Laura Mendoza - Academia.edu (original) (raw)

Papers by Laura Mendoza

World Allergy Organization Journal, 2012

ABSTRACT

Microbial Ecol, 2006

The diterpenoid kaurenoic acid is the main component of the resin from the medicinal plant Pseudo... more The diterpenoid kaurenoic acid is the main component of the resin from the medicinal plant Pseudognaphalium vira vira. As some diterpenoids have antimicrobial properties, the effect of this resin and the kaurenoic acid on soil bacteria was studied. The resin of P. vira vira and purified kaurenoic acid were two to four times more effective as antibacterial agents with Gram-positive than with Gram-negative soil isolates. The chemical stability of kaurenoic acid and the antibacterial activity of both the resin and the diterpenoid were studied in microcosms containing plant-associated soil. After 15 days of incubation, the diterpenoid was stable, as determined by 1 H nuclear magnetic resonance and thin-layer chromatography, and soil extracts still exhibited antibacterial activity. However, after 30 days of incubation, loss of antibacterial activity of soil extracts correlated with removal or chemical modification of kaurenoic acid. The effect of the resin or this diterpenoid on the soil bacteria community was analyzed by the terminal restriction fragment length polymorphisms technique. After 15 days of incubation, the resin and the pure compound caused significant changes in the soil bacterial community. The relative abundance of specific bacterial groups was differentially affected by the resin components, being the effects with the resin stronger than with the kaurenoic acid. After 30 days of incubation, these changes mostly reverted. These results indicate that a plant resin containing diterpenoid compounds plays a significant role controlling specific groups of microorganisms in the soil associated with the plant.

Analytical Biochemistry, Apr 15, 2008

In the present study, we propose a general and accessible method for the resolution of enantiomer... more In the present study, we propose a general and accessible method for the resolution of enantiomeric 1,2-sn-and 2,3-sn-diacylglycerols based on derivatization by isocyanates, which can be easily used routinely by biochemists to evaluate the stereopreferences of lipases in a time course of triacylglycerol (TAG) hydrolysis. Diacylglycerol (DAG) enantiomers were transformed into carbamates using achiral and commercially available reagents. Excellent separation and resolution factors were obtained for diacylglycerols present in lipolysis reaction mixtures. This analytical method was then applied to investigate the stereoselectivity of three model lipases (porcine pancreatic lipase, PPL; lipase from Rhizomucor miehei, MML; and recombinant dog gastric lipase, rDGL) in the time course of hydrolysis of prochiral triolein as a substrate. From the measurements of the diglyceride enantiomeric excess it was confirmed that PPL was not stereospecific (position sn-1 vs sn-3 of triolein), whereas MML and rDGL preferentially hydrolyzed the ester bond at position sn-1 and sn-3, respectively. The enantiomeric excess of DAGs was not constant with time, decreasing with the course of hydrolysis. This was due to the fact that DAGs can be products of the stereospecific hydrolysis of TAGs and substrates for stereospecific hydrolysis into monoacylglycerols.

Talanta, 2015

A Gas Chromatography (GC) method has been developed for the separation and characterization of th... more A Gas Chromatography (GC) method has been developed for the separation and characterization of the different fatty acids in anhydrous milk fat (AMF) by means of an ionic liquid stationary phase, characterized by a monocationic imidazolium salt derived from l-phenylalanine. The inner surface of a fused silica capillary column was modified using this ionic liquid functionality and 3-aminopropyldiethoxymethyl silane. This coated GC column, which exhibited good thermal stability (270°C) and good efficiency (2700 plates/m), has been characterized using the Abraham solvation parameter model. The intra-day and inter-day precision of the method have been evaluated, obtaining relative standard deviations (RSD) from 0.99% to 4.0% and from 2.8% to 9.2%, respectively. Furthermore, recoveries from 90% and 99% have been achieved.

Phytochemistry, 1999

From the resinous exudate of Haplopappus deserticola a new clerodane diterpene named deserticolic... more From the resinous exudate of Haplopappus deserticola a new clerodane diterpene named deserticolic acid (1), the known 18acetoxy-cis-cleroda-3,13E-dien-15-oic acid (2) and four¯avonoids were isolated. The structure of 1 was elucidated as 19hydroxy-cis-cleroda-3,13E-dien-15-oic acid (ent-5a form) by spectroscopic methods. #

Revista chilena de enfermedades respiratorias, 2011

Education is considered a core component of pulmonary rehabilitation. Rather than to simply provi... more Education is considered a core component of pulmonary rehabilitation. Rather than to simply provide didactic education, the recommendation now is to promote self-effi cacy through teaching self-management skills (quality evidence B, moderate recommendation). The main components of self-management education are the use of action plan for early treatment of exacerbations, breathing strategies and bronchial hygiene techniques and the adherence to exercise at home. There still need of evidence about which mechanisms of self-management education have the most perdurable effects.

Hexagon Series on Human and Environmental Security and Peace, 2011

Lack of potable water is an important problem of global dimensions. In Mexico, the northern and c... more Lack of potable water is an important problem of global dimensions. In Mexico, the northern and central regions have significant shortages, a situation which is exacerbated by the pollution of aquifers. Several studies have reported controversial results on high concentrations of heavy metals and halogens in aquifers in the state of Aguascalientes. Poor water quality is caused by the geological conditions in the region, water over-exploitation, and inadequate disposal of industrial waste. However, human exposure to these xenobiotics and their associated toxicological impact has received minimal attention. Many of these contaminants are nephrotoxic agents and this condition is aggravated when they mix.

Physiological and molecular plant pathology, 2008

AvrRxv is a member of a family of pathogen effectors present in pathogens of both plant and mamma... more AvrRxv is a member of a family of pathogen effectors present in pathogens of both plant and mammalian species. Xanthomonas campestris pv. vesicatoria strains carrying AvrRxv induce a hypersensitive response (HR) in the tomato cultivar Hawaii 7998. Using a yeast two-hybrid screen, we identified a 14-3-3 protein from tomato that interacts with AvrRxv called AvrRxv Interactor 1 (ARI1). The interaction was confirmed in vitro with affinity chromatography. Using mutagenesis, we identified a 14-3-3-binding domain in AvrRxv and demonstrated that a mutant in that domain showed concomitant loss of interaction with ARI1 and HR-inducing activity in tomato. These results demonstrate that the AvrRxv bacterial effector recruits 14-3-3 proteins for its function within host cells. AvrRxv homologues YopP and YopJ from Yersinia do not have AvrRxv-specific HR-inducing activity when delivered into tomato host cells by Agrobacterium. Although YopP itself cannot induce HR, its C-terminal domain containing...

Respirology, 2014

Quadriceps muscle dysfunction is an important contributor to exercise limitation in chronic obstr... more Quadriceps muscle dysfunction is an important contributor to exercise limitation in chronic obstructive pulmonary disease, but little is known about skeletal muscle function and its impact on exercise capacity in patients with fibrotic idiopathic interstitial pneumonia (IIP). The aim of the study was to compare quadriceps strength and endurance in patients with fibrotic IIP and healthy controls, and relate it to exercise capacity. Quadriceps strength and endurance, as well as respiratory muscle strength, and 6-min walk distance were compared among 25 patients with fibrotic IIP, forced vital capacity mean (standard deviation) 78.7 (14.0) %predicted, carbon monoxide transfer factor 40.3 (10.9) %predicted and 33 age-matched healthy controls using non-volitional measures. Quadriceps strength was assessed using magnetic femoral nerve stimulation (quadriceps twitch force), and endurance using the decay in force in response to repetitive magnetic stimulation of the quadriceps over 5 min. Both groups had comparable anthropometrics, gender proportion and respiratory muscle strength. Patients were significantly weaker than controls; quadriceps twitch force 10.1 (3.0) kg versus 8.0 (2.4) kg (P = 0.013). Quadriceps force in response to repetitive magnetic stimulation declined significantly more rapidly in patients during the endurance protocol (P < 0.001). In controls, there was a significant relationship between 6-min walk distance and quadriceps twitch force (r 0.40, P = 0.038), and quadriceps endurance (r 0.59, P = 0.016). In patients, only PaO2 and inspiratory muscle strength were retained as independent correlates of 6-min walk distance (r(2) = 0.3 P = 0.022). Quadriceps strength and endurance are reduced in patients with fibrotic IIP compared with healthy controls, but are less tightly correlated with exercise performance.

PLoS ONE, 2013

Our aim was to compare the longitudinal lung function growth of Mexican children and adolescents ... more Our aim was to compare the longitudinal lung function growth of Mexican children and adolescents with the collated spirometric reference proposed for international use and with that of Mexican-Americans from the National Health State Examination Survey III (NHANES) III study.

Pediatric Pulmonology, 2003

We set out to describe the pattern of lung function growth in Mexican students from 8-20 years of... more We set out to describe the pattern of lung function growth in Mexican students from 8-20 years of age, using internationally accepted equipment and methodology, and to compare it to values reported for Mexican-American children. Out of a total of 6,803 students from primary school to high school studied cross-sectionally in the Mexico City metropolitan area, we selected 4,009 asymptomatic, nonobese, nonsmoker subjects to generate spirometric prediction equations. We describe regression equations for the main spirometric variables (log transformed) based on age, height, and weight, and separated for males and females. Spirometric function in the population studied was above that predicted for European (Quanjer et al. [1987] Pediatr Pulmonol 19:135-142) or Mexican-American children, for the same age, height, and gender. On average, forced expiratory volume in 1 sec (FEV(1)) in Mexican children was 9.5% above that of Europeans (Quanjer et al. [1987] Pediatr Pulmonol 19:135-142), 14% and 5% above Hispanics reported by (Coultas et al. [1988] Am Rev Respir Dis 138:1386-1392) and (Hsu et al. [1979] J Pediatr 95:14-23), respectively, and 5% above Mexican-Americans from the third National Health and Nutrition Examination Survey study. Similarly, FVC was 8%, 14%, 8%, and 5.6% above the figures predicted by the same authors. The largest errors of prediction of foreign equations occurred in extremely tall or short subjects, and therefore a single proportional adjustment is unfeasible.

Microbial Ecology, 2006

The diterpenoid kaurenoic acid is the main component of the resin from the medicinal plant Pseudo... more The diterpenoid kaurenoic acid is the main component of the resin from the medicinal plant Pseudognaphalium vira vira. As some diterpenoids have antimicrobial properties, the effect of this resin and the kaurenoic acid on soil bacteria was studied. The resin of P. vira vira and purified kaurenoic acid were two to four times more effective as antibacterial agents with Gram-positive than with Gram-negative soil isolates. The chemical stability of kaurenoic acid and the antibacterial activity of both the resin and the diterpenoid were studied in microcosms containing plant-associated soil. After 15 days of incubation, the diterpenoid was stable, as determined by 1 H nuclear magnetic resonance and thin-layer chromatography, and soil extracts still exhibited antibacterial activity. However, after 30 days of incubation, loss of antibacterial activity of soil extracts correlated with removal or chemical modification of kaurenoic acid. The effect of the resin or this diterpenoid on the soil bacteria community was analyzed by the terminal restriction fragment length polymorphisms technique. After 15 days of incubation, the resin and the pure compound caused significant changes in the soil bacterial community. The relative abundance of specific bacterial groups was differentially affected by the resin components, being the effects with the resin stronger than with the kaurenoic acid. After 30 days of incubation, these changes mostly reverted. These results indicate that a plant resin containing diterpenoid compounds plays a significant role controlling specific groups of microorganisms in the soil associated with the plant.

Journal of the American Geriatrics Society, 2000

To compare endothelium-dependent vasomotor response in healthy younger and older subjects without... more To compare endothelium-dependent vasomotor response in healthy younger and older subjects without classic cardiovascular risk factors, with high and normal fasting homocysteine (tHcy) levels. We compared endothelium-dependent vasodilatation, using ultrasound, in healthy younger (aged 18-40) and older (> or =70) people with normal (<13 micromol/L) and high (>15 micromol/L) tHcy levels. Exclusion criteria were smoking, personal history of cardiovascular disease, hypertension, chronic diseases, vitamin intake, obesity, abnormal serum lipids levels, and creatinine higher than 130 micromol/L. Research laboratory. In addition to tHcy levels, serum folate and vitamin B12 levels were measured. We studied 17 younger and 12 older hyperhomocysteinemic subjects and respective aged-matched normohocysteinemic subjects. Endothelium-dependent vasodilatation was lower in the hyperhomocysteinemic older people (P <.01) than in all younger subjects and in normohomocysteinemic older people. Serum vitamin B12 levels were higher in younger and older normal controls. Folic acid levels were higher in younger controls and in both older groups. This study shows an effect of high circulating tHcy on vascular reactivity in older people. Because serum levels of tHcy are associated with nutritional status of vitamin B12 and folic acid, prospective studies are necessary to demonstrate the effects of a long-term nutritional supplementation with vitamins on vascular function and global cardiovascular risk.

Journal of Natural Products, 1999

Two new acylated flavonoids have been isolated from the resinous exudates of Pseudognaphalium rob... more Two new acylated flavonoids have been isolated from the resinous exudates of Pseudognaphalium robustum and Pseudognaphalium cheirantifolium. Their structures were elucidated by high-resolution spectroscopic methods as 5,7,8-trihydroxy-3-methoxyflavone 8-O-[(E)-2-methyl-2-butenoate] (1) and 5,7,8-trihydroxy-3, 6-dimethoxyflavone 8-O-[(E)-2-methyl-2-butenoate] (2).

Journal of Infection, 2007

Objective: Epidemiological studies have shown that most central nervous system (CNS) infections a... more Objective: Epidemiological studies have shown that most central nervous system (CNS) infections are viral. The objective of this study is to contribute to the knowledge base concerning viral CNS infections in Ribeirão Preto, Brazil. Methods: Two hundred cerebrospinal fluid (CSF) samples were taken from patients with clinically suspected viral CNS infection and analyzed for herpesvirus, enterovirus, alphavirus and flavivirus using PCR assays. Results: Viral genome was detected in 43 CSF samples (23.34%): 6% cytomegalovirus (CMV), 5% herpes simplex virus type 1 (HSV-1), 0.5% each varicella-zoster virus (VZV) and EpsteineBarr virus (EBV), and 11.34% enterovirus. Co-infections (CMVeenterovirus and CMVeHSV-1) were found in 3 patients. CSF parameters such as cytology and protein level were normal in many patients with viral genome-positive CSF. Conclusions: Data obtained in this study contribute to the knowledge base concerning viral CNS infections in Brazil. This information will have a major impact on the clinical management of patients with CNS disease.

Journal of Ethnopharmacology, 2006

The antibacterial activity of Haplopappus uncinatus is attributed to a new clerodane diterpenoid,... more The antibacterial activity of Haplopappus uncinatus is attributed to a new clerodane diterpenoid, 18-acetoxy-cis-cleroda-3-en-15-oic acid (10␤H, 16 19␤, 17␤, 20␣ form) (1), isolated as a major component from the resinous exudates of its twigs and leaves, together with the inactive 3,5-dihydroxy-6,7,3 ,4 -tetramethoxyflavone, n-alkanes and a few sesquiterpenoids.

Journal of Ethnopharmacology, 1997

The antimicrobial properties of the resinous exudates from twigs and leaves of four Chilean speci... more The antimicrobial properties of the resinous exudates from twigs and leaves of four Chilean species of Pseudognaphalium: P. viravira, P. robustum, P. heterotrichium and P. cheiranthifolium were tested against six Gram negative bacteria and five Gram positive bacteria. The extracts share similar antimicrobial activities against the Gram positive bacteria. The antimicrobial activity correlated very well with the presence in the resinous exudates of ent -16-kauren-19-oic acid and to a lesser extent with the presence of en t-9(11), 16-kauradien-19-oic. Introduction of an hydrophilic 3 fl-OH drastically reduced the antimicrobial activity of these compound. The activity was not correlated with the flavonoid content of those resinous exudates.

Heredity, 1994

Migration and gene flow of natural enemies play an important role in the stability of predator-pr... more Migration and gene flow of natural enemies play an important role in the stability of predator-prey interactions and community organization in both natural and managed systems. Yet, relative to that of their herbivorous insect prey, the genetic structure of natural enemy populations has been little studied. We present evidence that populations of the predatory coccinellid beetle Coleomegilla maculata (Coleoptera: Coccinellidae), are not genetically subdivided and that levels of gene flow among these populations are extremely high. Furthermore, in the same geographical area, gene flow of C. maculata was significantly (one order of magnitude) greater than that of an abundant prey species, the Colorado potato beetle Leptinotarsa decemlineata (Coleoptera: Chrysomelidae). The high mobility of this natural enemy relative to the insect herbivores on which it feeds may contribute to its effectiveness as a biological control agent in agricultural systems.

World Allergy Organization Journal, 2012

ABSTRACT

Microbial Ecol, 2006

The diterpenoid kaurenoic acid is the main component of the resin from the medicinal plant Pseudo... more The diterpenoid kaurenoic acid is the main component of the resin from the medicinal plant Pseudognaphalium vira vira. As some diterpenoids have antimicrobial properties, the effect of this resin and the kaurenoic acid on soil bacteria was studied. The resin of P. vira vira and purified kaurenoic acid were two to four times more effective as antibacterial agents with Gram-positive than with Gram-negative soil isolates. The chemical stability of kaurenoic acid and the antibacterial activity of both the resin and the diterpenoid were studied in microcosms containing plant-associated soil. After 15 days of incubation, the diterpenoid was stable, as determined by 1 H nuclear magnetic resonance and thin-layer chromatography, and soil extracts still exhibited antibacterial activity. However, after 30 days of incubation, loss of antibacterial activity of soil extracts correlated with removal or chemical modification of kaurenoic acid. The effect of the resin or this diterpenoid on the soil bacteria community was analyzed by the terminal restriction fragment length polymorphisms technique. After 15 days of incubation, the resin and the pure compound caused significant changes in the soil bacterial community. The relative abundance of specific bacterial groups was differentially affected by the resin components, being the effects with the resin stronger than with the kaurenoic acid. After 30 days of incubation, these changes mostly reverted. These results indicate that a plant resin containing diterpenoid compounds plays a significant role controlling specific groups of microorganisms in the soil associated with the plant.

Analytical Biochemistry, Apr 15, 2008

In the present study, we propose a general and accessible method for the resolution of enantiomer... more In the present study, we propose a general and accessible method for the resolution of enantiomeric 1,2-sn-and 2,3-sn-diacylglycerols based on derivatization by isocyanates, which can be easily used routinely by biochemists to evaluate the stereopreferences of lipases in a time course of triacylglycerol (TAG) hydrolysis. Diacylglycerol (DAG) enantiomers were transformed into carbamates using achiral and commercially available reagents. Excellent separation and resolution factors were obtained for diacylglycerols present in lipolysis reaction mixtures. This analytical method was then applied to investigate the stereoselectivity of three model lipases (porcine pancreatic lipase, PPL; lipase from Rhizomucor miehei, MML; and recombinant dog gastric lipase, rDGL) in the time course of hydrolysis of prochiral triolein as a substrate. From the measurements of the diglyceride enantiomeric excess it was confirmed that PPL was not stereospecific (position sn-1 vs sn-3 of triolein), whereas MML and rDGL preferentially hydrolyzed the ester bond at position sn-1 and sn-3, respectively. The enantiomeric excess of DAGs was not constant with time, decreasing with the course of hydrolysis. This was due to the fact that DAGs can be products of the stereospecific hydrolysis of TAGs and substrates for stereospecific hydrolysis into monoacylglycerols.

Talanta, 2015

A Gas Chromatography (GC) method has been developed for the separation and characterization of th... more A Gas Chromatography (GC) method has been developed for the separation and characterization of the different fatty acids in anhydrous milk fat (AMF) by means of an ionic liquid stationary phase, characterized by a monocationic imidazolium salt derived from l-phenylalanine. The inner surface of a fused silica capillary column was modified using this ionic liquid functionality and 3-aminopropyldiethoxymethyl silane. This coated GC column, which exhibited good thermal stability (270°C) and good efficiency (2700 plates/m), has been characterized using the Abraham solvation parameter model. The intra-day and inter-day precision of the method have been evaluated, obtaining relative standard deviations (RSD) from 0.99% to 4.0% and from 2.8% to 9.2%, respectively. Furthermore, recoveries from 90% and 99% have been achieved.

Phytochemistry, 1999

From the resinous exudate of Haplopappus deserticola a new clerodane diterpene named deserticolic... more From the resinous exudate of Haplopappus deserticola a new clerodane diterpene named deserticolic acid (1), the known 18acetoxy-cis-cleroda-3,13E-dien-15-oic acid (2) and four¯avonoids were isolated. The structure of 1 was elucidated as 19hydroxy-cis-cleroda-3,13E-dien-15-oic acid (ent-5a form) by spectroscopic methods. #

Revista chilena de enfermedades respiratorias, 2011

Education is considered a core component of pulmonary rehabilitation. Rather than to simply provi... more Education is considered a core component of pulmonary rehabilitation. Rather than to simply provide didactic education, the recommendation now is to promote self-effi cacy through teaching self-management skills (quality evidence B, moderate recommendation). The main components of self-management education are the use of action plan for early treatment of exacerbations, breathing strategies and bronchial hygiene techniques and the adherence to exercise at home. There still need of evidence about which mechanisms of self-management education have the most perdurable effects.

Hexagon Series on Human and Environmental Security and Peace, 2011

Lack of potable water is an important problem of global dimensions. In Mexico, the northern and c... more Lack of potable water is an important problem of global dimensions. In Mexico, the northern and central regions have significant shortages, a situation which is exacerbated by the pollution of aquifers. Several studies have reported controversial results on high concentrations of heavy metals and halogens in aquifers in the state of Aguascalientes. Poor water quality is caused by the geological conditions in the region, water over-exploitation, and inadequate disposal of industrial waste. However, human exposure to these xenobiotics and their associated toxicological impact has received minimal attention. Many of these contaminants are nephrotoxic agents and this condition is aggravated when they mix.

Physiological and molecular plant pathology, 2008

AvrRxv is a member of a family of pathogen effectors present in pathogens of both plant and mamma... more AvrRxv is a member of a family of pathogen effectors present in pathogens of both plant and mammalian species. Xanthomonas campestris pv. vesicatoria strains carrying AvrRxv induce a hypersensitive response (HR) in the tomato cultivar Hawaii 7998. Using a yeast two-hybrid screen, we identified a 14-3-3 protein from tomato that interacts with AvrRxv called AvrRxv Interactor 1 (ARI1). The interaction was confirmed in vitro with affinity chromatography. Using mutagenesis, we identified a 14-3-3-binding domain in AvrRxv and demonstrated that a mutant in that domain showed concomitant loss of interaction with ARI1 and HR-inducing activity in tomato. These results demonstrate that the AvrRxv bacterial effector recruits 14-3-3 proteins for its function within host cells. AvrRxv homologues YopP and YopJ from Yersinia do not have AvrRxv-specific HR-inducing activity when delivered into tomato host cells by Agrobacterium. Although YopP itself cannot induce HR, its C-terminal domain containing...

Respirology, 2014

Quadriceps muscle dysfunction is an important contributor to exercise limitation in chronic obstr... more Quadriceps muscle dysfunction is an important contributor to exercise limitation in chronic obstructive pulmonary disease, but little is known about skeletal muscle function and its impact on exercise capacity in patients with fibrotic idiopathic interstitial pneumonia (IIP). The aim of the study was to compare quadriceps strength and endurance in patients with fibrotic IIP and healthy controls, and relate it to exercise capacity. Quadriceps strength and endurance, as well as respiratory muscle strength, and 6-min walk distance were compared among 25 patients with fibrotic IIP, forced vital capacity mean (standard deviation) 78.7 (14.0) %predicted, carbon monoxide transfer factor 40.3 (10.9) %predicted and 33 age-matched healthy controls using non-volitional measures. Quadriceps strength was assessed using magnetic femoral nerve stimulation (quadriceps twitch force), and endurance using the decay in force in response to repetitive magnetic stimulation of the quadriceps over 5 min. Both groups had comparable anthropometrics, gender proportion and respiratory muscle strength. Patients were significantly weaker than controls; quadriceps twitch force 10.1 (3.0) kg versus 8.0 (2.4) kg (P = 0.013). Quadriceps force in response to repetitive magnetic stimulation declined significantly more rapidly in patients during the endurance protocol (P < 0.001). In controls, there was a significant relationship between 6-min walk distance and quadriceps twitch force (r 0.40, P = 0.038), and quadriceps endurance (r 0.59, P = 0.016). In patients, only PaO2 and inspiratory muscle strength were retained as independent correlates of 6-min walk distance (r(2) = 0.3 P = 0.022). Quadriceps strength and endurance are reduced in patients with fibrotic IIP compared with healthy controls, but are less tightly correlated with exercise performance.

PLoS ONE, 2013

Our aim was to compare the longitudinal lung function growth of Mexican children and adolescents ... more Our aim was to compare the longitudinal lung function growth of Mexican children and adolescents with the collated spirometric reference proposed for international use and with that of Mexican-Americans from the National Health State Examination Survey III (NHANES) III study.

Pediatric Pulmonology, 2003

We set out to describe the pattern of lung function growth in Mexican students from 8-20 years of... more We set out to describe the pattern of lung function growth in Mexican students from 8-20 years of age, using internationally accepted equipment and methodology, and to compare it to values reported for Mexican-American children. Out of a total of 6,803 students from primary school to high school studied cross-sectionally in the Mexico City metropolitan area, we selected 4,009 asymptomatic, nonobese, nonsmoker subjects to generate spirometric prediction equations. We describe regression equations for the main spirometric variables (log transformed) based on age, height, and weight, and separated for males and females. Spirometric function in the population studied was above that predicted for European (Quanjer et al. [1987] Pediatr Pulmonol 19:135-142) or Mexican-American children, for the same age, height, and gender. On average, forced expiratory volume in 1 sec (FEV(1)) in Mexican children was 9.5% above that of Europeans (Quanjer et al. [1987] Pediatr Pulmonol 19:135-142), 14% and 5% above Hispanics reported by (Coultas et al. [1988] Am Rev Respir Dis 138:1386-1392) and (Hsu et al. [1979] J Pediatr 95:14-23), respectively, and 5% above Mexican-Americans from the third National Health and Nutrition Examination Survey study. Similarly, FVC was 8%, 14%, 8%, and 5.6% above the figures predicted by the same authors. The largest errors of prediction of foreign equations occurred in extremely tall or short subjects, and therefore a single proportional adjustment is unfeasible.

Microbial Ecology, 2006

The diterpenoid kaurenoic acid is the main component of the resin from the medicinal plant Pseudo... more The diterpenoid kaurenoic acid is the main component of the resin from the medicinal plant Pseudognaphalium vira vira. As some diterpenoids have antimicrobial properties, the effect of this resin and the kaurenoic acid on soil bacteria was studied. The resin of P. vira vira and purified kaurenoic acid were two to four times more effective as antibacterial agents with Gram-positive than with Gram-negative soil isolates. The chemical stability of kaurenoic acid and the antibacterial activity of both the resin and the diterpenoid were studied in microcosms containing plant-associated soil. After 15 days of incubation, the diterpenoid was stable, as determined by 1 H nuclear magnetic resonance and thin-layer chromatography, and soil extracts still exhibited antibacterial activity. However, after 30 days of incubation, loss of antibacterial activity of soil extracts correlated with removal or chemical modification of kaurenoic acid. The effect of the resin or this diterpenoid on the soil bacteria community was analyzed by the terminal restriction fragment length polymorphisms technique. After 15 days of incubation, the resin and the pure compound caused significant changes in the soil bacterial community. The relative abundance of specific bacterial groups was differentially affected by the resin components, being the effects with the resin stronger than with the kaurenoic acid. After 30 days of incubation, these changes mostly reverted. These results indicate that a plant resin containing diterpenoid compounds plays a significant role controlling specific groups of microorganisms in the soil associated with the plant.

Journal of the American Geriatrics Society, 2000

To compare endothelium-dependent vasomotor response in healthy younger and older subjects without... more To compare endothelium-dependent vasomotor response in healthy younger and older subjects without classic cardiovascular risk factors, with high and normal fasting homocysteine (tHcy) levels. We compared endothelium-dependent vasodilatation, using ultrasound, in healthy younger (aged 18-40) and older (> or =70) people with normal (<13 micromol/L) and high (>15 micromol/L) tHcy levels. Exclusion criteria were smoking, personal history of cardiovascular disease, hypertension, chronic diseases, vitamin intake, obesity, abnormal serum lipids levels, and creatinine higher than 130 micromol/L. Research laboratory. In addition to tHcy levels, serum folate and vitamin B12 levels were measured. We studied 17 younger and 12 older hyperhomocysteinemic subjects and respective aged-matched normohocysteinemic subjects. Endothelium-dependent vasodilatation was lower in the hyperhomocysteinemic older people (P <.01) than in all younger subjects and in normohomocysteinemic older people. Serum vitamin B12 levels were higher in younger and older normal controls. Folic acid levels were higher in younger controls and in both older groups. This study shows an effect of high circulating tHcy on vascular reactivity in older people. Because serum levels of tHcy are associated with nutritional status of vitamin B12 and folic acid, prospective studies are necessary to demonstrate the effects of a long-term nutritional supplementation with vitamins on vascular function and global cardiovascular risk.

Journal of Natural Products, 1999

Two new acylated flavonoids have been isolated from the resinous exudates of Pseudognaphalium rob... more Two new acylated flavonoids have been isolated from the resinous exudates of Pseudognaphalium robustum and Pseudognaphalium cheirantifolium. Their structures were elucidated by high-resolution spectroscopic methods as 5,7,8-trihydroxy-3-methoxyflavone 8-O-[(E)-2-methyl-2-butenoate] (1) and 5,7,8-trihydroxy-3, 6-dimethoxyflavone 8-O-[(E)-2-methyl-2-butenoate] (2).

Journal of Infection, 2007

Objective: Epidemiological studies have shown that most central nervous system (CNS) infections a... more Objective: Epidemiological studies have shown that most central nervous system (CNS) infections are viral. The objective of this study is to contribute to the knowledge base concerning viral CNS infections in Ribeirão Preto, Brazil. Methods: Two hundred cerebrospinal fluid (CSF) samples were taken from patients with clinically suspected viral CNS infection and analyzed for herpesvirus, enterovirus, alphavirus and flavivirus using PCR assays. Results: Viral genome was detected in 43 CSF samples (23.34%): 6% cytomegalovirus (CMV), 5% herpes simplex virus type 1 (HSV-1), 0.5% each varicella-zoster virus (VZV) and EpsteineBarr virus (EBV), and 11.34% enterovirus. Co-infections (CMVeenterovirus and CMVeHSV-1) were found in 3 patients. CSF parameters such as cytology and protein level were normal in many patients with viral genome-positive CSF. Conclusions: Data obtained in this study contribute to the knowledge base concerning viral CNS infections in Brazil. This information will have a major impact on the clinical management of patients with CNS disease.

Journal of Ethnopharmacology, 2006

The antibacterial activity of Haplopappus uncinatus is attributed to a new clerodane diterpenoid,... more The antibacterial activity of Haplopappus uncinatus is attributed to a new clerodane diterpenoid, 18-acetoxy-cis-cleroda-3-en-15-oic acid (10␤H, 16 19␤, 17␤, 20␣ form) (1), isolated as a major component from the resinous exudates of its twigs and leaves, together with the inactive 3,5-dihydroxy-6,7,3 ,4 -tetramethoxyflavone, n-alkanes and a few sesquiterpenoids.

Journal of Ethnopharmacology, 1997

The antimicrobial properties of the resinous exudates from twigs and leaves of four Chilean speci... more The antimicrobial properties of the resinous exudates from twigs and leaves of four Chilean species of Pseudognaphalium: P. viravira, P. robustum, P. heterotrichium and P. cheiranthifolium were tested against six Gram negative bacteria and five Gram positive bacteria. The extracts share similar antimicrobial activities against the Gram positive bacteria. The antimicrobial activity correlated very well with the presence in the resinous exudates of ent -16-kauren-19-oic acid and to a lesser extent with the presence of en t-9(11), 16-kauradien-19-oic. Introduction of an hydrophilic 3 fl-OH drastically reduced the antimicrobial activity of these compound. The activity was not correlated with the flavonoid content of those resinous exudates.

Heredity, 1994

Migration and gene flow of natural enemies play an important role in the stability of predator-pr... more Migration and gene flow of natural enemies play an important role in the stability of predator-prey interactions and community organization in both natural and managed systems. Yet, relative to that of their herbivorous insect prey, the genetic structure of natural enemy populations has been little studied. We present evidence that populations of the predatory coccinellid beetle Coleomegilla maculata (Coleoptera: Coccinellidae), are not genetically subdivided and that levels of gene flow among these populations are extremely high. Furthermore, in the same geographical area, gene flow of C. maculata was significantly (one order of magnitude) greater than that of an abundant prey species, the Colorado potato beetle Leptinotarsa decemlineata (Coleoptera: Chrysomelidae). The high mobility of this natural enemy relative to the insect herbivores on which it feeds may contribute to its effectiveness as a biological control agent in agricultural systems.