Reciprocal regulation of brain and muscle Arnt-like protein 1 and peroxisome proliferator-activated receptor alpha defines a novel positive feedback loop in the rodent liver circadian clock.

Recent evidence has emerged that peroxisome proliferator-activated receptor alpha (PPARalpha), which is largely involved in lipid metabolism, can play an important role in connecting circadian biology and metabolism. In the present study, we investigated the mechanisms by which PPARalpha influences the pacemakers acting in the central clock located in the suprachiasmatic nucleus and in the peripheral oscillator of the liver. We demonstrate that PPARalpha plays a specific role in the peripheral circadian control because it is required to maintain the circadian rhythm of the master clock gene brain and muscle Arnt-like protein 1 (bmal1) in vivo. This regulation occurs via a direct binding of PPARalpha on a potential PPARalpha response element located in the bmal1 promoter. Reversely, BMAL1 is an upstream regulator of PPARalpha gene expression. We further demonstrate that fenofibrate induces circadian rhythm of clock gene expression in cell culture and up-regulates hepatic bmal1 in vivo. Together, these results provide evidence for an additional regulatory feedback loop involving BMAL1 and PPARalpha in peripheral clocks.

Intratracheal suctioning in sick preterm infants: prevention of intracranial hypertension and cerebral hypoperfusion by muscle paralysis.

In a prospective nonrandomized study, using each baby as his or her own control, we compared intracranial pressure (anterior fontanel pressure as measured with the Digilab pneumotonometer), cerebral perfusion pressure, BP, heart rate, transcutaneous Po2, and transcutaneous Pco2 before, during, and after endotracheal suctioning, with and without muscle paralysis, in 28 critically ill preterm infants with respiratory distress syndrome. With suctioning, there was a small but significant increase in intracranial pressure in paralyzed patients (from 13.7 [mean] +/- 4.4 mm Hg [SD] to 15.8 +/- 5.2 mm Hg) but a significantly larger (P less than .001) increase when they were not paralyzed (from 12.5 +/- 3.6 to 28.5 +/- 8.3 mm Hg). Suctioning led to a slight increase in BP with (from 45.3 +/- 9.1 to 48.0 +/- 8.7 mm Hg) and without muscle paralysis (from 45.1 +/- 9.4 to 50.0 +/- 11.7 mm Hg); but there was no significant difference between the two groups. The cerebral perfusion pressure in paralyzed infants did not show any significant change before, during, and after suctioning (31.5 +/- 9.1 mm Hg before v 32.0 +/- 8.7 mm Hg during suctioning), but without muscle paralysis cerebral perfusion pressure decreased (P less than .001) from 32.8 +/- 9.7 to 21.3 +/- 13.1 mm Hg. Suctioning induced a slight decrease in mean heart rate and transcutaneous Po2, but pancuronium did not alter these changes. There was no statistical difference in transcutaneous Pco2 before, during, and after suctioning with and without muscle paralysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential energetic response of brain vs. skeletal muscle upon glycemic variations in healthy humans.

The brain regulates all metabolic processes within the organism, and therefore, its energy supply is preserved even during fasting. However, the underlying mechanism is unknown. Here, it is shown, using (31)P-magnetic resonance spectroscopy that during short periods of hypoglycemia and hyperglycemia, the brain can rapidly increase its high-energy phosphate content, whereas there is no change in skeletal muscle. We investigated the key metabolites of high-energy phosphate metabolism as rapidly available energy stores by (31)P MRS in brain and skeletal muscle of 17 healthy men. Measurements were performed at baseline and during dextrose or insulin-induced hyperglycemia and hypoglycemia. During hyperglycemia, phosphocreatine (PCr) concentrations increased significantly in the brain (P = 0.013), while there was a similar trend in the hypopglycemic condition (P = 0.055). Skeletal muscle content remained constant in both conditions (P > 0.1). ANOVA analyses comparing changes from baseline to the respective glycemic plateau in brain (up to +15%) vs. muscle (up to -4%) revealed clear divergent effects in both conditions (P < 0.05). These effects were reflected by PCr/Pi ratio (P < 0.05). Total ATP concentrations revealed the observed divergency only during hyperglycemia (P = 0.018). These data suggest that the brain, in contrast to peripheral organs, can activate some specific mechanisms to modulate its energy status during variations in glucose supply. A disturbance of these mechanisms may have far-reaching implications for metabolic dysregulation associated with obesity or diabetes mellitus.

Esophageal leaks repaired by a muscle onlay approach in the presence of mediastinal sepsis.

BACKGROUND: Nineteen patients were evaluated after closure of intrathoracic esophageal leaks by a pediculated muscle flap onlay repair in the presence of mediastinal and systemic sepsis. METHODS: Intrathoracic esophageal leaks with mediastinitis and systemic sepsis occurred after delayed spontaneous perforations (n = 7) or surgical and endoscopic interventions (n = 12). Six patients presented with fulminant anastomotic leaks. Seven patients had previous attempts to close the leak by surgery (n = 4) or stenting (2) or both (n = 1). The debrided defects measured up to 2 x 12 cm or involved three quarters of the anastomotic circumference and were closed either by a full thickness diaphragmatic flap (n = 13) or a pediculated intrathoracically transposed extrathoracic muscle flap (n = 6). All patients had postoperative contrast esophagography between days 7 and 10 and an endoscopic evaluation 4 to 6 months after surgery. RESULTS: There was no 30-day mortality. During follow-up (4 to 42 months), 16 patients (84%) revealed functional and morphological restoration of the esophagointestinal integrity without further interventions. One patient required serial dilatations for a stricture, and 1 underwent temporary stenting for a persistent fistula; both patients had normal control endoscopy during follow-up. A third patient requiring permanent stenting for stenosis died from gastrointestinal bleeding due to stent erosion during follow-up. CONCLUSIONS: Intrathoracic esophageal leaks may be closed efficiently by a muscle flap onlay approach in the presence of mediastinitis and where a primary repair seems risky. The same holds true for fulminant intrathoracic anastomotic leaks after esophagectomy or other surgical interventions at the gastroesophageal junction.

Aliskiren penetrates adipose and skeletal muscle tissue, and reduces Renin-Angiotensin System activity in obese hypertensive patients

Introduction: Tissue Renin-Angiotensin System activity is increased in obesity and may contribute to obesity-related hypertension and metabolic abnormalities. This open-label pilot study investigated the local effects of Aliskiren in adipose tissue and skeletal muscle.Methods: After a 1-2 week washout, 10 patients with hypertension and abdominal obesity received placebo for 2 weeks, then Aliskiren 300 mg once daily for 4 weeks, followed by a 4-week washout period and then another 4 weeks treatment period with Amlodipine 5 mg once daily. Drug concentrations and Renin-Angiotensin Systembiomarkers were measured in interstitial fluid employing the microdialysis zero-flow method, and in biopsies from abdominal subcutaneous adipose and skeletal muscle.Results: After 4 weeks treatment, microdialysate concentrations (mean±SD) of Aliskiren were 2.4±2.1 ng/ml in adipose tissue, and 7.1±4.2 ng/ml in skeletal muscle. These concentrations were similar to the mean plasma concentration of 8.4±4.4 ng/ml. Tissue concentrations (ng/g) of Aliskiren were 29.0±16.7 ng/g in adipose tissue, and 107.3±68.6 ng/g in skeletal muscle after 4 weeks treatment. Angiotensin II concentrations in microdialysates were below the lower limit of quantification in most patients, but pooled data from two patients suggested that Angiotensin II was reduced by Aliskiren and unchanged by Amlodipine. Aliskiren 300 mg significantly reduced mean plasma Renin activity by 68% and Angiotensin II by 61% (p<0.05 vs. baseline). Amlodipine 5 mg increased plasma Renin activity by 48% (p<0.05 vs. baseline), and non-significantly increased Angiotensin II by 60%. Both treatments increased plasma Renin concentration.Conclusion: Aliskiren 300 mg once daily penetrates adipose and skeletal muscle tissue at concentrations sufficient to reduce tissue Renin-Angiotensin System activity in obese patients with hypertension.

Intra-individual variation in body temperature and pectoral muscle size in nestling Alpine swifts Apus melba in response to an episode of inclement weather

The Alpine swift (Apus melba) forages on insects caught exclusively on the wing, implying that dependent nestlings face acute food shortage in periods of cold and rainy weather. Therefore, there should be strong selection on nestling swifts to evolve physiological strategies to cope with periods of undernutrition. We have investigated intra-individual changes in nestling pectoral muscle and body temperature in response to a 1-week period of inclement weather. The pectoral muscle is the largest reserves of proteins, and nestlings have to devote a large amount of energy in the maintenance of body temperature. The results show that nestling pectoral muscle size and body temperature were significantly reduced during the episode of inclement weather. Assuming that these physiological changes are adaptive, our study suggests that nestling swifts spare energy by a pronounced reduction (up to 18 degrees C) in body temperature and use proteins from the pectoral muscle as a source of extra energy to survive prolonged periods of fasting.

Allelic variation in the VMD2 gene in best disease and age-related macular degeneration.

PURPOSE: To assess the allelic variation of the VMD2 gene in patients with Best disease and age-related macular degeneration (AMD). METHODS: Three hundred twenty-one AMD patients, 192 ethnically similar control subjects, 39 unrelated probands with familial Best disease, and 57 unrelated probands with the ophthalmoscopic findings of Best disease but no family history were screened for sequence variations in the VMD2 gene by single-strand conformation polymorphism (SSCP) analysis. Amplimers showing a bandshift were reamplified and sequenced bidirectionally. In addition, the coding regions of the VMD2 gene were completely sequenced in six probands with familial Best disease who showed no SSCP shift. RESULTS: Forty different probable or possible disease-causing mutations were found in one or more Best disease or AMD patients. Twenty-nine of these variations are novel. Of the 39 probands with familial Best disease, mutations were detected in all 39 (33 by SSCP and 6 by DNA sequencing). SSCP screening of the 57 probands with a clinical diagnosis of Best disease but no family history revealed 16 with mutations. Mutations were found in 5 of 321 AMD patients (1.5%), a fraction that was not significantly greater than in control individuals (0/192, 0%). CONCLUSIONS: Patients with the clinical diagnosis of Best disease are significantly more likely to have a mutation in the VMD2 gene if they also have a positive family history. These findings suggest that a small fraction of patients with the clinical diagnosis of AMD may actually have a late-onset variant of Best disease, whereas at the same time, a considerable fraction of isolated patients with the ophthalmoscopic features of Best disease are probably affected with some other macular disease.

Genotype-phenotype correlation of age-related macular degeneration : influence of complement factor H polymorphism

RAPPORT DE SYNTHESE La dégénérescence maculaire liée à l'âge (DMLA) est une maladie très fréquente qui représente la cause principale de cécité légale chez les sujets de plus de 50 ans en Occident. Bien que l'étiologie exacte de cette affection ne soit pas complètement connue, des facteurs environnementaux et génétiques influencent sa survenue et son évolution. A ce sujet, de récentes recherches ont notamment montré une association marquée à une variante du gène CFH, Y402H. Nous ignorons toutefois si le polymorphisme Y402H est associé à un phénotype particulier de la maladie. Cette étude a pour but d'établir si cette variante du gène CFH est associée à certaines caractéristiques phénotypiques précoces. L'étude porte sur quatre cent vingt patients atteints de DMLA qui ont été phénotypés sur la base de photographie du fond d'oeil (International Classification and Grading system for age- related macular degeneration) et génotypés à partir d'ADN leucocytaire à la recherche de la variante Y402H du gène CFH. Ces données ont ensuite fait l'objet d'une analyse statistique de l'association génotype-phénotype (le génotype de 50 sujets-contrôle a été utilisé pour confirmer l'association du polymorphisme avec la DMLA). Les résultats obtenus, corrigés pour l'âge et le sexe, montrent un odds ratio (OR) de développer une DMLA de 2.95 en présence d'au moins un allèle à risque C et de 9.05 pour les homozygotes CC. Par contre, aucune influence n'est observée sur les stades de la maladie (précoce-tardif)? Une association significative entre le génotype CC et la présence de druses périphériques (p=0.028), ainsi que la localisation centrale des druses (p=0,049) a été mise en évidence. Aucune autre tendance n'a été dégagée concernant les critères restants (taille, surface totale recouverte, localisation nasale des druses) ou les changements pigmentaires. Cette étude a permis de confirmer l'association entre la variante Y4G2H et la DMLA dans la population suisse et de conclure que la variante Y402H du gène CFH présente une association géno-phénotypique pour certaines caractéristiques des druses. Il est probable que d'autres facteurs génétiques encore influencent le phénotype de la DMLA. De nouvelles recherches seront nécessaires pour préciser l'influence de ces autres facteurs génétiques ou environnementaux, en vue d'une meilleure compréhension de la pathogenèse de cette affection, et pour développer des mesures thérapeutiques et prophylactiques adaptées.

Simulated joint and muscle forces in reversed and anatomic shoulder prostheses.

Reversed shoulder prostheses are increasingly being used for the treatment of glenohumeral arthropathy associated with a deficient rotator cuff. These non-anatomical implants attempt to balance the joint forces by means of a semi-constrained articular surface and a medialised centre of rotation. A finite element model was used to compare a reversed prosthesis with an anatomical implant. Active abduction was simulated from 0 degrees to 150 degrees of elevation. With the anatomical prosthesis, the joint force almost reached the equivalence of body weight. The joint force was half this for the reversed prosthesis. The direction of force was much more vertically aligned for the reverse prosthesis, in the first 90 degrees of abduction. With the reversed prosthesis, abduction was possible without rotator cuff muscles and required 20% less deltoid force to achieve it. This force analysis confirms the potential mechanical advantage of reversed prostheses when rotator cuff muscles are deficient.

A novel neuro-muscular marker for the heavy subunit of neurofilament proteins, NF-H, and striated muscle myosin of Xenopus laevis.

A novel monoclonal antibody, M7, is described, that reacts on Western blots with the large subunit of the neurofilament triplet proteins (NF-H) and with striated muscle myosin of Xenopus laevis. Enzymatically digested neurofilament and myosin proteins revealed different immunoreactive peptide fragments on Western blots. Therefore, the antibody must react with immunologically related epitopes common to both proteins. Immunohistochemistry showed staining of large and small axons in CNS and PNS, and nerves could be followed into endplate regions of skeletal muscles. These muscles were characterized by a striated immunostaining of the M-lines. Despite the crossreactivity of M7 with NF-H and muscle myosin, this antibody may be a tool to study innervation of muscle fibers, and to define changes in the neuromuscular organization during early development and metamorphosis of tadpoles.

Characteristics of eyes with secondary loss of visual acuity receiving variable dosing ranibizumab for neovascular age-related macular degeneration.

PURPOSE: The aim of this work is to investigate the characteristics of eyes failing to maintain visual acuity (VA) receiving variable dosing ranibizumab for neovascular age-related macular degeneration (nAMD) after three initial loading doses. METHODS: A consecutive series of patients with nAMD, who, after three loading doses of intravitreal ranibizumab (0.5 mg each), were re-treated for fluid seen on optical coherence tomography. After exclusion of eyes with previous treatment, follow-up less than 12 months, or missed visits, 99 patients were included in the analysis. The influence of baseline characteristics, initial VA response, and central retinal thickness (CRT) fluctuations on the VA stability from month 3 to month 24 were analyzed using subgroups and multiple regression analyses. RESULTS: Mean follow-up duration was 21.3 months (range 12-40 months, 32 patients followed-up for ≥24 months). Secondary loss of VA (loss of five letters or more) after month 3 was seen in 30 patients (mean VA improvement from baseline +5.8 letters at month 3, mean loss from baseline -5.3 letters at month 12 and -9.7 at final visit up to month 24), while 69 patients maintained vision (mean gain +8.9 letters at month 3, +10.4 letters at month 12, and +12.8 letters at final visit up to month 24). Secondary loss of VA was associated with the presence of pigment epithelial detachment (PED) at baseline (p 0.01), but not with baseline fibrosis/atrophy/hemorrhage, CRT fluctuations, or initial VA response. Chart analysis revealed additional individual explanations for the secondary loss of VA, including retinal pigment epithelial tears, progressive fibrosis, and atrophy. CONCLUSIONS: Tissue damage due to degeneration of PED, retinal pigment epithelial tears, progressive fibrosis, progressive atrophy, or massive hemorrhage, appears to be relevant in causing secondary loss of VA despite vascular endothelial growth factor suppression. PED at baseline may represent a risk factor.

In vivo enzymatic activity of acetylCoA synthetase in skeletal muscle revealed by 13C turnover from hyperpolarized [1-13C]acetate to [1-13C]acetylcarnitine

BACKGROUND: Acetate metabolism in skeletal muscle is regulated by acetylCoA synthetase (ACS). The main function of ACS is to provide cells with acetylCoA, a key molecule for numerous metabolic pathways including fatty acid and cholesterol synthesis and the Krebs cycle. METHODS: Hyperpolarized [1-(13)C]acetate prepared via dissolution dynamic nuclear polarization was injected intravenously at different concentrations into rats. The (13)C magnetic resonance signals of [1-(13)C]acetate and [1-(13)C]acetylcarnitine were recorded in vivo for 1min. The kinetic rate constants related to the transformation of acetate into acetylcarnitine were deduced from the 3s time resolution measurements using two approaches, either mathematical modeling or relative metabolite ratios. RESULTS: Although separated by two biochemical transformations, a kinetic analysis of the (13)C label flow from [1-(13)C]acetate to [1-(13)C]acetylcarnitine led to a unique determination of the activity of ACS. The in vivo Michaelis constants for ACS were KM=0.35±0.13mM and Vmax=0.199±0.031μmol/g/min. CONCLUSIONS: The conversion rates from hyperpolarized acetate into acetylcarnitine were quantified in vivo and, although separated by two enzymatic reactions, these rates uniquely defined the activity of ACS. The conversion rates associated with ACS were obtained using two analytical approaches, both methods yielding similar results. GENERAL SIGNIFICANCE: This study demonstrates the feasibility of directly measuring ACS activity in vivo and, since the activity of ACS can be affected by various pathological states such as cancer or diabetes, the proposed method could be used to non-invasively probe metabolic signatures of ACS in diseased tissue.

No implication of thromboxane prostanoid receptors in reactive hyperemia of skin and skeletal muscle in human forearm.

There is evidence that reactive hyperemia (ie, the transient increase of blood flow above resting level after a short period of ischemia) could be negatively modulated by vasoconstrictor prostanoids. The present study tested whether pharmacological blockade of the thromboxane prostanoid receptors with the specific antagonist S18886 (terutroban) would amplify reactive hyperemia in human skin and skeletal muscle. Twenty healthy young male volunteers were enrolled in a randomized, blinded, crossover trial of oral S18886 30 mg/d for 5 days versus placebo. Reactive hyperemia was evaluated in forearm skin and skeletal muscle, after occlusion of the brachial artery with a pneumatic cuff inflated at suprasystolic pressure. Blood flow was measured with laser Doppler imaging (skin) and strain gauge venous occlusion plethysmography (muscle). On the first and last day of each treatment period, recordings of reactive hyperemia were obtained immediately before and 2 hours after drug intake. Whether in forearm muscle or skin, S18886 had no discernible effect on peak postocclusion blood flow, nor on the global hyperemic response as quantified by the area under curve. These results do not support that thromboxane prostanoid receptor activation could exert a moderating influence on reactive hyperemia in human skin and skeletal muscle, at least in young subjects.

Swimming prevents vulnerable atherosclerotic plaque development in hypertensive 2-kidney, 1-clip mice by modulating angiotensin II type 1 receptor expression independently from hemodynamic changes.

Exercise is known to reduce cardiovascular risk. However, its role on atherosclerotic plaque stabilization is unknown. Apolipoprotein E(-/-) mice with vulnerable (2-kidney, 1-clip: angiotensin [Ang] II-dependent hypertension model) or stable atherosclerotic plaques (1-kidney, 1-clip: Ang II-independent hypertension model and normotensive shams) were used for experiments. Mice swam regularly for 5 weeks and were compared with sedentary controls. Exercised 2-kidney, 1-clip mice developed significantly more stable plaques (thinner fibrous cap, decreased media degeneration, layering, macrophage content, and increased smooth muscle cells) than sedentary controls. Exercise did not affect blood pressure. Conversely, swimming significantly reduced aortic Ang II type 1 receptor mRNA levels, whereas Ang II type 2 receptor expression remained unaffected. Sympathetic tone also significantly diminished in exercised 2-kidney, 1-clip mice compared with sedentary ones; renin and aldosterone levels tended to increase. Ang II type 1 downregulation was not accompanied by improved endothelial function, and no difference in balance among T-helper 1, T-helper 2, and T regulatory cells was observed between sedentary and exercised mice. These results show for the first time, in a mouse model of Ang II-mediated vulnerable plaques, that swimming prevents atherosclerosis progression and plaque vulnerability. This benefit is likely mediated by downregulating aortic Ang II type 1 receptor expression independent from any hemodynamic change. Ang II type 1 downregulation may protect the vessel wall from the Ang II proatherogenic effects. Moreover, data presented herein further emphasize the pivotal and blood pressure-independent role of Ang II in atherogenesis.