Biomedical subjects

J A García

Publications and source records attributed to J A García.

At least 19 recordsLinked to original sources

PubMed2006

Identification of a plum pox virus CI-interacting protein from chloroplast that has a negative effect in virus infection.

The cylindrical inclusion (CI) protein of potyviruses is involved in virus replication and cell-to-cell movement. These two processes should rely on multiple plant-virus interactions; however, little is known about the host factors that are involved in, or that may interfere with, CI functions. By using a yeast two-hybrid system, the CI protein from Plum pox virus (PPV) was found to interact with the photosystem I PSI-K protein, the product of the gene psaK, of Nicotiana benthamiana. Coexpression of PPV CI was shown to cause a decrease in the accumulation level of PSI-K transiently expressed in N. benthamiana leaves. To test the biological relevance of this interaction, we have analyzed the infection of PPV in N. benthamiana plants in which psaK gene expression has been silenced by RNA interference, as well as in Arabidopsis thaliana psaK knockout plants. Our results show that downregulation of the psaK gene leads to higher PPV accumulation, suggesting a role for the CI-PSI-K interaction in PPV infection.

Chloroplasts↗

PubMed2006

Multiple resistance traits control Plum pox virus infection in Arabidopsis thaliana.

Twelve Arabidopsis accessions were challenged with Plum pox potyvirus (PPV) isolates representative of the four PPV strains. Each accession supported local and systemic infection by at least some of the PPV isolates, but high variability was observed in the behavior of the five PPV isolates or the 12 Arabidopsis accessions. Resistance to local infection or long-distance movement occurred in about 40% of all the accession-isolate combinations analyzed. Except for Nd-1, all accessions showed resistance to local infection by PPV-SoC; in the Landsberg erecta (Ler) accession, this resistance was compromised by sgt1 and rar1 mutations, suggesting that it could be controlled by an R gene-mediated resistance pathway. While most of the susceptible accessions were symptomless, PPV induced severe symptoms on inflorescences in C24, Ler, and Bay-0 as early as 15 days after inoculation. Genetic analyses indicated that these interaction phenotypes are controlled by different genetic systems. The restriction of long-distance movement of PPV-El Amar and of another member of genus Potyvirus, Lettuce mosaic virus, in Col-0 requires the RTM genes, indicating for the first time that the RTM system may provide a broad range, potyvirus-specific protection against systemic infection. The restriction to PPV-PS long-distance movement in Cvi-1 is controlled by a single recessive gene, designated rpv1, which was mapped to chromosome 1. The nuclear inclusion polymerase b-capsid protein region of the viral genome appears to be responsible for the ability of PPV-R to overcome rpv1-mediated resistance.

Arabidopsis↗

PubMed2006

Increasing the amount of n-3 fatty acid in meat from young Holstein bulls through nutrition.

Fifty-four Holstein bulls were blocked by initial BW (301 +/- 7.4 kg) and randomly assigned to 6 treatments following a 3 x 2 factorial arrangement, with 3 concentrate lipid levels (5, 8, and 11% of DM) and 2 lipid sources (whole canola seed and whole linseed), with the objective of evaluating the possibility of increasing the content of n-3 fatty acids in meat. Concentrates (mostly corn meal) were isonitrogenous and isocaloric. Concentrate and straw were both fed ad libitum. Animal BW was recorded every 2 wk, and feed consumption was recorded weekly. Ruminal pH and VFA concentrations were determined monthly. Bulls were transported to the slaughterhouse when they achieved the target slaughter weight of 443 kg (after 105 +/- 4 d of fattening). After slaughter, a sample of LM from the sixth to the eighth ribs was dissected and analyzed for intramuscular fat content and fatty acid profile. Dietary lipid source did not affect overall animal performance, rumen fermentation, or carcass quality. Rumen pH was >6.0 despite consumption by the bulls of large amounts of concentrate. In bulls fed linseed, the percentage of n-3 fatty acids in LM increased linearly with lipid level, whereas in bulls fed canola seed it remained constant. The ratio of n-6:n-3 fatty acids was lower (P < 0.01) in the LM of bulls fed linseed (10.0) than in those fed canola seed (26.0). The content of cis-9, trans-11-CLA in the LM tended (P = 0.06) to be greater in the bulls fed linseed than in those fed canola seed (62.9 vs. 49.2 mg/kg of LM, respectively). Concentration of n-3 fatty acids in meat of bulls fed high-concentrate diets can be enhanced by whole linseed supplementation without affecting animal performance, ruminal fermentation, or carcass quality.

Animal Feed↗

PubMed2005

Trypanosoma vivax: a novel method for purification from experimentally infected sheep blood.

Trypanosoma vivax is the principal etiological agent of bovine trypanosomosis, a widely disseminated disease in tropical and subtropical regions. Here, we present a simple and reproducible method for the purification of T. vivax from experimentally infected and immunosuppressed sheep, using an isopycnic Percoll gradient, followed by DEAE-cellulose chromatography, with an estimated yield of 11-15%. This method could be used for the purification of T. vivax geographical isolates from various locations and from different natural hosts.

Animals↗

PubMed2005

Anti-CD25 monoclonal antibody sequential immunosuppressive induction therapy in renal transplants with high risk of delayed graft function.

There is little experience on the use of monoclonal antibodies that block the high-affinity interleukin-2 receptor (basiliximab and daclizumab) in sequential therapy in renal transplants with risk of delayed graft function. This study sougth to test the efficacy and safety of the substitution of anticalcineurins with two doses of basiliximab or daclizumab in the immediate posttransplant period for recipients at risk of delayed renal graft function. Immunosuppression consisted of steroids, mycophenolate mofetil, and two doses of basiliximab (20 mg/day) on days 0 and 4 posttransplant or daclizumab (1 mg/kg per day) on days 0 and 15 posttransplant. Anticalcineurins were not administered until the beginning of graft function. Among 49 recipients (mean age 63.5 +/- 10.5 years), 40 received a kidney from a donor over 60 years of age, three from a non-heart-beating donor, and six from donors with an acute elevation of serum creatinine to 2.4 +/- 0.86 (1.7-3.7). At a mean follow-up of 14.2 +/- 8.4 months, five patients experienced acute rejection episodes. Only 15 patients needed posttransplant dialysis (2.7 +/- 1.6). In 11 patients, cyclosporine (CsA) was introduced at 6 +/- 2.9 days posttransplant and in 37, tacrolimus on 8.6 +/- 3.6 days posttransplant. The incidence of kidney graft loss was 16.3%. Patient survival was 96%. Thirty-nine recipients are alive with functioning grafts, with mean serum creatinine of 1.4 mg/dL. In conclusion, substitution for anticalcineurins with interleukin-2-receptor blockade in the immediate posttransplant period for patients at risk of delayed graft function minimizes nephrotoxicity and reduces tubular necrosis, without increasing the risk of an acute rejection episode.

Adolescent↗

PubMed2005

Identification of secret agent as the O-GlcNAc transferase that participates in Plum pox virus infection.

Serine and threonine of many nuclear and cytoplasmic proteins are posttranslationally modified with O-linked N-acetylglucosamine (O-GlcNAc). This modification is made by O-linked N-acetylglucosamine transferases (OGTs). Genetic and biochemical data have demonstrated the existence of two OGTs of Arabidopsis thaliana, SECRET AGENT (SEC) and SPINDLY (SPY), with at least partly overlapping functions, but there is little information on their target proteins. The N terminus of the capsid protein (CP) of Plum pox virus (PPV) isolated from Nicotiana clevelandii is O-GlcNAc modified. We show here that O-GlcNAc modification of PPV CP also takes place in other plant hosts, N. benthamiana and Arabidopsis. PPV was able to infect the Arabidopsis OGT mutants sec-1, sec-2, and spy-3, but at early times of the infection, both rate of virus spread and accumulation were reduced in sec-1 and sec-2 relative to spy-3 and wild-type plants. By matrix-assisted laser desorption ionization-time of flight mass spectrometry, we determined that a 39-residue tryptic peptide from the N terminus of CP of PPV purified from the spy-3 mutant, but not sec-1 or sec-2, was O-GlcNAc modified, suggesting that SEC but not SPY modifies the capsid. While our results indicate that O-GlcNAc modification of PPV CP by SEC is not essential for infection, they show that the modification has a role(s) in the process.

Acylation↗

PubMed2005

[Digestive haemorrhage due to angiodysplasia in dialysis patients. Treatment with conjugated estrogens].

Gastrointestinal angiodysplasia is a very common cause of digestive hemorrhage among elderly patients with chronic renal insufficiency. Therapeutic possibilities are scarce, as well as information available. Here we present our experience with 8 cases of dialysis patients that were treated with conjugated estrogens because of digestive hemorrhage due to angiodysplasia. Dissapearance of bleeding was observed after the onset of estrogen therapy, with a significant decrease of blood transfusions. This type of non-invasive treatment can avoid aggressive therapeutic interventions in patients with a high prevalence of co-morbid conditions (old patients undergoing chronic dialysis).

Aged↗

PubMed2004

Statistical normal values of visual parameters that characterize binocular function in children.

A wide range of visual parameters used to evaluate binocular function were evaluated in a paediatric population (1056 subjects aged 6-12 years). Mean values are provided for these ages in optometric tests that directly assess the vergence system, horizontal phorias for near and far vision (measured by a modified version of the Thorington method), negative and positive vergence amplitude for near and far vision (step vergence testing), vergence facility (flippers 8 Delta BI/8 Delta BO), and near-point of convergence (penlight push-up technique and red-lens push-up technique), as well as stimulus accommodative convergence/accommodation ratio and stereoacuity (Randot test) which provide an overall evaluation of the vergence, accommodative and oculomotor systems. A statistical comparison (anova and Bonferroni post hoc test) of these values between ages was performed. The differences, although statistically significant, were not clinically meaningful, and therefore we identified two trends in the behaviour of these parameters. For all parameters, except for vergence facility, we established a single mean reference value for the age range studied. The difference between the means for vergence facility indicated the need to divide the population into two age ranges (6-8 and 8-12 years). This study establishes statistical normal values for these parameters in a paediatric population and their means are a valuable instrument for separating children with binocular anomalies from those with normal binocular vision.

Aging↗

PubMed2004

[Acute hyperphosphatemia secondary to phosphate administration for bowel preparation].

We report a 75-years-old woman, stable on a three-weekly hemodialysis program over a period of 3 years, who develop acute hyperphosphatemia secondary to phosphate administration for bowel preparation. The quick clinical diagnosis and the treatment with intensive hemodialysis resulted in a correction of hyperphosphatemia, hypocalcemia, acidemia and other electrolyte abnormalities. The phosphate cathartics are contraindicated in patients with severe renal insufficient or in dialysis program. Our case shows the severe side effects secondary to injudicious use of sodium phosphate cathartics.

Acute Disease↗

PubMed2004

[Antiproteinuric effect of renin-angiotensin system blockade in patients with normal/lower than 115 mmHg systolic blood pressure].

UNLABELLED: The renoprotective effect of renin-angiotensin system (RAAS) blockade by ACE inhibitors (ACEI) or AT1 receptor antagonists (ARA) in chronic proteinuric nephropathies is well known. Most studies have related this beneficial effect with the antihypertensive and antiproteinuric properties of these drugs, but this aspect has not been extensively analyzed in patients with normal/low values of blood pressure. We studied nineteen patients with different chronic proteinuric nephropathies that started ACEI or ARA because of proteinuria and despite systolic blood pressure (SBP) < or = 115 mmHg. Short and long-term tolerance to treatment as well as evolution of renal function parameters were recorded. RESULTS: At baseline, SBP was 110.2 +/- 2.6 mmHg (105-115) an diastolic blood pressure (DBP) 68.6 +/- 4.3 (60-75). Initial low doses of ACEI or ARA were well tolerated. After 6 months of treatment, proteinuria decreased by 46% of baseline, from 2.1 +/- 1.8 g/day to 1.1 +/- 0.8 g/day, without significant changes in BP or renal function. After a 48 +/- 27 months follow up, proteinuria decreased to 0.7 +/- 0.6 g/day (68% of basal values). Renal function and BP did not show significant changes during follow up. CONCLUSIONS: RAAS blockade by ACEI/ARA induces a significant antiproteinuric and renoprotective effect in proteinuric patients with normal/low levels of BP Initial doses of ACEI/ARA were well tolerated.

Adolescent↗

PubMed2003

Evolution of accommodative function and development of ocular movements in children.

The evolution of the accommodative function and development of ocular movement are evaluated in a non-clinical paediatric population (1056 subjects) aged 6-12 years, providing means for each age in the optometric tests that evaluate the accommodative amplitude, accommodative facility, accommodative response (lag), and saccadic movements. A comparison of these values between ages (anova) established three distinct trends in the behaviour of these parameters. The accommodative amplitude, measured by modified dynamic retinoscopy, and the evaluation of the saccadic movements by the development of ocular movements [developmental eye movement (DEM)] test showed continuous change with age. The values for monocular and binocular accommodative facility, measured by +/-2.00 D flippers, indicated the need to divide the population into two age groups (6-7 and 8-12 years). Finally, the means of accommodative response, measured by monocular estimation model (MEM) retinoscopy, and the direct observation of saccadic movement revealed no significant differences between ages, establishing a single mean reference value for the age group studied.

Accommodation, Ocular↗

PubMed2001

Protection of rabbits against rabbit hemorrhagic disease virus by immunization with the VP60 protein expressed in plants with a potyvirus-based vector.

A new plum pox potyvirus (PPV)-based vector has been constructed for the expression of full-length individual foreign proteins. The foreign sequences are cloned between the NIb replicase and capsid protein (CP) cistrons. The heterologous protein is split from the rest of the potyviral polyprotein by cleavage at the site that originally separated the NIb and CP proteins and at an additional NIa protease recognition site engineered at its amino-terminal end. This vector (PPV-NK) has been used to clone different genes, engendering stable chimeras with practical applications. We have constructed a chimera expressing high levels of jellyfish green fluorescent protein, which can be very useful for the study of PPV molecular biology. The VP60 structural protein of rabbit hemorrhagic disease virus (RHDV) was also successfully expressed by making use of the PPV-NK vector. Inoculation of extracts from VP60-expressing plants induced a remarkable immune response against RHDV in rabbits, its natural host. Moreover, these animals were protected against a lethal challenge with RHDV.

Amino Acid Sequence↗

PubMed2001

Analysis of discrimination threshold on the tritan axis.

Discrimination thresholds on the tritan axis were obtained for an extensive group of 66 stimuli: in some of the stimuli, S-cone trolands were held constant by keeping the product of the S-cone excitation level and the luminance unchanged, while in others only the luminance was changed to establish various S-cone troland values. These thresholds depended clearly on the S-cone value of the stimuli, while they remained almost constant against the retinal illumination. Thus, we noted that the excitation of the L - 2M channel had practically no influence over the discrimination threshold on the tritan axis, although this independence of delta S from L - 2M was not so obvious when the S value was high. With our data, we performed different fits, and found that the fit including the terms S, (L - 2M) and (L + M) adapted better to our results.

Adult↗

PubMed2001

Does "mainstreaming" guarantee access to care for medicaid recipients with asthma?

OBJECTIVE: Recent reforms in the federal Medicaid program have attempted to integrate beneficiaries into the mainstream by providing them with managed care options. However, the effects of mainstreaming have not been systematically evaluated. DESIGN: Cross-sectional survey. SETTING/PARTICIPANTS: A sample of 478 adult, nonelderly asthmatics followed by a large Northern California medical group. MEASUREMENTS AND MAIN RESULTS: We examined differences in self-reported access by insurance status. Compared to patients with other forms of insurance, patients covered by the state's Medicaid program (Medi-Cal) were more likely to report access problems for asthma-related care, including difficulties in reaching a health care provider by telephone, obtaining a clinic appointment, and obtaining asthma medication. Adjusting for relevant clinical and sociodemographic variables, Medi-Cal patients were more likely to report at least one access problem compared to non-Medi-Cal patients (adjusted odds ratio [AOR], 3.34; 95% confidence interval [CI], 1.43 to 7.80). Patients reporting at least one access problem were also more likely to have made at least one asthma-related emergency department visit within the past year (AOR, 4.84; 95% CI, 2.41 to 9.72). Reported barriers to care did not translate into reduced patient satisfaction. CONCLUSIONS: Within this population of Medicaid patients, the provision of health insurance and care within the mainstream of an integrated health system was no guarantee of equal access as perceived by the patients themselves.

Adult↗

PubMed2001

Pathogenicity determinants in the complex virus population of a Plum pox virus isolate.

Several subisolates were separated from a single Plum pox virus (PPV) isolate, PPV-PS. In spite of an extremely high sequence conservation (more than 99.9% similarity), different subisolates differed largely in pathogenicity in herbaceous hosts and infectivity in woody plants. The severity of symptomatology did not seem to correlate with virus accumulation. Sequence analysis and site-directed mutagenesis demonstrated that single amino acid changes in the helper component (HC) protein caused a drastic effect on virus symptoms in herbaceous hosts and notably modified virus infectivity in peach seedlings. These results indicate that HC variation might play an important role in virulence evolution of natural plant virus infections. Moreover, the analysis of Potato virus X (PVX)-HC chimeras showed that the identified HC amino acid changes had parallel effects on the severity of symptoms caused by PPV and on HC-induced enhancement of PVX pathogenicity, indicating that HC functions in potyvirus symptomatology and in synergism with other viruses have overlapping determinants.

Amino Acid Substitution↗

PubMed2001

The service patterns of a racially, ethnically, and linguistically diverse housestaff.

PURPOSE: To explore whether racial and ethnic concordance in the service patterns of residents is as disproportionate as it is among practicing physicians, and to examine the effect of residents' second-language proficiencies on these patterns. METHOD: The authors conducted a cross-sectional study of billing data from 13,681 patient visits to resident continuity clinics at a Northern California pediatric medical center between May 1998 and October 1999. For each racial or ethnic group of patients, the proportion of patient visits to race-concordant residents was compared with the proportion of visits to all residents of other races or ethnicities. Multivariate logistic regression analyses (adjusted for confounders and residents' second-language proficiency) were used to measure the concordance of race or ethnicity in patient-resident pairs. RESULTS: For all visits made to African-American, Asian, and Latino residents, the percentage of race-concordant visits exceeded the percentage of race-discordant visits for each patient group. In adjusted regression models, African-American, Asian, and Latino patients were more likely to visit residents of the same race or ethnicity. White patients were not more or less likely to visit white residents. When adjusted for residents' second-language proficiencies, Latino patients remained more likely to visit Latino residents and Asian patients remained more likely to see Asian residents. In analyses restricted to residents reporting fluency in Spanish, Latino patients were more likely to visit Latino residents. CONCLUSION: African-American, Asian, and Latino pediatric residents disproportionately served more patients from their own racial or ethnic backgrounds. This service pattern was not completely explained by physicians' second-language proficiencies. A resident's race or ethnicity may reflect a unique set of skills that is highly valued by patients or health care systems.

Child↗

PubMed2000

Pulsed-field gel electrophoriesis analyis of Aeromonas salmonicida ssp. salmonicida.

A total of 133 strains of Aeromonas salmonicida ssp. salmonicida, isolated from a wide variety of sources, were characterized by pulsed-field gel electrophoresis patterns. Sixteen profiles were demonstrated, with one profile being predominant in samples from all the countries and species of fish. Our results suggest a clonal distribution of this subspecies, with a predominant clone being responsible for most of the outbreaks worldwide.

Aeromonas↗

PubMed2000

Preservation of 5'-end integrity of a potyvirus genomic RNA is not dependent on template specificity.

Full-length in vitro transcripts of plum pox potyvirus (PPV) genomic RNA with mutations altering the number of 5'-terminal adenosine residues were able to infect Nicotiana clevelandii plants, whereas a mutant with a substitution of adenosine in position 2 by guanosine failed to infect. The genomic 5' end was template-independently repaired during in vivo RNA synthesis producing wild-type viral progeny. Putative models of replication initiation are discussed.

Mutagenesis↗