PubMed Health⌕ Search

Biomedical subjects

Harold W. Tvedten

Publications and source records attributed to Harold W. Tvedten.

11 recordsLinked to original sources
PubMed1999

Artifactual effects of hypernatremia and hyponatremia on red cell analytes measured by the Bayer H*1 analyzer.

Hypernatremia in two cats and hyponatremia in a dog were associated with artifactual changes in red blood cell (RBC) indices and hematocrit (HCT) determined on a Bayer H*1 hematology analyzer. The RBC cytograms and histograms revealed a population shifted towards macrocytic, hypochromic RBC in the hypernatremic cats, and towards microcytic, hyperchromic RBC in the hyponatremic dog. Reference intervals for the difference between manual packed cell volume (PCV) and analyzer-derived HCT in normonatremic dogs, cats and horses were established. The difference between PCT and HCT was outside the reference values for all three patients. Quality control measures, such as measuring PCV, and reviewing cytograms and histograms are essential for detecting spurious changes in automated hematology measurements caused by abnormalities in serum sodium concentration and osmolality.

Journal Article↗
PubMed1998

Hematopathology in dogs experimentally infected with a Swedish granulocytic Ehrlichia species.

Seven, adult, female beagles were inoculated with a Swedish granulocytic Ehrlichia organism closely related to Ehrlichia equi and E. phagocytophila. Blood and bone marrow changes were evaluated throughout the acute phase of infection. All dogs developed moderate to severe thrombocytopenia during the parasitemic period. The mean platelet volume and platelet distribution width increased, and large platelets were seen on blood smears when platelet numbers were low. In bone marrow, absolute numbers of megakaryocytes and immature megakaryocytes were increased. These results suggested the thrombocytopenia was caused by increased platelet destruction. The dogs also developed mild, normocytic, normochromic anemia, with simultaneous decreases in serum iron concentration and total iron-binding capacity that resembled the anemia of inflammation. In bone marrow, there was a slight increase in immature erythroid cells and no erythroid hypoplasia; iron stores were normal to increased. Myeloid hyperplasia was seen in all infected dogs, despite neutropenia in peripheral blood. Lymphopenia occurred early in the parasitemic period, but lymphocytes responded strongly and numbers increased above baseline levels by the end of parasitemia. Blast-transformed lymphocytes (5% to 20%) were seen in peripheral blood for a few days. Experimentally-induced canine granulocytic ehrlichiosis caused cytopenias of short duration, coincident with the appearance of ehrlichial inclusions in neutrophils.

Journal Article↗
PubMed1996

Automated differential leukocyte count in horses, cattle, and cats using the Technicon H-1E hematology system.

The differential leukocyte counts performed by an automated hematology analyzer, the Technicon H-1E Hematology System, and traditional microscopic method (M-Diff) from blood samples of 129 horses, 40 cattle, and 140 cats were compared. The comparison was repeated after selected subsets of data were created by deleting samples with certain patterns suggesting error with the automated differential cell count (A-Diff). The two methods had good comparison of results for neutrophils and lymphocytes in all three species. Results for equine monocytes correlated moderately well between the two methods and the correlation improved in the selected data set Monocyte results did not compare well for the bovine and feline samples. The A-Diff for feline eosinophils was inaccurate. The A-Diff may be accurate for bovine and equine eosinophils but too few examples of eosinophilia were present in the sample set to prove this. Basophils were too rarely seen in cattle and horses to validate A-Diff accuracy, but basophilia identified by the M-Diff in a cat was not identified by the A-Diff.

Journal Article↗
PubMed1992

Serum lipase determination in the dog: a comparison of a titrimetric method with an automated kinetic method.

An enzymatic, kinetic method for determining serum lipase activity was evaluated and compared to a standard manual method for use in dogs. The kinetic method was a commercial kit adapted for use on a tandem access clinical chemistry analyzer and utilized a series of coupled enzymatic reactions based on the hydrolysis of 1,2-diglyceride by lipase. The manual method was the Cherry-Crandall technique based on the titration of base against the acid formed by hydrolysis of an olive oil substrate by lipase. The correlation between the two methods was very good (r = 0.94). The reference range for 56 clinically healthy dogs assayed by the kinetic method was 90 to 527 U/L. Diseases associated with a greater than twofold elevation in serum lipase activity as determined by the kinetic method included pancreatitis, gastritis with liver disease, and oliguric renal failure with metabolic acidosis. In some cases, pancreatitis was seen with other clinical problems, such as gastroenteritis, diabetic ketoacidosis, duodenal mass, disseminated intravascular coagulation, and septic peritonitis. Diseases associated with serum lipase activity within the reference range or elevated less than twofold included gastritis, gastric ulcer, cholestasis, phenobarbital-induced hepatopathy, colitis, copper hepatopathy, abdominal hematoma, apocrine gland adenocarcinoma, and thrombocytopenia with pneumonia.

Journal Article↗