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Biomedical subjects

M A Moreira

Publications and source records attributed to M A Moreira.

At least 37 records · Page 2Linked to original sources
PubMed1999

Phylogenetic relationships of the Callitrichinae (Platyrrhini, primates) based on beta2-microglobulin DNA sequences.

The phylogenetic relationships of callitrichine primates have been determined by DNA sequence analyses of exons 1, 2, and 3 of the beta2-microglobulin gene. Parsimony, distance, and maximum likelihood analyses of ca. 900 base pairs of 21 taxa, representing all callitrichine genera, indicated that Saguinus was the most basal offshoot. Within Saguinus, S. fuscicollis appeared as the first divergent lineage followed by an unresolved trichotomy formed by S. mystax/S. imperator, S. midas/S. bicolor, and S. oedipus. A second callitrichine lineage was formed by Leontopithecus; each of the three species studied showed identical nucleotide sequences. Callimico appeared as the sister taxon of Callithrix/Cebuella. Genetic distances within this latter group were very small, although a stronger association between Cebuella and species of the Callithrix argentata group was observed. The inclusion of Cebuella in the genus Callithrix is suggested. These studies indicated that tamarins are more plesiomorphic than marmosets in agreement with the phyletic dwarfism hypothesis.

Animals↗
PubMed1999

Molecular phylogeny of new world primates (Platyrrhini) based on beta2-microglobulin DNA sequences.

Neotropical primates, traditionally grouped in the infraorder Platyrrhini, comprise 16 extant genera. Cladistic analyses based on morphological characteristics and molecular data resulted in topologic arrangements depicting disparate phylogenetic relationships, indicating that the evolution of gross morphological characteristics and molecular traits is not necessarily congruent. Here we present a phylogenetic arrangement for all neotropical primate genera obtained from DNA sequence analyses of the beta2-microglobulin gene. Parsimony, distance, and maximum likelihood analyses favored two families, Atelidae and Cebidae, each containing 8 genera. Atelids were resolved into atelines and pitheciines. The well-supported ateline clade branched into alouattine (Alouatta) and ateline (Ateles, Lagothrix, Brachyteles) clades. In turn, within the Ateline clade, Lagothrix and Brachyteles were well-supported sister groups. The pitheciines branched into well-supported callicebine (Callicebus) and pitheciine (Pithecia, Cacajao, Chiropotes) clades. In turn, within the pitheciine clade, Cacajao and Chiropotes were well-supported sister groups. The cebids branched into callitrichine (Saguinus, Leontopithecus, Callimico, Callithrix-Cebuella), cebine (Cebus, Saimiri), and aotine (Aotus) clades. While the callitrichine clade and the groupings of species and genera within this clade were all well supported, the cebine clade received only modest support, and the position of Aotus could not be clearly established. Cladistic analyses favored the proposition of 15 rather than 16 extant genera by including Cebuella pygmaea in the genus Callithrix as the sister group of the Callithrix argentata species group. These analyses also favored the sister grouping of Callimico with Callithrix and then of Leontopithecus with the Callithrix-Callimico clade.

Animals↗
PubMed1999

Disparate phylogeographic patterns of molecular genetic variation in four closely related South American small cat species.

Tissue specimens from four species of Neotropical small cats (Oncifelis geoffroyi, N = 38; O. guigna, N = 6; Leopardus tigrinus, N = 32; Lynchailurus colocolo, N = 22) collected from throughout their distribution were examined for patterns of DNA sequence variation using three mitochondrial genes, 16S rRNA, ATP8, and NADH-5. Patterns between and among O. guigna and O. geoffroyi individuals were assessed further from size variation at 20 microsatellite loci. Phylogenetic analyses using mitochondrial DNA sequences revealed monophyletic clustering of the four species, plus evidence of natural hybridization between L. tigrinus and L. colocolo in areas of range overlap and discrete population subdivisions reflecting geographical isolation. Several commonly accepted subspecies partitions were affirmed for L. colocolo, but not for O. geoffroyi. The lack of geographical substructure in O. geoffroyi was recapitulated with the microsatellite data, as was the monophyletic clustering of O. guigna and O. geoffroyi individuals. L. tigrinus forms two phylogeographic clusters which correspond to L.t. oncilla (from Costa Rica) and L.t. guttula (from Brazil) and which have mitochondrial DNA (mtDNA) genetic distance estimates comparable to interspecific values between other ocelot lineage species. Using feline-specific calibration rates for mitochondrial DNA mutation rates, we estimated that extant lineages of O. guigna diverged 0.4 million years ago (Ma), compared with 1.7 Ma for L. colocolo, 2.0 Ma for O. geoffroyi, and 3.7 Ma for L. tigrinus.

Alleles↗
PubMed1999

Evolutionary disruptions of human syntenic groups 3, 12, 14, and 15 in Ateles paniscus chamek (Platyrrhini, primates).

Comparative gene assignments of 18 markers, based on analyses of somatic cell hybrids and previous data in the literature, indicated that human (HSA) syntenic groups 3, 12, 14, and 15 are dissociated in the spider monkey species Ateles paniscus chamek (APC). Markers present in HSA 3p were allocated to APC 3 and APC 9. The HSA 12 cluster was split into two syntenic groups, one mainly including HSA 12p markers in APC 16 and the other, including HSA 12q markers, in APC 2p. The HSA 14q cluster split into three syntenic groups, corresponding to APC 2q, APC 6, and APC 12. Finally, the HSA 15 cluster split into two syntenic groups, APC 2q and APC 3. Comparisons with previous gene assignments and human SROs led to the tentative postulation of rearrangements having occurred during the evolutionary divergence of man and A. paniscus chamek. Chromosome painting data in the congeneric species A. geoffroyi, other New World and Old World primates, and several representative non-primate animals were compared in an attempt to delineate the ancestral and derived conditions underlying the evolutionary rearrangement of syntenic groups in mammals.

Animals↗
PubMed1998

Comparative gene assignment in Ateles paniscus chamek (Platyrrhini, Primates) and man: association of three separate human syntenic groups and evolutionary considerations.

Regional assignment of eight markers to chromosome 2 of Ateles paniscus chamek (APC) confirmed a syntenic association similar to human (HSA) 12q + 14q + 15q. Three HSA 12q markers (RAP1B, PAH and ALDH2) were allocated to a shortest region of overlap (SRO) in APC 2p and found to be syntenic to other HSA 12q markers (PEPB and TCF1). Five HSA 14q markers (CTLA, PAX9, NSP, FOS and CHGA) were allocated to APC 2q and found to be syntenic to other HSA 14q markers (NP, TGM1, and CALM1) and to four HSA 15q markers (THBS1, B2M, HEXA and MPI) but dissociated from markers close to HSA 14qter (CKB) and HSA 15qter (FES-IDH2). Karyotypic comparisons showed an evident homoeology between APC 2p and HSA 12q while APC 2q was similar to an HSA 14qter::HSA 15qter fusion product. Comparative gene mapping data show that the HSA 14q + HSA 15q syntenic association is an ancestral mammalian gene cluster that has been maintained in several primate taxa. Conversely, in Ateles, it has been further associated with HSA 12q while, in Hominoids and Cebus, it has been independently dissociated into two separate syntenic groups, similar to HSA 14q and HSA 15q.

Animals↗
PubMed1997

The human chromosome 3 gene cluster ACY1-CACNA1D-ZNF64-ATP2B2 is evolutionarily conserved in Ateles paniscus chamek (Platyrrhini, Primates).

Comparative mapping of Ateles paniscus chamek and man indicated that four human 3p markers are syntenic in this karyotypically rearranged neotropical primate. The evolutionary conservation of this gene cluster includes three adjacent human shortest regions of overlap (SROs): 3p21.1 (ACY1), 3p21.3-->p21.2 (CACNA1D), and 3p21.3 (ZNF64). A fourth syntenic marker (ATP2B2), at a more distal human SRO (3p26-->p25), indicated that human 3pter-->p14 is evolutionarily conserved in Ateles chromosome 3 (APC 3). Conversely, allocations of two human 3q markers (AGTR1 and IL12A) clearly excluded APC 3. Finally, allocation of the major histocompatibility complex class I genes further confirmed human 6p-6q dissociations in Ateles.

Animals↗
PubMed1997

Assignment of TCF1, TGM1, CALM1, CKB, THBS1, B2M, and FES in Ateles paniscus chamek (Platyrrhini, Primates).

Regional assignment of five markers to chromosome 2 of Ateles paniscus chamek (APC) confirmed a syntenic association similar to human (HSA) 12q + 14q + 15q. TCF1 was allocated to a shortest region of overlap (SRO) in APC 2p and found to be syntenic to PEPB, while TGM1, CALM1, THBS1, and B2M were assigned to APC 2q, being syntenic to NP, HEXA, and MPI. Conversely, markers close to HSA 14qter (CKB) and HSA 15qter (FES-IDH2) were relocated to other Ateles syntenic groups. Karyotypic comparisons showed an evident homoeology between APC 2p and HSA 12q, whereas APC 2q was similar to an HSA 14qter::HSA 15qter fusion product.

Animals↗
PubMed1993

Risk of complication in perforated duodenal ulcer operations according to the surgical technique employed.

We prospectively analyzed a homogeneous group of 65 patients with perforated duodenal ulcer whose medical condition (no perioperative shock, no associated disease, underwent laparotomy within 12 hours after perforation, and an APACHE II score below 11) would have little effect on the outcome of surgery to study the influence of the surgical procedure (suture closure, vagotomy, or gastrectomy) on the morbidity and mortality rate. Thirty-three patients (51%) underwent vagotomy, 25 (38%) simple suture closure, and seven (11%) gastrectomy. Five patients (8%) suffered postoperative complications, two (3%) required further operation, and one (1.5%) died of pulmonary sepsis. Statistical analyses revealed that "vagotomy" presented significantly better results than did "simple suture" and "gastrectomy" that had similar results. The type of surgery, however, was not a significant risk factor in predicting complications in this sample. This study points out the need to stratify the perforated duodenal ulcer patients for accurate investigations. It also shows that definitive operations (gastrectomy or vagotomy) do not increase surgical risk in this group of patients, and, considering the poorer results with simple suture closure compared to vagotomy, the latter is an attractive option because it also treats the underlying ulcer disease.

Adult↗
PubMed1990

Administration of thyrotropin-releasing hormone into the central nucleus of the amygdala induces gastric lesions in rats.

Studies utilizing microinjections of thyrotropin-releasing hormone (TRH) were performed to determine potentially sensitive limbic brain sites to the ulcerogenic effect of TRH. Administration of TRH into the central nucleus of the amygdala (CEA) produced a high (80%) incidence of gastric lesions and also significantly stimulated acid secretion. Microinjections of TRH into other brain sites including superior colliculus, medial septum, substantia nigra and the hippocampus (CA1 area) were ineffective. Intra-CEA TRH-induced gastric lesions and acid secretion were prevented by vagotomy. These results indicate that the amygdala is of importance for mediating the ulcerogenic effect of brain TRH through peripheral vagal pathways.

Amygdala↗
PubMed1990

Brain ACTH prevents stress gastric lesions in rats.

This study evaluated the effect of ACTH and several ACTH fragments on the development of gastric glandular lesions induced by cold-restraint stress in rats. Intracerebroventricular administration of ACTH1-39 dose-dependently (0.1-10 micrograms) inhibited stress gastric lesion formation. Studies with smaller molecular weight forms of ACTH (in a dose equimolar to 10 micrograms of ACTH1-39) revealed that ACTH1-13 and ACTH1-10 were also protective. The ACTH fragments ACTH5-10, ACTH34-39 and ACTH1-17 were without effect. Immunoneutralization of endogenous brain ACTH1-39 significantly increased stress gastric lesion severity. Antisera raised against synthetic somatostatin, gonadotropin-releasing hormone, and L-enkephalin were ineffective. These results with ACTH coupled with our previous demonstration of a protective effect of beta-endorphin suggest that specific brain pro-opiomelanocortin gene products modulate gastric mucosal integrity in response to stress.

Adrenocorticotropic Hormone↗
PubMed1989

A procedure to obtain long-lasting fluorescence in formaldehyde fixed tissues.

The authors made a study of the small intestine by immunofluorescence in 5% phosphate-buffered formaldehyde fixed tissues, using the Nairn (1976) technique associated with Evans blue (Fry and Wilkinson 1963). The ability of the sections to fluoresce has been maintained after a storage time of more than 4 years. Similar very good results were obtained when skin biopsies from pemphigus foliaceus patients were fixed in formaldehyde for two h and afterwards washed in 30% sucrose solution for 12 to 18 h.

Biopsy↗
PubMed1989

Morphometric quantification of plasma cells in the intestinal mucosa of children. A comparative study between two sampling procedures.

In an attempt to obtain a sampling procedure of known accuracy for plasma cell quantification, applicable for routine analysis, we counted IgA, IgM and IgG producing cells in the lamina propria of the small intestine of six children by the method II of Aherne (1976), using two sampling procedures. In the first, we determined the number of cells in each one of 200 successive microscopic fields without specifying their localization in the mucosa. Proper tests upon this data showed that in order to estimate the number of IgA producing cells per mm3 of lamina propria with a confidence of 95% that the mean of the sample would not differ by more than 5% from the mean of the population, it would be necessary to count 850-900 microscopic fields. With a confidence of 90% that the two means cited will not differ between them by more than 10%, the number of fields to be counted would lie in the range of 150 to 200. In the second procedure we arbitrarily divided the mucosa into upper, middle and lower segments, identifying and counting the number of cells in each segment. Consistent results for the number of IgA, IgM and IgG-containing cells were obtained by averaging the data of sufficient number of counts of 30 fields: 10 in the upper segment, 10 in the middle segment and 10 in the lower segment. Means obtained by stratified counts of IgA producing cells in 60 microscopic fields, 20 in each segment, differed, in 93% of the samples, by no more than 10% from the mean derived from the counts of 200 successive fields. Stratified sampling also enabled us to detect a segmental variation which had not thus far been quantified. In all cases, it was observed that the numerical concentration of IgA producing cells was greater in the lower region than in the middle zone, while for both IgM and IgG cells the larger numbers occurred in the middle and lower segments. The lowest concentration of IgA, IgM and IgG cells occurred at the top of the villi.

Child↗
PubMed1979

Partial characterization of the acidic and basic polypeptides of glycinin.

The subunits of the 11 S storage protein from soybean cultivar CX635-1-1-1 were purified and characterized. Six polypeptides with acidic isoelectric points and four with basic isoelectric points were isolated from the purified storage protein. The acidic polypeptides had phenylalanine, leucine, isoleucine, and arginine at the NH2 termini, while the basic polypeptides all had glycine at the NH2 termini. Amino acid analysis indicated that certain acidic and basic polypeptides contained 3 to 6 times more methionine than the other polypeptides. Since the low nutritional quality of legume storage proteins is due to a deficiency in methionine, this observation will have significance in efforts to improve soybean quality. The purified polypeptides were further characterized by NH2-terminal sequence analysis. Considerable homology was found between the members of individual families of acidic and basic polypeptides, indicating that the members of each family arose from a common ancestral gene. This study showed that the glycinin polypeptide composition is more complex than previous reports indicated, and for the first time characterized the various polypeptides of the 11 S storage protein by structural analysis.

Amino Acid Sequence↗