Search results for "HYPOXIA"
showing 10 items of 508 documents
Surgical procedure affects physiological parameters in rat myocardial ischemia: need for mechanical ventilation.
1999
Several surgical approaches are being used to induce myocardial ischemia in rats. The present study investigated two different operative procedures in spontaneously breathing and mechanically ventilated rats under sham conditions. A snare around the left coronary artery (LCA) was achieved without occlusion. Left lateral thoracotomy was performed in spontaneously breathing and mechanically ventilated rats (tidal volume 8 ml/kg) with a respiratory rate of 90 strokes/min at different levels of O2 supplementation (room air and 30, 40, and 90% O2). All animals were observed for 60 min after thoracotomy. Rats operated with exteriorization of the heart through left lateral thoracotomy while breat…
Nicotinamide exerts different acute effects on microcirculatory function and tissue oxygenation in rat tumors
1993
Abstract Purpose : Nicotinamide has been reported to preferentially radiosensitize tumor tissue, supposedly through a reduction in tumor hypoxia. This may occur as a result of nicotinamide-induced changes in tumor blood flow and therefore the present study was undertaken to evaluate the effect of nicotinamide on circulatory parameters in skeletal muscle and tumor tissue (subcutaneously-implanted DS-sarcomas) of the rat. Methods and Materials : Mean arterial blood pressure (measured in the common carotid artery using a pressure transducer) and red blood cell flux (as measured by laser Doppler flowmetry) were continuously monitored for 120 min following a single intraperitoneal application of…
Regulation of free choline in rat brain: dietary and pharmacological manipulations.
1998
The present study analyses, comparatively, the kinetics of free choline in the brain of rats during dietary and pharmacological manipulations. Low-choline diet halved the choline plasma level but did not cause significant changes of CSF choline. High-choline diet, hypoxia and treatment with nicotinamide increased brain choline availability through a central site of action and increased the CSF choline concentration. CSF choline concentrations were more effectively elevated by nicotinamide treatment (20-25 microM) than by acute choline administration (13-15 microM). Increases of CSF choline, due to brain choline mobilization, were consistently associated with a net release of choline from th…
Phase ia/ii, two-arm, open-label, dose-escalation study of oral panobinostat administered via two dosing schedules in patients with advanced hematolo…
2013
Panobinostat is a potent oral pandeacetylase inhibitor that leads to acetylation of intracellular proteins, inhibits cellular proliferation and induces apoptosis in leukemic cell lines. A phase Ia/II study was designed to determine the maximum-tolerated dose (MTD) of daily panobinostat, administered on two schedules: three times a week every week or every other week on a 28-day treatment cycle in patients with advanced hematologic malignancies. The criteria for hematologic dose-limiting toxicities differed between patients with indications associated with severe cytopenias at baseline (leukemia and myeloid disorders) and those less commonly associated with baseline cytopenias (lymphoma and …
Hypoxyradiotherapy: lack of experimental evidence for a preferential radioprotective effect on normal versus tumor tissue as shown by direct oxygenat…
1998
Abstract Aim : In order to investigate possible pathophysiological mechanisms underlying the postulated preferential protective effect of hypoxia on normal tissue during radiotherapy, the impact of acute respiratory hypoxia (8.2% O 2 + 91.8% N 2 ) on tissue oxygenation was assessed. Methods : Tumor and normal tissue oxygenation was directly determined using O 2 -sensitive electrodes in two experimental rat tumors (DS and Yoshida sarcomas) and in the normal subcutis of the hind foot dorsum. Results : During respiratory hypoxia, arterial blood O 2 tension (pO 2 ), oxyhemoglobin saturation and mean arterial blood pressure decreased. Changes in the arterial blood gas status were accompanied by …
Deregulation of E2-EPF Ubiquitin Carrier Protein in Papillary Renal Cell Carcinoma
2011
Molecular pathways associated with pathogenesis of sporadic papillary renal cell carcinoma (PRCC), the second most common form of kidney cancer, are poorly understood. We analyzed primary tumor specimens from 35 PRCC patients treated by nephrectomy via gene expression analysis and tissue microarrays constructed from an additional 57 paraffin-embedded PRCC samples via immunohistochemistry. Gene products were validated and further studied by Western blot analyses using primary PRCC tumor samples and established renal cell carcinoma cell lines, and potential associations with pathologic variables and survival in 27 patients with follow-up information were determined. We show that the expressio…
Methemoglobinemia Associated with Late-Onset Neonatal Sepsis: A Single-Center Experience
2019
Objective Methemoglobinemia (MetHb) is a rare congenital or acquired cause of infantile cyanosis. We examined the role of MetHb in a neonatal intensive care unit (NICU). Study Design A retrospective observational study was conducted reviewing blood gas analyses of hospitalized newborns over a 2-year period. MetHb-positive patients (MetHb >1.8%) were matched with a control group for gestational age, weight, disease, and illness severity at admission. Maternal, neonatal, clinical, and laboratory parameters were collected and analyzed in both groups. Results MetHb incidence was 6%. The mean MetHb in the case group was 7.2%, and the first positive samples were observed at a mean of 22 days …
Noninvasive Ventilatory Assistance During Exercise for Patients with Kyphoscoliosis
2007
The goal was to determine whether noninvasive ventilatory assistance (NIV) could facilitate exercise performance and benefit physiologic parameters for eight hypercapnic kyphoscoliosis patients using a cycloergometer for 6-min periods at a constant power (20 W). The exercise protocols were performed in random order while breathing unaided (spontaneous breathing test or SBT) and also while receiving NIV (NIV test or NIVT). The NIV was pressure support (15 cm H2O) plus positive end expiratory pressure (PEEP) (4 cm H2O) via a nasal mask. Of the compared parameters, heart rate was not significantly different, but acidosis (pH = 7.32 +/- 0.04 vs. 7.36 +/- 0.04), hypoxia (PaO2 = 61.5 +/- 15.9 vs.…
Increased Hypoxic Tolerance by Chemical Inhibition of Oxidative Phosphorylation: “Chemical Preconditioning”
1997
A short ischemic episode preceding sustained ischemia is known to increase tolerance against ischemic cell death. We report early-onset long-lasting neuroprotection against in vitro hypoxia by preceding selective chemical inhibition of oxidative phosphorylation: “chemical preconditioning.” The amplitude of CA1population spikes (psap) in hippocampal slices prepared from control animals (control slices) was 31 ± 27% (mean ± SD) upon 45-min recovery from 15-min in vitro hypoxia. In slices prepared from animals treated in vivo with 20 mg/kg 3-nitropropionate (3-np) 1–24 h prior to slice preparation (preconditioned slices), psap improved to 90 ± 15% (p < 0.01). Posthypoxic oxygen free radical…
Prognostic implications of arterial blood gases in acute decompensated heart failure
2010
The prognostic value of arterial blood gases (ABG) in patients with acute decompensated heart failure (ADHF) is not well-established. We therefore conducted the present study to determine the relationship between ABG on admission and long-term mortality in patients with ADHF.We studied 588 patients consecutively admitted to our department with ADHF. ABG and classical prognostic variables were determined at patients' arrival to the emergency department. The independent association among the main variables of ABG (pO2, pCO2 and pH) and mortality was assessed with Cox regression analysis.At a median follow-up of 23months, 221 deaths (37.6%) were registered. 308 (52.4%), 54 (9.2%) and 50 (8.5%)…