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Role of Growth Hormone in Regulating Lipolysis, Proteolysis, and Hepatic Glucose Production during Fasting

Alla A. Sakharova, Jeffrey F. Horowitz, Sowmya Surya, Naila Goldenberg, Matthew P. Harber, Kathy Symons, Ariel Barkan

The Journal of Clinical Endocrinology & Metabolism·2008·88 citations

Abstract Context: Fasting is associated with suppressed insulin and augmented GH secretion. The involvement of each mechanism in the regulation of fuel mobilization during fasting is unknown. Objective: To ascertain the role of GH in the regulation of the rates of lipolysis, proteolysis, and hepatic glucose production (HGP) during the physiological daily feed/fast cycle and after 2 d of complete fasting, we used a model of selective GH suppression by the administration of GHRH receptor antagonist (GHRH-A). Design and Setting: We conducted an open label in-patient study in the General Clinical Research Center at the University of Michigan. Participants: Six healthy, nonobese volunteers participated. Main Outcome Measures: We assessed 24-h plasma GH concentration and rates of lipolysis, proteolysis, and HGP using stable isotope techniques after an overnight fast and after 2 d of fasting. Results: GHRH-A suppressed plasma GH by about 65% during the fed state (P = 0.015) but did not alter the rates of lipolysis, proteolysis, or HGP. Fasting for 2 d suppressed plasma insulin concentration by about 80% and elevated plasma GH about 4-fold (both P < 0.01). This was accompanied by a doubling in the rate of lipolysis, an approximately 40% increase in proteolysis, and an approximately 30% decline in HGP (all P < 0.05). Preventing the fasting-induced increase in GH with GHRH-A largely abolished the increase in the rate of lipolysis. GHRH-A also augmented the fasting-induced reduction in HGP but did not alter proteolysis. Conclusions: Endogenous GH plays a very limited metabolic role during the daily feed/fast cycle but is essential for the increased lipolytic rate found with more prolonged fasting.

★ 3.0 (1)

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Accidental Incest, Filial Cannibalism, and Other Peculiar Encounters in Late Imperial Chinese Literature

Tina Lu

2008·2 citations

No abstract available

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The importance of stupidity in scientific research

Martin A. Schwartz

Journal of Cell Science·2008·86 citations

No abstract available

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The Work of Art in the Age of Its Technological Reproducibility

Walter Benjamin

The Work of Art in the Age of Its Technological Reproducibility, and Other Writings on Media·2008·253 citations

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On Upper-Confidence Bound Policies for Non-Stationary Bandit Problems

Aurélien Garivier, Eric Moulines

arXiv·2008

Multi-armed bandit problems are considered as a paradigm of the trade-off between exploring the environment to find profitable actions and exploiting what is already known. In the stationary case, the distributions of the rewards do not change in time, Upper-Confidence Bound (UCB) policies have been shown to be rate optimal. A challenging variant of the MABP is the non-stationary bandit problem where the gambler must decide which arm to play while facing the possibility of a changing environment. In this paper, we consider the situation where the distributions of rewards remain constant over epochs and change at unknown time instants. We analyze two algorithms: the discounted UCB and the sliding-window UCB. We establish for these two algorithms an upper-bound for the expected regret by upper-bounding the expectation of the number of times a suboptimal arm is played. For that purpose, we derive a Hoeffding type inequality for self normalized deviations with a random number of summands. We establish a lower-bound for the regret in presence of abrupt changes in the arms reward distributions. We show that the discounted UCB and the sliding-window UCB both match the lower-bound up to a logarithmic factor.

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Delayed umbilical cord clamping at birth has effects on arterial and venous blood gases and lactate concentrations

N Wiberg, K Källén, P Olofsson

BJOG: An International Journal of Obstetrics & Gynaecology·2008·94 citations

Objective To estimate the influence of delayed umbilical cord clamping at birth on arterial and venous umbilical cord blood gases, bicarbonate (), base excess (BE) and lactate in vigorous newborns.Setting University hospital.Design Prospective observational.Sample Vaginally delivered term newborns.Material and methods Umbilical cord arterial and venous blood was sampled repeatedly every 45 seconds (T0= time zero; T45= 45 seconds, T90= 90 seconds) until the cord pulsations spontaneously ceased in 66 vigorous singletons with cephalic vaginal delivery at 36–42 weeks. Longitudinal comparisons were performed with the Wilcoxon signed‐ranks matched pairs test. Mixed effect models were used to describe the shape of the regression curves.Main outcome measures Longitudinal changes of umbilical cord blood gases and lactate.Results In arterial cord blood, there were significant decreases of pH (7.24–7.21), (18.9–18.1 mmol/l) and BE (−4.85 to −6.14 mmol/l), and significant increases of PaCO2 (7.64–8.07 kPa), PO2 (2.30–2.74 kPa) and lactate (5.3–5.9 mmol/l) from T0 to T90, with the most pronounced changes at T0–T45. Similar changes occurred in venous blood pH (7.32–7.31), (19.54–19.33 mmol/l), BE (−4.93 to −5.19 mmol/l), PaCO2 (5.69–5.81 kPa) and lactate (5.0–5.3 mmol/l), although the changes were smaller and most pronounced at T45–T90. No significant changes were observed in venous PO2.Conclusion Persistent cord pulsations and delayed cord clamping at birth result in significantly different measured values of cord blood acid–base parameters.

★ 2.0 (1)

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Postcolonial Psychoanalysis

Derek Hook

Theory & Psychology·2008·17 citations

J.M. Coetzee's undervalued paper `The Mind of Apartheid' provides a novel means of identifying the preoccupations of a `postcolonial psychoanalysis'. Such an approach to critique offers a tentative psychical-political diagnostics which pertains not only to the affective and discursive dynamics of the colonial sphere as a whole, but also to the subject-/desire-positioning enforced by the pathological colonial relation. Not reducible to the level of textual reading practices, this style of critique makes reference to a series of psychoanalytic concepts (anxiety, fantasy, ambivalence, disavowal) which are never merely figurative and which remain necessarily related to the frame of individual psychical functioning. Ultimately a postcolonial psychoanalysis offers a political analytics of desire that proves useful in engaging both the contents (racial/sexual fantasy) and the dynamics (affective economies, relational subject-positioning) of the psychic life of colonial power. It allows us to identify potential subversions (slippages of colonial authority and identity, the `return effect' of colonial desire) and to bring into focus those process elements (metaphoric condensation, metonymic displacement) that spread and sustain racist ideology and thereby much of the underlying rationality of (post)colonial power.

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Academic clusters: text patterning in published and postgraduate writing

Ken Hyland

International Journal of Applied Linguistics·2008·217 citations

An important component of fluent linguistic production is control of the multi‐word expressions referred to as “clusters”, “chunks” or “bundles”. These are extended collocations which appear more frequently than expected by chance, helping to shape meanings and contributing to our sense of coherence in a text. Clusters seem to present considerable challenges to student writers struggling to make their texts both fluent and assured to readers in their new communities. This paper explores the forms, structures and functions of 4‐word clusters in a corpus of research articles, doctoral dissertations and master's theses of 3.5 million words to show not only that clusters are central to academic discourse but that they offer an important means of differentiating genres, with implications for more evidence‐based instructional practices in advanced writing contexts.

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Newest Papers

Role of Growth Hormone in Regulating Lipolysis, Proteolysis, and Hepatic Glucose Production during Fasting

Accidental Incest, Filial Cannibalism, and Other Peculiar Encounters in Late Imperial Chinese Literature

The importance of stupidity in scientific research

The Work of Art in the Age of Its Technological Reproducibility

On Upper-Confidence Bound Policies for Non-Stationary Bandit Problems

Delayed umbilical cord clamping at birth has effects on arterial and venous blood gases and lactate concentrations

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Academic clusters: text patterning in published and postgraduate writing

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