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Biomedical subjects

J L Sanchez

Publications and source records attributed to J L Sanchez.

At least 19 recordsLinked to original sources
PubMed2007

Prevalence and correlates of risky sexual behaviors among injection drug users in Tashkent, Uzbekistan.

The objective of this paper is to describe prevalence and correlates of sexual risk behaviors among injection drug users (IDUs) in Tashkent, Uzbekistan. Participants in this cross-sectional study completed a questionnaire detailing sociodemographic, medical and drug and sexual risk behaviors and HIV antibody testing. Of 701 IDUs surveyed, only 20.5% reported consistent condom use, which was more likely for women. Prior sexually-transmitted infection (STI) diagnosis was reported by 36.2% of participants and was associated with early (</=18 years) drug initiation, group drug use, being older, higher educational level, marriage, needle sharing, multiple sex partners in the preceding month and daily injection use. Having multiple partners in the preceding month was common (29.71%) and related to employment, consistent condom use with regular partners and STI self-treatment in multivariate logistic regression. Participants with a history of sharing needles were less likely to have had multiple partners in the previous month. Risky sexual behaviors are common and interrelated with risky injection habits among IDUs in Tashkent, Uzbekistan, representing a continued threat of infection with HIV and other blood-borne agents.

Adolescent↗
PubMed2006

Seroprevalence of and risk factors for HIV-1 infection among female commercial sex workers in South America.

OBJECTIVE: Assessment of HIV prevalence and associated risk behaviours among female commercial sex workers (FCSW) across major cities in South America. METHODS: Seroepidemiological, cross sectional studies of 13 600 FCSW were conducted in nine countries of South America during the years 1999-2002. Participants were recruited in brothels, massage parlours, hotels, and streets where anonymous questionnaires and blood samples were collected. HIV infection was determined by enzyme linked immunosorbent assay (ELISA) screening and western blot confirmatory tests. RESULTS: The overall HIV seroprevalence was 1.2% (range 0.0%-4.5%). The highest HIV seroprevalences were reported in Argentina (4.5%) and Paraguay (2.6%); no HIV infected FCSW were detected in Venezuela and Chile. Consistent predictors of HIV seropositivity were: (1) a previous history of sexually transmitted infections (STI, AORs = 3.8-8.3), and (2) 10 years or more in commercial sex work (AORs = 2.2-24.8). In addition, multiple (> or =3) sexual contacts (AOR = 5.0), sex with foreigners (AOR = 6.9), use of illegal drugs (AOR = 3.2), and marijuana use (AOR = 8.2) were associated with HIV seropositivity in Southern Cone countries. CONCLUSIONS: Consistently low HIV seroprevalences were detected among FCSW in South America, particularly in the Andean region. Predictors of HIV infection across the continent were STI and length of commercial sex work; however, use of illegal drugs, especially marijuana, and sexual contacts with foreigners were also found to be associated risk factors in the Southern Cone region. Interventions for the control of HIV and other STI need to be region and country specific; drug use appears to have an ever increasing role in the spread of HIV among heterosexually active populations.

Adult↗
PubMed2005

Molecular epidemiology of HIV type 1 in Chile: differential geographic and transmission route distribution of B and F subtypes.

We examined the genetic makeup of 221 HIV-1 strains from Chilean persons living with HIV/AIDS by HMA and DNA sequencing of the env gene: 143 cases were infected by sexual contact with an already-infected partner, 76 were infected by mother-to-child transmission, and 2 were transfusion related. We found env HIV-1 subtype B in 202 cases (91.4%) and subtype F in 19 cases (8.6%). Subtype B strains were found throughout the country whereas subtype F viruses were predominantly found in cases from the metropolitan/central to the northern regions of Chile (p < 0.01). Chilean F subtypes clustered in two different groups: viruses from the central region clustered with F subtypes from Argentina, Uruguay, and Brazil, and viruses from the northern region, which independently segregated from other South American and European F strains. All of the 59 men having sex with men (MSM) were infected with B subtype strains whereas 7 (9.2%) and 12 (15.8%), respectively, of heterosexually infected females and children were infected with F subtype strains (p < 0.01). It appears that F subtype strains have been introduced into Chile by separate heterosexual transmission events from other nearby countries in the Southern Cone whereas B subtype strains have continued to persist predominantly among MSM.

Adult↗
PubMed2004

Documentation of subtype C HIV Type 1 strains in Argentina, Paraguay, and Uruguay.

HIV subtypes B, F, and BF recombinants have been previously reported in South America. This report describes the presence of HIV-1 subtype C infection in the countries of Argentina, Uruguay, and Paraguay dating back to at least 1999. Surveillance for uncommon non-B/non-F subtype viruses circulating in South America has been conducted in samples obtained from nine countries. Peripheral blood mononuclear cells (PBMC), dried filter paper (FP), and fresh blood (FB) samples were collected from HIV-positive patients from Ecuador, Colombia, Venezuela, Peru, Chile, Bolivia, Argentina, Uruguay, and Paraguay. From a total of 2962 HIV seropositive samples examined during a 9-year period (1995-2003), only 11 (0.4%) were found to be infected with non-B/non-F HIV variants. Eight of these 11 strains were determined to be subtype C by heteroduplex mobility assay (HMA). Five of these 8 strains were further characterized by sequencing and phylogenetic analysis of the protease (Pro) and reverse transcriptase (RT) region of the genome and two were sequenced full length. One of the strains was found to be a unique BC recombinant. The spread of a third subtype of HIV, subtype C, should raise the question of its potential future role in the HIV epidemic in this region.

Adult↗
PubMed2004

Seroprevalence of and risk factors for HIV-1 infection among South American men who have sex with men.

OBJECTIVES: Sex among men constitutes an important route of transmission for HIV type 1 (HIV-1) in Latin America. Seeking better understanding of risk behaviours in this region, we determined the seroprevalence, potential risk factors, and geographic distribution of HIV-1 among groups of men who have sex with men (MSM). METHODS: Seroepidemiological, cross sectional studies of 13,847 MSM were conducted in seven countries of South America during the years 1999-2002. Volunteers were recruited in city venues and streets where anonymous questionnaires and blood samples were obtained. HIV-1 infection was determined by enzyme linked immunosorbent assay (ELISA) screening and western blot (WB) confirmatory tests. RESULTS: HIV-1 seroprevalence varied widely (overall 12.3%, range 11.0%-20.6%). The highest HIV-1 seroprevalence was noted in Bolivia (20.6%) and the lowest in Peru (11.0%). Predictors of HIV-1 infection varied among countries; however, a history of previous sexually transmitted disease (STD) was associated with a consistent increased risk (ORs=1.9-2.9, AORs=1.8-2.7). Multiple weekly sexual contacts was found to represent a secondary risk factor in Ecuador, Peru, and Argentina (ORs=1.6-2.9, AORs=1.6-3.1), whereas use of drugs such as cocaine was found to increase risk in Bolivia, Uruguay, and Paraguay (ORs=2.5-6.5, AORs=2.6-6.1). CONCLUSION: The results of this study illustrate an elevated HIV-1 seroprevalence among MSM participants from Andean countries. A previous STD history and multiple partners predicted HIV-1 infection in the seven countries of South America. In Southern Cone countries, HIV-1 infection was also associated with use of illegal drugs such as cocaine.

Adolescent↗
PubMed2003

Circulating recombinant form CRF02_AG in South America.

With the objective of monitoring the distribution of HIV-1 subtypes and circulating recombinant forms (CRFs)in South America, population-based surveillance studies were performed in seven countries. Peripheral blood mononuclear cell, filter paper, fresh blood, and cocultivation samples were collected from HIV-positive patients from Colombia, Ecuador, Peru, Bolivia, Chile, Argentina, and Uruguay, during a 7-year period(1995-2001). DNA was prepared and HIV envelope subtypes were determined by heteroduplex mobility as-say and DNA sequencing from 1289 HIV-positive samples. While subtypes B and F were the most commonly observed subtypes, two CRF02_AG strains were detected, in Ecuador. This is the first report of the existence of this CRF in South America.

Adult↗
PubMed2002

Levels and risk assessment for humans and ecosystems of platinum-group elements in the airborne particles and road dust of some European cities.

Traffic is the main source of platinum-group element (PGE) contamination in populated urban areas. There is increasing concern about the hazardous effects of these new pollutants for people and for other living organisms in these areas. Airborne and road dusts, as well as tree bark and grass samples were collected at locations in the European cities of Göteborg (Sweden), Madrid (Spain), Rome (Italy), Munich (Germany), Sheffield and London (UK). Today, in spite of the large number of parameters that can influence the airborne PGE content, the results obtained so far indicate significantly higher PGE levels at traffic sites compared with the rural or non-polluted zones that have been investigated (background levels). The average Pt content in airborne particles found in downtown Madrid, Göteborg and Rome is in the range 7.3-13.1 pg m(-3). The ring roads of these cities have values in the range 4.1-17.7 pg m(-3). In Munich, a lower Pt content was found in airborne particles (4.1 pg m(-3)). The same tendency has been noted for downtown Rh, with contents in the range 2.2-2.8 pg m(-3), and in the range 0.8-3.0 and 0.3 pg m(-3) for motorway margins in Munich. The combined results obtained using a wide-range airborne classifier (WRAC) collector and a PM-10 or virtual impactor show that Pt is associated with particles for a wide range of diameters. The smaller the particle size, the lower the Pt concentration. However, in particles <PM-10, some of the highest values correspond to the fraction <0.39 microm. Considering an average Pt content in all particles of approximately 15 pg m(-3), which is representative for all countries and environmental conditions, the tracheobronchial fraction represents approximately 10% and the alveolar fraction approximately 8% of the total particles suspended in air. However, from the environmental risk point of view, an exposure to PGEs in traffic-related ambient air is at least three orders of magnitude below the levels for which adverse health effects might theoretically occur (of approx. 100 ng m(-3)). Therefore, today inhalation exposure to PGEs from automotive catalysts does not seem to pose a direct health risk to the general population. Even though the data available today indicate no obvious health effects, there are still a number of aspects related to PGEs and catalysts that justify further research. First, continual monitoring of changes in PGE levels in air and road dust is warranted, to make sure that there is no dramatic increase from today's levels. Secondly, more detailed information on the chemical composition of the PGE-containing substances or complexes leaving the catalyst surface and the size distribution of the PGE-containing particles released during driving will facilitate a more in-depth human risk assessment.

Air Pollutants↗
PubMed2002

An observational clinic-based study of diarrheal illness in deployed United States military personnel in Thailand: presentation and outcome of Campylobacter infection.

Campylobacter is a leading cause of traveler's diarrhea in Thailand. Since resistance to quinolones is high among Campylobacter isolates, empiric therapy with quinolones for traveler's diarrhea may be ineffective in this region. We conducted an observational study among 169 U.S. military personnel with acute diarrhea and compared their microbiologic findings to those of 77 asymptomatic personnel deployed to Thailand in May 1998. Of 146 pathogenic bacterial isolates, the most common were nontyphoidal Salmonella (n = 31), enterotoxigenic Escherichia coli (n = 24), and C. jejuni/coli (n = 23). Campylobacter was strongly associated with disease (odds ratio = 5.9; 95% confidence interval = 1.3-37.3), with a more severe clinical presentation, and with a reduced functional ability at presentation (P = 0.02). In vitro resistance to ciprofloxacin was observed in 96% of the Campylobacter isolates. Sub-optimal treatment response to ciprofloxacin was observed in 17% of the cases of Campylobacter infection versus 6% due to other causes. These results highlight the importance of Campylobacter as a cause of severe traveler's diarrhea in Thailand and illustrates the ongoing problem with antibiotic-resistant strains and associated treatment problems.

Adult↗
PubMed2001

Relationship of cytomegalovirus viral load in blood to pneumonitis in lung transplant recipients.

We developed a multiplex, quantitative, real-time, polymerase chain reaction assay for cytomegalovirus (CMV) and used it to measure the CMV viral load in weekly blood specimens from 43 lung transplant recipients. The median viral load in blood samples immediately preceding bronchoscopy was 1150 copies/microg human DNA for 12 subjects with pneumonitis compared to 91 copies for 31 subjects without (P=0.02, Mann-Whitney U test). Each log10 increase in CMV viral load resulted in an increase of 1.92 in the odds ratio for CMV pneumonitis (95% confidence interval 1.03-3.56). CMV viral load was elevated (>100 copies/microg human DNA) for a median of 21 days before bronchoscopy in those subjects with pneumonitis versus 0 days in those without (P=0.004). We conclude that the risk of CMV pneumonitis after lung transplantation is related to the level of CMV DNA in blood. Quantitative PCR should be evaluated prospectively for the preemptive management of CMV in lung transplant recipients.

Computer Systems↗
PubMed2001

Platinum and rhodium distribution in airborne particulate matter and road dust.

In this work the platinum and rhodium content in the atmosphere of Madrid was monitored for 1 year at seven different sites. Samples were taken with medium volume PM-10 collectors (< 10 microm) for 48 h and analysed by ICP-MS. The Pt and Rh content was dependent on the sampling site, ranging from < 0.1 to 57.1 and < 0.2 to 12.2 pg m(-3) with a medium value of 12.8 and 3.3 pg m(-3), respectively. These results show that the Pt and Rh content in airborne samples depends on the traffic density per day and also on medium driving speed. Road dust < 63 microm was analysed at the same time and at the same location. The Pt and Rh content at the six sites analysed was in the 31-2252 and 11-182 ng g(-1) range with an average of 317 and 74 ng g(-1), respectively. The average Pt/Rh ratio obtained was 4.3. similar to that obtained for airborne particles (4.0), and agrees with that of the more commonly used gasoline car catalyst [J.J. Mooney, Encyclopaedia of Chemical Technology (1996) 982]. Platinum distribution as a function of particle size in airborne particulate matter was also studied, by sampling with two high-volume sample collectors, a five-stage WRAC (from 10 to 65.3 microm and total) and a seven-stages PM-10) cascade impactor (from 9 to < 0.39 microm). Platinum is associated with a wide range of particle diameters. Due to the ultratrace level of Pt in airborne samples, its distribution in the atmosphere could not be considered as homogeneous. No trend could be established in Pt distribution in the different fractions, except that in most cases the highest value of Pt was obtained in the < 0.39-microm fraction. The Pt content was usually high in airborne samples when the Pb, Ce, Zr and Hf content was also high, thus confirming that the source of these pollutants is from traffic.

Air Movements↗
PubMed2001

Epidemic of adenovirus-induced respiratory illness among US military recruits: epidemiologic and immunologic risk factors in healthy, young adults.

Adenovirus (Ad)-induced acute respiratory illnesses resurged among civilian adults and selected military training populations in the United States during the late 1990s. We examined the epidemiologic and immunologic correlates of Ad-induced respiratory illnesses during a large outbreak at an Army basic training installation in southeast United States during a 9-day period in November 1997. A total of 79 recruits hospitalized with acute respiratory illnesses were evaluated during the outbreak period; confirmation of Ad infection by isolation of Ad-like cytopathic agents from throat cultures was detected in 71 (90%) of these patients. Serotyping of 19 (27%) of these 71 isolates identified the etiologic agent to be Ad type 4 (Ad4). In addition, 30 (81%) of 37 patients in whom paired sera were collected demonstrated significant increases (i.e., 4-fold or higher) in serum anti-Ad4 neutralizing antibodies. Anti-Ad4 immunity in new recruits was found to be very low (15 to 22%). A case-control study involving 66 of the 79 hospitalized cases and 189 non-ill controls from the same units was conducted. A lower risk of hospitalization for acute respiratory illnesses was documented for female recruits (odds ratio[OR] = 0.47, P <.05) whereas, a higher risk was noted for smokers (OR = 1.89, P <.05). Unit (training company) attack rates as high as 8 to 10% per week were documented and the outbreak quickly subsided after live, oral Ad types 4 and 7 vaccination was resumed in November 1997. Re-establishment of a military Ad vaccination program is critical for control of Ad-induced acute respiratory illnesses.

Acute Disease↗
PubMed2001

Outcome of adolescent trauma admitted to an adult surgical intensive care unit versus a pediatric intensive care unit.

BACKGROUND: Institutional protocol designates the adult trauma service as the primary manager of all adolescent traumas (age 14-18 years) unless admission to the pediatric intensive care unit (PICU) occurs. In the PICU, primary care becomes the responsibility of the pediatric intensivist, with trauma service as a consultant. The purpose of this study was to identify differences in the management of adolescent trauma between the pediatric intensivist in the PICU, and the adult trauma team in the surgical intensive care unit (SICU). METHODS: From January 1993 to January 1998, the medical records of all adolescent trauma patients requiring intensive care unit (ICU) management were reviewed. Depending on bed availability, patients younger than 16 were admitted to the PICU, and those 16 or older to the SICU. Demographic data obtained were age, sex, race, mechanism of injury, length of stay (LOS), ICU length of stay, days on mechanical ventilation, intubation, tracheotomy, intracranial pressure monitor, and Swan-Ganz catheter placement. Home discharge, rehabilitation placement, and death were recorded. Morbidity was measured using Injury Severity Score methodology, Pediatric Trauma Score, and Pediatric Risk of Mortality. RESULTS: One hundred nine completed records were reviewed (SICU, n = 58; PICU, n = 51). There was no statistical difference in sex, race, mechanism of injury, ICU LOS, tracheotomy, and intracranial pressure monitor placements. There was no difference in morbidity, as measured by Injury Severity Score, Pediatric Trauma Score, and Pediatric Risk of Mortality score or in outcome measurements (death, rehabilitation placement). SICU patients were older (SICU, 16.9 +/- 1.0 years; PICU, 15.4 +/- 1.0 years; p < or = 0.1 Mann-Whitney U test), more likely to be intubated (SICU, n = 42; PICU, n = 24; p < or = 0.05 Fisher's exact test), more likely to have pulmonary artery catheter placement (SICU, n = 7; PICU, n = 0), and had longer LOS (SICU, 12.2 +/- 10.6; PICU, 9.8 +/- 14.1; p < or = 0.03 Mann-Whitney U test). CONCLUSION: Adolescent trauma patients admitted to the PICU were less likely to be intubated or have a Swan-Ganz catheter placed. They had decreased LOS and days of mechanical ventilation. There was no difference in outcome measurements.

Adolescent↗
PubMed2001

Serosurvey of Borrelia burgdorferi infection among U.S. military personnel: a low risk of infection.

A serosurvey of 9,673 United States military personnel was conducted to estimate infection rates with Borrelia burgdorferi sensu stricto, which is the cause of Lyme disease in the United States. Initial screening of sera from 9,673 military personnel on active duty in 1997 was performed by enzyme-linked immunosorbent assay (ELISA); supplemental testing of all ELISA-positive sera was performed by Western blot. Initial screening identified 1,594 (16.5%) ELISA-positive samples, but only 12 (0.12%, 95% confidence interval [CI] = 0.05-0.19%) were confirmed by Western blot. Antecedent serum samples collected from 1988 to 1996 were available for 7,368 (76%) subjects, accounting for 34,020 person-years of observation. Just two of the nine Western blot-positive individuals for whom antecedent samples were available seroconverted during military service for an annual incidence rate of six seroconversions per 100,000 persons (95% CI = 0.7-21.5). The risk of Lyme disease in the U.S. military population was found to be low. Although there may be sub-groups of military personnel who could potentially benefit from vaccination, force-wide use of the Lyme disease vaccine is not warranted.

Adolescent↗
PubMed2001

Health assessment of U.S. military personnel deployed to Bosnia-Herzegovina for operation joint endeavor.

In anticipation of U.S. forces deploying to Bosnia-Herzegovina, plans were established to conduct medical surveillance of all military service members. This surveillance would provide the Department of Defense with an overview of the hospitalization and outpatient morbidity experience of U.S. forces. Standardized collection of medical data from all U.S. camps using 14 diagnostic categories based on International Classification of Diseases, 9th Revision, codes began in March 1996. Special assessments for hantavirus and tick-borne encephalitis (TBE) infection risk were also conducted. The average disease and nonbattle injury rate for U.S. forces was 7.1 per 100 soldiers per week. Injuries accounted for 28% of medical visits, whereas undefined/other visits accounted for 33%. The majority of remaining visits were for respiratory (14%), dermatologic (10%), and gastrointestinal (6%) complaints. There was one confirmed and one suspected case of hemorrhagic fever with renal syndrome; only 0.1% of individuals (2 of 1,913) tested seroconverted to hantavirus during deployment. No cases of TBE were reported, and the overall low seroconversion rate (0.42%, 4 seroconversions among 959 unimmunized personnel) reflected a very low risk of infection with TBE-related viruses. Operation Joint Endeavor and follow-on Operations Joint Guard and Joint Forge have been extremely healthy deployments.

Bosnia and Herzegovina↗
PubMed2001

Investigation of a cluster of Legionella pneumophila infections among staff at a federal research facility.

An epidemiologic investigation was conducted in response to a case of Legionella pneumonia in a scientist working at a federal research facility. A survey of 80 individuals working at the facility revealed that 13 (16%) had sustained prior infections with Legionella pneumophila serogroup 1 (Lps1) as measured by anti-Lps1 antibodies. Antibody-positive individuals' offices clustered around an air cooling tower and a heating, ventilation, and air conditioner unit (odds ratio = 5). On multivariate logistic regression analysis, individuals of non-white race (adjusted odds ratio = 8) and smokers (adjusted odds ratio = 36) were also found to be at higher risk of past infection. Marked Legionella growth was noted in the cooling tower's water reservoir and potable hot water system, where suboptimal operating temperatures were noted. Subsequent increase in the hot water temperatures as well as a complete renovation of the affected building's air handling and potable water systems led to a reduction in Legionella species colonization.

Adult↗
PubMed2000

Two-year study of the protective efficacy of the oral whole cell plus recombinant B subunit cholera vaccine in Peru.

The protective efficacy of an oral inactivated whole cell Vibrio cholerae plus recombinant B subunit cholera vaccine was determined against El Tor cholera among Peruvian children and adults (2-65 years old) in a randomized, double-blind manner. Study subjects received 2 doses of vaccine or placebo 2 weeks apart, followed by a booster dose 10 months later. Surveillance for cholera was performed actively, with 2 visits per week to each household, and passively, at a local hospital. Stool samples were collected during diarrhea episodes and were cultured for V. cholerae. A total of 17,799 persons received 2 doses of vaccine or placebo, and 14,997 of these persons received the booster dose. After 2 doses (first surveillance period), V. cholerae biotype O1 was isolated from 17 vaccinees and 16 placebo recipients, demonstrating vaccine efficacy (VE) of -4%. After 3 doses (second surveillance period), V. cholerae O1 was isolated from 13 vaccinees and 32 placebo recipients, demonstrating VE of 61% (95% confidence interval ¿CI, 28%-79%). In the second surveillance period, the VE for illness requiring hospitalization was 82% (95% CI, 27%-96%). VE was also higher for persons >15 years old (VE, 72%; 95% CI, 28%-89%).

Administration, Oral↗
PubMed2000

Detection of adenoviruses (AdV) in culture-negative environmental samples by PCR during an AdV-associated respiratory disease outbreak.

Since 1954, adenoviruses (AdV) have been recognized as an important cause of acute respiratory disease (ARD) among U.S. military recruits. Until recently, routine oral vaccination for AdV serotypes 4 and 7 eliminated epidemic AdV-associated ARD in this population. Now that the manufacturer has ceased production, vaccination has ended and AdV epidemics have reappeared. As part of a prospective epidemiological study during the high-risk ARD season, serial samples were obtained from ventilation system filters and tested for AdV by culture and PCR. An outbreak occurred during this surveillance. Of 59 air filters, 26 (44%) were AdV positive only by PCR. Sequence analysis confirmed the presence of AdV serotype 4, the implicated outbreak serotype. The number of AdV-related hospitalizations was directly correlated with the proportion of filters containing AdV; correlation coefficients were 0.86 (Pearson) and 0.90 (Spearman's rho). This is the first report describing a PCR method to detect airborne AdV during an ARD outbreak. It suggests that this technique can detect and quantify AdV-associated ARD exposure and may enable further definition of environmental effects on AdV-associated ARD spread.

Adenovirus Infections, Human↗