Residual effects of prolonged cannabis treatment on shuttle-box avoidance in the rat.

Chronic oral administration of cannabis extract to rats was examined for its residual effects on shuttle-box avoidance learning. In experiment 1 avoidance learning was assessed in rats that had been tested previously on other behavioral tests. Chronic treatment (3 months) facilitated the learning of shuttle-box avoidance in cannabis-treated animals relative to vehicle controls. In experiment 2 very similar results were obtained in naive rats. These and other residual effects of chronic cannabis treatment are similar to the effects of hippocampal lesions.

A blocking ELISA for detection of antibody to a subgroup-reactive epitope of African horsesickness viral protein 7 (VP7) using a novel gamma-irradiated antigen.

A novel gamma irradiated inactivated cell culture derived African horsesickness viral (AHSV) antigen was used in a blocking ELISA (B-ELISA) for detecting antibody to a subgroup-reactive epitope of AHSV. A monoclonal antibody (MAB), class IgM, against an epitope on African horsesickness (AHS) viral protein 7 (VP7) was developed in BALBc mice and used in the B-ELISA. The MAB, designated F9H, was blocked by 69 serums from equidae with antibody to AHS, but its binding activity was not appreciably affected by 301 serums that did not contain antibodies to AHS virus. An ELISA protocol using a blocking format is described.

Variable interval responding maintained by intravenous codeine and ethanol injections in the rhesus monkey.

Rhesus monkeys were trained to respond under a variable interval 2 min schedule for codeine or ethanol injections. Both codeine and ethanol were effective in the initiation of variable-interval responding; responding was maintained over a range of codeine (0.003-1.0 mg/kg/injection) and ethanol doses (32.0-560 mg/kg/injection). Maximum rates of responding were obtained at the 0.01 mg/kg/injection codeine dose (0.14 responses/sec) and at the 180 mg/kg/injection codeine dose (0.19 responses/sec). Rates of responsing were bitonic functions of the reinforcer dose for both codeine and ethanol; maximum rates were obtained at intermediate doses and lower rates occurred at the extremes of the dose range. Both codeine and ethanol showed within-session decreases in responding across the range of reinforcer doses. Codeine-reinforced responding declined in rate within the one-hour session without a similar change in the frequency of drug injection; in contrast, both ethanol-reinforced responding and the frequency of ethanol injections declined within each session across a range of doses. Increasing or decreasing the codeine dose half-way through the one-hour session resulted in increases or decreases in codeine responding compared to controls. These data indicate that the progressive decline in codeine-reinforced responding is not the result of a generalized disruption of responding.

Relative reinforcer magnitude under a nonindependent concurrent schedule of cocaine reinforcement in rhesus monkeys.

Lever pressing by three rhesus monkeys was maintained under a two-lever concurrent schedule of cocaine reinforcement. Responding on one lever (constant-dose lever) produced a constant dose of 0.05 or 0.1 mg/kg/injection arranged according to a variable-interval 1-min schedule. Responding on the other lever (variable-dose lever) produced a comparison dose of cocaine (0.013 to 0.8 mg/kg/injection), also under a variable-interval 1-min schedule. The two variable-interval schedules were made nonindependent by arranging that the assignment of a reinforcer by one schedule inactivated the second schedule until the assigned reinforcer had been obtained. This modification ensured that the two cocaine doses were obtained with approximately equal frequency, regardless of the distribution of the subject's responding. Preference, indicated by relative response frequency on the variable-dose lever, was almost always for the larger of the doses and was a monotonic function of the comparison dose, except at the highest doses. Preferences at the highest comparison doses may have resulted from the low overall response rates exhibited at these doses. Relative response frequencies on the variable-dose lever roughly matched relative reinforcer magnitude (mg/kg/injection available on the variable-dose lever divided by the sum of mg/kg/injections available on each lever).

M-mode ultrasonic detection of microbubbles following saturation diving: a case report and proposal for a new grading system.

An M-mode ultrasound system was used to obtain a reliable method for the evaluation of microbubbles caused by decompression. When the probe is focused in the outflow tract of the right ventricle it is easy to recognize a linear configuration of the echoes caused by the microbubbles. A quantitative study of microbubbles can be done by counting the number of linear echoes per second. Application of this method is reported following saturation diving decompression. We think the reported method is worthy of further use.

Decompression sickness with subsequent lymphatic manifestation following recompression treatment: a case report in a heavy drinker.

A case of decompression sickness is described in an uniformed diver who developed lymphatic manifestations after recompression treatment. No definite contributing factors to this rare disorder were established. A brief review of cutaneous lesions in decompression sickness is also presented.

Characteristics of the porcine kidney cell line IB-RS-2 clone D10 (IB-RS-2 D10) which is free of hog cholera virus.

A Brazilian stock of clone C17 of the IB-RS-2 porcine kidney cell line which was contaminated with hog cholera virus (HCV) was cloned. One clone designated IB-RS-2 D10 was determined to be free of HCV, 20 other viruses, and Mycoplasma. IB-RS-2 D10 cells possessed the same viral susceptibility pattern as the contaminated parent cells to the viruses of foot-and-mouth disease, swine vesicular disease, vesicular exanthema of swine, transmissible gastroenteritis, and several other viruses. The IB-RS-2 D10 cells had a median chromosome count of 34, were morphologically epithelioid cells, and were resistant to HCV infection. Freedom from HCV affords advantages for vaccine production and avoids laboratory contamination.