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Biomedical subjects

J Romero

Publications and source records attributed to J Romero.

At least 163 records · Page 9Linked to original sources
PubMed1994

Late complications after total hip replacement in renal allograft recipients.

Seventy nine hips in 53 recipients of renal allografts were treated by cemented total hip replacement for avascular necrosis of the femoral head between 1972 and 1992. Eight hips in 6 patients required revision for aseptic loosening after a mean of 11.2 years. Three replacements in 3 patients became infected with salmonella enteritidis after a mean of 6.2 years. One was revised, one had a disarticulation of the hip, and the third was treated with long term antibiotics. Survivorship analysis for total hip replacement and the renal allografts showed a hip reoperation rate of 9.9% at 10 years and 54.6% at 15 years with mortality rates of 32.2% and 42.2% respectively. Thus patients surviving 15 years are at a higher risk of failure of the prostheses than of dying.

Adult↗
PubMed1994

Fractures of the dorsolumbar spine with neurological lesions. A comparison of different treatments.

Seventy-nine fractures of the dorsolumbar junction with neurological lesions have been studied retrospectively at an average follow up of 29 months. Sixteen patients were treated conservatively and 63 were operated on using the techniques of laminectomy. Harrington rods, supplemented Harrington fixation and the Malaga transpedicular fixator. Both the angle of kyphosis and the percentage of vertebral wedging were comparatively lower when the Malaga fixator was used. Pain and the angle of kyphosis were related statistically, the Cobb angle being greater for those with pain. Surgical treatment allowed patients to sit up earlier, and those with a Malaga fixator spent a shorter time in hospital. No differences were found in neurological improvement.

Adolescent↗
PubMed1994

Serotype-specific detection of bean common mosaic potyvirus in bean leaf and seed tissue by enzymatic amplification.

An assay involving reverse transcription and polymerase chain reaction (PCR) is described for specific detection of serotypes A and B BCMV isolates in bean leaf and seed tissues. Three oligonucleotide primers designed according to the sequence data available allow, in appropriate combination, serotype-specific detection of BCMV. The sensitivity of the method was sufficient to detect BCMV in as little as 100 fg and 50 pg of infected leaf and seed tissues, respectively.

Base Sequence↗
PubMed1994

Evolutionary relationships among bean common mosaic virus strains and closely related potyviruses.

Bean common mosaic virus (BCMV) consists of a large number of strains with complex and controversial relationships among them and with other potyviruses that infect legumes. In order to elucidate the BCMV taxonomic pattern and its evolutionary implications, a phylogenetic analysis has been carried out. The analysis of the coat protein gene and 3' non-coding region (NCR) sequences recently obtained by us and other currently available potyviral sequences confirms the clustering of viruses comprised in BCMV strains with other closely related potyviruses and reveals the great informative content of 3' NCR, suggesting a more relevant role for this region in phylogenetic analysis.

Amino Acid Sequence↗
PubMed1994

Infectious transcripts from PCR-amplified broad bean mottle bromovirus cDNA clones and variable nature of leader regions in RNA 3 segment.

The genome of broad bean mottle bromovirus (BBMV) contains three positive-sense ssRNA segments, each capped with m7GpppA. Full-length transcribable cDNA clones for four strains of BBMV were constructed by employing reverse transcriptase-PCR (RT-PCR) and a high fidelity Vent DNA polymerase. The transcribed BBMV RNAs contained a 5' non-viral G residue and, although delayed, produced symptoms similar to those observed in plants infected with authentic virion RNAs. The transcripts replicated inefficiently in protoplasts. In contrast, transcript-derived progeny BBMV RNAs had the repaired termini, were as infectious as the authentic BBMV RNAs and replicated to high levels in protoplasts. In vitro translation of synthetic RNAs confirmed the previously proposed gene expression strategy for BBMV. Sequencing of virion RNAs from the Bawden strain revealed two forms of BBMV RNA3 components, the longer form containing 21 5' extra nucleotides derived by the duplication of two short 5' leader regions. The relative concentration of the two RNA 3 forms was found to be host-dependent, with the longer form prevailing in broad bean and Nictiana clevelandii infections and the shorter form in bean infections.

Base Sequence↗
PubMed1994

Possible involvement of the lysine epsilon-aminotransferase gene (lat) in the expression of the genes encoding ACV synthetase (pcbAB) and isopenicillin N synthase (pcbC) in Streptomyces clavuligerus.

Streptomyces clavuligerus produces the beta-lactam antibiotics penicillin N, O-carbamoyldeacetylcephalosporin C and cephamycin C. We characterized a wild-type DNA region which restores antibiotic formation to a mutant strain named NP1, previously shown to exhibit depressed activities for two early enzymes of cephalosporin synthesis, delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine synthetase (ACVS) and isopenicillin N synthase (IPNS). L-Lysine epsilon-aminotransferase (LAT) assays and alpha-AAA feeding experiments suggested that strain NP1 is a lat mutant. NP1 recovered LAT, ACVS and IPNS activities when transformed with the cloned region. DNA sequencing showed that this region encodes the entire LAT gene (lat), required for the conversion of L-lysine to the beta-lactam precursor L-alpha-aminoadipic acid (alpha-AAA), as well as the upstream half of the ACVS gene (pcbAB). The activities of ACVS and IPNS appear to depend upon LAT expression. Gene fusions constructed to investigate promoter activities in the cloned region support a model of interdependence in the expression of the genes for LAT, ACVS and IPNS (pcbC).

Amino Acid Sequence↗
PubMed1994

Variations in corneal sensitivity with hydrogel contact lenses.

Changes in corneal sensitivity were studied in two groups of healthy subjects who wore hydrogel contact lenses: 44 persons whose lenses contained 38% water, and 23 who wore lenses of 55% water content. Corneal sensitivity decreased in both groups during the first 8 h following insertion; the decrease was more marked in the group who wore 38% water lenses. Changes in corneal tactile sensitivity were greater in women than in men, and determinations in different corneal zones showed that the central zone was less affected in sensitivity than any of the peripheral zones. After lenses were removed, tactile sensitivity showed full recovery within 4 h.

Adolescent↗
PubMed1994

Antibiotic resistance and penicillin tolerance in clinical isolates of group B streptococci.

The aim of this study was to determine the susceptibility patterns of 100 group B streptococcal strains isolated in our hospital and to ascertain tolerance to penicillin by determining quantitative killing curves. We found two strains with intermediate susceptibility to penicillin and eight strains to ampicillin. Seventeen isolates were tolerant to penicillin, with bacterial counts decreasing 2 to 3 log during the first 8 h but still above 10(2) CFU/ml after 24 h. The kinetic study shows that penicillin tolerance is not rare among group B streptococci isolated in our hospital.

Ampicillin Resistance↗
PubMed1993

Characterization of defective interfering RNA components that increase symptom severity of broad bean mottle virus infections.

Several strains of the broad bean mottle virus (BBMV), an icosahedral tripartite plant RNA virus, which show distinct reactions on certain plant hosts have been described (K. M. Makkouk et al., Neth. J. Plant Pathol. 94, 195-212, 1988). Here we report defective interfering (DI) RNAs encapsidated in two BBMV strains from Morocco and Tunisia. While not effective in some plants, these DI RNAs exacerbated the severity of symptoms in others. The most dramatic, lethal effect of DI RNAs has been found on pea (Pisum sativum, cv. Rondo) seedlings. Sequence analysis has revealed that the DI RNAs were derived by single in-frame central deletions of 448 to 537 nt in the corresponding genomic RNA2 components. A comparison of the intensities of full-length RNA2 bands from DI molecule-containing and DI molecule-deficient virion RNA preparations revealed that the DI RNAs decreased the level of RNA2 components in total RNA preparations. The differences between corresponding virion RNAs were much smaller. This suggests an interference with RNA replication. In vitro assays and an analysis of the polyribosomal RNA fractions confirmed the translational activity of DI RNAs. This paper reports the first description of natural DI RNAs in tripartite isometric plant RNA viruses.

Base Sequence↗
PubMed1993

Chordoma: results of radiation therapy in eighteen patients.

Between 1975 and 1990, eighteen patients with a histologically proven diagnosis of chordoma were treated at our institution. All patients initially underwent a surgical procedure and were referred for irradiation due to residual disease or postsurgical relapse. The mean dose administered was 50.1 Gy (range, 29.9-64.8 Gy). Eight patients were treated according to a hyperfractionated schedule. The overall actuarial 5-year survival and 5-year progression-free survival were 38% and 17%, respectively. The progression-free interval was longer for patients receiving doses greater than 48 Gy when compared with doses below 40 Gy (actuarial 5-year progression-free survival of 31 +/- 35% vs. 0%, respectively; p = 0.04). We conclude that in the treatment of chordoma, the administration of high radiation doses may increase the disease-free interval. The objective response and dose-response relationships were analyzed in twelve patients for whom sequential CT scans were available.

Adult↗
PubMed1993

[Comparative in vitro activity of new oral macrolides against Streptococcus pyogenes strains].

Some recently introduced macrolides have several clinical advantages over erythromycin. Azithrommcin, a prototype of these new macrolides could be a good alternative for the treatment of streptococcal pharyngitis, even over penicillin, whose failure rate can be as high as 30%. The aim of this study was to evaluate the in vitro susceptibility of 120 strains of S pyogenes isolated between 1990 and 1992 (40 per year), from diverse infections (specially tonsillitis). We determined Minimal Inhibitory Concentrations (MIC) of azithromycin, clarithromycin, roxithromycin, erythromycin and penicillin using the agar dilution method and the Minimal Bactericidal Concentration (MBC) by tube dilution for azythromycin and erythromycin. The MIC 90 for the new macrolides ranged from 0.03 to 0.12 microgram/ml, and was 0.03 microgram/ml for erythromycin and penicillin (not different). All strains were susceptible to all antibiotics and the date of isolation did not influence susceptibility. The MBC for azithromycin was 0.12 microgram/ml (identical to its MIC), which demonstrates the bactericidal effect of this antibiotic. It is concluded that this in vitro data supports the potential role of these new macrolides in the treatment of streptococcal infections.

Anti-Bacterial Agents↗
PubMed1993

[Comparative study of pneumococcal bacteremia in patients with and without HIV infection].

A retrospective study of bacteriemias due to S. pneumoniae in adults is performed, from all the cases observed in our hospital during the 1989-1990 period. We compare the clinical characteristics of the disease depending if the affected patients were infected or not by the human immunodeficiency virus (HIV). In the considered period bacteriemia due to S. pneumoniae has been diagnosed in 12 patients with HIV infection and 29 without it. Ten of the twelve patients with HIV infection (83.3%) were in Stage IV (CDC) of the disease, staying the rest in a less developed phase of the disease. Age was significantly higher in non-HIV patients (p < 0.001) and a high percentage of patients in this group (75%) showed some disease considered as predisposing to bacteriemia due to S. pneumoniae. When a respiratory foci was present, VIH positive individuals showed more frequently bilateral radiologic infiltrates and less frequently pleural effusion. Leucocyte count when diagnosis was done were significantly higher in non-HIV group. Sensibility of isolated S. pneumoniae was similar in the two groups, being the immediate mortality related with bacteriemia due to S. pneumoniae higher in the non-HIV group. In our center 29.3% of bacteriemias due to S. pneumoniae are diagnosed in patients with HIV infection. This disease in itself could constitute an added risk factor in the development of bacteriemia due to S. pneumoniae.

Adult↗