Changing activation sequence in the embryonic chick heart. Implications for the development of the His-Purkinje system

Viruses that establish persistent infections in their host, such as herpesviruses, adenoviruses or HIV, express proteins designed to pre-empt or evade recognition and elimination by MHC class I restricted CD8+ T lymphocytes. Notable discoveries during the annual period of review have demonstrated that, in principle, each single step within the MHC class I pathway of antigen processing and presentation is fair game for manipulation by viral functions. The viral factors that are natural inhibitors of this pathway have been instrumental for the elucidation of the distinct molecular mechanisms that are exploited by viruses. The viral stealth strategies that downregulate MHC class I protein surface expression may lead, however, to a higher susceptibility of virus-infected cells to natural killer cell activity. Strikingly, there is evidence that some viruses counteract increased natural killer cell recognition by expressing viral MHC class I homologues that function as surrogate inhibitors of natural killer cell activity.     

Phase II study of combined levamisole with recombinant interleukin-2 in patients with advanced malignant melanoma

Adoptive immunotherapy (AI) with interleukin-2 (IL-2) and lymphokine-activated killer cells (LAK) is an antineoplastic modality in which immune-activated cells are administered to a host with advanced cancer in an attempt to mediate tumor regression. Levamisole (LEV), an immune stimulant, has been suggested to have therapeutic effectiveness in a variety of cancers. After a phase I trial of recombinant IL-2 plus LEV, a phase II trial of this combination was conducted in patients with advanced malignant melanoma. Nineteen patients were entered in the trial. They received IL-2 at 3 x 10(6) U/m2 subcutaneously daily x 5 plus LEV 50 mg/ m2 orally three times daily (p.o. t.i.d.) x 5. Patients were reevaluated at four-week intervals. None of the patients achieved a partial or complete regression (PR, CR). The median time to treatment failure (refusal, progression, or off study due to toxicity) was 56 days. Grade IV toxicities included vomiting (3 patients), lethargy (1 patient), and musculoskellar pain (1 patient). This regimen is not recommended for further testing in patients with advanced malignant melanoma.     

Subunit structure and function of porcine factor Xa-activated factor VIII

Factor Xa and thrombin (factor IIa) activate factor VIII (fVIII) by different proteolytic pathways. Thrombin cleaves fVIII at Arg372 between the A1 and A2 domains, at Arg740 between the A2 and B domains, and at Arg1689 between the B and A3 domains to form an A1/A2/A3-C1-C2 heterotrimer. We now report a stable porcine fVIIIaXa preparation obtained by Mono S HPLC at pH 6. NH2-terminal sequence analysis of purified subunits of fVIIIaXa revealed that factor Xa cleaves fVIII at Arg219 within the A1 domain and at Arg490 within the A2 domain, as well as at Arg372, Arg740, and Arg1689. Analytical ultracentrifugation of the fVIIIaXa preparation yielded results consistent with a single, 148 kDa species, similar to previous results with fVIIIaIIa [Lollar, P., & Parker, C. G. (1989) Biochemistry 28, 666-674]. Thus, the major species in the fVIIIaXa preparation contains five subunits, including fragments of the A1 and A2 domains that remain noncovalently bound. Fluorescence anisotropy measurements indicated there was no difference in the affinity of fVIIIaXa and fVIIIaIIa for a fluorescent dye-labeled, active-site-blocked derivative of porcine factor IXa. Additionally, the fVIIIaXa preparation bound dye-labeled factor IXa with 1:1 stoichiometry, indicating that all fVIIIaXa molecules in the preparation can bind factor IXa. However, fVIIIaXa had 4-fold less procoagulant activity than fVIIIaIIa. Kinetic analysis of fVIIIa cofactor activity using purified factor IXa and factor X suggested this difference is due to greater activity of fVIIIaIIa relative to fVIIIaXa within the intrinsic fXase complex, rather than a difference in their stabilities.     

Approximations of open quotient and speed quotient from glottal airflow and EGG waveforms: effects of measurement criteria and sound pressure level

A sample of speech acts in everyday discourse referring to persons or events having to do with the term mental retardation was analyzed in order to investigate the belief that language use both constructs and reflects cultural norms that define the social roles of persons reduced to object status through categorical membership. Speech acts gathered suggest four emergent themes: the discourse of category membership, the dichotomy of normal and abnormal, issues of place and space, and fear. These themes were explicated from a social constructionist perspective, displaying the way speech acts construct mental retardation and subvert individuals with the label into demeaned and ridiculed objects of cultural fear.     

Neuroendocrine differentiation is an independent prognostic factor in chemotherapy-treated nonsmall cell lung carcinoma

BACKGROUND: Neuroendocrine differentiation can be identified in 10-30% of patients with nonsmall cell lung carcinoma (NSCLC) by immunohistochemical or electron microscopic techniques. However, its clinical significance is not well established. METHODS: Tumors from 107 patients with Stage IIIA, IIIB, and IV NSCLC treated with cisplatin/etoposide with or without hydrazine in the North Central Cancer Treatment Group and Mayo Clinic protocols were analyzed immunohistochemically with antibodies to chromogranin A (CGA), Leu 7 (CD 57), and synaptophysin (SY). These results were compared with clinical outcomes. RESULTS: Keratin AE1/AE3, used as a control, was positive in 99.1% of cases; 34.6% had positive staining for at least 1 neuroendocrine marker, and 11.3% had positive staining for 2 or more markers. CGA was positive in 4.7%, Leu 7 in 18.7%, and SY in 24.3% of cases. A significant increase in survival was seen in patients with tumors expressing any one neuroendocrine marker or any combination of neuroendocrine markers (P < or = 0.01). There was no correlation between the presence of neuroendocrine differentiation and either response to chemotherapy or time to disease progression (P > 0.3), nor was there any correlation between chemotherapy response, time to progression, or survival with staining intensity or percent of cells positive per case. CONCLUSIONS: Neuroendocrine differentiation may be of prognostic significance in patients with advanced stage NSCLC treated with chemotherapy.     

Anti-inflammatory mystixin peptides inhibit plasma leakage without blocking endothelial gap formation

Mystixins are synthetic peptides that inhibit plasma leakage after tissue injury. We sought to determine the mechanism of the antileakage effect of mystixins, with particular reference to the formation of endothelial gaps in postcapillary venules. Intravenous administration of mystixin-7, a prototype heptapeptide (p-anisoyl-Arg-Lys-Leu-Leu-D-Thi-Ile-D-Leu-NH2), decreased Evans blue leakage induced by substance P (5 microg/kg i.v.) with an ED50 (95% confidence limits) of 130 (76-211) microg/kg in trachea and 52 (27-100) microg/kg in skin of anesthetized F344 rats. Leakage was decreased without a reduction in the number or size of endothelial gaps, visualized by silver deposits after silver nitrate staining. The number of silver deposits per tracheal endothelial cell was 11.4 +/- 0.2 (mean +/- S.E.) after vehicle pretreatment vs. 13.0 +/- 0.8 after mystixin-7 pretreatment (100 microg/kg i.v.). Silver deposit diameter was unchanged at 1.4 +/- 0.1 micron. Mean arterial blood pressure dropped by a maximum of 38% from baseline for approximately 10 min after mystixin-7 (100 microg/kg i.v.), then recovered to a plateau at about 13% below baseline. The antileakage effect of mystixin-7 pretreatment in vivo was also demonstrated in aldehyde-fixed vessels perfused in situ with Evans blue at constant flow (skin, 79% reduction; trachea, 49% reduction), which suggests that mystixin can reduce leakage independent of its hypotensive effect. We conclude that the antileakage effect of mystixin does not depend on reducing the number or size of endothelial gaps, but instead could be caused by residual hypotension, which reduces the negative interstitial fluid pressure toward zero, or clogging of endothelial gaps.