Comparative study of antimicrobial resistance of Escherichia coli strains isolated from urinary tract infection in patients from Caracas and Lima.
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Anti-Bacterial Agents↗
Biomedical subjects
A García
Publications and source records attributed to A García.
Antibiotic susceptibility of Enterobacteriaceae species isolated in Venezuela over ten years.
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Anti-Bacterial Agents↗
Regulation of Pit-1 expression by ghrelin and GHRP-6 through the GH secretagogue receptor.
GH secretagogues are an expanding class of synthetic peptide and nonpeptide molecules that stimulate the pituitary gland to secrete GH through their own specific receptor, the GH-secretagogue receptor. The cloning of the receptor for these nonclassical GH releasing molecules, together with the more recent characterization of an endogenous ligand, named ghrelin, have unambiguously demonstrated the existence of a physiological system that regulates GH secretion. Somatotroph cell-specific expression of the GH gene is dependent on a pituitary-specific transcription factor (Pit-1). This factor is transcribed in a highly restricted manner in the anterior pituitary gland. The present experiments sought to determine whether the synthetic hexapeptide GHRP-6, a reference GH secretagogue compound, as well as an endogenous ligand, ghrelin, regulate pit-1 expression. By a combination of Northern and Western blot analysis we found that GHRP-6 elicits a time- and dose-dependent activation of pit-1 expression in monolayer cultures of infant rat anterior pituitary cells. This effect was blocked by pretreatment with actinomycin D, but not by cycloheximide, suggesting that this action was due to direct transcriptional activation of pit-1. Using an established cell line (HEK293-GHS-R) that overexpresses the GH secretagogue receptor, we showed a marked stimulatory effect of GHRP-6 on the pit-1 -2,500 bp 5'-region driving luciferase expression. We truncated the responsive region to -231 bp, a sequence that contains two CREs, and found that both CREs are needed for GHRP-6-induced transcriptional activation in both HEK293-GHS-R cells and infant rat anterior pituitary primary cultures. The effect was dependent on PKC, MAPK kinase, and PKA activation. Increasing Pit-1 by coexpression of pCMV-pit-1 potentiated the GHRP-6 effect on the pit-1 promoter. Similarly, we showed that the endogenous GH secretagogue receptor ligand ghrelin exerts a similar effect on the pit-1 promoter. These data provide the first evidence that ghrelin, in addition to its previously reported GH-releasing activities, is also capable of regulating pit-1 transcription through the GH secretagogue receptor in the pituitary, thus giving new insights into the physiological role of the GH secretagogue receptor on somatotroph cell differentiation and function.
Animals↗
Mycobacterium avium infection in an ostrich (Struthio camelus).
Acid-fast organisms were identified by histopathology of granulomatous lesions in an ostrich (Struthio camelus). The organisms were grown in Herrold's egg media with and without mycobactin and identified as Mycobacterium avium. An agar gel immunodiffusion (AGID) test for Mycobacterium avium paratuberculosis was performed for detection of antibody for M. avium in this infected ostrich and seven other ostriches that were in contact. The results of the AGID were consistent with the pathologic diagnosis of mycobacteriosis and the isolation of M. avium in the affected ostrich.
Animals↗
Evaluation of a Triatoma infestans elimination program by the decrease of Trypanosoma cruzi infection frequency in children younger than 10 years, Chile, 1991-1998.
Chagas disease is widespread in Chile, distributed in rural and periurban areas in the 7 most northern regions of the country. The principal vector of Trypanosoma cruzi is Triatoma infestans. The interruption of the domestic cycle of transmission of T. cruzi has been attempted by health education, human housing improving, and elimination of the vector by means of systematic insecticide spraying of human dwellings. Spraying with insecticides has been supported by Chile's health authorities and has been carried out for the last 12 years. A total of 13,280 children (aged up to 10 years) were randomly selected from 47 counties in the area of Chile endemic for Chagas disease, and blood samples were collected to determine the levels of antibodies to T. cruzi by indirect hemagglutination and enzyme-linked immunosorbent assay tests. The results of the tests were analyzed to determine the changes that occurred after 12 years of insecticide spraying of dwellings to eliminate T. infestans infestation. A total of 142 (1.1%) samples of children showed antibodies to T. cruzi. This rate is significantly lower than the data generated in similar studies conducted in 1982-1985. The following reduction in prevalence rates were observed in each of the 7 endemic regions of the country: region I, 5.5-0.3%; region II, 6.6-0.3%; region III, 9.8-1.0%; region IV, 7.2-2.0%; region V, 5.2-1.9%, Metropolitan region, 1.4-0.6%; and region VI, 1.4-0.4%. Serovigilance of T. cruzi antibodies level represents a novel approach that may allow the evaluation of the impact of the vector elimination program. The results identify regions that need to strengthen the efforts to reduce the insect infestation of dwellings.
Animals↗
Effect of internal carotid artery occlusion on vertebral artery blood flow: a duplex ultrasonographic evaluation.
The aim of this study was to evaluate the effect of unilateral internal carotid artery occlusion on blood flow volume and blood flow velocities in both vertebral arteries using duplex Doppler ultrasonography in the cervical segment. Forty patients with unilateral extracranial internal carotid artery occlusion confirmed by angiography were studied, and the results were compared with those obtained in 57 age-matched patients in whom cervical duplex ultrasonography showed no abnormalities. We measured the diameter, flow velocities, and blood flow volume in both vertebral arteries, and the side-to-side differences were also calculated. Eleven patients (27.5%) with an occluded internal carotid artery had increased peak systolic velocity in the ipsilateral vertebral artery, and 6 (15%) had increased peak systolic velocity in the contralateral vertebral artery. The mean peak systolic velocity and the mean blood flow volume were statistically greater in the ipsilateral vertebral arteries than in the same-side vertebral arteries of the control group (P < .05). We also detected a mean increase of 14.29% of the net blood flow volume in the vertebral arteries compared with the control group. Patients with extracranial unilateral internal carotid artery occlusion may have a compensatory increase in both the peak systolic velocity and the blood flow volume in both vertebral arteries.
Aged↗
Evidence that a single exposure to aversive stimuli triggers long-lasting effects in the hypothalamus-pituitary-adrenal axis that consolidate with time.
Because of its use as a negative reinforcer in animal studies and its potential pathological impact (e.g. post-traumatic stress disorder and depression), exposure to aversive stimuli is a relevant model for studying CNS plasticity. We present evidence that a single exposure to two predominantly emotional stressors [restraint in tubes and immobilization on wooden boards (IMO)] can modify the response of the hypothalamo-pituitary-adrenal (HPA) axis to a subsequent exposure to the same stressor days later in that a more rapid return to the baseline was observed in the poststress period. In addition, the effect was greater with IMO, the more severe stressor. Using IMO, we have further demonstrated that the effect of a previous single exposure to the stressor (i) increased with days elapsed between the two exposures; (ii) was specific for the previously experienced stressor; and (iii) was mediated via central-mediated effects [corticotropin-releasing factor (CRF) mRNA in the paraventricular nucleus of the hypothalamus]. These data suggest that animals retain memory about a single experience with stressors, resulting in an acceleration of the poststress recovery of the HPA axis that enhances progressively over a period of weeks. The extent to which the present data are relevant regarding post-traumatic stress disorders is unclear, but the study of the HPA response to severe stressors may be suitable for the study of the neurobiological basis of the progressive consolidation of learning over a long period of time (days to weeks).
Animals↗
In vitro antibacterial activity of Chilean red wines against Helicobacter pylori.
The antibacterial activity of sixteen Chilean red wines (Cabernet Sauvignon, Cabernet Merlot, Cabernet Organic and Pinot Noir), and the active extracts of two randomly selected wines were assayed for their antibacterial activity on six strains of Helicobacter pylori isolated from gastric biopsies. The active fraction of the wines was obtained by dichloromethane extraction, and the antibacterial activity of the wines and extracts was evaluated by an agar diffusion method. All the red wines studied showed some antibacterial activity on the six strains of H. pylori, although the strains were heterogeneous in their susceptibility to each particular wine. The active fraction of the two wines selected also showed good activity against the strains tested. The main active compound was identified as resveratrol. The results presented indicate that Chilean red wines have antibacterial activity against H. pylori, which depends mainly on the presence of resveratrol.
Anti-Bacterial Agents↗
[Minimally deviated adenocarcinoma (malignant adenoma) of the cervix uteri].
Minimal deviation adenocarcinoma (adenoma malignum) is a rare well-differentiated form of invasive cervical adenocarcinoma. Because of its rarity and cytologic changes are subtle there are only a few reports of this pathology, been necessary the realization of large biopsy of the cervical tissue for it histological diagnosis. We made a review in the period 1994-2000, of the clinical, cytological, histological features, treatments and follow-up of 4 patients in the Gynecologic Oncology Department of the University Hospital Vall d' Hebron, Barcelona, Spain.
Adenocarcinoma↗
[Serological certification of the interruption of the vectorial transmission of Chagas disease in Chile].
BACKGROUND: In 1999 an International Commission of Experts evaluated the sanitary interventions that started in 1980 to eliminate Triatoma infestans, the biological vector of Chagas disease, to certify if the conditions needed to interrupt the transmission, were achieved. AIM: To report the data used by the International certification commission to certify the interruption of vectorial transmission of Chagas disease in Chile. MATERIAL AND METHODS: A comparative evaluation of the prevalence of Trypanosoma cruzi antibodies in children surveyed between 1994 and 1995 and between 1995 and 1999. RESULTS: In the first period, 5,948 children were surveyed and in the second, 5,069 children were studied. Twenty children (0.4%) were positive for Trypanosoma cruzi antibodies in the second survey. These figures were significantly lower than the 1.1% prevalence detected between 1994 and 1995. In only three of the 20 cases, the transmission through vectors was confirmed, which represents a 99.4% reduction of this way of transmission. CONCLUSIONS: Based on these findings, the Commission certified that Chile is the second country in Latin America to interrupt the vector transmission of Chagas disease. The successful public health program for Chagas disease will have a positive impact improving the quality of life of rural populations, that are most exposed to the disease.
Animals↗
[Trypanosoma cruzi transplacental infection: situation in Chile].
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Chagas Disease↗
[In vitro antimicrobial susceptibility of Helicobacter pylori strains: isolation of strains resistant to clarithromycin].
BACKGROUND: Our laboratory has carried out an epidemiological surveillance of Helicobacter pylori antimicrobial susceptibility since 1997. AIM: To report the antimicrobial susceptibility of H pylori strains, isolated in Chile from August 1997 to August 2000. MATERIAL AND METHODS: Ninety one H pylori strains, obtained from antral gastric biopsies during upper gastrointestinal endoscopies were studied. Susceptibility towards clarithromycin, amoxicillin, bismuth subcitrate and metronidazole was studied by an agar diffusion technique. RESULTS: All strains were susceptible to amoxicillin and two strains were resistant to clarithromycin. Forty two percent of strains were resistant to metronidazole and 13% were resistant to bismuth subcitrate. CONCLUSIONS: These results underscore the need to maintain an epidemiological surveillance of H pylori antimicrobial susceptibility, to modify its eradication therapy accordingly.
Amoxicillin↗
[Helicobacter pylori: cagA analysis and vacA genotyping in Chile. Detection of a s2/m1 strain].
BACKGROUND: The genes cagA and vacA encode H pylori virulence factors. AIM: To genotype these genes in H pylori strains isolated from patients with upper gastrointestinal symptoms. MATERIAL AND METHODS: We studied 50 patients who underwent an upper gastrointestinal endoscopy, with positive culture for H pylori. Detection of cagA and vacA genotyping was done using polymerase chain reactions. RESULTS: The gene cagA was detected in 19 samples (38%). Signal sequences s1 and s2 of vacA gene were detected in 16 samples each (32%). There was simultaneous amplification of s1 and s2 in 6 samples and they were not detected in 9 samples. The middle region of vacA was m1 in 9 samples, m2 in 29 samples and there was simultaneous amplification of m1 and m2 in 12 samples. In 16 samples (32%), more than one type of signal sequence or medial region was detected. Of those patients in whom vacA was the only genotype detected, 15 were s2/m2, 7 were s1/m1, 4 were s1/m2 and 1 was s2/m1. CONCLUSIONS: In these patients, the infection with cagA- H pylori strains, predominates, the prevalence of infection with s1 or s2 strains is similar and the predominant medial region is m2.
Antigens, Bacterial↗
Gastric dilatation syndrome associated with chronic nephropathy, hypergastrinemia, and gastritis in mice exposed to high levels of environmental antigens.
Gastric dilatation (GD) has been observed in Tac:(SW)fBR surveillance mice, with mean age of 10 months, that are exposed to high levels of environmental antigens during routine exposure to dirty bedding. The aim of the study reported here was to determine whether GD was associated with other systemic conditions affecting mice. Three groups of nine animals including-surveillance mice not exposed to dirty bedding (control), surveillance mice with out GD (NGD), and surveillance mice with GD (group GD)-had mean stomach weight with ingesta of 0.5 +/- 0.02 g, 1.09 +/- 0.07 g (P < 0.0001), and 2.54 +/- 0.4 g (P < 0.0001), respectively. Mean serum creatinine concentration was significantly higher in GD (1.6 +/- 0.25 mg/dl), compared with NGD (0.17 +/- 0.22 mg/dl, P < 0.0001) and control (0.2 +/- 0.16 mg/ dl, P < 0.0001) mice. In addition, lesions consistent with severe chronic nephropathy and mild gastritis were common in GD, compared with NGD and control mice. Finally, serum amidated gastrin concentration was significantly high in GD (179.37 +/- 53.86 pM, P < 0.03) and NGD (264.89 +/- 115.89 pM, P < 0.009), compared with control (60.77 +/- 8.39 pM) mice. Gastric dilatation syndrome is associated with chronic nephropathy, hypergastrinemia, and gastritis in surveillance mice exposed to high levels of environmental antigens.
Animals↗
Surfactant protein genetic marker alleles identify a subgroup of tuberculosis in a Mexican population.
Pulmonary surfactant and its components are essential for normal lung function and are involved in local host defense. Surfactant protein (SP)-A and SP-D bind to and modulate phagocytosis of Mycobacterium tuberculosis by macrophages. Frequency comparisons of SP marker alleles in tuberculosis patients and healthy control subjects (tuberculin-skin test positive or general population) were performed. Regression analyses of the tuberculosis and the tuberculin-skin test positive groups revealed, on the basis of odds ratios, tuberculosis susceptibility (DA11_C and GATA_3) and protective (AAGG_2) marker alleles. Similarly, between tuberculosis patients and general population control subjects, susceptibility 1A(3), 6A(4), and B1013_A and protective AAGG_1, and AAGG_7 marker alleles were observed. Moreover, interactions were seen between alleles 6A(2) and 1A(3) (P=.0064) and between 1A(3) and B1013_A (P=. 036). The findings indicate a possible involvement of SP alleles in tuberculosis pathogenesis.
Adult↗
Shape of the 8B alpha and neutrino spectra.
The beta-delayed alpha spectrum from the decay of 8B has been measured with a setup that minimized systematic uncertainties that affected previous measurements. Consequently the deduced neutrino spectrum presents much smaller uncertainties than the previous recommendation [J. N. Bahcall et al., Phys. Rev. C 54, 411 (1996)]. The 8B nu spectrum is found to be harder than previously recommended with about (10-20)% more neutrinos at energies between 12-14 MeV. The integrated cross sections of the 37Cl, 71Ga, 40Ar, and Super-Kamiokande detectors are, respectively, 3.6%, 1.4%, 5.7%, and 2.1% larger than previously thought.
Journal Article↗
Perineurium contributes to axonal damage in acute inflammatory demyelinating polyneuropathy.
OBJECTIVE: To assess if axonal damage in severe acute inflammatory demyelinating polyneuropathy (AIDP) correlates with the appearance of epiperineurium in nerve trunks. BACKGROUND: Increase of endoneurial fluid pressure in nerve trunks possessing epiperineurium may be an important mechanism of axonal damage in AIDP. METHODS: A 79-year-old man had a 2-day history of acroparesthesias and ascending paralysis culminating in quadriplegia, bilateral facial palsy, and mechanical ventilation. Five intravenous immunoglobulin cycles were given without response. He died on day 60. Electrophysiologic studies (days 4, 17, and 50) initially showed normal nerve conduction velocities with further slowing, progressive attenuation of compound muscle action potentials, and profuse denervation. The authors studied the preforaminal anterior and posterior L3 and L5 spinal roots, third and fifth lumbar nerves and their branches, and femoral and sural nerves. RESULTS: Density of myelinated fibers was preserved in L5 ventral and dorsal roots and reduced in sural nerve. Mild de-remyelination was observed in lumbar roots. In both lumbar nerves and their branches, there were extensive de-remyelination and centrofascicular or wedge-shaped areas with marked loss of large myelinated fibers. Axonal degeneration was the predominant lesion in sural nerve. CONCLUSION: The presence of epiperineurium correlates with a drastic change of pathology with superimposed ischemic lesions and distally accentuated axonal loss, suggesting that endoneurial fluid pressure increase could cause axonal damage in AIDP.
Action Potentials↗
Development and validation of a capillary electrophoresis method for direct measurement of isocitric, citric, tartaric and malic acids as adulteration markers in orange juice.
Fruit juices each have very distinct organic acids profiles that can be used as fingerprints for establishing authenticity. A method has been developed, optimised and validated for measuring by capillary electrophoresis citric, isocitric, malic and tartaric acids as authenticity markers in orange juices, without any sample treatment other than dilution and filtration. Final conditions were phosphate buffer 200 mM, pH 7.50, -14 kV as applied potential, and 57 cm length neutral capillary. Detection was direct UV at 200 nm. Different kinds and marks of orange juice, chosen from the great variety existent in the market, were analysed and clear differences could be found between them and just pressed orange juice.
Beverages↗