<Emphasis Type="Italic">R</Emphasis>-Deprenyl: Pharmacological Spectrum of its Activity

Deprenyl has been discovered by Knoll and co-workers. The R-enantiomer of deprenyl (selegiline) is a selective and irreversible inhibitor of the B-isoform of monoamine oxidase (MAO-B) enzyme. Due to its dopamine potentiating and possible neuroprotective properties it has an established role in the treatment of parkinsonian patients. By inhibiting MAO-B enzyme, R-deprenyl decreases the formation of hydrogen peroxide, alleviating the oxidative stress also reduced by increased expression of antioxidant enzymes (superoxide dismutases and catalase) reported during chronic treatment. It was shown to prevent the detrimental effects of neurotoxins like MPTP and DSP-4. R-Deprenyl elicits neuroprotective and neuronal rescue activities in concentrations too low to inhibit MAO-B. It is extensively metabolized and some of the metabolites possess pharmacological activities, thus their contribution to neuroprotective properties was also suggested. The recently identified deprenyl-N-oxide is extensively studied in our laboratory. Effects other than neuroprotection, like influencing cell adhesion and proliferation cannot be neglected.     

Elemental analysis of samples of biological origin relative to their protein content by means of charged particle bombardment

The particle-induced X-ray emission (PIXE) method and the 14N(d,p)15N nuclear reaction are combined for simultaneous trace element and nitrogen determination. Measurement of nitrogen content often allows the relating of the elemental concentrations determined by PIXE to the protein content of the sample. For the measurements only a small amount of sample material is needed; therefore, it is possible to keep track of the quantity of a certain element in the successive steps of a biomedical separation process. In about 10 min, trace element concentrations in the ppm range can be determined with a statistical accuracy of about 10%.     

Phylogenetic relationships among Fusarium species measured by DNA reassociation

Deoxyribonucleic acid of 11 Fusarium species (F. acuminatum, F. arthrosporioides, F. avenaceum, F. culmorum, F. graminearum, F. heterosporum, F. moniliforme, F. oxysporum, F. sambucinum, F. semitectum, F. solani) have been compared with respect to their physical characteristics (T_m, % G + C), homology values and nucleotide sequence divergence.A phylogenetic tree based on physical characteristics, homology values and differences in percentage divergence of Fusarium species DNAs has been constructed.     

Effects of exogenous nitric oxide on photosynthesis

Nitric oxide (NO) is an important signalling molecule with diverse physiological functions in plants. In plant cell, it is synthesised in several metabolic ways either enzymatically or nonenzymatically. Due to its high reactivity, it could be also cytotoxic in dependence on concentration. Such effects could be also mediated by NO-derived compounds. However, the role of NO in photosynthetic apparatus arrangement and in photosynthetic performance is poorly understood as indicated by a number of studies in this field with often conflicting results. This review brings a short survey of the role of exogenous NO in photosynthesis under physiological and stressful conditions, particularly of its effect on parameters of chlorophyll fluorescence.     

Use of elution marker for the intratypic characterization of poliovirus strains.

Elution marker was used for intratypic characterization of poliovirus strains with Al(OH)3 gel as adsorbent. The virion suspensions to be tested were partially purified by chromatography and labelled with 32P. In the labelled preparations of wild virus strains practically all radioactivity was found in virus-specific bond, whereas in those of the vaccine strains and isolates of vaccine origin a considerable, but variable, proportion of the activity was bound to residual cell components. For this reason, the EC50 value (i.e. the phosphate molarity corresponding to the 50% adsorption equilibrium of virions), for the vaccine and vaccine-like strains showed a wide scattering. The activity bound to cell components was removable from the gel with 0.005 M phosphate buffer, whereas the elution maxima for all the poliovirus strains examined so far were over 0.02 M. The elution marker was calculated for 25 type-2 and 30 type-3 strains, all isolated during or soon after vaccination periods from cases suspect of poliomyelitis, both with and without taking into account the cell-bound activity. In the latter case, the EC50 values agreed with that for the corresponding reference vaccine strain much better than in the former; furthermore, the type-2 reference vaccine strain and the type-2 isolates, indistinguishable from the wild reference strain by the original method, could easily be differentiated on the basis of the corrected EC50 value. The possibility that the lack of an appreciable proportion of cell-bound radioactivity may reflect the pathogenicity of poliovirus strains is discussed.     

Calcium ion uptake,somatotropin release,and fine structure of somatotrophs in cultures of the rat anterior pituitary upon the action of an oligopeptide (Boc-Gln-Leu-Lysinal)

Summary Cultured cells from the anterior pituitary glands of adult rats were treated with the tripeptide aldehyde proteinase inhibitor, Boc-Gln-Leu-Lys-H. The oligopeptide had a profound relesing effect on growth hormone, whereas the prolactin release remained unchanged at 10^–3 mol/l drug concentration after an incubation for 2 h. In the presence of the oligopeptide a time- and dose-dependent calcium influx into cultured cells has been shown which was proved to be almost completely antagonized with magnesium ions but not with Nifedipine. In addition, radioactive calcium ions could be detected in a number of cells by light microscopic autoradiography when cultures were treated with Boc-Gln-Leu-Lys-H for short periods. The selective Gel action of the oligopeptide on growth hormone producing cells has been demonstrated also in fine structural investigations: multigranular and single exocytotic profiles have been observed. Accordingly, we have postulated that Boc-Gln-Leu-Lysinal mimics the effects of the known ionophores. Its mode of action needs, however, further studies especially on isolated somatotrophs.     

Complete Genes May Pass from Food to Human Blood

Our bloodstream is considered to be an environment well separated from the outside world and the digestive tract. According to the standard paradigm large macromolecules consumed with food cannot pass directly to the circulatory system. During digestion proteins and DNA are thought to be degraded into small constituents, amino acids and nucleic acids, respectively, and then absorbed by a complex active process and distributed to various parts of the body through the circulation system. Here, based on the analysis of over 1000 human samples from four independent studies, we report evidence that meal-derived DNA fragments which are large enough to carry complete genes can avoid degradation and through an unknown mechanism enter the human circulation system. In one of the blood samples the relative concentration of plant DNA is higher than the human DNA. The plant DNA concentration shows a surprisingly precise log-normal distribution in the plasma samples while non-plasma (cord blood) control sample was found to be free of plant DNA.     

Studies on the sense of smell to ketone compounds in a Hungarian population

Summary The authors examined the sense of smell of 187 students (105 boys and 82 girls), aged from 15 to 19 years, of a technical school. Tests for the ability to smell are reported only in very few papers in the literature; so it was necessary to elaborate an own test procedure. In order to collect olfactory thresholds, a sorting technique based on the use of a serial dilution of the substances, was used similarly to the method for testing taste sensitivity to P.T.C. It was observed as a new phenomenon that the human population showed a polymorphism concerning ketone compounds, i.e. acetone and methylethylketone (MEK); the distribution of thresholds gave a bimodal curve for acetone and a trimodal one for MEK. Correlation — though not very strong — between the thresholds for these compounds was found. Retesting 1–3 months later with acetone showed a fairly good fit. Finally the possibility of the role of genetic factors in the ability to smell ketone compounds is suggested.