Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During osmolality measurement by the vapor pressure method, exposure of the blood sample to air lowers the blood CO2 content and hence osmolality. A modification of the sample holder of a vapor pressure osmometer is described allowing exposure of the blood sample to a gas mixture with known concentration of CO2 and O2 while inside the closed sample chamber. This restores its CO2 content and hence osmolality. Data are presented comparing the unmodified and modified vapor pressure method with the freezing point depression method. A table was prepared for further correction of osmolality in case the blood's PCO2 differs from that of the gas mixture.
 ...
PMID:Correction for loss of CO2 from blood during measurement of osmotic pressure. 63 20

Acute alterations in plasma bicarbonate concentration have minimal effects on intracerebral pH and cerebral blood flow, perhaps due to blood-brain barrier mechanisms. To test this hypothesis, the consequences of an acute rise in the plasma bicarbonate concentration were studied in anesthetized rats previously subjected to an acute pressure pulse in the carotid system with unilateral damage to the blood-brain barrier. In rats subjected to a "heavy" hypertensive insult, the hemisphere on the side of the lesion showed a lactic acidosis, edema, and a depression of cerebral blood flow. An increase in the plasma bicarbonate concentrations of 15--20 mEq/1 during 35 minutes provoked a marked rise in the total CO2 content of this hemisphere, and a further increase in the lactate concentration, but did not later the brain edema nor affect further the already very low cerebral blood flow. An increase in the lactate concentration and a decrease of cerebral blood flow in the "reference" hemisphere indicated that the lesion was not completely unilateral. In rats subjected to a "moderate" hypertensive insult the changes were less pronounced and statistically not significant for all the parameters. There results illustrate the importance of an intact blood-brain barrier for the maintenance of intracerebral pH in the face of acute alterations in plasma [HCO3]. The impaired cerebral blood flow after an acute hypertensive insult did not appear to be influenced by the intracerebral [HCO3].
 ...
PMID:Effect of non-respiratory alkalosis on brain tissue and cerebral blood flow in rats with damaged blood-brain barrier. 67 46

Bartoli et al. (1974) found in dogs with constant PaCO2 that an increase in PCO2 in the vascularly isolated lungs increased ventilatory drive by a vagal reflex. We have examined the range of lung PCO2 over which the reflex operates. In anaesthetized dogs we ventilated the lungs separately with O2, maintaining gas exchange with the right lung. When we occluded the left pulmonary artery, left lung PCO2 fell to 2--4 mm Hg, and phrenic nerve firing decreased significantly. Phrenic activity increased again when left lung PCO2 was raised in steps to 19, 32 and finally to 50 mm Hg. PaCO2 was unchanged. Phrenic responses were abolished by cutting the left vagus nerve or by cooling it to 7--8 degrees C. The largest increase in phrenic activity occurred when left lung PCO2 was increased from 2 to 19 mm Hg, and the smallest when PCO2 was raised from 32 to 50 mm Hg. Hence the significance of the pulmonary-CO2 ventilatory reflex may lie in depression of ventilatory drive when pulmonary CO2 falls below normal, rather than in stimulation of breathing when pulmonary CO2 increases above normal.
 ...
PMID:I. Pulmonary-CO2 ventilatory reflex in dogs: effective range of CO2 and results of vagal cooling. 70 74

Chemical control of breathing was studied before and after the administration of the daily dose of methadone in 14 former heroin addicts who were enrolled in a methadone maintenance program and taking 60 to 100 mg/day. Two major groups were identified: group 1 in which subjects (n=6) had taken the drug for less than two months, and group 2 in which the subjects (n=6) had taken the drug from eight to 43 months. Prior to the daily dose of methadone, the levels of arterial carbon dioxide tension were significantly higher and ventilatory response to hypoxia significantly lower in group 1 than in group 2. Ventilatory responses to carbon dioxide (CO2) were also lower in group 1, but the difference was not statistically significant. Following the daily dose of methadone, the subjects in group 1 manifested significant reductions of ventilation and arterial oxygen tension, significant increases in arterial carbon dioxide tension and significant depressions of ventilatory responses to both CO2 and hypoxia in comparison to values before the administration of methadone. In contrast, subjects in group 2 manifested only a significant decrease in ventilatory responsiveness to hypoxia with no change in ventilation, arterial blood gas tensions or ventilatory responsiveness to CO2 following the daily dose. Two intermediate subjects (five and seven months) behaved as long-term subjects with regard to arterial carbon dioxide tension and CO2 responses but as short-term subjects with regard to responsiveness to hypoxia. Thus, during the first two months of methadone maintence, there is continual alveolar hypoventilation due to depression o both central (CO2) and peripheral (hypoxia) chemoreception. After five months, alveolar hypoventilation is abolished as the CO2-sensitive chemoreflex acquires full tolerance to methadone at the maintenance dose level. In contrast, tolerance of the hypoxia-sensitive chemoreflex is developed more slowly and is never complete.
 ...
PMID:Control of breathing during methadone addiction. 84 54

The effect of dietary vitamin E on lipid synthesis from U-14 C-D-glucose and 1-14C-acetate was studied in rat lungs in vitro. One-month-old Sprague-Dawley male rats were fed either a basal vitamin E-deficient diet or one supplemented with 45 ppm vitamin E ad libitum for two months. Glucose oxidation to CO2 by lungs was significantly (p less than 0.05) decreased by the exclusion of vitamin E from the diet. Oxidation of acetate to CO2 was not affected by the presence of vitamin E in the diet. The extent of labeled carbons from both glucose and acetate incorporated into total lipids was significantly lower in the lungs of vitamin E-deficient animals than in those of the supplemented group. However, the relative amounts of phospholipids, neutral lipids are free fatty acids in total lipids, and of glyceryl moiety and fatty acids in total lipids and in phospholipid fraction were not significantly altered by the status of dietary vitamin E. The results suggest a general depression of lipid synthesis in the lungs of vitamin E-deficient rats.
 ...
PMID:Effect of dietary vitamin E on lipid synthesis by rat lung in vitro. 84 45

The effect of respiration on the cerebrovascular response to elevated intracranial pressure (ICP) was studied in anesthetized dogs. Total and regional cerebral blood flows were measured using labelled microspheres. In spontaneously breathing dogs total and regional cerebral blood flows increased when cerebral perfusion pressure was reduced to 20 mm Hg. The increase in regional flows was greater in the infratentorial areas than in the supratentorial areas. The increase in cerebral flow in spontaneously breathing dogs was associated with the development of hypoxemia and respiratory acidosis secondary to depression of ventilation. Elevation in ICP while regulating PO2, PCO2, and pH by controlled ventilation resulted in decrease in the total and regional cerebral blood flows. The decrease in regional flows was greater in the supratentorial areas. Induction of respiratory acidosis during elevated ICP in the controlled ventilated dogs with a 5% CO2 in air gas mixture, reversed the decrease in cerebral flows. The results suggest that the increase in cerebral blood flow during elevated ICP in spontaneously breathing dogs is secondary to the development of hypoxemia and respiratory acidosis since cerebral vessels retain responsiveness to increased PaCO2 when the vessels are dilated due to elevated ICP. The results also indicate that the regional cerebrovascular response to elevated ICP is non-uniform.
 ...
PMID:Respiratory influence on the total and regional cerebral blood flow responses to intracranial hypertension. 84 90

The purpose of this investigation was to determine the value of ventilatory measurements and Apgar score in the diagnosis of respiratory depression in the newborn infant. The following were the results of the determinations made in 24 neonates whose mothers had received meperidine in a total dose up to 3 mg/kg within three hours prior to delivery; Respiratory rate, 51+/-3.7/minute; tidal volume, 21.4 +/- 1.5 ml; minute ventilation, 339 +/- 24 ml/kg X minute; end tidal CO2, 40.8 +/- 1.3 mm Hg; ventilatory response to CO2, 21.8 +/- 2.7 ML/KG X minute X mm Hg PACO2. The mean Apgar score was 7.1 and 9.0 at 1 and 5 minutes, respectively. None of the determinations were indicative of respiratory depression with the exception of the slope of the CO2 response curve; it was considered to be below the normal range. No correlations existed between the CO2 response curve and any other values. It is concluded that meperidine administered to mothers in labor in the described dose will not significantly alter Apgar score, VE, VT, RR, AND PAco2 in the newborn infant. The extent of respiratory center depression could be determined only by the decreased ventilatory response to CO2.
 ...
PMID:Respiratory depression at birth--value of Apgar score and ventilatory measurements in its detection. 87 Jun 60

Enflurane anesthesia with thiamylal induction in the dog produced only slight, statistically insignificant, changes in the heart rate and the mean systemic blood pressure. A significant depression of the respiratory rate with an associated significant increase in the arterial partial pressure of CO2 was produced, accompanied by a decrease in the blood pH. Progressive drop of the body temperature occurred throughout anesthesia. Significant hematologic changes included a reduction in the packed cell volume and the erythrocyte and leukocyte counts. The only significant change in the blood chemistry was an increase in alkaline phosphatase at 24 and 48 hours after induction of anesthesia.
 ...
PMID:Physiologic changes in the dog anesthetized with thiamylal and enflurane. 87 63

Multiple serum chemical values were examined in 92 patients with chronic glaucoma who were treated with the carbonic anhydrase inhibitors (CAIs) acetazolamide or methazolamide, seeking relationships between serum composition and symptomatic side effects. Of the 92 patients, 44 complained of a symptom-complex of malaise, fatigue, weight loss, depression, anorexia, and loss of libido, which we have found most commonly to threaten continuation of therapy. Patients who had this symptom complex were significantly more acidotic than those without it. Ten of 24 patients who had chemical evidence of excessive acidosis reported a dramatic alleviation of symptoms when sodium bicarbonate was administered, although their serum CO2-combining power changed little. There was no correlation of the symptom complex with serum potassium concentration, except in a few patients who were simultaneously receiving chlorothiazide diuretics for systemic hypertension and who became frankly hypokalemic.
 ...
PMID:Carbonic anhydrase inhibitor side effects. Serum chemical analysis. 88 13

The ventilatory response to CO2 was subdivided into that portion due to increasing rib cage expansion, and that due to increased diaphragmatic descent. Five children were studied, awake, and anesthetized with halothane, 0.8-0.9%. During anesthesia there was a 67+/-8% reduction (mean+/-SE) in the slope of the response of overall ventilation to an increase in CO2. This was primarily due to an 89+/-8% reduction in the recruitment of rib cage ventilation (P less than .001). There was no significant change in the slope of the diaphragmatic response (anesthetized value 19+/-21% less than control), although the response curve was shifted to the right so that a higher CO2 concentration was needed to stimulate a given level of diaphragmatic excursion. Additional measurements of the inspiratory intercostal electromyogram in three adult subjects documented a rapid, profound depression of intercostal activity with halothane anesthesia that was associated with a marked decrease in rib cage ventilation. The authors conclude that a major component of the ventilatory depression associated with halothane anesthesia results from the preferential suppression of intercostal muscle function with relative sparing of diaphragmatic activity.
 ...
PMID:Contributions of changing rib cage--diaphragm interactions to the ventilatory depression of halothane anesthesia. 90 May 41


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>