Pattern and kinetics of cytokine production following administration of phosphorothioate oligonucleotides in mice.

Phosphorothioate oligonucleotides with certain sequences or structure motifs can stimulate the immune system. We administered to mice a 27-mer phosphorothioate oligonucleotide (sequence 5'-TCG TCG CTG TCT CCG CTT CTT CTT GCC-3'), which has previously been shown to cause splenomegaly and hypergamma-globulinemia on in vivo administration in mice, and studied the pattern and kinetics of cytokine production at both the splenic mRNA and serum protein levels. Following i.p. administration of 50 mg/kg of oligonucleotide, significant increases in the splenic mRNA levels of IL-6, IL-12p40, IL-1 beta, and IL-1Ra and serum levels of IL-6, IL-12, MIP-1 beta, and MCP-1 were observed. In contrast, no significant differences in splenic mRNA levels of IL-2, IL-4, IL-5, IL-9, IL-13, IL-15, IFN-gamma, or MIF or serum levels of IL-2, IL-4, IL-5, IL-10, IFN-gamma, or GM-CSF were detected. The induction of IL-12 secretion was dependent on the sequence and dose of the oligonucleotides. One oligonucleotide (sequence 5'-GAG AAC GCT CGA CCT TCG AT-3') induced a high level of IL-12 secretion even at 5 mg/kg, whereas another oligonucleotide (sequence 5'-CTC TGC CAC CCA TCT CTC TCC TTC T-3') did not induce significant IL-12 secretion even at 50 mg/kg. IL-12 secretion induced by various doses of oligonucleotide has the same kinetics but differs in magnitude. These studies show a distinct pattern and kinetics of cytokine production following oligonucleotide administration and further demonstrate that cytokine induction is not a general property of phosphorothioate oligonucleotides but is dependent on the sequence and dose of the oligonucleotides.

An experimental study on membrane malignant phenotype of tumour cells and their reversion.

A human promyelocytic leukemic cell line (HL-60 cells) was induced to differentiate along the myeloid pathway in vitro by 1.25% dimethylsulfoxide (DMSO) as an inducer. The membrane fluidity, the quantity of ConA binding sites on the cell membrane surface, and the protein tyrosine kinase (Tyr-PK) activity existing in NP-40 membrane extract and cytoplasma extract were determined respectively. The activity of tumour-derived immunosuppressive factor (TDSF) secreted by HL-60 cells into culture supernatant was also determined. The results demonstrated that: (1) HL-60 cells were capable of undergoing differentiation onto the myeloid pathway in the presence of DMSO. The growth of DMSO-treated HL-60 cells became slow and synthesis rate of DNA decreased by about 50%. (2) Both membrane fluidity and the quantity of ConA binding sites on membrane were obviously lower after induced with DMSO than those before induction. (3) The Tyr-PK activity in the NP-40 membrane extract increased during the period of induced differentiation. The phosphorylation level of endogenous protein in cytoplasma extract decreased with the process of induced differentiation. It may be reasoned that the phosphatase activity is much higher than the phosphorylase activity. (4) The secretive level of TDSF by HL-60 cells during the period of induced differentiation revealed no change. The preliminary results showed that the malignant phenotypes of tumour cells we used may undergo reversible changes with induced differentiation of tumour cells except the secretion of TDSF.

Experimental study of free periosteal autograft. II. Increasing osteogenesis of periosteum.

The difference in osteogenesis of the periosteal graft and the effects of changing the recipient environment were studied in 26 young and 16 adult rabbits. The periosteal grafts from bilateral tibiae were implanted to the right and left sides of the abdominal wall, on the right side a coagulum was added. For quantitative examination, radionuclide, CT, ion-selective electrode, atomic absorption spectrometry and biochemical autoassay methods were used. The results showed that osteogenesis of periosteal grafts may increase by changing the local environments. The amount of periosteal bone formed in the adult rabbits was obviously less than in the young. The bone formation of the periosteal grafts with a coagulum, especially in the adults was increased. The possible mechanism of increasing periosteal osteogenesis by the coagulum is discussed.

Experimental study of free periosteal autograft. Animals age and periosteal osteogenesis.

This is a study of the correlation between the age of animals and the osteogenic potential of free periosteal autograft. The tibial periosteum of 27 rabbits, ranging in age from 4-104 weeks, was stripped and implanted into the quadriceps. Radiographic and histologic examination demonstrated that new bone was formed in both the young and adult rabbits. The morphologic basis and mechanism of bone formation of periosteum are discussed. Maintenance of integrity of the cambium layer of the periosteal graft is emphasized. Free periosteal graft of adult rabbits in the "resting" state can retain its osteogenic potential and produce new bone.

[Measurement of molecular weight of dextran by low angle laser light scattering photometer].

The molecular weight of two dextran standards imported from Sweden of known molecular weight and one batch of Chinese made dextran 70 were determined by low angle laser scattering photometer. The resulting values of the standards were in good agreement with the labelled values. The determined results of samples were high in precision (r = 0.95). Calculated results of the least square method were approximately the same as those of the plotting method. LALLS conditions: Solvent: pure water (n25D = 1.3314); filter: 0.22 microns VG(Millipore Corp.): Annulus = 6 degrees-7 degrees; field stop: 0.2; T = 25 degrees C.