Conditioned reflex switching over in unrestrained dogs

Conditioned switching-over was studied in unrestrained animals by means of instrumental alimentary conditioned reflexes of pressing the pedal. A complex of auditory and spatial factors (start-ground) served as conditioned alimentary signal. Backward connections were stable and were manifested in the teturning of the animal to the start-ground after feeding. It has been confirmed that the observed working readiness is a conditioned reflex of a tonic type.     

The somatic transformation of hens using high-polymeric DNA

The transformation studies were performed on genetically pure hen breeds: the donor was Russian white (white colour is a dominant character), the recipient was New Hampshire (pale-yellow-brown). The high-polymeric DNA (2.10(9) dalton) was isolated from erythrocytes and testicles of donor cocks and introduced to a fresh-laid egg of the recipient by replacing the protein. Two sets of experiments on 570 eggs were made. The single injection with 150 micrograms of donor DNA to the recipient egg induced a stable change of feathering colour (particoloured) in 46% of the hatched chicks, which remained for 6 months of observation. Thus, the high-polymeric DNA possesses the property of somatic transformation, that evidences for a high intact character of these preparations.     

Structure of the microflora of suppurative wounds and its sensitivity to antibiotics]

Clinico-bacteriological examination of patients with purulent infections showed that Staphylococcus was the predominating microflora in the wounds. Simultaneously an increasing role of gram-negative conditionally pathogenic bacteria was shown. Multiple drug resistance was found in the organisms tested. The highest sensitivity levels were observed to gentamicin, kanamycin, tetracycline, levomycetin. It was shown by means of special typing methods that staphylococci of phage group III and Ps. Aeruginosa of serotype II predominated in the infected wounds. When the pathological material contained the antibiotic resistant cultures of Ps. aeruginosa, Proteus, Klebsiella and toxigenic strains of Staphylococcus, a tendency for prolongation of the suppurative process was observed.     

Composition of DNA-bound lipids in the regenerating rat liver

Using thin-layer chromatography, the qualitative and quantitative composition of specific DNA-bound neutral lipids (NL) and phospholipids (PL) of regenerating rat liver 22 hours (S-phase) and 28 hours (G2-phase) after hepatectomy was studied. These lipids are represented by light and tightly bound components. The intact liver DNA contains minor amounts of NL and PL (15.02 micrograms and 5.82 micrograms per mg of DNA, respectively). The composition of DNA-bound lipids in rat liver differs markedly from that of nuclear membrane and chromatin total lipids. The former are strongly deficient in free cholesterol (FC), but are rich in cholesterol esters (CE), very rich in cardiolipin (CL) and deficient in phosphatidylcholine. The basic parameters of DNA-bound lipids of rat liver (NL/PL, CE/FC and cholesterol/PL) are more than unity and depend on the cell cycle. It was shown that in the S-phase the content of DNA-bound NL and PL increases 1.5-fold, in the G2-phase the NL content shows a still greater increase--2.3-fold, while that of DNA-bound PL decreases to normal values. The basic changes of the DNA-bound lipids in regenerating rat liver are due to FC, CE and CL, which determine the tissue specificity of these lipids.