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Biomedical subjects

J M Montero

Publications and source records attributed to J M Montero.

31 records · Page 2Linked to original sources
PubMed1984

Dinucleosidetriphosphatase from rat brain.

Rat brain P1,P3-bis(5'-adenosyl)-triphosphate adenylohydrolase (dinucleosidetriphosphatase, EC 3.6.1.29) was purified 1000-fold. The enzyme hydrolyzed diadenosine and diguanosine triphosphates (Km values 14 and 40 microM, and relative V 100 and 40, respectively) to the corresponding nucleoside di and monophosphates. Dixanthosine triphosphate was hydrolyzed at a residual rate. Diadenosine di and tetraphosphates, NAD+, and artificial phosphodiesterase substrates were not hydrolyzed. Bivalent cations [Mg(II), Mn(II) or Ca(II)] were required for activity, but Zn(II) was a competitive inhibitor (Ki = 5 microM). The optimum pH value was about 7.5. A molecular mass of 34 kdalton (gel filtration) and an isoelectric point of 5.5 (chromatofocusing) were found.

Acid Anhydride Hydrolases↗
PubMed1982

Purification and characterization of bovine brain 5'-nucleotidase.

The 5'-nucleotidase located in the cytoplasmic fraction of bovine brain cortex was purified to electrophoretic homogeneity. The molecular weight was 134,000 daltons in the presence of sodium deoxycholate, whereas the enzyme formed high molecular weight aggregates in the absence of detergent. The purified enzyme showed the same kinetic and electrophoretic behaviour as the enzyme present in the original cytoplasmic fraction, and the presence of surfactants did not change the Km and Vm values. The nucleotidase from this source was a phosphohydrolase of 5'-mononucleotides acting on the deoxyribonucleotides and ribonucleotides of purines and pyrimidines. 5'-IMP was the preferred substrate; the optimum pH was 7.5. The study of the influence of the temperature on the initial reaction rates allowed calculation of the delta Ea and delta H degrees values. The variation of Vm and Km with a change in pH suggests the existence of a sulfhydryl group and an imidazole group in the enzyme-substrate complex.

5'-Nucleotidase↗
PubMed1979

Nissen fundoplication.

A personal series of 16 patients treated with Nissen fundoplication for reflux peptic esophagitis with or without hiatal hernia between March 1975 and September 1977 is presented. The average length of followup was 18 months. The age range was 21 to 78. Very good to excellent results were achieved in 94% with a 12.5% morbidity, 6% operative complication rate and 0 mortality. This relatively simple procedure definitely reduces, if not cures, the symptomatology of the often "miserable" patient with intractable reflux peptic esophagitis. The encouraging reports in the recent literature concerning patients treated with this operation recommend its wider use in the future.

Adult↗