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Biomedical subjects

L Caro

Publications and source records attributed to L Caro.

At least 19 recordsLinked to original sources
PubMed2004

[Evaluation of a pharmaceutical care program to improve adherence to antiretroviral therapy].

OBJECTIVE: To establish the impact of a pharmaceutical care program on the improvement of adherence to antiretroviral therapy, and on patient immunologic and virologic outcome. MATERIALS AND METHODS: A multicenter, observational, prospective study in a HIV-infected patient cohort under treatment with antiretrovirals selected by random sampling in 19 Spanish hospitals. The study lasted 12 months, in which the program was applied through a baseline preprocedural visit and 4 quarterly visits. Adherence estimation was based on pill counting. An adherence > or = 90, or > or = 95% was considered adequate (in two time points). RESULTS: 541 patients were included, most of them were males (68.8%) between 20 and 78 years of age. Major risk groups included injecting drug users (43.4%) and heterosexuals (29.4%). Sixty percent had already received treatment for more than 3 years. Mean baseline viral load and CD4 count values were 32,866 copies/ml and 485 cells/mm3, respectively. Throughout the study a slight increase in the percentage of adherent patients was seen; however, statistical significance was not reached (64.3 and 79.2% of patients showed an adherence > 95 and > 90%, respectively, during the fourth quarter, versus 59.8 and 75.5% at baseline). A statistically significant decrease in viral load and increase in CD4 cells was seen following program application. The percentage of patients with a viral load < 200 copies/ml was 72.2, 76.7, and 75.0% at the 2nd, 3rd, and 4th quarters, respectively, versus 64.2% at baseline. CD4 cell counts increased by 50 cells/mm3 on average from the start to the end of follow-up. CONCLUSIONS: Patients included in the program had a good immunologic and virologic outcome, and a trend towards an increased percentage of patients with good adherence was also seen. These results confirm the need to implement follow-up programs for patients receiving antiretrovirals in order to ensure maximum therapeutic benefits.

Adult↗
PubMed1999

Characterization in vitro and in vivo of a new HU family protein from Streptococcus thermophilus ST11.

Streptococcus thermophilus is a thermophilic gram-positive bacterium belonging to the lactic acid group. We report the isolation and characterization of a new 9.6-kDa DNA-binding protein, HSth, belonging to the HU family of nucleoid-associated proteins. The hsth gene was isolated in a 2.5-kb genomic region, upstream of a gene with strong homology to Lactococcus lactis pyrD. It is transcribed from a single E. coli sigma(70)-like promoter. Based on its high level of sequence similarity to B. subtilis and E. coli HU, HSth appears to be an HU homologue. The HSth protein shows biochemical and functional properties typical of HU proteins from gram-positive bacteria, being heat-stable, acid-soluble, and homodimeric. When expressed in HU-deficient E. coli cells, HSth supported the growth of bacteriophage Mu as efficiently as E. coli HU homo- and heterodimeric proteins. It did not, however, display any IHF-specific functions. Finally, we show that HSth binds to linear DNA with no apparent specificity, forming protein-DNA complexes similar but not identical to those observed with E. coli HU proteins.

Amino Acid Sequence↗
PubMed1998

Transpyloric enteral feeding in critically ill children.

BACKGROUND: Nutrition is important in childhood because the child has a lower energy reserve than the adult and a higher demand for calories because of ongoing growth. In this study, the utility of transpyloric enteral feeding (TEF) in critically ill children was evaluated. METHODS: A prospective, descriptive study was made in a pediatric intensive care unit of a tertiary pediatric center of 41 critically ill children, 30 after surgical procedures and 11 with nonsurgical illness, aged 8 days to 12 years, who received transpyloric enteral feeding with 8- or 10-Fr weighted feeding tubes. Analysis was made of tolerance and complications (vomiting, abdominal distension, excessive gastric residual, diarrhea, and pulmonary aspiration) of TEF. RESULTS: The mean duration of TEF was 19.5 +/- 26.8 days (range, 1-120 days). The administration of sedative agents or inotropic drugs did not alter toleration of TEF. Eight of 12 patients treated with continuous infusion of vecuronium tolerated TEF without complications. Eleven gastrointestinal complications occurred in 10 patients, abdominal distension and excessive gastric residual in 7 (17%), and diarrhea in 4 (9.7%). In 7 patients gastrointestinal complications improved, with decreasing use or transitory interruption of TEF, but in 4 patients (9.7%), TEF had to be withdrawn. Gastrointestinal complications were more frequent in postsurgical than in nonsurgical patients (p < 0.001). No patients suffered from pulmonary aspiration, and the incidence of pulmonary infection and hepatic dysfunction diminished during TEF. CONCLUSIONS: Transpyloric enteral feeding is a good method of nutritional support in critically ill children and can be used in patients treated with neuromuscular blocking agents. The frequency and severity of complications and the risks of pulmonary infection and hepatic dysfunction related to TEF are low.

Child↗
PubMed1998

[Endoscopic ultrasonography in the diagnosis of submucosal tumors of the upper digestive tract].

Endoscopic Ultrasonography (EUS) was performed in 520 patients. In 78 subjects, it was indicated because of endoscopic suspicion of submucosal tumors (SMT), later confirmed in 67 patients. Thirty seven patients were symptomatic; in 22 patients the finding was incidental and in 7 the indication was unknown. According to the ecogenic pattern of the lesions found and the layer of the tumor origin the following were diagnosed: 14 leiomyomas, 1 lipoma, 3 granular cell tumors and 2 without precise diagnosis in the esophagus. Thirty leiomyomas, 6 leiomyosarcomas, 4 lipomas, 4 ectopic pancreas and 2 without precise diagnosis in the stomach. One leiomyoma in the duodenum. From the 11 SMT initially suspected by endoscopy which showed an integrity of the wall there were 10 extrinsic compressions and 1 without pathological findings. To date, surgery was performed on 22 patients with SMT complicated with ulcer and/or hemorrhage and on those larger than 3 cm with an ecogenic pattern, suspected of malignancy. Thirteen gastric leiomyomas, 2 gastric lipomas and 1 ectopic pancreas, with a 100% correlation in the postresection histological studies, 2 Abricosoff tumors of the esophagus, 2 leiomyosarcomas with 100% correlation and a giant lipoma of the esophagus which resulted in a liposarcoma, and 1 leiomyoma which resulted in a leiomyosarcoma were found. According to these results 90% diagnostic specificity and 100% sensitivity make this imaging technique the ideal method to evaluate these lesions and one of the main indications together with the staging of gastrointestinal tumors.

Adolescent↗
PubMed1994

A locus involved in the regulation of replication in plasmid pSC101.

The origin of replication of plasmid pSC101 contains three directly repeated sequences RS1, RS2, and RS3 separated by 22 bp from two palindromic sequences, IR1 and IR2, which are partially homologous to the direct repeats. These inverted repeat (IR) sequences overlap the promoter of the repA gene which encodes a protein essential for plasmid replication. We have shown that RepA binds to the RS sites as a monomer and to the IR sites as a dimer. The influence of the IR1 site, and of the DNA segment that separates it from RS3, on plasmid copy number control has been studied in detail. We show that the integrity of IR1 is essential for efficient replication and plasmid stability, the critical site extending to the left of IR1 proper. We also show that the presence of IR1 modifies profoundly the binding properties of purified RepA protein to a segment of DNA containing the RS sequences. IR1 is separated from its homologous site on RS3 by approximately four turns of the DNA helix. Replication is abolished if this distance is increased by half a turn of the helix but it is restored if the distance is increased by a whole turn. These results suggest a DNA looping interaction, in the initiation of replication, between the RepA dimer that binds IR1 and the RepA monomers that bind the RS sequences.

Base Sequence↗
PubMed1993

Lesion-induced expression of low-affinity nerve growth factor receptor-immunoreactive protein in Purkinje cells of the adult rat.

Normal adult cerebellar Purkinje cells in the rat rarely express low-affinity nerve growth factor receptor immunoreactivity. However, intense anti-low-affinity nerve growth factor receptor immunostaining was observed as early as one day after a lesion of the cerebellar cortex. Low-affinity nerve growth factor receptor immunoreactivity was confined to a selected group of Purkinje cells, the number of which reached a maximum at three days postlesion, and, in some neurons, persisted up to 10 days after damage. The intensity of Purkinje cell immunolabeling decayed abruptly with distance from the lesion site. Reactive Purkinje cells exhibited deposition of immunoreaction product in the cell soma, dendrites and axons. Characteristically, most Purkinje cell axons exhibiting intense low-affinity nerve growth factor receptor immunoreactivity had beaded, varicose morphology. Varicose fibres with the appearance of recurrent collaterals of Purkinje cell axons were also low-affinity nerve growth factor receptor-positive. Our results indicate that adult rat Purkinje cells increase low-affinity nerve growth factor receptor-immunoreactive protein in response to injury, suggesting that, in the cerebellum, low-affinity nerve growth factor receptor or low-affinity nerve growth factor receptor-like molecules may be involved in regulating neuronal plasticity during adulthood.

Animals↗
PubMed1993

In vivo and in vitro studies of a copy number mutation of the RepA replication protein of plasmid pSC101.

The RepA replication protein of plasmid pSC101 binds as a monomer to three repeated sequences (RS1, RS2, and RS3) in the replication origin of the plasmid to initiate duplication and binds as a dimer to two inversely repeated sequences (IR1 and IR2) in its promoter region (D. Manen, L. C. Upegui-Gonzalez, and L. Caro, Proc. Natl. Acad. Sci. USA 89:8923-8927, 1992). The binding to IR2 autoregulates repA transcription (P. Linder, G. Churchward, G. X. Xia, Y. Y. Yu, and L. Caro, J. Mol. Biol. 181:383-393, 1985). A mutation in the protein RepA(cop) that affects a single amino acid increases the plasmid copy number fourfold. In vivo experiments show that, when provided in trans under a foreign promoter, the RepA(cop) protein increases the replication of a plasmid containing the origin of replication without repA, whereas it decreases the repression of its own promoter. In vitro experiments show that the purified RepA(cop) protein binds more efficiently to the repeated sequences within the origin than does RepA and that its binding to these sequences is more specific than that of RepA. Binding to an inversely repeated sequence within the repA promoter gives opposite results: the wild-type protein binds efficiently to that sequence, whereas the mutated protein binds less efficiently and less specifically. Footprint experiments confirmed these results and, in addition, showed a difference in the pattern of protection of the inversely repeated sequences by the mutant protein. Equilibrium binding experiments showed that the formation of protein-probe complexes at increasing concentrations of protein had a sigmoidal shape for binding to RS sequences and a hyperbolic shape for binding to IR sequences. The results, together with earlier work (G.-X. Xia, D. Manen, T. Goebel, P. Linder, G. Churchward, and L. Caro, Mol. Microbiol. 5:631-640, 1991), confirm that the binding of RepA to RS sequences plays a crucial role in the regulation of plasmid replication and that its binding to IR sequences plays a role in the autoregulation of RepA expression. They also demonstrate that the two separate functions of the protein are effected by two different forms of binding to the target sites.

Amino Acid Sequence↗
PubMed1992

Monomers and dimers of the RepA protein in plasmid pSC101 replication: domains in RepA.

The replication of plasmid pSC101 requires the plasmid-encoded protein RepA. This protein has a double role: it binds to three directly repeated sequences in the pSC101 origin and promotes replication of the plasmid; it binds to two inversely repeated sequences in its promoter region and regulates its own transcription. A series of RepA protein derivatives carrying deletions of the C-terminal region were assayed for specific binding. We found that the last third of the protein is not needed for binding to the various specific sites. Truncated proteins that still bind can also form heterodimers with a wild-type protein. Analysis of band retardation assays conducted with wild-type and truncated proteins indicates that RepA binds to directly repeated sequences as a monomer and to inversely repeated sequences as a dimer.

Bacterial Proteins↗
PubMed1991

A copy-number mutant of plasmid pSC101.

Copy-number mutants of plasmid pSC101 were isolated by u.v. mutagenesis and selection for elevated expression of ampicillin resistance. Three independent mutations were identical and mapped in codon 93 of the initiation protein RepA. The mutated plasmids were maintained at a level four to five times higher than that of the wild type. For one of them, it was determined that: (i) the mRNA of the autoregulated repA gene, cloned onto a pUC19 plasmid under the control of its own promoter, was expressed at a level 1.7 times higher than that of the wild type; (ii) the RepA protein, under the same conditions, was expressed at a similarly higher level; (iii) the affinity of the mutated protein for three repeated sequences in the origin region of the plasmid was, on average, 3.4 times higher than that of the wild-type protein. We postulate that the copy-number effect is due to a combination of these two effects, i.e. higher protein concentration and increased affinity of the protein for the repeated sequences.

Ampicillin Resistance↗
PubMed1991

The replication of plasmid pSC101.

The origin of replication of plasmid pSC101 presents features reminiscent of those found in a number of plasmids. As for those plasmids, many details about the way it initiates its replication are beginning to be known, but the regulation of this process will not be easily understood.

Bacterial Proteins↗
PubMed1990

The par region of pSC101 affects plasmid copy number as well as stability.

The par locus is a segment of pSC101 that has been identified as a cis-acting determinant of plasmid stability. We show that par also determines copy number and must, therefore, play a role in plasmid replication. The segregation defect, but not the copy-number reduction, of par- replication origins is completely suppressed by a short sequence from the bacteriophage lambda gene O which is present in plasmid pKO-4. Thus, replication and segregation functions are separable from each other.

Ampicillin Resistance↗
PubMed1989

Transcription events in the origin of replication of plasmid pSC101.

Insertion mutations were isolated in the origin fragment of the plasmid pSC101 after random cleavage with DNase I. The replication properties of the resulting plasmids confirmed previous findings and extended the characterization of the essential regions. Using these plasmids, we analyzed by various methods the transcription events in the pSC101 origin. In addition to the mRNA of repA, a gene coding for the self-regulated RepA protein which is essential for replication of the plasmid, we characterized a transcript, which we called RNA Y, that runs in the opposite direction and that starts in the middle of the second repeated sequence in the origin region. Like the self-regulated repA mRNA, RNA Y is weakly expressed. It does not code for a complete protein within the origin fragment but may do so in the wild-type plasmid. We also found indications for one or, possibly, two small RNA species, called RNA X, which run in the same direction as RepA and which are partially complementary to RNA Y. We postulate that RNA Y and, possibly, RNA X are implicated in the initiation of replication of pSC101.

Base Sequence↗
PubMed1986

Replication of pSC101: effects of mutations in the E. coli DNA binding protein IHF.

We have shown that the plasmid pSC101 is unable to be maintained in strains of E. coli carrying deletions in the genes himA and hip which specify the pleitropic heterodimeric DNA binding protein, IHF. We show that this effect is not due to a modulation of the expression of the pSC101 RepA protein, required for replication of the plasmid. Inspection of the DNA sequence of the essential replication region of pSC101 reveals the presence of a site, located between the DnaA binding-site and that of RepA, which shows extensive homology with the consensus IHF binding site. The proximity of the sites suggests that these three proteins, IHF, DnaA, and RepA may interact in generating a specific DNA structure required for initiation of pSC101 replication.

Amino Acid Sequence↗
PubMed1985

An essential replication gene, repA, of plasmid pSC101 is autoregulated.

Measurements of the rate of replication of a mutant pSC101 plasmid, cloned into a ColE1 vector, showed that insertions of the transposon Tn1000 into the repA gene of pSC101 abolished replication activity, but could be complemented in trans, albeit at a low level. The promoter of the repA gene was mapped by the construction of repA-lacZ gene fusions, and one of the fusions was used to demonstrate that repA protein, provided in trans, could repress expression of beta-galactosidase activity. This repression was primarily due to reduction of transcription of the repA-lacZ fusion. The sequence analysis of mutants of the repA-lacZ fusion gene which were no longer sensitive to the presence of repA protein showed that the site of action of repA was a 22 base-pair sequence, present as an inverted repeat, overlapping the repA promoter. The repA gene is thus autoregulated.

Bacterial Proteins↗