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    The effects of the somatostatin analog octreotide on angiogenesis in vitro

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    This study examined the in vitro antiangiogenic effects of the somatostatin analog octreotide on the growth of human HUV-EC-C endothelial cells and vascular cells from explants of rat aorta cultured on fibronectin-coated dishes or included in fibrin gel. A total 10(-9) mol/L octreotide reduced the mean uptake of 3H-thymidine by HUV-EC-C cells by 37% compared with controls. The 10(-8) mol/L concentration of octreotide inhibited the proliferation of endothelial and smooth muscle cells growing on fibronectin by 32.6% and reduced the sprouting of cells from the adventitia of aortic rings in fibrin by 33.2% compared with controls, as measured by tetrazolium bioreduction and image analysis, respectively. These results demonstrate that octreotide is an effective inhibitor of vascular cell proliferation in vitro

    Teratogenesis and immunosuppressive treatment

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    Despite the potential risks to the mother and fetus caused by immunosuppressive drugs, uneventful pregnancies are now frequent among transplant recipients. Although there is no apparent increase in the type or incidence of malformations in the newborns or evidence of graft dysfunction, pregnancy-related complications, including premature termination and low birth weight, may be more frequent. To prevent graft rejection due to the increased immunologic reactivity of the transplant recipient during pregnancy, it is reasonable to wait 2 years after transplantation before conception, to have stable graft function and to be on low drug doses for maintenance immunosuppression. Among the immunosuppressive agents, corticosteroids may induce a number of treatment-related complications, including diabetes and osteoporosis; however, the incidence of fetal malformations during corticosteroid treatment is about 3.5%, a value close to that of the general population. Among immunosuppressive antibodies, no evidence of developmental toxicity has been demonstrated with basiliximab. On the contrary, some concerns have been raised about azathioprine, since its use has been associated with fetal abnormalities in animals; however, clinical data so far have indicated only a small teratogenic risk. Therefore, immunosuppressive therapy with selected drugs and antibodies does not apparently increase the risk of birth defects and may be continued in pregnancy. Finally, although breast-feeding is not recommended, because of drug transfer into maternal milk, the available clinical data do not support this limitation because of the low amount of drug absorbed by the infant and the absence of clinical toxicity in published case reports

    Hematologic toxicity of immunosuppressive treatment

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    The administration of immunosuppressive agents may be associated with the occurrence of hematologic toxicity, such as anemia, due to bone marrow suppression or hemolysis, leukopenia, and thrombocytopenia. The administration of azathioprine and mycophenolate mofetil is more frequently associated with bone marrow suppression, while hemolytic-uremic syndrome may occur after administration of cyclosporine, tacrolimus, or muromonab (OKT3) and may be associated with the loss of the allograft. Moreover, microangiopathic hemolytic anemia and thrombocytopenia are rare, but potentially severe, complications of immunosuppressive treatment with tacrolimus and cyclosporine; they are characterized by intravascular hemolysis due to mechanical destruction of red cells as a result of pathological changes in small blood vessels. Viral infections (cytomegalovirus), administration of antiviral agents (gancyclovir), inhibitors of angiotensin-converting enzyme and angiotensin II receptor antagonists, antibacterial agents (sulfamethoxazole and trimethoprim), and allopurinol may aggravate bone marrow suppression, particularly when administered with agents that interfere with purine biosynthesis, including azathioprine and mycophenolate mofetil

    Central alpha-2 adrenoceptors regulate central and peripheral functions

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    Central alpha-2 adrenoceptors regulate a variety of functions including blood pressure, gastrointestinal activity, hormonal secretion, sleep-waking cycle, analgesia, anxiety and some aspects of the withdrawal reaction to opioids. Evidence has been provided that clonidine decreases blood pressure, inhibits salivary secretion and reduces gastrointestinal secretion and motility. Several alpha-2 adrenoceptor agonists reduce wakefulness and inhibit paradoxical sleep, whereas novel imidazoline derivatives, such as detomidine, display sedative and analgesic properties which have been related to the activation of central alpha-2 adrenoceptors. Recent data emphasize the importance of somatodendritic alpha-2 autoreceptors compared to presynaptic alpha-2 autoreceptors as physiological modulators of noradrenergic activity in the central nervous system. In addition, increasing experimental evidence has been provided on the relevant role played by central alpha-2 heteroreceptors (presynaptic and somatodendritic) in the regulation of several functions. Some effects mediated by the activation of alpha-2 adrenoceptors are very similar to those following stimulation of mu opioid receptors. This parallelism can be explained, at least in part, by the presence of these receptors on the same neurons on which they exert an inhibitory action mediated by the same cellular mechanisms. This review resumés the most prominent data about the role played by central alpha-2 adrenoceptors in the regulation of overall functions
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