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R Peralta

Publications and source records attributed to R Peralta.

8 recordsLinked to original sources
PubMed2001

[Pilot study with the monoclonal antibody IOR-C5 as a potential agent of radioimmunoscintigraphy in colorectal cancer].

UNLABELLED: IOR C-5 is a G1 immunoglobulin type intact murine monoclonal antibody (MAb) that was developed in the Center of Molecular Immunology in Havana City, Cuba. In immunohistochemical studies, this demonstrated a significant affinity for the epithelial tissues so that it was used in a pilot clinical study to perform a radioimmunoscintigraphy of the colorectal primary tumors and their locoregional recurrences. It was labeled with 99mTc using the Schwarz method, with a > 95% performance. Planar images of the chest, abdomen and pelvis were performed at 10 minutes, 4-6 hours and 18-24 hours post-injection in the anterior and posterior projections and the SPECT was performed 4-6 hours and 18-24 hours post-injection of 1.85 GBq 99mTC. This study has aimed to verify in vivo the capacity of ior-C5 MAb to accumulate in the malignant colorectal lesions. ior-C5 accumulated in 5 out of the 7 patients who were studied and who were suffering from colorectal cancer or in whom there was suspicion of recurrence. There was a negative case of primary tumors, which was an adenocarcinoma in situ in a tubular-papillary adenoma. The second case with a negative radioimmunoscintigraphy was a true negative case. CONCLUSIONS: It can be concluded that even though the number of patients is quite low, ior-C5 fulfilled the expectations of recognizing the epitope expressed in colorectal tumors in an in vivo human environment.

Adenocarcinoma↗
PubMed2001

Description of staphylococcus serine protease (ssp) operon in Staphylococcus aureus and nonpolar inactivation of sspA-encoded serine protease.

Signature tagged mutagenesis has recently revealed that the Ssp serine protease (V8 protease) contributes to in vivo growth and survival of Staphylococcus aureus in different infection models, and our previous work indicated that Ssp could play a role in controlling microbial adhesion. In this study, we describe an operon structure within the ssp locus of S. aureus RN6390. The ssp gene encoding V8 protease is designated as sspA, and is followed by sspB, which encodes a 40.6-kDa cysteine protease, and sspC, which encodes a 12.9-kDa protein of unknown function. S. aureus SP6391 is an isogenic derivative of RN6390, in which specific loss of SspA function was achieved through a nonpolar allelic replacement mutation. In addition to losing SspA, the culture supernatant of SP6391 showed a loss of 22- to 23-kDa proteins and the appearance of a 40-kDa protein corresponding to SspB. Although the 40-kDa SspB protein could degrade denatured collagen, our data establish that this is a precursor form which is normally processed by SspA to form a mature cysteine protease. Culture supernatant of SP6391 also showed a new 42-kDa glucosaminidase and enhanced glucosaminidase activity in the 29 to 32 kDa range. Although nonpolar inactivation of sspA exerted a pleiotropic effect, S. aureus SP6391 exhibited enhanced virulence in a tissue abscess infection model relative to RN6390. Therefore, we conclude that SspA is required for maturation of SspB and plays a role in controlling autolytic activity but does not by itself exert a significant contribution to the development of tissue abscess infections.

Adhesins, Bacterial↗
PubMed2000

Airway trauma.

Traumatic airway injuries fortunately are rare. While sometimes injuries are obvious and initial management straightforward, frequently the diagnosis is difficult. Prompt diagnosis of airway injuries requires a high index of clinical suspicion, complemented by judicious use of endoscopy and radiological imaging. Initial management can be complicated by associated head, neck, and thoracic injuries. Importantly, a patient's airway can be lost because of injudicious use of sedation or failure to be properly cautious during attempts at airway management and endotracheal intubation. Mortality rates and the incidence of late complications remain high and have been related to delays in diagnosis and definitive treatment.

Airway Obstruction↗
PubMed2000

Synthetic peptide immunogens elicit polyclonal and monoclonal antibodies specific for linear epitopes in the D motifs of Staphylococcus aureus fibronectin-binding protein, which are composed of amino acids that are essential for fibronectin binding.

A fibronectin (Fn)-binding adhesin of Staphylococcus aureus contains three tandem 37- or 38-amino-acid motifs (D1, D2, and D3), which function to bind Fn. Plasma from patients with S. aureus infections contain antibodies that preferentially recognize ligand induced binding sites in the D motifs and do not inhibit Fn binding (F. Casolini, L. Visai, D. Joh, P. G. Conaldi, A. Toniolo, M. Höök, and P. Speziale, Infect. Immun. 66:5433-5442, 1998). To eliminate the influence of Fn binding on antibody development, we used synthetic peptide immunogens D1(21-34) and D3(20-33), which each contain a conserved pattern of amino acids that is essential for Fn binding but which cannot bind Fn without N- or C-terminal extensions. The D3(20-33) immunogen promoted the production of polyclonal antibodies that were 10-fold more effective as inhibitors of Fn-binding to the D3 motif than antibodies obtained by immunizing with an extended peptide D3(16-36), which exhibits functional Fn binding. The D3(20-33) immunogen also facilitated the production of a monoclonal antibody, 9C3, which was highly specific for the epitope SVDFEED, and abolished Fn binding by the D3 motif. When mixed with polyclonal anti-D1(21-34) immunoglobulin G, 70% inhibition of Fn binding to the three tandem D motifs was achieved compared to no more than 30% inhibition with either antibody preparation alone. Therefore, by immunizing with short synthetic peptides that are unable to bind Fn, we have effectively stimulated the production of antibodies specific for epitopes comprised of amino acids that are essential for Fn binding. Although these epitopes occur within a conserved pattern of amino acids that is required for Fn binding, the antibodies recognized specific linear epitope sequences and not a conserved structure common to all repeated motifs.

Adhesins, Bacterial↗
PubMed1999

[Radioimmunoscintigraphy of colorectal cancer using the anti-CEA monoclonal antibody BW 431/26. Final results].

The anti-carcinoembryonic antigen (CEA) antibody, BW 431/26 (Scintimun CEA, Behringwerke, Marburg, Germany ) labeled with technetium pertechnectate (99mTc), is an intact immunoglobulin G1, monoclonal antibody that has been used to image colorectal cancer. Planar and SPECT images of chest, abdomen and pelvis were performed at 10 minutes, 4-6 and 18-24 hours after the intravenous antibody injection. 44 patients were studied and the pathological antibody concentration localization by radioimmunoimaging (RI) were correlated with surgical, clinical and other imaging modality findings to validate the RI. The RI was positive in 29 patients and negative in the other 15 patients. The CEA and CA 19.9 were elevated in the serum of some patients with primary tumors or recurrence. The HAMA were determined in all the patients before and after the RI.

Adult↗
PubMedDate not supplied

Tandem subdiaphragmatic and pleural sequelae due to lost gallstones following cholecystectomy.

We report two similar thoracoabdominal complications we encountered due to retained gallstones after cholecystectomy. These patients had had an open cholecystectomy after a failed laparoscopic attempt, with spillage of gallbladder debris intraoperatively. They were admitted more than 12 months later with subdiaphragmatic abscesses. Attempted computerized axial tomography (CT) guided drainage of these abscesses resulted in these patients developing pleural fluid collections, which required surgical drainage. The patients underwent exploratory laparotomies, and drainage of the subdiaphragmatic abscesses had revealed gallstones within the abscess cavity. A detailed presentation of these cases, with review of current literature and clinicopathologic issues for discussion are described.

Aged↗