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Patricia García

Publications and source records attributed to Patricia García.

18 recordsLinked to original sources
PubMed2006

Role of Rho GTPases and Rho-GEFs in the regulation of cell shape and integrity in fission yeast.

The Rho family of GTPases are highly conserved molecular switches that control some of the most fundamental processes of cell biology, including morphogenesis, vesicular transport, cell division and motility. Guanine nucleotide-exchange factors (GEFs) are directly responsible for the activation of Rho-family GTPases in response to extracellular stimuli. In fission yeast, there are seven Dbl-related GEFs and they activate six Rho-type GTPases within a particular spatio-temporal context. The failure to do so might have consequences reflected in aberrant phenotypes and in some cases lead to cell death. In this review, we briefly summarize the role of Rho GTPases and Rho-GEFs in the establishment and maintenance of cell polarity and cell integrity in Schizosaccharomyces pombe.

Cell Polarity↗
PubMed2006

[Presence of Bartonella henselae in cats: natural reservoir quantification and human exposition risk of this zoonoses in Chile].

BACKGROUND: The availability of a serologic test for cat scratch disease in humans has allowed the diagnosis of an increasing number of cases of this disease in Chile. AIM: To perform a serological survey for Bartonella henselae among cats in Chile. MATERIAL AND METHODS: Blood samples from 187 cats living in three Chilean cities were obtained. IgG antibodies against Bartonella henselae were measured using indirect immunofluorescence. Blood cultures were done in 60 samples. The presence of Bartonella henselae in positive cultures was confirmed by restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR). RESULTS: The general prevalence of IgG antibodies against Bartonella henselae was 85.6%. No differences in this prevalence were found among cats younger or older than 1 year, or those infested or not infested with fleas. However domestic cats had a lower prevalence when compared with stray cats (73 and 90% respectively, p <0.01). Bartonella henselae was isolated in 41% of blood cultures. All the isolated were confirmed as Bartonella henselae by RFLP-PCR. CONCLUSIONS: This study found an important reservoir of Bartonella henselae in Chilean cats and therefore a high risk of exposure in humans who have contact with them.

Animals↗
PubMed2006

Rgf1p is a specific Rho1-GEF that coordinates cell polarization with cell wall biogenesis in fission yeast.

Rho1p regulates cell integrity by controlling the actin cytoskeleton and cell wall synthesis. We have identified a new GEF, designated Rgf1p, which specifically regulates Rho1p during polarized growth. The phenotype of rgf1 null cells was very similar to that seen after depletion of Rho1p, 30% of cells being lysed. In addition, rgf1(+) deletion caused hypersensitivity to the antifungal drug Caspofungin and defects in the establishment of bipolar growth. rho1(+), but none of the other GTPases of the Rho-family, suppressed the rgf1Delta phenotypes. Moreover, deletion of rgf1(+) suppressed the severe growth defect in rga1(+) null mutants (a Rho1-GAP, negative regulator). Rgf1p and Rho1p coimmunoprecipitated and overexpression of rgf1(+) specifically increased the GTP-bound Rho1p; it caused changes in cell morphology, and a large increase in beta(1,3)-glucan synthase activity. These effects were similar to those elicited when the hyperactive rho1-G15V allele was expressed. A genetic relationship was observed between Rgf1p, Bgs4p (beta[1,3]-glucan synthase), and Pck1p (protein kinase C [PKC] homologue); Bgs4p and Pck1p suppressed the hypersensitivity to Caspofungin in rgf1Delta mutants. Rgf1p localized to the growing ends and the septum, where Rho1, Pck1p, and Bgs4p are known to function. Our results suggest that Rgf1p probably activates the Rho functions necessary for coordinating actin deposition with cell wall biosynthesis during bipolar growth, allowing the cells to remodel their wall without risk of rupture.

Amino Acid Sequence↗
PubMed2005

[National consensus for management of community acquired pneumonia in adults].

Community acquired pneumonia (CAP) is an acute respiratory infection that affects pulmonary parenchyma, and is caused by community acquired microorganisms. In Chile, pneumonia represents the main cause of death due to infectious diseases and is the third specific cause of mortality in adults. In 1999, an experts committee in representation of "Sociedad Chilena de Enfermedades Respiratorias", presented the first National Guidelines for the Treatment of Adult Community Acquired Pneumonia, mainly based in foreign experience and documents, and adapted it to our National Health System Organization. During the last decade, impressive epidemiological and technological changes have occurred, making the update of guidelines for treatment of NAC by several international scientific societies, necessary. These changes include: new respiratory pathogens that are being identified in CAP and affect adult patients (Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella pneumophila); the increasing senescent adult population that carries multiple co-morbidities; the emergence of antimicrobial resistance among respiratory pathogens associated to massive antibiotic prescription; the development by the pharmaceutical industry of new drugs that are effective for pneumonia treatment (macrolides, ketolides and respiratory fluorquinolones); and the development of new diagnostic techniques for detection of antigens, antibodies, and bacterial DNA by molecular biology, useful in respiratory infections. Based on these antecedents, an Advisory Committee of "Sociedad Chilena de Enfermedades Respiratorias" and "Sociedad Chilena de Infectología" has reviewed the national and international evidence about CAP management in adults in order to update clinical recommendations for our country.

Acute Disease↗
PubMed2005

[Necrotizing pneumonia due to Rhodococcus equi in non HIV immunocompromised host. Case report and review].

Rhodococcus equi, is a grampositive intracellular bacillus, that causes infection mainly in immunocompromised hosts. We report the case of a 52 years old woman, with a systemic lupus erythematosus and a progressive 10 months evolution with cough, dyspnea, mucous-purulent sputum, occasionally hemoptysis, intermittent fever, and weight loss of 10%. With partial response to antibiotic treatment, radiological evolution of thoracic scanners evidenced the development of multiple bilateral areas of consolidation, some of them nodular. Percutaneous thoracic biopsy showed characteristic histology and microbiological analysis yielded the identification of Rhodococcus equi in both bronchoalveolar lavage and pulmonary biopsy. She received prolonged bi-associated antibiotic treatment with good clinical and radiological response. This agent must be considered in the study of immunocompromised patients that present with a prolonged evolution of pneumonia.

Actinomycetales Infections↗
PubMed2005

[Utility of stool culture in inpatient].

Several studies have concluded that it is inappropriate to perform stool cultures (SC) to inpatients that have stayed hospitalized three days or more because nosocomial diarrhea is not due to enteric pathogenic bacteria that are searched through this exam. The aim of this paper was to analyze the SC yield performed to patients hospitalized in the UC Health Net since January to December 2002 and the rate of positive results obtained depending on the length of hospitalization in order to define if international guidelines are useful to the national reality. During twelve months 3474 SC were evaluated, 458 (13.2%) belonged to inpatients. Of them 16 (3.5%) were positive, 13 were obtained on the first day, 2 at the second day and 1 at the fifth day of hospitalization. Only 1/190 (0.5) SC obtained after two days of hospitalization yielded a positive result. These results reinforce the international recommendation of not performing SC to inpatients that have stayed more than three days at the hospital; besides, considering previous figures, we suggest to make a cutoff at day two of hospitalization, after two days there is no a significant clinical impact. This strategy means to reduce 41% of these analyses and to save the corresponding money.

Adolescent↗
PubMed2004

Schizosaccharomyces pombe Rgf3p is a specific Rho1 GEF that regulates cell wall beta-glucan biosynthesis through the GTPase Rho1p.

Rho1p regulates cell integrity by controlling the actin cytoskeleton and cell-wall synthesis. Here, we describe the cloning and characterization of rgf3+, a member of the Rho family of guanine nucleotide exchange factors (Rho GEFs). The rgf3+ gene was cloned by complementation of a mutant (ehs2-1) hypersensitive to drugs that interfere with cell-wall biosynthesis. The rgf3+ gene was found to be essential for cell viability and depletion of Rgf3p afforded phenotypes similar to those obtained following depletion of Rho1p. However, the cell death caused by Rgf3p depletion could be rescued by the presence of 1.2 M sorbitol, whereas depletion of Rho1 was lethal under the same conditions. We show that Rgf3p is a specific Rho1-GEF. The hypersensitivity to drugs affecting the cell wall of the ehs2-1 mutant was suppressed by overexpression of rho1+ but not by any of the other GTPases of the Rho family. Rgf3p interacted with the GDP-bound form of Rho1p and promoted the GDP-GTP exchange. In addition, we show that overexpression of Rgf3p produces multiseptated cells and increases beta-1,3-glucan synthase activity and the amount of cell wall beta-1,3-glucan. Rgf3p localized to the septum and the mRNA level was regulated in a cell-cycle-dependent manner peaking during septation. Our results suggest that Rgf3p acts as a positive activator of Rho1p, probably activating the Rho functions that coordinate cell-wall biosynthesis to maintain cell integrity during septation.

Amino Acid Sequence↗
PubMed2004

Coagulase-negative staphylococci: clinical, microbiological and molecular features to predict true bacteraemia.

Coagulase-negative staphylococci (CNS) are frequently isolated from blood cultures, where they may be only a contaminant or the cause of bacteraemia. Determining whether an isolate of CNS represents a true CNS bacteraemia is difficult, and there is no single criterion with sufficient specificity. The aim of this study was to assess those clinical, microbiological, pathogenic and genotypic features that characterize true CNS bacteraemia. Twenty patients having two or more blood cultures positive for CNS and 20 patients with only one positive blood culture were studied. Significant bacteraemia was defined according to clinical and laboratory criteria. Incubation time for blood cultures to become positive, macroscopic appearance of colonies, species determination, biotype, susceptibility to antimicrobials, PFGE pattern and adherence capacity were all studied. Clinical bacteraemia was present in 16/20 patients with two or more positive blood cultures and in 2/20 patients with only one positive blood culture. A significant difference was seen in the median time to positivity between the 18 clinical bacteraemias and 22 contaminations (23.6 versus 29.2 h; P = 0.04, Wilcoxon). There was also a significant difference between the two groups in the median absorbance of the slime test (1.36 versus 0.58; P = 0.005). All significant bacteraemias with two or more positive blood cultures had the same species identified, the same antimicrobial susceptibility pattern and the same PFGE pattern. In two patients with true bacteraemia with only one positive blood culture, the incubation time for the culture to turn positive was <24 h and the slime production absorbance was >2.5. The most useful parameters for the diagnosis of true CNS bacteraemia for patients with two positive blood cultures were incubation time until positive, species identification, antimicrobial susceptibility pattern, slime production and PFGE pattern. For patients with only one blood culture positive for CNS, the useful parameters for prediction of true bacteraemia were incubation time until positive and slime production, both of which are simple, low-cost tests.

Bacteremia↗
PubMed2004

[Influenza-A as etiology of fever and respiratory insufficiency in adults hospitalized during an outbreak in Chile].

BACKGROUND: Influenza-A (IA) occurs every winter, is mostly observed among outpatients. AIM: To describe the clinical and epidemiological characteristics of cases that required hospital admission during an outbreak in Chile in 1999. PATIENTS AND METHODS: Adults subjects, with Influenza A confirmed by antigen detection test, hospitalized in the clinical hospital of the "Hospital Clínico de la Universidad Católica de Chile" between May and June, with fever or respiratory symptoms were studied. A special record was designed to register clinical, microbiological and therapeutic data. RESULTS: Fifty five cases, 26 males, aged 15 to 91 years, were studied. Eighty four percent had chronic concomitant diseases and 9.1% were immunosuppressed. Clinical findings were fever in 873%, asthenia in 83.6%, cough in 93.6%, abnormal pulmonary signs in 69%, an elevated C-reactive protein (mean value of 11.6 +/- 7.1 mg/dL) and acute respiratory insufficiency in 54.5%. Cases were isolated in cohort or individual rooms and 38.2% were admitted to intensive or intermediate care units. Amantadine was prescribed to 52 patients and was well tolerated. Thirty three percent of cases developed pneumonia. These subjects were older; had more dyspnea and respiratory insufficiency than patients without pneumonia. CONCLUSIONS: IA should be borne in mind when dealing with hospitalized adults, during epidemic outbreaks in the community. The clinical picture can resemble a serious bacterial infection. An early diagnosis allows the use of specific treatments, to decrease the risk of nosocomial spread and to avoid unnecessary use of antibiotics.

Adolescent↗
PubMed2003

Identification and characterization of three novel cold acclimation-responsive genes from the extremophile hair grass Deschampsia antarctica Desv.

Deschampsia antarctica Desv. is the only monocot that thrives in the harsh conditions of the Antarctic Peninsula and represents an invaluable resource for the identification of genes associated with freezing tolerance. In order to identify genes regulated by low temperature, we have initiated a detailed analysis of its gene expression. Preliminary 2-D gels of in vivo-labeled leaf proteins showed qualitative and quantitative differences between cold-acclimated and non-acclimated plants, suggesting differential gene expression. Similarly, cold-acclimation-related transcripts were screened by a differential display method. Of the 38 cDNAs initially identified, three cDNA clones were characterized for their protein encoding, expression pattern, response to several stresses, and for their tissue-specific expression. Northern blot analysis of DaGrx, DaRub1, and DaPyk1 encoding a glutaredoxin, a related-to-ubiquitin protein, and a pyruvate kinase-like protein, respectively, showed a distinct regulation pattern during the cold-acclimation process, and in some cases, their cold response seemed to be tissue specific. All three transcripts seem to be responsive to water stress as their levels were up-regulated with polyethyleneglycol treatment. DaRUB1 and DaPyk1 expression was up-regulated in leaf and crown, but down-regulated in roots from cold-acclimated plants. The significance of these results during the cold-acclimation process will be discussed.

Acclimatization↗
PubMed2003

Saccharomyces cerevisiae fungemia after Saccharomyces boulardii treatment in immunocompromised patients.

Saccharomyces cerevisiae is widely used as a probiotic compound. Clinical data suggest that this agent is safe and effective. We report two cases of fungemia caused by S. cerevisiae occurring in immunosuppressed patients treated orally with S. boulardii Molecular typing confirmed clonality in isolate strains from patients and the capsule. Physicians caring for immunosuppressed patients must be aware of this potential serious complication of probiotic use.

Adult↗
PubMed2003

[Community acquired pneumococcal pneumonia in hospitalized adult patients].

BACKGROUND: S pneumoniae is the most common cause of community-acquired pneumonia. AIM: To evaluate the clinical characteristics, antibiotic resistance, management and prognostic factors in pneumococcal pneumonia. METHODS: Prospective evaluation in 46 adults (age +/- sd: 68 +/- 17 years) hospitalized with pneumococcal pneumonia confirmed by sputum, blood or pleural fluid cultures. Clinical and radiographic variables, risk factors for antibiotic resistance, and hospital mortality rate were recorded. RESULTS: Heart disease (39%), COPD/asthma (25%), and diabetes mellitus (18%) were the most frequent underlying diseases. None of the patients had previously received pneumococcal vaccine. Only 17% of the patients had the classic triad of chills, fever and productive cough. At admission, interestingly, 17% presented with congestive heart failure. Resistance of pneumococci to penicillin, cefotaxime or erythromycin was 15%, 6% and 11%, respectively. Antibiotic use prior to admission was significantly associated with antibiotic resistance (OR = 6; CI 95% = 1.1-32; p < 0.05). Fifty per cent of the patients were admitted to intermediate or intensive care units, 15% were mechanically ventilated, 20% developed septic shock, 20% developed acute renal failure and 13% died in the hospital. Clinical factors significantly associated with higher mortality were systolic hypotension (< or = 90 mmHg), ICU admission and BUN > 30 mg per dL. CONCLUSIONS: Our data suggest that pneumococcal pneumonia is still a severe infection with high mortality; hence, efforts should be made at prevention using pneumococcal immunization.

Adolescent↗
PubMed2002

Acute community-acquired pneumonia in adults: guidelines for initial antimicrobial therapy based on local evidence from a South American Working Group (ConsenSur).

Community-acquired pneumonia (CAP) is probably one of the infections affecting ambulatory patients for which the most diverse guidelines have been written worldwide. Most guidelines agree that antimicrobial therapy should be initially tailored according to either the severity of the infection or the presence of co-morbidity and epidemiology. Nevertheless, a great variability may be noted among different countries in the selection of first choice antimicrobial agents, even for cases considered as low-risk. This may be due to the many microbial causes of CAP and specialties involved, as well as different healthcare systems which affect the availability or cost of antibiotics. However, many countries or regions adopt some of the guidelines or design their own recommendations, regardless of the local data, probably because of the scarcity of such data. A committee composed of South American infectious diseases specialists and microbiologists, with strong interest and recognized experience in CAP, were convened to establish a working group (ConsenSur) for designing a local evidence-based practice guideline for the initial management of CAP. This supplement is intended to give a practice recommendation for the initial antimicrobial treatment of CAP upon the basis of local evidence, in the hope of procuring a suitable tool for use by the different health-care providers concerned with the management of this infection in South America or in other countries where the main considerations for CAP are comparable.

Acute Disease↗