Biomedical subjects

R Mischke

Publications and source records attributed to R Mischke.

At least 73 records · Page 4Linked to original sources

PubMed1997

Optimization of prothrombin time measurements in canine plasma.

OBJECTIVE: To optimize a prothrombin time (PT) method designed for human plasma for use with canine plasma. SAMPLE POPULATION: 100 plasma samples from healthy dogs and 50 plasma samples with reduced activity of the single factors II, V, VII or X. PROCEDURE: Canine plasma samples with various coagulation activity values (100, 75, 50, 25 and 10%: prepared by dilution from a plasma pool [n = 100]) were assayed at various sample dilutions and dilutions of the thromboplastin component of 3 commercial calcium thromboplastin reagents. The sc-named optimized PT test was compared with the standard test with respect to its sensitivity and correlation with the sum of the activity decreases of single factors II, V, VII, and X in relation to the respective reference range. RESULTS: The time intervals between various coagulation activity values, which were small by use of the standard test, could be increased by diluting the sample and substituting fibrinogen, but not by diluting the tissue thromboplastin component of PT reagent. On the basis of 50 abnormal plasma samples, the optimized test had high sensitivity (0.90 to 1.00, dependent on reagent and sample dilution) in contrast to the standard test, which had low sensitivity (0.24 to 0.58, dependent on reagent). Also, correlation with the sum of the activity decreases was closer by use of the optimized (0.90 to 0.93) than the standard (0.58 to 0.84) test. CONCLUSIONS: In contrast to the standard test, an optimized test is suitable as a sensitive screening test of the extrinsic coagulation system in dogs. CLINICAL RELEVANCE: The optimized PT method is easy to perform and, therefore, should be in general use for assay of canine plasma.

Animals↗

PubMed1997

[Cyclosporin A in aplastic anemia in dogs: first results].

Aplastic anemia in the dog is defined as a reduction of marrow activity comprising all three marrow cell lines or selectively of the erythropoiesis. In comparable cases in human medicine an immunogenic etiology is presumed, and a treatment with the immunosuppressant Cyclosporin A is initiated. There are no experiences with this kind of therapy in aplastic anemia of the dog. Four dogs, three with a hypoplasia of the erythropoietic cell line and one with panmyelophthisis, were treated orally for a period of several months with Cyclosporin A 5-10 mg/kg bodyweight bid. In all patients the plasma concentration of Cyclosporin was controlled in regular intervals. Depending on the plasma concentrations the dose was adapted in several cases. Cyclosporin levels between 200 and 600 ng/ml were considered desirable and their efficacy in the therapy of aplastic anemia was examined. In the patient with panmyelophthisis, therapy was not successful. In this case, a marrow intoxication was presumably responsible for the aplastic anemia and the dog was euthanized. In two of the remaining three cases, therapy with Cyclosporin A was successful; the last dog is still being treated with Cyclosporin A at this time.

Anemia, Aplastic↗

PubMed1997

[Importance of cytogenetic investigations in canine leukemias].

Like in man, in neoplastic haematopoietic diseases of the dog genetical changes can be detected cytogenetically. In this study, some cytogenetically characterized cases are presented and discussed against the background of comparable cases reported in the literature. In two out of three patients investigated, one or two extra copies of chromosome 1 were detected. Corresponding changes have also been described in two other cases in the literature.

Animals↗

PubMed1997

Dynamics of haemostasis during the oestrous cycle and pregnancy in bitches.

The blood coagulation status was studied in 31 bitches of different breeds during 33 oestrous cycles and during nine pregnancies. Two other bitches were ovariohysterectomized and received subcutaneous injections of oestradiol benzoate for 7 consecutive days. Blood samples were taken in early and late follicular phases, at ovulation, at day 1 after the end of oestrus as determined by cytology, at days 30, 60, 90 and 120 of metoestrus and in anoestrus. The samples were analysed for the concentrations of fibrinogen, fibrin(ogen) degradation products, as well as for the prothrombin time, the activated partial thromboplastin time, the antithrombin III activity, the number of platelets and the haematocrit. In other blood plasma samples the concentrations of oestradiol and progesterone were measured. In the two bitches that were ovariohysterectomized and received subcutaneous injections of oestradiol benzoate for 7 consecutive days, the coagulation parameters and hormones were examined in blood samples collected at appropriate terms and time intervals as in intact dogs. The significantly increased concentrations of fibrinogen and fibrin(ogen) degradation products, the large number of platelets and the decreased antithrombin III activity observed during the luteal phase of the nonpregnant and pregnant bitches are attributed to direct or indirect effects of the high peripheral progesterone concentrations. In the mid-luteal phase (day 30) this activation was more distinct during pregnancy than in the nonpregnant dogs presumably owing to additional effects of local processes in the uteroplacental area. Influences of high concentrations of oestradiol were not observed either during the follicular phase of the intact bitches or after oestradiol benzoate administration in the ovariohysterectomized dogs.

Analysis of Variance↗

PubMed1997

Effects of low doses of prostaglandin F2 alpha during the early luteal phase before and after implantation in beagle bitches.

Three groups of five beagle bitches were treated three times a day with natural prostaglandin F2 alpha (PGF2 alpha) at a dosage of either 20 micrograms kg-1 bodyweight (days 5-8 of metoestrus), 50 micrograms kg-1 bodyweight (days 5-11 of metoestrus) or 20 micrograms kg-1 bodyweight after detection of pregnancy (days 20-21 after ovulation) for 7 days. A dose of 20 micrograms PGF2 alpha kg-1 bodyweight administered during the early luteal stage could not induce a reliable decrease of progesterone concentrations, while injections of 50 micrograms PGF2 alpha kg-1 bodyweight beginning before implantation resulted in arrest of luteal progesterone production and prevention of nidation in all five bitches. The application of 20 micrograms PGF2 alpha kg-1 bodyweight shortly after implantation induced functional arrest of corpora lutea and led to embryonic or fetal resorption in all cases. In general, the luteolytic effect of low PGF2 alpha doses was insufficient because of the recovery of the corpora lutea seen in nearly all bitches and the prolonged process of embryonic or fetal resorption that increase the risk of uterine disease.

Abortion, Induced↗

PubMed1997

[Antithrombin III activity in health cats and its changes in selected disease].

Measurements of the antithrombin III (AT III) activity in feline plasma with a thrombin dependent chromogenic substrate assay using an automatic analyzer showed a high within run precision. The coefficient of variance was 1.82% (normal AT III activity) or 3.19% (decreased AT III activity), respectively. In comparison with the feline pool plasma the AT III activity in canine plasma was similar (93.7%) and in human reference plasma was lower (71.7%). Respecting healthy cats aged more than three months no distinct influence could be demonstrated on the AT III activity neither of age nor of gender (p = 0.2180). Based on the 2.5%- and 97.5%- quantile the reference range was 83.5-122.5% respecting the total number of healthy cats (n = 138) or 82.6-121.5% concerning the 116 European Shorthair cats. AT III activity of cats infected with feline immunodeficiency virus (n = 37) or teline leukemia virus (n = 20) as well as of cats suffering from different solitary tumors (n = 8) was not distinctly different from the control group (p > 0.05). On the contrary, a significant decrease of AT III activity was found in traumatized cats (n = 20; median = 80.8%, p < 0.0001) as well as in animals with chronic renal failure (n = 20; median = 91.7%, p = 0.0228) which can be mainly attributed to a consumption reaction or excessive renal loss, respectively.

Animals↗

PubMed1997

[Changes in hemostasis in dogs with chronic renal insufficiency].

The study enclosed 30 dogs with severe or end stage chronic renal failure showing distinctly increased concentrations of urea and creatinine. In most of the 15 cases, where a pathologic-histological investigation of the kidney was carried out, a glomerulonephritis was observed (n = 11), partly accompanied by an interstitial nephritis or tubulonephrosis, respectively. Compared to the control group (n > or = 100) the most significant changes were the distinctly increased concentrations of fibrinogen (6.22 [2.95-11.83] g/l; median [minimum-maximum]) and activity of the coagulation factors V (median = 165%), VII (198%), X (176%), VIII:C (154%), and IX (178%) as well as of protein C (147%) (each: p < 0,0001 [Mann-Whitney-Test]). Thereby, the latter does not contribute to hypercoagulability in dogs with chronic renal insufficiency. The activity of antithrombin III was clearly diminished (69[41-112]%), and was closely correlated to the albumin concentration (r = 0.7000; p = 0.001) reflecting the joint renal loss of these proteins of nearly a size. Surprisingly a reagent dependent prolongation of the activated partial thromboplastin time appeared. Against that, a corresponding diminution of the activity of single coagulation factors was demonstrated only seldom, reaching only a small degree, and related almost exclusively to the contact activating system. Compared to the respecting reference range the concentrations of soluble fibrin or fibrin degradation products were increased in 15 or 21 (of 29) samples, and were, thereby, significantly higher than in the control group (p < 0.0001). This reflects the enhanced intravascular coagulation occurring possibly limited to the region of the renal alteration that should be more noticed in therapy.

Animals↗

PubMed1997

[Technical aspects of extraction of platelet concentrates from dogs with an automated cell separator].

The results of this work point out that the cell separator AS 104 (Fresenius AG, Bad Homburg), which is developed to obtain platelet concentrates from human beings, can be used for dogs. The base adjustment of the cell separator for human beings (adjustment I) is useful, because of the high yield [platelet count (median): 1.75 x 10(11)] and quality [low leucocyte- (40/microliter) and erythro count (10 x 10(3)/microliter)]. In addition, there was no clear difference between the base adjustment (adjustment I) and an empirical modification (adjustment II). The platelet count of the donor dog decreased during the separation by approximately 140,000/microliter and reached the initial value after four days. Supplementary, the time course of the haematocrit and the concentrations of albumin, total protein and total calcium of the donor dog were measured. It should be mentioned that the concentrations of ionized calcium distinctly decreased during the separation. Synchronously, the concentrations of ionized calcium and of citrat reached the starting-counts 3-4 hours after the ending of the separation.

Animals↗

PubMed1996

Influence of sample predilution on the sensitivity of prothrombin time in feline plasma.

The prothrombin time (PT) is measured in feline plasma usually by means of a method that has been optimized for measurements in human plasma (standard test). In the present study the sensitivity of this test was investigated in comparison to a modified PT using a human placental thromboplastin. In the modified test, 100 microliter sample predilution (1:5, 1:10, and 1:20) were incubated with 100 microliter of a human fibrinogen solution (2 g/l) until 100 microliter Ca-thromboplastin was added. When measured in 31 samples with a reduced, and 22 samples with an increased activity of the coagulation factors II, V, VII and/or X the modified test showed an increased sensitivity as well as a correlation between PT and the changes in single factor activity which was distinctly closer compared to the standard test. The highest sensitivity was produced by a 1:10 or 1:20 sample dilution. A test procedure modified in this way, is thus, a more reliable screening test for the extrinsic system in cats and should be used for routine diagnostics.

Animals↗

PubMed1996

[Hemophilia B in a mixed breed male dog: treatment of a hemorrhagic crisis with fresh frozen plasma].

A 6 months old male crossbred dog became conspicuous because of a considerable haematoma in the region of the left thigh without recognizable exterior trauma. The results of the screening tests of the haemostatic system (distinctly prolonged activated partial thromboplastin time [aPTT], normal thromboplastin time and platelet count as well as a shortening of thrombin time) yielded a tentative diagnosis of haemophilia. Haemophilia B could be diagnosed on the basis of a distinctly and isolated reduced factor IX activity (8%, reference range: 70-140%). Two infusions with 20 ml/kg BW fresh frozen plasma each caused a clear clinical recovery of the patient. In addition, the efficacy of plasma infusion was documented in vitro by a temporary increase of factor IX activity as well as repeated measurements with the resonance thrombograph and of the aPTT.

Animals↗

PubMed1996

[The effect of the albumin concentration on the relation between the concentration of ionized calcium and total calcium in the blood of dogs].

Based on the results of 367 healthy dogs of different age, it could be demonstrated that the concentration of ionized calcium corrected to the pH-value of 7.4 ([Cai (7.4)]) as well as the concentration of total calcium ([Catot]) clearly decreased with increasing age. The most obvious changes were found during the first four months. The [Cai (7.4)] was not influenced distinctly by sex or by breed. The reference range (2.5-97.5% quantil) for [Cai (7.4)] in heparinized plasma was 1.32-1.51 mmol/l in 4-months- to 1-year-old dogs and 1.22-1.46 mmol/l in dogs older than one year, corresponding to a proportion of Cai to Catot of 44.9-54.9%. A moderately close correlation existed between [Cai (7.4)] and the [Catot] (r = 0.754) (n = 393 adult dogs: 180 healthy animals and 213 unselected patients). A similar correlation coefficient was found between the concentrations of Catot and albumin (r = 0.718) or total protein (r = 0.617), respectively. The proportion of Cai to Catot decreased with an increasing concentration of albumin, whereas [Cai (7.4)] tended to increase. The correction of the [Catot] for albumin did not lead to an increased correlation coefficient for the relation with [Cai (7.4)] (r = 0.676). In addition to albumin concentration, the relation between [Cai (7.4)] and the Catot is primarily influenced by complex-forming ions. This became clear by the transient citrate-induced decrease of [Cai (7.4)] whereas [Catot] increased after infusion of fresh frozen plasma in dogs suffering from diarrhea. This investigation shows the limits of the estimation of calcium homoeostasis on the basis of the [Catot].

Aging↗

PubMed1996

[Hemophilia A in the dog: symptoms, blood coagulation analysis and treatment].

In our patients, haemophilia A was observed in German shepherd dogs and Siberian huskies. Frequently occurring clinical symptoms were excessive bleeding from the gums, when getting adult teeth, and haematomas in the regions of the proximal hindleg, the knee joint as well as the chest or abdominal wall, respectively. The activated partial thromboplastin time (aPTT) as a screening test of the intrinsic coagulation system reflects sensitively also a mildly reduced factor VIII:C activity which may be present for example during substitution therapy. Therefore, the aPTT is well suited for screening for haemophilia A. In haemophilic dogs suffering from hypovolaemic shock due to a considerable acute blood loss, besides the aPTT also the prothrombin time and partly the platelet number were beyond the respective reference range due to loss and consumption of coagulation factors and thrombocytes. For substitution therapy, fresh frozen plasma was used in the first line. Administered at a dose of 15 or 20 ml/kg BW, it caused an increase of factor VIII:C activity by 20 or 33%, respectively. 24 hours after the end of infusion the mean of the remaining activity increase in comparison with the value measured immediately after substitution was 27%. The fast, biphasic elimination of factor VIII:C in some cases required a repeated application until clinical recovery. Desmopressin acetate given at a dose of 1 microgram/kg KGW intravenously or subcutaneously to two dogs each did not cause a distinct increase of the factor VIII:C activity, and is, therefore, not an efficacious supplementary therapy to substitution therapy in haemophilic dogs.

Animals↗

PubMed1995

Investigations of platelet aggregation and platelet counts from stored canine whole blood.

The effects of the long term storage of canine blood at 4 to 6 degrees C in PVC-bags containing CPDA-1 as a stabiliser on platelet aggregation and platelet counts were investigated. Aggregation induced by collagen, adenosine diphosphate or a calcium ionophore was preserved well during the first six hours, but there was then a decrease of 24 to 46 per cent in the ability of the platelets to aggregate, after which during the next three to four weeks of storage there was no further decrease in their aggregation properties. The formation of aggregates of platelets reduced the numbers of platelets counted as single thrombocytes by more than 30 per cent during the first four days. The numbers of platelets recorded varied widely with the counting method used (counting chamber or automatically) and with the ethylenediamine tetra-acetic acid content of the dilution fluid.

Adenine↗

PubMed1995

Evaluation of a prothrombin time optimized for the dog on plasmas with defined coagulation factor deficiency due to coumarin intoxication.

The sensitivity of the standard prothrombin time (PT) was low when measured on 56 plasmas with a reduced activity of the coagulation factors mainly of the prothrombin complex (factors II, VII and/or X) taken from eight dogs at different times of vitamin K1 therapy after coumarin intoxication. This was demonstrable by use of three different Ca-thromboplastins. With the standard test only plasmas with an excessive decrease of coagulation factor activity (sum of activity decrease of the single factors in relation to the respective reference range [SAD] > 100%) were detectable with sufficient reliability. In contrast, by using a method optimized for dogs (1:20 sample predilution, fibrinogen substitution) and respecting the species specific features of coagulation physiology, pathological PT-values were measured in up to 70% of the samples (dependent on the Ca-thromboplastin) with slight reductions of single factor activity (SAD: 11-25%). Significant differences concerning the sensitivity were seen additionally between the different Ca-thromboplastins. Human placenta thromboplastin in particular, but also rabbit brain thromboplastin, were more sensitive than a preparation of recombinant human tissue factor. The correlation between the PT and the SAD was closer when using the optimized method (r = 0.919-0.954) compared to the standard test (r = 0.771-0.862). In contrast to the standard test, the PT optimized for dogs is, therefore, a reliable screening test to recognize a slight reduction in prothrombin complex. It is especially suitable for monitoring of vitamin K1 therapy after coumarin intoxication.

Animals↗

PubMed1995

[The effect of calcium 2+ ions on the decomposition of canine and human fibrin(ogen) by (human) plasmin].

With a row of degradation kinetics with different Ca2+ concentrations and their analysis by the means of nonreducing SDS-PAGE we investigated the dependence of fibrin(ogen) degradation product patterns on the Ca2+ concentration. At man and dog the addition of calcium stabilized from 0.06 mM Ca2+ (2.0 molecules Ca2+/molecule Fibrinogen) certain X- Y- and D-fragments which were not or not in this extent generated by degradation without calcium. The X- and Y-fragments were degraded further by plasmin cleavage at other positions, the greatest D-subfragment (D1) remained stable. As like as known for human fibrinogen the Ca2+ bound on a D gamma-chain position probably prevented the cleavage of a C-terminal part of the gamma-chain. By the addition of growing Ca(2+)-concentrations (from 0.1 mM to 10 mM Ca2+) an additional, increasing D-dimer spot at a molecular weight of 220 +/- 7 kDa was formed owing to progressive activation of the concomitant calcium-dependent transglutaminase (factor XIII). After complete proteolysis of fibrinogen (after 15 min) we observed the formation of D-dimers from canine D1-fragments. At the fibrin degradation the D-dimer was dominating already from 0.1 mM Ca2+ in the degradation assay. Especially the D-fragments, but also the smaller FDP E an -F were generated here in a reduced extent. Several new bands (= 57 kDa) were formed instead, that were probably connected FDP D, -E and -F, crosslinked through the action of transglutaminase.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

[Ionized calcium and total calcium in the cat].

The concentrations of total calcium (Catot), of the biologically active ionized calcium fraction (Caion), and of albumin were measured from the plasma of 92 healthy cats and 154 patients. Only a moderate correlation existed between the concentrations of Catot and Caion (r = 0.718), so that the concentration of Catot reflects the calcium homeostasis only to a limited extent. An essential reason for this lies in the distinct dependence of the Catot on the albumin concentration (r = 0.628). On the basis of the 2.5 and 97.5% quantile of the healthy cats, the reference range for Caion was 1.15-1.37 mmol/l (age group > or = 6 months, < 2 years: 1.23-1.38; > or = 2 years: 1.14-1.35 mmol/l), for Catot 2.49-2.87 mmol/l (2.52-2.92; 2.35-2.81 mmol/l) and the fraction of Caion of the Catot 44.5-50.6%. Like the Catot, the Caion also showed no dependence on the sex. Against that, the distinct dependence on age of these two parameters (p < 0.001), which expresses the decreasing Ca concentration in older animals, should be regarded for a discriminating interpretation of measurement results.

Aging↗

PubMed1995

[Measurements of the activity of the coagulation factors VIII:C, IX,XI, and XII in cats].

Using an optimized test, reference ranges were established for the activity of the coagulation factors VIII:C (72-124%), IX (81-130%), XI (69-134%) and XII (51-142%) in the cat (n = 58 cats, 2.5-97.5% quantile). Compared to a reference curve prepared by using a cat-pool plasma (n = 50), the factor VIII:C activity in humans (commercial human reference plasma) was 7.6%, i.e. the factor VIII:C activity in cats was 13 fold higher than in humans. The values for the factors IX, XI and XII depended distinctly on the dilution step of the human plasma. The activity of the cat in relation to humans was approximately 90% (factor IX), 170% (factor XI) and 135% (factor XII). Two clinically healthy cats who were conspicuous pre-operative because of a distinctly prolonged, activated partial thromboplastin time showed a decreased factor XII activity.

Animals↗

PubMed1995

[Preparation and separation of milligram amounts of canine fibrin(ogen) degradation products (fdp) X, Y, D and E].

In the present investigation we first produced canine fibrinogen degradation products (FDP) following two optimized degradation protocols. These FDP-mixtures, which were alternatively enriched with X and Y fragments or D and E fragments, were purified further to individual FDP X, -Y, -D, and -E with > 95% purity by the means of two low pressure column chromatographic techniques (size exclusion chromatography and anionexchanger chromatography). With this techniques the FDP D could be separated into four different D subfractions. No satisfactory results were yielded by hydrophobic interaction chromatography (HIC) with C5-Alkylsuperose, chromato-focusing and separations with hydroxyapatit. The observed strong binding of fragment E on hydroxyapatit probably points to the maintenance of the calcium binding site on the prepared canine E-fragment.

Animals↗