Biomedical subjects

Juan J García

Publications and source records attributed to Juan J García.

13 recordsLinked to original sources

PubMed2006

Entomophthora ferdinandii (Zygomycetes: Entomophthorales) causing natural infections of Musca domestica (Diptera: Muscidae) in Argentina.

The identity and activity of an entomopathogenic fungus belonging to the Entomophthora muscae species complex and infecting Musca domestica in poultry houses from La Plata, Argentina, is reported. Entomophthora caused natural infections between September 2001 and September 2003. Primary conidia of this fungus were on average 29.5 +/- 1.2 x 23.4 +/- 2.4 microm and contained, on average, 10.5 +/- 0.1 nuclei (range: 7-15) with an average diameter of 4.8 +/- 0.1 microm. This fungus is identified as E. ferdinandii Keller (this specific epithet includes a nomenclaturally required spelling correction); this is a first record of E. ferdinandii in South America and of any member of the E. muscae species complex from flies in Argentina.

Animals↗

PubMed2006

Isolation of Paecilomyces lilacinus (Thom) Samson (Ascomycota: Hypocreales) from the Chagas disease vector, Triatoma infestans Klug (Hemiptera: Reduviidae) in an endemic area in Argentina.

A survey for entomopathogenic fungi of the Chagas disease vector Triatoma infestans was conducted in two provinces of Argentina from March-December 2003. Field-collected insects that died in the laboratory were individually maintained in moist chamber and incubated at 22 degrees C. Triatominae adults infected with the fungus Paecilomyces lilacinus were found at El Quebracho (27 degrees 34'S-64 degrees 31'W), Santiago del Estero province, Argentina, in December 2003. Paecilomyces lilacinus was cultured and isolated from infected insects in SDAY, PYG and MEA media. Pathogenicity tests were conducted and positive results were recorded. The median survival time (MST) of T. infestans exposed to a P. lilacinus conidial suspension was 12.8 days, and 100% mortality occurred at 30 days post-treatment. This is the first record of natural infection caused by P. lilacinus in T. infestans in the world.

Animals↗

PubMed2006

Pretransplantation consolidation chemotherapy decreases leukemia relapse after autologous blood and bone marrow transplants for acute myelogenous leukemia in first remission.

Controversy exists over whether pretransplantation consolidation chemotherapy affects the outcome of subsequent autotransplantation for acute myelogenous leukemia (AML). The current study was undertaken to determine the association between previous consolidation and outcome of autotransplantation for AML in first remission. Posttransplantation outcomes of 146 patients receiving no consolidation were compared with those of 244 patients receiving standard-dose (<1 gm/m(2)) and 249 patients receiving high-dose (1-3 gm/m(2)) cytarabine, using proportional hazards regression to adjust for differences in prognostic variables. One-year transplantation-related mortality was similar among the cohorts. Five-year relapse rates were 49% (95% confidence interval CI} = 39%-58%) with no consolidation, 35% (95% CI = 29%-42%) with standard-dose cytarabine, and 40% (95% CI = 33%-48%) with high-dose cytarabine (P = .07). Five-year leukemia-free survival rates were 39% (95% CI = 30%-47%) with no consolidation, 53% (95% CI = 46%-60%) with standard-dose cytarabine, and 48% (95% CI = 40%-56%) with high-dose cytarabine (P = .03). Similarly, 5-year overall survival was better in those patients receiving consolidation: 42% (95% CI = 34%-51%) with no consolidation, 59% (95% CI = 52%-65%) with standard-dose cytarabine, and 54% (95% CI = 46%-61%) with high-dose cytarabine (P = .01). Although most patients received 1 or 2 cycles of consolidation, the number of courses had no detectable effect on transplantation outcome. In multivariate analysis, risks of relapse and treatment failure were lower in the patients receiving consolidation, especially among those patients receiving blood cell grafts. Outcomes with standard-dose and high-dose cytarabine were similar. Based on our findings, we recommend that patients with AML in first remission receive consolidation before undergoing autotransplantation.

Adolescent↗

PubMed2006

Auditing secondary prevention of ischaemic heart disease in rural areas of Spain: an opportunity for improvement.

AIM: To describe the standard of secondary prevention received by individuals with a history of ischaemic heart disease (IHD) in Spanish rural areas, and the factors associated with low standards of quality. METHODS: Medical audit of patients with a history of IHD, whose data were provided by 72 rural physicians in 12 autonomous regions (1030 cases). Quality criteria were used based on international guidelines. Multivariate analysis was employed to assess the variables associated with poor-quality attention. RESULTS: 30.9% of patients gave target low-density lipoprotein (LDL) readings, and 68.1% reached target blood pressure (BP). Beta-blockers were taken by 48.5%. Twenty-nine per cent of patients had not visited a specialist within the previous year. The fact that patients had visited a specialist within the previous year was associated with their having followed the types of treatments recommended in the guidelines (p < 0.01) and with obtaining target LDL and BP readings (p < 0.05). Patients from the smallest villages had the lowest probability of having LDL controls and also of receiving hypolipidaemic therapy (p<0.01). Those with a past history of isolated angina had lower probability of being treated with antiaggregants than those who had experienced previous acute myocardial infarction (p < 0.01). CONCLUSION: The quality of secondary prevention for these patients shows there is room for improvement. Problems of accessibility exist for some groups, which may be improved with the involvement of rural primary healthcare teams.

Adult↗

PubMed2006

Predation efficiency of indigenous larvivorous fish species on Culex pipiens L. larvae (Diptera: Culicidae) in drainage ditches in Argentina.

Two neotropical freshwater fish species, Cnesterodom decemmaculatus (Poeciliidae) and Jenynsia multidentata (Anablepidae), were collected from human-made ditches, a common habitat of the house mosquito Culex pipiens in La Plata, Argentina. Cnesterodom decemmaculatus was recorded in 62 of the 100 examined ditches, whereas J. multidentata was collected from only 21 ditches sympatrically with C. decemmaculatus. Culex pipiens was the only mosquito species collected, and its larvae and pupae were found in 38 of the 100 ditches. Fish and mosquito larvae and pupae were collected together in only two ditches and were significantly negatively correlated. Siphons of larval Culex and remnants of chironomid larvae, copepods, aquatic mites, and fish were present in the gut contents of two C. decemmaculatus from mosquito-positive ditches, while diatoms and filamentous algae were recorded in every fish dissected. Adult C. decemmaculatus and J. multidentata needed approximately 6.2 h to completely digest one Cx. pipiens 4th instar larva under laboratory conditions. When fish were confined with a density of 60 or fewer Cx. pipiens 4th instar larvae, C. decemmaculatus and J. multidentata adults consumed 100% of them in one day but only 35% and 42%, respectively, when confined with 150 larvae. Eradication of Cx. pipiens from a ditch, where densities had averaged 250 immatures per dip, was achieved 17 days after the introduction of 1,700 C. decemmaculatus.

Animals↗

PubMed2006

High reliability outdoor sonar prototype based on efficient signal coding.

Many mobile robots and autonomous vehicles designed for outdoor operation have incorporated ultrasonic sensors in their navigation systems, whose function is mainly to avoid possible collisions with very close obstacles. The use of these systems in more precise tasks requires signal encoding and the incorporation of pulse compression techniques that have already been used with success in the design of high-performance indoor sonars. However, the transmission of ultrasonic encoded signals outdoors entails a new challenge because of the effects of atmospheric turbulence. This phenomenon causes random fluctuations in the phase and amplitude of traveling acoustic waves, a fact that can make the encoded signal completely unrecognizable by its matched receiver. Atmospheric turbulence is investigated in this work, with the aim of determining the conditions under which it is possible to assure the reliable outdoor operation of an ultrasonic pulse compression system. As a result of this analysis, a novel sonar prototype based on complementary sequences coding is developed and experimentally tested. This encoding scheme provides the system with very useful additional features, namely, high robustness to noise, multi-mode operation capability (simultaneous emissions with minimum cross talk interference), and the possibility of applying an efficient detection algorithm that notably decreases the hardware resource requirements.

Data Compression↗

PubMed2004

Ultrasonic ranging sensor using simultaneous emissions from different transducers.

In recent applications based on ultrasound, several ultrasonic transducers have been geometrically and electronically associated to constitute a global sensor. There are several different methods used to process the ultrasonic signals obtained from these transducers. In this work, multimode techniques using Golay complementary sequences are proposed for processing the ultrasonic signal. The system increases scan rate, precision, and reliability. It is also capable of echo discrimination, allowing simultaneous measurements to be made and detection of the same obstacle by different transducers without cross-talk problems. The real-time implementation of the algorithm is presented on a field-programmable gate array (FPGA) device.

Algorithms↗

PubMed2003

Effect of first-pass hepatic metabolism on the disposition of levamisole after intravenous administration in rabbits.

OBJECTIVE: To evaluate the contribution of first-pass hepatic metabolism of levamisole on levamisole disposition in rabbits. ANIMALS: 30 male New Zealand White rabbits. PROCEDURES: Rabbits were randomly placed into 2 groups. Rabbits in the first group received levamisole via the marginal ear vein at the following 3 doses: 12.5, 16, and 20 mg/kg (5 rabbits for each dose). Rabbits of the second group received levamisole via the jejunal vein at the same doses (5 rabbits each). During the following 240-minute period, plasma samples were obtained and quantified for levamisole concentrations by reversed-phase high-performance liquid chromatography. RESULTS: No significant differences were found between pharmacokinetic parameters calculated by compartmental or noncompartmental analysis. Mean hepatic extraction ratio ranged from -0.044 to 0.017 and from 0.020 to 0.081 when area under the plasma concentration-time curve values were obtained after compartmental or noncompartmental analysis, respectively. After compartmental analysis, plasma concentration decreased bi-exponentially. Mean pharmacokinetic parameter values were as follows for each dose (12.5, 16, and 20 mg/kg, respectively): after levamisole administration via the marginal ear vein, volume of distribution at steady state (Vss) = 4.26, 4.33, and 3.20 L/kg; total body clearance (CI) = 49.04, 43.77, and 39.26 mL/kg x min; and half-life associated with beta-phase (t1/2beta) = 77.93, 85.39, and 69.79 minutes. After levamisole administration via the jejunal vein, Vss = 4.38, 2.85, and 2.97 L/kg; CI = 48.14, 42.40, and 39.69 mL/kg x min; and t1/2b = 101.9, 76.71, and 76.13 minutes. CONCLUSIONS: Levamisole has a low degree of hepatic extraction in rabbits.

Animals↗

PubMed2003

Life cycle and epizootiology of Amblyospora ferocis (Microspora: Amblyosporidae) in the mosquito Psorophora ferox (Diptera: Culicidae).

A natural population of Psorophora ferox (Humbold, 1820) infected with the microsporidium Amblyospora ferocis Garcia et Becnel, 1994 was sampled weekly during a seven-month survey in Punta Lara, Buenos Aires Province, Argentina. The sequence of development of A. ferocis in larvae of P. ferox leading to the formation of meiospores followed the developmental pathway previously reported for various species of Amblyospora. The natural prevalence of A. ferocis in the larval population of P. ferox ranged from 0.4% to 13.8%. Spores were detected in the ovaries of field-collected females of P. ferox and were shown to be responsible for transovarial transmission of A. ferocis to the next generation of mosquito larvae in laboratory tests. These spores were binucleate and slightly pyriform in shape. The prevalence of A. ferocis in the adult population ranged from 2.7% to 13.9%. Data on effects of the infection on female fecundity showed that infected field-collected adults of P. ferox laid an average of 47.6 +/- 6.5 eggs of which 35.8% +/- 4.1% hatched. Uninfected field-collected adults of P. ferox laid 82.8 +/- 6.8 eggs of which 64.1% +/- 5.5% hatched. Six species of copepods living together with P. ferox were fed meiospores from field-infected larvae but none became infected. Horizontal transmission of A. ferocis to P. ferox larvae remains unknown.

Animals↗

PubMed2002

Intra-arterial pharmacokinetics and pulmonary first-pass of levamisole in rabbits.

The pharmacokinetics of levamisole after intra-arterial administration of 12.5, 16 and 20 mg kg (-1) was investigated in rabbits. After compartmental analysis, the disposition of levamisole was well described by a two-compartment open model with mean values +/- sd of: alpha= 0.1650 +/- 0.0839, 0.1611 +/- 0.0298, 0.2312 +/- 0.0540 min (-1), and beta= 0.0118 +/- 0.0022, 0.0125 +/- 0.0026, 0.0120 +/- 0.0024 min (-1), for the three doses studied, respectively. There were no dose-related differences (one-way analyses of variance (ANOVA), P<or= 0.05) in alpha, beta, total body clearance (Cl) and volume of distribution at steady state (V(ss)). The AUC increased significantly with the doses (249.7, 376.7 and 562.5 microg min ml (-1)). After non-compartmental analysis there were no significant differences in plasma elimination rate constant ( lambda), MRT and V(ss) as a function of dose, but these differences were significant for Cl, between 16 and 20 mg kg (-1), and AUC (one-way ANOVA, P<or= 0.05). The two-way ANOVA showed no significant differences between the values obtained for the three doses when lambda- beta, Cl, V(ss)and V(a)were compared while AUC showed significant changes. On the other hand, the pharmacokinetic analysis (compartmental and non-compartmental) showed significant differences in AUC, Cl, V(ss) and V(a), but there were no significant differences when lambda- beta were compared. The slow clearance of levamisole by rabbit lung compared to a high pulmonary blood flow rate makes the possibility of significant first-pass lung metabolism unlikely in this animal species.

Algorithms↗

PubMed2002

Laboratory evaluation of Mesocyclops annulatus (Wierzejski, 1892) (Copepoda: Cyclopidea) as a predator of container-breeding mosquitoes in Argentina.

In laboratory bioassays we tested the predatory capacity of the copepod Mesocyclops annulatus on Aedes aegypti and Culex pipiens larvae. A single adult female of M. annulatus caused 51.6% and 52.3% mortality of 50 first instar larvae of Ae. aegypti and Cx. pipiens respectively, in a 72 h test period. When alternative food was added to the containers, mortality rates declined to 16% and 10.3% for Ae. aegypti and Cx. pipiens respectively. When 50 first instar larvae of each of the two mosquito species tested were placed together with a single adult female of M. annulatus, mortality rates were 75.5% for Ae. aegypti larvae and 23.5% for Cx. pipiens larvae in a three day test period. Different density of adult females of M. annulatus ranged from 5 to 25 females produced mortality rates of Ae. aegypti first instar larvae from 50% to 100% respectively. When a single adult female of M. annulatus was exposed to an increasing number of first-instar Ae. aegypti larvae ranging from 10 to 100, 100% mortality was recorded from 1 to 25 larvae, then mortality declined to 30% with 100 larvae. The average larvae killed per 24 h period by a single copepod were 29.

Aedes↗

PubMed2002

[Human herpesvirus-6 circulation in healthy adults and oncologic patients].

The aim of this paper was to assess the prevalence of antibodies to HHV-6 in the general population and study the virus circulation among individuals with cancer, in order to analyze HHV-6 involvement in lymphoproliferative disorders. A total of 200 sera from the general population and 67 from patients with neoplasia were studied. The latter were divided in 3 groups: lymphoma/myeloma, leukemia and non-immune solid tumors. HHV-6 antibodies (IgG and IgM) were assayed by IFA and viral genomes were detected using nested PCR. The prevalence of the infection in the healthy population was 63.5% with a titer geometric mean (TGM) of 48.67 +/- 1.23. A control group was obtained by systematic sampling of the healthy population. Among the patients with neoplasia, the prevalence was 95.5%. In the lymphoma/myeloma group, TGM was 268.73 +/- 1.62; in the leukemia group it was 151.1 +/- 1.88 and in the non-immunogenic solid tumors group it was 95.67 +/- 1.57. Statistically significant differences were observed (p < 0.01) between the control group and the lymphoma/myeloma and leukemia groups. Serum IgM or free viral genomes were not detected in any serum sample. The antibody prevalence found in the general population documents the high circulation of this lymphotropic virus which could indirectly contribute to the pathogenesis of the lymphoproliferative disorder.

Adolescent↗

PubMedDate not supplied

[Effect of temperature on longevity and infection with the nematode Strelkovimermis spiculatus (Nemata: Mermithidae), a parasite of mosquitoes].

Strelkovimermis spiculatus is a common parasite of culicid species in Argentina. Effect of temperature on longevity and infectivity of juvenile preparasites of S. spiculatus was determined at 4, 10, 20 and 27 degrees C. Three containers with 100 ml of dechlorinate water and 300 preparasites (12 hour-old), were placed for each day and temperature, during 40 days (total = 480 containers). Survived preparasites were counted on 12 containers per day (three for each temperature). When number of survived preparasites was determined, second instar larvae of Aedes aegypti were added to each container in a 10:1 ratio (preparasites:mosquito) to determine infectivity of daily survived preparasites. Longevity of preparasites decreased at higher temperatures. Maximum longevity of preparasites maintained at 4, 10, 20 and 27 degrees C were 35, 30, 25 and 27 days, respectively. Survivorship of preparasites, exposed to the same temperatures, varied from 57% to 100% at day two, from 21% to 77% at day five and from 9% to 33% at day ten. Infectivity of preparasites maintained at temperatures from 4 to 27 degrees C was always higher than 70%. Extended longevity with maintenance of the infectivity capacity of preparasites, are important attributes to consider S. spiculatus an effective mean of controlling a large number of culicid species between 4 and 27 degrees C.

Animals↗