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Biomedical subjects

C Angel

Publications and source records attributed to C Angel.

At least 73 records · Page 4Linked to original sources
PubMed1983

[Angiography and perfusion pulmonary scintigraphy in pulmonary embolism].

Clinical signs suggestive of pulmonary embolism require diagnostic confirmation from complementary scintigraphic and/or angiographic examinations, therapy being adapted to the results obtained. A comparative study of the value of the two techniques was conducted in 20 patients with suspected pulmonary embolism investigated by a perfusion pulmonary scan and selective pulmonary angiography. Results confirmed the diagnostic superiority of angiography, the high percentage of false positives obtained by perfusion scintigraphy alone indicating the need for associated ventilatory function tests.

Adult↗
PubMed1982

Induced immobility in nervous and normal Pointer dogs.

Pointer dogs learn complex hunting tasks such as vigorous aim-directed activity in tracking specific birds and sudden rigid immobility "on point" at appropriate distance from the prey. In the presence of a human, dogs of the Arkansas Line of Nervous Pointers show markedly reduced activity. In close quarters, where they cannot flee, they usually react to humans by freezing. These responses do not extinguish. The breed demonstrates a strong capacity to inhibit motion. In our nervous dogs, this trait is greatly exaggerated. In the search for an objective and rapidly modifiable target motor sign to correlate with biochemical and pharmacological events, we discovered that 10 of 10 nervous dogs, in contrast to kennel mates of a normal line, developed tonic immobility (TI) which was induced by manual inversion into a sling and stroking. This is the first systematic demonstration of TI in mature dogs. The TI was accompanied by reduced telemetered heart rate (HR) compared to baseline. Release from the inverted position was accompanied by marked HR increase. In the absence of humans, both before and after the inversion, all nervous dogs showed little or no movement about the testing area. This was in contrast to the nine normal line dogs, which were comparable in age and sex. These normal dogs were very active before and after inversion into the sling. Five of the normals remained in the sling but did not show head and neck immobility and were generally relaxed. Their HRs increased slightly while in the inverted position, thereafter returning to baseline. The four normals which righted themselves soon after the inversion showed reduced HR with the resumed activity. We discuss possible mechanisms and review some of the implications for psychiatry and behavioral biology.

Animals↗
PubMed1976

Probenecid-induced accumulation of cyclic nucleotides, 5-hydroxyindoleacetic acid, and homovanillic acid in cisternal spinal fluid of genetically nervous dogs.

These studies have been conducted on 40 dogs, twenty each of a genetically nervous strain and of a normal strain of short-haired pointers. The nervous strain after about age 3 months displays extreme hypervigilance, timidity, human avoidance, and often shows catatonic-like muscle rigidity when in the presence of humans or novel stimuli. Measurements of probenecid-induced accumulation of acid metabolites in cisternal cerebrospinal fluid (CSF) have been carried out. Among the compounds measured at from 1.5 hr to 6.0 hr after probenecid treatment, homovanillic acid (HVA) was similar for the two strains, 5-hydroxy-indoleacetic acid (5-HIAA) was lower, but cyclic adenosine-3',5'-monophosphate (cAMP) and cyclic guanosine-3',5'-monophosphate (cGMP) were higher for the nervous strain when compared with age- and sex-matched behaviorally normal dogs. Probenecid levels in CSF were similar at all points in time from 1.5 to 6.0 hr after its intravenous administration in a dose of 50 mg/kg body weight. These findings coupled with previously observed differences in the two strains suggest that hyperresponsiveness of the central nervous system (CNS) noradrenergic and cholinergic systems and a hyporesponsiveness of the serotoninergic system are related to the genetically expressed aberrant behavior.

Animals↗
PubMedDate not supplied

A multivariate discriminate analysis of behavioral measures in genetically nervous dogs.

For some years we have studied a strain of genetically nervous dogs in the Neuropsychiatric Research Laboratory, Veterans Administration Hospital, North Little Rock, Arkansas. In the manner of Pavlov and Gantt and later Scott and Fuller we have characterized these dogs in such descriptive terms as timid, human aversive, and catatonic-like. Behavioral tests have been administered on nearly all dogs in this longitudinal study, and we are using these data to try to develop statistical procedures to maximize the discriminatory power of the behavioral assay and to more accurately characterize the behavioral deficit. A multivariate discriminate analysis of 13 variables on 91 healthy and 63 nervous dogs assayed at 3 months of age shows: (1) that much of our present behavioral testing procedures is redundant, and (2) that simple "friendliness to humans" in the dog is as effective for discriminating between the two groups as any of the 13 measures, taken either singly or collectively.

Animals↗