Progression of canine mammary tumours as reflected by DNA ploidy in primary tumours and their metastases

Thirty dogs with metastasizing mammary tumours (carcinomas, n = 22; sarcomas, n = 8) were necropsied. Flow cytometric DNA analysis was carried out on frozen primary tumours and on selected metastases from the dogs. Ductular carcinomas (n = 13) had a varying growth pattern, in terms of histology, in both the primary tumours and metastases and between different metastases. The different types of DNA ploidy, including hypodiploidy, in the primary ductular carcinomas were also seen in the tumour metastases. Dogs with primary anaplastic carcinomas (n = 7) had multiple metastases, which were in most cases near-diploid or hyperdiploid. Two dogs had spindle-cell carcinomas, which were hypodiploid in both the primary tumour and the metastases. The DNA ploidy in the metastases was retained in 16 of the 22 dogs with primary carcinomas. Fibrosarcomas (n = 5) showed different types of DNA ploidy. In two of the three dogs with diploid or near-diploid osteosarcomas, the DNA ploidy was retained in the metastases. There was a statistically significant association between mammary tumours and metastases (P = 0.0001) in terms of both histological diagnosis and DNA ploidy. The association was retained when the carcinomas were tested separately (P = 0.0001); in the sarcomas it was retained weakly in terms of histology (P = 0.0183) but not DNA ploidy (P = 0.6659). The retention of the DNA ploidy in most carcinoma metastases indicated that selection of DNA ploidy had taken place prior to metastasis. The differences in patterns of DNA ploidy between ductular and anaplastic carcinomas may reflect different pathogenesis in these types of canine mammary tumour.

Coacute heparin: a new simple monotest for monitoring heparin treatment

Anti-Factor Xa methods have been generally accepted for the monitoring of heparin treatment, mainly due to their sensitivity to LMW heparin and excellent performance on automated equipment. When such equipment is not available, as in small laboratories or on the night shift, there is a need for a simple manual method. In the present method activated Factor X and a chromogenic peptide substrate are colyophilized in plastic cuvettes under conditions that avoid reaction between the two constituents. The assay is performed accordingly: Plasma (200 microL) is diluted in 3.0 mL predispensed Tris buffer containing dextran sulfate 8000 to avoid losses of heparin due to, for example, platelet factor 4. The diluted plasma (400 microL) is added to a cuvette. The reagents are rapidly dissolved and the reactions start. The rate of Factor Xa inhibition is proportional to the heparin activity. During the incubation, the substrate is also hydrolyzed by the remaining enzyme. This combination of reactions is insensitive to changes in temperature, making it possible to perform the assay at room temperature. After 10 minutes incubation, the reaction is stopped by adding 400 microL of 5% acetic acid. The absorbance is read in a well-calibrated photometer and the results plotted on a graph available in the kit. Eleven commercially available heparins have been tested with the assay and they all fell within a narrow range, showing the relevance of using a standard plot for all heparins. The LMW heparins behaved differently and it may also be that they demand different therapeutic strategies.

Glucose-insulin-potassium (GIK) prevents derangement of myocardial metabolism in brain-dead pigs

Brain death is associated with neuroendocrine changes resulting in reduced myocardial glycogen content. The purpose of this study was to investigate the effects of glucose-insulin-potassium (GIK), on myocardial metabolism in brain-dead pigs. Sixteen brain-dead pigs were given GIK infusion (n = 8), or Ringer solution (n = 8). At end-point (7 h post brain death) arterial concentrations and myocardial arteriovenous (a-v) concentration differences of glucose, lactate and free fatty acids (FFA) were assessed, and myocardial biopsy specimens were taken from the right atrium and left ventricle. Biopsies were also taken from five normal pigs. Myocardial glycogen content in the GIK group was significantly higher compared to the control group, but comparable to the non-brain-dead animals. There was a higher and significant myocardial uptake of glucose and lactate in the GIK group compared to the controls. Plasma levels of FFA were significantly lower in the GIK group, and the myocardial uptake of FFA was 5 times higher in the control group compared to the GIK group. There were no significant differences in hemodynamic variables among the groups. In conclusion, intravenous supply of GIK to brain-dead pigs results in increased myocardial glycogen content and seems to prevent abnormal myocardial metabolism, which may have clinical implications for the myocardial protection of donor hearts.