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Chemical burns of the colon and rectum

From the experimental data obtained in 104 animals and clinical observation of 270 cases of digestive tract chemical burns the authors have found that in response to the effect of a corrosion substance, got into the stomach, a complex of protective secretory motor reactions preventing in the most cases from the injury to the intestinal tract occur. In contaminations incompatible with life only, a superficial burn of the colon associated with injuries to the upper portions of gastrointestinal tract, does occur. This was found at the analysis of 62 postmortem protocols of the cases who died ater taking some chemical liquids.     

The formation of blood system tolerance in rats to the repeated action of a stressor stimulus

Repeated immobilisation induced a biphasic dynamic of the blood system stress sensitivity: first, an increased neutrophilia, lymphocytopenia, bone marrow granulocyte depletion and activation of the erythropoiesis; second, a restitution of mature granulocyte-monocyte cells number in the bone marrow and accumulation of neutrophils in the spleen.     

Endogenous ascorbate regenerates vitamin E in the retina directly and in combination with exogenous dihydrolipoic acid

An in vitro neonatal rat preparation, consisting of the isolated caudal brainstem and stomach joined by the intact vagi, was developed using Sprague-Dawley rats. The animals were 0 to 4 days of age. This preparation provided an opportunity to investigate the extracellular and intracellular responses of neurons in the nucleus tractus solitarius (NTS) of the brainstem to electrical stimulation of subdiaphragmatic vagal fibers. The dorsal and ventral vagal branches were electrically stimulated at the point of the common subdiaphragmatic vagal trunk. The isolated preparation was superfused in a recording chamber at 28 degrees C with a modified Krebs solution, equilibrated with 95% O2 and 5% CO2. Suction microelectrodes, for electrical stimulation, were positioned on the common vagal trunk just below the diaphragm to evaluate extracellular and intracellular evoked responses in NTS. A total of 204 subdiaphragmatic vagally-evoked (SDVe) brainstem unitary responses in the NTS were recorded. The mean latency of the extracellular SDVe brainstem responses was 89 +/- 12.9 ms (mean +/- SD). The peripheral gastric effects of CCK-8 on SDVe unitary responses in NTS neurons were evaluated. The peptide caused a significant increase in the excitability of these NTS neurons which was blocked by the CCKA receptor antagonist L-364,718. Neurons in the NTS and the dorsal motor nucleus of the vagus which showed excitatory responses to vagal stimulation were filled with Lucifer Yellow to evaluate their morphology.     

Tensile strength and histological changes of abdominal aorta of malnourished rats

The resistance of the abdominal aorta of rats after 6, 7 and 8 weeks of malnutrition, compared with control animals, was evaluated by longitudinal tensiometry. Weakness of this vessel in malnourished rats was demonstrated; microscopic examination of the aorta stained by Masson, Calleja and hematoxylin-eosin methods showed a decrease in amorphous ground substance and an increase in the width of elastic laminae. There was no visible alteration either in the endothelial lining layer or in the smooth muscle fibers. Such alterations of the aorta are, to the authors' knowledge, the first reported modifications in the peripheral vasculature after malnutrition.     

The effect of cytochrome c preparations on the autoregulation of the cerebral blood flow in ischemia

The effect of animal cytochrome C (Ca), biotechnological cytochrome (Cb) and its hemtetradecapeptide (HTDP) on cerebral blood flow autoregulation during rapid decrease of systemic arterial pressure (SAP) was studied in acute experiments on rats. Cytochrome C preparations caused no effect on the autoregulatory responses of the cerebral vessels in animals with normal cerebral circulation. Injection of 5 mg/kg Ca and Cb and 0.8 mg/kg HTDP promoted restoration of the phenomenon of cerebral blood flow autoregulation in ischemic brain damage in change of SAP from 120 to 60 mm Hg. Prophylactic injection of 20 mg/kg Ca and Cb and 3.3 mg/kg HTDP prevented cerebral blood flow autoregulation disturbance caused by transitory brain ischemia.     

beta-Amyloid precursor protein fragments and lysosomal dense bodies are found in rat brain neurons after ventricular infusion of leupeptin

Infusion of the serine and thiol protease inhibitor, leupeptin, is known to cause a reduction of fast axoplasmic transport, and accumulation of lysosomal dense bodies in neuronal perikarya. We have found these dense bodies in hippocampal and cerebellar neurons contain ubiquitin conjugated proteins. We now demonstrate that these accumulated neuronal lysosomes are labeled by antisera to the cytoplasmic, transmembrane and extracellular domains of beta-amyloid precursor protein (APP) and also that lysosomal APP is fragmented. This in vivo model confirms that neurons can process APP via a lysosomal pathway and that neuronal lysosomes in vivo contain both N-terminal and potentially amyloidogenic C-terminal fragments of APP. We also show that increased APP immunoreactivity after leupeptin treatment is seen first in neurons and later in astrocytes. On recovery from infusion, APP N-terminal immunoreactivity diminishes whilst C-terminal reactivity remains in neurons. These findings are consistent with production in whole brain of potentially amyloidogenic fragments of APP within neuronal lysosomes in perikarya and dendrites implying that neurons may play a role in forming the beta-amyloid of plaques.