Establishment and characterization of a new human hepatocellular carcinoma cell line

Summary A human hepatocellular carcinoma cell line (FOCUS—Friendship of China and United States) was derived from a patient with primary hepatocellular carcinoma. This cell line has been in continuous culture over an 18-mo period. The morphological and ultrastructural features of FOCUS are consistent with its neoplastic hepatocellular orgin. FOCUS cells contain aspartate aminotransferase and glucose-6-phosphatase activity. In addition, α₁-antitrypsin, fibrinogen, alpha fetoprotein, and carcinoembryonic antigens were detectble in the cytoplasm of the cultured cells by immunochemical staining techniques. The karyotype of the FOCUS cell is human in origin and it contains human DNA sequences as detected by molecular hybridization analysis. The FOCUS cells do not show evidence of density-dependent inhibition of growth under confluent conditions. Repeated growth curves over an 18-mo period were identical, revealing a doubling time of 42 to 48 h. The malignant potential of FOCUS cells was further demonstrated by their ability to lead to gross tumor formation after subcutaneous infection into nude mice. From one of the solid tumors grown in nude mice, recultured cell lines have been established and found to have properties identical to the original FOCUS cell line. This FOCUS cell line represents an additional model for further investigation of tumor specific antigens and the relationship between hepatitis B virus (HBV) and hepatocellular carcinoma. Preliminary molecular characterization has indicated the existence of integrated HBV sequences within the FOCUS genome.     

Decreased sensitivity of human platelets to PGI2 during long-term intraarterial prostacyclin infusion in patients with peripheral vascular disease — A rebound phenomenon?

During successful treatment of peripheral vascular disease with synthetic prostacyclin no alteration in platelet function was reported (1).In 8 patients infused with synthetic prostacyclin continuously for 7 days intraarterially, the platelet function was monitored. Special attention was drawn to the platelet sensitivity in vitro for PGI₂, which is discussed as an important factor maintaining the hemostatic balance.In all the patients with peripheral vascular disease between 24 and 48 hours after the beginning of the infusion a sudden decrease in platelet sensitivity accompanied by an increase in platelet count could be seen.These dramatic alterations representing probably a rebound phenomenon occurring during long-term PGI₂-treatment might be an explanation for a non-beneficial effect of the treatment and in some cases a limiting factor for the continuation of the infusion itself. It is not clear, if this rebound phenomenon is due to a stimulation of an endogenous inhibitor, lowering the synthesis of a naturally occurring substance acting against this inhibitor or tachyphylaxia.     

Enhanced erythroid burst formation in mice after testosterone treatment

A single administration of testosterone propionate (TP) in ex-hypoxic polycythemic mice induces, at 24 hr after androgen, an amplification of the erythroid burst-forming unit (BFU-E or B) pool in marrow. This phenomenon is not associated with an amplification of the erythroid colony-forming unit (CFU-E or E) compartment and is followed by its depletion. In the other hand, the 36–49 hr rise of erythropoietin (Ep) levels in serum is followed by a 60-hr amplification of the E pool. It is suggested that the latter phenomenon is mediated by enhanced Ep production, whereas the early amplification of the B compartment may derive from a direct influence of TP at the stem cell level.     

Langzeittelemetrie der K?rpertemperatur mit synchroner Bestimmung des Energiestoffwechsels beim Blaunackenmausvogel (Urocolius macrourus) unter Normal- und Lethargiebedingungen (Torpor)

Ohne Zusammenfassung

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Long-term telemetry of body temperature with synchronous measurement of metabolic rate in torpid and non-torpid Blue-naped Mousebirds (Urocolius macrourus)

     

Lysis of autologous human melanoma cells by in vitro allosensitized peripheral blood lymphocytes

Summary Peripheral blood lymphocytes (PBL) of melanoma patients were sensitized in vitro with lymphocytes of a single donor or with a pool of lymphocytes of 5–20 different donors. After 6–7 days, the cytotoxic activity of the sensitized PBL was tested against cultured autologous tumor cells and lymphocytes in a ⁵¹Cr-release assay. Tumor lysis was observed in 13 of 16 cases in which patients' PBL (Pt-PBL) were stimulated by a pool of allogeneic lymphocytes and in five out of seven cases when single sensitization was performed. In no case was lysis of autologous normal lymphocytes or blasts seen. Cultivation of Pt-PBL with irradiated autologous tumor cells never led to the induction of lymphocytes cytotoxic to melanoma cells. Lysability by pool-activated autologous Pt-PBL of fresh cryopreserved tumor cells was compared to that of short-term cultured tumor cells, and no significant differences were observed. Cold-target inhibition experiments indicated that the cytotoxicity of Pt-PBL was tumor-restricted since only autologous melanoma cells but not lymphocytes were able to inhibit the reaction. These results indicate that activation of Pt-PBL is necessary in order to elicit or amplify their antitumor activity.     

Fermentation of Bacillus thuringiensis for exotoxin production: Process analysis study

The exotoxin produced by certain serotypes of Bacillus thuringiensis was used as a means of microbiological control of the larval development of flies. The optimal batch cultivation conditions with respect to pH, temperature, aeration, agitation, and initial concentration of growth-limiting substrate were determined. A dynamic model describing the process was designed and fitted to the experimental data. The application of a method for estimating exotoxin and bacterial concentrations from on-line measurable quantities such as oxygen consumption and heat production is presented.     

Differentiation of 2-cell and 8-cell mouse embryos arrested by cytoskeletal inhibitors

Mouse embryos at the 2-cell stage were cultured in the presence of cytochalasin B (CB), cytochalasin D (CD), colchicine (COL) or colcemid (COM) for up to 72 h. Cleavage was arrested in the 2-cell and 8-cell embryos cultured in CB or CD but the blastomeres continued to differentiate, since chromosome replication occurred in the blastomeres at approximately the same time as control embryos underwent cleavage; an increase in the incorporation of [³H]uridine into RNA was also detected. Furthermore, the cleavage-arrested embryos acquired the necessary information to undergo morphogenesis; these embryos when explanted to fresh medium after 48 h culture in CB or CD underwent compaction within 15–60 min and started to cavitate to produce trophoblastic vesicles within 5–6 h at the same time as when the control embryos were undergoing compaction and beginning to form blastocoelic cavities. In contrast, the embryos arrested in the presence of COM or COL showed none of these differentiative, biochemical or morphogenetic changes. Hence, differentiation of blastomeres and morphogenesis is apparently coupled with nuclear divisions and the information does not reside within the blastomeres at the 2-cell or 8-cell stage. The trophoblastic vesicles produced after cleavage arrest subsequently gave rise to only trophoblast giant cells and no embryonic derivatives were detected.     

Energy transduction in photosynthetic bacteria. VIII. Activation of the energy-transducing ATPase by inorganic phosphate

ATPase activity and ATP-induced energization of photosynthetic membranes from Rhodopseudomonas capsulata are stimulated by phosphate; the maximum stimulatory effect occurs at a concentration between 1 and 2 mM.The sensitivity of the ATPase to oligomycin increases in the presence of phosphate since all the P_i-stimulated activity is inhibited by this antibiotic. Aurovertin, which has no effect on ATPase in the absence of phosphate, inhibits completely the activity elicited by this anion.The addition of P_i induces a substantial increase in the V of ATPase activity without changing the affinity of the enzyme for ATP or ADP.Arsenate, at the same concentrations, produces effects very similar to those of phosphate. The stimulation by arsenate of the transfer of energy from ATP to the membrane suggests a non-hydrolytic role of this anion as a modifier of the ATPase activity.     

NMR studies of prebiotic polypeptides

Several polypeptides prepared by means of pyrocondensation have been the subject of structural investigations. Attention has been focused on the constitutional characterization of homo-and co-polymers containing Asp and Glu residues, whose role is essential for the formation of the so-called proteinoids. Contrary to the literature data based on chemical degradation, nmr studies show conclusively that in thermal poly-aspartic acid only β-peptide linkages are present. This result casts serious doubt on the role thermal condensation might have played in prebiotic polypeptide syntheses.