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Programmed cell death of non-nucleated blood cells - platelets - could be associated with pathophysiology of oncologic and oncohematologic diseases. It contributes to both bleedings (caused by the thrombocytopenia, which is induced by elimination of the platelets) and thrombosis (caused by the processes of blood coagulation on the surface of phosphatidylserine exposing platelets). Here we characterized functional responses of platelets from the patients with various oncological disorders undergoing chemotherapy and compared them to the platelets from the healthy donors and platelets pre-incubated with apoptosis inducer ABT-737. Some patients exhibited diminished capability of platelets to aggregate. Immunophenotyping of these platelets revealed their pre-activation in comparison to the platelets from the healthy donors. Calcium signaling analysis revealed that in the patient-derived platelets, as well as in the apoptotic platelets, intracellular calcium levels were increased in resting cells. However, moderate level of this increase together with weak expression of phosphatidylserine allows us to assume that apoptotic processes in the circulating platelets from the patients are limited.

Platelets are anucleate blood cells with reported roles in hemostasis and immune responses, which possess a functional receptor for bacterial lipopolysaccharides (LPSs), the well-known inducers of inflammation. However, LPSs effects on platelets are contradictory. Here we aim to investigate mechanisms of platelet functioning in the presence of LPS and to find the cause of the discrepancy in the previously published data. Cell activity was analyzed by flow cytometry, western blotting, and aggregometry. Thrombus growth was assessed by fluorescent microscopy. LPS' activity was checked by their capability to induce PMN activation. However, LPSs did not substantially affect either thrombus growth in flow chambers, irreversible platelet aggregation, or platelet responses to strong activation. Platelet aggregation in response to 1 μM of ADP was significantly inhibited by LPSs. Flow cytometry analysis revealed that platelet activation responses to weak stimulation were also diminished by LPSs, while VASP phosphorylation was weakly increased. Additionally, LPSs were capable of inhibition of ADP-induced P2-receptor desensitization. Incubation of platelets with a pan-PDE inhibitor IBMX significantly enhanced the LPSs-induced platelet inhibition, implying cAMP/cGMP dependent mechanism. The discrepancy in the previously published data could be explained by LPS-induced weak inhibition of platelet activation and the prevention of platelet desensitization.

The structure of nephrons in 83 species of fishes, amphibians, and reptiles was investigated by microdissection. Glomerular diameter, nephron length, length of nephron segments, and the ratios between glomerular size and nephron length are presented. In diifferent groups of fishes (Elasmobranchii, Acipenseridae, Teleostei), the adaptation to freshwater or seawater environment may lead to diverse changes of nephron structure. The kidneys of euryhaline teleosts capable of living in fresh water may be aglomerular, as are those of some marine fishes. In contrast, the diameter of glomeruli in some marine fishes is larger than in true freshwater fishes. In amphibians, the adaptation to freshwater environment, as in teleost fishes, has led to different changes of nephron structure. The size of glomeruli in freshwater reptiles is larger in comparison to terrestrial animals, and the distal tubule in desert and freshwater reptiles is longer than in nondesert species. This probably reflects the adaptive changes of the reptilian nephron to freshwater and desert environments. The results of this study show that the nephron structure of lower vertebrates is predominantly determined by the different environments they occupy rather than by progressive changes within the vertebrate sequence. © 1994 Wiley-Liss, Inc., (Copyright © 1994 Wiley-Liss, Inc.)

The corticosteroid, triamcinolone, was examined as a potential antagonist for the nephrotoxicity of cisplatin in female Wistar rats. The changes in renal function and renal morphology were assessed on the 3rd day after administration of cisplatin (7.5 mg/kg BW) and in animals given triamcinolone retard (4 mg/kg BW) 6 h before administration of cisplatin. Pretreatment with triamcinolone resulted in much less severe changes in renal function after cisplatin administration (serum urea: triamcinolone plus cisplatin 14.29 +/- 1.90 mg/l, cisplatin alone 21.60 +/- 2.34 mg/l, p < 0.05, control 2.78 +/- 0.19 mg/l, serum creatinine: triamcinolone plus cisplatin 0.21 +/- 0.02 mg/l, cisplatin alone 0.30 +/- 0.02 mg/l, p < 0.05, control 0.06 +/- 0.01 mg/l). In contrast to cisplatin-treated animals in triamcinolone-pretreated rats alterations of water content were found neither in renal cortex (triamcinolone plus cisplatin 3.39 +/- 0.16 g/g dry weight, cisplatin alone 4.07 +/- 0.07 g/g dry weight, control 3.07 +/- 0.07 g/g dry weight) nor in outer medulla (triamcinolone plus cisplatin 4.20 +/- 0.22 g/g dry weight, cisplatin alone 4.98 +/- 0.21 g/g dry weight, control 3.84 +/- 0.11 g/g dry weight) compared to control. The structure of the kidney following cisplatin administration demonstrated extensive lesions of S3 segments of the proximal tubule. The changes in proximal convoluted tubules were widespread and ranged from the decrease of the amount of microvilli to loss of brush border or even to cell death. In triamcinolone-pretreated rats the structure of the cortex appeared to be virtually normal and tissue of medulla was only slightly damaged.

The possibility of a slow, longer term deterioration in renal function following the administration of cisplatin has been little studied in animal models. To obtain data on this we have examined renal function and histopathology at 30 days post i.p. cisplatin (5 mg/kg) treatment in female Wistar rats with and without the administration of hydroxyl-containing dithiocarbamates as a protective measure. In contrast to the studies terminated at shorter times, the degree of protection furnished by the use of dithiocarbamates at longer times post-treatment is less impressive. Results suggest that a continuing deterioration in renal function occurs at times greater than 1 week post-treatment when such dithiocarbamates are administered at 1 and 3 h post cisplatin. This was evidenced in both several measures of renal function and in the histopathology of the S3 segment of the proximal tubule.

Unlike mammals with renal reabsorption of lithium (Li+), in freshwater and, particularly, marine teleosts net secretion of this trace element by kidneys was discovered. The ratio of Li+ natural concentration (measured by mass spectrometric isotope dilution technique) in urine to that in blood plasma--(U/P)Li--lies in the range 2-6 in the freshwater species and between 5 and 14 in marine species, i.e. as a rule it is essentially higher than the inulin concentration index (U/P)In. It is supposed that the in vivo observed lithium net secretion in whole kidney reflects and quantitatively estimates Na+ and water secretion in renal proximal tubules of teleosts.