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Biomedical subjects

F Rodriguez

Publications and source records attributed to F Rodriguez.

At least 55 records · Page 3Linked to original sources
PubMed1996

Radiofrequency as a lesioning model in experimental spinal cord injury.

Many models have been developed to study spinal cord injury (SCI), such as cryogenic lesioning, hot water injury, scalpel lesioning, compressive trauma using clips, electromechanical devices, extradural cuffs, and weight-drop techniques. In this study, the radiofrequency (RF) lesion was used for inducing an experimental SCI in cats. The neuropathology was correlated with the MRI. In this model, 4 cats were injured at the thoracic spinal cord (T11-T12) with a lesion of 65 degrees C for 1 min using a micromanipulated penetrating RF electrode. The MRI of the lesions after 2, 3, 5, and 6 weeks post-injury as well as the correlative histological changes were obtained. The RF-induced lesion was discrete with little spreading across the spinal cord. There was a good correlation between the histopathology findings and the MRI. We conclude that experimental RF lesioning of the spinal cord can produce a consistent lesion with predictable histopathological changes in experimental animals. A 65 degree C injury for 1 min induced a clinical picture of an incomplete SCI. The RF lesioning should be considered as a new model to study SCI, particularly those with a penetrating component.

Animals↗
PubMed1996

Collagen dysplasia in a litter of Garafiano shepherd dogs.

A connective tissue disease resembling the human Ehlers-Danlos syndrome is reported in three Garafiano shepherd dogs from the same litter. The clinical signs included skin hyperextensibility and fragility, joint laxity, and ocular lesions. Microscopical studies showed abnormalities in the packing of collagen in fibrils and fibres in the skin. Systemic connective tissue defects were demonstrated in one necropsied puppy.

Animals↗
PubMed1996

An immunohistochemical method of detecting Mycoplasma species antigens by use of monoclonal antibodies on paraffin sections of pneumonic bovine and caprine lungs.

Lung samples from pneumonic lesions in cattle and goats, naturally or experimentally infected with strains of the Mycoplasma mycoides cluster, were fixed in formalin and embedded in paraffin. An immunohistochemical technique using monoclonal or polyclonal antibodies was performed on tissue sections in order to detect Mycoplasma antigens. Four monoclonal antibodies (MAbs), one (2A3) raised against M. mycoides ssp. mycoides small colony (SC) and large colony (LC), two (1D3 and 5E5) against M. mycoides ssp. capri, and one (5A10) against M. bovis, were used. A range of polyclonal antibodies, raised to the individual subspecies of the M. mycoides cluster, and one to Pasteurella haemolytica, was also used. The MAb 2A3 showed positive immunostaining in lung sections from cattle and goats naturally and experimentally infected with M. mycoides ssp. mycoides SC and LC, but not with pneumonic lesions of cattle and goats due to other members of the M. mycoides cluster, M. bovis or Pasteurella spp. The MAb 1D3 showed immunostaining in lung sections from goats naturally and experimentally infected with M. mycoides ssp. capri, but again not with pneumonic lesions caused by other members of the M. mycoides cluster, M. bovis or Pasteurella spp. The MAb 5E5 immunoreacted in sections from pneumonic lesions from all animals infected with one of the three M. mycoides cluster subspecies used in the study, but not with M. bovis or Pasteurella infected tissue. Immunoreaction was mainly found in the cell debris around necrotic areas, as well as in macrophages, neutrophils and epithelial cells. The localization of antigens of the M. mycoides cluster using polyclonal antisera followed basically the same pattern as that obtained with the monoclonals. However, a wide cross reactivity was found between different antisera and relatively high background immunostaining was also seen, especially in necrotic areas. The results suggest that immunohistochemical methods using monoclonal antibodies are useful tools for the diagnosis and study of the pathogenesis of pneumonia caused by the Mycoplasmas of the M. mycoides cluster.

Animals↗
PubMed1996

Nephroprotective effect of cilastatin in allogeneic bone marrow transplantation. Results from a retrospective analysis.

Cilastatin, an inhibitor of the tubular brush border enzyme dehydropeptidase-I, is added in a fixed combination to imipenem. Cilastatin has been demonstrated in different animal models and in one clinical trial, to reduce the nephrotoxicity associated with cyclosporin A. To evaluate a possible nephroprotective effect of cilastatin following allogeneic BMT we conducted a retrospective analysis of 104 patients transplanted in our BMT Unit from January 1991 to January 1995. Imipenem/cilastatin (I/C) was used in a non-randomized manner in 64 patients during this period. Acute renal failure (ARF) was diagnosed in 32 patients (30%). ARF was not associated with gender, sepsis, conditioning regimen, underlying disease, bilirubin, or age. VOD occurred in 12/32 (37.5%) of patients with ARF whereas it occurred in only 7/72 (9.7%) of patients without ARF (P < 0.0007). ARF was not correlated with use of aminoglycosides, vancomycin, ciprofloxacine, ceftazidime or amphotericin-B. However, 13 patients of 64 exposed to I/C (20.3%) developed ARF vs 19 of 40 patients (47.5%) who were not exposed to I/C (P < 0.003; OR 0.28). Stratified analysis and multiple logistic regression confirmed the I/C nephroprotective action. The mean cyclosporin A levels in the I/C group were significantly decreased (208.6 +/- 64.9) vs the non-I/C group (265 +/- 118). We conclude that these results suggest I/C may counteract acute cyclosporin A nephrotoxicity following BMT and further prospective clinical trials are needed to confirm if routine administration of cilastatine confers benefit in the BMT setting.

Acute Kidney Injury↗
PubMed1995

Highly specific confirmatory western blot test for African swine fever virus antibody detection using the recombinant virus protein p54.

A Western blot technique using a recombinant protein has been developed to confirm positive results obtained in African swine fever (ASF)-specific antibody detection by ELISA. The new confirmatory Western blot is based on the use of protein p54, one of the most antigenic ASF virus structural proteins, expressed in Escherichia coli fused to the N-terminus of MS2 polymerase. The recombinant Western blot assay was highly specific and equally sensitive for ASF virus-infected pigs detection as the conventional Western blot, which uses virus-induced proteins ranging in molecular weight between 23 and 35 kDa. The novel Western blot assay provides a simpler interpretation of the test, eliminates the possibility of false-positive reactions produced by cellular compounds that contaminate the antigen employed in the conventional technique, and avoids the use of live virus in antigen production.

African Swine Fever↗
PubMed1995

Undetectable expression of genomic progesterone receptor in human spermatozoa.

The expression of genomic progesterone receptor in human ejaculated spermatozoa was investigated. Spermatozoa from 10 fertile donors who exhibited normal semen parameters were analysed. Indirect immunofluorescence and an enzyme immunoassay using monoclonal antibodies against genomic progesterone receptor were used. Different types of spermatozoa were studied: fresh, post-swim-up (migrated), capacitated and post-artificial induction of the acrosome reaction by calcium ionophore A23187. Progestin receptor-rich T47D human breast cancer cells were used as a positive control, and progestin receptor-poor MDA-MB-231 human breast carcinoma cells were used as a negative control. Genomic progesterone receptor was not detected in fresh, migrated, capacitated and post-acrosome reaction induction human spermatozoa and MDA-MB-231 cells by either indirect immunofluorescence or enzyme immunoassay. However, in T47D cells a mean concentration of 1043.2 +/- 125.2 fmol genomic progesterone receptor/mg protein was observed by enzyme immunoassay, and indirect immunofluorescence results were positive using both flow cytometry and fluorescence microscopy. These findings suggest that the effect of progesterone on human spermatozoa is not mediated by genomic progesterone receptor.

Antibodies, Monoclonal↗
PubMed1995

An operon encoding a novel ABC-type transport system in Bacillus subtilis.

Downstream from the surfactin synthetase operon in Bacillus subtilis a new operon-type structure has been localized which, on the basis of sequence determination, potentially encodes an ABC-type transport system. The 268 amino acid protein, the product of orf1, represents the solute-binding component of the system whereas the orf2 product, a 234 amino acid protein, is the transmembrane component. Finally orf3 potentially encodes a typical 241 amino acid ATP-binding protein involved in energy supply. Comparison of the three proteins with the subunits of other ABC-type systems suggests that this new system is involved in amino acid transport.

ATP-Binding Cassette Transporters↗
PubMed1995

Determination of hepatitis delta virus RNA by polymerase chain reaction in acute and chronic delta infection.

The objective of this study was to evaluate the usefulness of hepatitis delta virus (HDV) RNA detection by polymerase chain reaction (PCR) in acute and chronic D hepatitis and to correlate with HDV-RNA detection by dot blot and hepatic delta antigen. Serum samples from 33 patients with acute hepatitis B surface antigen (HBsAg)-positive hepatitis (15 with hepatitis B and D coinfection, 8 with HDV superinfection, and 10 with acute hepatitis B), 85 patients with chronic HBsAg-positive hepatitis (73 with chronic D hepatitis and 12 with chronic B hepatitis), and consecutive serum samples from nine patients with chronic D hepatitis treated with interferon alfa-2b were studied. HDV-RNA was detected by PCR in 93% of the patients with hepatitis B and D coinfection, in 100% of the patients with hepatitis D superinfection, and in 1 of the 10 patients with acute hepatitis B who subsequently seroconverted to total antibody to hepatitis delta antigen (HDAg), whereas HDV-RNA was found by dot blot technique in 60% of the hepatitis B and D coinfection cases, in 62.5% of the patients with hepatitis D superinfection, and in none of the acute hepatitis B cases. In chronic D hepatitis, HDV-RNA tested positive by PCR assay in 97% of patients with intrahepatic HDAg, in one patient with undetectable hepatic HDAg, and in none of the patients with chronic hepatitis B. In the treated patients, HDV-RNA was observed to become negative by PCR only in the three patients who had a persistent response to interferon.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1994

Characterization of the surfactin synthetase multi-enzyme complex.

Three subunits (srfAORF1, srfAORF2 and srfAORF3) of the Bacillus subtilis surfactin synthetase multi-enzyme complex have been identified by SDS-PAGE and Western blot analyses. In accordance with the sequence analysis of the surfactin (srfA) operon, the protein subunits have a molecular mass of 402,000 Da, 401,000 Da and 144,000 Da, respectively. Confirmation of the identity of the proteins was obtained by analysing the total protein content of a number of mutant strains which harbour deletions or insertions either in the srfA promoter or in different positions within the srfA operon. The three subunits were partially purified by means of a series of chromatographic steps including ion-exchange chromatography, hydrophobic chromatography and gel filtration chromatography. The partially purified proteins were used in activity assays to establish their amino-acid recognition specificity. In agreement with previously published results, this analysis showed that srfAORF1 recognizes glutamic acid and Leu, srfAORF2 recognizes Val, aspartic acid and Leu and srfAORF3 recognizes Leu. In addition, the subunits can activate and bind other amino acids, although with lower specificity. In particular, srfAORF1 binds Val, Ile and aspartic acid, srfAORF2 glutamic acid and Ile and srfAORF3 Ile and Val. Competition experiments as well as sequence comparison strongly suggest that the Leu binding sites of the three subunits can accept, beside Leu, Ile and Val. The kinetic parameters of srfAORF3 for Leu, Ile and Val have been determined.

Amino Acid Sequence↗
PubMed1994

Bilateral effect of unilateral vasectomy on testicular testosterone biosynthesis.

Twelve immature male dogs underwent a left vasectomy (group A). An additional five underwent a sham operation (group B). Sixteen weeks after the surgery, the bilateral mean values for caudal epididymal sperm content, the percentage of motile spermatozoa, intratesticular testosterone concentration, and testicular secretion of androgen-binding protein (in vitro) were significantly lower in group A. The mean peripheral serum testosterone responses 3 hours after human chorionic gonadotropin stimulation (3,000 IU) were significantly lower in group A than in group B (6.3 ng/mL v 9.5 ng/mL). These findings indicate a bilateral deficiency in both Leydig and Sertoli cell secretory function in unilaterally vasectomized dogs, resulting in impaired bilateral spermatogenesis and sperm maturation. The authors suggest that unilateral injuries of the vas deferens during hernia operations in children may result in bilateral testicular dysfunction.

Androgen-Binding Protein↗
PubMed1994

Reduction in food and water intake induced by microinjection of interleukin-1 beta in the ventromedial hypothalamus of the rat.

Interleukin-1 (IL-1) is a cytokine which is released during immune activation and mediates some of the host's responses to infection and inflammation. Increasing evidence suggests that it also has a role as an intrinsic neuromodulator in the central nervous system. We report here that microinjections of 5 and 30 ng (286 fmol and 1.71 pmol) of recombinant human IL-1 beta in the ventromedial nucleus of the hypothalamus (VMH) of adult male rats time- and dose-dependently induce anorexia and weight loss in two experimental paradigms: rats allowed free-access to food and water and food-restricted rats trained to press a lever for food on a fixed ratio 10 schedule. IL-1 beta (5 ng) diminished food and water consumption by 45 and 30%, respectively, and decreased body weight for at least 24 h postinjection in rats fed ad lib. These effects were more severe and lasted at least 48 h after infusion of the larger dose of 30 ng. The IL-1 beta-induced anorexia and weight loss were neither as large nor as long-lasting in food-restricted rats. Operant responding for food was decreased 2-4 h postinfusion of 5 ng IL-1 beta and 2-8 h after 30 ng IL-1 beta, but in both cases returned to baseline within 24 h. Body weight was decreased compared to saline injections from 4 to 24 h postinfusion. Nevertheless, when allowed to eat ad lib for the 24 h immediately following the behavioral testing, body weight returned to control (5 ng) or near control levels (30 ng).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗