Exposure to chronic hypoxia (CH) induces elevated pulmonary artery pressure/resistance, leading to an eventual maladaptive right ventricular hypertrophy (RVH). Muscle RING finger-1 (MuRF1) is a ...muscle-specific ubiquitin ligase that mediates myocyte atrophy and has been shown to play a role in left ventricular hypertrophy and altered cardiac bioenergetics in pressure overloaded hearts. However, little is known about the contribution of MuRF1 impacting RVH in the setting of CH. Therefore, we hypothesized that MuRF1 deletion would enhance RVH compared to their wild-type littermates, while cardiac-specific overexpression would reduce hypertrophy following CH-induced pulmonary hypertension. We assessed right ventricular systolic pressure (RVSP), right ventricle to left ventricle plus septal weight ratio (RV/LV+S) and hematocrit (Hct) following a 3-wk isobaric CH exposure. Additionally, we conducted dual-isotope SPECT/CT imaging with cardiac function agent 201Tl-chloride and cell death agent 99mTc-annexin V. Predictably, CH induced pulmonary hypertension, measured by increased RVSP, RV/LV+S and Hct in WT mice compared to normoxic WT mice. Normoxic WT and MuRF1-null mice exhibited no significant differences in RVSP, RV/LV+S or Hct. CH-induced increases in RVSP were also similar between WT and MuRF1-null mice; however, RV/LV+S and Hct were significantly elevated in CH-exposed MuRF1-null mice compared to WT. In cardiac-specific MuRF1 overexpressing mice, RV/LV+S increased significantly due to CH exposure, even greater than in WT mice. This remodeling appeared eccentric, maladaptive and led to reduced systemic perfusion. In conclusion, these results are consistent with an atrophic role for MuRF1 regulating the magnitude of right ventricular hypertrophy following CH-induction of pulmonary hypertension.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
FDA cGMP requirements for PET drugs Norenberg, Jeffrey P; Schwarz, Sally; VanBrocklin, Henry
The Journal of nuclear medicine (1978),
05/2011, Letnik:
52, Številka:
5
Journal Article
Recenzirano
Production of research PET drugs under an Investigational New Drug (IND) application or under the authority of an institutional Radioactive Drug Research Committee (RDRC) may follow either the cGMP ...regulations in 21 CFR Part 212 or the current United States Pharmacopeia (USP; 32nd edition) General Chapter tided "Radiopharmaceuticals for Positron Emission Tomography-Compounding."
Context: The current data analysis tools in nuclear medicine have not been used to evaluate intra organ regional deposition patterns of pharmaceutical aerosols in preclinical species. Objective: This ...study evaluates aerosol deposition patterns as a function of particle size in rats and mice using novel image analysis techniques. Materials and Method: Mice and rats were exposed to radiolabeled polydisperse aerosols at 0.5, 1.0, 3.0, and 5.0 µm MMAD followed by SPECT/CT imaging for deposition analysis. Images were quantified for both macro deposition patterns and regional deposition analysis using the LRRI-developed Onion Model. Results: The deposition fraction in both rats and mice was shown to increase as the particle size decreased, with greater lung deposition in rats at all particle sizes. The Onion Model indicated that the smaller particle sizes resulted in increased peripheral deposition. Discussion: These data contrast the commonly used 10% deposition fraction for all aerosols between 1.0 and 5.0 µm and indicate that lung deposition fraction in this range does change with particle size. When compared to historical data, the 1.0, 3.0, and 5.0 µm particles result in similar lung deposition fractions; however, the 0.5 µm lung deposition fraction is markedly different. This is probably caused by the current aerosols that were polydisperse to reflect current pharmaceutical aerosols, while the historical data were generated with monodisperse aerosols. Conclusion: The deposition patterns of aerosols between 0.5 and 5.0 µm showed an increase in both overall and peripheral deposition as the particle size decreased. The Onion Model allows a more complex analysis of regional deposition in preclinical models.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In the present study, the effect of radiolabeling conditions on radiolabeling efficiency and achievable specific activity of a DOTA-conjugated highly-lipophilic peptide containing three disulfide ...cyclization bonds was examined. The peptide is designed to bind specifically (with high affinity) to cell-surface receptor guanylyl cyclase C (GCC), which is universally expressed by colorectal cancer cells. The effect of systematic variation of chemical parameters pH, mass of peptide, acetate buffer concentration (ionic strength), and inclusion of ethanol in the radiolabeling reaction vessel on achievable specific activity and labeling efficiency was examined. In addition, a unique approach to acetone-based elution of 68Ga from an initial cation-exchange pre-concentration column is introduced, which improved radiochemical yield and radiochemical purity. For the evaluation of the acetone-based method, two different post-radiolabeling reverse-phase (C18) approaches to purify the final radiolabeled peptide were tested. These results revealed the potential for peptide degradation via the cleavage of disulfide cyclization bonds to form free thiols when using one of these C18 cartridges. The final optimized procedure enabled radiolabeling efficiency of greater than 99% and specific activity greater than 35 MBq/nmole in less than 30 min. The optimized parameters were amenable to the use of an automated 68Ge/68Ga generator and fluid-handling system for clinical production of the GCC receptor-specific 68GaDOTA-MLN6907 peptide. The chemical characteristics of individual peptides govern the most appropriate radiolabeling conditions for the preparation of radiopharmaceuticals.
•The buffer pH, mass of peptide (concentration), and ethanol concentration are optimized for efficient 68Ga radiolabeling of a GCC specific peptide ligand that contains three disulfide cyclization bonds.•Radiochemical purity of greater than 99% and specific activity of up to 36 MBq/nmole was achieved.•Optimization of the automated synthesis of a 68Ga labeled GCC specific peptide ligand with three disulfide bonds is described.•Degradation of the GCC-specific ligand due to use of a specific C18 purification cartridge type for final purification is found to be associated with breakage of disulfide bonds.
Objective. To characterize shared governance in US schools and colleges of pharmacy and recommend best practices to promote faculty engagement and satisfaction.
Findings. The literature review ...revealed only one study on governance in a pharmacy school and some data from an AACP Faculty Survey. Of the 926 faculty members who responded to the survey, the majority were satisfied or very satisfied with faculty governance (64%) and the level of input into faculty governance (63%) at their school. Faculty members in administrative positions and those at public institutions were more satisfied with governance. The forum resulted in the development of five themes: establish a clear vision of governance in all areas; ensure that faculty members are aware of their roles and responsibilities within the governance structure; ensure faculty members are able to join committees of interest; recognize and reward faculty contributions to governance; and involve all full-time faculty members in governance, regardless of their tenure status.
Summary. Establishing shared governance within a school or college of pharmacy impacts overall faculty satisfaction and potentially faculty retention.
Atherosclerosis-related morbidity and mortality remain a global concern. Atherosclerotic disease follows a slow and silent progression, and the transition from early-stage lesions to vulnerable ...plaques remains difficult to diagnose. Inflammation is a key component of the development of atherosclerotic plaque and consequent life-threatening complications. This study assessed
In-DANBIRT as an
, noninvasive SPECT/CT imaging probe targeting an inflammatory marker, Lymphocyte Function Associated Antigen-1 (LFA-1), in atherosclerotic plaques.
. Selective binding of
In-DANBIRT was assessed using Sprague-Dawley rats exposed to filtered air and ozone (1 ppm) by inhalation for 4 hours to induce a circulating leukocytosis and neutrophilia in peripheral blood. After 24 hours, whole blood was collected and incubated with radiolabeled DANBIRT (
Ga-DANBIRT and
In-DANBIRT). Isolated cell component smeared slides using cytospin technique were stained with Wright-Giemsa stain. Apolipoprotein E-deficient (apoE
) mice were fed either a normal diet or a high-fat diet (HFD) for 8 weeks. Longitudinal SPECT/CT imaging was performed 3 hours after administration at baseline, 4, and 8 weeks of HFD diet, followed by tissue harvesting for biodistribution, serum lipid analysis, and histology. 3D autoradiography was performed in both groups 24 hours after administration of
In-DANBIRT.
. Increased specific uptake of radiolabeled DANBIRT by neutrophils in the ozone-exposed group was evidenced by the acute immune response due to 4-hour ozone exposure. Molecular imaging performed at 3 hours using SPECT/CT imaging evidenced an exponential longitudinal increase in
In-DANBIRT uptake in atherosclerosis lesions in HFD-fed mice compared to normal-diet-fed mice. Such results were consistent with increased immune response to vascular injury in cardiovascular and also immune tissues, correlated by 24 hours after administration of 3D autoradiography. Histologic analysis confirmed atherosclerotic disease progression with an increased vascular lesion area in HFD-fed mice compared to normal-diet-fed mice.
.
In-DANBIRT is a promising molecular imaging probe to assess inflammation in evolving atheroma and atherosclerotic plaque.
Improvements to contrast media formulations may be an effective way to increase the accuracy and effectiveness of thoracic computed tomography (CT) imaging in disease evaluation. To achieve contrast ...enhancement in the lungs, a relatively large localized concentration of contrast media must be delivered. Inhalation offers a noninvasive alternative to intrapleural injections for local lung delivery, but effective aerosolization may deter successful imaging strategies. Here, NanoCluster technology was applied to N1177, a diatrizoic acid derivative, to formulate low density nanoparticle agglomerates with aerodynamic diameters ≤5 μm. Excipient-free N1177 NanoCluster powders were delivered to rats by insufflation or inhalation and scanned using CT up to 1 h post dose. CT images after inhalation showed a ∼120 (HU) Hounsfield units contrast increase in the lungs, which was more than sufficient contrast for thoracic CT imaging. Lung tissue histology demonstrated that N1177 NanoClusters did not damage the lungs. NanoCluster particle engineering technology offers a novel approach to safely and efficiently disseminate high concentrations of contrast agents to the lung periphery.
Our understanding of estrogen (17β-estradiol, E2) receptor biology has evolved in recent years with the discovery and characterization of a 7-transmembrane-spanning G protein-coupled estrogen ...receptor (GPER/GPR30) and the development of GPER-selective functional chemical probes. GPER is highly expressed in certain breast, endometrial, and ovarian cancers, establishing the importance of noninvasive methods to evaluate GPER expression in vivo. Here, we developed (99m)Tc-labeled GPER ligands to demonstrate the in vivo status of GPER as an estrogen receptor (ER) and for GPER visualization in whole animals. A series of (99m)Tc(I)-labeled nonsteroidal tetrahydro-3H-cyclopentacquinolone derivatives was synthesized utilizing pyridin-2-yl hydrazine and picolylamine chelates. Radioligand receptor binding studies revealed binding affinities in the 10 to 30 nmol/L range. Cell signaling assays previously demonstrated that derivatives retaining a ketone functionality displayed agonist properties, whereas those lacking such a hydrogen bond acceptor were antagonists. In vivo biodistribution and imaging studies performed on mice bearing human endometrial and breast cancer cell xenografts yielded significant tumor uptake (0.4-1.1%ID/g). Blocking studies revealed specific uptake in multiple organs (adrenals, uterus, and mammary tissue), as well as tumor uptake with similar levels of competition by E2 and G-1, a GPER-selective agonist. In conclusion, we synthesized and evaluated a series of first-generation (99m)Tc-labeled GPER-specific radioligands, demonstrating GPER as an estrogen-binding receptor for the first time in vivo using competitive binding principles, and establishing the utility of such ligands as tumor imaging agents. These results warrant further investigation into the role of GPER in estrogen-mediated carcinogenesis and as a target for diagnostic/therapeutic/image-guided drug delivery.
These studies provide a molecular basis to evaluate GPER expression and function as an ER through in vivo imaging.
Study Objective. To compare non–transferrin‐bound iron and markers of oxidative stress after single intravenous doses of iron dextran, sodium ferric gluconate, and iron sucrose.
Design. Prospective, ...open‐label, crossover study.
Setting. University‐affiliated general clinical research center.
Patients. Twelve ambulatory patients undergoing hemodialysis.
Intervention. Patients received 100 mg of intravenous iron dextran, sodium ferric gluconate, and iron sucrose in random sequence, with a 2‐week washout period between treatments.
Measurements and Main Results. Serum samples for transferrin saturation, non–transferrin‐bound iron, and malondialdehyde (MDA; marker of lipid peroxidation) were obtained before (baseline) and 30, 60, 120, and 360 minutes and 2 weeks after each iron infusion. A serum sample for hemeoxygenase‐1 (HO‐1) RNA was obtained at baseline and 360 minutes after infusion. Non–transferrin‐bound iron values were significantly higher 30 minutes after administration of sodium ferric gluconate and iron sucrose compared with iron dextran (mean ± SEM 10.1 ± 2.2, 3.8 ± 0.8, and 0.23 ± 0.1 μM, respectively, p<0.001 for sodium ferric gluconate vs iron dextran, p=0.002 for iron sucrose vs iron dextran). A significant positive correlation was noted between transferrin saturation and the presence of non–trans‐ferrin‐bound iron for sodium ferric gluconate and iron sucrose (r2=0.37 and 0.45, respectively, p<0.001) but not for iron dextran (r2= 0.09). After sodium ferric gluconate, significantly more samples showed increases in MDA levels from baseline compared with iron sucrose and iron dextran (p=0.006); these increased levels were associated with the presence of non–transferrin‐bound iron, baseline transferrin saturation above 30%, baseline transferrin levels below 180 mg/dl, and ferritin levels above 500 ng/ml (p<0.05). However, only a transferrin level below 180 mg/dl was independently associated (odds ratio 4.8, 95% confidence interval 1.2–15.3).
Conclusion. Iron sucrose and sodium ferric gluconate were associated with greater non–transferrin‐bound iron appearance compared with iron dextran. However, only sodium ferric gluconate showed significant increases in lipid peroxidation. The relationship between non–transferrin‐bound iron from intravenous iron and oxidative stress warrants further exploration.
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