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J Velasco

Publications and source records attributed to J Velasco.

At least 55 records · Page 3Linked to original sources
PubMed1997

Expression of the cefG gene is limiting for cephalosporin biosynthesis in Acremonium chrysogenum.

The conversion of deacetylcephalosporin C to cephalosporin C is inefficient in most Acremonium chrysogenum strains. The cefG gene, which encodes deacetylcephalosporin C acetyltransferase, is expressed very poorly in A. chrysogenum as compared to other genes of the cephalosporin pathway. Introduction of additional copies of the cefG gene with its native promoter (in two different constructions with upstream regions of 1056 bp and 538 bp respectively) did not produce a significant increase of the steady-state level of the cefG transcript. Expression of the cefG gene from the promoters of (i) the glyceraldehyde-3-phosphate dehydrogenase (gpd) gene of Aspergillus nidulans, (ii) the glucoamylase (gla) gene of Aspergillus niger, (iii) the glutamate dehydrogenase (gdh) and (iv) the isopenicillin N synthase (pcbC) genes of Penicillium chrysogenum, led to very high steady-state levels of cefG transcript and to increased deacetylcephalosporin-C acetyltransferase protein concentration (as shown by immunoblotting) and enzyme activity in the transformants. Southern analysis showed that integration of the new constructions occurred at sites different from that of the endogenous cefG gene. Cephalosporin production was increased two- to threefold in A. chrysogenum C10 transformed with constructions in which the cefG gene was expressed from the gdh or gpd promoters as a result of a more efficient acetylation of deacetylcephalosporin C.

Acetyltransferases↗
PubMed1997

Energy expenditure in patients with multiple organ failure.

We measured the level of resting energy expenditure (BEE) and its evolution in patients with multiple organ failure (MOF). We studied 30 patients requiring mechanical ventilation and sedation. REE was measured by means of a closed circuit method on days 1-5, 7, 10 and 14 after initiating the protocol. REE values between 115% and 145% of the REE calculated from the Harris-Benedict's formula were considered as moderate hypermetabolism and values above 145% as severe hypermetabolism. A predictive formula for determining caloric requirements was developed and validated in another 25 MOF patients. In the study group, 25 patients presented moderate hypermetabolism (83%) and two severe hypermetabolism(7%). Mean REE in the whole group was stable but individual patients may have had a large variability in REE. The anthropometric variables, body temperature and reason for admission predicted the REE with a coefficient of determination of 0.73, according to the model: REE= -3295 + 105.5S - 8A + 11.7 W + 7.7 H + 93.2 T + 123.1 Tr - 145.6 Su where: S = sex (male = 1, female = 0); A: age in years; W: weight in Kg; H: height in cm; T: temperature in degrees C; Tr: trauma (Tr = 1); Su: surgical (Su = 1). The reliability of the model, taken from the validation group, showed that the shrinkage was 0.8%. In conclusion, when MOF patients are sedated they present moderate hypermetabolism. Day-to-day variability of REE in the individual patients and the large variability in estimating REE with our formula preclude its clinical utility and we recommend to measure REE in MOF patients.

Journal Article↗
PubMed1997

How to treat coexistent mental illness and substance abuse.

Integration of mental illness and substance abuse treatments is important for patients with "dual diagnosis", the coexistence of an emotional ailment and a chemical dependency. Such comorbidity is usually associated with a poor prognosis. Both disorders require appropriate therapy so that remission of psychiatric symptoms and maintenance of sobriety become reachable goals for these individuals. A joint therapeutic approach improves outcome, functional expectation, and community adjustment.

Comorbidity↗
PubMed1997

Antibody and delayed-type hypersensitivity responses to Ochrobactrum anthropi cytosolic and outer membrane antigens in infections by smooth and rough Brucella spp.

Immunological cross-reactions between Brucella spp. and Ochrobactrum anthropi were investigated in animals and humans naturally infected by Brucella spp. and in experimentally infected rams (Brucella ovis infected), rabbits (Brucella melitensis infected), and mice (B. melitensis and Brucella abortus infected). In the animals tested, O. anthropi cytosolic proteins evoked a delayed-type hypersensitivity reaction of a frequency and intensity similar to that observed with B. melitensis brucellin. O. anthropi cytosolic proteins also reacted in gel precipitation tests with antibodies in sera from Brucella natural hosts with a frequency similar to that observed with B. melitensis proteins, and absorption experiments and immunoblotting showed antibodies to both Brucella-specific proteins and proteins common to Brucella and O. anthropi. No antibodies to O. anthropi cytosolic proteins were detected in the sera of Brucella-free hosts. Immunoblotting with sera of Brucella-infected sheep and goats showed immunoglobulin G (IgG) to Brucella group 3 outer membrane proteins and to O. anthropi proteins of similar molecular weight. No IgG to the O-specific polysaccharide of O. anthropi lipopolysaccharide was detected in the sera of Brucella-infected hosts. The sera of sheep, goats, and rabbits infected with B. melitensis contained IgG to O. anthropi rough lipopolysaccharide and lipid A, and B. ovis and O. anthropi rough lipopolysaccharides showed equal reactivities with IgG in the sera of B. ovis-infected rams. The findings show that the immunoresponse of Brucella-infected hosts to protein antigens is not necessarily specific for brucellae and suggest that the presence of O. anthropi or some related bacteria explains the previously described reactivities to Brucella rough lipopolysaccharide and outer membrane proteins in healthy animals.

Animals↗
PubMed1997

Intraoperative ultrasound in the management of liver neoplasms.

The purpose of this study was to determine the impact of intraoperative ultrasound (IOUS) on the management of patients with neoplasms of the liver. Fifty-nine patients with liver neoplasms (primary, 6; metastatic, 53) and without pre- or intraoperative evidence of extrahepatic disease underwent laparotomy for possible liver resection. Preoperative imaging studies included external ultrasound (n = 12), magnetic resonance imaging (n = 11), and/or computed tomography (n = 57). Intraoperative evaluation on all patients included inspection, bimanual palpation, and ultrasonography. External ultrasound, magnetic resonance imaging, and computed tomography identified all intraoperatively confirmed liver neoplasms in 33, 45, and 67 per cent of cases, respectively. Unsuspected neoplasms were identified in 12 patients (20%) by inspection/palpation and in 19 patients (32%) by IOUS. In eight patients (14%), the occult neoplasms were identified only IOUS, and in one patient the neoplasms were identified only by inspection/palpation. Occult neoplasms identified by IOUS were characterized by small size (less than 2 cm). Findings from the intraoperative evaluation, such as unsuspected neoplasms and vascular proximity or invasion, altered the preoperative plan in 20 (34%) patients. Inspection, and particularly palpation, identifies a number of preoperatively unsuspected liver neoplasms. Intraoperative ultrasound, however, is the most sensitive method for detection of liver neoplasms and influences the operative management in a substantial number of patients.

Colorectal Neoplasms↗
PubMed1996

A two-year follow-up on the effects of a smoking ban in an inpatient psychiatric service.

The effects of prohibiting cigarette smoking on the behavior of patients on a 25-bed psychiatric inpatient unit were assessed immediately after implementation of a smoking ban and two years later. No major behavioral disruptions were observed after the ban. The number of calls for security assistance, physical assaults, instances of leather restraints and of seclusions, and discharges against medical advice did not increase significantly immediately after the restriction on smoking or two years later. Significantly more verbal assaults and prescribing of p.r.n. medications for anxiety occurred immediately after the ban but not two years later.

Adolescent↗
PubMed1996

Disappearance of DNA HPV in sequential specimens of occult cervical infection in a "normal" population.

OBJECTIVE: The behaviour of occult infection in the uterine cervix was studied over one year in 175 women randomly selected, to determine if the infection persisted, disappeared or if the viral genotype became modified. STUDY DESIGN: An earlier study of the prevalence of HPV cervical infection detected 11 (6.2%) occult infections. Of these the infectious genotype could only be identified in five. One year later the infected women were subjected to further colposcopical examination and molecular hybridization testing. RESULTS: In seven of the 11 cases with cervical occult infection, the DNA HPV genome was found to be completely absent at year-end. Colposcopic and cytological studies remained negative in all women. CONCLUSIONS: The loss of DNA HPV in seven of the 11 previously positive women is probably due to variability in the number of cells that became infected in a situation where small numbers of copies are made. The high proportion of occult infection with uncharacterized viruses supports the view that this type of infection is often due to new genotypes, presently non-classifiable.

Adolescent↗
PubMed1996

Temporal evolution of the corneal curvature in contact lens wearers.

In the present work, we have measured the corneal radii in a group of 126 healthy subjects, studying the temporal evolution of these radii after adaptation to contact lenses of polyhydroxyethyl methacrylate with 55% hydration. We measured the horizontal and vertical radii before adaptation, as well as after 3, 6 and 9 months of wearing contact lenses. The decreases were not significant (P < 0.05) in the corneal radii of these subjects; maximum decreases were reached the day after wearing contact lenses, with subsequent recuperation, such that at 9 months the decreases, though persisting, were minimal.

Adolescent↗
PubMed1995

Diagnosis of Brucella ovis infection of rams with an ELISA using protein G as conjugate.

The complement fixation and gel diffusion tests for Brucella ovis ram epididymitis were compared with an indirect ELISA using antigens from B ovis extracted in hot saline, rough B ovis lipopolysaccharide or a cytosolic fraction of rough B melitensis 115, and commercial anti-IgG (heavy and light chain specificity) or protein G conjugates. None of the antigens and conjugates used in the ELISA gave better results in terms of sensitivity and specificity than the complement fixation or the gel diffusion tests with the sera of 41 rams naturally infected with B ovis, 17 rams inoculated conjunctivally with B ovis and 53 Brucella-free rams. The protein G conjugate significantly reduced the background reactivity of the sera from the Brucella-free rams but did not improve the sensitivity of the ELISA with the anti-IgG conjugate.

Animals↗
PubMed1995

Unsuspected subdural hematoma as a differential diagnosis in elderly patients.

Subdural hematomas are among the most common forms of intracranial hemorrhage encountered in clinical practice and are a surgically remediable cause of dementia. When the symptom presentation is subtle or diffuse, a subdural hematoma can be overlooked. This is especially true among elderly people who may exhibit unrelated, preexisting dementia or delirium. Particularly confusing is that such declines in intellectual capacity can also result from subdural hematoma. It is therefore essential that a thorough physical and neurologic assessment be done on all patients with cognitive deficiencies. This always includes brain imaging. Early recognition of a subdural hematoma is important, given its treatability and potential reversibility. We describe an elderly woman with new-onset cognitive deficit and gait dyspraxia. There was no evidence of trauma. Physical examination was otherwise unremarkable. Initially, she refused evaluation, but once a subdural hematoma was identified by a tomographic scan, a satisfactory outcome followed surgical intervention.

Aged↗
PubMed1995

[The effect of gallopamil and propranolol in patients with ischemic cardiopathy and moderate depression of ventricular function].

BACKGROUND: Calcium channel blockers have been wide and successfully used in the treatment of coronary heart disease. Gallopamil, a metoxylic derivative of verapamil, has many of its properties and so, caution is recommended when given to patients with depressed left ventricular function. Clinical studies about this effect are scarce, and we have assessed it in patients with coronary heart disease and diminished left ventricular function. METHODS: We studied 20 patients in a cross-over, randomized, double-blind study during three weeks active periods with two intercalating washout placebo periods of one week. Patients had history of previous myocardial infarction, positive exercise stress test and ejection fraction ranging from 30% to 50% by echocardiography. RESULTS: There were no significant differences between each drug and corresponding placebo on either systolic or diastolic function. When we compared both drugs, patients showed a milder increase in area under E after propranolol than after gallopamil (p < 0.008). Clinical episodes of cardiac failure were not reported, and ejection fraction did not change. CONCLUSIONS: Both gallopamil and propranolol can be used in patients with coronary heart disease and moderately depressed left ventricular ejection fraction.

Adrenergic beta-Antagonists↗
PubMed1994

Expression of genes and processing of enzymes for the biosynthesis of penicillins and cephalosporins.

The genes pcbAB, pcbC and penDE encoding the enzymes (alpha-aminoadipyl-cysteinyl-valine synthetase, isopenicillin N synthase and isopenicillin N acyltransferase, respectively) involved in the biosynthesis of penicillin have been cloned from Penicillin chrysogenum and Aspergillus nidulans. They are clustered in chromosome I (10.4 Mb) of P. chrysogenum, in chromosome II of Penicillium notatum (9.6 Mb) and in chromosome VI (3.0 Mb) of A. nidulans. Each gene is expressed as a single transcript from separate promoters. Enzyme regulation studies and gene expression analysis have provided useful information to understand the control of genes involved in penicillin biosynthesis. The enzyme isopenicillin N acyltransferase encoded by the penDE gene is synthesized as a 40 kDa protein that is (self)processed into two subunits of 29 and 11 kDa. Both subunits appear to be required for acyl-CoA 6-APA acyltransferase activity. The isopenicillin N acyltransferase was shown to be located in microbodies, whereas the isopenicillin N synthase has been reported to be present in vesicles of the Golgi body and in the cell wall. A mutant in the carboxyl-terminal region of the isopenicillin N acyltransferase lacking the three final amino acids of the enzymes was not properly located in the microbodies and failed to synthesize penicillin in vivo. In C. acremonium the genes involved in cephalosporin biosynthesis are separated in at least two clusters. Cluster I (pcbAB-pcbC) encodes the first two enzymes (alpha-aminoadipyl-cysteinyl) valine synthetase and isopenicillin N synthase) of the cephalosporin pathway which are very similar to those involved in penicillin biosynthesis. Cluster II (cefEF-cefG), encodes the last three enzymatic activities (deacetoxycephalosporin C synthetase/hydroxylase and deacetylcephalosporin C acetyltransferase) of the cephalosporin pathway. It is unknown, at this time, if the cefD gene encoding isopenicillin epimerase is linked to any of these two clusters. Methionine stimulates cephalosporin biosynthesis in cultures of three different strains of A. chrysogenum. Methionine increases the levels of enzymes (isopenicillin N synthase and deacetylcephalosporin C acetyltransferase) expressed from genes (pcbC and cefG respectively) which are separated in the two different clusters of cephalosporin biosynthesis genes. This result suggests that both clusters of genes have regulatory elements which are activated by methionine. Methionine-supplemented cells showed higher levels of transcripts of the pcbAB, pcbC, cefEF genes and to a lesser extent of cefG than cells grown in absence of methionine. The levels of the cefG transcript were very low as compared to those of pcbAB, pcbC and cefEF.(ABSTRACT TRUNCATED AT 400 WORDS)

Acyltransferases↗
PubMed1994

Current understanding of severe preeclampsia, pregnancy-associated hemolytic uremic syndrome, thrombotic thrombocytopenic purpura, hemolysis, elevated liver enzymes, and low platelet syndrome, and postpartum acute renal failure: different clinical syndromes or just different names?

Endothelial cell injury, with subsequent vasospasm, platelet activation, unbalanced prostacyclin-thromboxane ratio, and decreased release of endothelium-derived relaxing factor, play a central role in the pathogenesis of several disorders such as preeclampsia, hemolysis, elevated liver enzymes, and low platelet syndrome, thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, acute fatty liver of pregnancy, and acute renal failure. It is possible that all these diseases are part of a spectrum of the same illness. Although the cause remains unknown, the pathophysiology of these diseases is important for an early diagnosis. Differential diagnosis is often difficult due to the overlap of these syndromes. The purpose of this review is to clarify the differences and similarities among these pregnancy-related complications.

Acute Kidney Injury↗
PubMed1994

Molecular characterization of three loss-of-function mutations in the isopenicillin N-acyltransferase gene (penDE) of Penicillium chrysogenum.

Five mutants of Penicillium chrysogenum blocked in penicillin biosynthesis (npe) which are deficient in isopenicillin N-acyltransferase were isolated previously. Three of these mutants, npe6, npe7, and npe8, have been characterized at the molecular level and compared with npe10, a deletion mutant. Transcripts of normal size (1.15 kb) of the penDE genes, which encode isopenicillin N-acyltransferase, and also of the pcbAB (11.5 kb) and pcbC (1.1 kb) genes were observed in all mutants except for the npe10 mutant. Immunoblotting studies using antibodies against isopenicillin N-acyltransferase showed that all mutants (except npe10) formed the 40-kDa (unprocessed) protein and the 29-kDa subunit of the isopenicillin N-acyltransferase. The 11-kDa subunit could not be observed in the immunoblots. The mutant penDE genes of strains npe6, npe7, and npe8 were cloned and sequenced. These three strains showed a mutation in the penDE genes which results in a single amino acid change in each modified isopenicillin N-acyltransferase. The mutation in npe6 resulted in a change of Gly-150 to Val, whereas the mutation in both npe7 and npe8 introduced a change of Glu-258 to Lys. Replacement of the Val-150 and Lys-258 mutations by constructing hybrid isopenicillin N-acyltransferase molecules led to the recovery of the isopenicillin N-acyltransferase activity. The mutations in npe6, npe7, and npe8 do not affect the ability of the 40-kDa isopenicillin N-acyltransferase to be processed into the component subunits.

Acyltransferases↗
PubMed1994

Exogenous methionine increases levels of mRNAs transcribed from pcbAB, pcbC, and cefEF genes, encoding enzymes of the cephalosporin biosynthetic pathway, in Acremonium chrysogenum.

Methionine stimulated cephalosporin production in cultures of three different strains of Acremonium chrysogenum when added either at inoculation time or at 72 h to cells grown previously in the absence of methionine. When methionine was added at 72 h, the stimulation of cephalosporin biosynthesis was observed only 12 h later and required de novo protein synthesis. Methionine increased the levels of enzymes (isopenicillin N synthase and deacetylcephalosporin C acetyltransferase) expressed from genes (pcbC and cefG, respectively) located in the two clusters of cephalosporin biosynthesis genes in the wild-type A. chrysogenum strain and also in the two improved strains, CW19 and C10. Methionine-supplemented cells showed higher levels of transcripts of the four known genes (pcbAB, pcbC, cefEF and, to a slight extent, cefG) of the cephalosporin biosynthetic pathway than cells grown in the absence of methionine. The levels of the cefG transcript were much lower than those of the pcbAB, pcbC, and cefEF transcripts. The induction by methionine of transcription of the four cephalosporin biosynthesis genes and the known effect of this amino acid on the differentiation of A. chrysogenum indicate that methionine exerts a pleiotropic effect that coordinately regulates cephalosporin biosynthesis and differentiation.

Acetyltransferases↗
PubMed1994

Evaluation of allergic and serological tests for diagnosing Brucella melitensis infection in sheep.

A total of 291 unvaccinated sheep from Brucella melitenesis-infected flocks were examined for delayed-type hypersensitivity (DTH) responses with Brucellergene commercial allergen and with cold saline extract and cytosol from rough B. melitensis 115, and their sera were tested in the rose bengal test (RBT), complement fixation test (CFT), and enzyme-linked immunosorbent assay (ELISA) with lipopolysaccharide. DTH reactions were maximal after 72 h, with no intensity differences among allergens, inoculation sites (eyelid and tail), and doses tested. There were no differences in the results recorded by visual inspection and palpation of inoculation sites, by measuring skin thickness with a caliper, or by microscopic examination of samples taken at necropsy. Six days after DTH testing, energy was observed in 100% of the animals, and 100% reactivity was recovered only after 24 days. All animals were necropsied, and thorough bacteriological searches were performed. The sensitivities found with the 140 animals from which B. melitensis was isolated were ELISA, 100%; DTH, 97.1%; RBT, 92.1%; and CFT, 88.6%. Those results put into question the value of RBT and CFT as screening and confirmatory tests for sheep brucellosis and at least indicate that their standardization should be modified. For 151 tested sheep from which B. melitensis was not isolated, the percentages of positive animals were ELISA, 100%; DTH, 94.0%; RBT, 57.6%; and CFT, 53.6%. All tests were negative for 100 tested sheep from Brucella-free flocks. The different results of bacteriological and immunological tests suggest the usefulness of developing indirect tests able to distinguish truly infected animals from those that have developed an immunological response.

Allergens↗