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Biomedical subjects

T Adams

Publications and source records attributed to T Adams.

At least 109 records · Page 6Linked to original sources
PubMed1990

Cholinergic reactivity of tracheal smooth muscle after infection with feline herpesvirus I.

Airway responsiveness was studied in cats 3 or 6 days after exposure to feline herpesvirus I. Control cats were sham inoculated with tissue culture media. Intrathoracic airway caliber was evaluated by pulmonary resistance (RL) and dynamic compliance (Cdyn). Trachealis shortening was quantitated with microfoil strain gauges, which measured the external diameter of tracheal ring 4. Airway smooth muscle contraction was produced using vagal stimulation and local infusion of acetylcholine. The diameter of tracheal ring 4 decreased with increasing frequency of vagal stimulation, and there was more constriction at 3 (PID3) than at 6 days postinfection (PID6) or in control cats. RL increased and Cdyn tended to decrease with increasing frequency of stimulation, but there was no difference between control and infected cats. Infected and control cats did not differ in their response to locally infused acetylcholine. Virus was consistently cultured from conjunctival, nasal, and oral mucous membranes, trachea, and main stem bronchi at PID3 but not from the trachea and main stem bronchi at PID6. Virus was never isolated distal to the main stem bronchi. Tracheal hyperresponsiveness to vagal stimulation correlates with the presence of virus at PID3 and is apparently presynaptic in origin.

Acetylcholine↗
PubMed1990

Clinical study of keratoconus in central Kentucky.

Keratoconus is an ectatic corneal disorder that results in a central or inferior conelike anterior protrusion. This results in irregular myopic astigmatism, causing considerable visual impairment. We have completed a retrospective clinical study of keratoconus in the central Kentucky area. When compared to other national studies of keratoconus, our study patients generally had more severe disease at the time of diagnosis and had a higher rate of keratoplasty. Keratoconus treatment is highly successful, and early diagnosis is warranted to prevent unnecessary visual loss.

Adolescent↗
PubMed1988

A supporting role.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1988

The effects of social context and verbal skill on the stereotypic and task-involved behaviour of autistic children.

Twelve autistic children's rates of Stereotypy, Task Involvement and Non Involvement were observed in three settings representing levels of interpersonal contact: Individual Attention, Group Attention and Play. The children were assigned in two groups reflecting high and low verbal skills and overall level of autistic disturbance was used as a covariate. Results showed that the highest levels of Task Involvement and the lowest levels of Stereotypy and Non Involvement were associated with the highest level of interpersonal contact. Verbal skill level predicted higher rates of prosocial behaviour overall, and interacted with the setting measures for Stereotypic behaviours, indicating that the low verbal children tended to self-stimulate most when no demands were made on their behaviour. Implications for further research and educational practice are briefly discussed.

Attention↗
PubMed1988

Physiological, morphological, and histochemical properties of cat external anal sphincter.

The contractile properties, morphology, and the distribution of striated muscle fiber types of the external and sphincter (EAS) were determined using axial force measurements, fiber size cross-sectional area measurements, and histochemistry. Electrical stimulation of motor axons in pudendal nerve at supramaximal intensities (10 V, 0.05 ms duration) elicited twitch contractions of EAS. The time to peak force after a single pulse ranged from 37 to 42 ms. The time for relaxation to half-maximal twitch force ranged from 20 to 29 ms. Repetitive stimulation of motor axons (0.1-3.0 Hz) produced potentiation and fatigue of single twitch contractile force, suggesting that the EAS of the cat is comprised predominantly of fast-twitch muscle fibers. Confirmation of skeletal muscle fiber types was determined by histochemistry. Frozen serial cross sections of EAS were incubated to demonstrate succinic dehydrogenase (SDH) and myosin adenosine triphosphatase after alkaline preincubation (pH 10.4). Based on these reactions, muscle fibers were classified as fast glycolytic (FG) (high ATPase, low SDH), fast oxidative-glycolytic (FOG) (high ATPase, high SDH), and slow oxidative (SO) (low ATPase, high SDH). The mean percentage +/- SE of each histochemical type was the following: FG, 73.5 +/- 3.9; FOG, 22.8 +/- 3.7; and SO, 3.7 +/- 0.6. These results indicate that the predominant fiber type for the EAS is FG. The EAS of the cat is considered a nominally fast-twitch muscle.

Anal Canal↗
PubMed1986

Effect of a proteolytic enzyme inhibitor on the cardiopulmonary response to endotoxin.

Gabexate mesilate (GM), a proteolytic enzyme inhibitor, was given to 31 chronically instrumented sheep either as a pretreatment or treatment to determine its effects on the cardiopulmonary response to endotoxin (ET). Twelve sheep received GM prior to endotoxin (0.75 microgram/kg), 10 after ET and 9 received GM without ET. A typical biphasic response was noted; phase I showed increased lymph flow (QL), reduced lymph to plasma protein ratio (L/P) and increased pulmonary artery pressure (PAP). Phase II occurred two hours after ET; the lymph flow remained elevated and the L/P ratio rose slightly above control. Both phases demonstrated an elevation in total peripheral vascular resistance (TPR) and hematocrit but a reduction in cardiac output (CO). In phase II, QL was reduced 35% with pretreatment; the L/P ratio did not rise as much and the PAP was unchanged. There was also a 35% reduction in lymph flow; no change in the lymph to plasma protein ratio but there was an elevation in pulmonary microvascular pressure. Pretreatment with GM diminished the fall in CO and the rise in TPR seen with endotoxin. The values were unaffected by treatment alone.

Animals↗
PubMed1986

Dinitrotoluene isomer-specific enhancement of the expression of diethylnitrosamine-initiated hepatocyte foci.

Technical grade dinitrotoluene (TDNT) was shown to be a potent hepatocarcinogen in rats; however, ambiguous results were obtained from bioassays which evaluated 2,4-DNT, the principal isomer in the technical mixture. The present studies were designed to determine the relative hepatocyte foci promoting activity of TDNT and the primary isomers present in the technical mixture, 2,4- and 2,6-DNT. A rat hepatic initiation-promotion protocol was used in which male Fischer-344 rats were initiated with a single dose of diethylnitrosamine (DEN) (150 mg/kg, i.p.) and permitted to recover for 2 weeks. Following the recovery period, the animals were fed diets containing TDNT,2,4-DNT,2,6-DNT or phenobarbital (PB). The TDNT animals were killed after 3 or 6 weeks of feeding and the 2,4-DNT-,2,6-DNT-and PB-treated animals were killed after 6 or 12 weeks of feeding. Appropriate DEN and DNT controls were also killed at each time point. Sections from three liver lobes of each animal were stained for gamma-glutamyl transferase (GGT) and the number of GGT+ foci per cm3 (Nv) was calculated using stereological methods. TDNT feeding produced a dose-dependent increase in GGT+ foci (Nv) at 3 and 6 weeks relative to both DEN and TDNT controls. Administration of 2,4-DNT and PB produced time-dependent increases in GGT+ foci (Nv), while 2,6-DNT produced dose- and time-dependent increases. Unlike 2,4-DNT and PB, the high dose (14 mg/kg) of 2,6-dNT produced an increase in GGT+ foci in the control groups and in mean foci volume relative to the DEN control. These results establish that TDNT, 2,4-DNT and 2,6-DNT have hepatocyte foci promoting activity and that 2,6-DNT is approximately 10 times more potent than 2,4-DNT. In addition, TDNT administration neither alters hepatocyte replication following partial hepatectomy nor acts as a 'growth selection' agent in the Solt-Farber 'growth selection' model suggesting that differential effects on hepatocyte replication are not responsible for the promoting activity of TDNT. Based on previous initiation study results from our laboratory and the present data, 2,6-DNT appears to be a complete hepatocarcinogen while under the conditions of these studies 2,4-DNT is an apparent 'pure promoter'. These results provide an explanation for the conflicting DNT bioassay results.

Animals↗
PubMed1986

Quantification of axial forces in rectum-anal canal of the cat.

A newly developed probe was used to measure in vivo axial forces in the rectum-anal canal of the anesthetized cat. Spontaneous contractions of the smooth muscle of the internal anal sphincter were recorded, as were neurally evoked contractions of striated muscle of the external anal sphincter. Bilateral electrical stimulation (1-10 V, 1-5 Hz, 0.05 ms duration) of motor axons in pudendal nerves elicited two responses. One was synchronous phasic contractions of skeletal muscle fibers of the external anal sphincter that were not abolished by atropine but were by gallamine trithiodide. They occurred at short latencies (1-2 ms) and were mediated through low-threshold (1-3 V, 0.05 ms duration) efferent axons in the pudendal nerves. Contraction times ranged from 45 to 60 ms, and contraction duration ranged from 100 to 160 ms. The second response was a progressive elevation in tone of the anal canal due to contractions either of the smooth muscle of the rectum and/or that of the internal anal sphincter. The elevation in smooth muscle tone concomitant with pudendal nerve stimulation may be due to reflex activation of cholinergic neural pathways, since the response was abolished by atropine.

Anal Canal↗
PubMed1986

Streptokinase treatment of cats with experimentally induced aortic thrombosis.

An investigation was initiated to determine the dosage of streptokinase (given IV) that would consistently produce systemic fibrinolysis, as determined by laboratory evaluation, and to determine the relative safety of this drug in the cat. Results indicated that a loading dose of 90,000 IU of streptokinase (given by continuous infusion over 20 to 30 minutes) and a maintenance dosage (IV) of 45,000 IU of streptokinase/hr predictably produced systemic fibrinolysis in the cat. There were no detectable adverse affects seen on physical examination, necropsy, or histopathologic examination. Using the foregoing dosage regimen, investigation was begun to evaluate the use of streptokinase for treatment of feline thromboembolism. Aortic thrombosis was created experimentally in 15 cats. There was no clearly predictable improvement in nonspecific venous angiograms or thermal circulatory indices for the cats given streptokinase, compared with the values for the control cats. After a total of 180 minutes of treatment, the mean weight of remaining clot removed at necropsy from the aortic trifurcation was 7.3 mg in the streptokinase-treated cats, compared with 13.4 mg in the control cats.

Angiography↗