Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “HEXOSES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources
PubMed1993

Impairment of chemoattractant-stimulated hexose uptake in neonatal neutrophils.

Neonatal neutrophils (polymorphonuclear leukocytes [PMN]) exhibit a well-documented deficiency in chemotaxis, the nature of which has not been fully elucidated. To determine whether impaired ability of neonatal PMN to increase hexose uptake in response to chemoattractants could contribute to this defect, we compared uptake of 2-deoxy-D-glucose (2-DOG) in stimulated versus resting PMN from neonates (cord blood) and healthy adults. Compared with unstimulated values; N-formyl-methionyl-leucyl-phenylalanine (fMLP) (optimal at 10 nmol/L) caused a threefold to fourfold increase in 2-DOG uptake by adult PMN. Unstimulated 2-DOG uptake by neonatal PMN was slightly higher than that for adult cells, but fMLP caused only a minimal (less than twofold) increase, and optimally stimulated uptake was significantly lower than for adult PMN (P < .01 for adult versus neonatal stimulated uptake; n = 6). Findings were similar when ionomycin or C5a was used as a stimulus. Optimal fMLP stimulation of adult PMN was associated with a marked decrease in the Km for 2-DOG uptake, from 0.74 +/- 0.11 to 0.23 +/- 0.03 mmol/L (delta Km = -0.51 +/- 0.12 mmol/L; n = 6). In contrast, there was relatively little fMLP-induced change in the Km for uptake of 2-DOG by neonatal PMN (from 0.44 +/- 0.04 mmol/L to 0.32 +/- 0.019 mmol/L n = 6); delta Km = -0.12 +/- 0.04 mmol/L; P = .011 for adult versus neonatal delta Km. Stimulation with fMLP was not accompanied by a significant change in the Vmax for 2-DOG uptake with either adult or neonatal PMN, and the respective values for Vmax were similar. We conclude that the chemoattractant-induced increase in hexose uptake by PMN is deficient in neonates compared with adults and that this deficiency involves mechanisms that determine the Km for this process. This impairment may contribute to defective chemotaxis in neonatal PMN.

Adult↗
PubMed1997

Glucose dependence of glycolysis, hexose monophosphate shunt activity, energy status, and the polyol pathway in retinas isolated from normal (nondiabetic) rats.

PURPOSE: To measure glucose-dependent metabolic activities and selected parameters of the polyol pathway in retinas isolated from normal rats to test the hypothesis recently proposed by Van den Enden et al that incubation of whole retinas for 2 hours with elevated concentrations of glucose results in activation of the polyol pathway, which is the cause of a redox imbalance, as measured by an increase in the retinal cytosolic lactate-pyruvate ratio and a diabetic-like state. METHODS: Retinas obtained from nondiabetic rats and separated from other ocular tissues were incubated for several hours in incubation medium containing glucose at concentrations ranging from 5 to 30 mM. Measurements were made under aerobic and anaerobic conditions of lactic acid production, retinal adenosine triphosphate (ATP), lactic acid content, the hexose monophosphate shunt pathway, aldose reductase activity, and levels of sorbitol and galactitol. Morphology was examined by light microscopy at the end of the incubations. RESULTS: Incubation of isolated rat retinas with 20 mM glucose increased lactic acid production by approximately 25% in comparison to the rate observed in 5mM glucose under aerobic and anaerobic conditions. The content of ATP and lactate in the retinas after a 2-hour incubation in the presence of oxygen and 20 mM glucose was equal to the amounts found in fresh tissues, whereas these metabolites declined, respectively, by 25% and 45% when 5 mM glucose was used. The activity of the hexose monophosphate shunt pathway in isolated rat retinas was not increased increased significantly when the concentration of glucose was raised from 5 to 30 mM. Aldose reductase activity and polyols were below our limits of detection, 0.5 nmol/minute.mg protein and 3.5 nmol/retina, respectively, under all conditions tested. The morphologic appearance of the retina was similar in the presence of normal and high concentrations of glucose. CONCLUSIONS: These results show that incubation of isolated rat retinas, obtained from nondiabetic rats, with elevated concentrations of glucose for 2 hours leads to increases in glycolysis and a higher tissue content of lactic acid and ATP in comparison to values obtained with 5 mM glucose. However, the magnitude of the glucose-dependent increase in the retinal level of lactate in the current study and in that of Van den Enden et al is six to seven times greater than the calculated flux of glucose through the polyol pathway. These results, therefore, do not support the hypothesis of Van den Enden et al. Rather, it is suggested that supranormal concentrations of glucose yield more lactate and ATP in a whole retina because they optimize the supply of this essential nutrient to cells throughout the tissue by overcoming diffusional limitations that result when the retina is separated from its normal choroidal and intraretinal blood supplies.

Adenosine Triphosphate↗
PubMed2004

From D-glucose to biologically potent L-hexose derivatives: synthesis of alpha-L-iduronidase fluorogenic detector and the disaccharide moieties of bleomycin A2 and heparan sulfate.

A novel and convenient route for the synthesis of biologically potent and rare L-hexose derivatives from D-glucose is described. Conversion of diacetone-alpha-D-glucose (14) into 1,2:3,5-di-O-isopropylidene-beta-L-idofuranose (19) was efficiently carried out in two steps. Orthogonal isopropylidene rearrangement of compound 19 led to 1,2:5,6-di-O-isopropylidene-beta-L-idofuranose (27), which underwent regioselective epimerization at the C3 position to give the L-talo- and 3-functionalized L-idofuranosyl derivatives. Hydrolysis of compound 19 under acidic conditions furnished 1,6-anhydro-beta-L-idopyranose (35) in excellent yield, which was successfully transformed into the corresponding L-allo, L-altro, L-gulo, and L-ido derivatives via regioselective benzylation, benzoylation, triflation and nucleophilic substitution as the key steps. Applications of these 1,6-anhydro-beta-L-hexopyranoses as valuable building blocks to the syntheses of 4-methylcoumarin-7-yl-alpha-L-iduronic acid and the disaccharide moieties of bleomycin A(2) as well as heparan sulfate are highlighted.

Bleomycin↗
PubMed2002

Structural characterization of hexoses and pentoses using lead cationization. An electrospray ionization and tandem mass spectrometric study.

The analytical potential of the complexation of isomeric underivatized hexoses (D-glucose, D-galactose, D-mannose, D-talose, D-fructose), methylglycosides (1-O-methyl-alpha-D-glucose and 1-O-methyl-beta-D-glucose) and pentoses (D-ribose, D-xylose, D-arabinose and D-lyxose) by Pb(2+) ions, was investigated by electrospray ionization and tandem mass spectrometry (MS/MS). Pb(2+) ions react mainly with monosaccharides by proton abstraction to generate [Pb(monosaccharide)(m) - H](+) ions (m = 1-3). At low cone voltage, a less abundant series of doubly charged ions of general formula [Pb(monosaccharide)(n)](2+) is also observed. The maximum number n of monosaccharides surrounding a single Pb(2+) ion depends on the metal : monosaccharide ratio. Our study shows that MS/MS experiments have to be performed to differentiate Pb(2+)-coordinated monosaccharides. Upon collision, [Pb(monosaccharide) - H](+) species mainly dissociate according to cross-ring cleavages, leading to the elimination of C(n)H(2n)O(n) neutrals. The various fragmentation processes observed allow the C(1), C(2) and C(4) stereocenters of aldohexoses to be characterized, and also a clear distinction aldoses and fructose. Furthermore, careful analysis of tandem mass spectra also leads to successful aldopentose distinction. Lead cationization combined with MS/MS therefore appears particularly useful to identify underivatized monosaccharides.

Cations, Divalent↗
PubMed2002

Direct stereochemical assignment of hexose and pentose residues in flavonoid O-glycosides by fast atom bombardment and electrospray ionization mass spectrometry.

Mass spectrometric methods have been developed which allow the direct stereochemical assignment of terminal monosaccharide residues in flavonoid O-glycosides without the need for chemical hydrolysis. Standards containing a glucose, galactose, mannose, xylose, arabinose or apiose residue were examined because these monosaccharides are by far the most commonly encountered in flavonoid glycosides. Following acetylation, the major peracetylated sugar related fragments, generated by fast atom bombardment (FAB) or electrospray ionization (ESI), were selected for collisional activation employing a broad range of collision energies. Both FAB and ESI proved to be useful as ionization techniques. Stereoselective fragmentation was achieved and allowed us clearly to differentiate and characterize isomeric monosaccharide residues. The method developed was successfully applied to an unknown flavonoid containing a terminal pentose and hexose residue which was isolated from Farsetia aegyptia.

Flavonoids↗
PubMed1978

Resistance of the intact and reconstituted adipocyte hexose transport system to irreversible inhibition by sulfhydryl and amino reagents.

Sensitivity of the adipocyte D-glucose transport system in intact plasma membranes or following solubilization and reconstruction into phospholipid vesicles to several protein-modifying reagents was investigated. When intact plasma membranes were incubated with N-ethylmaleimide (20 mM) or fluorodinitrobenzene (4 mM), D-glucose transport activity was virtually abolished. However, washing the membranes free of unreacted reagents restored transport activity, indicating that covalent interaction with the membrane did not mediate the transport inhibition. Reaction of [3H]N-ethylmaleimide with plasma membranes under similar conditions resulted in extensive labeling of all protein fractions resolved on dodecyl sulfate gels. Similarly, addition of N-ethylmaleimide to cholate-solubilized membrane protein had no effect on transport activity in artificial phospholipid vesicles reconstituted under conditions where the membrane protein was free of unreacted N-ethylmaleimide. Transport activity in plasma membranes was also inhibited by both reduced and oxidized dithiothreitol or glutathione (15 mM) in a readily reversible manner. consistent with a noncovalent mode of inhibition. Thus, the insulin-responsive adipocyte D-glucose transport system differs from the red cell hexose transport system in its remarkable insensitivity to modulation by covalent blockade of sulfhydryal or amino groups by the reagents studied.

Adipose Tissue↗
PubMed1979

Endogenous cyclic AMP does not modulate transport of hexoses, nucleosides, or nucleobases in Chinese hamster ovary cells.

In a previous study we have demonstrated that neither extracellular nor intracellular cyclic adenosine monophosphate (AMP) levels directly affect the uptake of nucleosides, nucleobases, or hexoses by various types of cultured mammalian cells. Uptake of these nutrients into cells, however, involves two processes operating in tandem: facilitated transport across the membrane and intracellular phosphorylation; and uptake rates generally reflect the rates of substrate phosphorylation rather than of transport. In the present study we have examined the question of whether substrate transport per se is regulated by intracellular cyclic AMP. Initially various cell lines, grown both in suspension and monolayer culture, were screened for their cyclic AMP response to prostaglandin E1, isoproterenol, and inhibitors of cyclic AMP phosphodiesterase. Prostaglandin E1 treatment of Chinese hamster ovary cells was selected as the system giving the largest and most consistent (50-fold to 100-fold) elevation of cyclic AMP. Rapid kinetic techniques were used to measure the transport of 3-O-methylglucose, thymidine, adenosine, hypoxanthine, and adenine in wild-type cells and in mutant sublines incapable of phosphorylating these substrates. In no case was an increase in intracellular cyclic AMP accompanied by a significant change in the rate of transport of these substrates, although prostaglandin E1 slightly inhibited the transport of various substrates.

Animals↗
PubMed2006

Hexose-specificity of hexokinase and ADP-dependence of pyruvate kinase play important roles in the control of monosaccharide utilization in freshly diluted boar spermatozoa.

Incubation of boar sperm from fresh ejaculates in a minimal medium with 10 mM glucose induced a fast and intense activation of glycolysis, as indicated by the observed increases in the intracellular levels of glucose 6-phosphate (G 6-P) and ATP and the rate of formation of extracellular L-lactate. The effect of glucose was much more intense than that induced by fructose, sorbitol, and mannose. The greater utilization of glucose was related to a much greater sensitivity to hexokinase when compared with the other monosaccharides. Thus, the presence of 0.5 mM glucose induced total hexokinase activity in supernatants from sperm extracts of 1.7 +/- 0.1 mIU/mg protein, while the same concentration of both fructose, mannose, and sorbitol induced total hexokinase activity from 0.3 +/- 0.1 mIU/mg protein to 0.60 +/- 1 mIU/mg protein. Kinetic analysis of the total pyruvate kinase activity indicated that this activity was greatly dependent on the presence of ADP and also showed a great affinity for PEP, with an estimated Km in supernatants of 0.15-0.20 mM. Immunological location of proteins closely related to glycolysis, like GLUT-3 hexose transporter and hexokinase-I, indicated that these proteins showed the trend to be distributed around or in the cellular membranes of both head and midpiece in a grouped manner. We conclude that glycolysis is regulated by both the specific availability of a concrete sugar and the internal equilibrium between ATP and ADP levels. Furthermore, localization of proteins involved in the control of monosaccharide uptake and phosphorylation suggests that glycolysis starts at concrete points in the boar-sperm surface.

Adenosine Diphosphate↗
PubMed1996

Hexose recognition by insulin-secreting BRIN-BD11 cells.

Clonal BRIN-BD11 cells were produced by electrofusion of NEDH rat islet B-cells with immortal RINm5F cells. Western blotting analysis revealed that unlike RINm5F, novel BRIN-BD11 cells expressed high levels of the glucose transport protein GLUT-2, coupled with a rapid and sustained uptake of D-glucose, significantly greater than RINm5F after only 5 min (p < 0.05). Whereas BRIN-BD11 cells expressed a high glucokinase:hexokinase ratio with 1.4-2.0 fold and 1.4-1.7 fold stepwise stimulation of insulin secretion with 4.2-16.7 mM D-glucose and D-mannose respectively, RINm5F had a lower glucokinase:hexokinase ratio (p < 0.001) and were notably unresponsive to D-glucose and D-mannose. Unlike RINm5F cells, BRIN-BD11 were unresponsive to other hexoses, with RINm5F only responding to D-galactose (p < 0.05). BRIN-BD11 cells should be useful for studies of nutrient-induced insulin secretion.

Animals↗
PubMed1980

Insulin binding and hexose transport in rat adipocytes. Relation to cell size.

Insulin binding, initial velocity of [14C]methylglucose transport, uptake of [14C]deoxyglucose and conversion of [U-14C]glucose to CO2, glyceride-glycerol and fatty acids were measured at 37 degrees C in adipocytes from rats of different weights (135-450 g) and therefore with different mean cell volumes (53-389 pl). Insulin binding per cell increased with increasing cell size and binding was 2.3 times higher in the largest cells than in the smallest cells with tracer alone. The difference was largely accounted for by an increase in the apparent affinity. Influx of methylglucose per cell increased with increasing cell size in the absence of insulin and remained constant as a function of cell size in its presence. The effect of insulin ranged from 11 fold in small cells to 3.5 fold in large cells. The rat of conversion of [U-14C]glucose to CO2 and lipids was about half of the rate of methylglucose transport under all conditions. In contrast, the uptake of deoxyglucose in insulin-stimulated cells decreased markedly with increasing cell size. Increasing cell size caused a small decrease in sensitivity which could be explained by a smaller amont of insulin bound per unit surface area. The results show that increasing cell size/animal weight causes changes in insulin binding which may explain changes in sensitivity. In addition, the hexose transport system is modified in a way which is not explained by changes in insulin binding. Finally, changes in deoxyglucose uptake with cell size do not parallel changes in methylglucose transport.

Adipose Tissue↗
PubMed1986

Hexose transport by chicken cecum during development.

Hexose accumulation during development has been studied in tissue slices from chicken cecum. The age of birds ranged from 0 to 7 weeks after hatch. Ceca were divided into six portions according to their situation either proximal (PC), medial (MC) or distal (DC) to the ileocecal junction. In 0-day-old chicks all segments can accumulate 3-O-methyl-D-glucose (0.5 mmol/l) against a concentration gradient through a phloridzin-sensitive mechanism. Cumulative capacity is lower in DC than in PC and declines with development. Distal segments lose sugar transport ability 1-2 days after hatch whereas the medial region retains some concentrative ability in older birds. In 7-week chickens, PC slices have a similar cumulative ability to that of jejunum (yolk sac region). Kinetic studies showed that in PC the apparent Km for phloridzin-sensitive transport was half that in 1-day- than in 7-week-old birds; apparent Vm increased by 50% in this time range. The ability to transport sugars by the cecum was further confirmed in isolated enterocytes from 5- to 7-week-old chickens using alpha-methyl-D-glucoside (0.1 mmol/l) as substrate. Cell sugar concentration was greater in PC than in jejunal cells and jejunal greater than MC enterocytes. Sugar present in cells from DC was the same as in phloridzin-treated cells. It is concluded that cecal epithelium may play a significant role in the absorption of sugars during development.

3-O-Methylglucose↗
PubMed1985

Contraluminal transport of hexoses in the proximal convolution of the rat kidney in situ.

In order to study contraluminal hexose transport, concentration and time-dependent influx of 3H-2-deoxy-D-glucose from the interstitium into cortical tubular cells has been measured. The influx curves fit to a two parameter kinetics (Km 1.3 +/- 0.2 mmol/l, Jmax 0.67 +/- 0.16 pmol/s X cm) plus an additional diffusion term (with P = 6 X 10(-8) cm2/s) and a distribution ratio extracellular to intracellular amount of 2-deoxy-D-glucose of 1:0.6. Since the extracellular to intracellular free water space as estimated from morphological data was 1:2, one must conclude that glucose has only free access to 1/3 of the cell water. The intracellularly accessible space was augmented when the tubules were preperfused for 10 s with hypotonic saline. Thereby an increase of the compartment into which diffusion occurs was revealed and a final rupture of this intracellular compartment at 1/4 isotonic solutions was observed. Total replacement of ions in the peritubular perfusate by mannitol did not change 2-deoxy-D-glucose influx, indicating that it is Na+-independent. By adding isotonic concentrations of the respective sugars to the capillary perfusate, three degrees of inhibition of 2-deoxy-D-glucose influx could be revealed: strong inhibition by D-glucose, methyl-beta-D-glucoside, D-mannose, 3-O-methyl-D-glucose, 2-deoxy-D-galactose, methyl-beta-D-galactoside and 6-deoxy-D-glucose, moderate inhibition by D-galactose, L-glucose, L-mannose and D-fructose, no or borderline inhibition by methyl alpha-D-glucoside, 2-deoxy-methyl-alpha-D-galactoside, 1-thio-beta-D-glucose, 1-thio-beta-D-galactose, 5-thio-alpha-D-glucose, myo-inositol and mannitol.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Hexose accumulation by enterocytes from the jejunum and rectum of chickens adapted to high and low NaCl intake.

We have studied the effects of adaptation to low NaCl intakes on hexose transport using suspensions of enterocytes isolated from the jejunum and the rectum of the chicken. Animals (12-13 weeks old) were kept for 11 days on either a high-Na+ (HS) or a low Na+ (LS) diet. On day 11, mean serum aldosterone concentration was 46 pg/ml in HS birds and 236 pg/ml in LS birds. Results of transport studies show that: (1) adaptation to a LS diet reduces the cellular 3-oxymethyl-D-glucose cumulative capacity by 40% in the jejunum and is virtually abolished in the rectum; (2) LS adaptation reduces initial alpha-methyl-D-glucoside influx (1 mmol/l) by 22% in the jejunum and by 54% in the rectum; (3) the influx of the membrane potential sensor tetraphenyl-phosphonium (TPP+) in enterocytes strongly suggests that rectal cells of LS birds are significantly depolarized; (4) the presence of 0.1 mmol/l amiloride increases the capacity of the rectal cells of LS birds to establish a sugar gradient across the membrane; (5) incubation of enterocytes with cytochalasin B increases sugar cumulative capacity of the jejunal cells of both HS and LS birds, and has no effect on the rectal cells of LS birds. We conclude that the effects of LS adaptation on sugar transport may involve a reduction in the membrane electrical potential.

Amiloride↗
PubMed1993

Impaired hexose uptake by diploid skin fibroblasts from galactosaemic patients. Connection with cell growth and amino acid metabolism, and possible bearing on late-onset clinical symptoms.

In skin fibroblasts of patients presenting with galactosaemia, either from galactose 1-phosphate uridyltransferase or galactokinase deficiency, a deficit in extracellular glucose utilization was observed. This deficit was constant over 3 weeks of continuous cell growth in a medium containing 5.5 mmol/L glucose as the only hexose, and homologous serum. Levels of glucose utilization by deficient skin fibroblasts were stable at about 65-70% of the glucose utilization of control normal skin fibroblasts. Cell morphology was normal, and cell growth was subnormal during this period. However, the energy provision appeared sufficient for cellular needs since cell growth in this glucose medium was observed not to depend on the presence of extracellular glutamine. In contrast, glutamine was required for growth of galactosaemic fibroblasts cultured in medium containing 5.5 mmol/L galactose. If expressed in many cell types, this impaired glucose uptake would be expected seriously to damage highly glucose-dependent tissues such as the central nervous system. This might be of relevance to the persistent neurological damage observed in many galactosaemic patients in spite of their compliance with an early strict galactose-free diet.

Adolescent↗
PubMed1984

Hepatic hexose transport and the effect of N2-induced anoxia and KCN on this process.

Hepatic hexose transport was characterized using 3-O-methyl-D-glucose, which is not metabolized by the liver. The kinetic parameters determined in the starved state were taken as basal values for the transport system which showed saturation kinetics with high Vmax and Km values of 161 nmol/mg dry wt./min and 39 mM respectively. In the fed state, the Vmax was found to be increased nearly two-fold; this may be due to a phenomenon known as trans-stimulation. The effects of N2-induced anoxia and of KCN were investigated. In the fasted state, anoxia caused the transport characteristics Vmax and Km to decrease nearly two-fold whereas KCN had the opposite effect as the Vmax and Km were increased by three- and two-fold respectively. In the fed state, anoxia and KCN caused a marked decrease in the transport characteristics.

Animals↗
PubMed1984

Acute exposure of rabbit jejunum to ethanol. In vitro uptake of hexoses.

The effect of acute exposure of rabbit jejunum to ethanol on the uptake of three hexoses was examined in vitro. With ethanol present in the preincubation medium for 30 min, or directly in the incubation medium for 6 min, glucose uptake was reduced. Kinetic analysis demonstrated that ethanol in the preincubation medium was associated with a rise in the value of the apparent Michaelis constant (Km*), whereas the inhibition of glucose uptake observed with ethanol present directly in the incubation medium was associated with a reduction in the apparent passive permeability coefficient (Pd*), a reduction in the maximal transport rate (Jdm), and an increase in Km*. When increasing concentrations of ethanol were added to the preincubation or to the incubation medium, there was a reduction in the uptake of both 1 mM and 40 mM glucose, galactose, and 3-O-methyl glucose. The addition of 40 mM galactose or 1 mM phloridzin to 40 mM glucose was associated with a 50% reduction in glucose uptake, but this uptake was not further inhibited by the addition of 6% ethanol (v/v). Similarly, the uptake of 3-O-methyl glucose was inhibited by the addition of 40 mM glucose or galactose but no further reduction in uptake was achieved by adding ethanol. Finally, galactose uptake was inhibited by adding 40 mM glucose or 40 mM 3-O-MG, but the addition of 6% ethanol was associated with no further decline in the uptake of galactose.(ABSTRACT TRUNCATED AT 250 WORDS)

3-O-Methylglucose↗
PubMed1978

Quercetin inhibits hexose transport in a human diploid fibroblast.

The flavonol quercetin, a phloretin analog, inhibits transport of 2-deoxyglucose and 3-O-methylglucose in a cultured human diploid fibroblast. This inhibition is related to transport itself and not to the reported effects of flavonoids on membrane-bound ATPases. From concentration-inhibition curves at several pH's we conclude that uncharged (acid) quercetin (pK = 7.65) is the inhibitory form of the molecule (K1 = 10micron). Quercetin, unlike phloretin, is rapidly degraded in 0.1 N NaOH; the degradation products are weakly inhibitory to hexose transport.

Biological Transport, Active↗
PubMed2001

Differential effects of hexoses and sucrose, and platelet-derived growth factor isoforms on cyclooxygenase-1 and -2 mRNA expression in keloid, hypertrophic scar and granulation tissue fibroblasts.

Cyclooxygenase (COX) is the key enzyme in the formation of prostaglandins in inflammation. In the present study the effects of biomedically relevant hexose sugars (glucose, fructose, galactose, mannose) and sucrose disaccharide on the expression of COX-1 and COX-2 genes were evaluated in granulation tissue fibroblasts, hypertrophic scar fibroblasts and keloid fibroblasts. The effects of three isoforms (AA, AB and BB) of PDGF on COX gene expression in granulation tissue fibroblasts were also examined. All cell lines expressed COX-1 mRNA, whilst fibroblasts derived from abnormal scars did not express COX-2 mRNA. COX-1 mRNA expression was decreased by sugars in granulation tissue fibroblasts and increased in hypertrophic scar fibroblasts. No major changes were seen in keloid fibroblasts. On the other hand, COX-2 mRNA expression in granulation tissue fibroblasts was decreased dramatically in the presence of fructose, mannose and sucrose and moderately in the presence of galactose. All isoforms of PDGF increased COX-1 and COX-2 mRNA expression in granulation tissue fibroblasts, the most marked increases being elicited by PDGF-BB. All fibroblast cell lines studied expressed the COX-1 gene while the COX-2 gene was not expressed by abnormal scar-derived fibroblasts. Further, granulation tissue fibroblasts seemed to behave differently under the influence of sugars compared to hypertrophic scar fibroblasts whilst keloid fibroblasts seemed to be relatively unaffected by sugars. In addition, the PDGF-BB isoform is a potent inducer of COX-2 gene expression in wound fibroblasts. These findings may be relevant to the development of abnormal scars and indicate the need for further studies.

Cells, Cultured↗