Adaptive Control at Low Glucose Concentration of HEK-293 Cell Serum-Free Cultures

1999 ◽  
Vol 15 (4) ◽  
pp. 608-616 ◽  
Author(s):  
P. Siegwart ◽  
J. Cote ◽  
K. Male ◽  
J.H.T. Luong ◽  
M. Perrier ◽  
...  
2014 ◽  
Vol 99 (6) ◽  
pp. 729-733 ◽  
Author(s):  
Tasiopoulos Konstantinos ◽  
Komnos Apostolos ◽  
Paraforos Georgios ◽  
Tepetes Konstantinos

Abstract Studies on surgical patients provide some evidence of prompt detection of enteric ischemia with microdialysis. The purpose of the study was to measure intraperitoneal microdialysis values (glucose, glycerol, pyruvate, and lactate) in patients hospitalized in an intensive care unit (ICU) with an underlying abdominal surgical condition and to correlate these values with patients' outcomes. Twenty-one patients, 10 female, were enrolled in the study. The intraperitoneal metabolite values were measured for 3 consecutive days, starting from the first day of ICU hospitalization. Descriptive and inferential statistics were performed. The t-test, repeated measures analysis, Holm's test, and a logistic regression model were applied. Level of statistical significance was set at P = 0.05. Mean age of participants was 68.10 ± 8.02 years old. Survivors exhibited statistically significantly higher glucose values on day 3 (6.61 ± 2.01 against 3.67 ± 1.62; P = 0.002). Mean lactate/ pyruvate (L/P) values were above 20 (35.35 ± 27.11). All non-survivors had a mean three day L/P values greater than 25.94. Low L/P values were related to increased survival possibilities. High microdialysis glucose concentration, high L/P ratio and low glucose concentration were the major findings during the first three ICU hospitalization days in non-survivors. Intraperitoneal microdialysis may serve as a useful tool in understanding enteric ischemia pathophysiology.


1979 ◽  
Vol 236 (3) ◽  
pp. E229 ◽  
Author(s):  
J S Kerr ◽  
N J Baker ◽  
D J Bassett ◽  
A B Fisher

We investigated the relationship between perfusate concentration of glucose and its utilization and lactate production derived from exogenous glucose and from metabolism of endogenous substrates. Isolated rat lungs were ventilated with 5% CO2 in air and perfused for 100 min with Krebs-Ringer bicarbonate buffer containing 3% bovine serum albumin, 10(-2) U/ml insulin, [U-14C]glucose and [5-3H]glucose. Glucose utilization, total lactate production, [14C]lactate production, and 3H2O production were measured. The apparent Km and Vmax for glucose utilization were 3.4 mM and 72.5 mumol/g dry wt per h, respectively. Lactate production from endogenous substrates, calculated as the difference between total and [14C]lactate, was 37.6 +/- 2.2 mumol/g dry wt (n = 36); it was unaffected by perfusate glucose concentration and by omission of insulin, but increased threefold with anoxia. Lactate production from 1.5 mM glucose was significantly less (P less than 0.02) with insulin omitted. Glycogen content was unchanged during perfusion without glucose. These results suggest that: 1) protein catabolism contributes to lung lactate production; 2) glucose utilization by lung is not maximal at resting physiological glucose concentrations; and 3) insulin is required at low glucose concentrations for maximal glycolytic rates.


2003 ◽  
Vol 285 (6) ◽  
pp. R1453-R1460 ◽  
Author(s):  
S. D. Appleton ◽  
G. E. Lash ◽  
G. S. Marks ◽  
K. Nakatsu ◽  
J. F. Brien ◽  
...  

Although hypoxia induces heme oxygenase (HO)-1 mRNA and protein expression in many cell types, recent studies in our laboratory using human placental tissue have shown that a preexposure to hypoxia does not affect subsequent HO enzymatic activity for optimized assay conditions (20% O2; 0.5 mM NADPH; 25 μM methemalbumin) or HO-1 protein content. One of the consequences of impaired blood flow is glucose deprivation, which has been shown to be an inducer of HO-1 expression in HepG2 hepatoma cells. The objective of the present study was to test the effects of a 24-h preexposure to glucose-deprived medium, in 0.5 or 20% O2, on HO protein content and enzymatic activity in isolated chorionic villi and immortalized HTR-8/SVneo first-trimester trophoblast cells. HO protein content was determined by Western blot analysis, and microsomal HO enzymatic activity was measured by assessment of the rate of CO formation. HO enzymatic activity was increased ( P < 0.05) in both placental models after 24-h preexposure to glucose-deficient medium in 0.5 or 20% O2. Preexposure (24 h) in a combination of low O2 and low glucose concentrations decreased the protein content of the HO-1 isoform by 59.6% ( P < 0.05), whereas preexposure (24 h) to low glucose concentration alone increased HO-2 content by 28.2% in chorionic villi explants ( P < 0.05). In this preparation, HO enzymatic activity correlated with HO-2 protein content ( r = 0.825). However, there was no correlation between HO-2 protein content and HO enzymatic activity in HTR-8/SVneo trophoblast cells preexposed to 0.5% O2 and low glucose concentration for 24 h. These findings indicate that the regulation of HO expression in the human placenta is a complex process that depends, at least in part, on local glucose and oxygen concentrations.


2007 ◽  
Vol 41 (1-2) ◽  
pp. 133-140 ◽  
Author(s):  
Xiangzong Han ◽  
Lei Sun ◽  
Qiangyi Fang ◽  
Dongxiao Li ◽  
Xianghui Gong ◽  
...  

1979 ◽  
Vol 178 (1) ◽  
pp. 97-101 ◽  
Author(s):  
I S Hunter ◽  
H L Kornberg

Dilute cultures of wild-type Escherichia coli K12 and of derivatives impaired in one or other Enzyme-II component of the glucose phosphotransferase system were grown in continuous culture under glucose limitation. Cells harvested from the chemostat took up [U-14C]glucose from 0.1 mM solutions at rates directly related to the rates at which those cells had grown; the activity of the phosphotransferase system in those cells, rendered permeable with optimal accounts of toluene, parallels the ability of the cells to take up glucose. The capacity of these systems was rate-limiting for growth under the negligibly low glucose concentration in the chemostat, but was adequate to account for the stimulation of respiration observed when the cells were presented suddenly with excess glucose.


2017 ◽  
Vol 20 (3&4) ◽  
pp. 361-372
Author(s):  
B. Suraraksa ◽  
A. Nopharatana ◽  
P. Chaiprasert ◽  
S. Bhumiratana ◽  
M. Tanticharoen

To elucidate the effect of substrate concentration on biofilm development, glucose concentrations of 500 and 1,000 mg/L were used.  At an early stage, biofilm development at both concentrations was not significantly different (P=0.621).  After removing suspended biomass at 24 operational hours, the biofilm development at high substrate concentration was higher than at lower concentration.  At 72 operational hours, the amounts of attached biomass at low and high glucose feeding were 9.04±1.17 and 28.58±2.72 g VSS/m2, respectively.  The activities of acidogens, acetogens, and methanogens at the low glucose concentration were 0.334, 0.016 and 0.003 g COD/g VSS/h, and those at the high glucose concentration were 0.145, 0.003 and 0.001 g COD/g VSS/h, respectively.  Moreover, the ratio of methanogenic activity at low glucose concentration was higher than at high glucose concentration.  The glucose utilization at low and high feeding concentrations was 33% and 27%, respectively.  These results indicated that rapid biofilm development by using high substrate concentration would be less beneficial if unbalance of methanogenic ratio was found in biofilm.


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