Insulin resistance is associated with higher intramyocellular triglycerides in type I but not type II myocytes concomitant with higher ceramide content.

OBJECTIVE: We tested the primary hypotheses that sphingolipid and diacylglycerol (DAG) content is higher within insulin-resistant muscle and that the association between intramyocellular triglycerides (IMTG) and insulin resistance is muscle fiber type specific. RESEARCH DESIGN AND METHODS: A nested case-control analysis was conducted in 22 obese (BMI >30 kg/m(2)) women who were classified as insulin-resistant (IR; n = 12) or insulin-sensitive (IS; n = 10), determined by hyperinsulinemic-euglycemic clamp (>30% greater in IS compared with IR, P < 0.01). Sphingolipid and DAG content was determined by high-performance liquid chromatography-tandem mass spectrometry. Fiber type-specific IMTG content was histologically determined. Gene expression was determined by quantitative PCR. RESULTS: Total (555 +/- 53 vs. 293 +/- 54 pmol/mg protein, P = 0.004), saturated (361 +/- 29 vs. 179 +/- 34 pmol/mg protein, P = 0.001), and unsaturated (198 +/- 29 vs. 114 +/- 21 pmol/mg protein, P = 0.034) ceramides were higher in IR compared with IS. DAG concentrations, however, were similar. IMTG content within type I myocytes, but not type II myocytes, was higher in IR compared with IS subjects (P = 0.005). Insulin sensitivity was negatively correlated with IMTG within type I myocytes (R = -0.51, P = 0.026), but not with IMTG within type II myocytes. The proportion of type I myocytes was lower (41 vs. 59%, P < 0.01) in IR subjects. Several genes involved in lipid droplet and fatty acid metabolism were differentially expressed in IR compared with IS subjects. CONCLUSIONS: Human skeletal muscle insulin resistance is related to greater IMTG content in type I but not type II myocytes, to greater ceramide content, and to alterations in gene expression associated with lipid metabolism

Residual absorption at zero temperature in d-wave superconductors

In a d-wave superconductor with elastic impurity scattering, not all the available optical spectral weight goes into the condensate at zero temperature, and this leads to residual absorption. We find that for a range of impurity parameters in the intermediate coupling regime between Born (weak) and unitary (strong) limit, significant oscillator strength remains which exhibits a cusp like behavior of the real part of the optical conductivity with upward curvature as a function of frequency, as well as a quasilinear temperature dependence of the superfluid density. The calculations offer an explanation of recent data on ortho-II YBa$_2$Cu$_3$O$_{6.5}$ which has been considered anomalous.Comment: Accepted for publication by Phys. Rev. B 7 Pages and 4 Figure

Singularly Perturbed Monotone Systems and an Application to Double Phosphorylation Cycles

The theory of monotone dynamical systems has been found very useful in the modeling of some gene, protein, and signaling networks. In monotone systems, every net feedback loop is positive. On the other hand, negative feedback loops are important features of many systems, since they are required for adaptation and precision. This paper shows that, provided that these negative loops act at a comparatively fast time scale, the main dynamical property of (strongly) monotone systems, convergence to steady states, is still valid. An application is worked out to a double-phosphorylation ``futile cycle'' motif which plays a central role in eukaryotic cell signaling.Comment: 21 pages, 3 figures, corrected typos, references remove

Sum rules and energy scales in the high-temperature superconductor YBa2Cu3O6+x

The Ferrell-Glover-Tinkham (FGT) sum rule has been applied to the temperature dependence of the in-plane optical conductivity of optimally-doped YBa_2Cu_3O_{6.95} and underdoped YBa_2Cu_3O_{6.60}. Within the accuracy of the experiment, the sum rule is obeyed in both materials. However, the energy scale \omega_c required to recover the full strength of the superfluid \rho_s in the two materials is dramatically different; \omega_c \simeq 800 cm^{-1} in the optimally doped system (close to twice the maximum of the superconducting gap, 2\Delta_0), but \omega_c \gtrsim 5000 cm^{-1} in the underdoped system. In both materials, the normal-state scattering rate close to the critical temperature is small, \Gamma < 2\Delta_0, so that the materials are not in the dirty limit and the relevant energy scale for \rho_s in a BCS material should be twice the energy gap. The FGT sum rule in the optimally-doped material suggests that the majority of the spectral weight of the condensate comes from energies below 2\Delta_0, which is consistent with a BCS material in which the condensate originates from a Fermi liquid normal state. In the underdoped material the larger energy scale may be a result of the non-Fermi liquid nature of the normal state. The dramatically different energy scales suggest that the nature of the normal state creates specific conditions for observing the different aspects of what is presumably a central mechanism for superconductivity in these materials.Comment: RevTeX 4 file, 9 pages with 7 embedded eps figure

Perfil sanguíneo e peso de órgãos internos de bezerros leiteiros criados em diferentes sistemas de aleitamento

Objetivou-se avaliar o perfil sanguíneo e o tamanho absoluto e relativo dos órgãos internos de bezerros em sistema de aleitamento convencional ou fracionado. Foram utilizadas 10 fêmeas, com peso corporal inicial médio de 37,53 kg (±2,36) e 12 machos com peso corporal médio de 81,6 kg (±8,6), ambos da raça Holandesa. O aleitamento convencional constituiu-se de quatro litros de leite fornecidos diariamente durante 54 dias de avaliação e o fracionado, de seis litros do 6º ao 25º dias de idade, quatro litros do 26º ao 45º dias de idade e dois litros do 46º ao 59º dias de idade, além de concentrado, feno de Cynodon sp., água e suplemento mineral fornecidos ad libitum. O delineamento experimental foi inteiramente ao acaso, com cinco repetições para os parâmetros sanguíneos e seis repetições para o desenvolvimento dos órgãos internos. As coletas de sangue foram realizadas nas fêmeas nos dias sete, 21, 28, 42, 49 e 56 de idade. Para a avaliação dos órgãos internos os machos foram abatidos aos dois meses de idade, após jejum de 16 horas. Não foram observadas diferenças para os valores de proteínas totais, albumina, globulina, creatinina, ureia, colesterol e β-hidroxibutirato nas idades avaliadas (p>0,05). Entretanto, para a concentração de glicose houve interação entre os sistemas de aleitamento e os períodos avaliados, podendo ser observado que com 21 dias de idade a concentração foi maior nas bezerras mantidas em sistema fracionado, quando comparadas aos animais do grupo convencional. O sistema de aleitamento não alterou o peso corporal final, peso corporal final vazio e o peso dos órgãos internos, exceto para o coração, demonstrando que o sistema de aleitamento fracionado não altera as avaliações dos órgãos internos

Conceitos culturais e a experiência dolorosa Cultural aspects and the pain experience

Este estudo objetivou verificar influência de fatores culturais na expressão do sintoma álgico. Foi baseado na avaliação de 57 pacientes com doença oncológica avançada, atendidos no serviço de radioterapia de um hospital geral, público e de ensino que experienciaram dor na semana anterior à entrevista. A duração média do quadro álgico foi 10 meses. A dor foi moderada na maioria dos doentes e intensa em cerca de 1/ 5 deles. Observou-se que concepções culturais errôneas dos doentes acerca da incontrolabilidade da dor no câncer e de que recebiam remédios em demasia, correlacionaram-se à, dor de maior intensidade (p<0,05). Este estudo mostrou que crenças errôneas relativas à dor oncológica e analgesia associaram-se a dores mais intensas.<br>The aim of this investigation was to examine the influence of cultural factors in the pain intensity. Patients presenting advanced cancer and pain, under treatment in an outpatients oncologic unit were evaluated. Pain and cultural factors were evaluated through interviews based on the use of instruments adapted to portuguese language: Patient Pain Questionnaire. Pain lasted 10 months as an average. It was moderate in the majority of patients and severe in 1/5 of them. Cultural misconceptions about the impossibility of cancer pain control and the idea that doctors prescribe excessive amount of analgesics, were correlated with higher intensities of pain (p<0,05)