Nonsteroidal antiandrogen inhibition of testosterone metabolism in the prostate

The effect of prolonged administration of antiandrogen flutamide (FT) on testosterone (T) metabolism in the prostate (P) of intact and castrated rats and animals receiving androgens with substitution purpose was studied. In intact animals the production of dehydrotestosterone from labeled T in vitro was decreased in 30 days by 50%. The influence of FT on 5 alpha-reductase was shown to be determined by the blockade of androgenic effects. Proceeding from the results of experiments with FT and its hydroxylated metabolite added to incubated homogenates of the prostate of intact animals it was assumed that FT hydroxylated metabolite mediated FT influence on T metabolism.     

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.      

The pathogenesis and correction of disorders of the heart rhythm in the early post-resuscitation period]

The frequency and nature of heart rhythm disturbances have been studied in experiments on random-bred male rats who survived 4- and 6-min clinical deaths of acute blood loss. Using correlation analysis it has been shown that the leading pathogenetic arrhythmogenic factors are: catecholamine excess, as well as excess of free fatty acids, lipid peroxidation products, lactate and Ca-ATPase inhibition. The efficacy of preventive (gutimin, inderal, oxipiridin-6, isoptin) and therapeutic (carnozin, creatinphosphate) use of the drugs affecting pathogenetic mechanisms of heart arrhythmias and thus stabilizing bioelectrical heart activity in the early postresuscitation period has been observed.     

Introduction of new technologies in teaching basic and clinical pathophysiology

The article contains data on teaching basic and clinical pathophysiology in Omsk state medical academy. Teaching process includes tests of the first and second level of difficulty, solving situational profession-oriented problems, quizzes, demonstration of patients and pathophysiological analysis of clinical syndromes, case reporting and recording.     

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.     

Cardioprotective effect of exogenous creatine phosphate in acute hemorrhage

Experiments on noninbred albino male rats under the conditions of the whole body and the isolated isovolumically contracting heart have shown that a substantial contribution to postresuscitative cardiac damages is made by energy deficiency that triggers a group of mechanisms of damaging cardiomyocytic membranes. Exogenous creatine phosphate (CP) reduces postresuscitative mortality rates, improves bioenergy, contractile and rhythmical functions of the heart, decreases the rate of myocardial lipid peroxidation, by showing as a whole a cardioprotective action. The latter is realized by directly protecting the cardiomyocytic sarcolemma and the improvement of energy metabolism is secondary. Despite the likely mediation of this effect, improved energy metabolism is undoubtedly a key point of the protective action of exogenous CP if the heart is postresuscitatively damaged.     

Functional metabolic heart impairment after acute lethal hemorrhage followed by resuscitation.

Effects of acute lethal blood loss on postresuscitation heart impairment has been studied. Experiments were performed in mongrel male rats anesthesized with sodium pentobarbital (25 mg/kg). Functional metabolic heart impairments have been evaluated in different terms after resuscitation by isolated perfused heart method (Fallen et al., J. Appl. Physiol, 22 (1967) 836-839). It has been established that maximal heart injury occurs in the first hours after resuscitation. It is supported by the following findings: depression of myocardium contractile function grew; enzyme excretion from cardiomyocytes in coronary flow increased: efficacy of glucose utilization by means of carried function decreased; pyruvate excretion in coronary flow elevated. Because of severe course of postresuscitation period functional metabolic heart disturbances are more pronounced and preserved for a long time.