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Biomedical subjects

J de la Fuente

Publications and source records attributed to J de la Fuente.

11 recordsLinked to original sources
PubMed1992

High level expression of streptokinase in Escherichia coli.

Streptokinase (SK), which activates human plasminogen by promoting its conversion to plasmin, is normally obtained from beta-hemolytic streptococci. Treatment with SK is an effective therapy for improving survival and preserving left ventricular function after coronary thrombosis. We report the cloning, expression in E. coli to levels of 25% of the total cell protein, and characterization of a novel SK (SKC-2) gene, the product of which is functionally equivalent to the naturally-derived protein. The availability of a recombinant streptokinase (rSK) in high yield and purity offers a potentially attractive alternative source of this important therapeutic agent.

Amino Acid Sequence↗
PubMed1992

[Tuberculous meningitis in patients without HIV infection. Presentation of 21 cases].

BACKGROUND: Tuberculous meningitis accounts for 5% to 12% of all extrapulmonary tuberculosis cases in western-hemisphere population non infected by HIV virus, and carries a high mortality rate. METHODS: We analyze retrospectively 21 patients with tuberculous meningitis in HIV negative patients seen from 1975 to 1989, with emphasis on clinical, laboratory and therapeutic features. RESULTS: In 48% of cases there were not typical meningeal signs, and 61% of patients showed neurological focal signs and/or seizures. CSF examination revealed a clear fluid with high cell counts (mostly lymphocytes), high protein and low sugar levels in 67% of cases. However, the microbiologic examination had a low yield of diagnosis (33%). The clinical course is prolonged, and treatment is usually delayed. Morbidity and mortality were high (34% and 10% of cases). In this study, the use of steroids did not show a significant reduction in mortality nor in neurological sequelae. CONCLUSION: Tuberculous meningitis in HIV negative patients is a chronic infection, without meningeal signs in most cases and linked to a high rate of neurological defects. The microbiologic tests have low yield of diagnosis. Steroid drugs seem to be indicated only if there are additional complications.

Adolescent↗
PubMed1992

Purification of streptokinase by affinity chromatography on immobilized acylated human plasminogen.

Streptokinase is an extracellular protein produced by several strains of streptococci. It functions in the species-specific conversion of plasminogen to plasmin. In this paper we describe the purification of streptokinase by affinity chromatography on human plasminogen acylated with p'-nitrophenyl p-guanidinobenzoate. The acylated and non-acylated plasminogen and plasmin were coupled to cyanogen bromide-activated Sepharose 4B and evaluated for streptokinase purification. These results show that a homogeneous preparation of streptokinase with high specific activity and high yield can be obtained using acylated plasminogen. This method permits the binding of one milligram of streptokinase per milliliter of swollen gel.

Acylation↗
PubMed1991

Cloning of coliphage-T4 gene pseT and high-level synthesis of polynucleotide kinase in Escherichia coli.

The gene, pseT, of coliphage T4 which encodes polynucleotide kinase (PNK) was cloned directly into an expression plasmid using the polymerase chain reaction. When placed under the control of the trp promoter, the pse T gene can be maintained stably in Escherichia coli and yields high levels of the enzyme upon induction. The system described facilitates purification and provides very high yields of PNK.

Base Sequence↗
PubMed1991

[Headache following spinal puncture: treatment with epidural blood patch in a 7-year-old patient].

Lumbar puncture is frequently used for diagnostic and therapeutic purposes in children. Theoretically, this group of patients should have high rates of post lumbar puncture headache. However, the scant available literature points to a surprisingly low incidence and an apparently mild course. We present a 7 year-old patient with a severe post lumbar puncture headache successfully treated with an epidural blood patch. To our knowledge, this has not been reported in children younger than 10 years. We believe this procedure should be considered in pediatric patients with post lumbar puncture headache.

Blood Patch, Epidural↗
PubMed1991

[Lupus induced by quinidine].

The case is described of a 34 year old female who suffered quinidine induced lupus, which appeared 14 months after the administration of the drug, and it was necessary to substitute it. This secondary effect o quinidine, which is rarely described, can go unnoticed if it is no kept in mind. The diagnostic criteria for drug induced lupus ar discussed and the clinical and analytical manifestations of 27 cases o quinidine induced lupus described in the literature are reviewed.

Adult↗
PubMed1990

Different pathways mediate virus inducibility of the human IFN-alpha 1 and IFN-beta genes.

Multimerization of GAAANN generates sequences frequent in virus-inducible promoters. We distinguished different types of (GAAANN)4 sequences mediating virus inducibility. Type I (NN = GT, GC, CT, or CC) responds to IFNs and to IRF-1 and causes silencing. Type II (NN = TG) and type III (NN = CG) neither silence nor respond to IRF-1 or IFN. Type III mediates constitutive transcription and binds the constitutive IEFga factor, whereas type II binds the novel "TG protein". IFN-beta and IFN-alpha 1 promoters contain different response elements: The former has a type I-like sequence (PRDI) and an NF-kappa B-binding sequence (PRDII); the latter has a type II-like "TG sequence" and possibly additional elements but does not bind NF-kappa B. Type I, type II, and NF-kappa B elements represent three distinct terminal pathways mediating virus induction.

Animals↗
PubMed1987

Reversible silencing of enhancers by sequences derived from the human IFN-alpha promoter.

The virus-responsive element of the IFN-alpha 1 promoter, VRE(IFN alpha), comprises two imperfect 19 bp repeats, repA and repB. VRE(IFN alpha), tetrameric repA, and tetrameric GAAAGT (a subsequence of repB) or tetrameric AAGTGA conferred inducibility on a reporter gene when placed upstream of a complete or truncated promoter. Induced transcription was weak with a minimal promoter (TATA box only), but was strongly stimulated by the SV40 enhancer placed immediately upstream of the inducible element. Surprisingly, under noninduced conditions, tetrameric repA, GAAAGT, and AAGTGA (but not VRE(IFN alpha)) completely silenced enhancement of constitutive transcription by the SV40 72 bp repeat when interposed between the latter and the TATA box; silencing was fully abrogated by induction.

Animals↗
PubMed1984

Visible chemiluminescence induced by t-butyl hydroperoxide in red blood cell suspensions.

Red blood cells from Wistar rats were exposed to milimolar concentrations of t-butyl hydroperoxide. Extensive hemoglobin oxidation (methemoglobin formation), t-butyl hydroperoxide cleavage (t-butanol formation) and peroxidation (measured by oxygen consumption and thiobarbituric acid reactive substances) was observed. Significant chemiluminescence was emitted by the system. Hemoglobin oxidation and t-butanol production were independent of oxygen pressure and free radical scavengers, however, luminescence was enhanced as oxygen pressure increased and it was reduced by addition of free radical scavengers. The spectral distribution of the light emitted suggests that the luminescence detected is not due to singlet oxygen dimol emission. The results are in agreement with a lipid peroxidative mechanism initiated by t-butoxy radicals produced in the interaction of hemoglobin and t-butyl hydroperoxide.

Animals↗