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Biomedical subjects

J Cortés

Publications and source records attributed to J Cortés.

At least 19 recordsLinked to original sources
PubMed1990

[Antibiotic prophylaxis with piperacillin in vaginal hysterectomy. Study of 1 dose versus 3 doses].

A homogeneous and consecutive series of 93 patients treated with vaginal hysterectomy is studied in a controlled, randomized clinical essay. The patients were divided in two groups. One of the groups received one single dose of 49 of piperacillin 30 minutes before surgery; the other, three doses of 4 g of the same antibiotic 30 minutes before surgery and 6 & 12 hours after it. No significant difference was found between both groups and therefore it is fair to suppose that one single preoperative dose of piperacillin shows similar efficacy to the usually used three doses, one preoperative and two postoperative.

Bacterial Infections↗
PubMed1990

Immature teratoma primary of the uterine cervix. First case report.

The extragonadal germ cell tumours represent 1-2% out of all the germ cell tumors. The retroperitoneal and the mediastinic spaces are the most common localizations. Visceral localizations are very infrequent. We present a case, the first described in literature, of immature teratoma of the uterine cervix in a 13 year old girl.

Adolescent↗
PubMed1989

Serial trough and peak amikacin levels in plasma as predictors of nephrotoxicity.

We studied 113 patients treated with intravenous amikacin to determine the value of determining serial trough and peak amikacin levels in plasma for predicting nephrotoxicity. Thirteen patients (11.5%) developed renal toxicity, with significant increases from 48 to 96 h in both peak and trough amikacin levels (6.7 +/- 4.7 [standard deviation] days before the serum creatinine rose). The nontoxicity group had no change or even showed decrements in amikacin levels in plasma. A higher nephrotoxicity risk was seen in patients with increments greater than 1 microgram/ml between 48 and 96 h, with odds ratios of 16.4 for trough, 8 for peak, and 7.2 for both levels. We suggest that an increment of at least 1 microgram/ml in amikacin levels in plasma from 48 to 96 h may predict the appearance of renal toxicity.

Acute Kidney Injury↗
PubMed1988

Purification and characterization of the isopenicillin N synthase of Streptomyces lactamdurans.

The isopenicillin N synthase (cyclase) of Streptomyces lactamdurans (syn. Nocardia lactamdurans) has been purified to near homogeneity as judged by SDS-PAGE and isoelectric focusing. This enzyme catalyses the oxidative cyclization of the tripeptide delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine to isopenicillin N. The enzyme required DTT, Fe2+ and oxygen and it was greatly stimulated by ascorbic acid. It was strongly inhibited by Co2+, Zn2+ and Mn2+. Optimal pH and temperature were 7.0 and 25 degrees C (with the assay conditions used), respectively. The apparent Km of isopenicillin N synthase for delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine was 0.18 mM. The enzyme is a monomer with an Mr of 26,500 +/- 1000 and a pI of 6.55.

Chromatography, Gel↗
PubMed1988

The colposcopy and the cone biopsy in the diagnosis, treatment and follow-up of 81 cases of cervical intraepithelial neoplasia.

A conization was performed on 81 patients with histological diagnosis of cervical intraepitelial neoplasia (CIN), whom and previously a rigorous colposcopic examination. 64 patients were younger than 35 years. The previous strict colposcopic examination determined that in none of the cases were the surgical margins of the cone biopsy affected: In 26 cases there was no correlation between the previous biopsy and the histological diagnosis of the cone biopsy. The latter was--higher in degree in 9 cases and, in addition to this, in the 23 histerectomies that were performed after the conization, 7 surgical specimens showed CIN in their histological study. The non-involved surgical margins--that could be obtained in those cases with a careful previous colposcopy,--can not guarantee the exeresis of all the CIN zones. The biopsy of an atypical zone, in a colposcopic extensive lesion, cannot be representative of the whole lesion. In the follow-up--5 years maximum and 1 year minimum--3 relapses had appeared and 9 pregnancies had been diagnosed, that had not showed an increase in the number of premature labours, nor in the cesareas-rate.

Adolescent↗
PubMed1987

Purification and characterization of a 2-oxoglutarate-linked ATP-independent deacetoxycephalosporin C synthase of Streptomyces lactamdurans.

The deacetoxycephalosporin C (DAOC) synthase (expandase) of Streptomyces lactamdurans was highly purified, as shown by SDS-PAGE and isoelectric focusing. The enzyme catalysed the oxidative ring expansion that converts penicillin N into DAOC. The enzyme was very unstable but could be partially stabilized in 25 mM-Tris/HCl, pH 9.0, in the presence of DTT (0.1 mM). The enzyme required 2-oxoglutarate, oxygen and Fe2+, but did not need ATP, ascorbic acid, Mg2+ or K+. The optimum temperature was between 25 and 30 degrees C. The DAOC synthase showed a high specificity for the penicillin substrate. Only penicillin N but not isopenicillin N, penicillin G or 6-aminopenicillanic acid served as substrates. 2-Oxoglutarate analogues were not used as substrates although 2-oxobutyrate and 3-oxoadipate inhibited the enzyme by 100% and 56% respectively. The enzyme was strongly inhibited by Cu2+, Co2+ and Zn2+. The apparent Km values for penicillin N, 2-oxoglutarate and Fe2+ were 52 microM, 3 microM and 71 microM respectively. The enzyme was a monomer with a molecular mass of 27,000 Da +/- 1,000.

Chromatography, Gel↗
PubMed1987

Prolonged (6 months) treatment of chronic hepatitis B virus infection with recombinant leukocyte A interferon.

Twelve hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), hepatitis B virus DNA polymerase (HBV-DNAp) and hepatitis B virus DNA (HBV-DNA) positive patients with chronic active hepatitis (CAH) were treated with doses of either 20 X 10(6) IU/m2 or 10 X 10(6) IU/m2 body surface of recombinant interferon (rIFN)-alpha-2A, I.M., twice a week, during a period of 6 months. No appreciable differences with respect to clinical history, liver function tests and markers of HBV replication between the two groups were apparent at the time of entry into the trial. At the third month of treatment HBV-DNAp became negative in 10 out of 12 patients (83%). After a 15-month follow-up, HBV-DNAp, HBV-DNA and HBeAg were negative in 7 out of 12 patients (38%) (responders). Furthermore, at 24 months, 2 non-responder patients became HBV-DNA and HBV-DNAp negative and one responder lost serum HBsAg. In addition, HBsAg concentration, GPT level and histological Knodell's index decreased significantly in the responder patients, while no changes were observed in non-responders. Five out of six patients who received a low rIFN dose responded to the treatment, and only 2 out of 6 with a higher dose. No unacceptable toxicity was noted in any of the 12 patients. All of them completed the course of treatment. The results suggest that long-term rIFN-alpha-2A therapy has an antiviral effect in CAH due to HBV infection and is well tolerated.

Adult↗
PubMed1986

Glucose regulation of cephamycin biosynthesis in Streptomyces lactamdurans is exerted on the formation of alpha-aminoadipyl-cysteinyl-valine and deacetoxycephalosporin C synthase.

Glucose exerted a concentration-dependent negative regulation on the biosynthesis of cephamycin C by Streptomyces lactamdurans. Formation of the cephamycin precursor delta(alpha-aminoadipyl)-cysteinyl-valine was greatly decreased by excess glucose. The ring-expanding enzyme deacetoxycephalosporin C synthase was strongly repressed by glucose in vivo. Isopenicillin N synthase (cyclase) and isopenicillin N epimerase were not repressed by glucose. However, the activity of isopenicillin N synthase was inhibited in vitro by glucose 6-phosphate, and the activity of deacetoxycephalosporin C synthase was inhibited by inorganic phosphate, glucose 6-phosphate, fructose 2,6-diphosphate and fructose 1,6-diphosphate. The intracellular cAMP content decreased as growth proceeded and remained lower in glucose-supplemented cells than in control cultures. cAMP did not seem to be involved in glucose control of cephamycin biosynthesis.

Amino Acid Isomerases↗