RESUMO
BACKGROUND: The Micronycterinae form a subfamily of leaf-nosed bats (Phyllostomidae) that contains the genera Lampronycteris Sanborn, 1949, and Micronycteris Gray, 1866 (stricto sensu), and is characterized by marked karyotypic variability and discrepancies in the phylogenetic relationships suggested by the molecular versus morphological data. In the present study, we investigated the chromosomal evolution of the Micronycterinae using classical cytogenetics and multidirectional chromosome painting with whole-chromosomes probes of Phyllostomus hastatus and Carollia brevicauda. Our goal was to perform comparative chromosome mapping between the genera of this subfamily and explore the potential for using chromosomal rearrangements as phylogenetic markers. RESULTS: The Micronycterinae exhibit great inter- and intraspecific karyotype diversity, with large blocks of telomere-like sequences inserted within or adjacent to constitutive heterochromatin regions. The phylogenetic results generated from our chromosomal data revealed that the Micronycterinae hold a basal position in the phylogenetic tree of the Phyllostomidae. Molecular cytogenetic data confirmed that there is a low degree of karyotype similarity between Lampronycteris and Micronycteris specimens analyzed, indicating an absence of synapomorphic associations in Micronycterinae. CONCLUSIONS: We herein confirm that karyotypic variability is present in subfamily Micronycterinae. We further report intraspecific variation and describe a new cytotype in M. megalotis. The cytogenetic data show that this group typically has large blocks of interstitial telomeric sequences that do not appear to be correlated with chromosomal rearrangement events. Phylogenetic analysis using chromosome data recovered the basal position for Micronycterinae, but did not demonstrate that it is a monophyletic lineage, due to the absence of common chromosomal synapomorphy between the genera. These findings may be related to an increase in the rate of chromosomal evolution during the time period that separates Lampronycteris from Micronycteris.
Assuntos
Quirópteros/classificação , Quirópteros/genética , Evolução Molecular , Cariótipo , Filogenia , Animais , Teorema de Bayes , Mapeamento Cromossômico , Coloração Cromossômica/métodos , Cromossomos de Mamíferos/genéticaRESUMO
Anoles are a clade of iguanian lizards that underwent an extensive radiation between 125 and 65 million years ago. Their karyotypes show wide variation in diploid number spanning from 26 (Anolis evermanni) to 44 (A. insolitus). This chromosomal variation involves their sex chromosomes, ranging from simple systems (XX/XY), with heterochromosomes represented by either micro- or macrochromosomes, to multiple systems (X1X1X2X2/X1X2Y). Here, for the first time, the homology relationships of sex chromosomes have been investigated in nine anole lizards at the whole chromosome level. Cross-species chromosome painting using sex chromosome paints from A. carolinensis, Ctenonotus pogus and Norops sagrei and gene mapping of X-linked genes demonstrated that the anole ancestral sex chromosome system constituted by microchromosomes is retained in all the species with the ancestral karyotype (2n = 36, 12 macro- and 24 microchromosomes). On the contrary, species with a derived karyotype, namely those belonging to genera Ctenonotus and Norops, show a series of rearrangements (fusions/fissions) involving autosomes/microchromosomes that led to the formation of their current sex chromosome systems. These results demonstrate that different autosomes were involved in translocations with sex chromosomes in closely related lineages of anole lizards and that several sequential microautosome/sex chromosome fusions lead to a remarkable increase in size of Norops sagrei sex chromosomes.
Assuntos
Evolução Molecular , Lagartos/genética , Cromossomos Sexuais , Animais , Bandeamento Cromossômico , Mapeamento Cromossômico , Coloração Cromossômica , Feminino , Genes Mitocondriais , Hibridização in Situ Fluorescente , Cariótipo , Cariotipagem , Masculino , Recombinação GenéticaRESUMO
The species of genera Uroderma and Artibeus are medium-sized bats belonging to the family Phyllostomidae and subfamily Stenodermatinae (Mammalia, Chiroptera) from South America. They have a wide distribution in the Neotropical region, with two currently recognized species in Uroderma and approximately 20 species in Artibeus. These two genera have different rates of chromosome evolution, with Artibeus probably having retained the ancestral karyotype for the subfamily. We used whole chromosome paint probe sets from Carollia brevicauda and Phyllostomus hastatus on Uroderma magnirostrum, Uroderma bilobatum, and Artibeus obscurus. With the aim of testing the previous phylogenies of these bats using cytogenetics, we compared these results with published painting maps on Phyllostomidae. The genome-wide comparative maps based on chromosome painting and chromosome banding reveal the chromosome forms that characterize each taxonomic level within the Phyllostomidae and show the chromosome evolution of this family. Based on this, we are able to suggest an ancestral karyotype for Phyllostomidae. Our cladistic analysis is an independent confirmation using multidirectional chromosome painting of the previous Phyllostomidae phylogenies.
Assuntos
Quirópteros/classificação , Quirópteros/genética , Coloração Cromossômica/métodos , Filogenia , Animais , Bandeamento Cromossômico , Mapeamento Cromossômico , Cromossomos/genética , Evolução Molecular , Cariotipagem/métodos , América do Sul , Especificidade da Espécie , Translocação GenéticaRESUMO
The genus Gymnotus (Gymnotiformes) is a group of fishes with karyotypic plasticity, demonstrated by cytogenetic studies using whole chromosome probes of G. carapo (GCA, 2n = 42) that were obtained by flow-sorting from fibroblast cultures. In the present work we undertook comparative mapping of the karyotype of G. capanema (GCP, 2n = 34) with GCA, 2n = 42 painting probes. The results demonstrate that the karyotype of G. capanema is extensively rearranged when compared to G. carapo. From the 12 chromosome pairs of G. carapo that can be individually differentiated (GCA1-3, 6, 7, 9, 14, 16 and 18-21), only 4 pairs (GCA6, 7, 19, and 20) maintained conserved synteny in G. capanema. From these 4, GCA6 and GCA20 correspond to individual chromosomes (GCP8 and GCP15), while the other 2 share homology with parts of GCP1 and GCP2, respectively. The remaining GCP chromosomes showed more complex hybridization patterns with homologies to other GCA pairs. These results demonstrate that the level of reorganization in the genome of G. capanema is much greater than in GCA, 2n = 42 and in karyomorph GCA, 2n = 40 which was previously analyzed by chromosome painting.
Assuntos
Gimnotiformes/genética , Animais , Coloração Cromossômica , Cromossomos/genética , Feminino , Cariotipagem , MasculinoRESUMO
We report extensive chromosome homology revealed by chromosome painting between chicken (Gallus gallus domesticus, GGA, 2n = 78) macrochromosomes (representing 70% of the chicken genome) and the chromosomes of a turtle, the red-eared slider (Trachemys scripta elegans, TSC, 2n = 50), and the Nile crocodile (Crocodylus niloticus, CNI, 2n = 32). Our data show that GGA1-8 arms seem to be conserved in the arms of TSC chromosomes, GGA1-2 arms are separated and homologous to CNI1p, 3q, 4q and 5q. In addition to GGAZ homologues in our previous study, large-scale GGA autosome syntenies have been conserved in turtle and crocodile despite hundreds of millions of years divergence time. Based on phylogenetic hypotheses that crocodiles diverged after the divergence of birds and turtles, our results in CNI suggest that GGA1-2 and TSC1-2 represent the ancestral state and that chromosome fissions followed by fusions have been the mechanisms responsible for the reduction of chromosome number in crocodiles.
Assuntos
Jacarés e Crocodilos/genética , Galinhas/genética , Tartarugas/genética , Jacarés e Crocodilos/classificação , Animais , Galinhas/classificação , Coloração Cromossômica , Evolução Molecular , Cariotipagem , Filogenia , Especificidade da Espécie , Fatores de Tempo , Tartarugas/classificaçãoRESUMO
Substantial effort has been made to elucidate karyotypic evolution of phyllostomid bats, mostly through comparisons of G-banding patterns. However, due to the limited number of G-bands in respective karyotypes and to the similarity of non-homologous bands, an accurate evolutionary history of chromosome segments remains questionable. This is the case for vampire bats (Desmodontinae). Despite several proposed homologies, banding data have not yet provided a detailed understanding of the chromosomal changes within vampire genera. We examined karyotype differentiation of the 3 species within this subfamily using whole chromosomal probes from Phyllostomus hastatus (Phyllostominae) and Carollia brevicauda (Carolliinae). Painting probes of P. hastatus respectively detected 22, 21 and 23 conserved segments in Diphylla ecaudata, Diaemus youngi, and Desmodus rotundus karyotypes, whereas 27, 27 and 28 were respectively detectedwith C. brevicauda paints. Based on the evolutionary relationships proposed by morphological and molecular data, we present probable chromosomal synapomorphies for vampire bats and propose chromosomes that were present in the common ancestor of the 5 genera analyzed. Karyotype comparisons allowed us to relate a number of conserved chromosomal segments among the 5 species, providing a broader database for understanding karyotype evolution in the family.
Assuntos
Quirópteros/genética , Coloração Cromossômica/métodos , Animais , Quirópteros/classificação , Bandeamento Cromossômico , Cariotipagem , Filogenia , Especificidade da Espécie , SinteniaRESUMO
By suppressing recombination and reducing gene flow, chromosome inversions favor the capture and protection of advantageous allelic combinations, leading to adaptive polymorphisms. However, studies in non-model species remain scarce. Here we investigate the distribution of inversion polymorphisms in the multimammate rat Mastomys erythroleucus in West Africa. More than 270 individuals from 52 localities were karyotyped using G-bands and showed widespread polymorphisms involving four chromosome pairs. No significant deviations from Hardy-Weinberg equilibrium were observed either through space or time, nor were differences retrieved in viability or sex contribution between cytotypes. The distribution of chromosomal variation, however, showed perfect congruence with that of mtDNA-based phylogeographic clades. Thus, inversion diversity patterns in M. erythroleucus appeared more related to historical and/or demographic processes than to climate-based adaptive features. Using cross-species chromosome painting and G-banding analyses to identify homologous chromosomes in related out-group species, we proposed a phylogenetic scenario that involves ancestral-shared polymorphisms and subsequent lineage sorting during expansion/contraction of West African savannas. Our data suggest that long-standing inversion polymorphisms may act as regions in which adaptation genes may accumulate (nucleation model).
Assuntos
Inversão Cromossômica , Murinae/genética , Polimorfismo Genético , África Ocidental , Animais , Animais Selvagens/genética , Camarões , Chade , Inversão Cromossômica/genética , Coloração Cromossômica , Feminino , Frequência do Gene , Geografia , Masculino , FilogeniaRESUMO
BACKGROUND: Autism is a common childhood onset neurodevelopmental disorder, characterised by severe and sustained impairment of social interaction and social communication, as well as a notably restricted repertoire of activities and interests. Its aetiology is multifactorial with a strong genetic basis. EIF4E is the rate limiting component of eukaryotic translation initiation, and plays a key role in learning and memory through its control of translation within the synapse. EIF4E mediated translation is the final common process modulated by the mammalian target of rapamycin (mTOR), PTEN and fragile X mental retardation protein (FMRP) pathways, which are implicated in autism. Linkage of autism to the EIF4E region on chromosome 4q has been found in genome wide linkage studies. METHODS AND RESULTS: The authors present evidence that directly implicates EIF4E in autism. In a boy with classic autism, the authors observed a de novo chromosome translocation between 4q and 5q and mapped the breakpoint site to within a proposed alternative transcript of EIF4E. They then screened 120 autism families for mutations and found two unrelated families where in each case both autistic siblings and one of the parents harboured the same single nucleotide insertion at position -25 in the basal element of the EIF4E promoter. Electrophoretic mobility shift assays and reporter gene studies show that this mutation enhances binding of a nuclear factor and EIF4E promoter activity. CONCLUSIONS: These observations implicate EIF4E, and more specifically control of EIF4E activity, directly in autism. The findings raise the exciting possibility that pharmacological manipulation of EIF4E may provide therapeutic benefit for those with autism caused by disturbance of the converging pathways controlling EIF4E activity.
Assuntos
Transtorno Autístico/genética , Fator de Iniciação 4E em Eucariotos/genética , Regulação da Expressão Gênica , Transtorno Autístico/metabolismo , Sequência de Bases , Encéfalo/metabolismo , Linhagem Celular , Pré-Escolar , Mapeamento Cromossômico , Análise Mutacional de DNA , Fator de Iniciação 4E em Eucariotos/biossíntese , Células HeLa , Humanos , Hibridização in Situ Fluorescente , Masculino , Dados de Sequência Molecular , Mutagênese Insercional , Mutação , Linhagem , Regiões Promotoras Genéticas , RNA Mensageiro/metabolismo , Alinhamento de Sequência , Translocação GenéticaRESUMO
Classical and molecular cytogenetic analyses of mitotic and meiotic cells were performed on two species of Carollia from the family Phyllostomidae (Chiroptera), which have an XX/XY(1)Y(2) sex determination system. Our results show that the species Carollia perspicillata and Carollia brevicauda have the same Xq-autosome translocation (neo-X). Using multicolor FISH we observed different levels of condensation of the original X and Y chromosomes when compared to the translocated autosomal segment, a likely consequence of the nucleolar organizer region blocking spreading of inactivation to the autosomal region of the neo-X. The use of chromosome painting showed the behavior of the sex chromosome trivalent--here called the 'neo-XY body'--in meiosis. We compared the variation between the condensation of the original X and Y and the autosome-sex chromosome axis and described the pairing between the original X-Y segments (pseudoautosomal region) and the XY(2) homologous segments, suggesting genetic activity of the latter during meiosis.
Assuntos
Quirópteros/genética , Coloração Cromossômica , Cromossomo X , Cromossomo Y , Animais , Bandeamento Cromossômico , Heterocromatina/metabolismo , Hibridização in Situ Fluorescente , Cariotipagem , Meiose , Modelos Genéticos , Região Organizadora do Nucléolo/metabolismo , Coloração pela Prata , Especificidade da Espécie , Translocação GenéticaRESUMO
Skinks represent the most diversified squamate reptiles with a great variation in body size and form, and are found worldwide in a variety of habitats. Their remarkable diversification has been accompanied by only a few chromosome rearrangements, resulting in highly-conservative chromosomal complements of these lizards. In this study cross-species chromosome painting using Scincus scincus (2n = 32) as the source genome, was used to detect the chromosomal rearrangements and homologies between the following skinks: Chalcides chalcides (2n = 28), C. ocellatus (2n = 28), Eumeces schneideri (2n = 32), Lepidothyris fernandi (2n = 30), Mabuya quinquetaeniata (2n = 32). The results of this study confirmed a high degree of chromosome conservation between these species. The main rearrangements in the studied skinks involve chromosomes 3, 5, 6 and 7 of S. scincus. These subtelocentric chromosomes are homologous to the p and q arms of metacentric pair 3 and 4 in C. chalcides, C. ocellatus, L. fernandi, and M. quinquetaeniata, while they are entirely conserved in E. schneideri. Other rearrangements involve S. scincus 11 in L. fernandi and M. quinquetaeniata, supporting the monophyly of Lygosominae, and one of the chromosomes S. scincus 12-16, in M. quinquetaeniata. In conclusion, our data support the monophyly of Scincidae and confirm that Scincus-Eumeces plus Chalcides do not form a monophyletic clade, suggesting that the Scincus-Eumeces clade is basal to other members of this family. This study represents the first time the whole genome of any reptile species has been used for cross-species chromosome painting to assess chromosomal evolution in this group of vertebrates.
Assuntos
Coloração Cromossômica , Cromossomos/genética , Evolução Molecular , Genômica , Lagartos/genética , Animais , Linhagem Celular , Sequência Conservada , Fibroblastos/citologia , Fibroblastos/fisiologia , Cariotipagem/métodos , Masculino , FilogeniaRESUMO
The karyotypic relationships of skunks (Mephitidae) with other major clades of carnivores are not yet established. Here, multi-directional chromosome painting was used to reveal the karyological relationships among skunks and between Mephitidae (skunks) and Procyonidae (raccoons). Representative species from three genera of Mephitidae (Mephitis mephitis, 2n = 50; Mephitis macroura, 2n = 50; Conepatus leuconotus, 2n = 46; Spilogale gracilis, 2n = 60) and one species of Procyonidae (Procyon lotor, 2n = 38) were studied. Chromosomal homology was mapped by hybridization of five sets of whole-chromosome paints derived from stone marten (Martes foina, 2n = 38), cat, skunks (M. mephitis; M. macroura) and human. The karyotype of the raccoon is highly conserved and identical to the hypothetical ancestral musteloid karyotype, suggesting that procyonids have a particular importance for establishing the karyological evolution within the caniforms. Ten fission events and five fusion events are necessary to generate the ancestral skunk karyotype from the ancestral carnivore karyotype. Our results show that Mephitidae joins Canidae and Ursidae as the third family of carnivores that are characterized by a high rate of karyotype evolution. Shared derived chromosomal fusion of stone marten chromosomes 6 and 14 phylogenetically links the American hog-nosed skunk and eastern spotted skunk.
Assuntos
Cromossomos de Mamíferos/genética , Rearranjo Gênico/genética , Mephitidae/genética , Filogenia , Animais , Coloração Cromossômica , Hibridização in Situ Fluorescente , Cariotipagem , Especificidade da EspécieRESUMO
The Mus musculus and Rattus norvegicus genomes have been extensively studied, yet despite the emergence of Peromyscus maniculatus as an NIH model for genome sequencing and biomedical research much remains unknown about the genome organization of Peromyscines. Contrary to their phylogenetic relationship, the genomes of Rattus and Peromyscus appear more similar at the gross karyotypic level than either does to Mus. We set out to define the chromosome homologies between Peromyscus, Mus and Rattus. Reciprocal cross-species chromosome painting and G-band homology assignments were used to delineate the conserved chromosome homology map between P. maniculatus and M. musculus. These data show that each species has undergone extensive chromosome rearrangements since they last shared a common ancestor 25 million years ago (mya). This analysis coupled with an inferred homology map with Rattus revealed a high level of chromosome conservation between Rattus and Peromyscus and indicated that the chromosomes of Mus are highly derived.
Assuntos
Mapeamento Cromossômico , Coloração Cromossômica , Camundongos/genética , Peromyscus/genética , Animais , Células Cultivadas , Especificidade da EspécieRESUMO
The spectacled owl (Pulsatrix perspicillata), a species found in the Neotropical region, has 76 chromosomes, with a high number of biarmed chromosomes. In order to define homologies between Gallus gallus and Pulsatrixperspicillata (Strigiformes, Strigidae), we used chromosome painting with chicken DNA probes of chromosomes 1-10 and Z and telomeric sequences. This approach allowed a comparison between Pulsatrixperspicillata and other species of Strigidae already analyzed by chromosome painting (Strix nebulosa and Bubo bubo, both with 2n = 80). The results show that centric fusions and fissions have occurred in different chromosomal pairs and are responsible for the karyotypic variation observed in this group. No interstitial telomeric sequences were found. Although the largest pair of chromosomes in P. perspicillata and Bubo bubo are submetacentric, they are homologous to different chicken chromosomes: GGA1/GGA2 in P. perspicillata and GGA2/GGA4 in B. bubo.
Assuntos
Galinhas/genética , Cromossomos/genética , Evolução Molecular , Estrigiformes/genética , Animais , Coloração Cromossômica , Hibridização in Situ Fluorescente , Cariotipagem , Telômero/genéticaRESUMO
In the absence of an SRY orthologue the platypus sex determining gene is unknown, so genes in the human testis determining pathway are of particular interest as candidates. SOX9 is an attractive choice because SOX9 deletions cause male-to-female sex reversal in humans and mice, and SOX9 duplications cause female-to-male sex reversal. We have localized platypus SOX9, as well as the related SOX10, to platypus chromosomes 15 and 10, respectively, the first assignments to these platypus chromosomes, and the first comparative mapping markers from human chromosomes 17 and 22. The autosomal localization of platypus SOX9 in this study contradicts the hypothesis that SOX9 acts as the sex determining switch in platypus.
Assuntos
Cromossomos de Mamíferos/genética , Proteínas de Grupo de Alta Mobilidade/genética , Mapeamento Físico do Cromossomo , Ornitorrinco/genética , Processos de Determinação Sexual , Fatores de Transcrição/genética , Animais , Coloração Cromossômica , Cromossomos Artificiais Bacterianos , Proteínas de Ligação a DNA/genética , Fatores de Transcrição SOX9 , Fatores de Transcrição SOXERESUMO
Despite marked improvements in the interpretation of systematic relationships within Eutheria, particular nodes, including Paenungulata (Hyracoidea, Sirenia and Proboscidea), remain ambiguous. The combination of a rapid radiation, a deep divergence and an extensive morphological diversification has resulted in a limited phylogenetic signal confounding resolution within this clade both at the morphological and nucleotide levels. Cross-species chromosome painting was used to delineate regions of homology between Loxodonta africana (2n=56), Procavia capensis (2n=54), Trichechus manatus latirostris (2n=48) and an outgroup taxon, the aardvark (Orycteropus afer, 2n=20). Changes specific to each lineage were identified and although the presence of a minimum of 11 synapomorphies confirmed the monophyly of Paenungulata, no change characterizing intrapaenungulate relationships was evident. The reconstruction of an ancestral paenungulate karyotype and the estimation of rates of chromosomal evolution indicate a reduced rate of genomic repatterning following the paenungulate radiation. In comparison to data available for other mammalian taxa, the paenungulate rate of chromosomal evolution is slow to moderate. As a consequence, the absence of a chromosomal character uniting two paenungulates (at the level of resolution characterized in this study) may be due to a reduced rate of chromosomal change relative to the length of time separating successive divergence events.
Assuntos
Coloração Cromossômica , Elefantes/genética , Procaviídeos/genética , Trichechus manatus/genética , Animais , Elefantes/classificação , Evolução Molecular , Procaviídeos/classificação , Masculino , Filogenia , Trichechus manatus/classificaçãoRESUMO
The Vespertilionidae is the largest family in the order Chiroptera and has a worldwide distribution in the temperate and tropical regions. In order to further clarify the karyotype relationships at the lower taxonomic level in Vespertilionidae, genome-wide comparative maps have been constructed between Myotis myotis (MMY, 2n = 44) and six vesper bats from China: Myotis altarium (MAL, 2n = 44), Hypsugo pulveratus (HPU, 2n = 44), Nyctalus velutinus (NVE, 2n = 36), Tylonycteris robustula (TRO, 2n = 32), Tylonycteris sp. (TSP, 2n = 30)and Miniopterus fuliginosus (MFU, 2n = 46) by cross-species chromosome painting with a set of painting probes derived from flow-sorted chromosomes of Myotis myotis. Each Myotis myotis autosomal probe detected a single homologous chromosomal segment in the genomes of these six vesper bats except for MMY chromosome 3/4 paint which hybridized onto two chromosomes in the genome of M. fuliginosus. Our results show that Robertsonian translocation is the main mode of karyotype evolution in Vespertilionidae and that the addition of heterochromatic material also plays an important role in the karyotypic evolution of the genera Tylonycteris and Nyctalus. Two conserved syntenic associations (MMY9 + 23 and 18 + 19) could be the synapomorphic features for the genus Tylonycteris. The integration of our maps with the published maps has enabled us to deduce chromosomal homologies between human and these six vesper bats and provided new insight into the karyotype evolution of the family Vespertilionidae.
Assuntos
Quirópteros/genética , Animais , Células Cultivadas/ultraestrutura , China , Quirópteros/classificação , Bandeamento Cromossômico , Coloração Cromossômica , Cromossomos/genética , Cromossomos/ultraestrutura , Feminino , Fibroblastos/ultraestrutura , Alemanha , Heterocromatina/genética , Heterocromatina/ultraestrutura , Hibridização in Situ Fluorescente , Cariotipagem/veterinária , Masculino , Metáfase , Especificidade da Espécie , Terminologia como Assunto , Translocação GenéticaRESUMO
To assess the contribution of changes in insulin secretion and clearance to the incretin effect (greater insulinemia after oral than after intravenous glucose), 10 healthy subjects were studied after oral glucose (1 g/kg body wt) and again when glucose was infused intravenously at rates to match arterialized plasma glucose concentrations after oral glucose. Although basal and integrated plasma glucose did not differ between oral and intravenous glucose, integrated responses of insulin (3.3 +/- 0.5 vs. 1.8 +/- 0.4 mU ml-1.240 min-1, P less than .001), C-peptide (456.5 +/- 58.5 vs. 327.9 +/- 46.3 ng.ml-1.240 min-1, P = .002), gastric inhibitory polypeptide, (16.8 +/- 3.5 vs. -2.8 +/- 1.0 micrograms.ml-1.240 min-1, P less than .001), and insulin secretion (6.6 +/- 1.1 vs. 4.7 +/- 0.7 U.240 min-1, P = .003) were greater with oral than intravenous glucose. However, insulin clearance, whether calculated as the molar ratio of integrated C-peptide to integrated insulin responses (6.9 +/- 0.7 vs. 14.2 +/- 3.8, P = .005) or from the formula insulin clearance equals insulin secretion divided by integrated insulin responses (1.1 +/- 0.2 vs. 2.5 +/- 0.7 L.min-1.m-2, respectively, P = .002), was less for oral than for intravenous glucose. Therefore, the incretin effect is mediated both by increased secretion and decreased clearance of insulin.
Assuntos
Glucose/administração & dosagem , Insulina/sangue , Administração Oral , Adulto , Glicemia/análise , Peptídeo C/sangue , Feminino , Polipeptídeo Inibidor Gástrico/sangue , Glucose/farmacologia , Humanos , Injeções Intravenosas , Insulina/metabolismo , Secreção de Insulina , Masculino , Valores de Referência , Caracteres SexuaisRESUMO
The quality of the epidemiological data on diabetic neuropathies remains poor for a variety of reasons. They include variability in 1) ascertainment of diabetes, 2) the clinical varieties of diabetic patients studied, 3) characterization of neurological dysfunction, 4) abnormal limits for neurological examinations and tests, 5) minimal criteria for neuropathy, 6) correct attribution of nondiabetic neurological disease, 7) correct attribution of type of neuropathy, 8) estimating neuropathy from use of multiple tests, and 9) estimating severity of polyneuropathy. We have tried to remedy these short-comings in the Rochester Diabetic Neuropathy Study (RDNS). It was not possible to adequately characterize and quantitate diabetic polyneuropathies using only one or two clinical or test abnormalities. To estimate severity of diabetic polyneuropathy, the results of the neurological examination and abnormalities of nerve conduction, quantitative sensory tests, and quantitative autonomic tests were combined into a composite score. One begins by scoring a standard test of neurological deficits (impairments) of the lower limbs (NIS[LL]) and adds to this transformed numbers for percentile abnormality of seven good functional tests. This NIS(LL)+7 tests score appears to provide a much more comprehensive and stable numeric score by which to diagnose and grade severity of diabetic polyneuropathy than does the use of individual clinical or test results. This test score should be useful as a measure of change in diabetic polyneuropathy for purposes of medical practice, epidemiology studies, and controlled clinical trials. The staging approach that we introduced previously continues to provide an important measure of overall severity of diabetic polyneuropathy, taking into account both symptoms and impairments.
Assuntos
Neuropatias Diabéticas/epidemiologia , Estudos Transversais , Diabetes Mellitus/diagnóstico , Neuropatias Diabéticas/diagnóstico , Humanos , Estudos Longitudinais , Projetos de PesquisaRESUMO
The perioperative and follow-up results of cardiac operations employing extracorporeal circulation and cold cardioplegic arrest were examined in 191 consecutive patients greater than or equal to 80 years of age having surgery over a 5 year period (1982 to 1986). Most patients had severe preoperative symptoms with functional class III (39.8%) or IV (57.1%) limitation. The overall 30 day postoperative cardiac mortality rate was 15.7%. The total in-hospital mortality rate was 18.8%; the mean postoperative hospital stay was 16.4 +/- 13.3 days. The perioperative mortality rate for elective operations was as follows: coronary artery bypass (5.6%), aortic valve replacement (9.6%), aortic valve replacement with coronary bypass (17.9%) and mitral valve surgery with or without coronary bypass (21.4%). Urgent operations were performed in 39 patients (20.4%) with a total perioperative mortality rate of 35.9%; urgent coronary artery bypass was performed in 26 patients (67%) with an in-hospital mortality rate of 23.1%. Clinical evidence of left ventricular failure, functional class IV symptoms, left ventricular ejection fraction less than 50%, mitral valve repair or replacement for severe mitral regurgitation and urgent operation were associated with an increased perioperative mortality rate. Follow-up study in all 155 patients surviving postoperative hospitalization at 22.6 +/- 14.8 months showed significant improvement in symptom status in all surgical subgroups. There were 18 follow-up deaths (11.6%); 10 were noncardiac. The actuarial survival rate of the entire study group was significantly better than that in age- and gender-matched control subjects (p = 0.037).(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Idoso de 80 Anos ou mais , Procedimentos Cirúrgicos Cardíacos/mortalidade , Complicações Pós-Operatórias/mortalidade , Análise Atuarial , Idoso , Análise Custo-Benefício , Circulação Extracorpórea , Feminino , Seguimentos , Parada Cardíaca Induzida , Humanos , Tempo de Internação , Masculino , Fatores de RiscoRESUMO
Chromosome sorting by flow cytometry is the main source of chromosome-specific DNA for the production of painting probes. These probes have been used for cross-species in situ hybridization in the construction of comparative maps, in the study of karyotype evolution and phylogenetics, in delineating territories in interphase nuclei, and in the analysis of chromosome breakpoints. We review here the contributions that this technology has made to the analysis of primate genomes.