Dietary polyamines promote the growth of azoxymethane-induced aberrant crypt foci in rat colon

We have examined whether dietary polyamines influence the formation and initial growth of azoxymethane (AOM)-induced aberrant crypt foci (ACF) in rat colon. Effects of a combination of dietary polyamines at three dose levels (putrescine: 50, 280, 740 nmol/g; spermidine: 10, 261, 763 nmol/g; spermine: 1, 31, 91 nmol/g) in the polyamine-poor AIN-76A diet were studied in animals in two different experimental situations: animals treated with AOM alone and animals treated with AOM + difluoromethylornithine (DFMO), a specific inhibitor of endogenous polyamine synthesis. In both experimental situations, dietary polyamines enhanced the growth of ACF, expressed as the number of large ACF (foci with three or more aberrant crypts, ACF > or = 3), whereas the formation of ACF, expressed as the number of ACF, was apparently not altered. In animals treated with AOM alone, maximal growth enhancing effect on ACF was nearly obtained with the median level of dietary polyamine. In rats fed a low polyamine diet, basic AIN-76A, DFMO reduced the growth of AOM-induced ACF by 83%. This inhibitory effect of DFMO was counteracted by dietary polyamines in a dose- dependent manner, and it was abolished at the highest level of polyamines. In conclusion, it was demonstrated that dietary polyamines are able to enhance the growth of AOM-induced ACF. Further, dietary polyamines reversed the DFMO-caused inhibition of ACF growth, probably by compensating for the DFMO-reduced endogenous polyamine synthesis.      

Percutaneous laser denervation of the zygapophyseal joints in the pain facet syndrome

Percutaneous laser denervation of archoappendicular joints in spinal pain was made in 15 patients from a study group. Percutaneous high-frequency denervation of archoappendicular joints was performed in a control group consisting of 15 patients with facet syndrome. A preoperative protocol for each patient included at least two diagnostic segmental blocks. A surgical intervention was morphologically substantiated during an experiment; the most optimum surgery protocol was chosen. Destruction was performed by 0.97-micron laser radiation for 4-6 sec at 5-10 W. The number of cases of a complete or partial pain regression, the duration of its impact, side effects and complications were determined. Of the 15 patients from the study group, 8 and 6 patients were observed to have a complete and significant pain regression (more than 50% of the baseline). No effect was achieved in one patient. The similar results were obtained in the control group. There were no postoperative infectious complications in the patients of both groups; transient pain dysesthesia was registered in one case. The findings have led to the conclusion that laser denervation of archoappendicular joints is effective in the pain facet syndrome.     

Effect of dexamethasone on activity of alkaline proteases and thymocytic pH

The effect of dexamethasone on activity of alkaline proteases and intracellular pH of rat thymocytes is studied. Dexamethasone increases the activity of alkaline proteases in the thymus. Intracellular pH changes under the effect of the hormone in two phases bothin vivo andin vitro. Possible mechanism of rapid acidification of the cytoplasm followed by its alkalization is discussed. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 3, pp. 310–312, March, 1998     

Hemodynamic characteristics and priority of blood refluxes in genesis of trophic ulcers in patients with varicose disease of lower extremities

An analysis of results of complex examination of 75 patients with varicose disease and trophic ulcers has shown that in 81.4% of the patients the main hemodynamic factor resulting in the development of ulcers was highly intensive total-subtotal reflux of blood along the superficial veins, and in 9.3% it was the highly intensive profound reflux along the posterior tibial veins. In 9.3% of the patients the priority of blood reflux was not established. Trophic ulcers were developing under the influence of low intensity refluxes of blood in the superficial, profound veins and perforators in elderly patients against the background of heart failure.     

Evasin‐3‐like anti‐chemokine activity in salivary gland extracts of ixodid ticks during blood‐feeding: a new target for tick control

Ticks exploit many evasion mechanisms to circumvent the immune control of their hosts including subversion of the communication language between cells of the immune system provided by chemokines and other cytokines. One subversive molecule secreted in the saliva of Rhipicephalus sanguineus is Evasin‐3, a structurally unique 7 kDa protein that selectively binds the neutrophil chemoattractants, CXCL8 and (with lower affinity) CXCL1. We compared anti‐human CXCL8 and anti‐mouse CXCL1/KC activities in salivary gland extracts prepared from adult Amblyomma variegatum, Rhipicephalus appendiculatus and Dermacentor reticulatus ticks during blood‐feeding. Both anti‐CXCL8 activity and anti‐CXCL1 activity were detected in all species and in both adult females and males, with consistently higher activity levels against CXCL8. These results suggest that Evasin‐3‐like activity is common amongst metastriate ixodid tick species, and provide further evidence of the importance to ticks in controlling neutrophils during blood‐feeding. As such, Evasin‐3 offers a new target for anti‐tick vaccine development.     

Oxidative Stress in HEp-2 Human Laryngeal Carcinoma Cells Induced by Combination of Vitamins B12b and C

Incubation of human laryngeal epidermoid carcinoma HEp-2 cells with hydroxocobalamin (vitamin B12b) and ascorbic acid (vitamin C) for 1 h initiated oxidative stress accompanied by damage to mitochondria and increase in intracellular oxidative activity. Studies of the kinetics of these processes showed that the increase in intracellular H2O2 activity and mitochondrial damage are more likely a result, but not the cause of cell apoptosis during the first hour of their incubation with vitamins B12b and C.     

Functional activity of hepatocytes in tissue fragments in a new bioreactor biological artificial liver

Functional activity of hepatocytes in a new bioreactor designed for culturing of liver tissue fragments under perfusion conditions was tested. Specific hepatic functions such as ammonium detoxification, urea and protein synthesis, and P-450-dependent metabolism of p-nitroanisole were maintained for 1–1.5 days. The bioreactor can be used as a bioartificial liver support apparatus. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 6, pp. 698–700, June, 2000