Adaptive testing by computer.
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Computers↗
Biomedical subjects
D J Weiss
Publications and source records attributed to D J Weiss.
Idiopathic aplastic anemia in a dog.
A case of idiopathic aplastic anemia in a dog was characterized by pancytopenia and bone marrow aplasia. Erythroid colony-forming units (CFU-E) were not detected in bone marrow culture. Addition of the dog's serum to CFU-E culture from control dogs failed to suppress colony formation, suggesting that humorally-mediated suppression at the CFU-E level was not a cause of the aplastic anemia.
Journal Article↗
Screening coagulation tests in the cat: reference values based on direct venipuncture and catheterized samples.
Platelet count, prothrombin time, activated partial thromboplastin time, fibrinogen degradation products, fibrinogen, and modified thrombin time were determined in 46 healthy adult cats. Samples were obtained by direct venipuncture (pet cats, n=20) or through an 18 gauge intravenous jugular catheter (laboratory conditioned cats, n=26). Range, mean, standard error, and 95% confidence interval were tabulated for the 2 samples. A statistically significant difference between the two groups of cats (Student's t test, p <.05) was found for fibrinogen. No statistical difference was detected between the two groups of cats for the other laboratory values.
Journal Article↗
Bone marrow necrosis associated with pancytopenia in a cow.
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Animals↗
Uniform evaluation and semiquantitative reporting of hematologic data in veterinary laboratories.
A protocol was presented for uniform evaluation and reporting of hematologic data in veterinary clinical laboratories. The protocol was used in the Clinical Pathology Laboratory at Michigan State University for 2 years and was found to improve the recognition and quantification of morphologic changes in blood smears.
Journal Article↗
Studies of the pathogenesis of anemia of inflammation: erythrocyte survival.
Erythrocyte survival was investigated in healthy cats and in cats with sterile abscesses. Erythrocyte survival time in cats with sterile abscesses was found to be significantly reduced. The erythrocyte destruction appeared to be the major factor in the early stages of anemia of inflammation.
Anemia↗
Studies of the pathogenesis of anemia of inflammation: mechanism of impaired erythropoiesis.
Cats with induced sterile abscesses developed a hematologic disorder consistent with anemia of inflammation. Serum iron concentrations decreased while the abscess was present, but erythropoietin concentrations did not change significantly. Cobalt administration to control (healthy) cats resulted in polycythemia, reticulocytosis, and hyperferremia. Cats with abscesses responded to cobalt similarly; however, magnitudes of the polycythemia and reticulocytosis were less. Constant infusion of ferric citrate (IV) into cats with sterile abscesses maintained serum iron concentration in the normal to high range. The iron infusion did not prevent the anemia, but did enable the bone marrow to respond to the anemia.
Anemia↗
The impossible dream of Fechner and Stevens.
The idea that there is a single psychophysical function which describes how the human responds to stimulus intensity is rejected. The form of any empirical function depends upon the buried yet arbitrary assumption about how the stimuli are to be measured. Because psychophysical functions have this arbitrary basis, there can be no universal law, and further, no psychophysical function can reveal a general truth about the nervous system. The power law has been inappropriately reified; the descriptive usefulness of the power function has been incorrectly extended, perhaps because simplicity is appealing.
Differential Threshold↗
Subjective hypotenuse estimation: a test of the Pythagorean theorem.
The Pythagorean theorem constitutes a normative model for the estimation of the length of the hypotenuse of a right-angled figure. Tested with functional measurement methods, this mathematically correct model was inappropriate as a descriptive model. The problem was an orientation effect; hypotenuse estimates for vertically oriented figures were larger than those for horizontally oriented figures composed of the same lengths. Because of this discrepancy, no additive model could describe the judgments.
Adolescent↗
Test of a multiplying model for estimated area of rectangles.
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Form Perception↗
Need type and job satisfaction among industrial scientists.
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Adult↗
Pasteurella haemolytica A1 and bovine respiratory disease: pathogenesis.
The severe fibrinonecrotic pneumonia associated with pneumonic pasteurellosis usually results from colonization of the lower respiratory tract by Pasteurella haemolytica biotype A, serotype 1(A1). Despite recent research efforts, the authors lack a detailed understanding of the interactions and host response to P. haemolytica in the respiratory tract. The authors hypothesize that management and environmental stress factors or viral infection alters the upper respiratory tract (URT) epithelium allowing P. haemolytica to colonize the epithelium. Once the URT is colonized, large numbers of organisms enter the lung where they interact with alveolar macrophages. Endotoxin, released from the bacteria, crosses the alveolar wall where it activates pulmonary intravascular macrophages, endothelium, neutrophils, lymphocytes, platelets, complement, and Hageman factor leading to complex interactions of cells and mediators. It is the progression of this inflammatory response with neutrophil influx that is ultimately responsible for the pulmonary injury. Leukotoxin is a major virulence factor of P. haemolytica that allows it to survive by destroying phagocytic cells. At subcytolytic concentrations it may also enhance the inflammatory response by activating cells to produce mediators and release reactive oxygen metabolites and proteases.
Animals↗
Hypophosphatemia and hemolytic anemia associated with diabetes mellitus and hepatic lipidosis in cats.
Hypophosphatemia associated with hemolytic anemia was diagnosed in five cats with diabetes mellitus and in one cat with idiopathic hepatic lipidosis. The hematocrit began decreasing within 24 to 48 hours after documented hypophosphatemia in each case. The anemia resolved in all five surviving cats. Because of the temporal relationship and lack of other detectable causes, hemolytic anemia was presumed to be caused by hypophosphatemia. There were increased Heinz bodies in three of six hypophosphatemic cats during episodes of hemolysis. Intravenous potassium phosphate administration corrected the hypophosphatemia in four of five cats. The effective dosages of intravenous phosphate ranged from 0.011 to 0.017 mmol of phosphate/kg/h for 6 to 12 hours. Hypocalcemia (5.4 to 8.7 mg/dL) occurred in four of five cats treated with intravenous phosphate; however, only one cat developed clinical signs attributable to hypocalcemia. Based on this retrospective study, we recommend monitoring serum phosphorus concentration every 6 to 12 hours in cats likely to become hypophosphatemic. Treatment of hypophosphatemia in cats is warranted because of the apparent increased susceptibility of cats to hypophosphatemia-induced hemolysis. Cats with severe hypophosphatemia (< or = 1.5 mg/dL) should be given oral or parenteral phosphate if contraindications do not exist.
Anemia, Hemolytic↗
Detection of antiplatelet antibody with a platelet immunofluorescence assay.
An indirect platelet immunofluorescence assay (PIFA) was developed for detection of circulating antiplatelet antibody in dogs with suspected immune-mediated thrombocytopenia (ITP). The PIFA was performed on 10 healthy dogs with normal platelet counts; 76 thrombocytopenic dogs, 20 of which were suspected of having ITP; and 18 dogs with other diseases and normal platelet counts. All normal dogs and negative test results. Fourteen (70%) of 20 dogs suspected of having ITP had positive test results. Fifteen of the remaining 56 thrombocytopenic dogs had positive test results, 9 had cancer and 6 had other immune-mediated diseases including systemic lupus erythematosus (SLE). In this study, the PIFA assay seemed to be more sensitive (70%) than the megakaryocyte immunofluorescence assay (41%) in the diagnosis of ITP. Of the 9 PIFA-positive dogs with neoplasia, 6 had lymphoproliferative disorders. The PIFA was positive in 5 of 18 diseased dogs with normal platelet counts. There was an inverse relationship between the platelet count and the intensity of fluorescence in the PIFA-positive dogs. We conclude that the PIFA is a sensitive screening method for detecting circulating antiplatelet antibody.
Animals↗
Platelet dysfunction associated with immune-mediated thrombocytopenia in dogs.
The effect of antiplatelet antibody on in vitro platelet function was investigated in 15 dogs with immune-mediated thrombocytopenia (ITP). Platelet aggregation was assessed after addition of serum from healthy dogs (n = 5) or dogs with ITP (n = 15) to platelet-rich plasma from a healthy donor dog. The aggregation responses to adenosine diphosphate, thrombin, and collagen/epinephrine were measured as the maximum aggregation observed after 2 minutes. In 13 of 15 dogs with ITP, maximal aggregation was significantly inhibited in response to ADP, thrombin, or collagen/epinephrine. The slope of the aggregation curve was decreased after addition of serum from 9 of 15 patients. A polyclonal rabbit anti-dog platelet antiserum induced inhibition of aggregation with all 3 agonists. Serum from control dogs neither inhibited nor activated platelet aggregation. Aggregation experiments were repeated with all 3 agonists after addition of patient immunoglobulin (Ig)G or IgG from a healthy dog to platelet-rich plasma. The IgG fraction from 9 of 10 dogs with ITP suppressed platelet aggregation. The IgG fraction from polyclonal rabbit anti-dog platelet antiserum inhibited platelet aggregation with all agonists. These results suggest that many canine ITP patients have circulating antibodies that, in addition to causing platelet destruction, may cause platelet dysfunction.
Adenosine Diphosphate↗
Anti-liver membrane protein antibodies in dogs with chronic hepatitis.
Serum from 21 dogs with chronic hepatitis was evaluated for anti-liver membrane protein (anti-LMP) antibodies by an enzyme-linked immunosorbent assay. Ten of the 21 dogs had anti-LMP antibody concentrations greater than 2 SD above the mean value for the 10 healthy control dogs; titers ranged from 1:40 to greater than 1:1,600. Anti-LMP-positive dogs were not restricted by breed, had higher alanine amino transferase activity and total bilirubin concentration, and more severe liver lesions when compared with anti-LMP-negative dogs. This study provided evidence of humoral autoantibodies in dogs with chronic hepatitis, but it did not determine if the autoantibodies were primary or secondary.
Alanine Transaminase↗
The sepsis-coagulant axis: a review.
Activation of coagulation is a normal component of the acute inflammatory response. Inflammatory cytokines initiate coagulation events locally at sites of inflammation by converting endothelium from an antithrombotic surface to a prothrombotic surface; by stimulating tissue factor production, which activates both the extrinsic and intrinsic coagulation systems; and by stimulating production of platelet-activating factors. The fibrinolytic system is initially activated but is subsequently inhibited. This results in a marked imbalance in coagulation and fibrinolysis resulting in a net procoagulant state. When thrombin generation and platelet activation exceed the body's capacity to inactivate or remove these factors, disseminated intravascular coagulation (DIC) results. DIC directly contributes to multiple organ failure and death associated with sepsis. Presently available treatments (i.e., heparin and aspirin) are relatively ineffective in treating DIC; however, newer, more potent drugs may soon be available for clinical use.
Animals↗
Platelet kinetics in dogs treated with a glycoprotein IIb/IIIa peptide antagonist.
Platelet glycoprotein IIb/IIIa (GPIIb/IIIa) receptor antagonists have been highly effective inhibitors of platelet aggregation in preclinical studies and in clinical trials. However, decreased platelet counts have been documented in preclinical studies and in some patients receiving GPIIb/IIIa antagonists. We evaluated changes in platelet kinetics and fate in dogs receiving the GPIIb/IIIa receptor antagonist RPR 109891 orally for 4 days. Dogs receiving RPR 109891 had a 22-52% decrease in platelet count with the nadirs at 3-5 days after initiation of treatment. Platelet survival time was reduced by 19%, and platelet half-life was reduced by 63%. Indium-111-labeled platelets were rapidly cleared from the blood within 1 hour after administration of RPR 109891 on treatment days 1 and 2. This clearing was associated with a sharp increase in radioactivity in spleen but not in liver or lung. Platelet clearance was markedly attenuated on treatment days 3 and 4. Platelet counts returned to baseline within 1 week after discontinuation of treatment. These data indicate that RPR 109891 causes rapid and selective sequestration of platelets in the spleen.
Administration, Oral↗