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Biomedical subjects

J Mora

Publications and source records attributed to J Mora.

At least 91 records · Page 5Linked to original sources
PubMed1997

MAG3 renogram deconvolution in kidney transplantation: utility of the measurement of initial tracer uptake.

UNLABELLED: The study of renal retention function by deconvolution analysis of renographic curves is useful to calculate quantitative parameters in renal studies. The aim of the work is to evaluate the usefulness of 99mTc-MAG3 renogram deconvolution in renal function monitoring of kidney graft recipients. METHODS: Forty-three kidney grafts and 112 renograms were studied: 41 were diagnosed as functioning graft, 35 as acute tubular necrosis, 24 as acute rejection, 8 as obstruction and 4 as cyclosporin toxicity. The parameters calculated were mean transit time (MTT), time at 20% of renal retention function (T20) and initial uptake (IU). RESULTS: MTT and T20 were significantly longer in obstructives than in functioning grafts (p < 0.001). Initial uptake was significantly lower in acute tubular necrosis (ATN) and acute rejection (p < 0.001) and in obstructives (p < 0.05) than in functioning grafts. The joint evaluation of MTT and IU allowed to diagnose cases with graft function severely impaired. CONCLUSION: Initial uptake is useful in evaluating post-transplantation complications and in combination with MTT and T20 reflects renal dysfunction severity.

Adult↗
PubMed1997

Growing teratoma syndrome: experience of a single institution.

OBJECTIVE: To analyze the clinical outcome of patients diagnosed with growing teratoma syndrome (GTS) at a single center during a long follow-up. PATIENTS AND METHODS: Eleven patients with GTS are reported. GTS lesions were located in the metastatic sites involved at disease presentation. Involved sites were: retroperitoneum in 9 patients; lung in 3; supraclavicular lymph nodes in 2, and inguinal lymph nodes in 1. Surgical resection of the masses was the treatment of choice. RESULTS: Twenty-four surgical procedures were performed: 4 thoracotomies; 2 supraclavicular; 1 inguinal, and 17 retroperitoneal node resections. Three patients have not relapsed since surgery of the masses, at 37+, 110+ and 118+ months. Eight patients have relapsed, 6 with mature teratoma and 2 (22%) with cancer. To date, all the patients are alive, 6 of them without disease and 5 with teratoma after resection of the masses. CONCLUSIONS: GTS is an infrequent entity. Involved sites are only at locations previously affected by the disease. The treatment of choice is surgical resection but recurrence is common. Efforts should be done to complete resection of the masses.

Adolescent↗
PubMed1996

Different hCG assays to measure ectopic hCG secretion in bladder carcinoma patients.

We evaluated the clinical performance of assays measuring intact human chorionic gonadotropin alone (i-hCG), intact and nicked human chorionic gonadotropin (i-hCG and hCGn), free beta-subunit (free beta-hCG) and total beta-human chorionic gonadotropin (t-hCG) using different commercial kits, in a group of bladder carcinoma patients with ectopic human chorionic gonadotropin (hCG) secretion, at diagnosis and during treatment. The diagnostic sensitivity obtained ranged between 63.6% and 75.7% (t-hCG assays), 72.7% (free beta-hCG assay), 18.2% (i-hCG and hCGn) and 6% (i-hCG assay). Median increases of hCG during treatment in patients with chemotherapy resistance ranged from 4.9 to 6.9 for t-hCG and free beta-hCG assays and from 1.4 to 3.2 for i-hCG and i-hCG plus hCGn assays. Median decreases when chemotherapy was efficient ranged from 2.8 to 3.3 (t-hCG and free beta-hCG assays) and from 1.1 to 1.5 (i-hCG and i-hCG plus hCGn assays). We conclude that t-hCG and free beta-hCG are the most suitable assays for the management of bladder carcinoma patients as the ectopic secretion of chorionic gonadotropin is mainly due to the free beta-subunit.

Adult↗
PubMed1996

Simultaneous administration of 99Tcm-HMPAO-labelled autologous leukocytes and 111In-labelled non-specific polyclonal human immunoglobulin G in bone and joint infections.

The aim of this study was to investigate the ability of 111In-labelled human polyclonal immunoglobulin G (111In-IgG) to localize bone and joint infections compared with 99Tcm-HMAPO-labelled leukocytes (99Tcm-WBC). Thirty-four patients routinely referred for investigation of bone and joint infections were studied. In all patients, a bone scan using 99Tcm-MDP was initially obtained. Subsequently, 99Tcm-WBC and 111In-IgG were simultaneously injected and images obtained at 30 min, 4 h and 24 h post-injection. Diagnostic accuracy was established by bacteriology of specimens obtained by needle aspiration and/or surgery, other imaging methods and clinical follow-up. The images were read by three experienced observers blinded to any other information; the clinical suspicion of infection and the diagnosis were established when two observers agreed. Infection was confirmed in 11 patients. The 99Tcm-WBC scans gave 8 true-positive, 5 false-positive, 18 true-negative and 3 false-negative results. With 111In-IgG, the figures were 7, 6, 17 and 4, respectively. The sensitivity, specificity and accuracy were 72.7%, 78.2% and 76.4% respectively for the labelled leukocytes and 63.6%, 73.9% and 70.6% respectively for 111In-IgG. There was greater agreement between the observers with 99Tcm-WBC than 111In-IgG. In this study, 111In-IgG was less sensitive and less specific than 99Tcm-WBC scintigraphy for the diagnosis of chronic infections, but these differences were not significant. Both tracers appear to be useful in the diagnosis of bone and joint infections. However, our results were less reliable for the diagnosis of an infected prosthesis.

Adult↗
PubMed1996

Regulatory proteins and cis-acting elements involved in the transcriptional control of Rhizobium etli reiterated nifH genes.

In Rhizobium etli the nitrogenase reductase genes are reiterated. Strain CE3 has three copies; nifHa and nifHb form part of nifHDK operons with the nitrogenase structural genes, while nifHc is linked to a truncated nifD homolog. Their sequences are identical up to 6 residues upstream from a sigma54-dependent promoter. A remarkable difference among them is the absence of canonical NifA binding sites upstream of nifHc while a canonical binding site is located 200 bp upstream of nifHa and nifHb. To evaluate the transcriptional regulation of the reiterated nifH genes, we constructed fusions of nifHa and nifHc with the lacZ gene of Escherichia coli. Both genes were expressed at maximum levels under 1% oxygen in free-living cultures, and their expression declined as the oxygen concentration was increased. This expression was dependent on the integrity of nifA, and nifHc was expressed at higher levels than nifHa. The same pattern was observed with root nodule bacteroids. Expression of both genes in E. coli required sigma54 in addition to NifA bound to the upstream activator sequence. In vivo dimethyl sulfate footprinting analyses showed that NifA binds to the canonical site upstream of nifHa and to a TGT half-site 6 nucleotides further upstream. NifA protected an imperfect binding site upstream of nijHc at position 85 from the promoter. The integration host factor stimulated each gene differently, nifHa being more dependent on this protein. The above results correlate the asymmetric arrangement of cis-acting elements with a differential expression of the reiterated nifH genes, both in culture and during symbiosis with bean plants.

Base Sequence↗
PubMed1996

Pyruvate carboxylase from Rhizobium etli: mutant characterization, nucleotide sequence, and physiological role.

Pyruvate carboxylase (PYC), a biotin-dependent enzyme which catalyzes the conversion of pyruvate to oxaloacetate, was hypothesized to play an important anaplerotic role in the growth of Rhizobium etli during serial subcultivation in minimal media containing succinate (S. Encarnación, M. Dunn, K. Willms, and J. Mora, J. Bacteriol. 177:3058-3066, 1995). R. etli and R. tropici pyc::Tn5-mob mutants were selected for their inability to grow in minimal medium with pyruvate as a sole carbon source. During serial subcultivation in minimal medium containing 30 mM succinate, the R. etli parent and pyc mutant strains exhibited similar decreases in growth rate with each subculture. Supplementation of the medium with biotin prevented the growth decrease of the parent but not the mutant strain, indicating that PYC was necessary for the growth of R. etli under these conditions. The R. tropici pyc mutant grew normally in subcultures regardless of biotin supplementation. The symbiotic phenotypes of the pyc mutants from both species were similar to those of the parent strains. The R. etli pyc was cloned, sequenced, and found to encode a 126-kDa protein of 1,154 amino acids. The deduced amino acid sequence is highly homologous to other PYC sequences, and the catalytic domains involved in carboxylation, pyruvate binding, and biotinylation are conserved. The sequence and biochemical data show that the R. etli PYC is a member of the alpha4, homotetrameric, acetyl coenzyme A-activated class of PYCs.

Amino Acid Sequence↗
PubMed1996

Genetic and physiological characterization of a Rhizobium etli mutant strain unable to synthesize poly-beta-hydroxybutyrate.

Rhizobium etli accumulates poly-beta-hydroxybutyrate (PHB) in symbiosis and in free life. PHB is a reserve material that serves as a carbon and/or electron sink when optimal growth conditions are not met. It has been suggested that in symbiosis PHB can prolong nitrogen fixation until the last stages of seed development, but experiments to test this proposition have not been done until now. To address these questions in a direct way, we constructed an R. etli PHB-negative mutant by the insertion of an Omega-Km interposon within the PHB synthase structural gene (phaC). The identification and sequence of the R. etli phaC gene are also reported here. Physiological studies showed that the PHB-negative mutant strain was unable to synthesize PHB and excreted more lactate, acetate, pyruvate, beta-hydroxybutyrate, fumarate, and malate than the wild-type strain. The NAD+/NADH ratio in the mutant strain was lower than that in the parent strain. The oxidative capacity of the PHB-negative mutant was reduced. Accordingly, the ability to grow in minimal medium supplemented with glucose or pyruvate was severely diminished in the mutant strain. We propose that in free life PHB synthesis sequesters reductive power, allowing the tricarboxylic acid cycle to proceed under conditions in which oxygen is a limiting factor. In symbiosis with Phaseolus vulgaris, the PHB-negative mutant induced nodules that prolonged the capacity to fix nitrogen.

Acyltransferases↗
PubMed1996

Penetration of enrofloxacin and ciprofloxacin into breast milk, and pharmacokinetics of the drugs in lactating rabbits and neonatal offspring.

OBJECTIVE: To determine the pharmacokinetics and milk penetration of enrofloxacin (ENR) and ciprofloxacin (CIP) in lactating rabbits and their disposition in suckling rabbits. DESIGN: Prospective cross-over study. ANIMALS: 6 lactating New Zeland White rabbits and their offspring (16 days after parturition). PROCEDURE: Serial plasma and milk samples were assayed by use of a high-performance liquid chromatography technique. In vitro protein binding in plasma and skim milk was measured by ultrafiltration. Skim-to-whole milk ratio also was determined. The time course of ENR and CIP was fitted by nonlinear least squares regression analysis, and the pharmacokinetic variables were compared. RESULTS: The time courses of ENR and CIP in plasma were similar in lactating adult rabbits (mean body clearances, 23.9 and 27.2 ml/min/kg of body weight, for ENR and CIP, respectively). Observed milk-to-plasma ratios (M/P) were determined, using the area under the milk and plasma concentration versus time profiles (ENR, 2.59; CIP, 3.61). Predicted M/P (ENR, 6.35; CIP, 3.04) were calculated from in vitro measurements. Body clearance calculated for ENR and CIP in suckling rabbit pups involved a decrease of 80 and 74%, respectively, over that found in lactating animals. CONCLUSIONS: Observed CIP M/P were correlated to predicted values, which strengthens the argument that CIP passes into the milk by nonionic diffusion. The lack of correlation between observed and predicted ENR M/P pointed out that ENR undergoes faster elimination from milk than that predicted by the diffusional model. Diminished elimination capacity observed in suckling rabbits would result in greater exposure than that predicted from concentrations alone.

Animals↗
PubMed1995

Alpha-fetoprotein-concanavalin A binding as a marker to discriminate between germ cell tumours and liver diseases.

In order to differentiate whether slight alpha-fetoprotein (AFP) increases observed in any patient are due to germ cell tumours (GCT) or to liver diseases (including hepatotoxicity of chemotherapy), we measured the binding ratio of the AFP to concanavalin A (ConA). A total of 218 serum samples were studied: 102 samples from 72 GCT patients and 116 from patients with liver diseases. Considering a cut-off value to be a ConA binding ratio of 15%, we distinguished AFP produced by GCT (> 15%) from AFP produced by tumoral and non-tumoral liver diseases (< or = 15%) with a sensitivity of 98% and specificity of 100%. The difference between mean ConA binding ratios was statistically significant (P < 0.0001). We did not distinguish AFP produced by tumoral and non-tumoral liver diseases. ConA binding ratio may be a sensitive index to distinguish whether an increase of AFP concentration as low as 15 U/ml in a GCT patient during the follow-up is produced by the tumour or by liver dysfunction (including hepatotoxicity of chemotherapy).

Biomarkers, Tumor↗
PubMed1995

Fermentative and aerobic metabolism in Rhizobium etli.

Strains of Rhizobium etli, Rhizobium meliloti, and Rhizobium tropici decreased their capacity to grow after successive subcultures in minimal medium, with a pattern characteristic for each species. During the growth of R. etli CE 3 in minimal medium (MM), a fermentation-like response was apparent: the O2 content was reduced and, simultaneously, organic acids and amino acids were excreted and poly-beta-hydroxybutyrate (PHB) was accumulated. Some of the organic acids excreted into the medium were tricarboxylic acid (TCA) cycle intermediates, and, concomitantly, the activities of several TCA cycle and auxiliary enzymes decreased substantially or became undetectable. Optimal and sustained growth and a low PHB content were found in R. etli CE 3 when it was grown in MM inoculated at a low cell density with O2 maintained at 20% or with the addition of supplements that have an effect on the supply of substrates for the TCA cycle. In the presence of supplements such as biotin or thiamine, no amino acids were excreted and the organic acids already excreted into the medium were later reutilized. Levels of enzyme activities in cells from supplemented cultures indicated that carbon flux through the TCA cycle was maintained, which did not happen in MM. It is proposed that the fermentative state in Rhizobium species is triggered by a cell density signal that results in the regulation of some of the enzymes responsible for the flux of carbon through the TCA cycle and that this in turn determines how much carbon is available for the synthesis and accumulation of PHB. The fermentative state of free-living Rhizobium species may be closely related to the metabolism that these bacteria express during symbiosis.

Aerobiosis↗
PubMed1995

111In-octreotide and 99mTc(V)-dimercaptosuccinic acid studies in the imaging of recurrent medullary thyroid carcinoma.

Detection of recurrence from medullary thyroid carcinoma (MTC) remains a diagnostic problem, especially when increased serum tumour marker levels suggest recurrence and conventional imaging techniques are non-diagnostic. In this study, we performed 111In-octreotide and 99mTc(V)-dimercaptosuccinic acid (DMSA) scans in a series of eleven patients with MTC presenting with elevated serum tumour markers after surgery. 111In-octreotide whole body studies detected tumour in six of the eleven patients studied and detected nine tumoral localizations. 99mTc(V)-DMSA whole body studies detected tumour in five of the eleven patients studied and eight tumoral localizations. 111In-octreotide and 99mTc(V)-DMSA studies detected recurrence in all four patients with basal calcitonin levels above 1000 ng/l. We conclude that 111In-octreotide and 99mTc(V)-DMSA studies have limited sensitivity to detect recurrence in patients with MTC, although their sensitivity may improve with high serum calcitonin levels. These radionuclide imaging techniques should be employed when conventional imaging techniques are negative or inconclusive or, in the case of 111In-octreotide studies, should be employed when we went to investigate the presence of somatostatin receptors that provide the basis for treatment with somatostatin analogues.

Adult↗
PubMed1995

[Use of the laryngeal mask in pediatric surgery].

The laryngeal mask is a new method in the control of the airway. In this study we assess the haemodynamic response during the insertion of the laryngeal mask, incidence of complications and recovery from anaesthesia after its use. We also check if the laryngeal mask is easy to place into the patient airway and its versatility in pediatric patients. We have obtain that the use of the laryngeal mask airway is a safe technique, with few complications, easy to learn and with a short recovery time.

Adolescent↗
PubMed1994

Detection of steroid receptors in breast cancer: relationship between EIA and IHC methods.

The efficiency of EIA and IHC (frozen tissue) in the detection of ER and PR in 51 breast cancers were compared. ER were detected in 51% of cases by IHC and in 49% of tumours by EIA. PR were detected in 56.8% of cases by IHC and in 54.8% of tumours by EIA. Concordance of the results of IHC and EIA reached 78.4% in ER and 82.4% in PR detection. Discordance between IHC and EIA seems to be related to minor changes in sensibility of methods, but we cannot conclude that one of the two techniques is superior to the other in the detection of hormonal receptors. There is a common trend of association between low grade of histologic or nuclear malignancy and a high expression of hormonal receptors.

Breast Neoplasms↗
PubMed1994

Alcohol-related expectations among Mexican-American women.

The article explores alcohol expectations among Mexican-American women utilizing the Alcohol Expectancy Questionnaire and a series of quantity/frequency alcohol use measures. The results indicate that Mexican-American women generally have similar expectations about the benefits of alcohol use as women in the larger population. Within the sample of Mexican-American women however, there were differences in alcohol expectations based on occupational status and acculturation level: those Mexican-American women who are more acculturated and hold higher professional status occupations have higher expectations of the benefits of alcohol use than less acculturated Mexican-American women in blue-collar or service occupations.

Acculturation↗