Continuous and intermittent levodopa differentially affect basal ganglia function

The effects of continuous and intermittent levodopa treatment on behavioral and biochemical indexes of basal ganglia function were compared in rats with unilateral 6-hydroxydopamine lesions of the nigrostriatal dopamine pathway. Animals treated for 30 days with intermittent levodopa exhibited behavioral sensitization manifested by an enhanced rotational response to apomorphine; the rotational response of rats treated with an equivalent dose of levodopa by continuous infusion did not differ from that of saline-treated controls. Dopamine receptor up-regulation in the denervated striatum relative to the intact striatum was statistically significant for D1 but not D2 receptors: This asymmetry in dopamine receptor levels was diminished following intermittent levodopa treatment. Glutamic acid decarboxylase activity, modestly elevated in all groups in the denervated striatum relative to the intact striatum, increased substantially over control values bilaterally as a result of intermittent, but not continuous, levodopa treatment. These findings suggest a relation between the schedule of chronic levodopa administration and the development of behavioral sensitization, possibly as a consequence of alterations in neuronal systems located downstream from striatal dopamine receptors. The behavioral sensitization induced by chronic, intermittent dopaminomimetic treatment may serve as a model for motor fluctuations in Parkinson's disease.     

Lasers as tools for mycology.

Methods of preparing fungal samples for chemical analysis are briefly considered. The basic principles employed in laser microscopy are outlined. The applications of the technique to mycology and to plant biology are discussed. Such a method allows chemical information to be obtained on the same sample and permits the detection of 74 elements in the periodic system of Mendeleev from lithium (3) to uranium (92). The preparative procedures are evaluated according to general histochemical principles. This technique requires little specimen preparation and has the advantage of not requiring large masses of tissue.     

Study of allergenic fungi by means of a laser beam.

Laser microscopy was employed to detect some elements of Mendeleev's classification in allergenic moulds for humans. It permits the detection of 74 elements in the periodic system, from lithium (3) to uranium (92). This method requires little specimen preparation and has the advantage of not requiring large masses of tissue.     

Nitrogen-sparing effect of epidural administration of local anesthetics in colon surgery

A nitrogen-sparing effect of epidural anesthesia has been clearly demonstrated in gynecological and lower abdominal surgery. To determine if epidural anesthesia also has a protein-sparing effect during major upper or mid-abdominal surgery, postoperative nitrogen balance and 3-methylhistidine urinary excretion (an index of skeletal muscle protein catabolism) were measured for 6 days in 28 patients who had undergone colon resection for cancer with general anesthesia (N2O-O2-1% enflurane) either supplemented with low dose fentanyl plus intermittent systemic pentazocine for postoperative pain (n = 13), or the same general anesthetic plus epidural injection of either etidocaine 1% intraoperatively and bupivacaine 0.25% postoperatively (n = 8) or meperidine (n = 7) for 48 hr after skin incision. The cumulative 6-day nitrogen balance and the cumulative 3-methylhistidine urinary excretion were significantly less after epidural injection of etidocaine intraoperatively and bupivacaine postoperatively than in the two other groups. There was a significant correlation between the daily urinary excretion of 3-methylhistidine and the daily nitrogen balance in the three groups. This study suggests that in colon surgery, epidural analgesia with local anesthetics in the postoperative period improves nitrogen balance and this effect takes place partly in the muscle.