Increased ketogenesis related to insulin deficiency in isolated hepatocytes from NIDDM model rats.

To investigate the hepatic ketone body metabolism in NIDDM, we studied the ketone body production rates in hepatocytes from newly developed non-obese NIDDM model rats. NIDDM model rats were prepared by intraperitoneal injection of streptozotocin at 2 or 5 days of age (STZ2, STZ5 respectively). After 10-15 weeks, ketone body production rates in hepatocytes isolated from these rats were compared with those from control rats as well as ketotic rats made by intravenous injection of streptozotocin into adult rats. Basal ketone body production rates from 0.3 mM [U-14C] palmitate in hepatocytes from control, STZ 2, STZ 5 and ketotic rats were 11.7 +/- 0.98, 14.9 +/- 0.72, 16.0 +/- 0.45, 22.8 +/- 2.32 nmole.palmitate/mg.prot/hr, respectively. These rates were stimulated by 1 microgram/ml of glucagon in control, STZ 2 and STZ 5 rats (14.1 +/- 0.99, 18.6 +/- 1.36, 18.7 +/- 0.69 nmole.palmitate/mg.prot/hr, respectively), but not in ketotic rats (22.8 +/- 2.07 nmole.palmitate/mg.prot/hr). The similar effects were observed by 1 microgram/ml of epinephrine. The basal ketone body production rates were negatively correlated to both hepatic glycogen contents and plasma IRI levels. Considering these parameters together, the extent of metabolic derangement in STZ 2 and STZ 5 rats was between that in control and ketotic rats. These results indicate that the derangements of hepatic ketone body production are related to the severity of insulin deficiency and suggest that the enhanced hepatic ketogenesis contributes in part to the elevated plasma ketone body levels in non-obese NIDDM.     

Lipopolysaccharide inhibits activation of latent transforming growth factor-β in bovine endothelial cells

The activation of latent transforming growth factor-β (TGF-β) by vascular endothelial cells (ECs) is regulated by cellular plasminogen activator (PA)/plasmin, transglutaminase (TGase), and latent TGF-β levels. Because lipopolysaccharide (LPS) has been reported to reduce EC surface plasmin levels by increasing the production of the inhibitor of PA, PA inhibitor-1 (PAI-1), we have tested whether LPS might suppress latent TGF-β activation in ECs using two different systems, namely, bovine aortic ECs (BAECs) cocultured with smooth muscle cells (SMCs) and BAECs treated with retinol. BAECs were either cocultured with SMCs after treatment with 15 ng/ml LPS or were treated with 2 μM retinol and/or 10 ng/ml LPS, and the expression of PA, surface plasmin, TGase, and the amounts of active and latent TGF-β secreted into the culture modium were measured. The downregulation of surface PA/plasmin levels with LPS was accompanied by a profound decline of both TGase and latent TGF-β expression as well as the suppression of surface activation of latent TGF-β. The effect was dependent on the concentration of LPS and on treatment time. The formation of TGF-β did not occur in cells maintained in LPS-contaminated culture medium. © 1995 Wiley-Liss, Inc.     

Mouse {beta}-galactoside {alpha}2,3-sialyltransferases: comparison of in vitro substrate specificities and tissue specific expression

Four types of ß-galactoside     

Serum thyroglobulin concentration in normal pregnancy

We measured the levels of serum thyroglobulin (Tg) in 52 pregnant females at various stages and compared them with those of 15 age-matched nonpregnant females. Serum Tg was measured by a solid-phase immunoradiometric assay. In pregnant females, mean serum Tg levels at the first, second, early third, and late third trimesters were 8.4 (range; 1.3-18.0), 9.2 (1.7-25.6), 10.1 (1.8-22.8), and 12.1 ng/ml (5.3-25.2), respectively. The statistical comparison was made after logarithmic transformation of the data. The mean value only at the late third trimester was significantly higher than that of controls (mean; 6.0 ng/ml, range; 1.5-23.6), but each value was within the normal range. Although serum Tg levels have been reported to be high at the end of pregnancy, our results indicate that the Tg levels in females could be clinically interpreted without regard to the coexistence of pregnancy.     

Biological activities of analogues of lipid A based chemically on the revised structural model. Comparison of mediator-inducing, immunomodulating and endotoxic activities

Lipid A analogues were chemically synthesized based on the model structure recently revised, and biological activities of the analogues were tested. The analogue, (beta-1,6)-linked glucosamine disaccharide carrying ester-bound 3-hydroxytetradecanoic acids at 3 and 3' position of reducing and nonreducing glucosamine in addition to amide-bound 3-hydroxytetradecanoic acids and glycosidic-linked and ester-linked phosphate groups, showed much stronger activities for mediator inducing and immunomodulating as well as endotoxic activities than those exhibited by the previously synthesized analogues based on the old model. Among the activities tested, induction of interferon and tumor necrosis factor as well as mitogenicity, adjuvanticity and pyrogenicity were, however, not expressed so strongly as natural lipid A used as controls. In contrast, the analogue exhibited comparable activities to those of control lipid A in the test of lethal toxicity to mice and gelating activity of Limulus amebocyte lysate. Other synthetic analogues carrying a phosphate group showed comparable, slightly stronger or weaker activities depending on the test, but nonphosphorylated analogue exhibited no apparent or only very weak activities.     

Detection of inactive or less active forms of tyrosine hydroxylase in human adrenals by a sandwich enzyme immunoassay

A sensitive sandwich enzyme immunoassay for tyrosine hydroxylase (TH) from bovine and human adrenals has been developed. Anti-TH antibody was prepared from bovine adrenal TH. The assay system consisted of an antibody F(ab')2 immobilized on polystyrene beads as a solid phase and of beta-D-galactosidase-conjugated antibody. This method was highly sensitive and specific for the assay of TH. Human adrenal TH level was determined by similar sensitivity as bovine adrenal TH, suggesting the presence of common antigenic sites between human and bovine adrenal enzymes. The presence of inactive or less active forms of TH in human adrenals was revealed by purification of the enzyme and monitoring with this enzyme immunoassay as well as with enzyme activity assay.     

Biological activities of chemically synthesized analogues of the nonreducing sugar moiety of lipid A

Adriamycin-Fe3+ complex catalyzes the formation of hydroxyl radical from hydrogen peroxide but the DNA-adriamycin-iron ternary complex is much more effective. 11-Deoxyadriamycin, which shows no spectral evidence of complex formation with iron, was ineffective. The generation of hydroxyl radical by adriamycin-Fe3+ complex in the presence of DNA correlates with its ability to cleave DNA. Hydroxyl radicals are thus implicated as the reactive oxygen species involved in the DNA damage caused by the adriamycin-Fe3+ complex.     

Suppression of IgE antibody production in SJL mice. II. Expression of Ly-1 antigen on helper and nonspecific suppressor T cells.

Under appropriate conditions of immunization combined with irradiation, SJL/J mice show a high and persistent anti-DNP IgE antibody response. Spleen cells transferred from normal untreated SJL mice suppress this response. Elimination of Ly-1+ cells, but not of Ly-2+ cells, abolished the capacity of spleen cells to suppress the IgE response. Thus of the three T cell Ly subclasses presently identified, Ly-1, Ly-2,3, and Ly-1,2,3, the normal SJL spleen cell which suppresses the IgE response of irradiated-immunized SJL mice belongs to the Ly-1 set. It is not known whether this Ly-1 cell suppresses the IgE response directly or by helping another cell in the recipient. The carrier-specific helper cell activity for IgE and probably IgG1 antibody response belongs to Ly-1 subclass in the SJL strain also.