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E Castañeda

Publications and source records attributed to E Castañeda.

At least 37 records · Page 2Linked to original sources
PubMed1998

Invasive Streptococcus pneumoniae infection in Latin American children: results of the Pan American Health Organization Surveillance Study.

Protein-polysaccharide conjugate vaccines against Streptococcus pneumoniae promise to be an effective public health intervention for children, especially in an era of increasing antimicrobial resistance. To characterize the distribution of capsular types in Latin America, surveillance for invasive pneumococcal infection in children < or = 5 years of age was done in six countries between February 1993 and April 1996. Fifty percent of 1,649 sterile-site isolates were from children with pneumonia, and 52% were isolated from blood. The 15 most common of the capsular types prevalent throughout the region accounted for 87.7% of all isolates. Overall, 24.9% of isolates had diminished susceptibility to penicillin: 16.7% had intermediate resistance and 8.3% had high-level resistance. Three customized vaccine formulas containing 7, 12, and 15 capsular types were found to have regional coverages of 72%, 85%, and 88%, respectively. This study emphasizes the need for local surveillance for invasive pneumococcal disease prior to the development and evaluation of protein-polysaccharide conjugate vaccines for children.

Bacterial Vaccines↗
PubMed1998

Molecular epidemiologic characterization of penicillin-resistant Streptococcus pneumoniae invasive pediatric isolates recovered in six Latin-American countries: an overview. PAHO/Rockefeller University Workshop. Pan American Health Organization.

The Pan American Health Organization (PAHO) has conducted a study of Streptococcus pneumoniae in six Latin-American countries: Argentina, Brazil, Chile, Colombia, Mexico, and Uruguay. Sterile site isolates from children aged < or =5 years showing clinical symptoms of pneumonia (as defined by the clinical criteria of WHO), meningitis, sepsis or bacteremia (without infectious foci), arthritis, and peritonitis were the source of most of the invasive pneumococcal isolates collected between the end of 1993 and 1996 in the six participating countries. Partial characterization of these isolates (antibiotic resistance and serotyping) have already been described (Microbial Drug Resistance 3:(2):131-163, 1997). In the next phase of the study, 326 S. pneumoniae isolates with reduced penicillin susceptibility were transferred to the Laboratory of Microbiology at The Rockefeller University for molecular characterization, and a summary and overview of the findings is described in this article. Some of the most interesting findings were as follows: (1) There was a surprisingly high representation of two internationally spread clones, which made up >80% of the strains with penicillin MIC of 1 microg/ml or higher; most of these isolates were recovered in large cities, supporting the likelihood that the source of these clones is through international travel. (2) The frequency of resistance to trimethoprim/sulfamethoxazole was extremely high (present in 85% of all isolates with decreased penicillin susceptibility). (3) None of these isolates was resistant to ofloxacin, and macrolide resistance was rare (present in 6.4% of the isolates). (4) There was an apparent inverse relationship between level of penicillin resistance and genetic diversity. (5) There were striking differences in the "microbiologic profiles" of the six different Latin-American countries.

Child↗
PubMed1998

Penicillin-resistant Streptococcus pneumoniae in Colombia: presence of international epidemic clones. Colombian pneumococcal study group.

The global spread of multidrug-resistant Streptococcus pneumoniae clones is well documented in the literature. A study to determine type distribution and antimicrobial susceptibility of invasive pneumococcal isolates from Colombian children under the age of 5 was conducted from 1994 to 1996. Health centers in Santa Fe de Bogota, Medellin, Cali, and other cities collected 409 Streptococcus pneumoniae isolates. Diminished susceptibility to penicillin (DSP) was 15.6%; from these, 11.5% showed intermediate-level resistance (ILR) and 4.1% showed high-level resistance (HLR). Fifty-nine of the DSP isolates were examined by pulse field gel electrophoresis (PFGE). Capsular isolate types were 23F (54%), 14 (24%), 19F (10%), 6B (7%), 9V (3%), and 34 (2%). PFGE analysis revealed that 8 isolates shared the Spanish/USA international clone's characteristic features: PFGE pattern type A, serotype 23F; 87.5% exhibited HLR for penicillin, and all were resistant to trimethoprim/sulfamethoxazole (TMP-SMX), tetracycline, and chloramphenicol. Another 7 isolates showed the French/Spanish international clone's features: PFGE pattern type B, 2 of them being serotype 9V; and 5 type 14; HLR to penicillin was 71%, and all proved resistant to TMP-SMX. A large cluster of 24 isolates (41% of all isolates examined) shared a common PFGE type C, with 14 subtypes; all but one, serotype 34, were serotype 23F and had ILR to penicillin; 58% were resistant to TMP-SMX and 50% to tetracycline, but none presented erythromycin or chloramphenicol resistance. The remaining 20 isolates could be grouped into 12 different PFGE types; ILR was shown in 75% of isolates, 70% were resistant to TMP-SMX and to tetracycline, 15% were resistant to erythromycin, and none were resistant to chloramphenicol. These data suggest that some Colombian isolates are clonally related to two of the well-known international epidemic S. pneumoniae clones.

Colombia↗
PubMed1998

First isolation of Cryptococcus neoformans var. gattii, serotype C, from the environment in Colombia.

The natural habitat of Cryptococcus neoformans var. gattii, serotype B in the environment was established by Australian investigators who demonstrated its association with species of Eucalyptus. The aim of the present study was to search for the habitat of this variety in a city of Colombia, where clinical cases due to this variety occur with great frequency. For a period of 5 months detritus, vegetable material and air samples in and around 68 almond trees (Terminalia catappa) located in the city were studied. C. neoformans var. gattii serotype C was the only variety isolated from two of the 68 trees sampled. These trees were positive for 4 of the 5 months during which they were studied. From the first positive sample kept under refrigeration, it was possible to isolate the fungus up to 3 months later. This is the first report of the isolation of serotype C from the environment. More studies are required in order to establish the ecological significance of this finding.

Air Microbiology↗
PubMed1997

Distribution of capsular types and antimicrobial susceptibility of invasive isolates of Streptococcus pneumoniae in Colombian children. Pneumococcal Study Group in Colombia.

Streptococcus pneumoniae is the leading bacterial cause of childhood pneumonia in the developing world. This study describes the type distribution and antimicrobial susceptibility of invasive pneumococcal isolates from Colombian children and is part of the Sistema Regional de Vacunas (SIREVA), a PAHO regional initiative designed to determine the ideal serotype composition of a protein polysaccharide pneumococcal conjugate vaccine for use in children less than 5 years old in Latin America. In Colombia, during the study period, centres in Bogota, Medellin, and Cali collected 324 S. pneumoniae isolates from invasive diseases, 238 (73.5%) from children under the age of 2. Pneumonia was the clinical diagnosis in 41.3% cases, meningitis in 41%, and sepsis in 11.2%. The seven most frequent types included 14(21.9%), 5(10.5%), 23F(9.6%), 1(9%), 6B(9%), 19F(7.1%), and 6A(6.2%). The frequency of diminished susceptibility to penicillin (DSP) was 12%, with 8.9% of isolates showing intermediate level resistance and 3.1% showing high level resistance. Among DSP isolates, 23% were also resistant to cefotaxime, 33.3% to erythromycin, 48.7% to chloramphenicol, and 74.3% to trimethoprim/sulfamethoxazole. Multiple resistance was detected in 59% of the isolates that have DSP. Penicillin resistance was associated with types 23F (53.8%) and 14 (25.6%). These data provides information on capsular types prevalent in Colombia that will not only allow the formulation of an ideal vaccine for the region but also reinforce the need for ongoing regional surveillance.

Anti-Bacterial Agents↗
PubMed1997

Molecular epidemiology of Vibrio cholerae O1 isolates from Colombia.

A total of 173 Vibrio cholerae O1 isolates from the recent cholera epidemic in Colombia was analysed by the polymerase chain reaction (PCR) for the genes encoding the A subunit of cholera toxin (ctxA) and the zonula occludens toxin (zot), and by ribotyping. All isolates were positive for ctx A and zot, which was confirmed by hybridisation. Ribotyping with restriction endonuclease Bg/I digestion of total DNA revealed three ribotypes: B5a comprising 165 (96.4%) isolates, and two new designated ribotypes B20 and B21a in six (3.5%) isolates and two (1.1%) isolates, respectively. These findings have significant public health implications.

Bacterial Typing Techniques↗
PubMed1997

[Madurella mycetomatis antigen for the serodiagnosis of mycetoma].

The aim of this work was to standardize metabolic and cytoplasmic Madurella mycetomatis antigen to be applied in the immunodiagnosis of mycetoma. Growth curves were established growing the mold in two broth media with weekly measures of protein and carbohydrate levels and of dry weight. Sera from immunized rabbits and patient's sera were used in immunoprecipitation to test the antigens. Three weeks old shaken cultures in Sabouraud broth at 37 degrees C were established as the optimal conditions to prepare cytoplasmic and metabolic antigens. Nevertheless, exoantigens were produced since the first week. Metabolic and cytoplasmic antigens presented cross reaction and by immunoblotting they shared 33, 56 and 125 kDa molecular weight proteins. Preparation and use of the metabolic antigens is recommended for the immunodiagnosis of mycetoma when using the counterimmunoelectrophoresis technique.

English Abstract↗
PubMed1997

[The value of immunological assays in the diagnosis of meningeal histoplasmosis].

INTRODUCTION: Between 1985 and 1995, 3,860 cerebrospinal fluid (CSF) samples from patients with mycotic meningitis were analyzed. METHODS: Direct examination, cultures, complement fixation (CF) and immunodiffusion (ID) with Histoplasma capsulatum were carried out. RESULTS: Seventy four samples from 31 patients (three of them with AIDS) were reactive at the immunological assays. Cultures were positive in five patients. In 26 patients the clinical diagnosis together with positive CSF assays gave indirect evidence of meningeal histoplasmosis. ID and CF reactivity were 93.5% and 100% respectively. For 23 patients who had simultaneous examination of blood and CSF the double positivity was 78.2%. CONCLUSIONS: Because of the direct isolation of Histoplasma capsulatum is a difficult one, the diagnosis of subacute or chronic meningeal histoplasmosis may be confirmed by indirect immunological assays.

Adolescent↗
PubMed1996

Effects of amphetamine and 6-hydroxydopamine lesions on reserpine-induced oral dyskinesia.

The present study examined whether reserpine-induced oral dyskinesia is mediated by release of residual endogenous dopamine. Amphetamine produced a dose-dependent change in reserpine-induced oral dyskinesia in which the response was exacerbated by 0.6 mg/kg amphetamine and inhibited by 1 mg/kg. The latter dose also produced stereotypy that may have interfered with expression of reserpine-induced oral dyskinesia. Nigrostriatal 6-hydroxydopamine lesions attenuated expression of reserpine-induced oral dyskinesia. These lesions did not reduce locomotor activity, however, indicating that the attenuation of reserpine-induced oral dyskinesia was not due to a general depressant effect of the lesions on motor behavior. These results suggest that increasing dopamine release by administration of amphetamine exacerbates reserpine-induced oral dyskinesia, whereas decreasing the amount of releasable dopamine in the striatum by 6-hydroxydopamine lesions attenuates reserpine-induced oral dyskinsia. These findings may have implications for understanding tardive dyskinesia and L-3,4-dihydroxyphenylalanine (L-DOPA)-induced dyskinesia.

Adrenergic Agents↗
PubMed1996

Changes in behavior and monoamine levels in microdialysate from dorsal striatum after 6-OHDA infusions into ventral striatum.

Long-Evans rats received bilateral 6-hydroxydopamine infusions into the nucleus accumbens and were tested immediately (1 and 2 days) or after a recovery period (14 and 15 days) for changes in extracellular levels of dorsal striatal monoamines using in vivo microdialysis. Compared to controls, the monoamine metabolites 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindoleacetic acid were generally enhanced when tested immediately after 6-hydroxydopamine treatment, including spontaneous levels and those following depolarizing infusions of potassium (60 mM, 20 min) through the microdialysis probes. Following 2 weeks recovery, dopamine metabolite levels were depressed and the serotonin metabolite levels remained enhanced. D-Amphetamine sulfate (1.5 mg/kg, SC) stimulated dopamine overflow was enhanced 2 days after 6-hydroxydopamine administration, but not after 2 weeks recovery. In contrast, potassium increased dopamine overflow to the same extent as control animals regardless of recovery period following 6-hydroxydopamine. The immediate changes in striatal monoamine activity were accompanied by a potentiation of amphetamine-induced stereotyped behaviors. We suggest that transient presynaptic changes within the dorsal striatum following disruption of the ventral striatum may mediate some general aspects of loss and recovery of behavior related to the time course of 6-hydroxydopamine neurotoxicity.

Adrenergic Uptake Inhibitors↗
PubMed1996

Dopamine overflow in the nucleus accumbens during extinction and reinstatement of cocaine self-administration behavior.

Both cocaine and cocaine-associated stimuli can reinstate extinguished self-administration behavior in animals. It has been suggested that reinstatement of drug-seeking behavior may be mediated by enhanced dopamine (DA) neurotransmission. To examine this hypothesis, DA overflow was measured in the nucleus accumbens (NAc) of rats during both extinction and cocaine-induced reinstatement of self-administration behavior. Rats were either allowed to self-administer cocaine for 3 hours daily for 14 days, or they received yoked administration of saline. A stimulus light above the lever was illuminated during drug delivery. Baseline DA overflow was measured in the NAc, using in vivo microdialysis 7 to 8 days after the last self-administration session. The rats were then placed into the operant chambers and allowed to respond in extinction for 90 minutes, during which responses resulted in presentation of the stimulus light. The rats then received a cocaine injection that reinstated self-administration behavior. Contrary to our hypothesis, cocaine-experienced animals exhibited less DA overflow in the NAc relative to controls during both extinction and reinstatement.

Animals↗
PubMed1995

Safety and immunogenicity of oral killed whole cell recombinant B subunit cholera vaccine in Barranquilla, Colombia.

In January and February 1992, an assessment was conducted of the safety and immunogenicity of two doses of a new oral cholera vaccine prepared from the recombinant B subunit of the toxin and from killed whole cells (rBS/WC) in 1,165 individuals between the ages of 12 months and 64 years in Barranquilla, Colombia. This was a randomized, double-blind placebo-controlled study. Participants received two doses of either the vaccine or a placebo (killed Escherichia coli K12) over a two-week interval. Few symptoms were detected during the three days following administration of the initial dose and even fewer following the second. Sera obtained upon administration of the first dose and two weeks after administration of the second were tested for Vibrio cholerae 01 Inaba vibriocidal antibodies and antitoxins. Geometric mean titers (GMT) of vibriocidal antibodies were found to increase two-fold in subjects receiving the vaccine. In the paired samples taken from vaccinated subjects, two-fold or greater increases were observed in 44% and four-fold or greater increases were observed in 34%, as compared to similar increases in 9.2% and 2.2% of the sera taken from those receiving the placebo (P < 0.05). The GMTs of IgG and IgA antitoxins, as determined by ELISA, increased by factors of 4 and 3.2, respectively, in those receiving the vaccine, as compared to factors of 1.1 and 1.1 in those given the placebo (P < 0.001 for IgG, P < 0.01 for IgA). Approximately 80% of the paired samples from the vaccinated group showed an increase of both IgG and IgA antitoxins > or = 1.5, as compared to only about 20% of those in the placebo group (P < 0.000001). Belonging to the O blood group did not significantly affect the immune response. Children under age four tended to show a weaker vibriocidal antibody response and a stronger antitoxin response than older subjects. The two doses of oral vaccine were found to be safe and without attributable side-effects. The vibriocidal antibody and antitoxin responses were similar to those obtained previously with the conventional oral killed whole cell B subunit cholera vaccine.

Administration, Oral↗
PubMed1994

Making two movements at once: impairments of movement, posture, and their integration underlie the adult skilled reaching deficit of neonatally dopamine-depleted rats.

Adult rats depleted bilaterally of dopamine in infancy display a profound impairment in skilled forelimb use in reaching for food. This impairment was investigated using end-point measures of reaching success, movement analysis, and kinematic measures. The rats made few successful reaches in either an easy or a difficult reaching test. Their reaches were characterized by many attempts in which trajectories of the limb were irregular and the movements were slow. Their lack of success was related in part to an impairment in making component movements of the reach, including aiming, pronating, grasping, and supinating the paw and in releasing the food pellet. It was also related to an inability to adjust posture as the limb was voluntarily moved toward the food. The results are consistent with the hypotheses that the basal ganglia, including its dopamine innervation, is important for enabling voluntary movements and postural adjustments and perhaps also the simultaneous performance of two movements at the same time.

Aging↗
PubMed1994

Dose-dependent differences in the development of reserpine-induced oral dyskinesia in rats: support for a model of tardive dyskinesia.

Rats treated with reserpine develop spontaneous orofacial dyskinesia that has features similar to tardive dyskinesia (TD) in humans. In contrast to TD, however, reserpine-induced oral dyskinesia develops rapidly reaching a maximal level within 3 days at a dose of 1 mg/kg per day. The present study examined whether rats administered lower doses of reserpine would develop the oral dyskinesia at a slower rate, similar to the protracted development of TD. Rats were administered 0, 0.01, 0.05, 0.1, or 1.0 mg/kg reserpine subcutaneously every other day for 100 days. Oral dyskinesia was measured by recording the incidence of tongue protrusions for 30 min on days 1, 4, 10, 20, 40, 60, and 100. The time course of the development of reserpine-induced oral dyskinesia varied dose-dependently. The response was evident within 4 days at 1 mg/kg, within 20 days at 0.1 mg/kg, within 60 days at 0.05 mg/kg, and was not evident at 0.01 mg/kg at any time during the 100 days of treatment. The protracted development of reserpine-induced oral dyskinesia at the lower doses is consistent with TD. Doses of reserpine that produced an increase in tongue protrusions also produced a 90-95% depletion of dopamine and an increase in the ratio of dopamine metabolites to dopamine in the caudate-putamen. The disruption of dopamine neurotransmission may be involved in development of the oral dyskinesia. Furthermore, it is suggested that the 1 mg/kg dose of reserpine may induce neurochemical changes similar to that produced by long-term neuroleptic treatment, but at an accelerated rate, thereby providing a new efficient model of TD.

Animals↗
PubMed1994

Kinetics of the vibriocidal antibody response to live oral cholera vaccines.

The best correlate of protection against cholera is the level of serum vibriocidal antibodies, which are primarily directed against the O antigen of Vibrio cholerae O1 and lyse V. cholerae in the presence of complement. We established the timing of peak vibriocidal antibody response using sera from safety/immunogenicity studies of live oral cholera vaccines CVD 103-HgR, CVD 103-HgR2 and CVD 110 among immunologically naive North Americans and Colombians. The serum reciprocal vibriocidal antibody titre was consistently higher 10 days postimmunization than on either day 7 or day 14. This study suggests that recent phase 2 studies of CVD 103-HgR may have underestimated the peak vibriocidal titre by collecting serum on days 7-8 rather than on day 10; future studies of live oral cholera vaccines should take these results into account to obtain the best measurement of peak immunological responses. Because of the rapid drop in vibriocidal antibody titres about 2 weeks after immunization, care must be exercised in comparing immunogenicity of different vaccine candidates, formulations, dosage levels and immunization schedules.

Administration, Oral↗
PubMed1994

Skilled reaching deficits in unilateral dopamine-depleted rats: impairments in movement and posture and compensatory adjustments.

Rats receiving unilateral dopamine (DA) depletions have bilateral deficits in using the forelimbs for skilled reaching. These impairments were investigated using end-point, video, and kinematic measures. Control rats and groups of rats with > 98% unilateral depletions (confirmed by tissue, apomorphine, and amphetamine assay), produced by 6-hydroxydopamine (6-OHDA) injected into the nigrostriatal bundle, were tested for 100 d on two reaching tasks. One depleted group used the contralateral-to-lesion (bad), and the other the ipsilateral-to-lesion (good), limb. Rats using their bad limb made few successful reaches and had dysfunctions in aiming, pronating, and supinating, and in using the digits to grasp and release food. Rats using the good limb were initially impaired, but improved, and could make these movements. Neither depleted group was able to use their bad limbs to assist actively the postural changes required for reaching. Thus, they did not use the diagonal supporting pattern (the nonreaching forelimb and diagonal hind limb) from which control rats initiated reaching. The group using their bad limb initiated reaching from a base of support distributed on the ipsilateral-to-lesion limbs, while the group using their good limb initiated reaching from a base of support centered on the ipsilateral rear limb. The impairments in making voluntary movements and postural adjustments with the bad limbs and the behavioral changes introduced by the compensatory dependency on good limbs account for the bilateral deficits in skilled movements. The results show that DA is required for skilled movements and postural adjustments and demonstrate that behavioral compensation can contribute to recovery.

Adaptation, Physiological↗
PubMed1993

The role of the striatum in organizing sequences of play fighting in neonatally dopamine-depleted rats.

Juvenile rats sustaining dopamine depletions by intraventricular injections of 6-hydroxydopamine (6-OHDA) as neonates were used to study the role of the striatum in controlling play fighting. As juveniles, the rats exhibited all the behavior elements typical of play fighting. However, they were more likely to use defensive tactics that shortened the playful contact between partners; and when contacting the partner, they were more likely to switch to other behaviors, such as allogrooming and sexual mounting, rather than continue with the play sequence. It is suggested here that the striatum is important for maintaining sequential organization of play fighting.

Aggression↗