Pressure Of Oxygen In Arterial Blood Research Articles

Inhibition of bacterial motility with human antiflagellar monoclonal antibodies attenuates Pseudomonas aeruginosa-induced pneumonia in the immunocompetent rat.

Two human monoclonal antibodies, directed against the type a and type b flagellar proteins of Pseudomonas aeruginosa, inhibited bacterial motility in vitro specifically and in a concentration-dependent manner. In order to determine if this decreased bacterial motility was associated with a decreased pathogenicity, the ability of these human antiflagellar monoclonal antibodies to attenuate P. aeruginosa-induced pneumonia in the rat was assessed. Incubation of P. aeruginosa with a 1:1 mixture of the human antiflagellar monoclonal antibodies prior to pulmonary instillation significantly (P < 0.05) ameliorated the bacterium-induced decrease in arterial blood oxygen pressure, blunted the increase in respiratory rate, and markedly reduced the area of pulmonary inflammation. Similarly, intravenous administration of the human antiflagellar monoclonal antibodies 1 h after pulmonary instillation of the bacteria also reduced the in vivo pathogenicity of P. aeruginosa. Therefore, human antiflagellar monoclonal antibodies can decrease the in vitro motility of P. aeruginosa and can reduce its in vivo pathogenicity when administered either before or after bacterial challenge.

Glucocorticoid response and adrenal lipid peroxidation in rats submitted to chronic hypobaric hypoxia.

The well known physiological changes that occur in adaptation to chronic hypobaric hypoxia (CHH) prevent the fall in arterial blood oxygen pressure below normal limits but neither the ventilatory nor the circulatory adaptation are able to maintain a normal capillary blood pO2. We report here our findings on adrenal histology, function, and lipid peroxidation in intact and castrated rats of both sexes submitted to twelve weeks of adaptation to 4,400 m simulated altitude. In the CHH rats hematocrit was increased; adrenal weight was increased in males and decreased in castrated females. Adrenal histology and histochemistry were normal. Corticosterone level and uric acid were unchanged except in castrated animals: corticosterone was decreased in males and increased in females. Uric acid was increased in castrated males, the only group in which adrenal lipid peroxidation was unaffected by castration. In the remaining groups, it was diminished compared to their intact controls. Intact normoxic males showed a significant direct correlation between plasmatic lipoperoxidation products (TBA-reactive substances) and uric acid (r = 0.961), which disappeared under hypoxia or with castration. Sex related differences were found in hematocrit and adrenal weight responses. The presence of androgens was involved in the adaptative response of cortical and reticular histometry, lipid peroxidation, and corticosterone level. These results do not support Selye's hypothesis of exhausted adrenal glands in chronic stages of adaptation and suggest that a proper relation between adrenal and gonadal steroids hormones is essential for systemic and tissular responses to diminished oxygen supply.

Brain metabolism in deep controlled hypotension in neurosurgical patients.

Changes in the lactate and pyruvate levels and lactic dehydrogenase activity in the cerebrospinal fluid were followed in 56 patients anaesthetised for neurosurgery. Mean arterial blood pressure (MAP) was reduced in these patients from about 90 to about 35 mm Hg. This allowed to safely place a clip at a brain artery aneurysm. In spite of deep hypotension, ischaemia described by other authors in such cases was never observed. Changes in lactate and pyruvate concentrations, lactate/pyruvate ratio and lactic dehydrogenase activity justify the conclusion that we were dealing with an undisturbed metabolism of the brain tissue. The levels of metabolic parameters, even when increased in hypotension, fell well within the range of physiological values. Attention is called to the fact that partial oxygen pressure in arterial blood during controlled hypotension was about 100 mm Hg, a value considered as limiting to oxygen metabolic transformation within the central nervous system in deep hypotension. We also suggest a different mechanism of passage of lactates and pyruvates through the blood-brain barrier.

Pulmonary edema associated with the use of betamimetic agents in preterm labor

A case report of pulmonary edema associated with the use of a betamimetic agent in preterm labor is reported. A 31-year-old, black multigravida woman, 28 weeks pregnant, was admitted to the hospital with dysuria, vaginal bleeding, and uterine contractions. She had experienced premature labor in her previous pregnancies, and she had a history of kidney stones, confirmed by pyelography, and repeated urinary tract infections. Eighteen hours after admission, the contractions were occurring every five minutes. Terbutaline sulfate constant infusion (10-20 micrograms/min) was started. By hospital day 2, the uterine contractions were occurring every 1-2 minutes and lasting 50 seconds. The terbutaline therapy was discontinued, and isoxsuprine hydrochloride infusion was started at 240 micrograms/min and gradually increased to 800 micrograms/min. The patient complained of smothering and became tachypneic after one hour and 40 minutes of therapy. The shortness of breath and tachypnea continued in spite of the administration of oxygen and positional changes. The isoxsuprine was discontinued. The diagnosis of pulmonary edema was confirmed by abnormal findings in the chest roentgenogram, bilateral rales, and a decrease in arterial blood oxygen pressure. A literature review of pulmonary edema associated with the administration of beta sympathomimetic drugs is presented, which suggests this adverse effect is multifactorial in origin. Precipitating factors may include corticosteroids, fluid overload, low levels of serum potassium, twin gestations, a sustained tachycardia greater than 140 beats per minute, undiagnosed cardiopulmonary disease, or catecholamine-induced cardiac injury. Patients requiring betamimetics for the delay of premature labor should be monitored closely to obviate this complication.

Psychosomatics: How your emotions can damage your health

Silver is used in a wide range of products, and during their production and use, humans may be exposed through inhalation. Therefore, it is critical to know the concentration levels at which adverse effects may occur. In rodents, inhalation of silver nanoparticles has resulted in increased silver in the lungs, lymph nodes, liver, kidney, spleen, ovaries, and testes. Reported excretion pathways of pulmonary silver are urinary and faecal excretion. Acute effects in humans of the inhalation of silver include lung failure that involved increased heart rate and decreased arterial blood oxygen pressure. Argyria—a blue-grey discoloration of skin due to deposited silver—was observed after pulmonary exposure in 3 individuals; however, the presence of silver in the discolorations was not tested. Argyria after inhalation seems to be less likely than after oral or dermal exposure. Repeated inhalation findings in rodents have shown effects on lung function, pulmonary inflammation, bile duct hyperplasia, and genotoxicity. In our evaluation, the range of NOAEC values was 0.11–0.75 mg/m3. Silver in the ionic form is likely more toxic than in the nanoparticle form but that difference could reflect their different biokinetics. However, silver nanoparticles and ions have a similar pattern of toxicity, probably reflecting that the effect of silver nanoparticles is primarily mediated by released ions. Concerning genotoxicity studies, we evaluated silver to be positive based on studies in mammalian cells in vitro and in vivo when considering various exposure routes. Carcinogenicity data are absent; therefore, no conclusion can be provided on this endpoint.

Survival Following Extreme Hypoxemia

A fall of arterial blood oxygen pressure (Pao2) to 20 mm Hg or less has generally been held incompatible with survival, but there are exceptions. We found survival in extreme hypoxemia to occur with a rate of more than one out of 1,700 hospital patients and it is especially likely in the presence of circulatory collapse. Permanent physiological impairment could not be identified when these patients were followed up for many months. Neither the degree of hypoxemia nor survival was well correlated with hydrogen ion or carbon dioxide levels. Evidence of severe neurological impairment did not preclude survival, and the neurological signs were reversible in most instances. Blood oxygen studies often reveal derangements not revealed by pH and carbon dioxide studies, and a low oxygen level should not be considered a sign of hopelessness.

Lactate-pyruvate ratio and its relation to oxygen pressure in arterial, coronarvenous and femoralvenous blood.

Lactate-pyruvate ratio and its relation to oxygen pressure in arterial, coronarvenous and femoralvenous blood.