Release of fibroblast growth factor-1 by human squamous cell carcinoma correlates with autocrine cell growth

Summary A squamous cell carcinoma cell line Nakata proliferated in serum-free culture and was not responsive to exogenous fibroblast growth factor-1 (FGF-1). Immunostaining revealed that Nakata cells expressed FGF-1 in their cytoplasms and nuclei. Two molecular mass species of FGF-1 (16 and 18 kDa) were identified in cell extracts by Western blot. These cells also expressed high-affinity FGF-1 binding sites (Kd=360 pM, 28 000 sites/cell). The results of cross-linking with [¹²⁵I]FGF-1 demonstrated the presence of two bands with molecular masses of 160 and 140 kDa. The addition of FGF-1 specific antisense oligonucleotides at 25 μM to Nakata cells resulted in an 82% inhibition in cell growth and suppressed FGF-1 expression. This effect was dose-dependent and specific, because sense oligonucleotides were ineffective in inhibiting cell growth. In addition, Nakata cell growth was suppressed by an anti-FGF-1 neutralizing antibody, which resulted in a 52% inhibition at 8 μg/ml. These results demonstrate that Nakata cells produce FGF-1, and indicate that this growth factor acts in an autocrine manner by interacting with FGF-1 binding sites on Nakata cells.     

Cytokine regulation of cell-to-cell interactions in lymphokine-activated killer cell cytotoxicity in vitro

The permanent pancreas carcinoma cell line, PCI-24, was developed in order to analyse cytokine regulation on pancreas carcinoma and lymphokine-activated killer (LAK) cell interaction. PCI cells expressed ICAM-1 and HLA-ABC, but not HLA-DR antigens. PCI cells showed augmented ICAM-1 and HLA-ABC expression when incubated with interferon (IFN) and tumour necrosis factor . A similar but weak augmentary effect on the HLA-ABC and ICAM-1 surface expression was seen with interleukin-1 treatment. Natural attachment of LAK to PCI cells was augmented by recombinant IFN in close association with ICAM-1 up-regulation on PCI cells. In addition, natural attachment was significantly inhibited by anti-LFA-1 and anti-ICAM-1 antibody treatments. Cytotoxicity of the LAK cells against PCI cells was also significantly inhibited with the same treatment. Thus, the attachment of LAK cells to PCI cells through LFA-1/ICAM-1 molecules appeared to be essential for the cytotoxicity for PCI cells. Pretreatment of PCI cells, but not of LAK cells, with IFN or other cytokines resulted in a decrease of susceptibility for LAK cell cytotoxicity. The decreased susceptibility inversely correlated with HLA-ABC expression on the PCI cells. The collective evidence indicates that, although LAK cell attachment to pancreas carcinoma cells through the LFA-1/ICAM-1 molecule is augmented by IFN, IFN treatment of pancreas carcinoma cells reduces LAK cell cytotoxicity possibly through an increase in HLA-ABC or a regulation of molecules closely associated to HLA-ABC expression.     

Growth Characteristics and Intraspecies Host Specificity of a Large Virus Infecting the Dinoflagellate Heterocapsa circularisquama

The growth characteristics and intraspecies host specificity of Heterocapsa circularisquama virus (HcV), a large icosahedral virus specifically infecting the bivalve-killing dinoflagellate H. circularisquama, were examined. Exponentially growing host cells were more sensitive to HcV than those in the stationary phase, and host cells were more susceptible to HcV infection in the culture when a higher percent of the culture was replaced with fresh medium each day, suggesting an intimate relationship between virus sensitivity and the physiological condition of the host cells. HcV was infective over a wide range of temperatures, 15 to 30°C, and the latent period and burst size were estimated at 40 to 56 h and 1,800 to 2,440 infective particles, respectively. Transmission electron microscopy revealed that capsid formation began within 16 h postinfection, and mature virus particles appeared within 24 h postinfection at 20°C. Compared to Heterosigma akashiwo virus, HcV was more widely infectious to H. circularisquama strains that had been independently isolated in the western part of Japan, and only 5.3% of the host-virus combinations (53 host and 10 viral strains) showed resistance to viral infection. The present results are helpful in understanding the ecology of algal host-virus systems in nature.     

Efficient production of IGG human monoclonal antibodies by lymphocytes stimulated by lipopolysaccharide,pokeweed mitogen,and interleukin 4

Summary Extensive screening of the mitogens lipopolysaccharide (LPS), pokeweed mitogen (PWM), andStaphylococcus aureus Cowan I (SAC I), alone and in combination and with and without interleukin (IL) was performed forin vitro activation of regional lymph node lymphocytes from lung cancer patients for the production of human IgG, IgM, and IgA. As assessed by electrofusion of the lymphocytes following their exposure to these agents with mouse myeloma cells and incubation of the fused hybridoma, a remarkable stimulatory effect was shown by LPS and particularly by LPS plus IL-4, which was substantially greater than that of either SAC I or PWM with or without various IL. Optimization studies indicated that the addition of PWM to LPS and IL-4 in the culture medium further stimulated the human antibody (Ab) production, and that the optimal formulation for stimulations of human IgG production was a culture medium containing 20 μg/ml of LPS, 1/500 of PWM, and 100 u/ml of IL-4.     

Aggression and preputial gland of male mice affected by the presence of other males

The level of aggressiveness and the weight of preputial gland and testis in male mice (Mus musculus) were influenced by housing condition, especially by the presence of cohabitant males. In this study, the relation between aggressiveness and the preputial gland and testis weight was studied for various housing conditions. The mouse individually housed in a cage that was linked to another cage containing another male separated by wire net was more aggressive than isolated or paired mice. The preputial gland weight also showed the same tendency, suggesting that the odor from other males promotes pituitary-gonadal activity in males, and that long-term cohabitance inhibits it.     

DNA polymerases and DNA topoisomerases solubilized from nuclear matrices of regenerating rat livers

DNA topoisomerase activity together with the activities of DNA polymerase were detected in a form tightly associated with rat liver nuclear matrices. DNA polymerase activities were solubilized from the nuclear matrices of regenerating rat livers by sonic treatment followed by extraction of these activities with detergent and salt. The predominant activity was mainly α-polymerase as judged from the size determined by sucrose density gradient centrifugation. However, only β-polymerase activity was detected in the matrix of normal rat livers. DNA topoisomerase activity, detected in both regenerating and normal liver nuclear matrices, showed a molecular size of about 4 S in sucrose gradient, and was active in the presence of EDTA. These results suggest that this enzyme belongs to type I topoisomerase.     

Fluorometric estimation of surface potential change associated with chemotactic stimulation in Tetrahymena pyriformis

For the quantitative estimation of surface potential change in intact cells a method was devised with the use of fluorescent probes, 8-anilino-1-naphthalenesulfonate (ANS) and N-phenyl-1-naphthylamine (NPN). Estimated values in liposomes were compared with changes in the zeta potential determined from electrophoresis. Both values agreed within the experimental variation, showing the usefulness of the method. The method was also applied to Tetrahymena pyriformis, which exhibits chemotaxis to various chemical stimuli. The surface potential change was observed when the cell was stimulated not only by inorganic salts but also by electrically neutral, hydrophobic compounds. The surface potential started to change in accordance with the depolarization of the membrane potential, except for the case of K⁺. Changes in the surface potential of T. pyriformis in response to Ca²⁺ and K⁺ were compared with those in the membrane potential. The quantitative contribution of the surface potential to cell depolarization associated with chemoreception is discussed.     

Immunological study of the regulation of cellular arylsulfatase synthesis in Klebsiella aerogenes.

Regulation of cellular arylsulfatase synthesis in Klebsiella aerogenes was analyzed by immunological techniques. Antibody directed against the purified arylsulfatase from K. aerogenes W70 was obtained from rabbits and characterized by immunoelectrophoresis, double-diffusion, quantitative precipitation, and enzyme neutralization tests. Arylsulfatase was located in the periplasmic space when the wild-type strain was cultured with methionine or with inorganic sulfate plus tyramine, but not with inorganic sulfate without tyramine, as the sole sulfur source. Tyramine oxidase was retained in the membrane fraction prepared from cells grown in the presence of tyramine. Arylsulfatase protein was not synthesized in the presence of tyramine and inorganic sulfate by mutant K611, which is deficient in tyramine oxidase (tynA). We conclude that the expression of the arylsulfatase gene (atsA) is regulated by the expression of tynA and that inorganic sulfate serves as a corepressor. In addition, strains mutated in the atsA gene were analyzed by using antibody.