Efficiency of a cubic NaI(Tl) detector with rectangular cavity using standard radioactive point sources placed at non-axial position.

Low cost scintillation detectors as compared with HPGe detectors are considered to be one of most important radiation detection tools. Therefore, these detectors can be manufactured in different shapes and work at room temperature without any cooling systems, which added an extra advantage to it. This work presents a study of a cubic detector with a rectangular cavity in different experimental setup geometries, using standard point-like gamma-ray sources, where the efficiency of the detector in these geometries was the target to be studied. According to this aim, the data from the experimental measurements was used to determine the detector efficiency. An analytical calculation of the detector efficiency was done by using a new mathematical expression, this mathematical expression depends on the efficiency transfer technique and effective solid angle calculations. To support the mathematical model, the source-to-detector arrangement was simulated by Geant4 Monte Carlo code. All the compared efficiency results were found to be promising and trusted based on the calculated deviation percentages.

[NAT screening of viral infections in donors enhances blood safety].

The first experience in introducing the nucleic acid amplification technique (NAT) in an Indian blood service as compared with the established European practice is analyzed. Examination of 12,224 donor blood samples revealed 217 (1.78%) persons with markers of infections, including 8 (0.065%) persons only with markers of viral genome, without serological signs of infections. In India, enzyme immunoassay-negative NAT-positive donations were tens of times more detectable than in the developed countries, which is associated with the epidemiological features and the large (more than 50%) proportion of paid donors. By taking into account the fact that 4.6% of the preserved blood doses are annually rejected as defective in the Russian Federation, as evidenced by the screening of markers of infections, the introduction of NAT may be expected to reveal a large proportion of donors in the period of both a "seronegative window" and chronic carriers of hepatitis B virus with its blood content. Both intralaboratory monitoring using the certified standards and the laboratory work quality system as a whole are a necessary condition for introducing NAT into a blood service.

The role of adhesive interactions and extracellular matrix fibronectin from human polymorphonuclear leukocytes in the respiratory burst.

The Arg-Gly-Asp (RGD) tripeptide and ajoene were used for studying the role of adhesive receptors in the respiratory burst. Activation of the respiratory burst was examined by using luminol-dependent and lucigenin-dependent chemiluminescence. Recently, it was shown that ajoene, (E, Z)-4,5,9-trithiadodeca-1,6,11-trien-9-oxide, a substance isolated from garlic extract, inhibits the binding of fibrinogen to activated platelets by direct interaction with fibrinogen receptor (Apitz-Castro, R., Lederma, E., Escalante, J. and Jain, M.K. (1986) Biochem. Biophys. Res. Commun. 141, 145-150). Taking into consideration the structural and functional similarity of integrins, it would be reasonable to assume that ajoene as well as RGD can inhibit adhesive interactions of human neutrophils. We have shown that the effect of various activators on the respiratory burst was abolished by ajoene or RGD treatment. The inhibitory effect of RGD and ajoene was dose-dependent. The treatment of neutrophils with antiserum against human plasma fibronectin inhibited the respiratory burst in response to formyl-methionyl-leucylphenylalanine (fMLP) and phorbol 12-myristate 13-acetate (PMA). This effect is dose-dependent and reversible with the addition of fibronectin. These data indicate that the respiratory burst in human neutrophils is mediated by the integrin family of receptors and that interactions between the extracellular matrix fibronectin and cells are necessary for the respiratory burst.

[The ajoene blockade of integrin-dependent processes in an HIV-infected cell system]. / Blokada adzhoenom integrinzavisimykh protsessov v sisteme kletok, infitsirovannykh VICh.

Ajoene, (E,Z)-4,5,9-trithiadodeca-1,6,11-triene-9-oxide, isolated from extracts of garlic (Allium sativum) has been previously shown to inhibit platelet aggregation by inactivating allosterically the platelet integrin, GP IIb/IIIa. The structural and functional similarity of integrins led the authors to suggest that ajoene may also inhibit adhesive interactions and fusion of leukocytes. Synthetic stereoisomers of ajoene synthesized by the authors exhibited equal antiaggregatory activities (IC100 approximately 50 microM for platelets; IC100 approximately 10 microM for fMLP-stimulated neutrophils). Racemic ajoene inhibited the fusion of H9 cells with HIV-infected H9:RF cells (IC50 approximately 45 microM; 16 h of incubation) and also exhibited a degree of antiviral activity (IC50 approximately 5 microM as assessed by inhibition of HIV-1/CEM/Lav 1 Bru replication in CEM13 cells; m. o. i. 0.1; 72 h). A considerable increase in the latter became evident when the compound was administered in aliquots of 50 microM per 12 h of incubation (inhibition by 30%; total concentration 0.25 microM; 72 h).(ABSTRACT TRUNCATED AT 250 WORDS)

[Participation of cyclic nucleotides in immunogenesis and immune reactions of lymphocytes]. / Uchastie tsiklicheskikh nukleotidov v immunogeneze i immunnykh reaktsiiakh limfotsitov.

The paper deals with generalized literary and author's own data testifying to the role of cyclic nucleotides as mediators in the effect of specific and nonspecific factors on immunogenesis, from the proliferation of stem hemopoietic cell of bone marrow to the reaction of T and B lymphocytes to antigens. It is shown that changes in the system of lymphocytes cyclic nucleotides are most probably secondary in response to changes in intracellular concentration and distribution of calcium ions. Certain evidence is presented on immunopharmacological preparations based on cyclic nucleotides, their analogs and preparations modulating the activity of phosphodiesterases.

[Content of 5-methylcytosine in DNA fractions in normal human leukocytes and in chronic leukoses]. / Soderzhanie 5-metiltsitozina vo fraktsiiakh DNK leikotsitov cheloveka v norme i pri khronicheskikh leikozakh.

A procedure is described for fractionation of DNA obtained from leukocyte lysates of healthy donors and of patients with chronic leukoses using silica gel column chromatography. Lymphocytes and granulocytes of healthy donors as well as leukocytes from patients with chronic lympho- and myeloleukosis were dissimilar in the fractional composition of DNA. Nucleotide composition was studied; content of the DNA I fraction varied distinctly both in healthy donor granulocytes and in leukocytes of patients with chronic myeloleukosis as well as in leukocytes of patients with chronic lympho- and myeloleukosis. All the DNA fractions from leukocytes of healthy donors and of patients with chronic leukoses were dissimilar also in content of 5-methylcytosine.

[Comparison of the protein composition of the chromatins of several species of vertebrates]. / Sravnenie belkovogo sostava khromatinov nekotorykh vidov pozvonochnykh

Protein composition of chromatins from the liver of various Vertebrates (frog, turtle, hen and rat) has been compared by the immunological method of double diffusion in gel. It was shown that non-histone chromosomal proteins and histones exhibit evident species specificity.

[Immunoenzyme, turbidimetric and affinity chromatographic methods of determining the fibronectin level in human plasma (comparability of results and effect of conditions and duration of blood storage)]. / Immunofermentnoe, turbidimetricheskoe i affinno-khromatograficheskoe izmerenie kontsentratsii fibronektina v plazme krovi cheloveka (sopostavimost' rezul'tatov i vliianie uslovii i vremeni khraneniia krovi).

Immunoenzymatic, turbidimetric and affinity chromatography methods used for estimation of fibronectin concentration exhibited the similar results but the turbidimetric procedure was more simple and less time-consuming. Concentration of fibronectin was not decreased in blood maintained in polymer container "Gemacon 500" within 48 hrs both at 4 degrees and 20 degrees, while about 40 = 50% of fibronectin was lost after storage of blood in glass flasks under similar conditions.

[Study of the DNA structure of peripheral blood leukocytes, proliferating lymphoid and tumor cells according to the rate of alkaline denaturation of DNA lysates]. / Izuchenie struktury DNK leikotsitov perifericheskoi krovi, proliferiruiushchikh limfoidnykh i opukholevykh kletok po skorosti shchelochnoi denaturatsii DNK lizatov.

Direct fluorometry was used to identify quantitative differences in the DNA structure of human peripheral blood leukocytes and proliferating lymphoid cells. The differences should be taken into account in the study of varied damaging actions.

[Blood fibronectin and liver phagocytic function in peritonitis patients]. / Fibronektin krovi i fagotsitarnaia funktsiia pecheni u bol'nykh peritonitom.

The concentration of blood fibronectin and the state of the phagocytic function in the liver was studied in 19 patients with an emergency pathology of the abdominal cavity complicated by the infective-toxin shock and polyorganic insufficiency. Patients with severe abdominal pathology had a considerably decreased level of circulating fibronectin, disturbed phagocytic function of the liver and development of the hypercatabolic state. Hypofibronectinemia was accompanied by polyorganic disorders, systemic bacteriotoxemia and disseminated intravascular coagulation. Causes of hypofibronectinemia and its role in pathogenesis of systemic complications in patients with emergency abdominal pathology are discussed.