Neurologic Evaluation of Infant and Adult Rats before and after Sciatic Nerve Blockade

Background: Only limited data exist comparing differences in sensory function and responses to neural blockade in infant and adult rats. Therefore, the authors sought (1) to compare baseline thermal, proprioceptive, and postural responses in infant, adolescent, and adult rats; and (2) to compare the effects of sciatic nerve blockade on thermal, proprioceptive, and postural responses in infant, adolescent, and adult rats.

Methods: Infant, adolescent, and adult rats were evaluated for proprioceptive, thermal, and mechanical nociceptive and motor function before and after sciatic blockade using a detailed neurologic examination.

Results: Mechanical and thermal nociception were present in all rats, starting from age 1 day. The withdrawal reflex latency to pinch was rapid at all ages, whereas that reaction to thermal stimulus depended on both age and temperature. In contrast, the tactile placing response and hopping response were absent at birth and developed completely during the first 10 days of life. The extensor postural thrust was absent in the first 2 weeks of life and developed variably during the first 50 days of life. Sciatic blockade duration is shorter in infant rats than in adult rats receiving the same dose per kilogram. A brief halothane general anesthetic at the time of sciatic injection in infant or adult rats does not alter the duration of blockade.     

Antioxidant and glutathione-related enzymatic activities in rat sciatic nerve

The present work tries to establish the antioxidant capacity of the peripheral nervous tissue of the rat, in terms of the enzymatic activities present in this tissue that either prevent the formation of activated species as the semiquinone radical (DT-diaphorase), protect against activated oxygen species (superoxide dismutase, glutathione peroxidase), conjugate natural toxic products or xenobiotics (glutathione S-transferases, especially the activity conjugating 4-hydroxy-nonenal), or complete the glutathione system metabolism (glutathione disulfide reductase, γ-glutamyl transpeptidase). All the activities studied are lower in this tissue than they are in liver, except for γ-glutamyl transpeptidase. The relevance of the results obtained and its possible relationship with different neuropathies is discussed. It is concluded that the peripheral nervous tissue is by far less protected than the liver against oxidative damage.     

Serum levels of alpha-tocopherol (vitamin E) in Parkinson's disease.

To elucidate the possible role of vitamin E in the pathogenesis of Parkinson's disease (PD), we compared serum levels of alpha-tocopherol (vitamin E), measured by high-performance liquid chromatography, and the vitamin E/cholesterol ratio of 42 Parkinson's disease (PD) patients using their spouses as the control group. The serum levels of vitamin E did not differ significantly between the groups (13.84 +/- 0.56 micrograms/ml for PD and 14.80 +/- 0.57 micrograms/ml for controls), nor did the vitamin E/cholesterol ratio (0.64 +/- 0.03 for both groups). There was no influence of antiparkinsonian therapy on vitamin E or the vitamin E/cholesterol ratio. Serum levels of the vitamin E and vitamin E/cholesterol ratio did not correlate with age, age at onset, scores of the Unified Parkinson's Disease Rating Scale or the Hoehn and Yahr staging in the PD group. These results suggest that serum vitamin E concentrations do not play a role in the pathogenesis of PD.     

Effects of low-dose propofol administration on central respiratory drive, gas exchanges and respiratory pattern

The effects of sedative-hypnotic doses of propofol on respiratory drive and pattern have not yet been extensively described. Repeated small boluses of propofol (0.6-0.3 mg.kg-1) were administered to ten ASA I patients undergoing carpal tunnel release using regional anaesthesia. Airway pressure, capnography and pneumotachography were continuously recorded. With respect to basal values, no significant variations of respiratory rate, minute volume, tidal volume, inspiratory and expiratory time, total expiratory cycle, Ti/Ttot, TV/Ti, P0.1, EtCO2 and blood gas analysis were observed. Low doses of propofol, to maintain conscious sedation of light sleep, have not been shown to cause respiratory depression.     

Coronary permeability and left ventricular function following thrombolytic therapy

We study 40 patients, 55 +/- 7 years old with acute myocardial infarction treated early by thrombolytic therapy (20 STK and 20 rt-PA). All patients were angiographically studied in the following conditions: 1) baseline, before initiating therapy. 2) Three hours after treatment. 3) Twenty four hours later. 4) Before discharge. The infarct related artery was patent 24 hours after treatment in 31 patients (78%); five of them were patent before treatment, and we observed an early reperfusion in 20 patients (57%) and late reperfusion in 6 patients (17%). The number of patients with angiographic evidence of intraluminal thrombus decreased progressively through conditions while the grade TIMI of coronary perfusion increased in the absence of reocclusion. Final regional wall motion of infarct related myocardial zones and their degree of recovery were significantly higher in recanalized patients, as compared with non-reperfused patients. Similarly, left ventricular functional recovery was higher in patients with antegrade of collateral flow to the infarct area, as compared with totally occluded patients.     

Pulmonary embolism.

Pulmonary embolism (PE) is an important health problem and often a major clinical challenge, not only because of the low specificity of its clinical manifestations but also because of the increasing number of medical circumstances that are risk factors for this illness and the importance of early identification, since prompt and appropriate treatment can decrease mortality from this disease by about 25%. In recent years research on PE has been extensive, directed mainly at trying to determine and characterize its risk factors, establish new clinical probability algorithms, develop new diagnostic methods and put existing ones into perspective, seek new therapeutic approaches (pharmacological and non-pharmacological), and above all establish protocols that can guide the clinician from the stage of clinical suspicion to measures to prevent recurrence. It was the authors' aim to review the most significant literature on this subject, in order to produce a text that reflects the state of the art concerning PE and that can be used as a guide in the clinical approach to this pathology.