Lourdes Guerrero - Academia.edu (original) (raw)

Papers by Lourdes Guerrero

Research paper thumbnail of Impact of formal training in endoscopic submucosal dissection for early gastrointestinal cancer: A systematic review and a meta-analysis

World journal of gastrointestinal endoscopy, Jan 16, 2015

To summarize the clinical impact of a formal training for the effectiveness and safety of endosco... more To summarize the clinical impact of a formal training for the effectiveness and safety of endoscopic submucosal dissection for gastrointestinal cancer. We searched databases including PubMed, EMBASE and the Cochrane Library and Science citation Index updated to August 2014 to include eligible articles. In the Meta-analysis, the main outcome measurements were en bloc resection rate, local recurrence rate (R0) and the incidence of procedure-related complications (perforation, bleeding). En bloc resection was high for both, dissecting stomach tumors with an overall percentage of 93.2% (95%CI: 90.5-95.8) and dissecting colorectal tumors with an overall percentage of 89.4% (95%CI: 85.1-93.7). Although the number of studies reporting R0 resection (the dissected specimen was revealed free of tumor in both vertical and lateral margins) was small, the overall estimates for R0 resection were 81.4% (95%CI: 72-90.8) for stomach and 85.9% (95%CI: 77.5-95.5) for colorectal tumors, respectively. T...

Research paper thumbnail of Protection against infection with Giardia lamblia by breast-feeding in a cohort of Mexican infants

To determine whether breast-feeding protects infants against symptomatic and asymptomatic infecti... more To determine whether breast-feeding protects infants against symptomatic and asymptomatic infection by Giardia lamblia, we followed 197 infants in a poor area of Mexico City from birth to 18 months of age; symptoms and feeding status were recorded weekly. Stool specimens were collected every 1 to 2 weeks and tested for Giardia by enzyme-linked immunosorbent assay. A mean of 1.0 Giardia infection per child-year was detected; 94 infants had a total of 139 infections; 17% of infections were symptomatic. Ninety-one percent of infants were breast fed from birth and 38% were breast fed at 1 year of age. Lack of breast-feeding was a significant risk factor for first Giardia infection at all ages. The adjusted incidence rate ratio for first Giardia infection for none versus complete breast-feeding was 5.0 (confidence interval (CI) 1.5 to 16.9; p = 0.009), and for none versus any breast-feeding, 1.8 (CI 1.1 to 2.8; p = 0.013). Symptomatic Giardia infection was also associated with lack of breast-feeding (none vs any: incidence rate ratio = 2.5; CI 0.9 to 6.8; p = 0.077), but breast-feeding did not protect against chronic carriage of Giardia. Other significant risk factors for Giardia infection were presence of animals in the household (p = 0.005) and the use of water or nonmilk liquid for infant feedings (p = 0.035). We conclude that breast-feeding protects infants against Giardia by mechanisms that include preventing the establishment of infection.

Research paper thumbnail of Immunogenicity and safety of a booster dose of the 10-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine coadministered with the tetravalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine in toddlers: a randomized trial

The Pediatric infectious disease journal, 2013

This open, randomized clinical trial (NCT00758264) evaluated the coadministration of a booster do... more This open, randomized clinical trial (NCT00758264) evaluated the coadministration of a booster dose of the 10-valent pneumococcal conjugate vaccine (PHiD-CV) and a single dose of the tetravalent meningococcal conjugate vaccine (MenACWY-TT) in Taiwanese and Mexican toddlers. Healthy toddlers aged 12-23 months (N = 363) were randomized (2:1:1) to receive either both vaccines at first visit, MenACWY-TT at first visit and 1 month later PHiD-CV, or PHiD-CV at first visit and 1 month later MenACWY-TT. Immune responses were measured 1 month after MenACWY-TT vaccination by meningococcal serum bactericidal activity (rSBA) assay and 1 month after PHiD-CV vaccination by pneumococcal 22F-inhibition enzyme-linked immunosorbent assay and functional opsonophagocytic activity assay. Solicited and unsolicited symptoms were recorded for days 4 and 31 postvaccination, respectively. Serious adverse events were recorded throughout the study. The prespecified criteria for noninferiority of coadministrati...

Research paper thumbnail of Duration of Exclusive Breastfeeding and Risk of Anemia in a Cohort of Mexican Infants

Advances in Experimental Medicine and Biology, 2004

DURATION OF EXCLUSIVE BREASTFEEDING AND RISK OF ANEMIA IN A COHORT OF MEXICAN INFANTS Jareen K. M... more DURATION OF EXCLUSIVE BREASTFEEDING AND RISK OF ANEMIA IN A COHORT OF MEXICAN INFANTS Jareen K. Meinzen-Derr1, M. Lourdes Guerrero, Mekibib Altaye1, Guillermo M. Ruiz-Palacios2, and Ardythe L. Morrow1 1. INTRODUCTION Iron deficiency is the most ...

Research paper thumbnail of Efficacy of home-based peer counselling to promote exclusive breastfeeding: a randomised controlled trial

Research paper thumbnail of Composition of pigments and colour changes in green table olives related to processing type

Food Chemistry, 2015

Brownish colourations in Natural green table olives (non-treated with alkali) make this 21 produc... more Brownish colourations in Natural green table olives (non-treated with alkali) make this 21 product less attractive to consumers than alkali), which develop a more appreciated bright golden-yellow colour. These colour 23 differences were studied in relation to changes in the composition of chlorophyll and 24 carotenoid pigments, as well as polyphenolic compounds and polyphenol oxidase 25 enzyme (PPO) activity. Natural green olives showed a different chlorophyll profile than 26 Spanish-style. However, all the chlorophyll pigments formed in both processing types 27

Research paper thumbnail of Human Milk α1,2-Linked Fucosylated Oligosaccharides Decrease Risk of Diarrhea Due to Stable Toxin of E. Coli in Breastfed Infants

Advances in Experimental Medicine and Biology, 2004

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Research paper thumbnail of Feeding of a Probiotic for the Prevention of Community-Acquired Diarrhea in Young Mexican Children. † 1089

Research paper thumbnail of Cohort study of rotavirus serotype patterns in symptomatic and asymptomatic infections in Mexican children

The Pediatric Infectious Disease Journal, 1993

A cohort of 200 Mexican children from a low income periurban community was monitored from birth t... more A cohort of 200 Mexican children from a low income periurban community was monitored from birth to the age of 2 years to determine the serotype-specific incidence, morbidity and seasonal pattern of symptomatic and asymptomatic human rotavirus (HRV) infections. A total of 177 HRV infections occurred in 134 (67%) children; 50% of these infections were asymptomatic. The incidence of all HRV infections was 0.6 episode/child year and was inversely related to age (r = -0.93; P < 0.01). The incidence of HRV-associated diarrhea was 0.3 episode/child year, with the highest frequency and severity occurring in infants between 4 and 6 months of age. HRV infections were more frequent each autumn, with a changing sequential pattern of predominant serotypes. Overall serotype 3 (34%) was the most frequent, followed by serotypes 1 (16%), 2 (15%) and 4 (6%). The 4 serotypes were associated with a similar risk for diarrhea and severity of diarrhea. In 23 (26%) HRV diarrhea-associated infections, an additional enteropathogen was identified; these mixed infections were more frequent in older children (chi square, 4.45; P < 0.05) but were not more severe (chi square, 0.02; P > 0.05). Our data indicate that HRV infections were common early in life, seasonal, frequently asymptomatic and caused by a variety of serotypes, none of which was a risk factor for diarrhea or severity of diarrhea.

Research paper thumbnail of Asymptomatic Shigella infections in a cohort of Mexican children younger than two years of age

The Pediatric Infectious Disease Journal, 1994

The proportion of Shigella infections that occur asymptomatically in young children has not been ... more The proportion of Shigella infections that occur asymptomatically in young children has not been established. A community-based cohort study of 367 infants was followed prospectively by weekly home visits from January, 1990, through December, 1991. Stool samples were collected weekly and when diarrhea occurred and were tested for Shigella and other enteropathogens. There were 2925 child months of observation and 65 episodes of Shigella infection. There were 3.1 episodes/100 child months during the warm season (May through September) and 0.97 episode/100 child months during the cold season. Shigella infections were rare during the first 6 months of life but increased with age (P < 0.0001). Overall 55% of detected infections were asymptomatic. The proportion of infections that were asymptomatic increased as age increased (P < 0.01). Symptom status was not significantly associated with Shigella species or season. All isolates from symptomatic and asymptomatic children had the 120- to 140-megadalton virulence plasmid. We conclude that infections with virulent strains of Shigella are commonly asymptomatic in Mexican children during the first 2 years of life.

Research paper thumbnail of Safety and Efficacy of an Attenuated Vaccine against Severe Rotavirus Gastroenteritis

New England Journal of Medicine, 2006

The safety and efficacy of an attenuated G1P[8] human rotavirus (HRV) vaccine were tested in a ra... more The safety and efficacy of an attenuated G1P[8] human rotavirus (HRV) vaccine were tested in a randomized, double-blind, phase 3 trial.

Research paper thumbnail of Protection against infection with Giardia lamblia by breast-feeding in a cohort of Mexican infants

The Journal of Pediatrics, 1992

To determine whether breast-feeding protects infants against symptomatic and asymptomatic infecti... more To determine whether breast-feeding protects infants against symptomatic and asymptomatic infection by Giardia lamblia, we followed 197 infants in a poor area of Mexico City from birth to 18 months of age; symptoms and feeding status were recorded weekly. Stool specimens were collected every 1 to 2 weeks and tested for Giardia by enzyme-linked immunosorbent assay. A mean of 1.0 Giardia infection per child-year was detected; 94 infants had a total of 139 infections; 17% of infections were symptomatic. Ninety-one percent of infants were breast fed from birth and 38% were breast fed at 1 year of age. Lack of breast-feeding was a significant risk factor for first Giardia infection at all ages. The adjusted incidence rate ratio for first Giardia infection for none versus complete breast-feeding was 5.0 (confidence interval (CI) 1.5 to 16.9; p = 0.009), and for none versus any breast-feeding, 1.8 (CI 1.1 to 2.8; p = 0.013). Symptomatic Giardia infection was also associated with lack of breast-feeding (none vs any: incidence rate ratio = 2.5; CI 0.9 to 6.8; p = 0.077), but breast-feeding did not protect against chronic carriage of Giardia. Other significant risk factors for Giardia infection were presence of animals in the household (p = 0.005) and the use of water or nonmilk liquid for infant feedings (p = 0.035). We conclude that breast-feeding protects infants against Giardia by mechanisms that include preventing the establishment of infection.

Research paper thumbnail of Human milk oligosaccharides are associated with protection against diarrhea in breast-fed infants

The Journal of Pediatrics, 2004

To determine the association between maternal milk levels of 2-linked fucosylated oligosaccharide... more To determine the association between maternal milk levels of 2-linked fucosylated oligosaccharide and prevention of diarrhea as a result of Campylobacter, caliciviruses, and diarrhea of all causes in breast-fed infants. Data and banked samples were analyzed from 93 breast-feeding mother-infant pairs who were prospectively studied during 1988-1991 from birth to 2 years with infant feeding and diarrhea data collected weekly; diarrhea was diagnosed by a study physician. Milk samples obtained 1 to 5 weeks postpartum were analyzed for oligosaccharide content. Data were analyzed by Poisson regression. Total 2-linked fucosyloligosaccharide in maternal milk ranged from 0.8 to 20.8 mmol/L (50%-92% of milk oligosaccharide). Moderate-to-severe diarrhea of all causes (n=77 cases) occurred less often (P=.001) in infants whose milk contained high levels of total 2-linked fucosyloligosaccharide as a percent of milk oligosaccharide. Campylobacter diarrhea (n=31 cases) occurred less often (P=.004) in infants whose mother's milk contained high levels of 2'-FL, a specific 2-linked fucosyloligosaccharide, and calicivirus diarrhea (n=16 cases) occurred less often (P=.012) in infants whose mother's milk contained high levels of lacto-N-difucohexaose (LDFH-I), another 2-linked fucosyloligosaccharide. This study provides novel evidence suggesting that human milk oligosaccharides are clinically relevant to protection against infant diarrhea.

Research paper thumbnail of Prevalence and genetic diversity of human caliciviruses (HuCVs) in Mexican children

Journal of Medical Virology, 2000

Human caliciviruses (HuCVs) contain two genera: "Norwalk-like viruses" (NLVs) and "Sapporo-like v... more Human caliciviruses (HuCVs) contain two genera: "Norwalk-like viruses" (NLVs) and "Sapporo-like viruses" (SLVs). The importance of the two genera as a cause of acute gastroenteritis of infants and children remains unknown. Beginning in 1989, a birth cohort of children in Mexico was enrolled and monitored for acute gastroenteritis. A subset of 115 diarrhea stool specimens from 76 children and 66 non-diarrhea stool specimens from 64 children was examined for HuCVs by RT-PCR by using a primer pair (p289/ 290) that detects both NLVs and SLVs. Twentytwo (19%) of the 115 diarrhea stool specimens and 5 (7%) of 66 non-diarrhea stool specimens produced RT-PCR products of expected size (319 bp for NLVs and 331 bp for SLVs). Twenty of the twenty-seven strains were cloned and sequenced. Pairwise sequence analysis showed that 9 (60%) and 6 (40%) of the 15 strains from the diarrhea stools were NLVs and SLVs, respectively. The same proportions of NLVs (60%) and SLVs (40%) were observed in the non-diarrhea stools. Strains in the NLV genus could be further divided into four clusters: Lordsdale, MxV, and HV and one potentially new cluster. Strains in the SLV genus could be divided into three clusters: Sapporo/82, Lon/92, and a potentially new cluster. Strains from the Lordsdale cluster were the most common among these children. The findings of both genera and multiple clusters of HuCVs co-circulating and the identification of new strains of HuCVs in the population justify the need for future studies of HuCVs in infants and children.

Research paper thumbnail of Serum Antibody as a Marker of Protection against Natural Rotavirus Infection and Disease

The Journal of Infectious Diseases, 2000

Research paper thumbnail of Molecular Epidemiology of Human Astrovirus Diarrhea among Children from a Periurban Community of Mexico City

The Journal of Infectious Diseases, 2001

Human astroviruses (HAstVs) were detected in 23 stool samples from 365 diarrhea episodes among 21... more Human astroviruses (HAstVs) were detected in 23 stool samples from 365 diarrhea episodes among 214 children (!18 months old) prospectively monitored for diarrhea in Mexico City. Stool samples were tested by EIA and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. EIA was less sensitive (74%) and equally specific, compared with RT-PCR analysis using type-common primers for HAstV detection. Of 31 HAstV isolates, EIA typed 18 (69%) of 26 EIA-positive samples, and RT-PCR analysis typed 26 (84%) of 31 RT-PCRpositive samples. Phylogenetic analysis of the 3 end of the capsid region (363 nucleotides) confirmed the type assignment by EIA and RT-PCR analysis and determined the type for 5 previously untyped samples. Six HAstV antigenic types cocirculated in the community: HAstV-2 (42%), HAstV-4 (23%), HAstV-3 (13%), HAstV-1 (10%), HAstV-5 (6%), and HAstV-7 (6%). RT-PCR and sequence analysis provided more detailed epidemiology of HAstV in the community than did antigenic detection methods.

Research paper thumbnail of Risk factors for repeated rotavirus infections in Mexican infants

Journal of Clinical Epidemiology, 1996

Research paper thumbnail of Pigment−Lipoprotein Complexes in Table Olives (Cv. Gordal) with Green Staining Alteration

Journal of Agricultural and Food Chemistry, 2003

In table olives showing the green staining alteration, extracts of pigment-lipoprotein complexes ... more In table olives showing the green staining alteration, extracts of pigment-lipoprotein complexes were obtained from the zone altered and the rest of the fruit. In the altered zone of the olive, the surrounding components of pigments were affected, with the degeneration of proteins and phospholipids forming the pigment-lipoprotein complexes. There was also less interaction between the pigments and the membrane lipids. These results suggested a greater loss of cell integrity in the green-stained zone of the fruit, allowing the migration and local accumulation of Cu-metallochlorophyll complexes, macroscopically visible as the form of green staining alteration.

Research paper thumbnail of Clinical characteristics and outcomes of influenza and other influenza-like illnesses in Mexico City

International Journal of Infectious Diseases, 2013

Background: Influenza-like illnesses (ILI) are estimated to cause millions of deaths annually. De... more Background: Influenza-like illnesses (ILI) are estimated to cause millions of deaths annually. Despite this disease burden, the etiologic causes of ILI are poorly described for many geographical regions. Methods: Beginning in April 2010, we conducted an observational cohort study at five hospitals in Mexico City, enrolling subjects who met the criteria for ILI. Evaluations were conducted at enrollment and on day 28, with the collection of clinical data and a nasopharyngeal swab (or nasal aspirate in children). Swabs were tested by multiplex PCR for 15 viral pathogens and real-time PCR for influenza. Results: During the first year, 1065 subjects were enrolled in this study, 55% of whom were hospitalized; 24% of all subjects were children. One or more pathogens were detected by PCR in 64% of subjects, most commonly rhinovirus (25% of all isolates) and influenza (24% of isolates). Six percent of subjects died, and of those, 54% had no pathogen identified. Rhinovirus was the most common pathogen among those who died, although it did not have the highest case fatality rate. Conclusions: Multiple respiratory viruses beyond influenza are associated with significant morbidity and mortality among adults and children in Mexico City. Detection of these agents could be useful for the adjustment of antibiotic treatment in severe cases. ß

Research paper thumbnail of Immunogenicity, reactogenicity and safety of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) in Mexican infants

Human Vaccines, 2011

The immunogenicity and safety of the 10-valent pneumococcal conjugate vaccine, PHiD-CV, have been... more The immunogenicity and safety of the 10-valent pneumococcal conjugate vaccine, PHiD-CV, have been documented in European and Asian studies. In this open study conducted in Mexico (NCT00489554), 230 healthy infants received three doses of PHiD-CV and DTPa-HBV-IPV/Hib vaccines at 2, 4 and 6 months of age and two doses of oral human rotavirus vaccine at 2 and 4 months. Serotype-specific pneumococcal responses and opsonophagocytic activity (OPA) were measured one month post-dose 3. PHiD-CV's primary vaccination course was highly immunogenic against each of the 10 pneumococcal vaccine serotypes and carrier protein D. Antibody responses against pneumococcal serotypes and protein D were generally higher in Mexican infants compared with European antibody responses, and functional OPA responses were also higher or in the same range. The most frequent solicited local symptom was pain, with high but similar incidences of grade 3 pain reported at both injection sites (up to 15% of all doses). PHiD-CV was well tolerated, with no serious adverse events considered as causally related to vaccination. Most solicited symptoms were mild and there was no increase in incidence of solicited symptoms with successive vaccine doses.

Research paper thumbnail of Impact of formal training in endoscopic submucosal dissection for early gastrointestinal cancer: A systematic review and a meta-analysis

World journal of gastrointestinal endoscopy, Jan 16, 2015

To summarize the clinical impact of a formal training for the effectiveness and safety of endosco... more To summarize the clinical impact of a formal training for the effectiveness and safety of endoscopic submucosal dissection for gastrointestinal cancer. We searched databases including PubMed, EMBASE and the Cochrane Library and Science citation Index updated to August 2014 to include eligible articles. In the Meta-analysis, the main outcome measurements were en bloc resection rate, local recurrence rate (R0) and the incidence of procedure-related complications (perforation, bleeding). En bloc resection was high for both, dissecting stomach tumors with an overall percentage of 93.2% (95%CI: 90.5-95.8) and dissecting colorectal tumors with an overall percentage of 89.4% (95%CI: 85.1-93.7). Although the number of studies reporting R0 resection (the dissected specimen was revealed free of tumor in both vertical and lateral margins) was small, the overall estimates for R0 resection were 81.4% (95%CI: 72-90.8) for stomach and 85.9% (95%CI: 77.5-95.5) for colorectal tumors, respectively. T...

Research paper thumbnail of Protection against infection with Giardia lamblia by breast-feeding in a cohort of Mexican infants

To determine whether breast-feeding protects infants against symptomatic and asymptomatic infecti... more To determine whether breast-feeding protects infants against symptomatic and asymptomatic infection by Giardia lamblia, we followed 197 infants in a poor area of Mexico City from birth to 18 months of age; symptoms and feeding status were recorded weekly. Stool specimens were collected every 1 to 2 weeks and tested for Giardia by enzyme-linked immunosorbent assay. A mean of 1.0 Giardia infection per child-year was detected; 94 infants had a total of 139 infections; 17% of infections were symptomatic. Ninety-one percent of infants were breast fed from birth and 38% were breast fed at 1 year of age. Lack of breast-feeding was a significant risk factor for first Giardia infection at all ages. The adjusted incidence rate ratio for first Giardia infection for none versus complete breast-feeding was 5.0 (confidence interval (CI) 1.5 to 16.9; p = 0.009), and for none versus any breast-feeding, 1.8 (CI 1.1 to 2.8; p = 0.013). Symptomatic Giardia infection was also associated with lack of breast-feeding (none vs any: incidence rate ratio = 2.5; CI 0.9 to 6.8; p = 0.077), but breast-feeding did not protect against chronic carriage of Giardia. Other significant risk factors for Giardia infection were presence of animals in the household (p = 0.005) and the use of water or nonmilk liquid for infant feedings (p = 0.035). We conclude that breast-feeding protects infants against Giardia by mechanisms that include preventing the establishment of infection.

Research paper thumbnail of Immunogenicity and safety of a booster dose of the 10-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine coadministered with the tetravalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine in toddlers: a randomized trial

The Pediatric infectious disease journal, 2013

This open, randomized clinical trial (NCT00758264) evaluated the coadministration of a booster do... more This open, randomized clinical trial (NCT00758264) evaluated the coadministration of a booster dose of the 10-valent pneumococcal conjugate vaccine (PHiD-CV) and a single dose of the tetravalent meningococcal conjugate vaccine (MenACWY-TT) in Taiwanese and Mexican toddlers. Healthy toddlers aged 12-23 months (N = 363) were randomized (2:1:1) to receive either both vaccines at first visit, MenACWY-TT at first visit and 1 month later PHiD-CV, or PHiD-CV at first visit and 1 month later MenACWY-TT. Immune responses were measured 1 month after MenACWY-TT vaccination by meningococcal serum bactericidal activity (rSBA) assay and 1 month after PHiD-CV vaccination by pneumococcal 22F-inhibition enzyme-linked immunosorbent assay and functional opsonophagocytic activity assay. Solicited and unsolicited symptoms were recorded for days 4 and 31 postvaccination, respectively. Serious adverse events were recorded throughout the study. The prespecified criteria for noninferiority of coadministrati...

Research paper thumbnail of Duration of Exclusive Breastfeeding and Risk of Anemia in a Cohort of Mexican Infants

Advances in Experimental Medicine and Biology, 2004

DURATION OF EXCLUSIVE BREASTFEEDING AND RISK OF ANEMIA IN A COHORT OF MEXICAN INFANTS Jareen K. M... more DURATION OF EXCLUSIVE BREASTFEEDING AND RISK OF ANEMIA IN A COHORT OF MEXICAN INFANTS Jareen K. Meinzen-Derr1, M. Lourdes Guerrero, Mekibib Altaye1, Guillermo M. Ruiz-Palacios2, and Ardythe L. Morrow1 1. INTRODUCTION Iron deficiency is the most ...

Research paper thumbnail of Efficacy of home-based peer counselling to promote exclusive breastfeeding: a randomised controlled trial

Research paper thumbnail of Composition of pigments and colour changes in green table olives related to processing type

Food Chemistry, 2015

Brownish colourations in Natural green table olives (non-treated with alkali) make this 21 produc... more Brownish colourations in Natural green table olives (non-treated with alkali) make this 21 product less attractive to consumers than alkali), which develop a more appreciated bright golden-yellow colour. These colour 23 differences were studied in relation to changes in the composition of chlorophyll and 24 carotenoid pigments, as well as polyphenolic compounds and polyphenol oxidase 25 enzyme (PPO) activity. Natural green olives showed a different chlorophyll profile than 26 Spanish-style. However, all the chlorophyll pigments formed in both processing types 27

Research paper thumbnail of Human Milk α1,2-Linked Fucosylated Oligosaccharides Decrease Risk of Diarrhea Due to Stable Toxin of E. Coli in Breastfed Infants

Advances in Experimental Medicine and Biology, 2004

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Research paper thumbnail of Feeding of a Probiotic for the Prevention of Community-Acquired Diarrhea in Young Mexican Children. † 1089

Research paper thumbnail of Cohort study of rotavirus serotype patterns in symptomatic and asymptomatic infections in Mexican children

The Pediatric Infectious Disease Journal, 1993

A cohort of 200 Mexican children from a low income periurban community was monitored from birth t... more A cohort of 200 Mexican children from a low income periurban community was monitored from birth to the age of 2 years to determine the serotype-specific incidence, morbidity and seasonal pattern of symptomatic and asymptomatic human rotavirus (HRV) infections. A total of 177 HRV infections occurred in 134 (67%) children; 50% of these infections were asymptomatic. The incidence of all HRV infections was 0.6 episode/child year and was inversely related to age (r = -0.93; P < 0.01). The incidence of HRV-associated diarrhea was 0.3 episode/child year, with the highest frequency and severity occurring in infants between 4 and 6 months of age. HRV infections were more frequent each autumn, with a changing sequential pattern of predominant serotypes. Overall serotype 3 (34%) was the most frequent, followed by serotypes 1 (16%), 2 (15%) and 4 (6%). The 4 serotypes were associated with a similar risk for diarrhea and severity of diarrhea. In 23 (26%) HRV diarrhea-associated infections, an additional enteropathogen was identified; these mixed infections were more frequent in older children (chi square, 4.45; P < 0.05) but were not more severe (chi square, 0.02; P > 0.05). Our data indicate that HRV infections were common early in life, seasonal, frequently asymptomatic and caused by a variety of serotypes, none of which was a risk factor for diarrhea or severity of diarrhea.

Research paper thumbnail of Asymptomatic Shigella infections in a cohort of Mexican children younger than two years of age

The Pediatric Infectious Disease Journal, 1994

The proportion of Shigella infections that occur asymptomatically in young children has not been ... more The proportion of Shigella infections that occur asymptomatically in young children has not been established. A community-based cohort study of 367 infants was followed prospectively by weekly home visits from January, 1990, through December, 1991. Stool samples were collected weekly and when diarrhea occurred and were tested for Shigella and other enteropathogens. There were 2925 child months of observation and 65 episodes of Shigella infection. There were 3.1 episodes/100 child months during the warm season (May through September) and 0.97 episode/100 child months during the cold season. Shigella infections were rare during the first 6 months of life but increased with age (P < 0.0001). Overall 55% of detected infections were asymptomatic. The proportion of infections that were asymptomatic increased as age increased (P < 0.01). Symptom status was not significantly associated with Shigella species or season. All isolates from symptomatic and asymptomatic children had the 120- to 140-megadalton virulence plasmid. We conclude that infections with virulent strains of Shigella are commonly asymptomatic in Mexican children during the first 2 years of life.

Research paper thumbnail of Safety and Efficacy of an Attenuated Vaccine against Severe Rotavirus Gastroenteritis

New England Journal of Medicine, 2006

The safety and efficacy of an attenuated G1P[8] human rotavirus (HRV) vaccine were tested in a ra... more The safety and efficacy of an attenuated G1P[8] human rotavirus (HRV) vaccine were tested in a randomized, double-blind, phase 3 trial.

Research paper thumbnail of Protection against infection with Giardia lamblia by breast-feeding in a cohort of Mexican infants

The Journal of Pediatrics, 1992

To determine whether breast-feeding protects infants against symptomatic and asymptomatic infecti... more To determine whether breast-feeding protects infants against symptomatic and asymptomatic infection by Giardia lamblia, we followed 197 infants in a poor area of Mexico City from birth to 18 months of age; symptoms and feeding status were recorded weekly. Stool specimens were collected every 1 to 2 weeks and tested for Giardia by enzyme-linked immunosorbent assay. A mean of 1.0 Giardia infection per child-year was detected; 94 infants had a total of 139 infections; 17% of infections were symptomatic. Ninety-one percent of infants were breast fed from birth and 38% were breast fed at 1 year of age. Lack of breast-feeding was a significant risk factor for first Giardia infection at all ages. The adjusted incidence rate ratio for first Giardia infection for none versus complete breast-feeding was 5.0 (confidence interval (CI) 1.5 to 16.9; p = 0.009), and for none versus any breast-feeding, 1.8 (CI 1.1 to 2.8; p = 0.013). Symptomatic Giardia infection was also associated with lack of breast-feeding (none vs any: incidence rate ratio = 2.5; CI 0.9 to 6.8; p = 0.077), but breast-feeding did not protect against chronic carriage of Giardia. Other significant risk factors for Giardia infection were presence of animals in the household (p = 0.005) and the use of water or nonmilk liquid for infant feedings (p = 0.035). We conclude that breast-feeding protects infants against Giardia by mechanisms that include preventing the establishment of infection.

Research paper thumbnail of Human milk oligosaccharides are associated with protection against diarrhea in breast-fed infants

The Journal of Pediatrics, 2004

To determine the association between maternal milk levels of 2-linked fucosylated oligosaccharide... more To determine the association between maternal milk levels of 2-linked fucosylated oligosaccharide and prevention of diarrhea as a result of Campylobacter, caliciviruses, and diarrhea of all causes in breast-fed infants. Data and banked samples were analyzed from 93 breast-feeding mother-infant pairs who were prospectively studied during 1988-1991 from birth to 2 years with infant feeding and diarrhea data collected weekly; diarrhea was diagnosed by a study physician. Milk samples obtained 1 to 5 weeks postpartum were analyzed for oligosaccharide content. Data were analyzed by Poisson regression. Total 2-linked fucosyloligosaccharide in maternal milk ranged from 0.8 to 20.8 mmol/L (50%-92% of milk oligosaccharide). Moderate-to-severe diarrhea of all causes (n=77 cases) occurred less often (P=.001) in infants whose milk contained high levels of total 2-linked fucosyloligosaccharide as a percent of milk oligosaccharide. Campylobacter diarrhea (n=31 cases) occurred less often (P=.004) in infants whose mother's milk contained high levels of 2'-FL, a specific 2-linked fucosyloligosaccharide, and calicivirus diarrhea (n=16 cases) occurred less often (P=.012) in infants whose mother's milk contained high levels of lacto-N-difucohexaose (LDFH-I), another 2-linked fucosyloligosaccharide. This study provides novel evidence suggesting that human milk oligosaccharides are clinically relevant to protection against infant diarrhea.

Research paper thumbnail of Prevalence and genetic diversity of human caliciviruses (HuCVs) in Mexican children

Journal of Medical Virology, 2000

Human caliciviruses (HuCVs) contain two genera: "Norwalk-like viruses" (NLVs) and "Sapporo-like v... more Human caliciviruses (HuCVs) contain two genera: "Norwalk-like viruses" (NLVs) and "Sapporo-like viruses" (SLVs). The importance of the two genera as a cause of acute gastroenteritis of infants and children remains unknown. Beginning in 1989, a birth cohort of children in Mexico was enrolled and monitored for acute gastroenteritis. A subset of 115 diarrhea stool specimens from 76 children and 66 non-diarrhea stool specimens from 64 children was examined for HuCVs by RT-PCR by using a primer pair (p289/ 290) that detects both NLVs and SLVs. Twentytwo (19%) of the 115 diarrhea stool specimens and 5 (7%) of 66 non-diarrhea stool specimens produced RT-PCR products of expected size (319 bp for NLVs and 331 bp for SLVs). Twenty of the twenty-seven strains were cloned and sequenced. Pairwise sequence analysis showed that 9 (60%) and 6 (40%) of the 15 strains from the diarrhea stools were NLVs and SLVs, respectively. The same proportions of NLVs (60%) and SLVs (40%) were observed in the non-diarrhea stools. Strains in the NLV genus could be further divided into four clusters: Lordsdale, MxV, and HV and one potentially new cluster. Strains in the SLV genus could be divided into three clusters: Sapporo/82, Lon/92, and a potentially new cluster. Strains from the Lordsdale cluster were the most common among these children. The findings of both genera and multiple clusters of HuCVs co-circulating and the identification of new strains of HuCVs in the population justify the need for future studies of HuCVs in infants and children.

Research paper thumbnail of Serum Antibody as a Marker of Protection against Natural Rotavirus Infection and Disease

The Journal of Infectious Diseases, 2000

Research paper thumbnail of Molecular Epidemiology of Human Astrovirus Diarrhea among Children from a Periurban Community of Mexico City

The Journal of Infectious Diseases, 2001

Human astroviruses (HAstVs) were detected in 23 stool samples from 365 diarrhea episodes among 21... more Human astroviruses (HAstVs) were detected in 23 stool samples from 365 diarrhea episodes among 214 children (!18 months old) prospectively monitored for diarrhea in Mexico City. Stool samples were tested by EIA and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. EIA was less sensitive (74%) and equally specific, compared with RT-PCR analysis using type-common primers for HAstV detection. Of 31 HAstV isolates, EIA typed 18 (69%) of 26 EIA-positive samples, and RT-PCR analysis typed 26 (84%) of 31 RT-PCRpositive samples. Phylogenetic analysis of the 3 end of the capsid region (363 nucleotides) confirmed the type assignment by EIA and RT-PCR analysis and determined the type for 5 previously untyped samples. Six HAstV antigenic types cocirculated in the community: HAstV-2 (42%), HAstV-4 (23%), HAstV-3 (13%), HAstV-1 (10%), HAstV-5 (6%), and HAstV-7 (6%). RT-PCR and sequence analysis provided more detailed epidemiology of HAstV in the community than did antigenic detection methods.

Research paper thumbnail of Risk factors for repeated rotavirus infections in Mexican infants

Journal of Clinical Epidemiology, 1996

Research paper thumbnail of Pigment−Lipoprotein Complexes in Table Olives (Cv. Gordal) with Green Staining Alteration

Journal of Agricultural and Food Chemistry, 2003

In table olives showing the green staining alteration, extracts of pigment-lipoprotein complexes ... more In table olives showing the green staining alteration, extracts of pigment-lipoprotein complexes were obtained from the zone altered and the rest of the fruit. In the altered zone of the olive, the surrounding components of pigments were affected, with the degeneration of proteins and phospholipids forming the pigment-lipoprotein complexes. There was also less interaction between the pigments and the membrane lipids. These results suggested a greater loss of cell integrity in the green-stained zone of the fruit, allowing the migration and local accumulation of Cu-metallochlorophyll complexes, macroscopically visible as the form of green staining alteration.

Research paper thumbnail of Clinical characteristics and outcomes of influenza and other influenza-like illnesses in Mexico City

International Journal of Infectious Diseases, 2013

Background: Influenza-like illnesses (ILI) are estimated to cause millions of deaths annually. De... more Background: Influenza-like illnesses (ILI) are estimated to cause millions of deaths annually. Despite this disease burden, the etiologic causes of ILI are poorly described for many geographical regions. Methods: Beginning in April 2010, we conducted an observational cohort study at five hospitals in Mexico City, enrolling subjects who met the criteria for ILI. Evaluations were conducted at enrollment and on day 28, with the collection of clinical data and a nasopharyngeal swab (or nasal aspirate in children). Swabs were tested by multiplex PCR for 15 viral pathogens and real-time PCR for influenza. Results: During the first year, 1065 subjects were enrolled in this study, 55% of whom were hospitalized; 24% of all subjects were children. One or more pathogens were detected by PCR in 64% of subjects, most commonly rhinovirus (25% of all isolates) and influenza (24% of isolates). Six percent of subjects died, and of those, 54% had no pathogen identified. Rhinovirus was the most common pathogen among those who died, although it did not have the highest case fatality rate. Conclusions: Multiple respiratory viruses beyond influenza are associated with significant morbidity and mortality among adults and children in Mexico City. Detection of these agents could be useful for the adjustment of antibiotic treatment in severe cases. ß

Research paper thumbnail of Immunogenicity, reactogenicity and safety of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) in Mexican infants

Human Vaccines, 2011

The immunogenicity and safety of the 10-valent pneumococcal conjugate vaccine, PHiD-CV, have been... more The immunogenicity and safety of the 10-valent pneumococcal conjugate vaccine, PHiD-CV, have been documented in European and Asian studies. In this open study conducted in Mexico (NCT00489554), 230 healthy infants received three doses of PHiD-CV and DTPa-HBV-IPV/Hib vaccines at 2, 4 and 6 months of age and two doses of oral human rotavirus vaccine at 2 and 4 months. Serotype-specific pneumococcal responses and opsonophagocytic activity (OPA) were measured one month post-dose 3. PHiD-CV's primary vaccination course was highly immunogenic against each of the 10 pneumococcal vaccine serotypes and carrier protein D. Antibody responses against pneumococcal serotypes and protein D were generally higher in Mexican infants compared with European antibody responses, and functional OPA responses were also higher or in the same range. The most frequent solicited local symptom was pain, with high but similar incidences of grade 3 pain reported at both injection sites (up to 15% of all doses). PHiD-CV was well tolerated, with no serious adverse events considered as causally related to vaccination. Most solicited symptoms were mild and there was no increase in incidence of solicited symptoms with successive vaccine doses.