The binding of iodinated basic fibroblast growth factor (bFGF) to low‐density heparan sulfate proteoglycan purified from the Engelbreth Holm Swarm (EHS) sarcoma was investigated using different techniques. The tumor clearly contained bFGF, the level being comparable to that found in other tissues such as human or bovine brain. 125I bFGF strongly bound to the basement membrane‐like matrix of EHS frozen sections as revealed by autoradiography. Iodinated bFGF bound to purified heparan sulfate proteoglycan but not to laminin or collagen type IV, three components isolated from the same tumor. In contrast, acidic fibroblast growth factor (aFGF) displayed negligible binding to heparan sulfate proteoglycan. Binding of bFGF to frozen sections and to purified proteoglycan could be strongly inhibited by heparin and was displaced by an excess of unlabeled factor and completely suppressed after heparitinase and heparinase treatments. Binding was a function of the salt concentration and was abolished at 0.6 M NaCl. Scatchard analysis indicated the affinity site had a Kd of about 30 nM, a value 10–15 higher than that recently reported by Moscatelli (J. Cell. Physiol., 131:123–130, 1987) in the case of the low‐affinity binding sites present on the surface of baby hamster kidney (BHK) cells.

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Abstract— Thiamine deficiency produced by administration of pyrithiamine to rats maintained on a thiamine‐deficient diet resulted in a marked disturbance in amino acid and glucose levels of the brain. In the two pyrithiamine‐treated groups of rats (Expt. A and Expt. B) there was a significant decrease in the levels of glutamate (23%, 9%) and aspartate (42%, 57%), and an increase in the levels of glycine (26%, 27%) in the brain, irrespective of whether the animals showed signs of paralysis (Expt. A) or not (Expt. B). as a result of thiamine deficiency. A significant decrease in the levels of γ‐aminobutyrate (22%) and serine (28%) in the brain was also observed in those pyrithiamine‐treated rats which showed signs of paralysis (Expt. A). Threonine content increased by 57% in Expt. A and 40% in Expt. B in the brain of pyrithiamine‐treated rats, but these changes were not statistically significant. The utilization of [U‐14C]glucose into amino acids decreased and accumulation of glucose and [U‐14C]glucose increased significantly in the brain after injection of [U‐14C]glucose to pyrithiamine‐treated rats which showed abnormal neurological symptoms (Expt. A). The decrease in 14C‐content of amino acids was due to decreased conversion of [U‐14C]glucose into alanine, glutamate, glutamine, aspartate and γ‐aminobutyrate. The flux of [14C]glutamate into glutamine and γ‐aminobutyrate also decreased significantly only in the brain of animals paralysed on treatment with pyrithiamine. The decrease in the labelling of, amino acids was attributed to a decrease in the activities of pyruvate dehydrogenase and α‐oxoglutarate dehydrogenase in the brain of pyrithiamine‐treated rats. The measurement of specific radioactivity of glucose, glucose‐6‐phosphate and lactate also indicated a decrease in the activities of glycolytic enzymes in the brain of pyrithiamine‐treated animals in Expt. A only. It was suggested that an alteration in the rate of oxidation in vivo of pyruvate in the brain of thiamine‐deficient rats is controlled by the glycolytic enzymes, probably at the hexokinase level. The lack of neurotoxic effect and absence of significant decrease in the metabolism of [U‐14C]glucose in the brain of pyrithiamine‐treated animals in Expt. B were probably due to the fact that animals in Expt. B were older and weighed more than those in Expt. A, both at the start and the termination of the experiments.

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We present the results of the first evaluation of human placenta extracted basic fibroblast growth factor (bFGF) in a rabbit corneal epithelium wound-healing model. Healing dose-response experiments after selective epithelial wounding with iodine vapors demonstrated that bFGF accelerated the repair process in a saturable manner. Corneal binding of topically applied 125I-labeled bFGF was investigated using radioassay and autoradiographic techniques. Basic FGF was shown to bind specifically to denuded epithelial basement membrane in a very stable fashion and not to the intact epithelium. No transfer of the topical bFGF to the aqueous humor or any intraocular structure could be observed. The stability of this interaction was further demonstrated by reextracting and characterizing the labeled factor from treated corneas. The specificity of the fixation was documented by in vivo topical competition with unlabeled bFGF or heparin. We propose that bFGF-basement membrane interactions play a role in corneal wound healing.

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