This study evaluated the importance of a correction for amino acids (AA) released into the hindgu... more This study evaluated the importance of a correction for amino acids (AA) released into the hindgut on a measure of AA absorption kinetics and tested whether AA absorption kinetics are related to the extent of AA absorption using the growing pig as a model for humans. Thirty-six nineweek-old pigs (22•3 kg) received a diet containing whey protein as the sole protein source for 8 d. Pigs received their last meal containing the indigestible marker titanium dioxide before being euthanised at 1, 2, 3, 4, 6 and 12 h post-feeding. The entire content of each gastrointestinal tract (GIT) region was collected to determine AA released into the hindgut, and the kinetics and extent of AA absorption (uncorrected and corrected for AA entering the hindgut). Amounts of AA released into the hindgut increased over time (e.g. 33 and 180 mg of Glu for 4 and 6 h post-feeding). The corrected apparent amount of each AA absorbed from the GIT lumen after 4 h post-feeding was generally lower (P ≤ 0•05) than the uncorrected counterpart. Differences in both the kinetics and extent of AA absorption were observed across AA. For example, the time to reach half of the apparent AA absorption (T50) was 1•5 and 3•4 h for Met and Arg, respectively, whereas their extent of apparent absorption was 93 and 73 %. Negative correlations between parameters related to kinetics and the extent of apparent absorption were observed (e.g. for T50 r = −0•81; P < 0•001). The kinetics of AA absorption is related to the extent of AA absorption.
Emerging evidence suggests that alterations in the development of the gastrointestinal (GI) tract... more Emerging evidence suggests that alterations in the development of the gastrointestinal (GI) tract during the early postnatal period can influence brain development and viceversa. It is increasingly recognized that communication between the GI tract and brain is mainly driven by neural, endocrine, immune, and metabolic mediators, collectively called the gut-brain axis (GBA). Changes in the GBA mediators occur in response to the developmental changes in the body during this period. This review provides an overview of major developmental events in the GI tract and brain in the early postnatal period and their parallel developmental trajectories under physiological conditions. Current knowledge of GBA mediators in context to brain function and behavioral outcomes and their synthesis and metabolism (site, timing, etc.) is discussed. This review also presents hypotheses on the role of the GBA mediators in response to the parallel development of the GI tract and brain in infants.
A recently proposed paradigm suggests that, like their dietary counterparts, digestion of gastroi... more A recently proposed paradigm suggests that, like their dietary counterparts, digestion of gastrointestinal endogenous proteins (GEP) may also produce bioactive peptides. With an aim to test this hypothesis, in vitro digests of four GEP namely; trypsin (TRYP), lysozyme (LYS), mucin (MUC), serum albumin (SA) and a dietary protein chicken albumin (CA) were screened for their angiotensin-I converting (ACE-I), renin, platelet-activating factor-acetylhydrolase (PAF-AH) and dipeptidyl peptidase-IV inhibitory (DPP-IV) and antioxidant potential following simulated in vitro gastrointestinal digestion. Further, the resultant small intestinal digests were enriched to obtain peptides between 3-10 kDa in size. All in vitro digests of the four GEP were found to inhibit ACE-I compared to the positive control captopril when assayed at a concentration of 1 mg/mL, while the LYS < 3-kDa permeate fraction inhibited renin by 40% (±1.79%). The LYS < 10-kDa fraction inhibited PAF-AH by 39% (±4.34%), ...
This article proposes a new way to improve the protein quality of the common bean (Phaseolus vulg... more This article proposes a new way to improve the protein quality of the common bean (Phaseolus vulgaris). It is based on the natural variability found in the different types of phaseolin, its main storage protein (40-50% of the total protein). Despite the fact that it is deficient in methionine content, phaseolin still represents the main source of that amino acid in the seed. More than 40 genetic variants, differing in subunit number (2-6) and molecular weight (40-54 kDa) have been analyzed. The similarity of the amino acid composition among phaseolins, suggests that a nutritional improvement cannot be expected from that side. Conversely, important variation in phaseolin susceptibility to proteolysis (ranging from 57% to 96% after cooking) has been observed, increasing the theoretical availability of methionine by up to 37%. Therefore, breeding programs based on highly-digestible phaseolin types could lead to the production of beans with higher protein quality.
The effect of kiwi fruit at two dietary levels on the adaptation of intestinal fermentation over ... more The effect of kiwi fruit at two dietary levels on the adaptation of intestinal fermentation over time in the growing pig was studied. A semi-synthetic fibre-free diet and two semi-synthetic diets containing kiwi fruit as a model fibre source (133 or 266 g/kg (DM basis); 28 or 48 g fibre/kg) were formulated and the diets contained titanium dioxide as an indigestible marker. A total of fourteen ileal cannulated pigs (41 kg body weight) were fed the fibre-free diet for 7 d followed by either the low or high kiwi fruit-containing diets (n 7/diet) for a further 44 d. Ileal digesta and faeces were collected at five times throughout the study. Ileal digesta were fermented (in vitro) with a standard pooled human faecal inoculum, while fresh pig faeces were used as inocula to ferment in vitro a standard purified fibre. Observations were normalised for diet DM intake using the marker. The 16S ribosomal RNA gene copy number of ileal and total faecal bacteria were high for the high-kiwi fruit l...
The Journal of Deaf Studies and Deaf Education, 2017
Deaf children with cochlear implants (CIs) are at risk for psychosocial adjustment problems, poss... more Deaf children with cochlear implants (CIs) are at risk for psychosocial adjustment problems, possibly due to delayed speechlanguage skills. This study investigated associations between a core component of spoken-language ability-speech intelligibility-and the psychosocial development of prelingually deaf CI users. Audio-transcription measures of speech intelligibility and parent reports of psychosocial behaviors were obtained for two age groups (preschool, school-age/teen). CI users in both age groups scored more poorly than typically hearing peers on speech intelligibility and several psychosocial scales. Among preschool CI users, five scales were correlated with speech intelligibility: functional communication, attention problems, atypicality, withdrawal, and adaptability. These scales and four additional scales were correlated with speech intelligibility among school-age/teen CI users: leadership, activities of daily living, anxiety, and depression. Results suggest that speech intelligibility may be an important contributing factor underlying several domains of psychosocial functioning in children and teens with CIs, particularly involving socialization, communication, and emotional adjustment. The auditory input provided by a cochlear implant (CI) dramatically improves the speech perception and spoken language skills of prelingually deaf children, especially when implantation occurs at an early age (e.g.
The study aimed to investigate thein vivodigestion ofPhaseolus vulgarisphaseolin types differing ... more The study aimed to investigate thein vivodigestion ofPhaseolus vulgarisphaseolin types differing in their subunit pattern composition. Diets contained either casein as the sole source of protein or a mixture (1:1) of casein and pure Sanilac (S), Tendergreen (T) or Inca (I) phaseolin either unheated or heated. Rats were fed for 11 d with the experimental diets. Their ileal content and mucosa were collected and prepared for electrophoresis, Western blotting, densitometry and MS. Differences in digestion among native phaseolin types were observed for intact phaseolin at molecular weights (MW) of 47–50·5 kDa and for an undigested fragment at MW of 19–21·5 kDa in ileal digesta. In both cases, the concentration of these protein bands was lower for I phaseolin than for S or T phaseolin (P < 0·05). In the mucosa, the concentration of a protein band at MW of 20·5–21·5 kDa was lower for S phaseolin as compared to T or I phaseolin (P < 0·001). The presence of phaseolin subunits and their...
We present the first results from the Calán-Yale Deep Extragalactic Research (CYDER) survey. The ... more We present the first results from the Calán-Yale Deep Extragalactic Research (CYDER) survey. The main goal of this survey is to study serendipitous X-ray sources detected by Chandra in an intermediate flux range (10 À15 to 10 À12 ergs s À1) that comprises most of the X-ray background. A total of 267 X-ray sources spread over five archived fields were detected. The log N log S distribution obtained for this sample is consistent with the results of other surveys. Deep V and I images were taken of these fields in order to calculate X-ray-to-optical flux ratios. Identifications and redshifts were obtained for 106 sources using optical spectroscopy from 8 m class telescopes to reach the optically faintest sources, to the same level as deeper X-ray fields like the Chandra Deep Fields, showing that the nature of sources detected depends mostly on the optical limit for spectroscopy. In general, sources optically classified as obscured active galactic nuclei (AGNs) have redder optical colors than unobscured AGNs. A rough correlation between f X =f opt and hard X-ray luminosity was found for obscured AGNs, confirming the prediction by existing models that in obscured AGNs the optical light is completely dominated by the host galaxy. The previously claimed decrease of the obscured-to-unobscured AGN ratio with increasing X-ray luminosity is observed. However, this correlation can be explained as a selection effect caused by the lower optical flux of obscured AGNs. Comparison between the observed N H distribution and predictions by existing models shows that the sample appears complete up to N H < 3 ; 10 22 cm À2 , while for more obscured sources incompleteness plays an important role in the observed obscured-to-unobscured AGN ratio. Subject headingg s: galaxies: active-quasars: general-surveys-X-rays: diffuse background-X-rays: galaxies Online material: machine-readable table 1 Partly based on observations collected at the European Southern Observatory, Chile, under programs 68.A-0459 and 72.A-0509.
By simulating the explosion of hot drops of classical particles, phase separation scenarios and t... more By simulating the explosion of hot drops of classical particles, phase separation scenarios and the hypotheses of critical phenomena are tested microscopically. Power law behavior is indeed observed in the mass distribution for excitations corresponding to maximum ...
This study evaluated the importance of a correction for amino acids (AA) released into the hindgu... more This study evaluated the importance of a correction for amino acids (AA) released into the hindgut on a measure of AA absorption kinetics and tested whether AA absorption kinetics are related to the extent of AA absorption using the growing pig as a model for humans. Thirty-six nineweek-old pigs (22•3 kg) received a diet containing whey protein as the sole protein source for 8 d. Pigs received their last meal containing the indigestible marker titanium dioxide before being euthanised at 1, 2, 3, 4, 6 and 12 h post-feeding. The entire content of each gastrointestinal tract (GIT) region was collected to determine AA released into the hindgut, and the kinetics and extent of AA absorption (uncorrected and corrected for AA entering the hindgut). Amounts of AA released into the hindgut increased over time (e.g. 33 and 180 mg of Glu for 4 and 6 h post-feeding). The corrected apparent amount of each AA absorbed from the GIT lumen after 4 h post-feeding was generally lower (P ≤ 0•05) than the uncorrected counterpart. Differences in both the kinetics and extent of AA absorption were observed across AA. For example, the time to reach half of the apparent AA absorption (T50) was 1•5 and 3•4 h for Met and Arg, respectively, whereas their extent of apparent absorption was 93 and 73 %. Negative correlations between parameters related to kinetics and the extent of apparent absorption were observed (e.g. for T50 r = −0•81; P < 0•001). The kinetics of AA absorption is related to the extent of AA absorption.
Emerging evidence suggests that alterations in the development of the gastrointestinal (GI) tract... more Emerging evidence suggests that alterations in the development of the gastrointestinal (GI) tract during the early postnatal period can influence brain development and viceversa. It is increasingly recognized that communication between the GI tract and brain is mainly driven by neural, endocrine, immune, and metabolic mediators, collectively called the gut-brain axis (GBA). Changes in the GBA mediators occur in response to the developmental changes in the body during this period. This review provides an overview of major developmental events in the GI tract and brain in the early postnatal period and their parallel developmental trajectories under physiological conditions. Current knowledge of GBA mediators in context to brain function and behavioral outcomes and their synthesis and metabolism (site, timing, etc.) is discussed. This review also presents hypotheses on the role of the GBA mediators in response to the parallel development of the GI tract and brain in infants.
A recently proposed paradigm suggests that, like their dietary counterparts, digestion of gastroi... more A recently proposed paradigm suggests that, like their dietary counterparts, digestion of gastrointestinal endogenous proteins (GEP) may also produce bioactive peptides. With an aim to test this hypothesis, in vitro digests of four GEP namely; trypsin (TRYP), lysozyme (LYS), mucin (MUC), serum albumin (SA) and a dietary protein chicken albumin (CA) were screened for their angiotensin-I converting (ACE-I), renin, platelet-activating factor-acetylhydrolase (PAF-AH) and dipeptidyl peptidase-IV inhibitory (DPP-IV) and antioxidant potential following simulated in vitro gastrointestinal digestion. Further, the resultant small intestinal digests were enriched to obtain peptides between 3-10 kDa in size. All in vitro digests of the four GEP were found to inhibit ACE-I compared to the positive control captopril when assayed at a concentration of 1 mg/mL, while the LYS < 3-kDa permeate fraction inhibited renin by 40% (±1.79%). The LYS < 10-kDa fraction inhibited PAF-AH by 39% (±4.34%), ...
This article proposes a new way to improve the protein quality of the common bean (Phaseolus vulg... more This article proposes a new way to improve the protein quality of the common bean (Phaseolus vulgaris). It is based on the natural variability found in the different types of phaseolin, its main storage protein (40-50% of the total protein). Despite the fact that it is deficient in methionine content, phaseolin still represents the main source of that amino acid in the seed. More than 40 genetic variants, differing in subunit number (2-6) and molecular weight (40-54 kDa) have been analyzed. The similarity of the amino acid composition among phaseolins, suggests that a nutritional improvement cannot be expected from that side. Conversely, important variation in phaseolin susceptibility to proteolysis (ranging from 57% to 96% after cooking) has been observed, increasing the theoretical availability of methionine by up to 37%. Therefore, breeding programs based on highly-digestible phaseolin types could lead to the production of beans with higher protein quality.
The effect of kiwi fruit at two dietary levels on the adaptation of intestinal fermentation over ... more The effect of kiwi fruit at two dietary levels on the adaptation of intestinal fermentation over time in the growing pig was studied. A semi-synthetic fibre-free diet and two semi-synthetic diets containing kiwi fruit as a model fibre source (133 or 266 g/kg (DM basis); 28 or 48 g fibre/kg) were formulated and the diets contained titanium dioxide as an indigestible marker. A total of fourteen ileal cannulated pigs (41 kg body weight) were fed the fibre-free diet for 7 d followed by either the low or high kiwi fruit-containing diets (n 7/diet) for a further 44 d. Ileal digesta and faeces were collected at five times throughout the study. Ileal digesta were fermented (in vitro) with a standard pooled human faecal inoculum, while fresh pig faeces were used as inocula to ferment in vitro a standard purified fibre. Observations were normalised for diet DM intake using the marker. The 16S ribosomal RNA gene copy number of ileal and total faecal bacteria were high for the high-kiwi fruit l...
The Journal of Deaf Studies and Deaf Education, 2017
Deaf children with cochlear implants (CIs) are at risk for psychosocial adjustment problems, poss... more Deaf children with cochlear implants (CIs) are at risk for psychosocial adjustment problems, possibly due to delayed speechlanguage skills. This study investigated associations between a core component of spoken-language ability-speech intelligibility-and the psychosocial development of prelingually deaf CI users. Audio-transcription measures of speech intelligibility and parent reports of psychosocial behaviors were obtained for two age groups (preschool, school-age/teen). CI users in both age groups scored more poorly than typically hearing peers on speech intelligibility and several psychosocial scales. Among preschool CI users, five scales were correlated with speech intelligibility: functional communication, attention problems, atypicality, withdrawal, and adaptability. These scales and four additional scales were correlated with speech intelligibility among school-age/teen CI users: leadership, activities of daily living, anxiety, and depression. Results suggest that speech intelligibility may be an important contributing factor underlying several domains of psychosocial functioning in children and teens with CIs, particularly involving socialization, communication, and emotional adjustment. The auditory input provided by a cochlear implant (CI) dramatically improves the speech perception and spoken language skills of prelingually deaf children, especially when implantation occurs at an early age (e.g.
The study aimed to investigate thein vivodigestion ofPhaseolus vulgarisphaseolin types differing ... more The study aimed to investigate thein vivodigestion ofPhaseolus vulgarisphaseolin types differing in their subunit pattern composition. Diets contained either casein as the sole source of protein or a mixture (1:1) of casein and pure Sanilac (S), Tendergreen (T) or Inca (I) phaseolin either unheated or heated. Rats were fed for 11 d with the experimental diets. Their ileal content and mucosa were collected and prepared for electrophoresis, Western blotting, densitometry and MS. Differences in digestion among native phaseolin types were observed for intact phaseolin at molecular weights (MW) of 47–50·5 kDa and for an undigested fragment at MW of 19–21·5 kDa in ileal digesta. In both cases, the concentration of these protein bands was lower for I phaseolin than for S or T phaseolin (P < 0·05). In the mucosa, the concentration of a protein band at MW of 20·5–21·5 kDa was lower for S phaseolin as compared to T or I phaseolin (P < 0·001). The presence of phaseolin subunits and their...
We present the first results from the Calán-Yale Deep Extragalactic Research (CYDER) survey. The ... more We present the first results from the Calán-Yale Deep Extragalactic Research (CYDER) survey. The main goal of this survey is to study serendipitous X-ray sources detected by Chandra in an intermediate flux range (10 À15 to 10 À12 ergs s À1) that comprises most of the X-ray background. A total of 267 X-ray sources spread over five archived fields were detected. The log N log S distribution obtained for this sample is consistent with the results of other surveys. Deep V and I images were taken of these fields in order to calculate X-ray-to-optical flux ratios. Identifications and redshifts were obtained for 106 sources using optical spectroscopy from 8 m class telescopes to reach the optically faintest sources, to the same level as deeper X-ray fields like the Chandra Deep Fields, showing that the nature of sources detected depends mostly on the optical limit for spectroscopy. In general, sources optically classified as obscured active galactic nuclei (AGNs) have redder optical colors than unobscured AGNs. A rough correlation between f X =f opt and hard X-ray luminosity was found for obscured AGNs, confirming the prediction by existing models that in obscured AGNs the optical light is completely dominated by the host galaxy. The previously claimed decrease of the obscured-to-unobscured AGN ratio with increasing X-ray luminosity is observed. However, this correlation can be explained as a selection effect caused by the lower optical flux of obscured AGNs. Comparison between the observed N H distribution and predictions by existing models shows that the sample appears complete up to N H < 3 ; 10 22 cm À2 , while for more obscured sources incompleteness plays an important role in the observed obscured-to-unobscured AGN ratio. Subject headingg s: galaxies: active-quasars: general-surveys-X-rays: diffuse background-X-rays: galaxies Online material: machine-readable table 1 Partly based on observations collected at the European Southern Observatory, Chile, under programs 68.A-0459 and 72.A-0509.
By simulating the explosion of hot drops of classical particles, phase separation scenarios and t... more By simulating the explosion of hot drops of classical particles, phase separation scenarios and the hypotheses of critical phenomena are tested microscopically. Power law behavior is indeed observed in the mass distribution for excitations corresponding to maximum ...
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Papers by Carlos Montoya