Lectin histochemistry for detecting cadmium-induced changes in the glycosylation pattern of rat placenta

Cadmium (Cd) is an industrial and environmental pollutant that produces toxic effects on gametogenesis, pre- and post-implantation embryos, and the placenta. Because the effects of acute Cd intoxication on the placenta are not well understood, we investigated changes in its glycosylated components in Cd treated dams at days 4, 7, 10 and 15 of gestation using lectin histochemistry. CdCl₂ was administered to pregnant rats; control animals received sterile normal saline. Placentas were processed for DBA, Con A, SBA, PNA, UEA-I, RCA-I and WGA lectin histochemistry to evaluate changes in the carbohydrate pattern of the placenta that might modify cell interactions and contribute to embryonic alterations. Lectin binding was analyzed in the yolk sac; trophoblast giant cells; trophoblast I, II and III; spongiotrophoblast cells and endovascular trophoblast cells in the chorioallantoic placenta. Our lectin binding patterns showed that Cd caused alteration of SBA and DBA labeling of trophoblast-derived cells, which suggested increased expressions of α and β GalNAc. Cd also caused decreased UEA-1 binding affinity, which indicated fewer α-L-Fuc residues in placentas of Cd treated dams. The nonreactivity in trophoblast I of the control placentas incubated with Con-A contrasted with the labeling in placentas of experimental dams, which indicated increased expression of terminal α-D-Man, and α-D-Glc residues. We found that Cd altered the reactivity of placenta to several lectins, which indicated modification of the glycotype presented by the fetal component of the placenta. We report that Cd exerts a deleterious effect on the glycosylation pattern of the placenta.     

Changes in the intensity of protein synthesis in the gastric mucosa following the laser irradiation of a duodenal ulcer]

The intensity of protein synthesis (incorporation/pool) is usually low in normal stomach mucosa and enhanced in exacerbation of peptic ulcer; following the effective laser therapy it decreases only in one third of cases. Therefore the scarring of ulcer not always coincides with the normalization of protein synthesis. The results characterize also the community of reactions in stomach and duodenal mucose membranes. The changes in protein synthesis intensity following the laser irradiation depended neither on the initial size of ulcer nor on the age of patient and the total duration of disease.     

Ribonuclease activity in preparations of human leukocyte interferon]

Preparations of human leukocyte interferon obtained by multi-stage purification procedure exhibited ribonuclease activity with the optimum at pH 7.0--7.5. The enzyme possessed the endonuclease action mechanism. Most substances studied for their effect on the RNA-ase activity in human interferon preparations showed many of them to act on the enzyme in the same way as on other ribonucleases. However, dithioerythritie, a reducing agent for disulfide bounds, activated the ribonuclease in the interferon preparation, as distinct from the pancreatic ribonuclease, which was inhibited by this preparation. Patterns of protein and RNA-ase distribution were obtained by electrophoresis in polyacrylamide gel.     

The effect of physicochemical factors on the activity of DNA-dependent DNA polymerases in Acholeplasma laidlawii PG-8]

The biological and physico-chemical properties of DNA-dependent DNA-polymerases of Acholeplasma laidlawii PG-8 have been studied. The optimal parameters of maximal enzymatic activity are determined. It is stated that N-ethylmaleimide in concentration of 1 mM activated DNA-polymerase I by 52%, whereas DNA-polymerase II with reagent concentration of 0.5 mM demonstrated the peak of activity exceeding the control only by 10%. Spermidine in concentration of 1.5 mM for the first form of DNA-polymerase and 0.15 mM-for the second one increased the ability of both forms of polymerases to synthesize DNA by 10%. Aphidicolin added to the reaction medium up to concentration of 10 mg/ml decreased activity of forms I and II of enzymes by 83 and 68%, respectively. The presence of 0.6 mM of EDTA in the medium also negatively affected the activity of polymerases inhibiting it by 83% in form I and by 77%-in form II.     

Combined action of nucleosides and alpha-interferon in inhibiting the reproduction of the herpes simplex type-II virus

Therapeutic effect of four combinations of antiherpetic chemical preparations--acyclovir (ACV), 9-beta-D-arabinofuranosyladenine (ARA-A) and E-5-(2-bromovinyl)-2'-desoxyuridine (BVDU)--has been studied. Mutual enhancement was observed in all the combinations studied, except for ACV and ARA-A combination, where partial antagonism was observed. ACV + BVDU was shown to be the most optimal combination, with the minimum inhibitory concentration (MIC) of BVDU decreasing 400-fold. A significant enhancement of nucleosides antiviral effect was noted when the human leucocyte interferon was used with the combinations. Along with synergistic effect during the interaction of alpha-interferon with ACV the antagonism in the combination of alpha-interferon with ARA-A was observed.     

Interferons produced by the cells of newborn mice in the presence of sera from newborn and adult animals

Fibroblasts of newborn mice produced far less amount of interferon in the presence of sera from newborn animals than in the presence of sera from adult animals. The interferons obtained were purified by adsorption chromatography on porous glass and were analyzed by electrophoresis in polyacrylamide gel. It has been shown that antiviral activity of interferon preparations obtained in the presence of sera from newborn mice was associated with the fraction of 45 Kd. Addition into the growth medium of sera from adult animals led to the production by the same cells of interferon activity associated with 41 and 28 Kd fractions. It is assumed that the sera of newborn mice contained the components influencing the molecular content of interferon produced by the cells of newborn animals.     

The efficacy of exogenous and endogenous interferonization in preventing influenza]

In this work the results of using interferon (IFN), Dibasol and the combination of these preparations for the urgent prophylaxis of influenza and acute respiratory diseases (ARD) among the employees of the Gamaleia Research Institute of Epidemiology and Microbiology (USSR Acad. Med. Sci.) are summarized. Reaferon and Dibasol decrease ARD morbidity 2 times and leukocytic IFN decreases it 1.4 times, while the combined administration of Dibasol and IFN has proved to be ineffective. Reaferon is mainly a prophylactic remedy; it has been found to bring about almost no decrease in the number of patients at the peak of morbidity, while pronouncedly decreasing it in two weeks after the administration of the preparation. Dibasol has a curative effect, sharply interrupting the beginning rise of morbidity. Reaferon normalizes the characteristics of the IFN status, decreasing the amount of circulating IFN and enhancing the capacity of leukocytes for producing alpha-IFN and gamma-IFN. For the prophylaxis of respiratory infections the use of Reaferon is advisable 3-4 weeks prior to the beginning of the epidemic and then, when the first cases of infection are registered, the course of prophylaxis with Dibasol should be carried out.