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Biomedical subjects

D Rodriguez

Publications and source records attributed to D Rodriguez.

At least 91 records · Page 5Linked to original sources
PubMed1994

Adaptation of signal transduction in brain.

Cell culture models were used to study the effects of long-term ethanol exposure on neuronal cells. Effects on phospholipase C and phospholipase D mediated signal transduction were investigated by assaying receptor-binding, G protein function, activities of lipases, formation of second messengers and c-fos mRNA. The signal transduction cascades displayed abnormal activities from 2 to 7 days of exposure which differed from the acute effects. Phosphatidylethanol formed by phospholipase D is an abnormal lipid that may harmfully affect nerve cell function.

Acclimatization↗
PubMed1994

Aberrant splicing of exon 6 in the pyruvate dehydrogenase-E1 alpha mRNA linked to a silent mutation in a large family with Leigh's encephalomyelopathy.

Pyruvate dehydrogenase (PDH)-E1 alpha deficiency has recently been studied at the molecular-genetic level. The gene is situated on the X chromosome. We report on an unusual mutation in a familial E1 alpha deficiency. In fibroblasts, PDH deficiency was diagnosed in a young infant presenting with Leigh's encephalomyelopathy and in a maternal nephew with episodes of "malaises." In the two affected children as well as their mothers we found a silent mutation in exon 6 of the PDH-E1 alpha and an aberrant splicing of exon 6 in some of the cDNA clones. This case emphasizes the need for both genomic and cDNA analysis in cases where a PDH-E1 alpha deficiency is strongly suspected.

Base Sequence↗
PubMed1994

Promoting quality mental health care delivery with critical path care plans.

1. Mental Health providers are under increasing pressure to provide objective, individualized care that produces outcomes that may be measured against accepted clinical standards. 2. Clinicians may now track patient responses throughout a continuum of treatment in varying locations by using a customized critical path/treatment plan format. 3. Care delivery is documented by superimposing actual occurrences over desired ones on a critical pathway.

Continuity of Patient Care↗
PubMed1993

A proposal for the establishment of the National Center for Phytogenetic Resource Conservation in the Venezuelan Republic.

The conservation of biodiversity, a valuable natural resource, is considered essential. In the face of continued threats to this resource the establishment of a National Center for Phytogenetic Resource Conservation in Venezuela is proposed. The proposed center would have the following main objectives: inventory of resources, establishment of a plant gene bank, basic ecological research, promotion of cultivation of useful but endangered species, promotion of national and international information-exchange, and protection of natural habitats. The organizational structure of the proposed center is outlined.

Conservation of Natural Resources↗
PubMed1993

Priming with recombinant influenza virus followed by administration of recombinant vaccinia virus induces CD8+ T-cell-mediated protective immunity against malaria.

Live vectors expressing foreign antigens have been used to induce immunity against several pathogens. However, for the virulent rodent malaria parasite Plasmodium yoelii, the use of recombinant vaccinia virus, pseudorabies virus, or Salmonella, expressing the circumsporozoite protein of this parasite, failed to induce protection. We generated a recombinant influenza virus expressing an epitope from the circumsporozoite protein of P. yoelii known to be recognized by CD8+ T cells and demonstrated that this vector induced class I major histocompatibility complex-restricted cytotoxic T cells against this foreign epitope. Immunization of mice with this recombinant influenza virus, followed by a recombinant vaccinia virus expressing the entire circumsporozoite protein, induced protective immunity against sporozoite-induced malaria. The sequence of immunization appears to be crucial, since a primer injection with recombinant vaccinia virus, followed by a booster injection with recombinant influenza virus, failed to induce protection. The protection induced by immunization with these recombinant viruses is mostly mediated by CD8+ T cells, as treatment of mice with anti-CD8 monoclonal antibody abolishes the anti-malarial immunity. The use of different live vectors for primer and booster injections has a synergistic effect on the immune response and might represent an effective general strategy for eliciting protective immune responses to key antigens of microbial pathogens.

Amino Acid Sequence↗
PubMed1993

Hemodialysis changes the QRS amplitude in the electrocardiogram.

We studied eight patients to determine whether changes occur in the QRS amplitude when these patients are submitted to hemodialysis. The following variables were assessed before and after each (N = 28) hemodialysis session: (1) plasma sodium and potassium concentrations, (2) QRS amplitude, (3) the heart rate and its variability, (4) ventricular volumes, ventricular mass, ejection fraction and circumferential fiber shortening, (5) arterial pressure and end systolic stress, and (6) body weight. QRS amplitude was computed as the algebraic sum of the positive and negative waves of each QRS complex of the electrocardiogram. QRS amplitude changes were compared to body weight, ventricular volumes, ventricular mass, ejection fraction, circumferential fiber shortening, plasma potassium and sodium concentrations, arterial pressure, end systolic stress, heart rate, and R-R variability. After the hemodialysis sessions we found a significant increase (P = 0.0006) in QRS amplitude and a significant decrease in body weight (P = 0.0001), end diastolic volume (P = 0.043), plasma potassium concentration (P = 0.000001), end systolic stress (P = 0.025) and systolic arterial pressure (P = 0.023). Hemodialysis did not produce significant changes in the other variables. The statistical analyses performed did not show any significant influence of any of the measured variables on the QRS amplitude change. The QRS amplitude increases after hemodialysis but the cause of this increase is still unclear.

Arrhythmias, Cardiac↗
PubMed1993

Recombinant vaccinia viruses expressing GP46/M-2 protect against Leishmania infection.

Leishmania is a genus of parasitic protozoa capable of causing a spectrum of human diseases. The GP46/M-2 membrane glycoprotein has been demonstrated in a murine model system to elicit a protective immune response against infection with Leishmania amazonensis; in highly susceptible BALB/c mice, immunization leads to significant protection against infection. In the present study, for induction of long-term immunological effects, two recombinant vaccinia viruses, derived from the wild type and attenuated variant 48-7 and expressing the GP46/M-2 protein, were constructed; to ensure safety, we used the attenuated vaccinia virus mutant (48-7) as a live vector. Susceptible BALB/c mice immunized with either GP46/M-2-recombinant vaccinia virus were significantly protected against infection with L. amazonensis; 45 to 76% of the animals were completely protected (sterile) against a challenge inoculum of 10(3) infective organisms. The protectively immunized animals demonstrated T- and B-cell-dependent immunological responses; both lymphokine responses as well as antibody responses and long-term memory are indicative of T-cell activation. This first report of the use of a recombinant vaccinia virus to induce protection against a Leishmania infection indicates that recombinant vaccinia viruses should be of value in the design of a safe and effective vaccine against this parasitic disease.

Animals↗
PubMed1993

The vaccinia virus 14-kilodalton fusion protein forms a stable complex with the processed protein encoded by the vaccinia virus A17L gene.

The mechanism by which the 14-kDa fusion protein of vaccinia virus (VV) is anchored in the envelope of intracellular naked virions (INV) is not understood. In this investigation, we demonstrate that the 14-kDa protein interacts with another virus protein with an apparent molecular mass of 21 kDa. Microsequence analysis of the N terminus of the 21-kDa protein revealed that this protein is encoded by the VV A17L gene. The 21-kDa protein is processed from a 23-kDa precursor, by cleavage at amino acid position 16, at the consensus motif Ala-Gly-Ala, previously identified as a cleavage site for several VV structural proteins. The 21-kDa protein contains two large internal hydrophobic domains characteristic of membrane proteins. Pulse-chase analysis showed that within 1 h after synthesis, the 14-kDa protein forms a stable complex with the 21-kDa protein. Formation of the complex was not inhibited by rifampin, indicating that the interaction between these two proteins occurs prior to virion morphogenesis. Immunoprecipitation analysis of disrupted virions showed the presence of the 21-kDa protein in the viral particle. Release of the 14-kDa-21-kDa protein complex from INV required treatment with the nonionic detergent Nonidet P-40 and a reducing agent. The protein complex consisted of 14-kDa trimers and of 21-kDa dimers. Since the 14-kDa fusion protein lacks a signal sequence and a large hydrophobic domain characteristic of membrane proteins, our findings suggest that the 21-kDa protein serves to anchor the 14-kDa protein to the envelope of INV.

Amino Acid Sequence↗
PubMed1993

Immunization against porcine cysticercosis in an endemic area in Mexico: a field and laboratory study.

An antigenic extract from Taenia solium metacestodes was evaluated for immunogenicity in pig populations from a large area of endemic porcine cysticercosis in the State of Guerrero, Mexico. A total of 3,295 pigs from 18 villages were immunized with a single dose of 250 micrograms of protein administered intramuscularly. Systematic immunization was also performed on pigs (1,076 immunizations) from two of the villages with the highest percentages of cysticercosis. A year after immunization, porcine cysticercosis decreased from 4.8% and 5.4% to 0%. Immunity against the T. solium metacestode was estimated in vitro by measurements of 3H-thymidine uptake and inhibition of leukocyte migration. Peripheral blood lymphocytes from immunized cysticercotic (pigs that had cysticercosis prior to immunization), cysticercotic immunized (pigs that acquired cysticercosis after immunization), and normal control pigs incorporated 3H-thymidine better than lymphocytes from cysticercotic pigs when stimulated with concanavalin A. A significant inhibition in the leukocyte migration inhibition test was also found in leukocytes from immunized cysticercotic pigs (P < 0.01). Histopathologic studies revealed granuloma formation surrounding the metacestodes of the immunized cysticercotic and cysticercotic immunized pigs. These metacestodes exhibited several stages of destruction. Large numbers of eosinophils were frequently observed in a close association with the degeneration and destruction of parasites. Metacestodes in control cysticercotic pigs were intact and surrounded by a minor inflammatory reaction. Finally, the rate of in vitro evagination of scolices was high in metacestodes obtained from cysticercotic pigs and low or absent in those from immunized pigs (P < 0.01).

Animals↗
PubMed1992

Detection of a soluble antigen defined by monoclonal antibody 83D4 in serous effusions associated with breast carcinoma.

Monoclonal antibody (MoAb) 83D4 was generated by immunization with cell suspensions obtained from sections of formol-fixed paraffin embedded human breast cancer. It recognized an antigen expressed in breast carcinomas but not in normal breast tissue. Pleural and ascitic fluids from 66 patients were studied by an 83D4 heterologous sandwich radioimmunoassay (SRIA) using solid-phase immobilized wheat germ agglutinin to detect the 83D4 soluble antigen. Using a cutoff level of 5 units/ml of 83D4 antigen, higher values were found in 22 of 27 breast cancer-associated effusions (mean = 10.72 +/- 6.80 units/ml). The 20 nonmalignant effusion fluids tested showed lower values (mean = 1.16 +/- 1.49 units/ml, P less than 0.001). The antigen was undetectable or present in low levels in effusions from patients with hematologic malignancies. When SRIA results were compared with conventional cytologic diagnosis in breast-cancer effusions, elevated levels of 83D4 soluble antigen were found in all patients (8 of 8) in whom malignant cells had been detected, in 4 of 8 patients with the diagnosis of "suspected malignancy," and in 10 of 11 patients with negative cytologic findings. Using an immunoglucosidase method on cell smears of various origins, MoAb 83D4 stained metastatic cells of breast and ovary carcinomas but did not reactive with mesothelial cells and other normal or malignant cell types. These results suggest that quantitation of the 83D4 soluble antigen may be used to improve the diagnosis of cancer in serous effusions.

Antibodies, Monoclonal↗
PubMed1992

Insertional inactivation of the vaccinia virus 32-kilodalton gene is associated with attenuation in mice and reduction of viral gene expression in polarized epithelial cells.

The mechanism of poxvirus attachment to cells is poorly understood. We have identified a 32-kDa envelope protein of vaccinia virus which binds to the surface of cultured cells. This binding is specific and selective (J.-S. Maa, J. F. Rodriguez, and M. Esteban, J. Biol. Chem. 265:22174-22180, 1990; C. Lai, S. Gong, and M. Esteban, J. Virol. 65:499-504, 1991). In this investigation, we studied the effect of inactivating the 32-kDa gene (32K gene) on the biology of vaccinia virus. We show that inactivation of the 32K gene decreases by 80% the mortality of mice infected with 32K- vaccinia virus. This reduction in mortality correlates with diminished viral gene expression in target tissues. In highly polarized epithelial cells, viral gene expression of 32K- virus was reduced (50 to 60%) at both the apical and basolateral surfaces in comparison with a 32K+ virus. Restriction of virus gene expression in polarized cell surfaces occurs for both intracellular and extracellular forms of infectious 32K- vaccinia virus. The two infectious forms of vaccinia virus 32K+ infect polarized cells preferentially by the basolateral surface. Our findings provide evidence of the importance of the 32-kDa protein in viral pathogenesis.

Animals↗
PubMed1992

Differences in macrophage stimulation and leukocyte accumulation in response to intraperitoneal administration of glucose/mannose-binding plant lectins.

Peritoneal macrophage stimulation (rapid spreading on glass surface and hydrogen peroxide production) and inflammatory reaction (leukocyte accumulation) obtained in C3H/HeJ mice at 8 weeks of age, after a single ip injection of 10 micrograms concanavalin A (Con A), a lectin extracted from Canavalia ensiformis, were compared with those obtained with two other glucose/mannose-binding lectins extracted from Canavalia brasiliensis (Con Br) and Dioclea grandiflora (DGL). All lectins enhanced macrophage spreading 3- to 4-fold at 24-72 h compared to control. Stimulation of hydrogen peroxide release by Con A, Con Br and DGL lasted 1, 2 and 3 days, respectively. Leukocyte cell influx at 24-72 h after lectin injection consisted mainly of mononuclear cells. Con A induced a moderate increase in the total number of peritoneal cells, whereas administration of Con Br or DGL increased the number of peritoneal cells 2- to 3-fold. The results indicate that DGL and Con Br have more pronounced effects on macrophage stimulation and inflammatory reactions than Con A.

Animals↗
PubMed1992

[Creutzfeldt-Jakob disease in 4 children treated with growth hormone].

Creutzfeldt-Jakob disease was diagnosed in four growth hormone recipients at the age of 10, 11, 18 and 19 years. To our knowledge, the two first cases are the first instances of Creutzfeldt-Jakob disease recorded in children. Three of them were still being treated with synthetic hormone at the onset of the disease. Neurological disorders: ataxia and diplopia, appeared first, dementia and myoclonus appeared later. Eighteen cases of Creutzfeldt-Jakob disease in growth hormone recipients are now recorded, and the present risk of Creutzfeldt-Jakob disease in pituitary growth recipients is estimated to be 1/300. Because of the long incubation period, new cases are to be feared. Other causes of iatrogenic Creutzfeldt-Jakob disease are reviewed. These facts incite to consider carefully using products of human origin in human therapy. The interactions between growth hormone, prion and host's genomic make-up are still not clear.

Adolescent↗
PubMed1991

Clinical and radiographic response of fourth ventricle cysticercosis to praziquantel therapy.

A case of fourth ventricle cysticercosis treated with praziquantel is presented. The disappearance of the lesion six months after the treatment was demonstrated by CT scan. A review of the literature indicates that this is a very exceptional result, because with recently intraventricular cysticercosis was considered to be non-responsive to praziquantel treatment, making surgery necessary.

Calcinosis↗
PubMed1991

Interferon treatment inhibits early events in vaccinia virus gene expression in infected mice.

We have analyzed the role of exogenous administration of mouse interferon (IFN alpha + beta) on the replication of vaccinia virus in peritoneal cells and in the spleen of Balb/c mice. Mice were pretreated for 16 hr with IFN and then infected with a vaccinia virus recombinant expressing luciferase under an early or late virus promoter, and the enzyme activity was measured in the course of virus infection. A dose of IFN as low as 10(3) units/mouse abolished the appearance of luciferase activity in cells of the peritoneal cavity and in spleen cells. The IFN-mediated inhibition of luciferase activity was observed even when mice were infected 4 days after the administration of IFN. The IFN-treated animals were considered free of virus since neither luciferase nor viral proteins were detected in target cells several days after virus infection. Despite a severe IFN-mediated inhibition of luciferase activity, the appearance of luciferase on mRNA levels was not inhibited 6 hr after virus infection. Our finding revealed that replication of vaccinia virus in Balb/c mice is exquisitively sensitive to inhibition by IFN and that this effect occurs at early times postinfection, most likely as a result of a translational block.

Animals↗
PubMed1991

Structural properties of HIV-1 Env fused with the 14-kDa vaccinia virus envelope protein.

To gain insights into the structure-function relationship of the envelope (env) glycoprotein of the human immunodeficiency virus type 1 (HIV-1) we have generated a vaccinia virus (VV) recombinant (VV-14kENV) that expresses a fusion protein (14k-env) consisting of the VV 14-kDa envelope protein (110 amino acids) fused at the C-terminus with HIV-1 env protein (816 amino acids). The 14k-env protein displayed unique structural properties in virus-infected cells. This protein was recognized by 14 kDa-specific antisera as well as HIV-1 env antisera. It was not cleaved during virus infection of cultured cells of various origins, it was stable, it was not released to the medium, and it was not incorporated into virions. Instead of a predicted 174-kDa protein, two proteins of about 110 and 100 kDa were observed. The size reduction of the fusion protein was due to limited glycosylation (110 kDa) and formation of unglycosylated protein (100 kDa). The 14k-env protein formed oligomeric structures and was exposed on the cell surface after virus infection. When mice were inoculated with the recombinant virus that expresses the 14K-env fusion protein, humoral immune response against gp160 was observed. Our findings suggest that 14k-env protein might display novel immunogenic properties.

Animals↗
PubMed1991

Vaccinia virus preferentially enters polarized epithelial cells through the basolateral surface.

The uptake of vaccinia virus in polarized epithelial cells was studied to determine whether the site of entry was confined to either the apical or the basolateral membrane. Virus infection was monitored with a recombinant vaccinia virus carrying the luciferase reporter gene. Using cell lines MDCK and MDCK-D11, a clonal line with high transepithelial electrical resistance, we determined that vaccinia virus preferentially enters through the basolateral membrane. The possibility that there is a polarized cell surface distribution of vaccinia virus receptors which may be involved in systemic poxvirus infections is discussed.

Animals↗