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Biomedical subjects

R Almeida

Publications and source records attributed to R Almeida.

At least 19 recordsLinked to original sources
PubMed2006

Influence of climatic and management factors on Eimeria infections in goats from semi-arid zones.

A survey of Eimeria infections was performed in dairy goats and kids (<6 months old) of six farms from a dry desert area of Gran Canaria Island (Spain). The number of oocysts per gram of faeces (OPG) was determined by a modified McMaster technique over a total of 2,616 individual faecal samples taken from the rectum in monthly intervals. Eimeria oocysts were found in 96.1% of the samples with OPG ranging from 1 x 10(2) to 1.4 x 10(6). Kid goats had significantly (P < 0.001) higher OPG counts (46,496 +/- 5,228) than dairy females (2,225 +/- 287). Eight Eimeria species were identified, with Eimeria ninakohlyakimovae (30.0%), Eimeria arloingi (28.6%) and Eimeria alijevi (20.5%) being the most frequent species followed by Eimeria caprina (9.1%), Eimeria christenseni (4.5%), Eimeria jolchijevi (3.4%), Eimeria caprovina (3.2%) and Eimeria hirci (0.7%). Although significant differences were observed among goat groups and herds, the eight species were present in the six farms in both dairy goats and kids. The intensity of oocysts shedding was related to some factors such as the size of the herd and was further influenced by the prevailing climatic conditions of the area. The highest OPG counts were recorded during the hot season in dairy goats and close to weaning time in kids reared in small farms having no prophylactic treatments against eimeriosis.

Animals↗
PubMed2004

Thomsen-Friedenreich antigen expression in gastric carcinomas is associated with MUC1 mucin VNTR polymorphism.

Aberrant glycosylation of mucins is a common phenomenon associated with oncogenic transformation. We investigated the association between expression of the tumor-associated antigens T, Tn, and sialyl-Tn and polymorphism in the length of the MUC1 mucin tandem repeat in a series of gastric carcinomas. We further evaluated the relevance of MUC1 tandem repeat length on the expression of these tumor-associated carbohydrate antigens (TACAs) using a gastric carcinoma cell line model expressing recombinant MUC1 constructs carrying 0, 3, 9, and 42 repeats. Gastric carcinomas showed a high prevalence of Tn and sialyl-Tn antigens, whereas T antigen was less frequently expressed. The expression of T antigen was significantly higher in gastric carcinomas from patients homozygous for MUC1 large tandem repeat alleles. No significant associations were found for Tn and sialyl-Tn antigens. This novel association was reinforced by the gastric carcinoma cell line model experiments, where de novo expression of T antigen was detected in clones transfected with larger VNTR regions. Our results indicate that polymorphism in the MUC1 tandem repeat influences the expression of TACAs in gastric cancer cells and may therefore allow the identification of subgroups of patients that develop more aggressive tumors expressing T antigen.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed2001

MUC1 gene polymorphism in the gastric carcinogenesis pathway.

MUC1 like most mucin genes shows extensive length polymorphism in the central core region. In a previous study it was shown that individuals with small MUC1 alleles/genotypes have an increased risk for development of gastric carcinoma. Our aim was to see if MUC1 gene polymorphism was involved in susceptibility for the development of conditions that precede gastric carcinoma: chronic atrophic gastritis (CAG) and intestinal metaplasia (IM). We evaluated MUC1 polymorphism in a population of 174 individuals with chronic gastritis (CG) displaying (CAG) and/or intestinal metaplasia (IM). The population of patients with CG shows MUC1 allele frequencies significantly different from the gastric carcinoma patients and blood donors population. A significantly lower frequency of CAG and IM was observed in MUC1 VNTR heterozygotic patients. Within the group of patients with IM, MUC1 large VNTR homozygotes show a significantly higher frequency of complete IM while small VNTR homozygotes show a significantly higher frequency of incomplete IM. These findings show that MUC1 polymorphism may define different susceptibility backgrounds for the development of conditions that precede gastric carcinoma: chronic atrophic gastritis (CAG) and intestinal metaplasia (IM).

Adult↗
PubMed2000

Interferon beta1a therapy changes lipoprotein metabolism in patients with multiple sclerosis.

To assess whether interferon beta1a (IFNbeta1a) therapy affects plasma lipoprotein metabolism, twelve patients with relapsing-remitting multiple sclerosis (MS) were studied during a two-year follow-up period. High density lipoprotein (HDL2) cholesterol and the HDL2/HDL3 ratio were increased at year 2 and lipoprotein (a) was transitorily increased at year 1, in comparison to baseline levels. Apolipoprotein A-I was lower and apolipoprotein E higher at year 1, only in a subgroup of patients who experienced relapses and/or progressed during therapy. These findings suggest that IFNbeta1a treatment is associated with changes in the lipoprotein metabolism. Alterations in this metabolism could be related to the immunomodulatory actions of the drug and the disease activity in multiple sclerosis patients.

Adult↗
PubMed1999

Identification and characterization of large galactosyltransferase gene families: galactosyltransferases for all functions.

Enzymatic glycosylation of proteins and lipids is an abundant and important biological process. A great diversity of oligosaccharide structures and types of glycoconjugates is found in nature, and these are synthesized by a large number of glycosyltransferases. Glycosyltransferases have high donor and acceptor substrate specificities and are in general limited to catalysis of one unique glycosidic linkage. Emerging evidence indicates that formation of many glycosidic linkages is covered by large homologous glycosyltransferase gene families, and that the existence of multiple enzyme isoforms provides a degree of redundancy as well as a higher level of regulation of the glycoforms synthesized. Here, we discuss recent cloning strategies enabling the identification of these large glycosyltransferase gene families and exemplify the implication this has for our understanding of regulation of glycosylation by discussing two galactosyltransferase gene families.

Animals↗
PubMed1999

Cloning and expression of a proteoglycan UDP-galactose:beta-xylose beta1,4-galactosyltransferase I. A seventh member of the human beta4-galactosyltransferase gene family.

A seventh member of the human beta4-galactosyltransferase family, beta4Gal-T7, was identified by BLAST analysis of expressed sequence tags. The coding region of beta4Gal-T7 depicts a type II transmembrane protein with sequence similarity to beta4-galactosyltransferases, but the sequence was distinct in known motifs and did not contain the cysteine residues conserved in the other six members of the beta4Gal-T family. The genomic organization of beta4Gal-T7 was different from previous beta4Gal-Ts. Expression of beta4Gal-T7 in insect cells showed that the gene product had beta1,4-galactosyltransferase activity with beta-xylosides, and the linkage formed was Galbeta1-4Xyl. Thus, beta4Gal-T7 represents galactosyltransferase I enzyme (xylosylprotein beta1, 4-galactosyltransferase; EC 2.4.1.133), which attaches the first galactose in the proteoglycan linkage region GlcAbeta1-3Galbeta1-3Galbeta1-4Xylbeta1-O-Ser. Sequence analysis of beta4Gal-T7 from a fibroblast cell line of a patient with a progeroid syndrome and signs of the Ehlers-Danlos syndrome, previously shown to exhibit reduced galactosyltransferase I activity (Quentin, E., Gladen, A., Rodén, L., and Kresse, H. (1990) Proc. Natl. Acad. Sci. U. S. A. 87, 1342-1346), revealed two inherited allelic variants, beta4Gal-T7(186D) and beta4Gal-T7(206P), each with a single missense substitution in the putative catalytic domain of the enzyme. beta4Gal-T7(186D) exhibited a 4-fold elevated K(m) for the donor substrate, whereas essentially no activity was demonstrated with beta4Gal-T7(206P). Molecular cloning of beta4Gal-T7 should facilitate general studies of its pathogenic role in progeroid syndromes and connective tissue disorders with affected proteoglycan biosynthesis.

Amino Acid Sequence↗
PubMed1999

Interictal spike localization using a standard realistic head model: simulations and analysis of clinical data.

OBJECTIVES: In this paper realistic and standard realistic head models were applied to neural source localization. METHODS: Three different triangulated head structures; the brain, the skull and the scalp were constructed from MRI information of each patient. For each subject the exact positions of the electrodes were digitized. RESULTS: The influence of the number of triangles and of the skull conductivity on the accuracy of the method was tested. The use of a standard realistic head model instead of spherical models is proposed in cases where detailed MRI information is not available, and the accuracy of this procedure is tested with dipole simulations. These techniques were applied also to EEG signals from 3 patients with focal epilepsy. In all cases the neural activity was assumed to be confined to a small portion of cortical tissue, so that the neural generator was approximated to a current dipole. The realistic head model localization is discussed on the basis of neuroimaging information. CONCLUSIONS: We show that the standard realistic head model is two or 3 times better than the spherical model for dipole localization and we propose it as a good alternative to the spherical model for EEG data processing, in cases where full MRI information is not available.

Brain↗
PubMed1999

Randomized, double-blind study of stibogluconate plus human granulocyte macrophage colony-stimulating factor versus stibogluconate alone in the treatment of cutaneous Leishmaniasis.

The response to recombinant human granulocyte macrophage colony-stimulating factor (GM-CSF) in the treatment of cutaneous leishmaniasis was evaluated. Twenty patients with cutaneous leishmaniasis who had lesions for 60 days were enrolled in a double-blind placebo trial of GM-CSF with standard parenteral sodium stibogluconate (20 mg/kg-1/day-1) for 20 days. Ten patients were randomized to receive intralesionally injected GM-CSF (200 microgram) at enrollment and 1 week after, and 10 patients received saline as placebo. GM-CSF- and antimony-treated patients healed faster than patients who received antimony alone (49+/-32.8 vs. 110+/-61.6 days, P<.05). Seven of 10 patients were healed of their lesions before 40 days after therapy in the GM-CSF group, compared with only 1 of 10 patients in the placebo group (relative risk, 7; 95% confidence interval, 1.04-47.00). Thus, GM-CSF plus antimony significantly increased the chance of lesion healing in 40 days.

Adolescent↗
PubMed1999

Efforts to incorporate social justice perspectives into a family training program.

This paper describes the efforts of the faculty of the Family Institute of New Jersey in recent years to develop a collaborative family training program that takes into account issues of gender, race, culture, class, and sexual orientation. We have come to realize how strongly traditional approaches have been skewed in the direction of the dominant culture--white, male, heterosexist, and prioritizing the needs and experience of the middle and upper classes. We have attempted to modify our teaching, supervision, reading lists, and overall training approach to challenge trainees and ourselves to move toward broader, strength-based, and equity-based multicultural perspectives in our training. We describe our vision, how we incorporate it into our program structure, and a few of our training initiatives.

Adult↗
PubMed1998

Synthesis of poly-N-acetyllactosamine in core 2 branched O-glycans. The requirement of novel beta-1,4-galactosyltransferase IV and beta-1,3-n-acetylglucosaminyltransferase.

Poly-N-acetyllactosamine is a unique carbohydrate composed of N-acetyllactosamine repeats and provides the backbone structure for additional modifications such as sialyl Lex. Poly-N-acetyllactosamines in mucin-type O-glycans can be formed in core 2 branched oligosaccharides, which are synthesized by core 2 beta-1,6-N-acetylglucosaminyltransferase. Using a beta-1, 4-galactosyltransferase (beta4Gal-TI) present in milk and the recently cloned beta-1,3-N-acetylglucosaminyltransferase, the formation of poly-N-acetyllactosamine was found to be extremely inefficient starting from a core 2 branched oligosaccharide, GlcNAcbeta1-->6(Galbeta1-->3)GalNAcalpha-->R. Since the majority of synthesized oligosaccharides contained N-acetylglucosamine at the nonreducing ends, galactosylation was judged to be inefficient, prompting us to test novel members of the beta4Gal-T gene family for this synthesis. Using various synthetic acceptors and recombinant beta4Gal-Ts, beta4Gal-TIV was found to be most efficient in the addition of a single galactose residue to GlcNAcbeta1-->6(Galbeta1-->3)GalNAcalpha-->R. Moreover, beta4Gal-TIV, together with beta-1,3-N-acetylglucosaminyltransferase, was capable of synthesizing poly-N-acetyllactosamine in core 2 branched oligosaccharides. On the other hand, beta4Gal-TI was found to be most efficient for poly-N-acetyllactosamine synthesis in N-glycans. In contrast to beta4Gal-TI, the efficiency of beta4Gal-TIV decreased dramatically as the acceptors contained more N-acetyllactosamine repeats, consistent with the fact that core 2 branched O-glycans contain fewer and shorter poly-N-acetyllactosamines than N-glycans in many cells. These results, as a whole, indicate that beta4Gal-TIV is responsible for poly-N-acetyllactosamine synthesis in core 2 branched O-glycans.

Animals↗
PubMed1998

Cloning of a novel member of the UDP-galactose:beta-N-acetylglucosamine beta1,4-galactosyltransferase family, beta4Gal-T4, involved in glycosphingolipid biosynthesis.

A novel putative member of the human UDP-galactose:beta-N-acetylglucosamine beta1,4-galactosyltransferase family, designated beta4Gal-T4, was identified by BLAST analysis of expressed sequence tags. The sequence of beta4Gal-T4 encoded a type II membrane protein with significant sequence similarity to other beta1,4-galactosyltransferases. Expression of the full coding sequence and a secreted form of beta4Gal-T4 in insect cells showed that the gene product had beta1,4-galactosyltransferase activity. Analysis of the substrate specificity of the secreted form revealed that the enzyme catalyzed glycosylation of glycolipids with terminal beta-GlcNAc; however, in contrast to beta4Gal-T1, -T2, and -T3, this enzyme did not transfer galactose to asialo-agalacto-fetuin, asialo-agalacto-transferrin, or ovalbumin. The catalytic activity of beta4Gal-T4 with monosaccharide acceptor substrates, N-acetylglucosamine as well as glucose, was markedly activated in the presence of alpha-lactalbumin. The genomic organization of the coding region of beta4Gal-T4 was contained in six exons. All intron/exon boundaries were similarly positioned in beta4Gal-T1, -T2, and -T3. beta4Gal-T4 represents a new member of the beta4-galactosyltransferase family. Its kinetic parameters suggest unique functions in the synthesis of neolactoseries glycosphingolipids.

Amino Acid Sequence↗
PubMed1998

A family of human beta3-galactosyltransferases. Characterization of four members of a UDP-galactose:beta-N-acetyl-glucosamine/beta-nacetyl-galactosamine beta-1,3-galactosyltransferase family.

BLAST analysis of expressed sequence tags (ESTs) using the coding sequence of a human UDP-galactose:beta-N-acetyl-glucosamine beta-1, 3-galactosyltransferase, designated beta3Gal-T1, revealed no ESTs with identical sequences but a large number with similarity. Three different sets of overlapping ESTs with sequence similarities to beta3Gal-T1 were compiled, and complete coding regions of these genes were obtained. Expression of two of these genes in the Baculo virus system showed that one represented a UDP-galactose:beta-N-acetyl-glucosamine beta-1, 3-galactosyltransferase (beta3Gal-T2) with similar kinetic properties as beta3Gal-T1. Another gene represented a UDP-galactose:beta-N-acetyl-galactosamine beta-1, 3-galactosyltransferase (beta3Gal-T4) involved in GM1/GD1 ganglioside synthesis, and this gene was highly similar to a recently reported rat GD1 synthase (Miyazaki, H., Fukumoto, S., Okada, M., Hasegawa, T., and Furukawa, K. (1997) J. Biol. Chem. 272, 24794-24799). Northern analysis of mRNA from human organs with the four homologous cDNA revealed different expression patterns. beta3Gal-T1 mRNA was expressed in brain, beta3Gal-T2 was expressed in brain and heart, and beta3Gal-T3 and -T4 were more widely expressed. The coding regions for each of the four genes were contained in single exons. beta3Gal-T2, -T3, and -T4 were localized to 1q31, 3q25, and 6p21.3, respectively, by EST mapping. The results demonstrate the existence of a family of homologous beta3-galactosyltransferase genes.

Amino Acid Sequence↗
PubMed1998

[Partial median sternotomy in H. A new approach for cardiac surgery].

PURPOSE: To present our results with the minimally invasive thoracotomy (MIT) in patients with valve disease and to describe a new type of thoracotomy. METHODS: Twenty-five patients with valve disease as the major cardiac problem were operated during a five month period. Two types of incisions were used: one in an inverted-T fashion and another in a H fashion. Fourteen patients were submitted to an inverted-T incision and eleven to a H incision. In 24% of the patients reoperation was being performed. RESULTS: The incisions ranged from 7.5 to 11 cm (mean 9.1 cm), mean ICU stay was 31 h and hospital stay 4.8 days. In all but one patient the operation could be adequately in performed through the MIT, in only one patient total sternotomy had to be performed. CONCLUSION: The MIT may have some advantages such as, better aesthetic results, less pain and more sternal stability. These factors may improve early extubation and decrease hospital stay. The H type incision allows an adequate exposition of the most central part of the chest and all heart valves with adequate exposure. This technique led to no complications during reoperations and we believe it to be as safe as the total sternotomy.

Adolescent↗
PubMed1997

A family of human beta4-galactosyltransferases. Cloning and expression of two novel UDP-galactose:beta-n-acetylglucosamine beta1, 4-galactosyltransferases, beta4Gal-T2 and beta4Gal-T3.

BLAST analysis of expressed sequence tags (ESTs) using the coding sequence of the human UDP-galactose:beta-N-acetylglucosamine beta1, 4-galactosyltransferase, designated beta4Gal-T1, revealed a large number of ESTs with identical as well as similar sequences. ESTs with sequences similar to that of beta4Gal-T1 could be grouped into at least two non-identical sequence sets. Analysis of the predicted amino acid sequence of the novel ESTs with beta4Gal-T1 revealed conservation of short sequence motifs as well as cysteine residues previously shown to be important for the function of beta4Gal-T1. The likelihood that the identified ESTs represented novel galactosyltransferase genes was tested by cloning and sequencing of the full coding region of two distinct genes, followed by expression. Expression of soluble secreted constructs in the baculovirus system showed that these genes represented genuine UDP-galactose:beta-N-acetylglucosamine beta1, 4-galactosyltransferases, thus designated beta4Gal-T2 and beta4Gal-T3. Genomic cloning of the genes revealed that they have identical genomic organizations compared with beta4Gal-T1. The two novel genes were located on 1p32-33 and 1q23. The results demonstrate the existence of a family of homologous galactosyltransferases with related functions. The existence of multiple beta4-galactosyltransferases with the same or overlapping functions may be relevant for interpretation of biological functions previously assigned to beta4Gal-T1.

Amino Acid Sequence↗
PubMed1996

APC intragenic haplotypes in familial adenomatous polyposis.

Genetic epidemiological studies are useful for the knowledge of the association of markers and genes involved in diseases. In the present work, we studied the frequency of four adenomatous polyposis coli intragenic RFLP markers often used in risk evaluation in a population of 10 familial adenomatous polyposis patients from 10 unrelated Portuguese familial adenomatous polyposis families not sharing the same mutation, and in a population of 55 unrelated healthy Portuguese volunteers. We compared the frequency obtained to normal and affected populations and to results already reported in other populations. We observed allelic frequencies for the Portuguese population that agree with the published ones. The intragenic polymorphisms show strong gametic disequilibrium suggesting little recombination between them. We observed haplotype frequencies significantly different in patients and controls. The gametic disequilibrium may be due to a common founder for a proportion of apparently unrelated probands.

Adenomatous Polyposis Coli↗
PubMed1996

Presymptomatic diagnosis in Portuguese FAP families using intragenic RFLPs and (CA)n flanking markers by fluorescence based semiautomated DNA analysis.

Owing to the large size of the APC gene, responsible for familial adenomatous polyposis, direct screening for individual mutations is not a practical approach. In the present study we establish the methodology of fluorescence based semi-automated DNA analysis to perform presymptomatic diagnosis of members at risk from 11 Portuguese FAP families with three (CA)n markers flanking the APC gene, MBC, CB26, and YN5.64, and four intragenic RFLPs. Haplotypes were constructed on the basis of individual genotypes and their segregation through generations were followed. The study was informative for 12% of subjects using only intragenic RFLPs and increased to 90% when we used the three (CA)n flanking markers. We report two of the 11 families under study in our laboratory and show recombinant events leading to a precise localisation of the CB26 marker between D5S82 and the APC gene. In one family there was a loss of (CA) units of one allele of the CB26 marker from an unaffected mother to her son.

Adenomatous Polyposis Coli↗