Coherent imaging with two-dimensional focal-plane arrays: design and applications.

Scanned, single-channel optical heterodyne detection has been used in a variety of lidar applications from ranging and velocity measurements to differential absorption spectroscopy. We describe the design of a coherent camera system that is based on a two-dimensional staring array of heterodyne receivers for coherent imaging applications. Experimental results with a single HgCdTe detector translated in the image plane to form a synthetic two-dimensional array demonstrate the ability to obtain passive heterodyne images of chemical vapor plumes that are invisible to normal video infrared cameras. We describe active heterodyne imaging experiments with use of focal-plane arrays that yield hard-body Doppler lidar images and also demonstrate spatial averaging to reduce speckle effects in static coherent images.

Pharmacokinetics and anesthetic potency of a thiopental isomer.

In developing a high-performance liquid chromatographic assay for thiopental [5-ethyl-5-(1-methylbutyl)-2-thiobarbituric acid], a thiopental isomer [5-ethyl-5-(1-ethylpropyl)-2-thiobarbituric acid] was found. This isomer occurs (6-7%) in supposedly pure thiopental and in the commercially available thiopental sodium administered to patients for induction of anesthesia. A similar type of isomer also occurs in pentobarbital, the oxybarbiturate analogue of thiopental. Because the disposition and anesthetic potency of the isomer is unknown, its pharmacokinetic properties were determined in humans and its anesthetic potency in mice. In five surgical patients, the terminal elimination half-life, clearance, and volume of distribution at steady state of the isomer were not statistically different from those of thiopental. In mice, the isomer proved to be as effective as thiopental for induction of anesthesia. The LD50 and sleep time at one-half the LD50 did not statistically differ between the two compounds in mice. The close structural similarity of thiopental and the isomer results in similar pharmacokinetic and anesthetic properties. It does not appear critical that the isomer be separated from thiopental in subsequent pharmacological research.

Electrophysiologic studies of a combination of secobarbital and dibucaine for euthanasia of dogs.

A combination of secobarbital and dibucaine was compared with secobarbital and with dibucaine, given IV, for euthanasia of dogs. The secobarbital-dibucaine combination was the most effective, as determined by latency to electrical silence of the EEG and ECG, as well as by visual observation of the behavior of the animal. The combination product produced a quiet and rapid death, according to all electrophysiologic changes that were monitored, whereas the barbiturate resulted in prolonged myocardial activity. Dibucaine alone is not desirable for use for euthanasia.

Why physicians attend traditional CME programs.

The reasons physicians attend traditional continuing medical education (CME) programs have not been studied extensively. Based on a review of the literature, reasons for participation are categorized as an integral part of professionalism, an interest in topical subjects, a means of validating or modifying prior learning and behavior; a means of attaining an identified learning or behavioral objective, and a change of pace from practice routine and an opportunity for social contact with other physicians. Individual physicians may attend a particular CME program for reasons that include several of these categories. Physicians' inner standards of achievement and need to validate their information and practices are seen as more important reasons for CME attendance than are mandatory CME regulations and change of pace.

Structure-activity relationships in the effects of phenacemide analogs on serum creatinine and anticonvulsant activity.

The anticonvulsant phenacemide had been shown to produce a marked rise of serum creatinine in humans and experimental animals without significant impairment of renal function. The mechanisms is not yet fully elucidated. A series of aromatic and aliphatic analogs of phenacemide were tested in rabbits under standardized conditions. A number of chemicals-structural requirements for this effect could be recognized within the limited number of compounds available. None of them exceeded the potency of phenacemide. There was no consistent correlation between the effect of serum creatinine and anticonvulsant potency in mice.

Broadband stable detector for ultraviolet (300-1700 A) plasma spectroscopy.

A CuI coating on the first dynode of a windowless photomultipler creates a broadband and stable detector for ultraviolet plasma spectroscopy with a quantum efficiency above 2% from 400 to 1600 A. The stability of this photocathode was tested in the environment of tokamak discharges; no degradation was found after one year's use.

Rise in serum and urine creatinine after phenacemide.

Three patients under treatment with phenacemide for uncontrollable psychomotor epilepsy were found to have greatly increased serum creatinine levels in the absence of elevated blood urea nitrogen (BUN) values or any other evidence of renal disease. Serum creatinine returned promptly to normal after omission of the phenacemide and rose quickly again on resumption. Experiments in rabbits and rats fully reproduced these clinical observations. In vivo and in vitro studies with the drug and its metabolites excluded these as a cause for a spurious analytical finding. Rabbits given phenacemide have a fall in serum and urine creatine, while the corresponding creatine values rise. With the use of a creatininase degradation procedure, it could be proved that the markedly elevated serum level and the increased excretion consist of the creatinine and not of any other substance. An effect of phenacemide on the conversion rate of creatinine to creatinine in the body is a speculative possibility.

A study of the effect of d-amphetamine on the toxicity, analgesic potency and swimming impairment caused by potent analgesics in mice.

The addition of d-amphetamine to morphine has been reported to result in an increase of analgesic potency in experimental animals and man, but no data on the toxicity of such combinations are available. This study is intended to provide systematic information on the toxicity, analgesic potency and degree of physical impairment (swimming endurance) of a combination of 12 mg morphine sulfate with 10 mg d-amphetamine HCl per ml which is now under clinical investigation. Mice were used as experimental subjects. Meperidine, methadone and pentazocine were substituted for morphine using clinically equally analgesic doses and keeping the d-amphetamine amount constant. The toxicity of all analgesics especially that of morphine was enhanced in the combination, least so in the case of meperidine. The degree of increase of analgesic power by the addition of d-amphetamine was greatest with morphine and quantitatively in satisfactory agreement with present clinical experiences. However, the relationship between the increases of toxicity and of analgesia is not necessarily most favorable for this drug. For the other three analgesics increases in toxicity and analgesia were more in line, meperidine showing the best ratio. Swimming endurance was decreased with full analgesic doses of all four compounds. The presence of d-amphetamine tended to reverse this depression. The data were analyzed in relation to their possible predictive value for the use of such combinations in man for the therapeutic dose range and in the event of overdosage.