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Biomedical subjects

R A Green

Publications and source records attributed to R A Green.

At least 19 recordsLinked to original sources
PubMed1992

Effects of single-dose L-asparaginase on coagulation values in healthy dogs and dogs with lymphoma.

Ten healthy dogs and 10 dogs with multicentric lymphoma were given a single dose of L-asparaginase at a rate of 10,000 IU/m2 of body surface. Assessment of concentrations of contributors to the coagulation process and of the ability to coagulate including antithrombin III, one-stage prothrombin time, prothrombin-proconvertin time, activated partial thromboplastin time, plasminogen, fibrinogen, and platelet number were performed prior to drug administration (day 0). These tests were repeated 24 hours (day 1), 48 hours (day 2), and 7 days after treatment with L-asparaginase. Antithrombin-III concentrations were significantly lower in the dogs with lymphoma than in healthy dogs on days 0, 1, 2, and 7; however, with the exception of day 1, mean values remained within normal limits. There was also a difference between the 2 groups in prothrombin/proconvertin values on day 7 and in platelet number on day 2, with the lymphoma group having significantly shorter prothrombin/proconvertin time than healthy dogs, and the difference in platelet numbers being associated with increased counts in the healthy dogs. Data obtained from the healthy dogs and dogs with lymphoma for each coagulation test were pooled for each treatment day (0, 1, 2, and 7), and day-0 values for each coagulation test were compared with data obtained on days 1, 2, and 7. Antithrombin-III concentration on day 7 was significantly lower than on day 0, prothrombin/proconvertin time on day 1 was significantly longer than on day 0, and fibrinogen concentrations on days 1 and 2 were significantly lower than on day 0.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Indocyanine green disposition in healthy dogs and dogs with mild, moderate, or severe dimethylnitrosamine-induced hepatic disease.

Disposition kinetics of indocyanine green (ICG) were used to evaluate hepatic function in healthy Beagles (group 1; n = 6) and Beagles with progressive hepatic disease induced by oral administration of dimethylnitrosamine, a hepatospecific toxin. Three classes of hepatic disease were defined by histologic features: mild (group 2; n = 5), moderate (group 3; n = 6), and severe (group 4; n = 5). Disposition of ICG was studied 3 weeks following the last dose of toxin. A rapid IV injection of 0.5 mg of ICG/kg was administered and serum samples were obtained at certain intervals during 60-minute periods. Serum ICG was analyzed by use of visible spectrophotometry. Disposition kinetics were determined from serum ICG concentrations vs 15- and 60-minute time curves and compared between one another and among groups. Data based on 60-minute time curves were not significantly different from those based on 15-minute curves. Area under the curve for ICG was greatest in group 3. Clearance of ICG was decreased and mean resident time was increased in groups 3 and 4, compared with those in groups 1 and 2. When disposition data (60 minutes) were normalized for differences in hepatic weight among dogs, group-3 mean resident time was significantly greater than that of group 4. This study supports the diagnostic benefits of using ICG disposition kinetics as a method of evaluating hepatic function in dogs with progressive liver disease.

Animals↗
PubMed1992

Dimethylnitrosamine-induced hepatotoxicosis in dogs as a model of progressive canine hepatic disease.

A model of toxin-induced progressive hepatitis is described in Beagles. The toxin, dimethylnitrosamine, was administered orally to 18 Beagles; 6 dogs comprised a control group. Clinical signs and laboratory test results were monitored as disease progressed and were used to determine the end point of disease. Following euthanasia, histologic lesions were scored and used to derive a total severity score for each dog. Severity scores were then used to allot the 18 dogs to 3 groups of hepatic disease, defined as mild, moderate, or severe. Changes in clinical laboratory test results, including tests of hepatic function, and clinical signs indicative of liver disease were described chronologically for all dogs. Group means of clinical laboratory test results and quantifiable clinical signs (eg, weight loss and ascitic fluid accumulation) were compared. This model offers several advantages, compared with other experimental models of canine hepatic disease. These include hepatospecificity, similarity to natural disease (eg, the development of multiple extrahepatic portosystemic shunts), and the ability to titrate the disease to a desired end point. The major disadvantages of this model were the toxic nature of the drug to human beings and the variation in individual animal response to the toxin, which precludes preassignment of animals into groups.

Animals↗
PubMed1990

The correlation of subcarinal density visualized on plain chest roentgenograms with computed tomographic scans.

A prospective evaluation of 212 paired chest roentgenograms and computed tomographic (CT) scans was performed to determine the predictive value of detecting subcarinal adenopathy by finding increased subcarinal density on routine roentgenograms. Based on CT criteria for subcarinal lymphadenopathy, 37 true-positive and 124 true-negative cases of subcarinal adenopathy were found in 161 patients. Evaluation of density in the subcarinal area on the routine posteroanterior (PA) chest roentgenograms in these patients demonstrated a sensitivity of 72 percent and specificity of 96 percent for the detection of adenopathy when compared with established CT criteria. False-positive and false-negative appraisals of central mediastinal density on routine roentgenograms appear to be due to the super-imposition of other masses, bullae, or lack of appropriate roentgenographic contrast. The accuracy of predicting the presence or absence of subcarinal adenopathy from routine chest roentgenograms suggests that this observation is clinically useful and should be routinely evaluated.

False Negative Reactions↗
PubMed1978

Perspectives of clinical osmometry.

Several clinical applications of osmometry have been reviewed. Questions remain concerning the clinical acceptance that osmometry will achieve in veterinary medicine. Many practices may not be able to justify the purchase of an osmometer; however, osmometers are available at most medical centers and clinical laboratories. In an era when serum chemistry profiles are being used more frequently, it may prove that serum osmolatity will be requested more frequently. Determination of osmolality is a simple, rapid, and inexpensive test that has potential in screening for disorders of body fluids. Several research laboratories utilize osmometry routinely in screening for potential fluid or electrolyte inbalances. When coupled with glucose, blood urea nitrogen, and electrolyte values, a comparison of calculated and measured osmolality allows further clinical interpretations. Differences may exist between calculated and measured osmolality. In some instances, determination of calculated osmolality alone may lead to erroneous conclusions concerning the true status of body fluids. Specialized intensive care practices should certainly consider the value of osmometry in monitoring patients undergoing extensive fluid therapy. Last, but not least, osmometry does provide the best measure of renal concentrating ability and is of particular value in evaluation of polyuric and proteinuric patients.

Animals↗
PubMed1978

Changes in obstetric anaesthesia in the last twenty-five years.

The last twenty-five years have provided a continuing success story in the achievement of satisfactory obstetric analgesia. Maternal mortality and morbidity from general anaesthesia has not decreased substantially. Mothers still run the same risk of inhalational pneumonitis and are even more likely to suffer the distressing experience of awareness. It must, however, be admitted that general anaesthesia for child-birth has brought increasing benefits to the new born during the last twenty-five years.

Anesthesia, Epidural↗
PubMed1978

Experimental lead intoxication in dogs: a comparison of blood lead and urinary delta-aminolevulinic acid following intoxication and chelation therapy.

Intravenous lead administration to dogs produced an acute syndrome of lead intoxication charcterized by depression, vomiting, anorexia and weight loss. The effect of chelation therapy with calcium disodium ethylene diamine tetraacetate, penicillamine or both was determined by serially monitoring changes in blood lead and urine delta-aminolevulinic acid. Following therapy, blood lead values were significantly lower in chelated dogs than non-treated lead exposed dogs on days 7 and 10. Urine delta-aminolevulinic acid at day 7 was significantly higher in untreated lead exposed dogs than in other groups. There was no significant difference in blood lead or urine delta-aminolevulinic acid between lead intoxicated dogs which underwent the indicated chelation therapy protocols. There was, however, a trend for higher urinary delta-aminolevulinic acid excretion in those intoxicated dogs undergoing calcium disodium ethylene diamine tetraacetate therapy as opposed to those undergoing penicilamine therapy. There was no significant correlation between blood lead and urinary delta-aminolevulinic acid previous to lead exposure. However, after lead exposure significant correlation was present at days 4, 7, 10 and 14. Certain lead exposed dogs following chelation therapy were noted to have normal blood lead levels but elevated urinary delta-aminolevulinic acid suggesting that blood lead does not always correlate with metabolic effects of lead in the body. Urinary delta-aminolevulinic acid was therefore recommended as an additional laboratory parameter which improved assessment of lead exposure in dogs, particularly in determining adequacy of chelation therapy.

Aminolevulinic Acid↗
PubMed1977

Patterns of exogenous and endogenous hematopoietic repopulation following radiation injury.

Patterns of hematopoietic recovery in mice given an LD50/30 radiation exposure were different from those in animals given an LD100/30 exposure and a marrow transplant sufficient to effect 50 per cent 30-day survival. Death occurred later, and recovery of some peripheral blood elements was delayed in the LD50/30 mice. Over the period of study, splenic hematopoiesis and stem cell renewal were insignificant in the LD50/30 mice yet were active in the marrow-transplanted animals. The slow recovery of erythropoiesis in the LD30/30 mice is explained in part by the lack of early splenic hematopoiesis. This effect appeared to be attributable to the splenic microenvironment which, although being suitable for growth of unirradiated hematopoietic cells, was not conducive to repair of radiated splenic hematopoietic cells.

Animals↗
PubMed1977

Feline factor XII (Hageman) deficiency.

A coagulation profile from a clinically normal female cat revealed an intrinsic coagulation defect characterized by prolonged activated partial thromboplastin time, with normal bleeding time, platelet count, and prothrombin time. Subsequent correction studies, utilizing activated partial thromboplastin time, confirmed factor XII deficiency. Hematologic and clinical studies on the cat failed to reveal an underlying disease process that might result in acquired factor XII deficiency.

Animals↗
PubMed1976

The inhibitory effect of intraventricular administration of serotonin on spontaneous motor activity of rats.

Spontaneous motor activity was studied following injection of 1, 10 and 50 mug of serotonin (5-HT) into the lateral ventricle of chronically cannulated rats. During the first 15 min, the rats receiving the higher doses of 5-HT showed significant decrements (P less than 0.01) in motor activity compared to saline controls. No activation was observed in either group. After 20 min, no significant differences for any treatment condition compared to saline controls were observed. It is concluded that a principal effect of directly increasing brain 5-HT concentration is to decrease activity. Possible mechanisms for this effect are discussed.

Animals↗
PubMed1976

The tryptolines: effect of intraventricular administration on spontaneous motor activity of rats.

The pharmacologic properties of the tryptolines, hindered analogues of the tryptamines, were studied behaviorally in rats. Following intraventricular injections, it was found that spontaneous motor activity decreased markedly during the initial 25 mins when compared with saline. Since both the tryptolines and tryptamines have been shown to be inhibitors of 5-hydroxytryptamine uptake, it may be possible that these compounds are acting indirectly throught an effect on the serotonergic system.

Animals↗