Dengue virus identification by transmission electron microscopy and molecular methods in fatal dengue hemorrhagic fever.

Dengue virus is the most significant virus transmitted by arthropods worldwide and may cause a potentially fatal systemic disease named dengue hemorrhagic fever. In this work, dengue virus serotype 4 was detected in the tissues of one fatal dengue hemorrhagic fever case using electron immunomicroscopy and molecular methods. This is the first report of dengue virus polypeptides findings by electron immunomicroscopy in human samples. In addition, not-previously-documented virus-like particles visualized in spleen, hepatic, brain, and pulmonary tissues from a dengue case are discussed.

Cost effectiveness of Aedes aegypti control programmes: participatory versus vertical.

We conducted an economic appraisal of two strategies for Aedes aegypti control: a vertical versus a community-based approach. Costs were calculated for the period 2000-2002 in three pilot areas of Santiago de Cuba where a community intervention was implemented and compared with three control areas with routine vertical programme activities. Reduction in A. aegypti foci was chosen as the measure of effectiveness. The pre-intervention number of foci (614 vs. 632) and economical costs for vector control (US$243746 vs. US$263486) were comparable in the intervention and control areas. During the intervention period (2001-2002), a 13% decrease in recurrent costs for the health system was observed. Within the control areas, these recurrent relative costs remained stable. The number of A. aegypti foci in the pilot areas and the control areas fell by 459 and 467, respectively. The community-based approach was more cost effective from a health system perspective (US$964 vs. US$1406 per focus) as well as from society perspective (US$1508 vs. US$1767 per focus).

Hidatidosis hepatopulmonar en una preescolar, caso clínico: case report / Hepatopulmonary hydatidosis in a preschool female: case report

Se denomina Hidatidosis a la zoonosis parasitaria que causa la infección de herbívoros o del hombre con el estado larval (hidátide) de parásitos del género Echinococcus. Objetivo: Revisión del tema y presentación del primer caso en Chile estudiado mediante técnicas de biología molecular. Caso Clínico: Preescolar de 3 años 9 meses procedente de Punta Arenas portadora de una hidatidosis múltiple de 6 quistes (4 pulmonares y 2 hepáticos), trasladada a la V Región para su tratamiento. Se realizó 3 cirugías y tratamiento médico asociado (Albendazol en dosis de 15 mg/kg/día vía oral) durante 73 días. Las hidátides extraídas fueron medidas, se efectuó estudio de fertilidad y vitalidad e identificación de cepa de Echinococcus granulosus mediante técnicas de biología molecular. La paciente mostró notable mejoría clínica e imagenológica, y mantuvo serología positiva. El tratamiento fue bien tolerado no presentando reacciones adversas. El tamaño de las hidátides fluctuó entre 6 y 11 cm de diámetro, todas fueron fértiles y vitales en diferente porcentaje y en todas se identificó cepa oveja de E. granulosus. De regreso en Punta Arenas, a los 4 meses se le detecta una nueva hidátide hepática que fue extirpada. El complejo manejo de este caso resultó exitoso.

Ten-year viability study on natural populations of Drosophila sibling species from Laguna Verde, Veracruz, México.

The generation of electricity in nuclear power plants produces an increase in background radiation that could possibly have some impact on the organisms that live in that area. In order to identify and quantify any such possible effect, the natural populations of two sibling species, D. melanogaster and D. simulans, that live in the immediate vicinity of the first Mexican Nuclear Power Plant were analyzed for a period of 10 years. Collections of flies were made at two sites, one close to and one farther from the power plant, during the pre and operational stages of the reactor, and their egg-to-adult viability was analyzed. The data obtained indicate that in both sites, the egg-to-adult viability was generally higher in D. melanogaster than in D. simulans. Further, a relationship was found between egg-to-adult viability and the season of the year (warm-wet or cool-dry season). Some differences were found between the two sites. It may be concluded that there is no negative impact on the Drosophila populations studied.

Serological evidence for recent exposure to Taenia solium in Venezuelan Amerindians.

This study examined the seroprevalence and serum antibody isotype profile for Taenia solium cysticercosis in an Amerindian community in the Amazonas state of Venezuela. An antigen-trapping enzyme-linked immunosorbent assay (Ag-ELISA) was used to detect viable cysticercosis. Indirect ELISA (Ab-ELISA) and enzyme-linked immunoelectrotransfer blot (EITB) was performed by using antigens prepared from T. solium metacestodes to detect anti-parasite antibodies. The Ag-ELISA and Ab-ELISAs revealed 64.7% and 79.0% seropositivity, respectively, in the Amerindian population. Immunoglobulin (Ig) M was the predominant antibody class, suggesting recent infection. In comparison sera from, clinically defined, hospital neurocysticercosis cases revealed only 27% seropositivity by Ag-ELISA, compared with 86-92% seropositivity by Ab-ELISA, and IgG4 was the predominant antibody subclass detected. The EITB antigen recognition patterns of the hospitalized patients were very similar to that of the Amerindians, confirming exposure to the parasite. These results, combined with the predominance of IgM antibody responses and the marked detection of secreted products of viable parasites, strongly suggest that recent exposure to T. solium had occurred in the Amerindian population.

Characterization of the HCV core virus-like particles produced in the methylotrophic yeast Pichia pastoris.

Little is known about the mechanism of hepatitis C virion assembly. So the capacity of the entire Hepatitis C virus core protein (HCcAg) produced in Pichia pastoris to form particles either in its native soluble state or after detergent treatment of HCcAg associated to cell debris were studied. Size exclusion chromatography suggested that HCcAg assembled into high molecular weight structures. HCcAg was also specifically recognized by a serum from a chronic HCV carrier patient. This antigen migrated with buoyant density values similar to those obtained for native nucleocapsid particles from infected patients when analyzed using sucrose density gradient centrifugation. The analysis by electron microscopy of purified HCcAg showed aggregates resembling virus-like particles (VLPs) with an average diameter of 30 nm. These results indicated that the HCcAg obtained from P. pastoris assembled into VLPs resembling HCV nucleocapsid particles in a mature stage. Such HCcAg aggregates characterized here could be a valuable tool to elucidate the mechanisms of HCV nucleocapsid assembly.

Adolescent illegal drug use: the impact of personality, family, and environmental factors.

This study examined the relationship between the domains of environmental factors, family illegal drug use, parental child-rearing practices, maternal and adolescent personality attributes, and adolescent illegal drug use. A nonclinical sample of 2,837 Colombian youths and their mothers were interviewed about intrapersonal, interpersonal, and environmental factors in their lives. Results indicated that certain environmental factors (e.g., violence, drug availability, and machismo), family drug use, a distant parent-child relationship, and unconventional behavior are risk factors for adolescent illegal drug use. As hypothesized, results showed that the adverse effects of family illegal drug use on adolescent drug use can be buffered by protective parental child-rearing practices and environmental factors, leading to less adolescent illegal drug use. Prevention and treatment efforts should incorporate protective environmental, familial, and intrapersonal components in order to reduce adolescent illegal drug use.

Plasmid DNA-recombinant Opc protein complexes for nasal DNA immunization.

The nasal mucosa may provide a simple, non-invasive route to deliver DNA encoding genes that stimulate a specific immune response. Based on this, a new approach using pCMVbeta-gal plasmid DNA complexed to the Opc meningococcal outer membrane protein was assayed for. Optimal conditions of interaction were established between recombinant Opc protein and pCMVbeta-gal plasmid DNA. Complexes were fully characterized by electrophoresis analysis, DNAse resistance assay and transmission electron microscopy. DNA-protein complexes were also evaluated in in vitro transfection experiments. After the characterisation of complexes, Balb/c mice were intranasal (i.n.) and intramuscularly (i.m.) immunized. The humoral immune response against beta-galactosidase was measured by ELISA. The proliferative response in the spleen lymph nodes was also measured. Complexes administered by i.n. route induced both systemic and mucosal antibody responses. This behavior was not observed with the naked DNA. Finally, a lymphoproliferative response specific to beta-galactosidase induced by DNA-protein complexes was also detected.

Surgical site infections in ambulatory surgery: a 5-year experience.

OBJECTIVES: To evaluate the ambulatory surgical site infection rate and risk factors associated with surgical site infection. METHODS: We conducted a case-control analysis of all ambulatory surgeries between January 1, 1993, and December 31, 1997. The frequency of surgical site infection per 100 surgeries was calculated. The odds ratio (OR) was estimated by using logistic regression analysis. SETTING: A 140-bed tertiary-care teaching hospital for adult patients with cancer. RESULTS: The study followed 1350 outpatient surgeries. Thirty-eight patients had a surgical site infection (rate per 100 surgeries: 2.8). The risk factors statistically associated with surgical site infection were postoperative antibiotics (OR = 7.5; 95% CI, 2.5-23.0), and surgical time >35 minutes (OR = 2.4; 95% CI, 1.1-5.5). CONCLUSIONS: The surgical site infection rate for same-day surgery at our hospital is within the limits reported in the literature and below the rates reported previously for inpatient surgeries at our hospital. Full review of medical records and microbiology reports at day 30 allowed us to identify infections that otherwise would have been missed. Postoperative antibiotics may increase the risk of infection.

Assembly of truncated HCV core antigen into virus-like particles in Escherichia coli.

Core protein is one of the most conserved and immunogenic of the hepatitis C virus proteins. Several pieces of experimental evidence suggest its ability for formation of virus like particles alone or in association with other viral proteins in mammalian or yeast cells with great similarity to those detected in patient sera and liver extract. In this work we report an Escherichia coli-derived truncated hepatitis C core protein that is able to aggregate. SDS-PAGE and size exclusion chromatography patterns bring to mind the aggregation of monomers of recombinant protein Co.120. The Co.120 protein migrated with buoyant density of 1.28 g/cm(3) when analyzed using CsCl density gradient centrifugation. Spherical structures with an average diameter of 30 nm were observed using electron microscopy. We report here that VLPs are generated when the first 120 aa of HCV core protein are expressed in E. coli.

[Diagnosis of tuberculosis meningitis by detection of adenosine deaminase activity and amplification of nucleotide sequences with PCR]. / Diagnóstico de meningitis tuberculosa por la determinación de la actividad de adenosina deaminasa y la amplificación de secuencias nucleotídicas por PCR.

Tuberculous meningitis (TBM) is the most severe and lethal form of tuberculosis. The rapid bacteriological diagnosis with the conventional techniques is nearly impossible in TBM. There for many patients are treated with anti-TBC drugs without a definitive diagnosis. A more fast and accurate diagnostic method is necessary, in order to initiate the treatment on time to prevent the irreversible neurologic sequel or death. We evaluated the use of two rapid methods: Adenosine deaminase activity (ADA) and polymerase chain reaction (PCR) for IS6110 and mtp40 sequences on cerebrospinal fluid (CSF) from chronic meningitis patients. For ADA activity > 8.0 U/L the sensibility and specificity was 80% and 91%. PCR sensibility was 80% and specificity 97%. ADA activity and PCR on CSF could be specially useful as complementary tools in the early diagnosis of TBM.

[Cuban epidemic neuropathy: the risk factors in the population]. / Neuropatía epidémica cubana: algunos factores de riesgo en la población.

A cross-sectional study was conducted in 1995 in a representative sample of the Cuban population aged 15 years or over with the objective of describing prevalence and characteristics of smoking, alcohol consumption, and physical inactivity in the urban population which could have been affected by epidemic neuropathy from 1991-1993. The sampling was stratified at provincial and municipal levels and then by cluster samplings. 93% of the sample was surveyed (14 300 people). 30% of the population aged 17 years and over smoked; the highest proportion of smokers was located in 40-49 years age group; men smoked more than woman regardless of age. The prevalence of alcohol consumption was 45.2% in which Eastern provinces exceeded the domestic average with males predominating. The prevalence of physical inactivity at national level was 33%, 25.7% for males and 39.8% for females. 47.3% of males and 25.4% of females classified as physically active because of their useful extra activity. It was considered that irregular relationships between these 3 risk factors and the incidence of epidemic neuropathy at the ecological level make it think that, although they have a real influence on the determinants of the disease, other factors may also better account for the occurrence of these cases.

[Trends of hospital infections at an oncology center, 1986-1996]. / Tendencias de infecciones intrahospitalarias en un centro oncológico, 1986-1996.

OBJECTIVE: To describe the results of ten years of nosocomial infection (NI) surveillance in an oncology center. MATERIAL AND METHODS: This is a descriptive study of the Infection Control and Surveillance Program Committee at the Instituto Nacional de Cancerología, conducted in 1997. From June 1986 to December 1996, we surveyed 62,733 hospital discharge records. Criteria used to classify nosocomial infections were those outlined in 1972 by the Centers for Disease Control and Prevention, Atlanta (GA). Survey data were collected through review of microbiology chart records and of hospital chart records of febrile patients, patients receiving antibiotics, and patients visited after surgery. We calculated the rates of NI as the number of infections/100 discharges. RESULTS: The rate of NI per 100 discharges was 4.4 in 1986, 7.7 in 1987, 8.1 in 1988, 5.9 in 1989, 4.6 in 1990, 5.1 in 1991, 4.3 in 1992, 5.4 in 1993, 7.6 in 1994, 7.1 in 1995 and 8.5 in 1996. Escherichia coli was the microorganism most frequently isolated. From 1987, an increase of almost seven times in fungi isolations as well as enterococci was observed. CONCLUSIONS: An increasing trend in NI rates was observed in the last four years, probably related to multiple factors such as improved surveillance (better reporting) and a real increase in the frequency of NI.

[Simplified method for the processing of sputum in the diagnosis of tuberculosis]. / Método simplificado para el procesamiento de esputos en el diagnóstico de la tuberculosis.

OBJECTIVE: We evaluated a simplified method for processing three serial sputum samples as a single sample, and compare the results with those obtained when processing three samples individually. MATERIAL AND METHODS: During a 32-week period, we studied 867 sputum samples from 289 patients with pulmonary tuberculosis suspicious. Samples from 148 patients (n = 444) were processed by simplified method, and samples from 141 patients (n = 423) were processed by individually method. All cultures were processed by ESP Culture System II (Difco Laboratories, USA). RESULTS: Seven mycobacterium's strains were isolated by individually method. Simplified method detected another seven strains. In both cases, four strains were identified as Mycobacterium tuberculosis. Mean time to detection mycobacteria were 21.5 and 24 days for simplified and individually method, respectively. Cultures from 21 patients were contaminated (11 patients by simplified method and 10 patients by individually method). Mean time to detection contaminated cultures were 8 days and 7.5 days for simplified and individually method, respectively. CONCLUSION: Simplified method may be a useful alternative in laboratories that must handle increasing numbers of samples, without decline in diagnostic performance.

Surgical site infections at the National Cancer Institute in Mexico: a case-control study.

OBJECTIVES: To quantify the surgical infection rate and to identify risk factors associated with surgical site infection. METHODS: We conducted a case-control study of all surgical patients between January 1, 1993, and June 30, 1994. The frequency of surgical site infection per 100 surgeries was calculated. The odds ratio (OR) was estimated by using logistic regression analysis. SETTING: A 130-bed tertiary-care teaching hospital for adult patients with cancer. RESULTS: The study followed 3372 surgeries. Three hundred thirteen patients had a surgical site infection (rate per 100 surgeries: 9. 30). The risk factors associated with surgical site infection were diabetes mellitus (OR = 2.5, 95% confidence interval [CI] = 1.27-4. 91), obesity (OR = 1.76, 95% CI = 1.14-2.7), presence of surgical drains for >5 and <16 days (OR = 1.84, 95% CI = 1.02-3.31), and presence of surgical drains for >/=16 days (OR = 2.14, 95% CI = 1. 0-4.6). The bacteria most frequently isolated were Escherichia coli 38 (21.8% of the total of microorganisms found), Pseudomonas sp 22 (12.6%), Staphylococcus aureus 16 (9.2%), and coagulase-negative Staphylococcus 25 (13.6%). The coexistence of other nosocomial infections was greater among the cases (OR = 1.8, 95% CI = 1.1-3.1) than in the control group. CONCLUSIONS: The surgical site infection rate in our hospital is slightly higher than the rates reported for general hospitals. The risk factors associated with surgical site infection are similar to those previously reported. Diabetes mellitus, obesity, and prolonged presence of a surgical drain increased the risk of infection.

Population dynamics and stock assessment for Octopus maya (Cephalopoda: Octopodidae) fishery in the Campeche Bank, Gulf of Mexico.

The octopus (Octopus maya) is one of the most important fish resources in the Mexican Gulf of Mexico with a mean annual yield of 9000 ton, and a reasonable number of jobs created; O. maya represents 80% of the total octopus catch, followed by Octopus vulgaris. There are two artisanal fleets based on Octopus maya and a middle-size fleet that covers both species. Catch-at-length structured data from the artisanal fleets, for the 1994 season (August 1st to December 15th) were used to analyze the O. maya population dynamics and stock and to estimate the current level of exploitation. Von Bertalanffy growth parameters were: L infinity = 252 mm, mantle length; K = 1.4 year-1; oscillation parameters C = 1.0, WP = 0.6; and tz = 0.842 years. A rough estimate of natural mortality was M = 2.2, total mortality from catch curve Z = 8.77, and exploitation rate F/Z = 0.75. This last value suggests an intensive exploitation, even when yield per recruit analysis indicates both fleets may increase the minimum legal size on about 10% to increase yields. The length-based VPA also shows that the stock is being exploited under its maximum acceptable biological limit. These apparently contradictory results are explained by biological and behavioral characteristics of this species. Because most females die after reproduction, a new gross estimation of natural mortality was computed as M = 3.3. The new estimate of exploitation rate was F/Z = 0.57. This new value coincides with results from the length-VPA and the Thompson and Bell methods, the former suggesting that a reduction of 20% in fishing mortality may provide larger yields. This fishery resource is fully exploited and current management measures must be revised to sustain and probably optimize yields.

[Surveillance of surgical wound infections. 18-month experience in the Instituto Nacional de Cancerología]. / Vigilancia de las infecciones de herida quirúrgica. Experiencia de 18 meses en el Instituto Nacional de Cancerología.

OBJECTIVE: To calculate the surgical site infection (SSI) rates with a surgical prospective surveillance program and postdischarge follow-up. MATERIAL AND METHODS: During a 18 months period (01/01/93 to 04/30/94), a surgical wound surveillance program followed on the surgeries practiced at the National Institute of Cancerology, a referral center situated in Mexico City. Rates per 100 surgeries were calculated for the surgical services and for each of the wound class strata. The SS's were classified according to the 1992 Center for Disease Control definitions for surgical infections. RESULTS: Three thousand, three hundred and severity-two surgeries were assessed; 313 were diagnosed as infected: 140 (44.7%) were superficial incisional, 137 (43.7%) were deep incisional and 36 (11.5%) were organ and space infections. The SSI rate for this period was 9.28%; for the clean, clean-contaminated, contaminated and dirty surgeries the rates were 7.35, 10.5, 17.3 and 21.5% respectively. The rates for each service were: gastroenterology, 14.13%; breast tumors, 11.08%; mixed tumors, 10.98%; gynecology, 9.06%; urology, 7.38%; head and neck, 7.13%, and thoracic surgery, 1.81%. On average SSI were detected at 11.6 +/- 6.23 days, eighty-five (27.16%) were diagnosed while the patient was in-hospital, the remaining 228 (72.84%) were detected after discharge. In 134 (42.8%) patients a culture was obtained. The bacteria most frequently found were: E. coli, 38 (22.5%); coagulase negative Staphylococci, 23 (13.6%); Pseudomonas sp., 22 (13%); S. aureus, 16 (9.4%); and Enterococcus, 13 (7.7%). CONCLUSIONS: The prospective surveillance program with a follow-up for 30 days increased by 400% the chance to identify a SSI. The SSI rate for clean and clean-contaminated surgeries are above the rates reported in the literature.

Ultrastructural and immunocytochemical evidences of core-particle formation in the methylotrophic Pichia pastoris yeast when expressing HCV structural proteins (core-E1).

Particulate antigens of the Hepatitis C virus (HCV) are reported for the first time by transmission electron microscopy in Pichia pastoris. The yeast was cloned to express the first 339 NH2-terminal amino acids of the HCV polyprotein (C-E1.339 polypeptide). The C-E1.339 polypeptide covers the putative 191 aa of the core protein (aa 1-191) and 148 aa of the E1 envelope antigen (aa 192-339). Virus-like particles (VLP) with diameters ranging from 20 nm to 30 nm were specifically observed in those cells expressing the HCV polyprotein. The VLP appeared along the membrane of the endoplasmic reticulum, but were fundamentally localized in vacuoles, either free or inside autophagic bodies. Clustered particles, chains of particles, high-density reticular structures, and crystalloid bodies were also detected, the last one being an orderly arrangement of particles with 20 nm diameters. The crystal-associated particles are well differentiated from the intracellular VLP because of their uniform size and shape. We argue that membrane components are retained in the architecture of the VLP, conferring to this particle certain heterogeneity. Both kinds of particles, the VLP formed after treatment with NP-40 and the crystal-associated particles, were core protein-positives. Whether they reflect mature HCV nucleocapsid or intermediary states in the viral nucleocapsid morphogenesis remains unknown. We conclude that, like mammalian cell lines, the P. pastoris yeast could be an appropriate host for the analysis of HCV polyprotein processing and, eventually, virus assembly.

The role of parents in protecting Colombian adolescents from delinquency and marijuana use.

OBJECTIVES: To identify general and differentiating risk and protective factors from domains of culture and ecology, peer, family, and personality, related to adolescent delinquency and marijuana use, and to study the protective role of the parent-child mutual attachment in offsetting cultural and ecological risk factors, leading to less delinquency and marijuana use. DESIGN: Cross-sectional analyses of interview data collected in Colombia. PARTICIPANTS: A total of 2837 Colombian adolescents, 12 to 17 years of age. SETTING: Adolescents were interviewed in their homes. MAIN MEASURES: Independent variables included measures from 4 domains: culture and ecology, peer, family, and personality. The dependent variables were delinquency and marijuana use. RESULTS: Several risk factors, such as tolerance of deviance and sensation seeking, were similarly related to both delinquency and marijuana use, suggesting that a common cause underlies the propensity to engage in different deviant behaviors. Some risk factors were more involved in delinquency and other risk factors were more highly related to the adolescent's marijuana use. Finally, when violence is endemic and illegal drugs are readily available, a close parent-child bond was capable of mitigating these risk factors, leading to less marijuana use and delinquency. CONCLUSIONS: The findings have implications for public health policy related to interventions in countries in which violence and drug use are prevalent. The results point to interventional procedures aimed at adolescents vulnerable to marijuana use and delinquency as well as efforts aimed at specific vulnerabilities in these areas. For example, reducing the risk factors and enhancing the protective factors for marijuana use and delinquency may result in less adolescent marijuana use and delinquency.