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Biomedical subjects

M G Weiser

Publications and source records attributed to M G Weiser.

34 records · Page 2Linked to original sources
PubMed1987

Size referenced electronic leukocyte counting threshold and lysed leukocyte size distribution of common domestic animal species.

Using a single channel electronic cell counter and attached particle size analyzer, leukocyte size distribution histograms were determined on canine, feline, bovine, and equine blood diluted with chloride-based diluent and treated with a conventional stromatolysin. Histograms were usually unimodal, but a few were bimodal. Mean values for mean lysed leukocyte particle volume were 49.2, 51.1, 55.4, and 65.0 fl for canine, feline, equine, and bovine blood, respectively. From inspection of histograms, a lower threshold of 30 fl referenced to latex spheres was interpreted to be appropriate for counting leukocytes of these four species simultaneously. Debris below the threshold was seen in many samples and was usually separated from the leukocyte population by a valley touching the histogram baseline at the threshold channel. Debris resulted in a visually detectable threshold failure by extending considerably into the leukocyte size range in 9% of feline, 9% of canine, and 7% of bovine samples. It is recommended that careful establishment of the lower counting threshold will minimize frequency and severity of leukocyte count error associated with failure to exclude debris.

Animals↗
PubMed1986

Feline leukemia virus-induced thrombocytopenia and macrothrombocytosis in cats.

The Kawakami-Theilen strain of feline leukemia virus (FeLV-KT), an exogenous anemia-inducing retrovirus, induced significant macrothrombocytosis and thrombocytopenia during acute infections of cats. The geometric mean platelet volumes of both freshly isolated fixed platelets and ethylenediamine tetraacetic acid-sphered platelets from infected cats were increased, but the ratio of fresh-fixed to ethylenediamine tetraacetic acid-sphered platelet volumes, an estimate of ethylenediamine tetraacetic acid-induced isovolumetric shape change, was normal. Total plasma membrane increased as the platelet volumes increased in FeLV-KT-infected cats, but estimated surface connected canalicular system surface area did not. Platelet concentrations were decreased 2 to 6 weeks after inoculation, but marked macrothrombocytosis resulted in a trend toward increased platelet mass on weeks 5 and 6 after inoculation. Thus, FeLV-KT-induced macrothrombocytosis may serve as a model of impaired platelet volume regulation. The platelet volume and platelet membrane surface area abnormalities found suggest that this model would allow studies of the megakaryocyte/platelet axis, particularly in the area of membrane formation and territorial demarcation.

Animals↗
PubMed1986

Electronic measurement of erythrocyte volume and volume heterogeneity in horses during erythrocyte regeneration associated with experimental anemias.

Anemia was induced in three groups of horses by moderate or severe acute hemorrhage, or by acetyl phenylhydrazine-induced hemolysis (Groups I, II, and III, respectively). Serial hemograms were done on a multichannel automated blood cell counter with histogram capability. Changes in hematocrit, mean cell volume, erythrocyte number, red cell distribution width (RDW), and standard deviation of erythrocyte volume were examined over time. Significant increases in mean cell volume were first detectable by days 17, 20, and 14 and reached maximum by days 43, 41, and 29, in Groups I, II, and III, respectively (P less than 0.05). Increased mean cell volume was interpreted as reflecting accelerated erythrocyte regeneration; however, not all horses with accelerated regeneration had changes in mean cell volume. Estimated erythrocyte production rate correlated poorly with hematocrit nadir and change in mean cell volume (r = 0.37 and r = 0.36, respectively, P greater than 0.05). In some horses effective regeneration occurs without development of macrocytosis. Mean cell volume remained increased after other parameters returned to control values, suggesting that mean cell volume values may provide retrospective evidence of altered erythrocyte turnover. Anisocytosis as indicated by significant increases in the standard deviation was greatest during the early part of the regenerative response, reaching maximum values on days 30, 28, and 21 in Groups I, II, and III, respectively, and began to decrease as homogeneous repopulation with macrocytes occurred. Red cell distribution width increased significantly only in severe hemorrhage and hemolysis groups, reaching mean maximum values of 24.3 on day 20 and of 26.4 on day 21 in Groups II and III, respectively (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Anemia↗
PubMed1986

Hematologic and serum biochemical values for Yucatan miniature swine.

Hematologic and serum biochemical values were determined for healthy, mature Yucatan miniature swine, Sus scrofa. These values were similar to those reported for other breeds of swine. There was no effect on erythrocyte count, hematocrit, MCV, MCH, MCHC, RDW, platelet count, or leukocyte count attributable to sex (p greater than 0.05). Differential leukocyte counts generated on an automated multichannel blood cell counter, having a three part leukocyte differential capability, were compared to 100-cell manual leukocyte differentials. Determination of lymphocyte and non-lymphocyte fractions on this system were not significantly different from microscopic differentials (p less than 0.001). However, the mononuclear cell count did not correlate well with the percentage of monocytes determined manually (r = 0.084, p greater than 0.5). Leukocytes, erythrocytes, and platelets behaved properly with respect to counting thresholds as modified for counting cells of other common domestic species on this automated cell counter.

Animals↗
PubMed1985

Sizing of animal erythrocytes using sulfate based diluent.

Sulfate based cell counting diluent and human erythrocyte size standards were evaluated for electronically sizing erythrocytes of common domestic species. Mean differences between calculated and human cell referenced electronic mean corpuscular volume values were 0, 0.4, 0.8, and 2.1 fl for blood of dogs, horses, cats, and cows, respectively. These differences were statistically significant only for the cat (p=0.029) and cow (p=0.0002). Electronic mean corpuscular volume was measured on multiple lots of human cell control material following calibration with human cells and cells of each of the four species. There were no significant differences between assigned assay values and direct measurements at each calibration (F=0.14, df=29). Sulfate based diluent, used on some automated cell counting systems, appears suitable for sizing animal erythrocytes and commercially available human cell standards are appropriate for calibration of certain systems used in veterinary hematology.

Journal Article↗
PubMed1985

Erythrocyte volume distribution in rainbow trout.

Reference mean corpuscular volume and volume heterogeneity values for erythrocytes of 23 rainbow trout were measured, using an electronic particle counter, and were analyzed, using a particle-size analyzer and microcomputer. The mean (+/- SD) erythrocyte count was 1.5 X 10(6) +/- 0.16 X 10(6) cells/microliter, the mean corpuscular volume was 346 +/- 25 fl, and the mean coefficient of variation of erythrocyte volumes was 29 +/- 2.3%. All erythrogram curves were skewed to the right, representing a mean of 15.6 +/- 3.5% of the total cells counted.

Animals↗
PubMed1984

Platelet concentration and platelet volume distribution in healthy cats.

An electronic particle counter and size analysis system were used to determine platelet count, mean platelet volume (MPV), platelet volume heterogeneity (SD of platelet volumes), and platelet mass values in feline platelet-rich plasma (PRP) prepared by brief centrifugation of blood. Electronic platelet counts correlated well with manual counts done by phase microscopy over a platelet count range of 5,000/microliters to 840,000/microliters (r = 0.93). Variability in manual and electronic counts was not significantly different. However, due to differential stratification of platelet concentration in PRP, electronic counts on aspirated, mixed PRP were significantly less variable (P less than 0.01). Reference values, determined on blood from 25 healthy adult cats, were platelet count: 296,000 to 850,000/microliters; MPV: 11.0 to 18.1 fl; platelet volume heterogeneity: 5.8 to 10.6 fl, and platelet mass: 4.0 to 11.4 microliters/ml of blood. There was a direct relationship between MPV and platelet volume heterogeneity and an inverse relationship between MPV and platelet count. Platelet concentration and size were not constant in different PRP layers. Aliquots of PRP near the top had a significantly lower platelet concentration (P less than 0.001) and lower MPV (P less than 0.001) than did aliquots from near the bottom of the PRP layer. During the 4 hours after sample collection, there was a progressive decrease in platelet count and progressive increase in MPV, but the changes were not significant. When platelets were incubated in counting fluid, there was a slight increase in MPV by 1.5 hours. By 2.5 hours, there was a significant increase in MPV (P less than 0.05).

Animals↗
PubMed1983

Comparison of two automated multi-channel blood cell counting systems for analysis of blood of common domestic animals.

An automated, multi-channel blood cell counting system (S-Plus) was compared to a reference counting system using blood samples from 187 animals of four species. The standard red cell bath aperture current of 150 volts (V) was used during analysis of 75% of the samples. At this setting, all samples with a Mean Corpuscular Volume (MCV) greater than 50 fl had accurate erythrocyte counts. As the MCV decreased below 50 fl, the severity of false low erythrocyte counts and false high MCV values increased. The remaining 25% of samples were analyzed with the red cell bath aperture current increased to 200 V. At this setting, only 5% or less of erythrocytes from animals with normal MCV values(>36 fl)were below the erythrocyte threshold. The red cell distribution width values provided by the S-Plus indicated that equine and bovine erythrocytes have greater anisocytosis than canine and feline erythrocytes. Leukocyte counts were significantly lower on the S-Plus (p<0.01). Canine and equine samples most frequently had platelet size distribution within the S-Plus platelet counting threshold window. Electronic whole blood platelet counting appeared unsatisfactory in cats due to large platelet size and erythrocyte-platelet size overlap. Small platelet size in cattle indicated that further modifications of the red cell bath aperture current would be required to count and size platelets in this species. Following electronic modifications, this state-of-the-art system appears adaptable to hematologic profiling in most species.

Journal Article↗
PubMed1983

Sequential changes in erythrocyte volume distribution and microcytosis associated with iron deficiency in kittens.

Hemograms, erythrocyte volume distribution curves, serum iron and percent transferrin saturation determinations were done on samples from 50 kittens to characterize feline erythrocytic responses between one and ten weeks of age. At one week of age, all kittens had marked macrocytosis and anisocytosis. Most of the macrocytic cells no longer were present by five weeks. Macrocytes were replaced by erythrocytes of normal volume in 30% of the kittens. At five weeks of age, 70% of the kittens had produced microcytic cells which correlated with significantly lower packed cell volume values (p less than 0.02) and mean corpuscular volume values (p less than 0.001). By seven weeks of age, kittens with microcytosis were producing normocytic erythrocytes. Between two and four weeks of age, kittens with microcytosis had significantly lower serum iron and percent transferrin saturation values (p less than 0.01) compared to kittens without microcytosis. Between five and seven weeks of age, all kittens had very high iron values which were significantly greater than those of healthy adult cats (p less than 0.01). Six kittens with low iron values received an iron dextran injection at two to three weeks of age. At five weeks, these kittens had significantly greater mean corpuscular volumes, packed cell volumes (p less than 0.01) and lower percentage of microcytic cells (p less than 0.001) than littermate controls. These data demonstrate that transient microcytosis and anemia observed in kittens is attributable to iron deficiency. It also was demonstrated that erythrocyte volume distribution curves were more sensitive than the mean corpuscular volume in detecting microcytosis in kittens.

Anemia, Hypochromic↗
PubMed1983

Erythrocyte macrocytosis in feline leukemia virus associated anemia.

Using erythrocyte volume distribution histograms (erythrograms), erythrocyte macrocytosis and anisocytosis were quantitated in 139 cats tested for feline leukemia virus group-specific antigen. Feline leukemia virus-negative cats with non-regenerative anemia or normal packed cell volumes had normal mean corpuscular volume values. Uninfected cats with regenerative anemia had prominent significantly increased macrocytosis and anisocytosis (p less than 0.01). Ninety percent of 62 feline leukemia virus-positive cats had altered erythrograms. Thirty-three feline leukemia virus-positive cats with non-regenerative anemia had marked macrocytosis. Their mean corpuscular volume values (mean 60 fl +/- 2 fl standard error, reference range of 37-49 fl) were significantly greater than those of feline leukemia virus-negative cats except for those with regenerative anemia. Feline leukemia virus-positive, non-anemic cats had significantly increased mean corpuscular volume values of intermediate magnitude. Nine adult cats experimentally infected with feline leukemia virus developed non-regenerative anemia with significant increases in mean corpuscular volume and anisocytosis. However, the macrocytosis observed in these cats was considerably less than in naturally occurring feline leukemia virus-positive cats with non-regenerative anemia. These observations indicate there are events in the pathogenesis of feline leukemia virus-associated anemia other than simple erythroid hypoplasia. We suggest that hemolysis and erythrocyte regeneration occur before erythroid hypoplasia and may partially account for macrocytosis observed in the face of non-regenerative anemia.

Anemia, Macrocytic↗
PubMed1982

Erythrocyte volume distribution analysis in healthy dogs, cats, horses, and dairy cows.

Erythrocyte volume distribution curves (erythrograms) were determined on a total of 300 blood samples from healthy dogs, cats, horses, and cattle (dairy cows). An index of anisocytosis was determined for these animals. Erythrograms were highly reproducible, and the mean corpuscular volumes determined from erythrograms compared well with those determined from hemograms. Bovine and equine erythrocyte volumes were found to be stable after the blood was stored at 4 C for 24 hours. Under the same conditions, canine and feline erythrocytes increased slightly in volume. After incubation of blood diluted in isotonic cell counting solution, bovine erythrocytes had stable cell volume, whereas feline, equine, and canine erythrocytes had greater volume.

Animals↗
PubMed1982

Persistent macrocytosis assessed by erythrocyte subpopulation analysis following erythrocyte regeneration in cats.

Serial erythrocyte volume distribution curves were used to characterize changes in erythrocyte subpopulations following the induction of Heinz body hemolytic anemia in cats. Macrocytes produced in response to hemolysis were observed after loss of reticulum. After recovery from hemolysis, a gradual reduction in mean cell size resulted from a combination of macrocyte remodeling and production of normocytic cells. The mean apparent prehemolysis half-survival time for chromium-51-labeled erythrocytes was 13.7 days. There were two components to the posthemolysis survival curve. An initial accelerated loss of label was due to either destruction of posthemolysis macrocytes or loss of cell contents associated with remodeling. The second survival curve component reflected an increased mean apparent half-survival time of 20.2 days. After correction for isotope elution, the latter component reflected cohort-like labeling of relatively young erythrocytes having normal survival for the duration of the experiment. At the beginning for this latter component, 42% of the erythrocytes were macrocytic (mean of 3.3 x 10(6) macrocytes/microliter). Since the number of macrocytes gradually declined during the period of normal survival, it was concluded that these cells entered the normocytic size range. Recognition of persistent macrocytosis is important in the concept of the regenerative response and should be considered in the interpretation of erythrocyte volume distribution curves.

Anemia, Hemolytic↗
PubMed1977

Blood pressure measurement in the dog.

An indirect method of blood pressure measurement was evaluated in 169 dogs, including 114 that were hospitalized because of a variety of diseases, 10 clinically normal dogs presented for neutering, and 45 privately owned, clinically normal dogs. Measurements correlated well with values obtained by simultaneous direct arterial puncture. Normotension was considered to be 130 to 180 mm of Hg, systolic, and 60 to 95 mm of Hg, diastolic. As a group, 20 dogs with advanced renal disease had significant (P less than 0.001) hypertension, compared with the groups of clinically normal dogs. Of 94 dogs with a variety of diseases exclusive of renal disease, 10 had hypertension and 2 had hypotension.

Animals↗
PubMed1975

Hyperammonemia and hepatic encephalopathy in the dog.

Thirteen dogs with hepatic encephalopathy were found to have hyperammonemia and increased retention of plasma sulfobromophthalein. Six dogs had abnormal portal circulatory systems and 4 had heptic disease. The cause of illness was undetermined in 3.

Alanine Transaminase↗