| 1. |
- Alston-Smith, J, et al.
(författare)
-
Endotoxin, epinephrine, glucagon, insulin and calcium ionophore A23187 modulation of pyruvate kinase activity in cultured rat hepatocytes
- 1990
-
Ingår i: Acta chirurgica Scandinavica. - : Taylor & Francis. ; 156:10, s. 677-681, s. 677-681
-
Tidskriftsartikel (refereegranskat)abstract
- Altered glucose metabolism is one of the commonly observed sequelae of sepsis and septic shock. The present investigation was undertaken to determine the role of endotoxin (ET) upon hepatocyte glucoregulation, by measuring the activity of pyruvate kinase (PK), a key glycolytic enzyme. Hepatocytes were exposed to endotoxin concentrations known to occur in vivo during sepsis, i.e., from 1 X 10(-14) to 1 X 10(-8) g/ml. The alteration of the enzyme activities after addition of epinephrine, glucagon, insulin and calcium ionophore A23187 with and without ET preincubation were also examined. ET alone decreased the PK activity by 12% at all concentrations tested. The basal inhibition of the enzyme caused by epinephrine (-48%) was partially blocked by ET preincubation above 1 X 10(-10) g/ml. There were no ET-(glucagon, calcium ionophore, insulin) interaction. These in vitro results do not support pyruvate kinase as a site of hepatic enzyme regulation defect in endotoxaemia.
|
|
| 2. |
|
|
| 3. |
- Mehmet, Huseyin, et al.
(författare)
-
Early signals in the mitogenic response of Swiss 3T3 cells : a comparative study of purified PDGF homodimers
- 1990
-
Ingår i: Growth Factors. - : Taylor & Francis. - 0897-7194 .- 1029-2292. ; 3:2, s. 83-95
-
Tidskriftsartikel (refereegranskat)abstract
- Platelet-derived growth factor (PDGF) occurs as three dimeric isoforms, AA, BB, and AB. Two distinct receptor subunits, alpha and beta, have been identified which bind either all three isoforms of PDGF (alpha) or PDGF-BB only (beta). Here, we have compared the effect of purified PDGF homodimers on the early intracellular signaling events and mitogenesis in Swiss 3T3 cells, which possess equivalent numbers of the alpha and beta subunits. Both PDGF-AA and PDGF-BB stimulated receptor phosphorylation, inositol phosphate formation, activation of protein kinase C, calcium mobilization, EGF receptor transmodulation, sodium uptake, arachidonic acid release, cyclic AMP accumulation, and c-fos induction in a comparable, dose-dependent manner (half-maximal values for all these response were in the 2-10 ng/ml range for both homodimers). At high concentrations of PDGF (greater than 10 ng/ml), the BB homodimer effect on early membrane and cytosolic signals was 20-30% greater than PDGF-AA, reflecting the greater number of available binding sites for PDGF-BB. DNA synthesis studies indicated that PDGF-AA and PDGF-BB were potent mitogens for Swiss 3T3 cells, displaying identical dose-response effects. Moreover, the mitogenic activities of both homodimers were equally potentiated in the presence of insulin. These results indicate that both PDGF-AA and PDGF-BB stimulate the full complement of molecular responses required for the synergistic interactions mediating long-term mitogenesis. We conclude that alpha and beta receptor subunits do not differ in their ability to transduce PDGF-mediated signals leading to DNA synthesis in Swiss 3T3 cells.
|
|
| 4. |
- Möller, Claes, 1950-, et al.
(författare)
-
Otoneurological findings in workers exposed to styrene
- 1990
-
Ingår i: Scandinavian Journal of Work, Environment and Health. - : Scandinavian Journal of Work, Environment and Health. - 0355-3140 .- 1795-990X. ; 16:3, s. 189-194
-
Tidskriftsartikel (refereegranskat)abstract
- An otoneurological test battery was administered to 18 workers with long-term exposure (6-15 years) to styrene at levels well below the current Swedish limit (110 mg/m3). The results were compared with those of a reference group. Disturbances were found in the central auditory pathways of seven workers. Tests reflecting central processing of impulses from different sensory equilibrium organs were abnormal for 16 workers. The most relevant tests seemed to be static posturography and the rotatory visual suppression test. In the posturography the styrene group had a significantly larger sway area than the reference group. In the visual suppression test, the styrene workers displayed a significantly poorer ability to suppress vestibular nystagmus than the reference group. It was concluded that styrene exposure in industrial environments at moderate or low levels causes central nervous system disturbances which are not always diagnosable with psychometric tests but can be apparent in special otoneurological tests.
|
|
| 5. |
|
|
| 6. |
- Nånberg, Eewa, 1957-, et al.
(författare)
-
Fibroblast growth factor stimulates protein kinase C in quiescent 3T3 cells without Ca2+ mobilization or inositol phosphate accumulation
- 1990
-
Ingår i: Journal of Cellular Physiology. - : Wiley-Blackwell Publishing Inc.. - 0021-9541 .- 1097-4652. ; 143:2, s. 232-242
-
Tidskriftsartikel (refereegranskat)abstract
- To elucidate the transmembrane signalling processes initiated by fibroblast growth factor (FGF), we have studied the effect of recombinant basic FGF (bFGF) on various early events associated with mitogenesis in Swiss 3T3 fibroblasts. bFGF, at mitogenic concentrations, neither induced Ca2+ mobilization from intracellular stores nor increased the accumulation of inositol phosphates. In contrast, bFGF stimulated the phosphorylation of the Mr 80,000 (80K) cellular protein which is a major substrate of protein kinase C. This effect was potentiated by the diacylglycerol kinase inhibitor R59022. Two-dimensional polyacrylamide gel electrophoresis and phosphopeptide mapping showed that the 80K phosphoproteins generated in response to bFGF, bombesin, and phorbol 12,13-dibutyrate were indistinguishable. Down-regulation of protein kinase C prevented bFGF stimulation of 80K phosphorylation. Other protein kinase C-dependent early events such as transmodulation of the epidermal growth factor receptor, cytoplasmic alkalinization, inhibition of vasopressin induced increase in cytosolic [Ca2+], and enhancement of cAMP accumulation in response to forskolin were also induced by bFGF. Similar results were obtained when bFGF was added to quiescent cultures of tertiary mouse embryo fibroblasts. We conclude that bFGF stimulates protein kinase C through a signal transduction pathway distinct from inositol phospholipid turnover and Ca2+ mobilization.
|
|
| 7. |
|
|
| 8. |
- Akner, Gunnar, 1953-, et al.
(författare)
-
Immunocytochemical localization of glucocorticoid receptor in human gingival fibroblasts and evidence for a colocalization of glucocorticoid receptor with cytoplasmic microtubules
- 1990
-
Ingår i: European Journal of Cell Biology. - 0171-9335 .- 1618-1298. ; 53:2, s. 390-401
-
Tidskriftsartikel (refereegranskat)abstract
- The cellular distribution of the glucocorticoid receptor (GR) in relation to various intracellular and plasma membrane structures in human fibroblasts was studied using indirect immunofluorescence techniques with monoclonal and polyclonal antibodies. During interphase, GR was located predominantly in the cytoplasm, showing a similar pattern as tubulin. In mitotic cells, GR and tubulin were localized in mitotic spindles and in telophase midbodies. Colchicine and vinblastine induced a similar redistribution of GR and tubulin to the cell periphery. This redistribution was reversible for colchicine but not for vinblastine. Vinblastine also induced paracrystals containing GR and tubulin. These results support the hypothesis that GR interacts in vivo with cytoplasmic microtubules.
|
|
| 9. |
|
|
| 10. |
|
|
