Alcohol septal ablation through an anomalous right coronary septal perforator: first report and discussion.

Alcohol septal ablation has become an acceptable alternative to surgical myectomy in patients with hypertrophic obstructive cardiomyopathy who meet strict clinical and anatomic criteria. While the first septal perforator arising off the left anterior descending artery is the typical conduit for alcohol septal ablation, patients with hypertrophic cardiomyopathy and severe septal hypertrophy may present with unusual septal perforator anatomy, including anomalous origin. We present the case of a patient in whom the dominant basal septal perforator arose anomalously off the proximal right coronary artery.

Immunological analyses of U.S. Space Shuttle crewmembers.

We have previously reported changes in the immunoresponsiveness of "T" lymphocytes following space flight. Additional data collected before and after 11 Shuttle space flights show that absolute lymphocyte numbers, lymphocyte blastogenic capability, and eosinophil percent in the peripheral blood of crewmembers are generally depressed postflight. These responses resemble those associated with physical and emotional stress and may not be related to flight per se.

[Human cellular immune responsiveness following space flight].

Peripheral circulating lymphocytes were separated from astronaut blood samples 3 times before and 2 times after the first four US Space Shuttle flights. The ability of the in vitro T lymphocytes to respond to phytohemagglutinin by blastogenesis was found to be reduced for each crewmember following spaceflight. In addition, the astronauts experienced a postflight increase in neutrophils and a decrease in eosinophils.

Human cellular immune responsiveness following space flight.

Peripheral circulating lymphocytes were separated from astronaut blood samples three times before and two times after the first four US Space Shuttle flights. The ability of the in vitro T lymphocytes to respond to Phytohemagglutinin by blastogenesis was found to be reduced for each crewmember following spaceflight. In addition, the astronauts experienced a postflight increase in neutrophils and a decrease in eosinophils.

Stomatocytosis in a colony of captive squirrel monkeys (Saimiri sciureus).

Chronic stomatocytosis, which increased in severity as a function of the time that animals were held in captivity, was observed in a small colony of squirrel monkeys. The stomatocytosis was associated with increasing hematocrits possibly due to a change in packing characteristics of the erythrocytes rather than any overt changes in the erythrocyte mass. Reticulocytes remained at control levels throughout development of the stomatocytosis.

Response-produced timeouts under a progressive-ratio schedule with a punished reset option.

Three behavioral options were available to food-deprived pigeons: (1) pecking one key resulted in food reinforcement according to a 50-response progressive-ratio schedule, (2) pecking a second key reset the progressive-ratio schedule to the initial progressive-ratio step, and (3) pecking a third key produced a 3-min timeout period. Pecks on the reset key were shocked. Under low and intermediate shock intensities, timeouts were not produced; under high shock levels, timeouts were produced regularly.

Self-imposed timeouts under increasing response requirements.

Self-imposed timeouts by pigeons working under a progressive-ratio food schedule were studied under different conditions. The main findings were (1) continued production of timeouts over an extended series of sessions, (2) more frequent responding on the key with the timeout consequence than on a key having no consequence, (3) an inverse relationship between number of timeouts and level of body weight, (4) production of timeouts when the timeout duration was brief, lengthy, or controlled by the pigeon, and (5) dependence of self-imposed timeouts on variables controlling responding under the progressive-ratio schedule. Under all experimental conditions, with the exception of performances at the high body weight, timeouts were more frequent during the longer progressive-ratio steps and usually were localized in the post-reinforcement pause or the early part of the step.

Variable location of punishment in a response sequence.

Key pecking of pigeons under a fixed-ratio 100, grain reinforcer schedule was followed by electric shock occurring once in each sequence of 100 responses with the shocked response varying irregularly in successive sequences. Under this shock schedule, a localized suppression of responding in a response sequence was not correlated with the probability of shock at different points in the sequence. High shock levels increased the duration of post-reinforcement pauses and suppressed responding during the first half of the response sequence.

Preference for locus of punishment in a response sequence.

Food-deprived pigeons pecked a key under a schedule in which grain was made available after the seventieth peck. In each sequence of 70 responses, either the first, middle, or final response was followed by electric shock. Before the first response of each sequence, each response on a second key changed the color of the food key and the schedule of shock that was correlated with the food key color.

Control of concurrent avoidance and appetitive behaviors by an indicator of shock proximity.

Two monkeys were exposed to concurrent schedules in which every fifth response on one lever had the dual consequences of delivering food and stepping a 20-step light counter upward; responses on a second lever stepped the light downward. By responding appropriately on each lever, a ration of food could be obtained without exposure to a brief shock that occurred when the counter reached the twentieth step. Behavioral patterns of light-counter control were analyzed when the monkeys were handicapped by several types of discontinuities in the 20-step counter: (1) different sets of four consecutive lights inoperative, (2) the upper or lower 10 steps inoperative, and (3) all lights inoperative.

Fractional punishment of fixed-ratio performance.

Key-peck responses of pigeons under a fixed-rate 60 (Exp. I) or fixed-ratio 99 (Exp. II) schedule of positive reinforcement were punished by response-dependent electric shock during a segment of the ratio.

Reversal of preference under progressive-ratio schedules by punishment.

A progressive-ratio reinforcement schedule, in which successive reinforcements required an additional 50 responses, was programmed on one key. A response on a second key reset the progressive-ratio schedule to the first step. Before punishment, all pigeons consistently reset the schedule after reinforcement on the first step, thereby minimizing the number of responses required for reinforcement.

MODIFICATION OF OBSERVING BEHAVIOR.

The effects on monitoring performance of a limited hold (LH) terminated by a bell or by electric shock and of periodic rest periods were investigated. The sensitivity of basal skin conductance to different monitoring conditions was also studied. Humans monitored a visual display in several 2-hr sessions under the Holland procedure.

SELECTIVE PUNISHMENT OF FIXED-RATIO PERFORMANCE.

Key-pecking of pigeons, maintained by an FR 50 grain reinforcement schedule, was punished by shocking the first, middle, or last response of the ratio. Under high shock levels, the three punishment conditions produced differential effects on the behavior. Punishment of the first response of the ratio resulted in consistent and extended post-reinforcement pausing and frequent extended breaks after the initial response(s) of the ratio.

SELECTIVE PUNISHMENT OF CONCURRENT PROGRESSIVE RATIO BEHAVIOR.

Key pecking of pigeons was reinforced with grain on a progressive ratio schedule during the presence of either of two key colors. Under one color, all responses were shocked; under the other color, responses were not shocked. A single response on a second key switched the key color and reset the progressive ratio, provided that the first step of the progressive ratio had been completed.

AN AVERSIVE STIMULUS AS A CORRELATED BLOCK COUNTER IN FR PERFORMANCE.

After the performances of two pigeons had stabilized on an FR 100 grain reinforcement schedule, response-contingent shock was introduced in the form of a block counter. When shock intensity increased in successive thirds of the ratio, duration of post-reinforcement pauses increased and local rate in an advanced part of the ratio declined. With decrements of shock intensity in successive thirds of the ratio, running rate was not consistently affected but pauses after reinforcements were longer than those under the increasing counter.