Biosynthesis of isovalthine

Liver homogenates could synthetize S-(isopropylcarboxymethyl) glutathione (GSIV) from isovaleric acid and glutathione, and GSIV thus formed was cleaved into L-allo-isovalthine by kidney glutathionase preparation. Isovaleric acid-l-C14 incorporated into GSIV without prior cleavage by the in vitro system. The discrepancy of configuration between urinary and in vitro synthesized isovalthine was discussed.</p

Emotional Modification of the Cardiorespiratory Regulation System

AbstractOur daily life is not solely composed of a calm resting state but is rather full of perturbations that induce active states such as moving, eating, communicating, and so on. During such active conditions, cardiorespiratory regulation should be adjusted according to the body's demand, which differs from that during a resting state, by modulating or resetting the operating point. To explore the neural mechanisms of state-dependent adjustment of central autonomic regulation, we focused on the stress-induced defense (fight-or-flight) response because stressors induce not only cognitive, emotional and behavioral changes but also autonomic changes. In this mini-review, we summarize our recent discovery using orexin knockout mice and orexin neuron-ablated mice of the possible contribution of orexin, a hypothalamic neuropeptide, in the state-dependent adjustment of central autonomic regulation. The diversity of synaptic control of the cardiovascular and respiratory neurons seems necessary for animals to adapt themselves toward ever-changing life circumstances and behavioral states. The orexin system is likely to work as one of the essential modulators for coordinating circuits controlling autonomic functions and behavior

Proteolysis of insulin-like growth factor binding proteins (IGFBPs) by calpain

Calpains are non-lysosomal, Ca2+-dependent cysteine proteases, which are ubiquitously distributed across cell types and vertebrate species. The rules that govern calpain specificity have not yet been determined. To elucidate the cleavage pattern of calpains, we carried out calpain-induced proteolytic studies on the insulin-like growth factor binding proteins IGFBP-4 and -5. Proteolysis of IGFBPs is well characterized in numerous reports. Our results show that calpain cleavage sites are in the non-conserved unstructured regions of the IGFBPs. Compilation of the calpain-induced proteolytic cleavage sites in several proteins reported in the literature, together with our present study, has not revealed clear preferences for amino acid sequences. We therefore conclude that calpains seem not to recognize amino acid sequences, but instead cleave with low sequence specificity at unstructured or solvent-exposed fragments that connect folded, stable domains of target proteins

Quantitative analysis of thrombopoietin receptors on human megakaryocytes

AbstractThrombopoietin (TPO), or c-MPL ligand, is the primary regulator of megakaryocyte and platelet production. TPO receptors expressed on human megakaryocytes derived from peripheral blood (PB) and cord blood (CB) progenitors cultured in the presence of TPO have now been analyzed quantitatively. Like those on human PB platelets, TPO receptors on the cultured megakaryocytes exhibited a molecular mass of approximately 80 kDa. Various characteristics of PB- and CB-derived megakaryocytes indicated that the former were more mature than the latter. Both PB- and CB-derived megakaryocytes expressed a single class of high-affinity TPO receptors, with 1933±772 (n=3) and 184±48 (n=4) sites per cell, respectively. These data indicate that the number of TPO receptors on human megakaryocytes increases with cell maturation

The Role of Echocardiography in the Management of Patients Undergoing a Ventricular Assist Device Implantation and/or Transplantation

Heart transplantation (HTx) is a curative treatment for patients with advanced heart failure (HF); however, since transplant opportunities are severely limited due to donor shortage, the left ventricular assist device (LVAD) has become a standard therapy for patients awaiting HTx. The role of echocardiography as a primary imaging modality to monitor the allograft function in transplant recipients as well as to optimize LVAD settings in LVAD recipients has been expanding. The purpose of this review is to highlight the clinical role of echocardiography in the management of patients undergoing LVAD implantation and/or HTx. In particular, we overview (1) how to detect LVAD malfunction and device-associated complication in LVAD recipients and (2) echocardiographic assessments of cardiac allograft rejection in transplant recipients

The integrated ultradian organization of behavior and physiology in mice and the contribution of orexin to the ultradian patterning

© 2016 IBRO. Published by Elsevier Ltd. All rights reserved. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Our series of rat experiments have shown that locomotor activity, arousal level, body and brown adipose tissue temperatures, heart rate and arterial pressure increase episodically in an integrated manner approximately every 100 min (ultradian manner). Although it has been proposed that the integrated ultradian pattern is a fundamental biological rhythm across species, there are no reports of the integrated ultradian pattern in species other than rats. The aim of the present study was to establish a mouse model using simultaneous recording of locomotor activity, eating behavior, body temperature, heart rate and arousal in order to determine whether their behavior and physiology are organized in an ultradian manner in normal (wild-type) mice. We also incorporated the same recording in prepro-orexin knockout (ORX-KO) mice to reveal the role of orexin in the brain mechanisms underlying ultradian patterning. The orexin system is one of the key conductors required for coordinating autonomic functions and behaviors, and thus may contribute to ultradian patterning. In wild-type mice, locomotor activity, arousal level, body temperature and heart rate increased episodically every 93 ± 18 min (n = 8) during 24 h. Eating was integrated into the ultradian pattern, commencing 23 ± 4 min (n = 8) after the onset of an electroencephalogram (EEG) ultradian episode. The integrated ultradian pattern in wild-type mice is very similar to that observed in rats. In ORX-KO mice, the ultradian episodic changes in locomotor activity, EEG arousal indices and body temperature were significantly attenuated, but the ultradian patterning was preserved. Our findings support the view that the ultradian pattern is common across species. The present results also suggest that orexin contributes to driving ultradian episodic changes, however, this neuropeptide is not essential for the generation of the ultradian pattern

Improving efficiency of supercontinuum generation in photonic crystal fibers by direct degenerate four-wave-mixing

We numerically study supercontinuum (SC) generation in photonic crystal fibers pumped with low-power 30-ps pulses close to the zero dispersion wavelength 647nm. We show how the efficiency is significantly improved by designing the dispersion to allow widely separated spectral lines generated by degenerate four-wave-mixing (FWM) directly from the pump to broaden and merge. By proper modification of the dispersion profile the generation of additional FWM Stokes and anti-Stokes lines results in efficient generation of an 800nm wide SC. Simulations show that the predicted efficient SC generation is more robust and can survive fiber imperfections modelled as random fluctuations of the dispersion coefficients along the fiber length.Comment: Submited to Journal of the Optical Society of America B on 16 September 200