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Biomedical subjects

J E Tanner

Publications and source records attributed to J E Tanner.

28 records · Page 2Linked to original sources
PubMed1992

Regulation of B-cell growth and immunoglobulin gene transcription by interleukin-6.

Interleukin-6 (IL-6) stimulates growth and immunoglobulin (lg) secretion in Epstein-Barr virus (EBV)-infected B cells. In this study, we demonstrate that B-cell activation by IL-6 is associated with an initial induction of c-myc, a gene believed to act as a competence factor for increased RNA transcription and DNA replication, and by increases in DNA, RNA, and protein synthesis, as well as cell number. IL-6 increased the levels of lg mRNA per cell in comparison to a non-cycle-dependent cellular mRNA, tubulin. However, two other cell cycle-dependent cellular mRNAs, c-myc and actin, were also induced by IL-6 comparable to lg mRNAs. Increased levels of lg mRNA were not due to significant changes in RNA turnover, but appeared to reflect increased levels of RNA transcription. Together, these findings support the notion that IL-6 plays an important role as a stimulator of DNA and RNA synthesis in EBV-activated B cells.

Actins↗
PubMed1992

Inefficient bacteriolysis of Escherichia coli by serum from human neonates.

To assess bacteriolysis in human neonates, Escherichia coli O7w:K1:NM were incubated with sera from eight healthy neonates, serum pooled from the eight neonates, and serum pooled from healthy adults. The adult serum killed E. coli. In contrast, the bacteria were not killed during incubation with sera from the eight neonates, the pooled neonatal serum, or with heat-inactivated adult serum. However, the combination of pooled neonatal serum and heat-inactivated adult serum killed the bacteria. Supplemental IgG-containing antibodies that bound to E. coli did not enhance the bactericidal activity of the neonatal serum. Ten of 12 blood isolates of E. coli from septic neonates but only 8 of 15 isolates from septic adults were serum-sensitive (killed during incubation with adult serum) (P less than .05). Therefore, neonatal serum killed E. coli inefficiently and was deficient in non-IgG heat-stabile component(s) required for bacterial killing. Compared with adults, neonates were more frequently septic with serum-sensitive strains of E. coli.

Adult↗
PubMed1992

Complement factor 9 deficiency in serum of human neonates.

The serum concentration of complement factor C9 (C9) was 260 +/- 47 micrograms/ml (+/- SE) in 14 mothers and less than 42 micrograms/ml in each of their 14 neonates. During incubation for 60 min, 11 of 14 maternal sera and 3 of 14 neonatal sera reduced the survival of Escherichia coli O7w:K1:NM to less than 20% of the original inoculum (P less than .03). Eleven neonatal sera did not kill the bacteria. Supplemental C9 (60 micrograms/ml) enhanced the bactericidal capacity of 10 neonatal sera. 125I-labeled C9 was deposited onto E. coli by neonatal sera, but less efficiently than by pooled adult sera. Supplemental IgG enhanced 125I-labeled C9 deposition and potentiated the bactericidal activity of exogenous C9. Therefore, neonatal sera contained diminished concentrations of C9 and killed E. coli inefficiently. In neonatal sera, supplemental C9 was deposited onto E. coli and enhanced bactericidal activity. These effects of C9 were potentiated by supplemental IgG.

Adult↗
PubMed1991

Diminished IgG, but not complement C3 or C4 or factor B, precedes nosocomial bacterial sepsis in very low birth weight neonates.

The significance of low serum IgG and complement proteins in very low birth weight (VLBW; less than 1500 g) neonates is not known. Therefore serum IgG, C3, C4 and Factor B were quantitated weekly by rate nephelometry in 15 VLBW neonates who developed proven nosocomial bacterial or candidal sepsis (Group A) and 27 VLBW neonates who did not develop sepsis (Group B). In the first week of life the serum IgG of neonates in Group A was 295 +/- 33 mg/dl (mean +/- SEM) and in Group B it was 440 +/- 21 mg/dl (P less than 0.01). In the second week, the IgG of Group A was 270 +/- 32 mg/dl and that of Group B was 473 +/- 38 mg/dl (P less than 0.01). If the IgG was less than 350 mg/dl in the first week or less than 230 mg/dl in the second week, the relative risk of acquiring sepsis was greater than or equal to 5 (95% confidence interval in the first week, 1.7 to 11.2). The serum IgG was measured before the onset of sepsis in 14 of the 15 neonates in Group A. In the week before sepsis the IgG of the 14 neonates was less than 440 mg/dl (range, 45 to 433 mg/dl) in all cases, was below the mean IgG of Group B in 12 of 14 cases (P = 0.006 vs. Group B) and was greater than 2 SD below the mean IgG of Group B in 4 of 14 cases (P = 0.0003 vs. Group B).(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Infections↗
PubMed1990

Biochemical and biological analysis of human interleukin 6 expressed in rodent and primate cells.

The cDNA for human interleukin 6 (IL 6) was stably expressed at high levels in the three mammalian cell lines COS-7, PA317, and GH3 to yield IL 6 proteins of 25 to 27, 26, 22 to 24, and 23 kDa molecular mass. Both size and relative amounts of the recombinant IL 6 (rIL 6) species produced correspond to those of natural IL 6 secreted by LPS-stimulated monocytes. Oligosaccharide analysis of recombinant IL 6 utilizing tunicamycin and endoglycosidases revealed O- and N-linked glycosylation that is comparable to that of natural IL 6 derived from human monocytes and fibroblasts. IL 6 expressed in each of the three cell lines was phosphorylated similarly to the IL 6 produced in human monocytes and fibroblasts. IL 6 secreted by the three different cell lines have marked differences in specific biological activities. COS-7 IL 6 appeared to be 12-fold more active in its hybridoma growth factor activity than that made in PA317 or GH3 cells. In contrast, PA317 and GH3 IL 6 were 230 and 6.7 times more effective than COS-7 IL 6 in inducing Ig production in CESS cells. Also, PA317 and GH3 IL 6 were more effective than COS-7 IL 6 in inducing the acute-phase protein fibrinogen in human hepatocytes. The rIL 6 species exhibited no antiviral activity.

Acute-Phase Proteins↗
PubMed1983

Intracellular diffusion of water.

Self-diffusion of cell water has been measured at diffusion times ranging from 0.3 ms to 1.0 s for human red cells, yeast, and brine shrimp using various pulsed gradient NMR methods. Intracellular diffusion coefficients and membrane permeabilities are calculated from these data with the aid of previous theoretical results for regularly spaced permeable planar barriers. The intracellular diffusion coefficients of water range from 1.2 X 10(-6) to 6 X 10(-6) cm2/s for the various samples. Outer-membrane permeabilities to water range from 0.0001 to 0.01 cm/s. The self-diffusion coefficient of lipid in a sample of human breast adipose tissue was found to be 1.5 X 10(-7) cm2/s.

Adipose Tissue↗
PubMed1979

Self diffusion of water in frog muscle.

Self diffusion of cell water has been measured at diffusion times ranging form 0.3 ms to 2.4 s for three muscle types of Rana pipiens, using various magnetic field gradient nuclear magnetic resonance methods. Intracellular diffusion coefficients and membrane permeabilities are calculated with the aid of previous theoretical results for regularly spaced permeable planar barriers. The intracellular diffusion coefficient is 1.6 x 10-5 cm2/s, in approximate agreement with other literature values for skeletal muscles. The outer membrane permeabilities are estimated at 0.01 cm/s for two of the muscle types, and much higher for the other one.

Animals↗