechanism of the allosteric activation of cAMP receptor protein

Secondary structure of cAMP receptor protein of E. coli was predicted and compared to its crystal structure in the complex with cAMP solved by McKay and Steitz. The two conformations coincide in the DNA binding domain but strikingly differ in the other domain which binds cAMP and causes protein dimerization. The comparison indicates that cAMP destabilizes a very long helix instead of which sheets are formed creating a hydrophobic pocket where cAMP binds. Consequently, the helix-sheets isomerization and a resulting change in the relative monomer disposition in the dimer appears to be the origin of cAMP-induced allosteric activation of the protein. Extremely long helices were also predicted in the regions of the regulatory subunit of cAMP-dependent protein kinase from bovine cardiac muscle where cAMP binds. It is thus likely that the proposed mechanism of the effect of cAMP on protein structure has wider implications.     

Myoglobin: cytochrome b5 interactions and the kinetic mechanism of metmyoglobin reductase

Metmyoglobin (metMb) reduction by metMb reductase from heart muscle requires cytochrome b5 as electron-transfer mediator. The existence of a metMb-ferrous cytochrome b5 complex is demonstrated by mutual perturbation of the proteins' respective electrophoretic titration curves between pH 4 and 7. The same technique shows a preferential binding of cytochrome b5 over metMb by the enzyme. The paramagnetic hyperfine shifts in the cytochrome b5 1H NMR spectrum are perturbed by metMb, indicating the formation of a specific bimolecular complex with a 1:1 stoichiometry and a binding constant estimated to be less than 10 microM. The resonances assigned to the cytochrome b5 heme 6-propionate methylene group exhibit the largest complexation shifts. Computer modeling implicates lysines 47, 50, and 98 of metMb as contact points with cytochrome b5 carboxylate residues 43, 44, 60, and heme 6-propionate. The mechanism of the enzymatic reduction establishes metMb reductase as an NADH-cytochrome b5 oxidoreductase. Cytochrome b5 is reduced at near diffusion-controlled rates by the enzyme with a turnover number of 1000 min-1 X Km for the cytochrome is 0.9 microM versus 100 microM reported for the erythrocyte enzyme. Ferrous cytochrome b5 then reduces metMb nonenzymatically with an apparent rate constant of 4.9 X 10(4) M-1 min-1 X Acetylation of metMb, which does not affect its oxygen affinity or chemical reduction, renders it a poor substrate for enzymatic reduction. This study suggests a function for the three exterior lysine residues conserved in all mammalian myoglobin sequences: they are contact points for complexation with cytochrome b5.