Ibuprofen protects rat livers from oxygen-derived free radical-mediated injury after tourniquet shock

Rats subjected to tourniquet shock suffer a severe form of circulatory shock, tissue and organ oxidative stress, and final multiple system organ failure (MSOF) and death of the animals within 24 h of tourniquet release. The oxidative damage observed in hind-limb muscle tissue after reperfusion does not by itself account for the final systemic and lethal MSOF. We have postulated that organ failure has its genesis in a primary perfusion abnormality, e.g. the hind limbs, which is followed by secondary hypoperfusion of other organs, such as the liver, as has been shown to be the case in several septic shock models. It has also been shown that injured or necrotic tissue can activate neutrophils, Küpffer cells, platelets, and both the complement and coagulation cascades. In turn, complement activation also leads to neutrophil and Küpffer cell activation as assessed by their capacity to generate oxyradicals. Herein we have evaluated the potential protective effect of ibuprofen on hepatic oxygen-derived free radical production, as well as its effects on both polymorphonuclear leucocyte (PMN) activation and liver infiltration. The protective effect of ibuprofen on hepatic oxidative injury was assessed by determining total thiol groups (SH), thiobarbituric acid-reactive substances (TBARS), and by the release of aspartic acid (AsT) and alanine (AIT) aminotransferases in control animals, in animals subjected to 5 h of tourniquets, and in animals after 2 h of hind-limb reperfusion. Liver infiltration by PMNs was determined by histology after staining with eosin-hematoxylin, and PMN activation by their capacity to reduce nitro blue tetrazolium (NBT).(ABSTRACT TRUNCATED AT 250 WORDS)

Estimation of ventilatory reserve by stair climbing. A study in patients with chronic airflow obstruction

Clinicians and surgeons have used the subjective response to the climb of "one or two flights of stairs" to assess the "reserve" of patients with chronic airflow obstruction (CAO). Very little objective data exist regarding the metabolic and ventilatory cost for any level of stair climbing in these patients. Therefore, this study was designed to evaluate the use of symptom-limited stair climbing as a simple method to estimate the peak oxygen uptake (VO2) and minute ventilation (VE) in patients with CAO. We studied 31 men with varying degrees of CAO, who climbed stairs until they stopped at their symptom-limited maximum. During this climb, timed expired gas was intermittently collected and analyzed, and oxygen saturation and heart and respiratory rates were recorded. The patients achieved 81 +/- 14 percent of their predicted maximal heart rate and 90 +/- 27 percent of their predicted maximal VE. The number of steps or flights climbed correlated linearly with peak VO2 (r = 0.72, p < 0.01) and with VE (r = 0.7, p < 0.01). Stair climbing peak VE, VO2, heart and respiratory rate correlated well with those achieved during standard leg cycle ergometry. The mean +/- SD number of flights climbed was 4.2 +/- 1.7 with most patients (87%) reaching at least 3 flights (54 steps). The group of eight patients with very severe CAO (FEV1 < 0.9 L) climbed 3.4 +/- 0.9 flights (61 +/- 16 steps). We conclude that a symptom-limited maximal stair climb helps estimate peak VO2 and VE in patients with CAO. The frequently advocated test to climb one to two flights to evaluate cardiopulmonary reserve is not adequate for most patients with CAO. Symptom-limited maximal stair climbing is a simple, inexpensive and readily available test that may be used to evaluate the cardiopulmonary reserve of stable patients with CAO.

Transtracheal delivery of gas decreases the oxygen cost of breathing

Transtracheally administered gases decrease inspired minute ventilation in both dogs and humans. To test if this is associated with a decrease in the oxygen cost of breathing and to evaluate subsequent changes in the breathing pattern, we studied five patients with chronic respiratory diseases while they spontaneously breathed air and different flows of tracheally administered gases. In a blinded crossover design, the gas consisted of either oxygen or air at 2, 4, and 6 L/min. Oxygen cost of breathing was estimated by the calculation of pleural pressure-time index (PPTI). The pattern of breathing was evaluated utilizing the tension time index for the diaphragm (TTdi). There were significant decreases in PPTI when the patients received 2, 4, and 6 L/min of transtracheal oxygen or air. TTdi also decreased as gas flow increased. This drop was significant at 6 L/min flow for both gases. We conclude that transtracheally administered gas reduces the oxygen cost of breathing. It also changes the respiratory pattern of the diaphragm to a less demanding pattern. This may offer an alternative form of treatment to rest overworked respiratory muscles.

Hypothyroidism and pleural effusions

Serous effusions have been thought to be an unusual complication of hypothyroidism and most commonly have been associated with ascites, pericardial fluid and heart failure. Pleural fluid as an isolated finding in hypothyroidism is apparently rare and complete analysis of these hypothyroid-associated pleural effusions has not been described. To determine the frequency, chemical characteristics and clinical associations of hypothyroidism and pleural effusions, the medical records of 128 patients with hypothyroidism (defined by an increased serum TSH concentration) were reviewed. The majority of effusions in patients with hypothyroidism were due to other diseases. Effusions solely due to hypothyroidism appeared to be a real entity. These effusions were borderline between exudates and transudates and showed little evidence of inflammation.

Cocaine exposure among children seen at a pediatric hospital

The results of 1,680 consecutive urine and serum toxicologic screens from 1,120 patients, performed in a children's hospital during a 19-month period were surveyed. Among this sample, 52 (4.6%) patients had specimens that contained cocaine and/or metabolite. Fifteen specimens contained ethanol, a benzodiazepine, or a narcotic in addition to cocaine. Four patients were neonates, whereas three were infants from 1 to 7 months of age. The remaining 45 patients were adolescents with a mean age of 19 years. Among the adolescents, 11 had a significant chronic illness. In 19 patients (37%), cocaine exposure was unsuspected until the results of testing for toxic substances were known. The reasons for hospital evaluation included depression/attempted suicide in 19 patients, seizure in five, chest pain in 5, motor vehicle accident in three, syncope in three, abdominal pain in two, pneumomediastinum in two, accidental self-immolation in one, and apnea in one. Twenty patients required medical hospitalization for a total of 268 patient-days. One patient, a neonate, died. There is a striking prevalence of cocaine exposure in the pediatric age group. Among adolescents, this exposure may occur despite the presence of chronic illness. Although the age distribution appears bimodal, infants and young children may also have unsuspected exposure to this toxin. Greater awareness of cocaine exposure in childhood will be needed by primary and tertiary care pediatricians to identify affected children and provide appropriate intervention.

The actions of phenol and pentachlorophenol (PCP) on axonal conduction, ganglionic synaptic transmission, and the effect of pH changes

1. A comparison of phenol, pentachlorophenol (PCP) and procaine effects on axonal conduction were studied in vitro in the sciatic nerves of toad. PCP and procaine were respectively 6.3 and 3.15 times more potent than phenol in blocking axonal conduction. 2. Effects of PCP on synaptic transmission were studied in vitro in the eighth sympathetic ganglion of toad. 3. Axonal conduction block and synaptic transmission block by phenol was reversible, but not that by PCP. 4. When the PCP ionization was increased, a lesser per cent reached the site of action, reducing its capacity to block the axonal conduction and ganglionic transmission. 5. PCP plus, 3,4-Diaminopyridine (3,4-DAP) decreased synaptic transmission block from post-ganglionic compound action potential (CAP) responses to supramaximal preganglionic stimulation.

The effects of hemicholinium-3 (Hc-3) during tetanic (TP) and posttetanic potentiation (PTP) on sympathetic ganglion

An electrophysiological analysis has been made of the synaptic plasticity in the eighth sympathetic ganglion of the toad. The mean amplitude of Compound Action Potential (CAP) recorded extracellularly was taken as a measure of the synaptic transmission. Repetitive stimulation of the preganglionic axonal fibers at 50 Hz for 40 seconds in the presence of Hc-3 led to facilitatory and depressant actions on ganglionic synaptic transmission. Hc-3 in the presence of elevated extracellular Ca2+ concentration (5.4 mM) increased Tetanic Potentiation (TP) and Posttetanic Potentiation (PTP) on eighth sympathetic ganglion. Hc-3 plus 3,4-diaminopyridine (3,4-DAP) increased synaptic transmission, TP, and PTP from postganglionic CAP responses to supramaximal preganglionic stimulation.