Reperfusion injury after critical intestinal ischemia and its correction with perfluorochemical emulsion ＂perftoran＂

AIM: To investigate the anti-ischemic properties of perfluorochemical emulsion "perftoran" in mesenteric region. METHODS: Experiments were conducted on 146 nonlinear white male rats weighing 200-350 g. Partial critical intestinal ischemia was induced by thorough atraumatic strangulation of 5-6 cm jejunal loop with its mesentery for 90 min. Global critical intestinal ischemia was made by atraumatic occlusion of the cranial mesenteric artery (CMA) for 90 min also. Perftoran (PF, 0.8-1.0 mL per 100 g) in experimental groups or 0.9% sodium chloride in control groups was injected at 75 min of ischemic period. Mean systemic arterial blood pressure (BPM) registration, intravital microscopy and morphological examination of ischemic intestine and its mesentery were performed in both groups. RESULTS: During 90 min of reperfusion, BPM progressively decreased to 27.3±7.4% after PF administration vs 38.6±8.0% in the control group of rats with partial intestinal ischemia (NS) and to 50.3±6.9% vs 53.1±5.8% in rats after global ischemia (NS). During the reperfusion period, full restoration of microcirculation was never registered; parts with restored blood flow had leukocyte and erythrocyte stasis and intra-vascular clotting, a typical "non-reflow" phenomenon. The reduction of mesenteric 50-400 μm feeding artery diameter was significantly less in the PF group than in the control group (24±5.5% vs 45.2±3.6%, P<0.05) 5 min after partial intestinal ischemia. This decrease progressed but differences between groups minimized at the 90th min of reperfusion (41.5±4.2% and 50.3±2.8%, respectively). In reperfusion of rat's intestine, a significant mucosal alteration was registered. Villous height decreased 2.5-3 times and the quantity of crypts decreased more than twice. In the group of rats administered PF, intestinal mucosal layer was protected from irreversible post-ischemic derangement during reperfusion. Saved cryptal epithelial cells were the source of regeneration of the epithelium, which began to cover renewing intestinal villi after 24 h of blood flow restoration. View of morphological alterations was more heterogeneous in CMA groups. CONCLUSION: Systemic administration of perftoran promotes earlier and more complete structural regeneration during reperfusion in rats after partial and global critical intestinal ischemia.     

Extracorporeal methods of blood purification in cardiovascular diseases

Increasing sensitivity to drugs, elimination of endotoxicosis, recovery of normal homeostatic control after hemocarboperfusion help to break off the vicious circles associated with severe cardiovascular disorders, and improve the effect of subsequent medication. Hemocarboperfusion added to combined intensive care and resuscitation procedures was associated with a 82.9% success rate.     

Poly(ADP-ribosyl)ation enhancement in brain cell nuclei is associated with diabetic neuropathy

The study has been undertaken to evaluate the effect of streptozotocin (STZ)-induced diabetes on rat brain poly(ADP-ribose)polymerase (Parp) activity and assess whether and how a Parp inhibitor, nicotinamide (NAm), may potentially regulate the diabetes-induced changes. Experiments were carried out after 4 weeks of diabetes duration in rats treated with or without NAm (100 or 200 mg kg(-1) day(-1), injected intraperitonally for 2 weeks). Assays were performed in purified brain cell nuclei to determine Parp activity by incorporation of radiolabeled ADP-ribose moieties from nicotinamide adenine dinucleotide (NAD+) into nuclear proteins. NAD+ and ATP levels were measured by enzymatic procedures. DNA damage was detected spectrophotometrically. RESULTS: Parp activity but not NAD-glycohydrolase (NADase) was stimulated by 21% in diabetes vs. control while lowering effects of diabetes on NAD+ and ATP levels were observed. Increase in Parp activity was accompanied by accumulation of malondialdehyde (MDA) and increase in DNA breakage. Treatment with either 100 or 200 mg/kg NAm dose diminished both DNA damage and Parp activity and partially restored the NAD+ and ATP contents, which is probably associated with direct competitive inhibition of Parp as well as with NAm's ability to block diabetes induced oxidative stress. CONCLUSION: Poly(ADP-ribosyl)polymerase overactivation is involved in the development of brain dysfunction in diabetic neuropathy. The mechanism of brain disorders seems to be at least partially connected with a decrease in cellular content and altered subcellular distribution of Parp substrate, NAD+, which, in turn, results in a reduction of ATP level that leads to a total failure of oxidative metabolism. NAm in both doses is effective for the inhibition of poly(ADP-ribosyl)ation.     

Biomedical Aspects of Cardiac Massage in Experiments and Clinical Practice

Despite current successes in modern cardiology and heart surgery, the problem of restoring and maintaining cardiac function in cases of sudden arrest or ventricular insufficiency is still urgent. Different methods of mechanically assisting the heart and replacing its pumping function exist, and direct mechanical cardiac massage (DMCM) is one of the more important. Experimental results with dogs and calves on 2- to 4-h DMCM, cardiac massage lasting for up to 48 h, subsequent restoration of cardiac activity, and cardiac massage during experimentally induced myocardial infarction permitted clinical application in patients with myocardial infarction complicated by ventricular fibrillation. DMCM also permits extension of the possibilities of obtaining and transplanting donor organs. It is one of the variants for solving the problem of total and partial replacement of the pump function of the heart, and now makes it possible to solve some important problems in transplantation and cardiac resuscitation.     

Maintenance of the circulation and the restoration of heart function in the donor body by means of direct mechanical heart massage for subsequent transplantation (an experimental study)]

The possibility of maintenance of circulation and subsequent restoration of the function of the heart in the organism of the donor, after 10-minute arrest of circulation, for transplantation of the heart was investigated. Study of the hemodynamic, biochemical, metabolic, and structural changes in the myocardium after 2-hour mechanical massage without and with pharmacological protection of the myocardium (glucose--insulin--potassium, hydrocortisone, dipyridamole), without and with restoration of cardiac activity in the organism of the donor and the recipient after transplantation of the second heart by the method suggested by Moory et al. in artificially created left ventricular insufficiency showed that direct mechanical massage of the heart may be used for its short-term preservation in the donor organism.     

Esophageal obstruction due to enteral feed bezoar: A case report and literature review

This paper describes a rare complication of enteral feeding, esophageal obstruction due to feeding formula bezoar, and reviews the published cases. An attempt to re-insert the nasogastric tube in a chronically ventilated 80-year-old female fed via a nasogastric tube with Jevity^® failed. An esophagogastroduodenoscopy revealed an 18 cm-long concretion of the feeding formula, filling most of the esophageal lumen, which was removed endoscopically. Forty-two cases of feeding formula esophageal bezoars have been reported in the literature. The formation of feeding formula bezoars is triggered by acidic gastroesophageal reflux. The acidic pH in the esophagus causes clotting of the casein in the formula. Predisposing factors for bezoar formation are: mechanical ventilation, supine position, neurological diseases, diabetes mellitus, hypothyroidism, obesity and history of partial gastrectomy. Diagnosis and removal of the bezoar is done endoscopically. Feeding in a semi-recumbent position, administration of prokinetic agents and proton pump inhibitors may prevent this complication.     

Interpretation of the kinetocardiogram of the right heart

On the basis of ultrasonic Doppler valvulocardiography of 20 healthy men and catheterization of the right heart of 15 patients with acute large-focal myocardial infarction, the development of elements of the right kinetocardiograms (KCGr) is explored. Comparison of kinetocardiograms of the right heart with ultrasonic and catheterization data has demonstrated that KCGr can be used to examine right heart contractions of cosmonauts and pilots in flight and on the ground as well as of patients to diagnose pathologies of the right compartments of the heart.