Detection and management of hypercoagulability

Patients at high risk of having thromboses can be identified not only on the basis of clinical criteria but also on the basis of laboratory studies. With use of a condensed coagulation profile consisting of six laboratory tests, the clinical impression of hypercoagulability can be confirmed in approximately 90 per cent of cases. Therapy directed to correct specific laboratory abnormalities may be more efficacious than nonspecific therapy.     

An open-label, noncomparative study to evaluate the efficacy, safety, and tolerability of azithromycin in the treatment of patients with acute sinusitis

The efficacy, safety, and tolerability of a 5-day, once-daily course of azithromycin were assessed in patients with acute sinusitis. Patients received two 250-mg capsules of azithromycin on day 1 and one 250-mg capsule on days 2 through 5. Of 102 clinically assessable patients, 27 (26.5%) were cured and 69 (67.6%) were improved on days 5 to 7. At days 12 to 16, 88 (86.3%) had a favorable clinical response. A total of 64 patients experienced adverse events; in all but two patients, adverse events were of mild or moderate severity. Thus azithromycin given once daily for 5 days was an effective treatment for patients with acute sinusitis.     

Hemodialysis access recirculation measured by ultrasound dilution

The most widely used clinical method for measuring recirculation in the access device is based on urea dilution. The three simultaneous blood samples required during hemodialysis interrupt the treatment, and results of chemical analysis are often delayed for several days. Alternatively, detecting recirculation by dilution of arterial blood caused by a bolus of normal saline injected into the venous blood line has several advantages. In this study, an ultrasound sensor clamped onto the arterial line entering the dialyzer was used to detect such dilution from a reduction in sound velocity observed in the saline diluted blood. Within the target range, the change in ultrasound velocity (ultrasound dilution) is linearly correlated with the dilution of whole blood by normal saline. The same sensor was also used to measure flow in the blood line using an established ultrasound transit-time method. During 34 hemodialyses in 28 patients, only 3 patients had detectable recirculation measured by ultrasound dilution. To further evaluate the sensitivity of the new method the dialysis lines were reversed during hemodialysis in the 25 patients with no recirculation. After this, all had detectable recirculation ranging from 10 to 60%. The mean error of duplicate measurements was 3.9 +/- 2.8%. Recirculation by ultrasound dilution correlated closely with recirculation measured by urea dilution (r = 0.9156, p < 001). The data suggest that the ultrasound dilution method is both sensitive and accurate. Ease of use and immediate availability of results added to the clinical usefulness of this method for evaluating the integrity of the hemodialysis access.     

Systematic comparison of the effects of hippocampal and fornix-fimbria lesions on acquisition of three configural discriminations

The effects of lesions to the hippocampal system on acquisition of three different configural tasks by rats were tested. Lesions of either the hippocampus (kainic acid/colchicine) or fornix-fimbria (radiofrequency current) were made before training. After recovery from surgery, rats were trained to discriminate between simple and compound-configural cues that signaled the availability or nonavailability of food when a bar was pressed. When positive cues were present, one food pellet could be earned by pressing a lever after a variable time had elapsed. The trial terminated on food delivery (variable interval 15 s). This procedure eliminates some possible alternative explanations of the results of previous experiments on configural learning. Hippocampal lesions increased rates of responding and retarded acquisition of a negative patterning task (A+, B+, AB-); using a ratio measure of discrimination performance these lesions had a milder retarding effect on a biconditional discrimination (AX+, AY-, BY+, BX-), and they had no effect on a conditional context discrimination (X: A+, B-; Y: A-, B+). Fornix-fimbria lesions did not affect acquisition of any of these tasks but increased rates of responding. The results suggest that several task parameters determine the involvement of the hippocampus in configural learning; however, all tasks tested can also be learned to some extent in the absence of an intact hippocampal system, presumably by other learning/memory systems that remain intact following surgery. The lack of effect of fornix-fimbria lesions on any of these tasks suggests that retrohippocampal connections with other brain areas may mediate hippocampal contributions to the learning of some configural tasks. An analysis of these results and of experiments on spatial learning situations suggests that involvement of the hippocampus is a function of the degree to which correct performance depends on a knowledge of relationships among cues in a situation.