Leukocyte-derived inhibitory activity in patients with myelodysplastic syndrome

Leukocyte-derived inhibitory activity inhibiting the entry of normal progenitor cells of granulocytes and macrophages (CFU-GM) into the S-phase of a cell cycle was investigated in 16 patients with different forms of myelodysplastic syndrome (MDS). The presence of this inhibitory activity was analysed in medium conditioned with low-density cells obtained from peripheral blood of MDS patients. The inhibition rate was measured by 3H-thymidine suicide technique with subsequent cultivation of pretreated cells in semisolid agar medium. Low-density cells from MDS patients of various types were studied: from the twelve patients with refractory anaemia (RA or RAS) only three were positive, one patient with chronic myelomonocytic leukaemia (CMML) was negative while one patient with refractory anaemia with excess of blasts (RAEB) and two patients with RAEB in transformation (RAEB-T) were positive with respect of the described test. In two patients with RA, who underwent a long-term investigation, the production of leukocyte-derived inhibitory activity preceded the development of disease into RAEB or RAEB-T. In five positive cases, supernatants were incubated with antiserum against human placental ferritin; with one exception, the inhibitory activity was neutralized.     

Ethmoidal endocranium in primitive triassic amphibians

Three-dimensionally preserved and chemically prepared skulls and natural casts of representatives of the families Benthosuchidae, Melosauridae, and Capitosauridae yield data on the structure of the ethmoidal endocranium, i. e. of those nasal cranial structures that consisted originally of cartilage. This study demonstrates that the ethmoidal endocranium was principally a dorsoventrally compressed plate, pierced by a broad and oblique canal which communicated anteriorly with the outer dorsal surface by the fenestra endonarina and posteriorly with the mouth cavity by the fenestra endochoanalis(seu foris). The canal was very short, and housed the olfactory organ. The ethmoidal endocranium was connected with the palatoquadrate by the commissura quadratocranialis anterior; there was no lateral ethmoidal commissure, however, in older individuals the anterior section of the palatoquadrate might also contact the postchoanal part of the nasal endocranial skeleton.     

Effect of detergents on aspartate ammonia-lyase activity inEscherichia alcalescens

The effect of twelve detergents on aspartate ammonia-lyase activity of Escherichia alcalescens used for the production of L-aspartic acid was tested. Best permeabilization was found with Triton X-100, Slovafol 910 and Corona, a mixed commercial preparation. In contrast to Triton X-100 and Slovafol 910, a much narrower range of suitable concentrations was observed with Corona.     

Maintenance of aPaecilomyces variotii culture in the frozen and Freeze-dried state and in distilled water

The highest number of viable.elements ofPaecilomyces variotii, forming colonies after a 1-year maintenance, was detected in frozen sample. Decreased viability of the frozen culture and culture maintained in distilled water was usually statistically significant after 1 year and decreased further with increasing age of the culture used for sample preparation. Freeze-drying also significantly decreased the strain viability, depending on culture age. In the freeze-dried culture stored in a refrigerator the relative number of viable elements was substantially higher than after storage at room temperature. After a 3-year storage of freeze-dried P.variotii in a refrigerator 14-44% of culture elements survived, as compared with the number detected immediately after freeze-drying.     

Benzothiazolium salts—relationships between their structure,toxicity and effect on the plastid system ofEuglena gracilis

The effects of 41 benzothiazolium salts on Euglena gracilis were characterized with regard to the influence on growth and on chlorophyll synthesis, and to their ability to induce permanent loss of chloroplasts. Some salts induced white mutants of E. gracilis (the first benzothiazole derivatives with this activity). The relationship between the biological effect and chemical structure was confirmed and expressed quantitatively by means of Free - Wilson and Fujita - Ban analysis.     

The hair of the common hare (Lepus europaeus Pall.) and of the common vole (Microtus arvalis Pall.) as indicator of the environmental pollution

We made the INAA of hair of the common hare (Lepus europaeus Pall.) and of the common vole (Microtus arvalis Pall.) living in the emission zones. Both the hare and the vole are almost exclusively herbivores; they consume relatively large amounts of contaminated food and mirror reliably the contamination degree of the respective ecosystem. The use of free-living animals for the control of the environmental quality may complete effectively the information obtained by examination of habitants. Though the free-living animals lead a rather different way of existence it has been found that the analyses of their hair correlate very well with the analyses of human hair. It may be expected that the changes of concentrations of heavy metals will manifest themselves earlier in animals than in men, because the animals are strictly tied to the local food sources. The hair samples of hares contained increased concentrations of Sm, La, Au, As, Se, Cr, Sc, Fe, Ce, Th and Co. The hair of voles showed increased concentrations of Sm, La, Zn, As, Se, Cr, Sc, Fe, Sb, Ce, Cs and Co. A conspicuous trend towards the cumulation in hair was observed in the following elements: As, Se, Sc and Fe. The increase of their concentrations in the hair of animals from the emission regions amounted as such as to 10(3)%.     

Arbovirological survey in Silica plateau area, Roznava District, Czechoslovakia

The serosurveys conducted in the Silica plateau area of the Slovak karst region revealed the presence of specific neutralizing antibody against tick-borne encephalitis (TBE) virus in 18% of local inhabitants (33 examined, mostly goats and sheep farmers), 54% of goats (26 examined), 18% of sheep (120 examined) and 13% of cattle (60 examined), against Lipovník (LIP) virus in 30% of inhabitants, 88% of goats, 55% of sheep and 45% of cattle, and against Bhanja (BHA) virus in 27% of inhabitants, 46% of goats, 29% of sheep and 23% of cattle. The results of hemagglutination-inhibition tests with TBE and BHA antigens were analogous. A detailed analysis of these serologic data points to a recent enhancement of the circulation of LIP and BHA viruses and to a very low TBE virus activity in this natural focus of arboviral infections. The immunological surveys of the 32 former "Roznava disease" patients, conducted 25 years after an extensive epidemic of a TBE virus infection that originated in Roznava in 1951, revealed the presence of neutralizing (and also hemagglutination-inhibiting) antibodies against TBE virus in as many as 78% of cases. Antibodies against LIP and BHA viruses were also detectable in the sera of 16% and 9%, respectively, of these individuals. Populations of the ectoparasites examined for the presence of arbovirus comprised 231 Ixodes ricinus, 806 Dermacentor marginatus and 204 Haemaphysalis punctata ticks and 117 specimens of the louse-flies Melophagus ovinus. Two strains of arbivirus that were antigenically related to Lipovník and Tribec viruses belonging to a group of Kemerovo viruses were isolated from male and female I. ricinus ticks collected from cattle.     

Mitogen Stimulation of Lymphocytes in Pigs with Hereditary Vitamin C Deficiency

Recently an inherited vitamin G deficiency in the pigs presumably based on an autosomal recessive gene was decribed* Homozygotes are in contrast to heterozygotes and normal pigs unable to synthesize ascorbic acid. In an experiment comprising 3 littermate pigs, 2 homozygous and 1 heterozygous for the vitamin C deficiency gene, the influence of ascorbic acid depletion, and repletion on mitogen stimulation of peripheral blood lymphocytes was studied. Ascorbic acid depletion of the vitamin C dependent pigs resulted in a rapid decline in plasma ascorbic acid. Response of lymphocytes to stimular tion with Concanavalin A (Con A) and phytohemagglutinin M (PHA) decreased more slowly reaching a minimum, which coincidedi with the occurrence of the first clinical symptoms of scurvy. Following resupplementation with vitamin C the plasma content of ascorbic acid rapidly returned to normal, while the lymphocyte response to Con A and PHA stimulation only gradually approached the initial values. The repletion with ascorbic acid caused a transitory increase in the response to pokeweed mitogen (PWM) stimulation. The significance of these findings in relation to the cellular immune system in normal pigs is discussed.