FLUORESCENT CELL-COUNTING NEUTRALIZATION TEST FOR PSITTACOSIS

Hahon, Nicholas (Fort Detrick, Frederick, Md.), and Kenneth O. Cooke. Fluorescent cell-counting neutralization test for psittacosis. J. Bacteriol. 89:1465-1471. 1965.-A sensitive, precise, and specific serological procedure, the fluorescent cell-counting neutralization test, was developed to detect and to measure quantitatively psittacosis serum-neutralizing antibodies within 24 hr. The test is based on the reduction of fluorescent cells in McCoy cell monolayers resulting from the neutralization of infective agent particles by specific antiserum. Small but significant rises in neutralizing titers were measured in serum specimens from monkeys previously exposed to the psittacosis agent and from humans with diagnoses of subclinical or established psittacosis infections.

THE EFFECT OF MULTIPLE S-DELTA PERIODS ON RESPONDING ON A FIXED-INTERVAL SCHEDULE. II. IN A PRIMATE

A squirrel monkey was subjected to a fixed-interval pattern of reinforcement. During the course of each interval a bright white light was repeatedly presented. In the presence of the white light, a response was never immediately followed by food; the white light thus functioned as S(Delta). Responding was interrupted during the S(Delta) periods, but in the squirrel monkey as in the pigeon, these interruptions did not destroy the characteristic scalloped pattern of the cumulatively recorded responding through each interval.

RUBELLA COMPLEMENT FIXATION TEST

Complement-fixing antigens specific for rubella were made in tissue cultures of RK-13 rabbit kidney cells and primary cultures of kidney from the African green monkey. The antigens were prepared with the infected cell monolayer diluted to 30 percent with supernatant fluid and frozen and thawed three times. Complement-fixing antibody appeared in patients with rubella soon after the termination of rash and persisted for at least 8 months. In 8 out of 12 individuals who had the disease 10 to 20 years before they were tested, no complement-fixing antibody was found, but neutralizing antibody was present.

PERSISTENT BEHAVIOR MAINTAINED BY UNAVOIDABLE SHOCKS

Squirrel monkeys were trained on a multiple schedule in which 10-min periods on a continuous shock avoidance schedule, indicated by a yellow light, alternated with 10-min periods on a 1.5-min variable interval schedule of food reinforcement (VI 1.5). A white light indicated that VI 1.5 was in effect, except for the middle 2 min of the period on VI 1.5, in which a blue light appeared and terminated with the delivery of a 0.5-sec unavoidable shock. Stable response rates developed in the avoidance and VI 1.5 components. However, the highest response rates occurred in the blue, preshock stimulus. A series of experiments showed that responding in the blue stimulus persisted even when responding had been extinguished on both the VI schedule of food reinforcement and the shock avoidance schedule. Responding in the blue stimulus ceased when the blue stimulus terminated without shock or when it terminated with a response-contingent shock. Each time responding ceased, it was restored by terminating the blue stimulus with an unavoidable shock. When the blue stimulus was on throughout each session and unavoidable shocks were delivered at regular 10-min intervals, responding was well maintained. These results show that in monkeys that have been trained on a continuous avoidance schedule, unavoidable shocks can maintain responding even under conditions where responses have no programmed consequences.

CHARACTERISTICS OF AVERSIVE THRESHOLDS MEASURED BY A TITRATION SCHEDULE

Three variables were studied for their single and joint effects on aversive thresholds obtained by a titration schedule with electric shock as the aversive stimulus. One variable was the interval between the periodic increments in shock amplitude. Another was the size of this increment. The third was the size of the decrement produced when the subject responded. Both monkeys and humans tolerated more shock at the shorter increment-to-increment intervals than at the longer ones, confirming rat data previously obtained. Reducing the decremental step size also led to an increase in the amount of shock tolerated by monkeys. In addition, simply reducing both incremental and decremental step size without changing the interval between increments led monkeys to tolerate more shock. The attempt to explain these data was based on the changes that such manipulations might produce in the amount of avoidance behavior elicited.

ISOLATION OF ENTEROVIRUSES FROM THE "NORMAL" BABOON (PAPIO DOGUERA)

Fuentes-Marins, R. (Southwest Foundation for Research and Education, San Antonio, Texas), A. R. Rodriguez, S. S. Kalter, A. Hellman, and R. A. Crandell. Isolation of enteroviruses from the "normal" baboon (Papio doguera). J. Bacteriol. 85: 1045-1050. 1963.-In a study designed to determine whether the baboon (Papio doguera) would be suitable for use as a model of human virus infections, the normal enterovirus flora was determined. Five agents were isolated from 101 stool samples: four from the African group and one from the African-African group. None of the stool samples from the Domestic group of animals was found to contain any agents. On the basis of their biological characterizations (animal source, cytopathic effect, plaque formation, and antigenic relationships), the isolates were separated into two groups. Accordingly, prototype strains AA153 and A13 were designated for the African-African and African groups, respectively. These viruses have not been found to be related to any known human viruses. Their relationship to organisms isolated from other animals, especially primates, awaits study. The failure to detect latent viruses in preparations of baboon kidney cell cultures suggests a relatively "clean" animal which may be used with safety in preparation of vaccine for human administration.