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A M Teixeira

Publications and source records attributed to A M Teixeira.

At least 19 recordsLinked to original sources
PubMed2001

Homophilic adhesion of human CEACAM1 involves N-terminal domain interactions: structural analysis of the binding site.

CEACAM1 on leukocytic, endothelial, and epithelial cells functions in homophilic adhesion, tumor suppression, regulating cell adhesion and proliferation, and in heterophilic adhesion as a receptor for E-selectin and Neisseria meningiditis, Neisseria gonorrhoeae, Haemophilus influenzae, and murine coronaviruses. The 8 transmembrane isoforms of human CEACAM1 possess an extracellular N-terminal IgV domain, followed by variable numbers of IgC2 domains. To establish which key amino acids contribute specifically to CEACAM1 homophilic adhesion, exposed amino acids in the N-terminal domain of a soluble form of CEACAM1 were subjected to mutagenesis. Analyses of mutant proteins with conformationally dependent antibodies indicated that most mutations did not substantially affect the structural integrity of CEACAM1. Nevertheless, decreased adhesion was observed for the single mutants V39A or D40A (single-letter amino acid codes) in the CC' loop and for the triple mutants located in the GFCC'C" face of the N-terminal domain. Interestingly, whereas single mutations in R64 or D82 that are predicted to form a salt bridge between the base of the D and F beta strands close to the critical V39 and D40 residues also abolish adhesion, an amino acid swap (R64D and D82R), which maintains the salt bridge was without significant effect. These studies indicate that the CC' loop plays a crucial role in the homophilic adhesion of CEACAM1. They further predict that specific hydrophobic amino acid residues on the nonglycosylated GFCC'C" face of CEACAM1 N-terminal domain are not only involved in heterophilic interactions with Opa proteins and H influenzae, but are also critical for protein-protein interactions between 2 CEACAM1 molecules on opposing cells.

Amino Acid Sequence↗
PubMed1999

Critical determinants of host receptor targeting by Neisseria meningitidis and Neisseria gonorrhoeae: identification of Opa adhesiotopes on the N-domain of CD66 molecules.

The human pathogens Neisseria meningitidis and Neisseria gonorrhoeae express a family of variable outer membrane opacity-associated (Opa) proteins that recognize multiple human cell surface receptors. Most Opa proteins target the highly conserved N-terminal domain of the CD66 family of adhesion molecules, although a few also interact with heparan sulphate proteoglycans. In this study, we observed that at least two Opa proteins of a N. meningitidis strain C751 have the dual capacity to interact with both receptors. In addition, all three Opa proteins of C751 bind equally well to HeLa cells transfected with cDNA encoding the carcinoembryonic antigen [CEA (CD66e)] subgroup of the CD66 family, but show distinct tropism for CGM1- (CD66d) and NCA (CD66c)-expressing cells. Because the C751 Opa proteins make up distinct structures via the surface-exposed hypervariable domains (HV-1 and HV-2), these combinations appear to be involved in tropism for the distinct CD66 subgroups. To define the determinants of receptor recognition, we used mutant proteins of biliary glycoprotein [BGP (CD66a)] carrying substitutions at several predicted exposed sites in the N-domain and compared their interactions with several Opa proteins of both N. meningitidis and N. gonorrhoeae. The observations applied to the molecular model of the BGP N-domain that we constructed show that the binding of all Opa proteins tested occurs at the non-glycosylated (CFG) face of the molecule and, in general, appears to require Tyr-34 and Ile-91. Further, efficient interaction of distinct Opa proteins depends on different non-adjacent amino acids. In the three-dimensional model, these residues lie in close proximity to Tyr-34 and Ile-91 at the CFG face, making continuous binding domains (adhesiotopes). The epitope of the monoclonal antibody YTH71.3 that inhibits Opa/CD66 interactions was also identified within the Opa adhesiotopes on the N-domain. These studies define the molecular basis that directs the Opa specificity for the CD66 family and the rationale for tropism of the Opa proteins for the CD66 subgroups.

Amino Acid Sequence↗
PubMed1998

Analysis of surface markers on CD34+ cells, isolated from cord blood and G-CSF primed peripheral blood.

We report a comparative study of the expression of multilineage and adhesion molecules on CD34+ cells isolated from human umbilical cord blood (CB) and G-CSF-mobilized peripheral blood progenitor cells (PBPC) from healthy volunteers. The major difference found between the two sources of CD34+ populations was the expression of CD54 molecule, which was higher in CB in comparison to PBPC.

Antigens, CD↗
PubMed1997

[Suicide, self-mutilation and poisoning in adolescents: an epidemiological study].

This is an epidemiological study on Self-Inflicted Suicide and Lesions (E950 to E959) that we do not know if they are accidentally or intentionally inflicted (E980 to E989) among adolescents attended in a Psychiatric Ward at an Emergency Service in Ribeirão Preto, S.P., Brazil, from 1988 to 1991. The diagnoses were grouped according to CID-9. Data were obtained from the Hospital Statistics Service. The feminine sex predominated in the 4 years and in both diagnoses. It was observed that the occurrence of E950 to E959 increased during the period, while the occurrence of E980 to E989 decreased among the adolescents.

Adolescent↗
PubMed1994

The N-domain of the biliary glycoprotein (BGP) adhesion molecule mediates homotypic binding: domain interactions and epitope analysis of BGPc.

The biliary glycoproteins (BGPs) represent a group of at least eight differentially spliced molecules belonging to the carcinoembryonic antigen (CEA) subgroup of the CEA family. These molecules are recognized by the CD66 monoclonal antibodies (MoAbs) and function as homotypic and heterotypic adhesion molecules. The extracellular region of the BGPc splice variant comprises an N-terminal IgV-like domain and three IgC2-set domains (A1, B1, and A2). Using soluble recombinant BGP domain variants, we demonstrate in this report that the N-terminal domain mediates homotypic adhesion. Furthermore, this adhesion is both temperature- and cation-dependent. The soluble domain variants of BGP are ideal molecules for epitope mapping. Using these constructs, we have mapped 11 MoAbs that react with the CEA family to different domains of BGPc and have shown that the CD66 MoAbs, YTH71.3.2 and CLBgran 10 (M38), recognize epitopes in the N-terminal domain.

Animals↗
PubMed1994

CD66 identifies the biliary glycoprotein (BGP) adhesion molecule: cloning, expression, and adhesion functions of the BGPc splice variant.

Within the hematopoietic lineage, the monoclonal antibody (MoAb) CD66 reacts with cells of the granulocyte lineage, but not with the majority of progenitor cells from human bone marrow. Our previous studies have shown that CD66 binds specifically to at least three carcinoembryonic antigen (CEA) superfamily members, ie, CEA itself, nonspecific cross-reacting antigen (NCA), and CGM1, but not to CGM6 (NCA-95). In this report, we show that CD66 will also identify the biliary glycoproteins (BGP). A full-length cDNA for the BGPc molecule (a cytoplasmic splice variant of BGPa) was isolated by expression cloning using the CD66 MoAbs. This protein has an identical extracellular and transmembrane sequence to BGPa with one N-terminal IgV like domain, three IgC-like extracellular domains (A1, B1, and A2), plus a transmembrane domain, but the cytoplasmic domain is spliced by 53 nucleotides. Reverse transcriptase-polymerase chain reaction experiments show that this splice variant can be detected in colonic carcinoma cell lines, in primary colonic adenocarcinomas, and in myeloid and B-cell lines to varying degrees. Quantitative analyses of BGPc RNA expression by RNase protection indicate that abundant levels occur only in the colonic, but not in the hematopoietic, cell lines tested. Studies presented here show that BGPc mediates homotypic adhesion and suggest that the cytoplasmic splicing does not alter the initial homotypic adhesion properties of BGPa.

Amino Acid Sequence↗
PubMed1994

[Promotion of breast-feeding in urban localities of southern Brazil: a randomized intervention study].

A randomized intervention trial to promote breast-feeding was carried out in southern Brazil. A group of 450 mothers and babies was visited at home 5, 10 and 20 days after birth and compared to a non-visited control group of the same size. Ninety-two per cent of the families visited received the three home visits planned. The evaluation of breast-feeding patterns and reasons for weaning took place 6 months after birth for both groups. Ninety-four per cent of the group visited and 92% of the non-visited controls group were traced on the occasion of the assessment. The intervention increased the duration of breast-feeding (median duration of 120 days in the group visited and 105 days in the controls; p = 0.03) and delayed the introduction of milk bottles (median age of introduction of 90 days in the group visited and 60 days in the controls; p = 0.01). Causes of weaning were classified as underlying, intermediate and immediate. The most common underlying cause of weaning was "the baby cried too much", which suggests that mothers should be taught about normal patterns of infant behaviour in the first weeks of life, particularly the need for crying, and the fact that this not necessarily reflects hunger.

Adult↗
PubMed1992

Early childhood mortality in a Brazilian cohort: the roles of birthweight and socioeconomic status.

The deaths of children aged 1-4 years were studied in a cohort of 5914 Brazilian liveborns. A total of 29 early childhood deaths were recorded (cumulative mortality risk of approximately 6 per 1000), 17 of which (59%) were due to infectious diseases. The death rate was highest in the second year. Deaths were highly concentrated in children from low income (< US $50/month) families, where the cumulative risk of early childhood death was about 10 per 1000; on the other hand, there were no deaths among the 616 children from families with a monthly income of US $300 or more. Birthweight was also associated with mortality: the cumulative risk of children weighing less than 2000 g at birth was 21 per 1000, compared to 4 per 1000 among those with birthweights of 3500 g or more. Simultaneous adjustment for income and birthweight did not substantially change these differentials. These findings confirm the strong association between early childhood mortality and socioeconomic conditions, but also make evident the long-term effects of low birthweight.

Birth Weight↗
PubMed1992

[Stapling in surgery of cancer of the rectum. Experience with 100 cases].

The authors relate their experience with 100 cases of anterior resections operated using stapling techniques, 43 with double stapling. Fifty three were males and forty seven females, the youngest being 35 year's old and the oldest 87. The tumour was located at the upper third in 54 cases, at the middle third in 41 and at the lower third in five cases. One hundred anterior resections were executed, fifty of the low type. As to the Dukes classification, 15 were A type, 45 type B, 35 type C and 5 type D. There were no operative mortality until the 30th post operative day. As early post-operative complications there were one case of hemorrhage, two pneumopathies, one urinary retention, one cardio-respiratory insufficiency three cases of fistulae and 6 wound infections. In the last 65 cases only one wound infection and two pneumopathies were found. As late complications there were three anastomotic stenosis (all of them satisfactorily solved with dilatation) and six cases with small degree incontinence for gas and faeces recovering spontaneously. The recurrence rate was 14%; in three it has been possible to proceed with its excision by means of abdominoperineal amputation. They conclude stating that mechanical suturing specially is a good alternative to manual suturing in patients with low rectal tumours.

Adult↗
PubMed1991

The timing of nutritional status determination: implications for interventions and growth monitoring.

A population-based birth cohort of 1226 urban Brazilian children underwent anthropometric examinations at, on average, ages 11, 23 and 47 months. Multiple regression analyses showed that while birth weight was the single most important factor in predicting nutritional status at age 11 months, a wide range of other social, biological and morbidity factors also appeared to play a significant role. Environmental and dietary factors, however, showed no significant association. Nutritional status at age 11 months was a very strong predictor of nutritional status at ages 23 and 47 months and the other explanatory factors made a minimal additional contribution to the regression models. These results suggest that, in this population, childhood nutritional status is primarily determined before the end of the first year of life. These findings have implications for the timing and nature of nutritional interventions and for mechanisms for identifying those children who will suffer from poor nutritional status later in childhood.

Body Height↗
PubMed1989

Infant feeding and deaths due to diarrhea. A case-control study.

The association between infant feeding habits and infant mortality from diarrhea was investigated in a population-based case-control study in two urban areas in southern Brazil during 1985. Each of 170 infants who died due to diarrhea was compared with two neighborhood controls. After allowance was made for confounding variables, infants who received powdered milk or cow's milk, in addition to breast milk, were at 4.2 times (95% confidence interval (CI) 1.7-10.1) the risk of death from diarrhea compared with infants who did not receive artificial milk, while the risk for infants who did not receive any breast milk was 14.2 times higher (95% CI 5.9-34.1). Similar results were obtained when infants who died from diarrhea were compared with infants who died from diseases that were presumed to be due to noninfectious causes. Each additional daily breast feed reduced the risk of diarrhea death by 20% (95% CI 2-34%), but the increase in risk associated with each bottle feed was not significant after allowance was made for the number of breast feeds. The only other consumption variable associated with diarrhea mortality was the frequency with which tea, water, or juice were drunk with each feed (increase in risk, 42% (95% CI 4-93%]. The odds ratios associated with nonbreast milk were highest in the first two months of life. Possible biases were investigated, including the interruption of breast-feeding as an early consequence of the terminal illness, but the strong protective effect of breast-feeding persisted after these adjustments.

Animals↗
PubMed1989

[Evaluation of the quality of information on the basic cause of death of infants in Rio Grande do Sul (Brazil)].

The validity of the official information on the cause of infant deaths was studied in the Brazilian cities of Porto Alegre and Pelotas in 1985. Using data collected for a population-based case-control study of infant mortality due to infectious diseases or malnutrition, a comparison was made between the causes of death reported on the death certificates and those obtained after a careful review of case-notes and a medical interview with the parents of the decreased infants. Official death certificates showed an excess of deaths attribute to bronchopneumonia (ICD 485X) and septicemia (ICD 038.9), and an underestimation of the number of deaths due to diarrheal diseases (ICD 009.1) and of sudden infant deaths (ICD 798.0). The overall rate of agreement between official and revised certificates, in terms of groups of causes of death, was only 27.9%. Lower respiratory infections, which were the leading infectious cause of infant death according to official statistics, were superseded by diarrheal diseases after this revision.

Brazil↗
PubMed1988

Water supply, sanitation and housing in relation to the risk of infant mortality from diarrhoea.

In a population-based case-control study in the metropolitan areas of Porto Alegre and Pelotas in southern Brazil children dying in infancy from diarrhoea were compared to neighbourhood controls in terms of several social and environmental variables. Factors found to be significantly associated with an increased risk of death from diarrhoea included the non-availability of piped water, the absence of a flush toilet, residence in a poorly built house and household overcrowding. When adjustment was made for confounding variables and the mutual confounding effect of the environmental variables on each other, the only association that remained statistically significant was that with the availability of piped water. The association with poor housing was almost significant (p = 0.052). Compared to those with water piped to their house, those without easy access to piped water were found to be 4.8 times more likely to suffer infant death from diarrhoea (95% confidence interval 1.7 to 13.8) and those with water piped to their plot but not to their house had a 1.5 times greater risk (95% confidence interval 0.8 to 3.0).

Brazil↗
PubMed1988

Influence of birth weight on mortality from infectious diseases: a case-control study.

The association between birth weight and infant mortality from infectious diseases was investigated in a population-based case-control study in two urban areas in southern Brazil. All deaths of children, seven to 364 days of age, occurring in a year were studied and the parents of the 357 infants dying of an infectious cause were interviewed, as were the parents of two neighborhood control infants for each case. Low birth weight infants (less than 2,500 g) were found, after allowing for confounding factors, to be 2.3 (90% confidence interval = 1.6 to 3.4) times more likely to die of an infection than those of higher birth weight. The odds ratios were 2.0 (1.1 to 3.6) for deaths due to diarrhea, 1.9 (1.0 to 3.6) for respiratory infections, and 5.0 (1.3 to 18.6) for other infections. These estimates of the risks associated with low birth weight are considerably lower than those from studies in developed countries.

Birth Weight↗
PubMed1987

Evidence for protection by breast-feeding against infant deaths from infectious diseases in Brazil.

In a population-based case-control study of infant mortality in two urban areas of southern Brazil, the type of milk in an infant's diet was found to be an important risk factor for deaths from diarrhoeal and respiratory infections. Compared with infants who were breast-fed with no milk supplements, and after adjusting for confounding variables, those completely weaned had 14.2 and 3.6 times the risk of death from diarrhoea and respiratory infections, respectively. Part-weaning was associated with corresponding relative risks (RR) of 4.2 and 1.6. The risk of death from infections other than diarrhoea or respiratory infection was less clearly associated with breast-feeding (completely weaned, RR = 2.5; partly weaned, RR = 0.4). Cow's and formula milk seemed to be equally hazardous. For deaths due to diarrhoea the increased risk associated with not breast-feeding was greatest in the first two months of life (RR for completely weaned vs breast-fed without supplementary milk = 23.3).

Animals↗
PubMed1987

Birthweight and infant mortality: a longitudinal study of 5914 Brazilian children.

In a population-based cohort study in Southern Brazil, 87.3% of 5914 liveborn infants were followed for over 12 months. The 215 infant deaths occurring in this cohort were studied in relation to birthweight, gestational age and socioeconomic status. Causes of death were ascertained through the review of case notes and interviews with the parents. As predicted, there was a strong inverse association between birthweight and neonatal and postneonatal mortality. Preterm infants with an adequate weight for their gestational age, despite being slightly heavier than small-for-dates, showed an IMR which was twice as large as the latter. The relative risk associated with low birthweight for deaths due to respiratory infections was over twice as large as that for diarrhoea deaths, but there were only 25 deaths in each category and the estimates are therefore not very precise. There was an interaction between birthweight and socioeconomic status, with the relative risk of mortality associated with low birthweight being much larger among rich than among poor infants. Estimates of the magnitude of the reduction in infant mortality which would accompany a given improvement in the birthweight distribution, which have been mostly based on data from developed countries, may prove to be overoptimistic.

Brazil↗