The effect of X-radiation on the process of lung clearance after inhalation of bacteria labelled with 3H-thymidine

The respiratory tract is cleared very effectively from the inhaled particles by the ciliated bronchial epithelium, secretion of secretory cells, and specialized phagocytic cells. Within 4 hours about 80% of the inhaled microorganisms are destroyed in the respiratory tract. The rate of removal of the micro-organisms from the lungs and their destruction may play a very important role in preventing infection development. The aim of the present experiment was to study the adverse effect of ionizing radiation on the mechanisms involved in cleaning the lungs. Wistar rats were used for this purpose. They received a dose of 500 cGy. The irradiated animals and the control non-irradiated ones inhaled in a PIANO IV apparatus Staphylococcus epidermidis labelled with tritiated thymidine. Determining the clearance of the bacteria from the bronchial tree and pulmonary tissue an impairment of the mechanisms clearing the lungs in the irradiated group was demonstrated. The effect of radiation may be related to a damage to the alveolar macrophages which are principally responsible for destroying bacteria at the level of pulmonary alveoli. The relatively radiation-resistant ciliated epithelial bronchial cells may have their efficiency reduced owing to disturbances in mucus secretion by the secretory cells.     

Ribonucleotide reductase--a "target" of the action of nitrosomethylurea]

The antitumor and toxic effects of methylnitrosourea (MNU) are determined through its metabolic pathways. In organism MNU is subject to hydrolytic decomposition and denitrosation. It has been shown in vivo studies that MNU abdominal injections of therapeutic doses caused the inhibition of ribonucleotide reductase in mouse spleen, and therefore the DNA synthesis depress. The effect may apparently contribute to antitumor property of MNU. It has been estimated that destruction of M2 subunit of the enzyme is occurred. The relation between the loss of ribonucleotide reductase activity and the inhibition of protein synthesis was discussed. Besides, the cancerogenic and mutagenic properties of MNU were discussed as a result of imbalance of DNA precursor pools. Changes in contents of Fe(3+)-transferrin, ceruloplasmin, methemoglobin in blood and spleen of animals after MNU injections have been found. The changes were reversible after single MNU injection and became irreversible after multiple injections.     

Adenosine Receptors in Myelin Fractions and Subtractions: The Effect of the Agonist (R)-Phenylisopropyladenosine on Myelin Membrane Microviscosity

In this article the existence of A1 adenosine receptors and the absence of A2 adenosine receptors in myelin membranes purified from pig brain white matter are demonstrated. The characterization of (R)-[3H]phenylisopropyladenosine ([3H]R-PIA) binding to purified myelin fractions was performed. The distribution of high- and low-affinity species of the A1 adenosine receptor was different in heavy, medium, and light myelin. The fluidity of myelin subfractions and of pig brain cortical membranes was estimated; the microviscosity of heavy myelin (5.4 poises) and of cortical membranes (5.1 poises) was similar and less than that of medium (7.8 poises) and light (8.2 poises) myelin. It was also demonstrated that the agonist R-PIA modifies the microviscosity of myelin membranes and that the degree of modification depends on the fluidity of the membrane assayed. These results suggest that adenosine receptors may have an important role in the functionality of myelin membranes.     

土壤重金属污染的酶学诊断:紫色土Cd、Cu、Pb和As对水稻根系脱氢酶的影响

本文通过酸性紫色土和石灰性紫色土中不同浓度Cd、Cu、Pb、As对水稻根系脱氢酶的影响研究,揭示了脱氢酶受抑制与产生抗性的过程。在低浓度时,土壤Cd、Cu、Pb、As对脱氢酶的影响较敏感,能因元素的不同性质反映土壤类型影响的差别。最后,以脱氢酶受抑制与初始抗性峰出现的转折点相应的土壤浓度为依据,确定了两种紫色土Cd、Cu、Pb、As的临界浓度。     

Radiologic endovascular prosthesis of the renal arteries in patients with renovascular hypertension]

A high percentage of restenoses after roentgenovascular dilatation of the renal arteries laid the basis of a search for new therapeutic methods for these patients. Experiments on implantation of nitinol spiral endoprostheses showed their ability for long-term permeability of renal arteries, not causing their thrombosis and intimal spreading, destruction of formed elements of the blood, change in plasma proteins. Morphological investigations have shown rapid formation (during 14 days) of connective tissue neointima, covered on the side of the blood flow with the true vascular endothelium (ensuring a nonadhesive surface and laminar blood flow), around the coils of an endoprosthesis. This method after its experimental development started to be used in clinical practice. The authors reported the first experience in the clinical use of this method (12 patients with vasorenal hypertension). A 15-month follow-up revealed a stable antihypertensive effect in all patients.     

Accessibility for water molecules and relative stability of the A- and B-forms of DNA

Accessible surface areas of DNA molecules (A- and B-forms) for different probe particle radii were calculated for poly(dA).poly(dT) and poly[d(A-T)].poly[d(A-T)] sequences. The problem of different forms stability is discussed in connection with accessible surface area characteristics as well as coulombic interaction between base pairs. The coulombic interaction was shown to play an important role in sequence dependent stability of the DNA molecule.     

Phlinosides D and E, phenylpropanoid glycosides, and iridoids from Phlomis linearis.

Two new phenylpropanoid glycosides, phlinosides D and E were isolated from the methanolic extract of the aerial parts of Phlomis linearis, along with the known iridoid glucosides, lamiide, ipolamiide and auroside (= 5-hydroxy-8-epiloganin). On the basis of chemical and spectral evidence the structures of phlinosides D and E were determined as 3,4-dihydroxy-beta-phenylethoxy-O-beta-D-xylopyranosyl-(1----2)-al pha-L-rhamnopyranosyl-(1----3)-4-O-feruloyl-beta-D-glucopyranoside and 3,4-dihydroxy-beta-phenylethoxy-O-alpha-L-rhamnopyranosyl-(1----2) -alpha-L- rhamnopyranosyl-(1----3)-4-O-feruloyl-beta-D-glucopyranoside, respectively.     

Salinity-calcium interactions on growth and ionic concentration of Citrus plants

Two-year-old Navel orange scions (Citrus sinensis (L.) Osbeck) budded to either Cleopatra mandarin (C. reticulata) and Troyer citrange (C. sinensis × P. trifoliata) rootstocks were used in this experiment. Cleopatra manda in rootstock was considered more tolerant to salinity than Troyer citrange, and this property was attributed to a greater capacity to exclude chloride ions.Plants were grown under glasshouse conditions and supplied with nutrient solution containing either no or 45 mM NaCl. Calcium concentration was increased from 3 to 30 mM. Sodium, potassium, calcium and chloride concentrations in plant organs were analyzed after 90 days of treatment.Supplemental Ca was found to mitigate the adverse effects of salinity on plant growth, defoliation or leaf injury.Chemical analysis indicated that in plants grafted on Troyer citrange Ca restricted uptake and subsequent translocation of Na to the leaves and increased K concentration in both roots and leaves. However, in Cleopatra mandarin-grafted plants increasing Ca levels seemed to reduce transport of Na from roots to leaves, and Na accumulation in roots was associated with reduced concentration of K in this rootstock.Organ chloride analysis showed that Cl accumulation in leaves of plants grafted on both rootstocks was reduced when external Ca concentration increased, whereas Cl concentration in roots remained constant or increased. The data of distribution of Cl in plants showed that a high external Ca level increased Cl accumulation in the basal stem and roots, and reduced the transport of Cl from roots to leaves.     

《植物生态学的数量分类方法》一书简介

阳含熙、卢泽愚著的《植物生态学的数量分类方法》一书,已由科学出版社出版。植物生态学数量分类的研究是从五十年代开始的,由于计算工作量大,及至六十年代电子计算机普遍应用之后,才迅速地发展起来。许多具有不同观点的传统学派,如法瑞学派、英美学派、苏联学派等,都进行了数景分类的研究,并用它去验证原来传统分类的结果。目前,在国外植物生态学研究中已广泛采用数量分类的方法,每年都发表大量的文章及专著,并不断涌现出新的方法。作者参考了大量国外文献,并根据他们自己对我国森林、草原资料应用的经验,编写了本书,