Tissue plasminogen activator and inhibitors of fibrinolysis in malignant melanoma

Various human malignant tumors including malignant melanoma showed an absence of fibrinolytic activity in previous histochemical fibrin studies. In contrast, a tissue plasminogen activator has been isolated both from extracts of melanoma tissues and melanoma cell lines in culture and has been characterized to be a potent plasminogen activator. In an attempt to resolve this apparent discrepancy, we studied biopsies specimens of melanoma, several melanoma cell lines and melanoma xenografts by the immunoperoxidase method. Tissue plasminogen activator was observed in melanoma tissues, cell lines and xenografts, while various inhibitors of fibrinolysis, including alpha 2-antiplasmin, alpha 2-macroglobulin, alpha 1-antitrypsin and antithrombin III, were found intracellularly only in the melanoma tumor cells but not in melanoma cell lines nor in xenografts. We believe that these inhibitors are derived from the blood and are bound to the tissue plasminogen activator within the melanoma cells. Their presence in tumor cells would explain the lack of fibrinolytic activity in melanoma tissues.     

Fatal rupture after successful surgical thrombosis of an abdominal aortic aneurysm

Fatal aortic rupture in a patient 2 weeks after successful thrombosis of an abdominal aneurysm by bilateral iliac artery ligation is reported. The procedure apparently failed to protect the proximal aortoaneurysmal junction, which led to rupture and exsanguination. In view of our present experience, reevaluation of these aneurysm-thrombosing procedures, particularly pertaining to the protection of the proximal aortoaneurysmal junction, is suggested.     

Octreotide dependency and headache: a case report

We report on headache induced by a somatostatin octapeptide analog (octreotide) used for the treatment of acromegaly, This "rebound" headache has severe tension-type characteristics and occurs every 6–8 h. It resolves dramatically within minutes with octreotide administration. This is the first report of headache developing under treatment with octreotide.     

Etiology and pathogenesis of Attention-deficit Hyperactivity Disorder (ADHD): significance of prematurity and perinatal hypoxic-haemodynamic encephalopathy

Attention-deficit Hyperactivity Disorder (ADHD), defined as a disorder of awareness with impul-sivity, has lately been characterized as a dysfunction of the striatum (neostriatum = globus pallidus + putamen). This structure is in a unique position for contextual analysis and samples information from almost the entire cortex through its spiny neurons. The etiology is heterogeneous, with genetic as well as lesional factors. Among the latter, pre- and perinatal events are prominent. Advances in the understanding of the role of fetal circulatory insufficiency with loss of autoregulation and systemic hypotension have drawn attention to the vulnerability of watershed regions, including the striatum. Not only circulatory facts are important for this selectivity, however. The anatomical characteristics, with convergent glutaminergic afferent synaptic transmission from almost the entire cortex contribute to the vulnerability in ischemia-induced liberation of glutamate: The striatum becomes the victim of its virtue. Repeated hypoxic-ischemic events are particularly common in prematurity, a fact which seems to explain the high incidence of ADHD in this patient group. The magnitude of the problem is increasing with the increased survival rate among premature infants.     

PREVALENCE OF MITRAL VALVE PROLAPSE IN HONG KONG CHINESE A CLINICAL AND AUTOPSY STUDY

The prevalence of mitral valve pro.lapse in Chinese was determined by screening 156 heal- thy subjects and by patholobic examination of 86 adult autopsies. Mitral valve prolapse was found in 7.7% in the clinical study and 5.8% in the autopsy study. A slight female preponderance was noted.     

The effects of intravenous prostacyclin in a model of microsurgical thrombosis

Numerous agents have been administered in an attempt to achieve specific biochemical antiplatelet activity. A model of microsurgical trauma was utilized to create a nonocclusive thrombus, similar to what occurs in the postoperative period. Prostacyclin (PGI2) was given in a high intravenous dose which caused in vitro inhibition of platelet aggregation in rats and rabbits. Although hematological and cardiovascular side effects of PGI2 were tolerated, in vivo platelet thrombus formation persisted and constituted 25-75% of the postoperative thrombus. Even though platelets were inhibited by PGI2, other significant stimuli remained at the site of injury for activation and participation of platelets in the formation of a thrombus.