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1.
PLoS One ; 13(2): e0192172, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29466362

RESUMO

How extinct, non-avian theropod dinosaurs moved is a subject of considerable interest and controversy. A better understanding of non-avian theropod locomotion can be achieved by better understanding terrestrial locomotor biomechanics in their modern descendants, birds. Despite much research on the subject, avian terrestrial locomotion remains little explored in regards to how kinematic and kinetic factors vary together with speed and body size. Here, terrestrial locomotion was investigated in twelve species of ground-dwelling bird, spanning a 1,780-fold range in body mass, across almost their entire speed range. Particular attention was devoted to the ground reaction force (GRF), the force that the feet exert upon the ground. Comparable data for the only other extant obligate, striding biped, humans, were also collected and studied. In birds, all kinematic and kinetic parameters examined changed continuously with increasing speed, while in humans all but one of those same parameters changed abruptly at the walk-run transition. This result supports previous studies that show birds to have a highly continuous locomotor repertoire compared to humans, where discrete 'walking' and 'running' gaits are not easily distinguished based on kinematic patterns alone. The influences of speed and body size on kinematic and kinetic factors in birds are developed into a set of predictive relationships that may be applied to extinct, non-avian theropods. The resulting predictive model is able to explain 79-93% of the observed variation in kinematics and 69-83% of the observed variation in GRFs, and also performs well in extrapolation tests. However, this study also found that the location of the whole-body centre of mass may exert an important influence on the nature of the GRF, and hence some caution is warranted, in lieu of further investigation.


Assuntos
Dinossauros/fisiologia , Extinção Biológica , Locomoção , Adulto , Animais , Fenômenos Biomecânicos , Feminino , Humanos , Masculino
2.
Plant Dis ; 89(4): 404-411, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30795457

RESUMO

A large environmental influence on phenotypic estimates of disease resistance and the complex polygenic nature of Fusarium head blight (FHB) resistance in wheat (Triticum aestivum) are impediments to developing resistant cultivars. The objective of this research was to investigate the utility of a detached leaf assay, inoculated using inoculum from isolates of Microdochium nivale var. majus, to identify components of FHB resistance among 30 entries of U.S. soft red winter wheat in the 2002 Uniform Southern FHB Nursery (USFHBN). Whole plant FHB resistance of the USFHBN entries was evaluated in replicated, mist-irrigated field trials at 10 locations in eight states during the 2001-2002 season. Incubation period (days from inoculation to the first appearance of a dull gray-green water-soaked lesion) was the only detached leaf variable significantly correlated across all FHB resistance parameters accounting for 45% of the variation in FHB incidence, 27% of FHB severity, 30% of Fusarium damaged kernels, and 26% of the variation in grain deoxynivalenol (DON) concentration. The results for incubation period contrasted with previous studies of moderately resistant European cultivars, in that longer incubation period was correlated with greater FHB susceptibility, but agreed with previous findings for the Chinese cultivar Sumai 3 and CIMMYT germ plasm containing diverse sources of FHB resistance. The results support the view that the detached leaf assay method has potential for use to distinguish between specific sources of FHB resistance when combined with data on FHB reaction and pedigree information. For example, entry 28, a di-haploid line from the cross between the moderately resistant U.S. cultivar Roane and the resistant Chinese line W14, exhibited detached leaf parameters that suggested a combination of both sources of FHB resistance. The USFHBN represents the combination of adapted and exotic germ plasm, but four moderately resistant U.S. commercial cultivars (Roane, McCormick, NC-Neuse, and Pat) had long incubation and latent periods and short lesion lengths in the detached leaf assay as observed in moderately FHB resistant European cultivars. The dichotomy in the relationship between incubation period and FHB resistance indicates that this may need to be considered to effectively combine exotic and existing/adapted sources of FHB resistance.

3.
Cogn Neuropsychiatry ; 1(3): 213-20, 1996 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-16571487

RESUMO

There are two currently influential views regarding the link between cognitive distortions and depression. The first states that depressed individuals perceive the world and themselves with a strong negative bias or distortion, and that mentally healthy individuals perceive the word with relative accuracy. The second ''depressive realism'' camp argues that healthy individuals are positively biased and the depressed are relatively unbiased and hence, more realistic. In the present investigation, subjects suffering from major depression, subjects recovered from major depression, and a group of healthy controls were examined with regard to their confidence in answering each of 99 general knowledge questions. Confidence ratings were analysed separately according to correct or incorrect responses. There were no significant differences in performance (i.e. accuracy of answer between the three groups). When answering correctly, depressed subjects were significantly less confident than healthy control subjects. On answering incorrectly, none of the three groups were significantly different in their confidence ratings. These findings support the cognitive distortion view of depression and provide no evidence of ''depressive realism''.

5.
Diabetes ; 42(12): 1773-85, 1993 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8243823

RESUMO

Mechanisms causing cellular insulin resistance in gestational diabetes mellitus are not known. We, therefore, studied isolated omental adipocytes obtained during elective cesarean sections in nondiabetic (control) and GDM gravidas. Cellular insulin resistance was attributed to impaired stimulation of glucose transport; compared with control subjects, basal and maximally insulin-stimulated transport rates (per surface area) were reduced 38 and 60% in GDM patients, respectively. To determine underlying mechanisms, we assessed the number, subcellular distribution, and translocation of GLUT4, the predominant insulin-responsive glucose transporter isoform. The cellular content of GLUT4 was decreased by 44% in GDM patients as assessed by immunoblot analysis of total postnuclear membranes. However, GDM patients segregated into two subgroups; half expected profound (76%) cellular depletion of GLUT4 and half had GLUT4 levels in the normal range. Cellular GLUT4 was negatively correlated with adipocyte size in the control subjects and GDM patients with normal GLUT4 (r = 0.60), but fell way below this continuum in GDM patients with low GLUT4, indicating that heterogeneity was not caused by differences in obesity. All GDM. distribution. In basal cells, increased amounts of GLUT4 were detected in membranes fractionating with (such that the plasma membrane GLUT4 level in GDM (such that the plasma membrane GLUT4 level in GDM patients was equal to that observed in insulin-stimulated cells from control subjects). Furthermore, insulin stimulation induced translocation of GLUT4 from low-density microsomes to plasma membranes in control subjects but did not alter subcellular distribution in GDM patients. In other experiments, cellular content of GLUT1 was normal in GDM patients, and GLUT1 did not undergo insulin-mediated recruitment to plasma membranes in either control subjects or GDM patients. A faint signal was detected for GLUT3 only in low-density microsomes and only with one of two different antibodies. In GDM, we conclude that insulin resistance in adipocytes involves impaired stimulation of glucose transport and arises from a heterogeneity of defects intrinsic to the glucose transport effector system. GLUT4 content in adipocytes is profoundly depleted in approximately 50% of GDM patients, whereas all patients are found to exhibit a novel abnormality in GLUT4 subcellular distribution. This latter defect is characterized by accumulation of GLUT4 in membranes cofractionating with plasma membranes and high-density microsomes in basal cells and absence of translocation in response to insulin. The data suggest that abnormalities in cellular traffic or targeting relegate GLUT4 to a membrane compartment from which insulin cannot recruit transporters to the cell surface and have important implications regarding skeletal muscle insulin resistance in GDM and NIDDM.


Assuntos
Adipócitos/metabolismo , Diabetes Gestacional/metabolismo , Glucose/metabolismo , Resistência à Insulina/fisiologia , Proteínas de Transporte de Monossacarídeos/metabolismo , Proteínas Musculares , Adulto , Análise de Variância , Peso ao Nascer , Membrana Celular/metabolismo , Células Cultivadas , Cesárea , Diabetes Gestacional/fisiopatologia , Feminino , Expressão Gênica , Transportador de Glucose Tipo 4 , Humanos , Recém-Nascido , Proteínas de Transporte de Monossacarídeos/biossíntese , Omento , Gravidez , Valores de Referência
6.
Diabetes ; 41(4): 465-75, 1992 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-1535055

RESUMO

In obesity, impaired glucose tolerance (IGT), non-insulin-dependent diabetes mellitus (NIDDM), and gestational diabetes mellitus (GDM), defects in glucose transport system activity, contribute to insulin resistance in target tissues. In adipocytes from obese and NIDDM patients, we found that pretranslational suppression of the insulin-responsive GLUT4 glucose transporter isoform is a major cause of cellular insulin resistance; however, whether this process is operative in skeletal muscle is not clear. To address this issue, we performed percutaneous biopsies of the vastus lateralis in lean and obese control subjects and in obese patients with IGT and NIDDM and open biopsies of the rectus abdominis at cesarian section in lean and obese gravidas and gravidas with GDM. GLUT4 was measured in total postnuclear membrane fractions from both muscles by immunoblot analyses. The maximally insulin-stimulated rate of in vivo glucose disposal, assessed with euglycemic glucose clamps, decreased 26% in obesity and 74% in NIDDM, reflecting diminished glucose uptake by muscle. However, in vastus lateralis, relative amounts of GLUT4 per milligram membrane protein were similar (NS) among lean (1.0 +/- 0.2) and obese (1.5 +/- 0.3) subjects and patients with IGT (1.4 +/- 0.2) and NIDDM (1.2 +/- 0.2). GLUT4 content was also unchanged when levels were normalized per wet weight, per total protein, and per DNA as an index of cell number. Levels of GLUT4 mRNA were similarly not affected by obesity, IGT, or NIDDM whether normalized per RNA or for the amount of an unrelated constitutive mRNA species. Because muscle fibers (types I and II) exhibit different capacities for insulin-mediated glucose uptake, we tested whether a change in fiber composition could cause insulin resistance without altering overall levels of GLUT4. However, we found that quantities of fiber-specific isoenzymes (phopholamban and types I and II Ca(2+)-ATPase) were similar in all subject groups. In rectus abdominis, GLUT4 content was similar in the lean, obese, and GDM gravidas whether normalized per milligram membrane protein (relative levels were 1.0 +/- 0.2, 1.3 +/- 0.1, and 1.0 +/- 0.2, respectively) or per wet weight, total protein, and DNA. We conclude that in human disease states characterized by insulin resistance, i.e., obesity, IGT, NIDDM, and GDM, GLUT4 gene expression is normal in vastus lateralis or rectus abdominis. To the extent that these muscles are representative of total muscle mass, insulin resistance in skeletal muscle may involve impaired GLUT4 function or translocation and not transporter depletion as observed in adipose tissue.


Assuntos
Diabetes Mellitus Tipo 2/genética , Diabetes Gestacional/genética , Expressão Gênica/genética , Resistência à Insulina/genética , Proteínas de Transporte de Monossacarídeos/genética , Proteínas Musculares , Músculos/metabolismo , Obesidade/genética , Adulto , ATPases Transportadoras de Cálcio/análise , DNA/análise , DNA/genética , Feminino , Expressão Gênica/efeitos dos fármacos , Teste de Tolerância a Glucose , Transportador de Glucose Tipo 4 , Humanos , Immunoblotting , Masculino , Pessoa de Meia-Idade , Proteínas de Transporte de Monossacarídeos/análise , Proteínas de Transporte de Monossacarídeos/metabolismo , Músculos/química , Músculos/patologia , Gravidez , RNA Mensageiro/análise , RNA Mensageiro/genética
8.
Obstet Gynecol ; 52(4): 470-5, 1978 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-714330

RESUMO

This study covers 20 years' experience in the treatment of carcinoma of the cervix. Improved results and a decreased rate of major complications are seen as a result of a cooperative approach in treatment planning and careful dosimetry. Comparisons are made with large treatment centers as well as with national survival rates. Preliminary results with improved radiotherapeutic techniques continue to show improvement in survival rates.


Assuntos
Rádio (Elemento)/uso terapêutico , Neoplasias do Colo do Útero/radioterapia , Medicina de Família e Comunidade , Feminino , Cirurgia Geral , Ginecologia , Humanos , Equipe de Assistência ao Paciente , Radiologia , Neoplasias do Colo do Útero/mortalidade , Neoplasias do Colo do Útero/patologia
10.
Ann Rheum Dis ; 34(4): 364-8, 1975 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-1103755

RESUMO

Three cases of Reiter's disease occurring in boys under the age of 16 are reported. One of these presented with a Salmonella enteritidis diarrhoea. This conforms to the 'dysenteric' form of Reiter's disease usually seen in Europe and rarely reported in England. Another presented with a monarticular arthritis of the knee, and the third has developed a chronic relapsing erosive arthritis as a result of sexually acquired Reiter's disease--an occurrence not previously reported in this age group. We draw attention to the frequency of diarrhoea in these children and the sex incidence of 1 female to 4--5 males, which agrees more with Reiter's disease of dysenteric origin than that acquired venereally.


Assuntos
Artrite Reativa , Adolescente , Artrite/complicações , Artrite Reativa/complicações , Artrite Reativa/tratamento farmacológico , Artrite Reativa/microbiologia , Diarreia/complicações , Diarreia/tratamento farmacológico , Diarreia/microbiologia , Humanos , Indometacina/uso terapêutico , Masculino , Fenilbutazona/uso terapêutico , Salmonella enteritidis/isolamento & purificação , Tetraciclina/uso terapêutico
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