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Biomedical subjects

N Carrillo

Publications and source records attributed to N Carrillo.

47 records · Page 3Linked to original sources
PubMed1981

An essential carboxyl group at the nucleotide binding site of ferredoxin-NADP+ oxidoreductase.

Woodward's reagent K (N-ethyl-5-phenylisoxazolium-3'-sulfonate) inactivated both soluble and membrane bound-ferredoxin-NADP+ reductase of spinach chloroplasts. Either NADP+ or NADPh afforded complete protection against modification. Ki and the apparent Kd for protection afforded by NADP+ depended on the ionic strength of the medium. Nucleophylic displacement of reagent bound to the soluble enzyme by [14C]glycine ethyl ester showed that 5 to 6 carboxyl groups/flavin were modified when the diaphorase activity was completely inhibited. In differential labeling experiments using NADP+ as protective agent, it was shown that enzyme inactivation was due to blocking of only 1 carboxyl group/mol. Derivatized reductase did not bind pyridine nucleotides. Protection by NADP+ of the membrane-bound reductase was higher, and the apparent Kd for NADP+ lower, in the light than in the dark. Inactivation increased abruptly with the external pH, indicating a progressive exposure of the carboxyl group as the pH was raised. The results presented suggest (a) the existence of a light-driven conformational change and a pH-dependent transition in membrane-bound ferredoxin-NADP+ reductase; (b) the presence of an essential carboxyl residue in the nucleotide binding site of the reductase.

Binding Sites↗
PubMed1981

Light modulation of chloroplast membrane-bound ferredoxin-NADP+ oxidoreductase.

Light increases the affinity of chloroplast membrane-bound ferredoxin-NADP+ oxidoreductase for its physiological substrates in NADP+ photoreduction, that is, NADP+ and ferredoxin. Light may cause this effect through a conformational change of the enzyme related to the formation of a light-driven delta pH since the effect is prevented by uncouplers. Although the external pH does influence the extent of photoreduction of NADP+ in saturating light, it does not significantly influence the extent of the energy-driven change in affinity of the enzyme for its substrates.

Ammonium Chloride↗
PubMed1980

Effect of Light on Chemical Modification of Chloroplast Ferredoxin-NADP Reductase.

Chemical modification of spinach chloroplasts by phenylglyoxal and dansyl chloride resulted in inhibition of NADP photoreduction. The rate of inactivation was higher with both reagents when modification was carried out in the light with methylviologen or phenazine methosulfate present. Uncouplers prevent the effect of light. Electron transport from water to methylviologen was not affected by the modifiers.The presence of 10 millimolar NADP completely protected the membrane-bound reductase against inactivation by phenylglyoxal. With lower concentrations, protection was higher in the light than in the dark. The apparent dissociation constants of the enzyme-substrate complex for NADP were 0.9 and 0.1 millimolar for the dark and light inactivation, respectively. Inactivation of NADP photoreduction by dansyl chloride was completely prevented by ferredoxin, but only partially by nucleotides.The diaphorase activity was inhibited in chloroplasts modified by phenylglyoxal, but not when modified by dansyl chloride.The results suggest that energizing thylakoid membranes by light induces a conformational change in membrane-bound ferredoxin-NADP reductase, and that the reductase is an allotopic enzyme.

Journal Article↗
PubMedDate not supplied

[Echography of post-vagotomy gallbladder emptying].

Truncal vagotomy has been related to an enlargement of the resting volume and impaired contraction of the gallbladder, and an increased incidence of cholelithiasis, changes that are not reported in selective or highly selective vagotomy. We studied 12 patients, 7 with truncal vagotomy, 2 with selective, 1 with highly selective and 1 patient with subtotal gastrectomy alone. We measured the gallbladder volume and contraction sonographically and compared them with normal values. The patients with truncal vagotomy had an increased resting volume and an impaired gallbladder contraction. The patients with selective vagotomy had a normal resting volume but a decreased gallbladder contraction. We also found cholelithiasis in 2 of our patients with truncal vagotomy, for an incidence of 28%, similar to the ones reported by other authors.

Adult↗
PubMedDate not supplied

[Giant duodenal ulcer].

Giant duodenal ulcers have a high mortality. The clinical, radiological and endoscopic appearance are described. The treatment of choice in patients with giant duodenal ulcer is surgical, the continuous infusion of H-2 blockers is useful before the surgical procedure.

Duodenal Ulcer↗
PubMedDate not supplied

[Acute pancreatitis and diagnostic and therapeutic endoscopic retrograde cholangiopancreatography].

Urgent endoscopic retrograde cholangiopancreatography in acute pancreatitis allows to detect associated biliary disease, display the bilio-pancreatic anatomy to plan optional early surgery and offer an alternative in the treatment with endoscopic sphincterotomy and/or infundibulotomy, in cases of choledocholithiasis and impacted stone at the ampulla of Vater. In relation to the prevalence of biliary lesions in the etiology of acute pancreatitis, the urgent ERCP is a safe and useful procedure that offer diagnosis and treatment, so therefore, it must be considered during the evaluation of patients with acute pancreatitis.

Acute Disease↗
PubMedDate not supplied

[Liver abscess. Diagnosis by the method of opacification].

A 15 min infusion of a 75% iodized solution at 2 cc/k-w produces opacification of the more vascularized organs; hypovascular, necrotic or cystic regions are thus of a different radiological density. In order to show the usefulness of this method in diagnosing a hepatic abscess quickly and topographically, it was applied in 13 cases which had been diagnosed as invading amoebiasis. Hepatography proved to be the most valuable. Positive findings are observed 5 to 7 min after infusion has been completed. The greater density at the edge of the abscess enables its diameter to be measured and the liquid content to be calculated fairly accurately.

Contrast Media↗