Biomedical subjects

A Deniz

Publications and source records attributed to A Deniz.

12 recordsLinked to original sources

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↗

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

[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

[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

[Effect of acetylsalicylic acid on platelet aggregation and capillary bleeding in healthy cats].

The influence of acetylsalicylic acid (ASA) in vitro and in vivo on several parameters of the hemostatic system was evaluated in healthy cats. The aggregation response of cat platelets in vitro was not influenced by 10 micrograms ASA/ml plasma, whereas ASA concentrations of 35, 70, 100 micrograms/ml and of 1 mg/ml consistently inhibited the platelet aggregation induced by 0.1 (n = 4 cats) and 0.25 micrograms collagen/ml (n = 6 cats). The aggregation response to ADP and thrombin was partially (n = 2) or completely (n = 8) inhibited by an ASA concentration of 5 mg/ml. Administration of ASA at a dosage of 10 and 25 mg/kg BW orally and intravenously yielded a plasma concentration of salicylic acid of 30-42 micrograms/ml (10 mg/kg BW) and 50-70 micrograms/ml (25 mg/kg BW). All the dosages of ASA produced an inconsistent inhibition of the collagen-induced platelet aggregation (1/5 and 2/5 for the respective groups), whereas the response to ADP and thrombin was not altered. Capillary bleeding time was not significantly altered after the ASA administration. Platelet count and screening tests were not influenced by ASA application. According to the results of this study, ASA as a platelet aggregation inhibitor is not useful for the prophylaxis of thromboembolism in cats.

Adenosine Diphosphate↗

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

[Applicability of activated partial thromboplastin time (APTT) as a screening test of milk to medium deficiencies of coagulation factors in cats].

The present investigation examined if the aPTT shows sufficient sensitivity for single factor activities also in cats when measured with the test optimized for humans using a commercial reagent. Comparative measurements were done with different modifications of the aPTT (sample predilution, addition of fibrinogen). Measurements of the aPTT using different methods and the activity of the coagulation factors II, V, X, VIII, IX, XI, and XII were performed in 42 healthy cats in order to determine the reference ranges. The same measurements were done on 21 cat plasmas where at least one of the coagulation factors was diminished in relation to the corresponding reference range. The conventional aPTT reflected the decrease in coagulation factor activity in each of the 21 plasmas by prolongation above the reference range (14.6-24.4 s). The test thus possesses high sensitivity and is a suitable screening test also for the cat. In contrast, in tests with sample predilution the sensitivity was lower (3-4 false negative results). This was probably caused by the distinct increase of the range of the reference values.

Animals↗

PubMed1995

[Automatic cell counting in cat blood].

The usability of the haematology analyzers ¿F-800¿ and ¿System 9000+¿ was investigated in cats using 40 blood samples. Reference measurements were done with a haemocytometer or the microhaematocrit method. Reliable leukocyte counts were measured with the analyzer F-800 in cases only, when the histogram rendered possible a clear demarcation of the leukocyte curve (r=0.97, n=25). With the analyzer System 9000+ a changed basic adjustment of the inferior discriminator (49 fl) vouched for a close correlation with the values measured visually (r=0.94). The volume distribution curves of the erythrocytes and thrombocytes which were partly overlapping allowed an approximate counting of the thrombocytes with both analyzers only of one half of the samples. The inaccuracy resulting from the inexact separation had only a relatively unimportant effect on the automatically measured erythrocyte count due to the numerical relation of erythro- and thrombocytes. Here at a close correlation to the haemocytometer method (r=0.95) was found as well as slightly higher values with the automatic counting. The haematocrit measured with the analyzer F-800 and to a smaller extent by the use of the System 9000+ lay distinctly higher in relation to the values measured by microhaematocrit, when the analyzers were calibrated with human standards. Besides a species specific calibration of the haematocrit and a particular basic adjustment for leukocyte counting with the analyzer System 9000+, the use of the investigated haematology analyzers on feline blood requires an individual estimation of the histograms and removing of the discriminators as well as frequently a repetition of the leukocyte- and thrombocyte counting with a haemocytometer.

Animals↗

PubMed1994

[Optimized methods for measuring coagulation factors II, IV, VII and X in cats].

Since the single factor activity of the cat differed in part distinctly from humans (factor II: 94%, factor V: 500%, factor VII: 125%, factor X: 62%) the method had to be optimized, above all to exclude an influence of a reactive increased factor V-activity on the results of the other coagulation factors. Dilution series of cat pool plasma (CPP) (n = 50 cats) showed, that a commercial human placenta thromboplastin was more suitable as activating reagent than rabbit brain thromboplastin. Using the required sample predilution (1:40), measurements with the latter reagent were more precise when measured on the relation between the imprecision and the time interval between different CPP-dilution steps. Reference curves were prepared for CPP using the optimized method and human placenta thromboplastin (50 microliters 1:40 prediluted sample and 50 microliters deficient plasma were incubated at 37 degrees C for 1 minute, addition of 200 microliters Ca-thromboplastin) and reference ranges were calculated using the values of 57 cats (factor II: 74-126%, factor V: 42-184%, factor VII 56-150%, factor X: 65-143%).

Animals↗

PubMed1988

Serum androgen levels after streptozotocin administration in the male rat.

Serum levels of testosterone and dihydrotestosterone were measured in control and diabetic animals 5, 10 and 15 days after streptozotocin administration. The diabetic state produced a marked reduction in serum androgen levels 10 and 15 days after streptozotocin administration. Insulin treatment partially restored the circulating androgen levels when administered to diabetic rats.

Animals↗

PubMed1988

Functional activity of rat testicular cells in culture.

Testicular cells from adult hypophysectomized rats were cultured for 10 or 12 days, and the effect of treatment with hCG (10 ng/ml) on testosterone and progesterone production and the activity of the Leydig cell enzyme, 3 beta-hydroxysteroid dehydrogenase, were studied. Regardless of hormone treatment, on 4th day in culture a decline in the steroidogenic activity of cultured cells could be observed. Treatment with hCG resulted in stimulation of steroidogenesis on days 6 to 10 in culture, as measured by testosterone and progesterone production. Hormone treatment stimulated or inhibited the enzyme activity depending on the presence or absence in the culture medium of 10(-6) M spironolactone, an inhibitor of 17 alpha-hydroxylase, or an anti-androgen, cyproterone acetate.

3-Hydroxysteroid Dehydrogenases↗