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Biomedical subjects

J Bures

Publications and source records attributed to J Bures.

334 records · Page 19Linked to original sources
PubMedDate not supplied

The different expression of proteins recognized by monoclonal anti-heat shock protein 70 (hsp70) antibody in human colonic diseases.

Analysis of the expression of hsp70 (70 kDa heat-shock proteins) in normal and pathological tissues might prove their potential diagnostic and prognostic values. In the present study, we combined high-resolution two-dimensional polyacrylamide gel electrophoresis with immunoblotting to study hsp70 expression in normal, preneoplastic and neoplastic colonic mucosa. By monoclonal anti-hsp70 antibody, recognizing both the constitutive and inducible forms of hsp70, we have detected six charge isoforms localized in the pH 5.1-5.3 range and in the molecular mass range of 68-69 kDa in normal colonic mucosa. Immunostaining of hsp70 in polypous and malignant tissues revealed qualitative as well as quantitative changes in the expression of more acidic isoforms of hsp70 in comparison with normal tissue. Furthermore, the different basic isoforms of hsp70 were detected in chronically inflamed colonic mucosa from patients suffering from ulcerative colitis (UC) or Crohn's disease (CD). Besides the standard hsp70 protein pattern, additional proteins with molecular masses of about 39, 40, 74 and 75 kDa were variably immunostained in normal and pathological specimens. These observations suggest that hsp70 expression may be closely linked to disease etiology and/or pathophysiology.

Adenoma↗
PubMedDate not supplied

Rodent navigation after dissociation of the allocentric and idiothetic representations of space.

Analysis of the neural mechanisms of place navigation requires isolation of the landmark dependent allocentric and self-motion related idiothetic orientation modes. To assess their importance, rats were trained on a rotating (360 degrees/min) arena to avoid foot shocks applied in either a room frame defined sector of the arena or an idiothetically defined region of the floor. Independence of the respective allocentric and idiothetic engrams was revealed by simultaneous avoidance of both locations. The possibility that idiothetic orientation was confounded by allocentric intramaze cues was examined in an apparatus consisting of an inner rotating disc surrounded by a stationary belt. As long as the rat was on the moving disc, position of the 60 degrees shock sector was stable on the disk but projected from it to different parts of the belt. When the rat moved to the belt the shock sector was now stable on the belt, but its projection to the disk travelled over its moving surface. The rat always found the shock sector in an idiothetically correct position but the mutual shifts of the disk and belt eliminated the utility of local cues like scent marks for the idiothetic solution of the task. Purely allocentric orientation was required in a place recognition task in which pressing a lever mounted on a rotating arena was rewarded only when the operandum moved through an allocentrically defined 60 degrees segment of its trajectory. Place recognition was manifest by increased bar pressing rates on approach to and inside the reward zone. These methods may reveal how hippocampal place cell activity correlates with both allocentric and idiothetic aspects of spatial orientation.

Animals↗
PubMedDate not supplied

Influence of rapid amino acid and lipid emulsion administration on gas exchange and resting energy expenditure.

The aim of this study was to observe the effect of rapid lipid and amino acid infusion on resting energy expenditure (REE) in patients on parenteral nutrition. Eight people were studied. After 8 h of saline administration, they received 20% lipid emulsion and 8% amino acid solution during the next 5 h (rate 3.8 mg.kg-1.min-1 fat and 1.9 mg.kg-1.min-1 amino acid). Before the onset of the infusion and 3 and 5 h after, gas exchange and REE were measured. The rapid lipid emulsion administration led to a significant rise in serum triglyceride level. A significant increase in VO2 (from 269.0 +/- 66.8 to 319 +/- 55.8 ml/min) and REE (from 1858 +/- 438 to 2155 +/- 385 kcal/24 h) was observed 5 h after the onset of substrate administration (P less than 0.01). Pulmonary ventilation and VCO2 production were not influenced by the infusion. The thermic effect of nutrients administered reached 3.5 and 6.5% 3 and 5 h after the start of infusion, respectively. We conclude that REE can be increased by the rapid administration of lipid-based parenteral nutrition.

Adult↗
PubMedDate not supplied

Ethological models in research into the neural mechanisms of short-term memory.

Rats are protected against intake of toxic diets by specific evolutionary prepared behavioral adaptations. Intake of potentially dangerous novel food is reduced by neophobia. The taste signal is stored for several hours in a short-term memory file from which it gradually emerges in form of a permanent gustatory engram labeled as safe, when there are no adverse effects of feeding, or as aversive, when visceral symptoms of poisoning appear in the critical post-ingestion interval. The experimental evidence reviewed indicates that positive labeling (manifested by attenuation of neophobia) requires intact higher brain functions whereas the aversive experience (manifested by conditioned taste aversion) is recorded even under deep coma. The biological significance of the different neural mechanisms underlying the above forms of gustatory-visceral associations is discussed.

Animals↗
PubMedDate not supplied

Functional ablation by spreading depression: possible use in human stereotactic neurosurgery.

Spreading depression (SD) of EEG activity was elicited by microinjection (5 microliter) of 5% potassium chloride into the caudate nucleus (n = 7) or hippocampus (n = 3) during stereotactic brain surgery in patients with focal epilepsy. An electrode-cannula assembly for eliciting and recording the slow potential waves of SD is described. The parameters of SD in human brain are similar to those in lower mammals. Functional ablation by SD can be used as a diagnostic tool in neurosurgery.

Caudate Nucleus↗
PubMedDate not supplied

[Shifts in the constant potential in the structures of the rat brain in focal ischemia and systemic hypoxia].

The role of spreading depression (SD) in the development of ischemic brain damage in rats was studied in two models: focal cortical ischemia provoked by a photothrombotic occlusion of the middle cerebral artery (MCA) and systemic hypoxia induced by breathing with 0.8% carbon monoxide (CO). Spontaneous cortical SD waves occurring during illumination were found to delay the irreversible MCA occlusion. Thrombosis was probably prevented by episodes of striking vasodilation and hyperemia lasting for 1-2 min and accompanying every SD wave. The SD-induced hyperemia after permanent MCA occlusion seems to improve the oxygen supply of the penumbra zone. During hypoxia induced by one-hour respiration with 0.8% CO, COHb saturation of the blood reached 50-60%. SD waves occurred in different brain regions of lightly anesthetized rats (pentobarbital, 20 mg/kg) changed under the above conditions into prolonged depolarizations (HDs) which led to a substantial increase in animals' mortality (60%). The SDs evoked in the cortex and hippocampus of deeply anesthetized rats (pentobarbital, 50 mg/kg) showed that hippocampus became highly vulnerable by CO hypoxia. Duration of the SD-provoked HDs often reached 30-60 min after a single SD wave. Decreased cell density was found in CA1 area of the hippocampus 20-30 days after the CD-enhanced CO hypoxia. Cerebrolysin (2.5 ml/kg daily, during 10 days) prevented from severe hippocampal injury (formation of granulomas) usually seen in the left hemisphere of rats not treated with cerebrolysin.

Acute Disease↗