Differential expression of components of the cardiomyocyte adrenomedullin/intermedin receptor system following blood pressure reduction in nitric oxide-deficient hypertension.

Adrenomedullin (AM) and intermedin (IMD; adrenomedulln-2) are vasodilator peptides related to calcitonin gene-related peptide (CGRP). The actions of these peptides are mediated by the calcitonin receptor-like receptor (CLR) in association with one of three receptor activity-modifying proteins. CGRP is selective for CLR/receptor activity modifying protein (RAMP)1, AM for CLR/RAMP2 and -3, and IMD acts at both CGRP and AM receptors. In a model of pressure overload induced by inhibition of nitric-oxide synthase, up-regulation of AM was observed previously in cardiomyocytes demonstrating a hypertrophic phenotype. The current objective was to examine the effects of blood pressure reduction on cardiomyocyte expression of AM and IMD and their receptor components. Nomega-nitro-L-arginine methyl ester (L-NAME) (35 mg/kg/day) was administered to rats for 8 weeks, with or without concurrent administration of hydralazine (50 mg/kg/day) and hydrochlorothiazide (7.5 mg/kg/day). In left ventricular cardiomyocytes from L-NAME-treated rats, increases (-fold) in mRNA expression were 1.6 (preproAM), 8.4 (preproIMD), 3.4 (CLR), 4.1 (RAMP1), 2.8 (RAMP2), and 4.4 (RAMP3). Hydralazine/hydrochlorothiazide normalized systolic blood pressure (BP) and abolished mRNA up-regulation of hypertrophic markers sk-alpha-actin and BNP and of preproAM, CLR, RAMP2, and RAMP3 but did not normalize cardiomyocyte width nor preproIMD or RAMP1 mRNA expression. The robust increase in IMD expression indicates an important role for this peptide in the cardiac pathology of this model but, unlike AM, IMD is not associated with pressure overload upon the myocardium. The concordance of IMD and RAMP1 up-regulation indicates a CGRP-type receptor action; considering also a lack of response to BP reduction, IMD may, like CGRP, have an anti-ischemic function.

Dried blood spot liquid chromatography assay for therapeutic drug monitoring of metformin

The use of blood spot collection cards is a simple way to obtain specimens for analysis of drugs for the purpose of therapeutic drug monitoring, assessing adherence to medications and preventing toxicity in routine clinical setting. We describe the development and validation of a microanalytical technique for the determination of metformin from dried blood spots. The method is based on reversed phase high-performance liquid chromatography with ultraviolet detection. Drug recovery in the developed method was found to be more than 84%. The limits of detection and quantification were calculated to be to be 90 and 150 ng/ml, respectively. The intraday and interday precision (measured by CV%) was always less than 9%. The accuracy (measured by relative error, %) was always less than 12%. Stability analysis showed that metformin is stable for at least 2 months when stored at -70 degrees C. The small volume of blood required (10 mu L), combined with the simplicity of the analytical technique makes this a useful procedure for monitoring metformin concentrations in routine clinical settings. The method is currently being applied to the analysis of blood spots taken from diabetic patients to assess adherence to medications and relationship between metformin level and metabolic control of diabetes. (c) 2006 Elsevier B.V. All rights reserved.

Allogenic Peripheral Blood Derived Mesenchymal Stem Cells (MSCs) Enhance Bone Regeneration in Rabbit Ulna Critical-Sized Bone Defect Model

Mesenchymal stem cells (MSCs) were demonstrated to exist within peripheral blood (PB) of several mammalian species including human, guinea pig, mice, rat, and rabbit. Whether or not the PB derived MSCs (PBMSCs) could enhance the regeneration of large bone defects have not been reported. In this study, rabbit MSCs were obtained from mononuclear cells (MNCs) cultures of both the PB and bone marrow (BM) origin. The number of PBMSCs was relatively lower, with the colony forming efficiency (CFE) ranging from 1.2-13 per million MNCs. Under specific inductive conditions, PBMSCs differentiated into osteoblasts, chondrocytes, and adipocytes, showing multi- differentiation ability similar to BMMSCs. Bilateral 20 mm critical-sized bone defects were created in the ulnae of twelve 6-month old New Zealand white rabbits. The defects were treated with allogenic PBMSCs/Skelite (porous calcium phosphate resorbable substitute), BMMSCs/Skelite, PBMNCs/Skelite, Skelite alone and left empty for 12 weeks. Bone regeneration was evaluated by serial radiography, peripheral quantitative computed tomography (pQCT), and histological examinations. The x-ray scores and the pQCT total bone mineral density in the PBMSCs/Skelite and BMMSCs/Skelite treated groups were significantly greater than those of the PBMNCs/Skelite and Skelite alone groups (p

The endogenous granulocyte colony-stimulating factor response following autologous peripheral blood stem cell transplantation is inpaired in patients with myeloma

Granulocyte colony-stimulating factor (G-CSF) levels were studied in 23 patients (10 myeloma, 13 relapsed Hodgkin's disease, non-Hodgkin's lymphoma or germ cell tumours), post autologous peripheral blood stem cell transplantation (PBSCT). The two groups had similar previous chemotherapy and numbers of CD34+ cells transplanted. All patients received G-CSF by injection starting 8 d post transplantation. Twenty out of 23 patients showed raised endogenous levels of G-CSF before cytokine administration. Myeloma patients showed significantly lower levels of endogenous G-CSF than the other patients (0.767 versus 3.262 ng/ml, P <0.05). Further rises in G-CSF levels were seen following the administration of exogenous G-CSF which then fell, despite ongoing administration of G-CSF, as neutrophil recovery occurred.

Assessing the Impact of Shipping Vessel Noise on Humpback Whales

The ocean is a hub of noise. Bioacoustic noise, noise from precipitation and wind, and noise from oceanic shelf slides and other geologic processes have occurred consistently as marine species have evolved over time. However, with the discovery of oceanic oil and gas reserves, submarine systems, ship propulsion and the emergence of global trade, anthropogenic sources of sound have added significant quantities of sound to the oceanic system. Shipping has been found to be the largest input of low-frequency anthropogenic noise and Humpback Whales (Megaptera novaengliae), known to be the most vocal marine species, have an auditory sensitivity that falls within the range of frequencies emitted by shipping vessels. As Humpback Whales are heavily dependent on vocalizations, for reasons relatively unconfirmed, a better understanding of why they sing and how their communication is being impacted by vessel noise is critical. Evaluating existing literature both on Humpback behavior and communication, the mechanics of their communication, sound emissions from modern ships, oceanic sound transmission, and studies regarding Humpback's exposure to other sources of low-frequency anthropogenic noise, it is clear that more research is needed to draw any causational conclusions between vessel noise and detrimental impacts on Humpback Whales. With a projected increase in global consumption and vessel traffic, there is an urgent need for further research exploring shipping noise impacts and behavioural alterations of Humpbacks. Existing research has shown changes in Humpback communication when exposed to low-frequency sonar noise, however few studies have been conducted on their communication when in close proximity to shipping vessels. In order for the impacts to be properly assessed, preliminary understanding of humpback communication, their auditory thresholds and more studies between vessel noise exposure and Humpback Whale behavior must be conducted.