RESUMO
INTRODUCTION: Muscle mass and function are among the most relevant factors that contribute to an optimal quality of life, and are strong predictors of mortality in the elderly. Loss of lean tissues and deterioration of muscle function have been described as one of the many complications of type 2 diabetes mellitus (DM2), but most studies do not isolate age as an intervening factor. AIM: To study whether adult DM2 patients up to 60years of age have decreased muscle mass and function compared with healthy non-diabetic (ND) subjects of similar age. METHODOLOGY: Appendicular fat-free mass (ApFFM) by dual X-ray absorptiometry (DEXA), handgrip strength (HS), quadriceps strength (QS), 12 min walking capacity (12MW) and the Timed Up and Go test (TUG) were measured in 100 DM2 patients and 39 ND controls. Muscle quality, or the ratio between lean mass and muscle strength of upper and lower limbs, and the functional limitations associated with pain and stiffness assessed according to the Western Ontario and McMaster Universities Arthrosis Index (WOMAC) were also recorded. Specific tests were performed to rule out microvascular diabetic complications (retinal and peripheral nerves), metabolic control, kidney function and vitamin D status and examine their association with ApFFM and function. RESULTS: ApFFM was significantly higher among DM2 female patients and lower among diabetic men. However opposite results were obtained when individual values were corrected for body mass index (BMI), specifically among women, who were more likely to be obese. As for muscle strength and global functionality tests, significantly better performances in TUG, 12MW, QS and HS were observed among ND subjects of both sexes. These differences prevailed even after excluding diabetic patients with microvascular complications as well as those with more than 10years of diabetes. Muscle quality was also significantly better among ND women. Higher scores of pain and stiffness in the WOMAC scale correlated with 12MW and TUG in both groups but did not correlate with ApFFM. CONCLUSIONS: We found a clear deterioration of lean mass and muscle functions among adult DM2 patients of up to 60years old, independent of length of disease, metabolic control, vitamin D status and presence of microvascular complications and pain.
Assuntos
Complicações do Diabetes/etiologia , Diabetes Mellitus Tipo 2/complicações , Força da Mão/fisiologia , Força Muscular/fisiologia , Qualidade de Vida , Sarcopenia/etiologia , Absorciometria de Fóton , Adulto , Estudos de Casos e Controles , Complicações do Diabetes/diagnóstico , Diabetes Mellitus Tipo 2/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ontário , Sarcopenia/diagnóstico , CaminhadaRESUMO
Paraquat is still a widely used herbicide in several countries. Its toxic action on plants occurs through a one-electron reduction interfering with the photosynthesis process. By a similar reaction, the herbicide may induce peroxidation processes in non-target animal species. Furthermore, paraquat may interfere with the cellular transport of polyamines. The aim of this work was to investigate some aspects related to paraquat-induction of oxidative stress (lipoperoxidation, enzymatic activities of catalase and superoxide dismutase) and also the levels of polyamines (putrescine, spermidine and spermine) in two species of freshwater invertebrates, the oligochaete Lumbriculus variegatus and the gastropod Biomphalaria glabrata. The results showed that both organisms elicited differential responses. In addition, the data suggested that polyamines may play an important role against lipoperoxidation processes.
Assuntos
Biomphalaria/efeitos dos fármacos , Herbicidas/toxicidade , Oligoquetos/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Paraquat/toxicidade , Poliaminas/metabolismo , Animais , Biomphalaria/enzimologia , Biomphalaria/metabolismo , Catalase/metabolismo , Água Doce , Peroxidação de Lipídeos/efeitos dos fármacos , Oligoquetos/enzimologia , Oligoquetos/metabolismo , Putrescina/metabolismo , Espermidina/metabolismo , Espermina/metabolismo , Superóxido Dismutase/metabolismo , Fatores de TempoRESUMO
The complex and variable composition of natural sediments makes it very difficult to predict the bioavailability and bioaccumulation of sediment-bound contaminants. Several approaches have been proposed to overcome this problem, including an experimental model using artificial particles with or without humic acids as a source of organic matter. For this work, we have applied this experimental model, and also a sample of a natural sediment, to investigate the uptake and bioaccumulation of 2,4-dichlorophenol (2,4-DCP) by Sphaerium corneum. Additionally, the particle-water partition coefficients (K(d)) were calculated. The results showed that the bioaccumulation of 2,4-DCP by clams did not depend solely on the levels of chemical dissolved, but also on the amount sorbed onto the particles and the characteristics and the strength of that binding. This study confirms the value of using artificial particles as a suitable experimental model for assessing the fate of sediment-bound contaminants.
Assuntos
Bivalves/metabolismo , Clorofenóis/farmacocinética , Sedimentos Geológicos , Substâncias Húmicas , Poluentes Químicos da Água/farmacocinética , Silicatos de Alumínio , Animais , Disponibilidade Biológica , Argila , Água Doce , Concentração de Íons de Hidrogênio , Modelos Biológicos , Resinas SintéticasRESUMO
Hydrophobic chemicals are known to associate with sediment particles including those from both suspended particulate matter and bottom deposits. The complex and variable composition of natural particles makes it very difficult therefore, to predict the bioavailability of sediment-bound contaminants. To overcome these problems we have previously devised a test system using artificial particles, with or without humic acids, for use as an experimental model of natural sediments. In the present work we have applied this experimental technique to investigate the bioavailability and bioaccumulation of pyrene by the freshwater fingernail clam Sphaerium corneum. The uptake and accumulation of pyrene in clams exposed to the chemical in the presence of a sample of natural sediment was also investigated. According to the results obtained, particle surface properties and organic matter content are the key factors for assessing the bioavailability and bioaccumulation of pyrene by clams.
Assuntos
Bivalves/química , Pirenos/análise , Testes de Toxicidade/métodos , Poluentes Químicos da Água/análise , Absorção , Análise de Variância , Animais , Disponibilidade Biológica , Sedimentos Geológicos , Substâncias Húmicas , Tamanho da PartículaRESUMO
Acute static bioassays were performed using three freshwater invertebrate species (the oligochaete Lumbriculus variegatus, the fingernail clam Sphaerium corneum and the larvae Chironomus riparius) exposed separately to a variety of 14C radiolabelled contaminants. The aim of this work was to investigate if the chemicals remained as parent compounds after the treatments. Chemicals used were 2,4-dichlorophenol; 2,4,5-trichlorophenol; pentachlorophenol; pyrene; Fenpropidin, and Trifluralin. Homogenates of the whole body tissue of each organism were prepared and total radioactivity was measured. Contaminants were then extracted into organic solvents and analysed by high-pressure liquid chromatography techniques. Chromatograms showed that most of the substances extracted were present as parent compounds in S. corneum and in L. variegatus. In contrast, for C. riparius a low proportion of the chemicals was recovered as parent compounds. These results suggest that different metabolic processes could take place in the different species.
Assuntos
Água Doce/química , Invertebrados/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Bioensaio , Biotransformação , Bivalves/metabolismo , Radioisótopos de Carbono , Clorofenóis/metabolismo , Cromatografia Líquida de Alta Pressão , Larva/metabolismo , Oligoquetos/metabolismo , Pentaclorofenol/metabolismo , Piperidinas/metabolismo , Pirenos/metabolismo , Trifluralina/metabolismoRESUMO
Studies of genetic structures of Andean human populations have not been numerous, even though these studies could be used to answer questions concerning migration routes of the indigenous peoples who populated America. Such studies could provide basic genetic information and clarify uncertainties surrounding genetic relatedness of South American indigenous peoples. This present work describes, quantifies, and analyzes the digital and palmar dermatoglyphics of 120 people in the community of San Pedro de Casta, Perú. The results were then compared using distance analysis to all other Peruvian population values studied to date and other South American populations. The dermatoglyphic indicators studied were the distribution of digital pattern frequencies, the total ridge counts (TRC), the pattern intensity index (PII), the atd angle, and the a-b ridge counts. The results did not show statistically significant differences for digital patterns between hands, neither within a sex nor between sexes. The means and standard deviations of PII and TRC were 12.32 +/- 3.97 and 112.18 +/- 45.09, respectively. The means and standard deviations for the other two indicators were the following: atd angle, 94.85 degrees +/- 12.33; and a-b ridge counts, 81.57 +/- 9.06. The distance analyses results suggest the existence of two different genetic lines among high altitude populations, as well as the need for further research.
Assuntos
Altitude , Povo Asiático/genética , Dermatoglifia , Indígenas Sul-Americanos/genética , Adolescente , Criança , Feminino , Humanos , Masculino , PeruRESUMO
The uptake of anthropogenic chemicals by benthic bivalves may occur through the water phase and also by the ingestion of particles from both the suspended matter and bottom sediments. Many chemicals sorb to sediments and, subsequently, are released in the digestive tract of animals. The assessment of sediment-bound chemicals has been difficult because of the complexity of the association between these chemicals and natural particles. To simplify this complexity, we previously devised a test system using artificial particles with known chemical structures. In the present work, we improved this experimental design by adding humic materials as a source of organic matter. Bioassays were conducted by exposing the fingernail clam Sphaerium corneum to sublethal levels of pentachlorophenol (PCP) in the presence or absence of the artificial particles, treated with or without a commercial preparation of humic acids. The results showed that the bioavailability and bioaccumulation could be explained on the basis of the interactions of PCP with the active groups and/or the backbone of the resins, both in systems with or without humic acids. This model may constitute a useful approach to modeling and predicting the uptake and accumulation of chemicals bound to natural sediments.
Assuntos
Bivalves , Exposição Ambiental , Poluentes Ambientais/farmacocinética , Modelos Biológicos , Pentaclorofenol/farmacocinética , Poluentes Químicos da Água/farmacocinética , Animais , Disponibilidade Biológica , Poluentes Ambientais/análise , Previsões , Substâncias Húmicas/análise , Substâncias Húmicas/farmacocinética , Tamanho da Partícula , Pentaclorofenol/análise , Medição de Risco , Distribuição Tecidual , Poluentes Químicos da Água/análiseRESUMO
UNLABELLED: The risk for premature ovarian failure (POF) in females with galactosemia can be predicted by analyzing 3 areas of risk pathology: the patient's molecular genotype for galactose-1-phosphate uridyltransferase (GALT), alternate pathways for galactose metabolism, and the patient's environment at diagnosis and during treatment. STUDY DESIGN: Retrospective cross-sectional information was collected on 53 females with classic galactosemia, and their ovarian function was analyzed by determination of serum follicle-stimulating hormone and luteinizing hormone levels and by clinical observation. The associations were analyzed between POF and the mutations in GALT, the highest erythrocyte galactose-1-phosphate (Gal-1-P) level at diagnosis, the age at which dietary treatment was initiated, mean erythrocyte Gal-1-P level during treatment, and whole-body carbon 13-labeled galactose oxidation to (13)CO(2). RESULTS: The most prevalent mutation, Q188R, had a significant effect of genotype category (Q188R/Q188R, Q188R/Other, Other/Other) on POF (P =.04, Fisher exact test and an odds ratio of 8.3). Mean erythrocyte Gal-1-P level during treatment was a significant risk factor for POF (P =.04). Also, all patients studied with less than 5% total body oxidation of galactose to (13)CO(2) had POF, whereas those with more than 5% did not have POF (P =.008, Fisher exact test). CONCLUSION: The development of POF in females with galactosemia is more likely if the patient's genotype is Q188R/Q188R, if the mean erythrocyte Gal-1-P is >3.5 mg/dL during therapy, and if the recovery of (13)CO(2) from whole-body (13)C-galactose oxidation is reduced below 5% of administered (13)C-galactose.
Assuntos
Galactosemias/complicações , Insuficiência Ovariana Primária/etiologia , Adolescente , Adulto , Criança , Pré-Escolar , Estudos Transversais , Feminino , Hormônio Foliculoestimulante/sangue , Galactosemias/dietoterapia , Galactosemias/genética , Genótipo , Humanos , Lactente , Mutação Puntual/genética , Insuficiência Ovariana Primária/diagnóstico , Insuficiência Ovariana Primária/epidemiologia , Estudos Retrospectivos , Fatores de Risco , UTP-Hexose-1-Fosfato Uridililtransferase/sangue , UTP-Hexose-1-Fosfato Uridililtransferase/genéticaRESUMO
The Snail family of genes comprise a group of transcription factors with characteristic zinc finger motifs. One of the members of this family is the Slug gene. Slug has been implicated in the development of neural crest in chick and Xenopus by antisense loss of function experiments. Here, we have generated functional derivatives of Xslug by constructing cDNAs that encode the Xslug protein fused with the transactivation domain of the virus-derived VP16 activator or with the repressor domain of the Drosophila Engrailed protein. Our results suggest that Xslug normally functions as a transcriptional repressor and that Xslug-VP16 behaves as a dominant negative of Xslug. In the present work, we confirm and extend previous results that suggest that Xslug has an important function in neural crest development, by controlling its own transcription. In addition we have uncovered a new function for Xslug. We show that Xslug is expressed in the dorsal mesendoderm at the beginning of gastrulation, where is it able to upregulate the expression of dorsal genes. On the other hand when Xslug is expressed outside of the organizer it represses the expression of ventral genes. Our results indicate that this effect on mesodermal patterning depends on BMP activity, showing that Xslug can directly control the transcription of BMP-4.
Assuntos
Proteínas Morfogenéticas Ósseas/genética , Proteínas de Drosophila , Regulação da Expressão Gênica no Desenvolvimento , Glicoproteínas , Peptídeos e Proteínas de Sinalização Intercelular , Mesoderma/fisiologia , Proteínas Repressoras/fisiologia , Fatores de Transcrição/fisiologia , Proteínas de Xenopus , Proteínas de Peixe-Zebra , Animais , Biomarcadores , Proteína Morfogenética Óssea 4 , Núcleo Celular/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Ectoderma/metabolismo , Ectoderma/fisiologia , Proteínas de Homeodomínio/genética , Mesoderma/metabolismo , Crista Neural/metabolismo , Organizadores Embrionários/metabolismo , Fator de Transcrição PAX3 , Fatores de Transcrição Box Pareados , Proteínas/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/fisiologia , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Fatores de Transcrição da Família Snail , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas Wnt , Xenopus laevis/embriologia , Dedos de ZincoRESUMO
We have analyzed the role of mesoderm in the induction of the neural crest in Xenopus using expression of neural plate (Xsox-2) and neural crest (Xslug and ADAM). Conjugation experiments using different kinds of mesoderm together with embryonic dissection experiments suggest that the dorsolateral mesoderm is capable of specifically inducing neural crest cells. Neural crest markers can be induced in competent ectoderm at varying distances from the inducing mesoderm, with dorsal tissue inducing neural crest at a distance while dorsolateral tissue only induces neural crest directly in adjacent ectoderm. The results suggest that dorsal mesoderm has a high level of inducer and dorsolateral mesoderm has a lower level, consistent with a inductive gradient. We explored the possible role of BMP and noggin in the generation of such a hypothetical gradient and found that: (1) progressively higher levels of BMP activity are sufficient for the specification of neural plate, neural crest, and nonneural cells, respectively; (2) progressively higher levels of noggin are able to induce neural crest at greater distances from the source of inducer; and (3) modification of the levels of BMP activity causes induction of the neural crest in absence of neural plate, suggesting independent induction of these two tissues. We propose a model in which a gradient of BMP activity is established in the ectoderm by interaction between BMP in the ectoderm and BMP inhibitors in the mesoderm. Neural crest is induced when a threshold level of BMP is attained in the ectoderm. The dorsolateral mesoderm produces either BMP inhibitors or a specific neural crest inducer, with low BMP activity inducing neural plate while high BMP activity induces epidermis.
Assuntos
Proteínas Morfogenéticas Ósseas/fisiologia , Mesoderma/fisiologia , Crista Neural/fisiologia , Animais , Indução Embrionária , Feminino , Crista Neural/citologia , Xenopus/embriologiaRESUMO
A study of the molecules noggin and fibroblast growth factor (FGF) and its receptor in the induction of the prospective neural crest in Xenopus laevis embryos has been carried out, using the expression of the gene Xslu as a marker for the neural crest. We show that when a truncated FGF receptor (XFD) was expressed ectopically in order to block FGF signaling Xslu expression was inhibited. The effect of XFD on Xslu was specific and could be reversed by the coinjection of the wild-type FGF receptor (FGFR). Inhibition of Xslu expression by XFD is not a consequence of neural plate inhibition, as was shown by analyzing Xsox-2 expression. When ectoderm expressing XFD was transplanted into the prospective neural fold region of embryos Xslu induction was inhibited. The neural crest can also be induced by an interaction between neural plate and epidermis. As this induction is suppressed by the presence of XFD in the neural plate and not in the epidermis, it suggests that the neural crest is induced by FGF from the epidermis. However, treatment of neural plate with FGF was not able to induce Xslug expression, showing that in addition to FGF other non-FGF factors are also required. Previously we have suggested that the ectopic ventral expression of Xslu produced by overexpression of noggin mRNA resulted from an interaction of noggin with a ventral signal. Overexpression of XFD inhibits this effect, suggesting that FGF could be one component involved in this ventral signaling. Overexpression of FGFR produced a remarkable increase in the expression of Xslu in the posterior neural folds and around the blastopore. Injections in different blastomeres of the embryo suggest that the target cells of this effect are the ventral cells. Finally, we proposed a model in which the induction of the neural crests at the border of the neural plate requires functional FGF signaling, which possibly interacts with a neural inducer such as noggin.