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Biomedical subjects

A Mendoza

Publications and source records attributed to A Mendoza.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

The enhancement of ammonium assimilation in Rhizobium etli prevents nodulation of Phaseolus vulgaris.

The modification of the ammonium assimilation pathway of Rhizobium etli (GS-GOGAT) by adding an additional ammonium assimilation enzyme, GDH, strongly affects its symbiotic interaction with beans. The plasmid pAM1a, based in the stable vector pTR101 (M. Weinstein, R. C. Roberts, and D. R. Helsinki, J. Bacteriol. 174,7486-7489, 1992), containing the Escherichia coli gdhA gene flanked by two transcription-translation terminators was constructed. The expression of GDH in both, the wild type (CFN42/pAM1a) and a ntrC- mutant (CFN2012/pAM1a) R. etli strains, gave a similar metabolic effect, i.e., high GDH and reduced GOGAT activities, and an increased synthesis and excretion of several amino acids. The total inhibition of bean nodulation was observed when the minimum optimal inoculum of R. etli CFN42/pAM1a was used; however, an effective symbiosis occurred with the CFN2012/pAM1a mutant strain. While a total inhibition of the induction of the nodA gene by bean root exudate or by naringenin was observed in the CFN42/pAM1a strain, at 10 mM ammonium, the CFN2012/pAM1a showed an optimal nodA gene induction. A correlation between nodA gene induction, Nod factor production, and nodulation was observed. We conclude that in R. etli, there is a down-regulation of nod gene expression and nodulation when a high internal nitrogen content is built up by the presence of a functional GDH and that NtrC is involved in such regulation. An instability of the plasmid harboring the gdhA gene was observed during symbiosis, indicating a strong selection against cells containing this plasmid.

Down-Regulation↗
PubMedDate not supplied

Two-year follow-up of laser in situ keratomileusis for hyperopia.

PURPOSE: To evaluate excimer laser in situ keratomileusis (LASIK) for hyperopia and its predictability. METHODS: We performed a retrospective study of 100 eyes that had LASIK for hyperopia to assess predictability and long-term stability of refractive results. The Chiron Automated Corneal Shaper was used to create the flap and the Keracor 117CT Chiron-Technolas excimer laser with the plano-scan program was used to ablate all corneas. RESULTS: Mean baseline spherical equivalent manifest refraction was +4.50 +/- 1.73 D (range, +1.25 to +8.50 D). Six months after LASIK, mean manifest spherical equivalent refraction was +0.72 +/- 1.87 D (range, -1.75 to +2.50 D), at 1 year, +0.88 +/- 1.73 D (range, -1.25 to +2.50 D), and at 2 years, +0.85 +/- 1.74 D (range, -0.50 to +2.75 D). Two years after LASIK, 45 eyes (74%) were within +/-1.00 D of intended correction and within +/-1.00 D of emmetropia. Uncorrected visual acuity was 20/40 or better in 50 eyes (82%) at 2 years; 29 eyes (37%) saw 20/20 or better. Undercorrection occurred more frequently in eyes with preoperative keratometric power of more than 45.00 D, when ablation zones less than 6 mm were used and when higher amounts of hyperopic correction were required. CONCLUSION: LASIK with the Keracor 117CT excimer laser appears to be an effective and safe procedure to correct hyperopia. Preoperative keratometric power, amount of hyperopia, and ablation zone diameter affect the efficacy and long-term stability of the procedure.

Adult↗
PubMedDate not supplied

Production of a rabbit anti-cockatiel immunoglobulin G and characterization of its cross-reactivities with immunoglobulin G of other psittacine species.

The purpose of this work was to produce rabbit anti-cockatiel immunoglobulin G (IgG) and compare its cross-reactivity with sera from eight other psittacine birds: Quaker parakeet, budgerigar, green-wing macaw, blue-fronted Amazon parrot, eclectus parrot, African grey parrot, Patagonian conure, Moluccan cockatoo. Cockatiel IgG did not bind to protein A or G; therefore, these proteins could not be used in column chromatography to isolate the IgG. A combination of serum IgG precipitation by ammonium sulfate and yolk IgG extraction from egg was loaded in sodium dodecyl sulfate-polyacrylamide gel upon which the IgG was resolved by electrophoresis. The resolved IgG in sodium dodecyl sulfate-polyacrylamide gel was stained with Coomassie blue, cut, crushed in phosphate-buffered saline, and injected into rabbits. The rabbit anti-cockatiel IgG produced in this way reacted with a single protein in gel immunodiffusion assay with all nine psittacine bird sera but not with those of chicken and ostrich. Immunoelectrophoresis confirmed the cross-reactivity of different psittacine sera with the anti-cockatiel IgG serum but not with ostrich and chicken sera. This antiserum detected antibody responses in sera from cockatiels vaccinated against chlamydial major outer membrane protein in an immunoblot assay.

Animals↗
PubMedDate not supplied

[Epidemiology of primary dystonia].

INTRODUCTION: Dystonia is the most difficult disorder of movement to recognize, and in which errors of diagnosis most often occur. DEVELOPMENT: We review the classification of the dystonias and the most important features of the different subdivisions. With regard to epidemiology, the exact incidence and prevalence of primary dystonia are not known. Figures vary considerably depending on the source, method of study and ethnic group of the population studied. In Europe the only study made of focal dystonias was carried out in Segovia, where the prevalence was about 300 persons per million. Finally we discuss some recent genetic findings related to the dystonias, which should stimulate more detailed studies to clarify the genetic basis of focal dystonias.

Age of Onset↗
PubMedDate not supplied

[Characteristics of adolescent and adult young women diagnosed with human papilloma virus infection at the Center for Research on Human Reproduction (CIRH)].

We reviewed 239 charts of adolescents and young adults, who visited our clinic. The purpose was to know the incidence of the Human Papiloma Virus infection (HPVI), diagnosed by Pap's smears, and the relationship to a population with some gynecological and sociodemographic characteristics. The women age population was between 14-24 years old with a mean age of 19.9 years. Seventy (29.3%) were PIV positive and 169 (70.7%) negatives. About 75% among both groups (PIV + and -) began active sexual life between 15-19 years old. Among the women with 4 or more sexual partners, 55.6% were HPVI positive. About 60% of all women had never used any method before being admitted to the clinic. In this study there is no correlation between IVSA and HPVI. We do demonstrate that the greater the number of sexual partners, the highest the risk of a sexual acquired disease.

Adolescent↗
PubMedDate not supplied

Recurrent autoimmune LKM hepatitis with multiple relapses.

We describe three females who since childhood and puberty have presented with several relapsing episodes of acute or chronic LKM positive hepatitis. Many episodes resolved spontaneously with recovery of normal liver function, although treatment with steroids, steroids/azathioprine was used at occasions. No clear pattern of precipitating factors has emerged though in some cases possible temporal relationship of episodes to menarche, oral contraceptives use or pregnancy has suggested a role for female sex hormones. We discuss briefly the possible mechanisms of LKM positive hepatitis, particularly in terms of drugs as possible trigger factors.

Adult↗
PubMedDate not supplied

[Clinico-epidemiological study of neurolisteriosis in the province of Segovia].

INTRODUCTION: Listeria monocytogenes is a microorganism with marked tropism towards the central nervous system. One of the commonest forms of presentation is as a meningeal infection. The objective of this study is to describe the epidemiological, clinical and laboratory characteristics and therapeutic implications. PATIENTS AND METHODS: We made a retrospective analysis of four patients, admitted to hospital with the diagnosis of meningeal infection and positive culture for L. monocytogenes in the cerebrospinal fluid (CSF), who were admitted to our centre between 1 January 1996 and 31 December 2000. The overall rate of meningitis due to L. monocytogenes in the province of Segovia is similar to that reported from the USA and Europe (six cases per million inhabitants per year). All the patients were male, aged between 19 and 79 years. The commonest form of presentation was a meningeal syndrome. Analysis of the CSF showed pleocytosis with high protein and low glucose levels. Gram staining was negative in all cases. Initial empirical treatment proved to be correct in two of the four patients. The only predisposing factors observed were alcoholism and diabetes mellitus. All four cases recovered. CONCLUSION: We emphasize the difficulty in diagnosing meningitis due to L. monocytogenes, since the presenting symptoms are relatively non specific, CSF analysis gives variable results and Gram staining is of little use. Clinical suspicion is important so that specific antibiotic treatment may be given to improve the prognosis.

Adult↗
PubMedDate not supplied

Rheumatoid factor activity in serum and bronchoalveolar lavage fluid from patients with acute hypersensitivity pneumonitis.

The presence of rheumatoid factor was detected in both serum and bronchoalveolar lavage fluid (BALF) from patients with acute pigeon breeder's disease. IgM rheumatoid factor was positive in 14 of 20 serum samples and 6 of 20 BALF samples by ELISA. In contrast, negative results were found in 20 healthy subjects with a history of avian antigen exposure, as well as in the serum and BALF from 10 normal subjects. The simultaneous presence of rheumatoid factor in serum and BALF occurred in five patients, and four of them revealed high levels of rheumatoid factor in BALF in comparison with serum determinations. These abnormalities may play an important role during the acute inflammatory reaction in hypersensitivity pneumonitis.

Adult↗
PubMedDate not supplied

A statewide early defibrillation initiative including laypersons and outcome reporting.

Rapid delivery of defibrillatory shocks increases survival in patients with cardiac arrest. The automated external defibrillator interprets cardiac rhythms and delivers electrical shocks, permitting appropriate defibrillation by persons with minimal training. California initiated a program for early defibrillation by basic emergency medical technicians, using manual or automated external defibrillators, and by public safety personnel (fire fighters, peace officers, and public lifeguards), using automated external defibrillators. The program includes a system for reporting outcomes statewide. In the first 46 months under this program, 1487 patients received defibrillatory shocks; 1009 (68%) of these patients had witnessed ventricular fibrillation. Of the latter group, 191 were discharged from the hospital, representing 19% of those with witnessed ventricular fibrillation and 13% of all patients who had had shocks applied. California also implemented a framework of training and medical direction for defibrillation by laypersons using automated external defibrillators. Early defibrillation by basic emergency medical technicians and public safety personnel, encouraged by appropriate regulatory changes, results in gratifying survival rates.

California↗
PubMedDate not supplied

[Myxoma of the right ventricle: report of a clinical case and review of the literature].

We studied a seventeen year old female patient with clinical manifestations of pulmonary embolism. A Two-Dimensional echocardiography showed the presence of a right intraventricular mass. It was surgically removed and the histopathological study showed it to be a myxoma. The recovery of the patient was uneventful. This is the first case of a right ventricular myxoma diagnosed during life in our hospital. The medical literature describing this unusual location is reviewed.

Adolescent↗