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Biomedical subjects

E Rivera

Publications and source records attributed to E Rivera.

At least 19 recordsLinked to original sources
PubMed1992

[Thoracic radiography in Pneumocystis carinii pneumonia in AIDS patients. Presentation forms and clinical course].

BACKGROUND: We intend to determine the frequency of the different radiographic findings of Pneumocystis carinii pneumonia in patients with AIDS. METHODS: We retrospectively review the chest roentgenograms of 30 patients at admission to the hospital (group I [n = 30]), at follow-up (group II [n = 30]) and after clinical recovery (group III [n = 15]). RESULTS: Diffuse bilateral interstitial disease was the most frequent radiographic finding at admission (76.6%) and at follow-up (60%). Atypical radiographic findings were: normal chest radiograph (group I [n = 3]), nodules (group I [n = 2], group II [n = 2], group III [n = 1]), thin wall cysts (group II [n = 1], group III [n = 1]), cavitated lesion (group II [n = 1], group III [n = 1]), pneumothorax (group II [n = 2], group III [n = 1]), pleural effusion (group III [n = 2]), asymmetrical distribution of the pulmonary lesion (group I [n = 2], group II [n = 3]) and predominant upper lobe involvement (group II [n = 1], group III [n = 1]). The atypical findings were greater during follow-up (group II [n = 33.3%], group III (46.6%) than at admission (group I [n = 23.4%]). CONCLUSIONS: It is important to know the frequency and multiplicity of the radiographic findings of Pneumocystis carinii pneumonia in order to establish the diagnosis and differentiation from other infectious diseases or other causes of pulmonary disease in patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Experimental evaluation of antitoxic protective effect of new cholera vaccines in mice.

Intraperitoneal immunization of mice and subsequent challenge with purified cholera toxin (CT) were employed to evaluate the anti-cholera toxin protective effect of two new oral cholera vaccines, live CVD 103-HgR and killed B subunit-whole cell (BS-WC). CVD 103-HgR vaccine demonstrated 100% protection of mice against 2.25 LD50 and 70% against 3 LD50 of CT. Mice immunized with BS-WC vaccine were protected against 2.25 and 3 LD50 of CT in 88 and 62% of cases, respectively. All three killed parenteral vaccines failed to protect against CT. We suggest this mouse system for preliminary evaluation of the antitoxic protective activity of cholera vaccines.

Animals↗
PubMed1992

Patterns of contrast enhancement of tuberculous lymph nodes demonstrated by computed tomography.

The purpose of this study was to evaluate the contrast-enhanced CT characteristics of pathologic thoraco-abdominal lymph nodes in 38 patients infected with Mycobacterium tuberculosis (30 without AIDS and eight with AIDS). Unenhanced scans of chest, abdomen and pelvis were also done in all cases. The CT attenuation values and the enhancement characteristics of the largest node or group of lymph nodes were evaluated in a dynamic sequence over a period of 10 min. On unenhanced CT the nodes were of low attenuation (less than 30 HU) in 18 cases and of soft tissue attenuation (greater than 35 HU) in 20 cases. Four post-contrast patterns of enhancement were found: (i) peripheral rim enhancement (n = 22); (ii) inhomogeneous enhancement (n = 8); (iii) homogeneous enhancement (n = 6); and (iv) homogeneous nonenhancing nodes (n = 2). Increase of attenuation and obliteration of perinodal fat was found in 13 cases, most of them with the peripheral rim enhancement pattern. Seven cases had a combination of enhancing patterns in the same nodal group. The central enhancement was usually moderate (mean, 30 HU) but was marked (greater than 60 HU) in three patients with the homogeneous enhancement pattern. Neither the nodal attenuation values nor the patterns of enhancement are characteristic of tuberculosis, however adenopathy showing peripheral rim-enhancement with relative low attenuation centres can suggest a diagnosis of tuberculosis in the appropriate clinical setting.

Adolescent↗
PubMed1992

Bacillary haemoglobinuria diagnosis by the peroxidase-antiperoxidase (PAP) technique.

A peroxidase-antiperoxidase (PAP) technique was used to diagnose bacillary haemoglobinuria in formalin-fixed, paraffin-embedded liver tissues of cattle. The PAP method revealed Clostridium haemolyticum in the zone of liver necrosis characteristic of the disease and also in culture smears of this microorganism, but C. novyi type B, C. chauvoei, C. septicum and C. perfringens types B and C remained unstained by the PAP reaction. The PAP technique performed provides a specific, simple and rapid method to diagnose bacillary haemoglobinuria.

Animals↗
PubMed1991

Structure of the binuclear metal-binding site in the GAL4 transcription factor.

The GAL4 transcription factor from yeast contains within its N-terminal DNA-binding domain an amino acid sequence containing six cysteine residues, C11-X2-C14-X6-C21-X6-C28-X2-C31-X6-C38. The six Cys residues will form a binuclear metal cluster with either Zn(II) or Cd(II) in which two of the -S- donors are bridging ligands between the two metal ions. Binding of Zn(II) or Cd(II) to the GAL4 DNA-binding domain is essential to induce the conformation of GAL4 required for the protein to recognize the specific DNA sequence, UASG, to which GAL4 binds. Evidence for the presence of the binuclear cluster has come from 113Cd NMR and 2D 1H-113Cd heteronuclear NMR studies of the cloned DNA-binding domain of GAL4 consisting of the N-terminal 62 residues, GAL4(62*) [Pan and Coleman (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 2077]. Cd(II) binding to the GAL4 DNA is highly cooperative, thus the Cd2Cys6 cluster is always formed. On the other hand, Zn(II) forms well-defined Zn1 and Zn2 complexes with the DNA-binding domain of GAL4, both of which bind specifically to the UASG DNA sequence. The structural details of the Cd2-, Zn2-, and Zn1GAL4(62*) proteins have been determined by a variety of heteronuclear and 2D NMR techniques. When Cd(II) is exchanged for Zn(II), the cluster appears to expand to accommodate the larger Cd(II) ion as suggested by changes of 2 to 4 Hz in the 3JHN alpha coupling constants for the amino acid residues which form the polypeptide loops enclosing the cluster, residues 10-40. These changes suggest alterations in the backbone phi torsional angles of from 20 degrees to 30 degrees. A metal-ligand structure derived from the 1H-113Cd heteronuclear NMR as well as the polypeptide backbone connectivity around the cluster as determined from short-range 1H-1H NOE's is presented. The metal ions also determine the major folding of GAL4(62*), since the chemical shift dispersion in the entire NH-alpha CH fingerprint region of the 1H-1H COSY spectrum collapses on removal of the metal ion. Two short segments of the GAL4(62*) polypeptide (residues 14-19 and 30-36 in the cluster forms, 12-19 and 30-36 in the Zn1 species) show significant dNN(i,i + 1) NOE's. These short segments of polypeptide chain are the only ones that could be helical in the GAL4(62*).(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1991

Indirect immunofluorescence assay for detection of Helicobacter pylori in human gastric mucosal biopsies.

To determine sensitivity and specificity of immunofluorescence assay (IFA) for detection of Helicobacter pylori, we studied 151 patients. Biopsies of gastric mucosae were obtained for culture, histological testing, and IFA. H. pylori serum antibodies were tested by enzyme-linked immunosorbent assay. IFA was done on Formalin-preserved, paraffin-embedded biopsies by using rabbit anti-H. pylori and goat anti-rabbit gamma globulin-fluorescein isothiocyanate conjugate. The sensitivity and specificity of IFA compared with culture and Warthin-Starry stain were 93 and 95%, respectively. IFA is an accurate method for the diagnosis of H. pylori infection.

Adolescent↗
PubMed1990

In vitro characterization of Salmonella typhi mutant strains for live oral vaccines.

Several Salmonella typhi attenuated mutant strains, suggested as candidates for live oral vaccine, were examined for their characteristics in vitro in comparison with parental strains Ty2 and CDC10-80. Three methods were used: interaction of bacteria with the human monocyte-macrophage U937 cell line evaluated by microscopic examination, bacterial growth in the cell culture medium estimated by absorbance and bacterial resistance to human plasma assessed by the viable count technique. The most informative data were obtained in the test with U937 cells. Ty2 penetrated almost 100% of the cells, multiplied rapidly and caused death of the cells. CDC10-80 infected about 30% of the cells, multiplied slightly and did not kill the cells. The Ty2 mutant galE via EX462 behaved like CDC10-80. Bacteria of the galE Ty21a, Vi + Ty21a, 541 Ty and 543 Ty, found in only 3-4% of the cells, did not multiply within the cells and decreased in number with time. These findings correlate with the reported virulence of these strains for humans. With the second method, the rate of bacterial growth in cell culture medium did not differentiate Ty2, CDC10-80 and EX462. They grew at the same rate and faster than the remaining mutants. The plasma resistance test did not discriminate between EX462 and other mutants. These tests did not reveal any difference between Vi + Ty21a and Vi-Ty21a.

Administration, Oral↗
PubMed1990

Indirect immunoperoxidase and immunofluorescence staining of Bordetella bronchiseptica in formalin-fixed, paraffin-embedded lung tissues of rabbits.

Indirect immunoperoxidase (IP) and immunofluorescence (IF) techniques were developed, and used for the identification of B. bronchiseptica in formalin-fixed, paraffin-embedded lung tissues of 26 rabbits displaying focal chronic interstitial pneumonia, vascular changes, and chronic bronchitis and bronchiolitis. Labelled B. bronchiseptica organisms were observed at the level of the bronchial and bronchiolar mucosa, both in areas affected by chronic bronchitis-bronchiolitis and in zones that were free of lesions. B. bronchiseptica was not observed in areas of focal chronic interstitial pneumonia, nor in vessels exhibiting inflammatory changes. B. bronchiseptica was observed also in a few rabbits that were culturally negative for this agent. The results obtained suggest that B. bronchiseptica could have been related to the lesions of chronic bronchitis and bronchiolitis observed, but not to the changes of focal chronic interstitial pneumonia and vasculitis, as areas affected by these alterations did not exhibit B. bronchiseptica immunoreactivity.

Animals↗
PubMed1990

Expression of chimeric human transferrin genes in transfected human tumor cell lines.

The iron-binding plasma protein transferrin (TF) is essential for supplying iron to cells and the prevention of iron toxicity. Our laboratory has cloned and characterized the human TF gene. Comparison of promoter regions of TF genes from human, chicken, and mouse reveals a strong nucleotide sequence conservation. This study demonstrates that 5' flanking regions of the TF gene are sufficient for directing expression of a heterologous gene in transgenic mice and transfected cells. For cell-specific expression, more than 150 base pairs appear to be required.

Animals↗
PubMed1989

Measurements of lipopolysaccharide (endotoxin) in meningococcal protein and polysaccharide preparations for vaccine usage.

Lipopolysaccharide (LPS, i.e. endotoxin) present in meningococcal outer-membrane protein and polysaccharide preparations made for vaccine use was quantitated by a silver-stain method following SDS-PAGE. The reactivities of LPS in the preparations were also measured by rabbit pyrogenicity and Limulus amoebocyte lysate (LAL) assay. Although rabbit pyrogenicity and LAL assay are more sensitive than the silver stain method, the latter provided an actual amount of LPS present in the protein or in the polysaccharide. For a meningococcal protein preparation, rabbit pyrogenicity showed about one-tenth, and even less by LAL assay, of the actual amount of LPS. This is because protein-bound LPS in meningococcal protein preparations is about 10-fold less active in causing fever in rabbits, and 20- to 40-fold less active in the gelation of LAL than the same amount of a purified free LPS which is generally used as a reference in quantitating LPS in these two assays. As for the small amount of LPS present in a meningococcal polysaccharide preparation, similar LPS content was obtained when measured by the three methods suggesting that the LPS is not bound to the polysaccharide in contrast to that in the proteins mentioned above. The purified meningococcal LPS was pyrogenic in rabbits at 1 ng/kg.

Animals↗
PubMed1987

The propagation of feline panleukopenia virus in micro-carrier cell culture and use of the inactivated virus in the protection of mink against viral enteritis.

Using microcarrier cell culture for the production of virus antigen, a formalin-inactivated feline panleukopenia virus vaccine was evaluated for protection of mink against specific mink enteritis virus infection. The vaccine showed a good immunogenic effect in mink when used either alone or in combination with Clostridium botulinum type C-toxoid and/or Pseudomonas aeruginosa vaccine. A single vaccination induced persistent immune responses for periods of at least 1 year, as evaluated by ELISA and challenge tests. Neither immunological interference between vaccine constituents nor adverse reactions were observed.

Animals↗
PubMed1987

A solid-phase fluorescent immunoassay for detecting canine or mink enteritis parvoviruses in faecal samples.

Mink enteritis virus (MEV) and canine parvovirus (CPV) were detected in faecal samples from experimentally or naturally infected minks and dogs, respectively, using antibody-coated polyacrylamide beads (immunobeads, IB) as the solid phase for immunofluorescence (IF) tests. The specificity and sensitivity of the immunobead assay (IBA) were studied by comparing it with an enzyme-linked immunoassay (ELISA), a haemagglutination (HA) test and an IF test using tissue cultures. The IBA was as sensitive as ELISA, but more sensitive than the HA test and the IF test. Furthermore, the use of IB as the matrix for the immunological reactions allows FITC- or enzyme-conjugated antibodies to be used as indicators of the reactions and a simultaneous investigation of several pathogenic agents.

Animals↗
PubMed1986

A solid phase fluorescent immunoassay for the rapid detection of virus antigen or antibodies in fetuses infected with porcine parvovirus.

A solid phase fluorescent immunoassay using polyacrylamide beads coated with rabbit anti-porcine parvovirus antibodies has been developed and utilized in the diagnosis of porcine parvovirus infection. The antibody-coated beads (immunobeads) were used both to detect virus in mummified fetal tissues and to demonstrate specific antibodies in serum and ovarian follicular fluid. The immunobeads assay (IBA) was as sensitive as ELISA but more sensitive than virus isolation using tissue culture and haemagglutination tests. Both mummified and normal fetuses were obtained after experimental infection of SPF pregnant gilts. Using immunobeads, porcine parvovirus antigen was found in all mummified fetuses, but was found in only 1 out of 17 normal fetuses.

Animals↗
PubMed1986

Porcine parvovirus: propagation in microcarrier cell culture and immunogenic evaluation in pregnant gilts.

Porcine parvovirus was propagated in PK-15 cells cultured in roller bottles or on microcarrier beads. After inactivation, the virus was used as antigen in the preparation of vaccines. The immunogenic potency and safety of the vaccines were evaluated in specific pathogen free pregnant gilts and guinea pigs. Experimental challenge tests determined the efficacy of the vaccine in preventing porcine parvovirus transplacental infection. Neither viral antigens nor specific antibodies were detected in fetuses from vaccinated gilts. In contrast, fetal death and, or, mummification occurred when unvaccinated gilts were infected. Both virus and, or, antibodies were also detected in fetuses from these unvaccinated gilts. Serum conversion after vaccination was assayed by microserum neutralisation using guinea pig erythrocytes as cell indicators and by haemagglutination inhibition tests. Viral antigens in fetal tissues were detected using ELISA, the immunobeads technique, the haemagglutination test and by virus isolation.

Animals↗