Differential levels of fertility inhibition among F-like plasmids are related to the cellular concentration offinOmRNA

1992 ◽  
Vol 6 (6) ◽  
pp. 771-780 ◽  
Author(s):  
T. van Biesen ◽  
L. S. Frost
Keyword(s):  
Cellular Concentration ◽  
Fertility Inhibition

scholarly journals Haem synthesis from exogenous 5-aminolaevulinate in cultured chick-embryo hepatocytes. Effects of inducers of cytochromes P-450

1987 ◽  
Vol 248 (1) ◽  
pp. 229-236 ◽  
Author(s):  
S I Shedlofsky ◽  
P R Sinclair ◽  
H L Bonkovsky ◽  
J F Healey ◽  
A T Swim ◽  
...  
Keyword(s):  
Chick Embryo ◽  
Iron Chelator ◽  
Cellular Concentration ◽  
Haem Biosynthesis ◽  
Cytochrome P 450 ◽  
In Cells

The effects of inducers of cytochrome P-450 on haem biosynthesis from 5-aminolaevulinate were examined by using cultured chick-embryo hepatocytes. Cultures treated with either 2-propyl-2-isopropylacetamide or 3-methylcholanthrene contained increased amounts of cytochrome P-450 and haem. After treatment for 3 h with 5-amino[4-14C]laevulinate, the relative amounts of radioactivity accumulating as haem corresponded to the relative amounts of total cellular haem, but not to increases in the amounts of cytochrome P-450. Treatment with 5-aminolaevulinate did not alter cellular haem or cytochrome P-450 concentrations in either control or drug-treated cultures. The mechanism of the enhanced accumulation of radioactivity in haem was investigated. Although 2-propyl-2-isopropylacetamide enhanced the uptake of 5-aminolaevulinate and increased the cellular concentration of porphobilinogen 1.5-fold, these changes did not account for the increases in haem radioactivity. The inducing drugs had no effect on the rates of degradation of radioactive haem, but appeared to enhance conversion of protoporphyrin into haem. This latter effect was shown by: (1) a decreased accumulation of protoporphyrin from 5-aminolaevulinate in cells treated with inducers, and (2) complete prevention of this decrease if the iron chelator desferrioxamine was present. We conclude that inducers of cytochrome P-450 may increase haem synthesis not only by increasing activity of 5-aminolaevulinate synthase, but also by increasing conversion of protoporphyrin into haem.

scholarly journals Extended erythrocyte and reticulocyte parameters in the diagnosis of iron deficiency in hemodialysis patients

2020 ◽  
Vol 3 (4) ◽  
pp. 109-113
Author(s):  
Mohammed Nazim Bennaoum ◽  
◽  
Affaf Adda ◽  
Mohamed Chekkal ◽  
Fatima Seghier ◽  
...  
Keyword(s):  
Iron Deficiency ◽  
Iron Status ◽  
High Sensitivity ◽  
Hemodialysis Patients ◽  
Chronic Hemodialysis ◽  
Red Cells ◽  
Corpuscular Hemoglobin ◽  
Cellular Concentration ◽  
Stage Renal Disease ◽  
End Stage

Objective: Iron deficiency (ID) is a frequent complication in end stage renal insufficiency. These patients have to be diagnosed and treated to reduce the prevalence of anemia. Functional iron deficiency (FID) is a situation that can disrupt biochemical iron tests and mask an eventual association with ID. In this study, we tried to prove the ability of extended parameters of red cells and reticulocytes to diagnose ID without being influenced by FID. Design and methods: 164 chronic hemodialysis patients (CHP) in end stage renal disease were enrolled. Research parameters of red cells and reticulocytes determined on ADVIA 2120i were studied in the diagnosis of ID associated or not with chronic inflammation. Results: Parameters such as corpuscular hemoglobin of mature red cells (CHm), corpuscular hemoglobin of reticulocytes (CHr), cellular concentration of hemoglobin in mature red cells (CHCMm), cellular concentration of hemoglobin in reticulocytes (CHCMr) and percentage of microcytic and hypochromic red cells (HYMI) showed a high sensitivity to diagnose ID. However, the distinction of combined iron deficiency (CID) from other entities was not possible with all parameters. In chronic inflammatory states, the decrease of CHm, CHCMm and CHCMr with the rise of percentage hypochromic mature red cells (HYPOm) and reticulocytes (HYPOr) is in favor of CID. So, determination of inflammatory state is needed to complete research parameters of blood count in CHP. Conclusion: Extended erythrocyte and reticulocyte parameters can be useful to check iron status in CHP.

scholarly journals Cellular and Matrix Contributions to Tissue Construct Stiffness Increase with Cellular Concentration

2006 ◽  
Vol 35 (2) ◽  
pp. 320-320 ◽  
Author(s):  
J. Pablo Marquez ◽  
Guy M. Genin ◽  
Kenneth M. Pryse ◽  
Elliot L. Elson
Keyword(s):  
Cellular Concentration ◽  
Tissue Construct

scholarly journals Evidence that binding of CTP:phosphocholine cytidylyltransferase to membranes in rat hepatocytes is modulated by the ratio of bilayer- to non-bilayer-forming lipids

1993 ◽  
Vol 291 (2) ◽  
pp. 419-427 ◽  
Author(s):  
H Jamil ◽  
G M Hatch ◽  
D E Vance
Keyword(s):  
Phospholipase A2 ◽  
Phospholipase C ◽  
Cultured Cells ◽  
Normal Values ◽  
Common Factor ◽  
Rat Hepatocytes ◽  
Cellular Membranes ◽  
Ctp:Phosphocholine Cytidylyltransferase ◽  
Cellular Concentration

The mechanism by which phospholipase C (PLC) digestion of cultured cells mediates binding of CTP:phosphocholine cytidylyltransferase to cellular membranes was investigated. Incubation of choline-depleted rat hepatocytes with PLC caused a translocation of enzyme from cytosol to membranes concomitant with a decrease in the concentration of phosphatidylcholine with no effect on the concentration of other phospholipids. Removal of PLC and supplementation with choline restored the amount of phosphatidylcholine in the cells and translocated cytidylyltransferase to the cytosol. However, when phosphatidylcholine levels were decreased by incubation with phospholipase A2 (PLA2), there was no significant redistribution of cytidylyltransferase activity. With PLA2 the concentration of phosphatidylethanolamine, as well as of phosphatidylcholine, was significantly decreased. Since PLC, but not phospholipase A2, raised the cellular concentration of diacylglycerol, possibly diacylglycerol mediated the binding of cytidylyltransferase to membranes. This possibility was examined, but is unlikely, since addition of lysophosphatidylcholine to PLC-treated cells restored the concentration of phosphatidylcholine and released cytidylyltransferase into the cytosol, but did not lower diacylglycerol levels to normal values. Studies in vitro, incubations of cells with choline analogues and a survey of the literature suggested that the over-riding common factor in regulation of cytidylyltransferase binding to membranes may be the ratio of bilayer to non-bilayer lipids in that membrane.

Cellular concentrations of glutamine synthetase in murine organs

2006 ◽  
Vol 84 (2) ◽  
pp. 215-231 ◽  
Author(s):  
Henny W.M van Straaten ◽  
Youji He ◽  
Marjan M van Duist ◽  
Wil T Labruyère ◽  
Jacqueline L.M Vermeulen ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Epithelial Cells ◽  
Glutamine Synthetase ◽  
Posttranscriptional Regulation ◽  
Minor Importance ◽  
Activity Levels ◽  
Protein Ratio ◽  
Cellular Concentration ◽  
S3 Segment ◽  
Relative Differences

Glutamine synthetase (GS) is the only enzyme that can synthesize glutamine, but it also functions to detoxify glutamate and ammonia. Organs with high cellular concentrations of GS appear to function primarily to remove glutamate or ammonia, whereas those with a low cellular concentration appear to primarily produce glutamine. To validate this apparent dichotomy and to clarify its regulation, we determined the GS concentrations in 18 organs of the mouse. There was a >100-fold difference in GS mRNA, protein, and enzyme-activity levels among organs, whereas there was only a 20-fold difference in the GS protein:mRNA ratio, suggesting extensive transcriptional and posttranscriptional regulation. In contrast, only small differences in the GS enzyme activity : protein ratio were found, indicating that posttrans lational regulation is of minor importance. The cellular concentration of GS was determined by relating the relative differences in cellular GS concentration, detected using image analysis of immunohistochemically stained tissue sections, to the biochemical data. There was a >1000-fold difference in cellular concentrations of GS between GS-positive cells in different organs, and cellular concentrations were up to 20× higher in subpopulations of cells within organs than in whole organs. GS activity was highest in pericentral hepatocytes (~485 µmol·g–1·min–1), followed in descending order by epithelial cells in the epididymal head, Leydig cells in the testicular interstitium, epithelial cells of the uterine tube, acid-producing parietal cells in the stomach, epithelial cells of the S3 segment of the proximal convoluted tubule of the kidney, astrocytes of the central nervous tissue, and adipose tissue. GS activity in muscle amounted to only 0.4 µmol·g–1·min–1. Our findings confirmed the postulated dichotomy between cellular concentration and GS function.Key words: mRNA, protein, enzyme activity, posttranscriptional regulation, quantitative immunohistochemistry.

Steroid release from polymer vaginal devices. Effect on fertility inhibition

Steroids ◽  
1973 ◽  
Vol 21 (3) ◽  
pp. 325-333 ◽  
Author(s):  
Juan Zañartu ◽  
Rodolfo Guerrero
Keyword(s):  
Fertility Inhibition
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