Fatal yew (Taxus sp) poisoning in Willamette Valley, Oregon, horses

Despite the well-founded reputation of plants of the genus Taxus as being amongst the most toxic plants for domestic livestock in the US, there are surprisingly few published case reports of yew poisoning in horses. This report documents 2 acute fatalities in horses in the central Willamette Valley, OR associated with the consumption of Taxus sp. The predominant features of the intoxication were peracute death, with no signs of struggling or convulsions, in otherwise fit and well managed adult horses. The most significant gross necropsy findings were limited to pulmonary congestion and hemorrhage, suggestive of acute circulatory disturbance. A diagnosis of Taxus sp poisoning was confirmed on the basis of a history of potential exposure, by the identification of yew leaves in the gastric contents of the horses, and by the subsequent identification of yew clippings in the pasture. The literature relevant to Taxus sp poisoning in horses is reviewed.

Age differences in problem-solving style: the role of emotional salience

Qualitative differences in problem-solving style for situations varying in emotional salience were examined among adolescents, young, middle-aged, and older adults. Participants wrote essays on how each of 15 problem situations should be resolved. There were minimal age differences for problem-focused strategies, with all age groups using this strategy the most. Age differences for problem-solving strategy were highly dependent on the degree to which the situation was emotionally salient. All individuals were more likely to use an avoidant-denial strategy in low emotionally salient situations and passive-dependent and cognitive-analysis strategies in high emotionally salient situations. However, older adults used both passive-dependent and avoidant-denial strategies more than younger age groups. Problem-focused strategies were used least in high emotionally salient situations. Implications of findings are discussed from an adult developmental perspective.

The effect of H2-receptor antagonist premedication on the duration of vecuronium-induced neuromuscular blockade in postpartum patients

The clinical duration of vecuronium was measured in two groups of postpartum patients undergoing elective tubal ligation. Ten patients received no premedication and ten others ranitidine 150 mg orally the morning of surgery. The mean duration of action of vecuronium was 57.2 +/- 9.9 min in the unmedicated patients and 54.0 +/- 12.9 min in the ranitidine treated patients. These values were significantly greater than the mean value for nonpregnant control patients (35.3 +/- 8.4 min) but indistinguishable from the mean value for cimetidine pretreated patients (63.0 +/- 17.6 min) reported previously. The combined results of the previous and present studies provide convincing evidence that the clinical duration of vecuronium-induced neuromuscular blockade is significantly longer in the postpartum patient and independent of cimetidine or ranitidine pretreatment.

Computer separation of unitary spikes from whole-nerve recordings

A practical and efficient off-line computer technique is described for automatically separating unitary waveforms from multiunit whole-nerve spike train data with no a priori knowledge about the number of units or their waveforms. The procedure requires two recording eletrodes which provide 3 measures on each putative unit: (1) peak-to-peak amplitude on the proximal channel, (2) amplitude on the distal channel, and (3) temporal offset (depends on conduction velocity) between proximal and distal spikes. On the basis of these 3 measurements, individual unitary spikes are automatically separated into clusters according to empirically-determined limits of variability. The results of the program are displayed in 3-D plots of the 3 measures on each unitary spike and in plots of superimposed waveforms from each cluster. These plots can be used to interactively correct clustering errors. The procedure is illustrated with a 1-min segment of spike train data recorded in vivo from the siphon nerve of a freely-behaving Aplysia. We routinely obtain about 10 relatively well-isolated units in such segments. By utilizing the average waveforms and conduction velocities for individual clusters, it may eventually be possible to separate unitary spikes from compound waveforms resulting from simultaneous of two or more units.

Effect of thymosin and lipopolysaccharide on murine lymphocyte cyclic AMP

The effects of thymosin and lipopolysaccharide (LPS) on cyclic AMP levels in lymphocytes were evaluated using three independent assays which included adenine prelabeling, protein kinase binding, and radioimmunoassay. All three assays proved to be both sensitive and accurate in assessing relative changes in lymphocytes after incubation in vitro with various agents. The assays confirmed that basal and stimulated levels of cyclic AMP depended on the origin of the lymphocyte population. Each of the three techniques demonstrated that pyrogen-free bovine thymosin fraction 5 did not elevate thymocyte cAMP levels. In contrast, it was found that lipopolysaccharide (lps) significantly elevated cAMP levels in both spleen and thymus lymphocytes. These studies indicate that assays for measuring the activity of thymic extracts in which the intracellular levels of cyclic nucleotides are a criterion for activity are only valid if the preparations are not contaminated with endotoxins.