(18)F-labeled rhodamines as potential myocardial perfusion agents: comparison of pharmacokinetic properties of several rhodamines.

INTRODUCTION: We recently reported the development of the [(18)F]fluorodiethylene glycol ester of rhodamine B as a potential positron emission tomography (PET) tracer for myocardial perfusion imaging (MPI). This compound was developed by optimizing the ester moiety on the rhodamine B core, and its pharmacokinetic properties were found to be superior to those of the prototype ethyl ester. The goal of the present study was to optimize the rhodamine core while retaining the fluorodiethyleneglycol ester prosthetic group. METHODS: A series of different rhodamine cores (rhodamine 6G, rhodamine 101, and tetramethylrhodamine) were labeled with (18)F using the corresponding rhodamine lactones as the precursors and [(18)F]fluorodiethylene glycol ester as the prosthetic group. The compounds were purified by semipreparative HPLC, and their biodistribution was measured in rats. Additionally, the uptake of the compounds was evaluated in isolated rat cardiomyocytes. RESULTS: As was the case with the different prosthetic groups, we found that the rhodamine core has a significant effect on the in vitro and in vivo properties of this series of compounds. Of the rhodamines evaluated to date, the pharmacologic properties of the (18)F-labeled diethylene glycol ester of rhodamine 6G are superior to those of the (18)F-labeled diethylene glycol esters of rhodamine B, rhodamine 101, and tetramethylrhodamine. As with (18)F-labeled rhodamine B, [(18)F]rhodamine 6G was observed to localize in the mitochondria of isolated rat cardiomyocytes. CONCLUSIONS: Based on these results, the (18)F-labeled diethylene glycol ester of rhodamine 6G is the most promising potential PET MPI radiopharmaceutical of those that have evaluated to date, and we are now preparing to carry out first-in-human clinical studies with this compound.

Use of [18F]FDG Positron Emission Tomography to Monitor the Development of Cardiac Allograft Rejection.

BACKGROUND: Positron emission tomography (PET) has the potential to be a specific, sensitive and quantitative diagnostic test for transplant rejection. To test this hypothesis, we evaluated F-labeled fluorodeoxyglucose ([F]FDG) and N-labeled ammonia ([N]NH3) small animal PET imaging in a well-established murine cardiac rejection model. METHODS: Heterotopic transplants were performed using minor major histocompatibility complex-mismatched B6.C-H2 donor hearts in C57BL/6(H-2) recipients. C57BL/6 donor hearts into C57BL/6 recipients served as isograft controls. [F]FDG PET imaging was performed weekly between posttransplant days 7 and 42, and the percent injected dose was computed for each graft. [N]NH3 imaging was performed to evaluate myocardial perfusion. RESULTS: There was a significant increase in [F]FDG uptake in allografts from day 14 to day 21 (1.6% to 5.2%; P < 0.001) and uptake in allografts was significantly increased on posttransplant days 21 (5.2% vs 0.9%; P = 0.005) and 28 (4.8% vs 0.9%; P = 0.006) compared to isograft controls. Furthermore, [F]FDG uptake correlated with an increase in rejection grade within allografts between days 14 and 28 after transplantation. Finally, the uptake of [N]NH3 was significantly lower relative to the native heart in allografts with chronic vasculopathy compared to isograft controls on day 28 (P = 0.01). CONCLUSIONS: PET imaging with [F]FDG can be used after transplantation to monitor the evolution of rejection. Decreased uptake of [N]NH3 in rejecting allografts may be reflective of decreased myocardial blood flow. These data suggest that combined [F]FDG and [N]NH3 PET imaging could be used as a noninvasive, quantitative technique for serial monitoring of allograft rejection and has potential application in human transplant recipients.

Biological characterization of F-18-labeled rhodamine B, a potential positron emission tomography perfusion tracer.

INTRODUCTION: Myocardial infarction is the leading cause of death in western countries, and positron emission tomography (PET) plays an increasing role in the diagnosis and treatment planning for this disease. However, the absence of an (18)F-labeled PET myocardial perfusion tracer hampers the widespread use of PET in myocardial perfusion imaging (MPI). We recently reported a potential MPI agent based on (18)F-labeled rhodamine B. The goal of this study was to more completely define the biological properties of (18)F-labeled rhodamine B with respect to uptake and localization in an animal model of myocardial infarction and to evaluate the uptake (18)F-labeled rhodamine B by cardiomyocytes. METHODS: A total of 12 female Sprague Dawley rats with a permanent ligation of the left anterior descending artery (LAD) were studied with small-animal PET. The animals were injected with 100-150 µCi of (18)F-labeled rhodamine B diethylene glycol ester ([(18)F]RhoBDEGF) and imaged two days before ligation. The animals were imaged again two to ten days post-ligation. After the post-surgery scans, the animals were euthanized and the hearts were sectioned into 1mm slices and myocardial infarct size was determined by phosphorimaging and 2,3,5-triphenyltetrazolium chloride staining (TTC). In addition, the uptake of [(18)F]RhoBDEGF in isolated rat neonatal cardiomyocytes was determined by fluorescence microscopy. RESULTS: Small-animal PET showed intense and uniform uptake of [(18)F]RhoBDEGF throughout the myocardium in healthy rats. After LAD ligation, well defined perfusion defects were observed in the PET images. The defect size was highly correlated with the infarct size as determined ex vivo by phosphorimaging and TTC staining. In vitro, [(18)F]RhoBDEGF was rapidly internalized into rat cardiomyocytes with ~40 % of the initial activity internalized within the 60 min incubation time. Fluorescence microscopy clearly demonstrated localization of [(18)F]RhoBDEGF in the mitochondria of rat cardiomyocytes. CONCLUSION: Fluorine-18-labeled rhodamine B diethylene glycol ester ([(18)F]RhoBDEGF) provides excellent image quality and clear delineation of myocardial infarcts in a rat infarct model. In vitro studies demonstrate localization of the tracer in the mitochondria of cardiac myocytes. In combination, these results support the continued evaluation of this tracer for the PET assessment of myocardial perfusion.

Effect of the prosthetic group on the pharmacologic properties of 18F-labeled rhodamine B, a potential myocardial perfusion agent for positron emission tomography (PET).

We recently reported the development of the 2-[(18)F]fluoroethyl ester of rhodamine B as a potential positron emission tomography (PET) tracer for myocardial perfusion imaging. This compound, which was prepared using a [(18)F]fluoroethyl prosthetic group, has significant uptake in the myocardium in rats but also demonstrates relatively high liver uptake and is rapidly hydrolyzed in vivo in mice. We have now prepared (18)F-labeled rhodamine B using three additional prosthetic groups (propyl, diethylene glycol, and triethylene glycol) and found that the prosthetic group has a significant effect on the in vitro and in vivo properties of these compounds. Of the esters prepared to date, the diethylene glycol ester is superior in terms of in vitro stability and pharmacokinetics. These observations suggest that the prosthetic group plays a significant role in determining the pharmacological properties of (18)F-labeled compounds. They also support the value of continued investigation of (18)F-labeled rhodamines as PET radiopharmaceuticals for myocardial perfusion imaging.

Identifying ureteropelvic junction obstruction by fluorescence imaging: a comparative study of imaging modalities to assess renal function and degree of obstruction in a mouse model.

PURPOSE: Radiological imaging is the mainstay of diagnosing ureteropelvic junction obstruction. Current established radiological modalities can potentially differentiate the varying degrees of obstruction but they are limited in functionality, applicability and/or comprehensiveness. Of particular concern is that some tests require radiation, which has long-term consequences, especially in children. MATERIALS AND METHODS: We investigated the novel use of Genhance™ 680 dynamic fluorescence imaging to assess ureteropelvic junction obstruction in 20 mice that underwent partial or complete unilateral ureteral obstruction. Ultrasound, mercaptoacetyltriglycine renography, magnetic resonance imaging and fluorescence imaging were performed. RESULTS: Our model of partial and complete obstruction could be distinguished by ultrasound, mercaptoacetyltriglycine renography and magnetic resonance imaging, and was confirmed by histological analysis. Using fluorescence imaging distinct vascular and urinary parameters were identified in the partial and complete obstruction groups compared to controls. CONCLUSIONS: Fluorescence imaging is a feasible alternative radiological imaging modality to diagnose ureteropelvic junction obstruction. It provides continuous, detailed imaging without the risk of radiation exposure.

Development of an ovine model of pediatric complete heart block.

BACKGROUND: Complete heart block is a significant clinical problem that can limit the quality of life in affected children. To understand the pathophysiology of this condition and provide for development of novel therapies, we sought to establish a large animal model of permanent, pacemaker-dependent atrioventricular block (AVB) that mimics the size and growth characteristics of pediatric patients. MATERIALS AND METHODS: We utilized nine immature lambs weighing 10.5 ± 1.4 kg. After implantation of dual-chamber pacemaker devices with fixed leads, AVB was produced by interrupting His-bundle conduction using radio-frequency ablation at the base of the non-coronary cusp of the aortic valve. Ablations (30 to 60 s in duration) were performed under fluoroscopic guidance with electrophysiological monitoring. Interrogation of pacemakers and electrocardiography (ECG) determined the persistence of heart block. Ovine hearts were also examined immunohistochemically for localization of conduction tissue. RESULTS: AVB was produced in eight animals using an atypical approach from the left side of the heart. One animal died due to ventricular fibrillation during ablation proximal to the tricuspid annulus and one lamb was sacrificed postoperatively due to stroke. Four sheep were kept for long-term follow-up (109.8 ± 32.9 d) and required continuous ventricular pacing attributable to lasting AVB, despite significant increases in body weight and size. CONCLUSIONS: We have created a large animal model of pediatric complete heart block that is stable and technically practicable. We anticipate that this lamb model will allow for advancement of cell-based and other innovative treatments to repair complete heart block in children.

Imaging cancer using PET--the effect of the bifunctional chelator on the biodistribution of a (64)Cu-labeled antibody.

INTRODUCTION: Use of copper radioisotopes in antibody radiolabeling is challenged by reported loss of the radionuclide from the bifunctional chelator used to label the protein. The objective of this study was to investigate the relationship between the thermodynamic stability of the (64)Cu-complexes of five commonly used bifunctional chelators (BFCs) and the biodistribution of an antibody labeled with (64)Cu using these chelators in tumor-bearing mice. METHODS: The chelators [S-2-(aminobenzyl)1,4,7-triazacyclononane-1,4,7-triacetic acid (p-NH(2)-Bn-NOTA): 6-[p-(bromoacetamido)benzyl]-1, 4, 8, 11-tetraazacyclotetradecane-N, N', N'', N'''-tetraacetic acid (BAT-6): S-2-(4-aminobenzyl)-1,4,7,10-tetraazacyclododocane tetraacetic acid (p-NH(2)-Bn-DOTA): 1,4,7,10-tetraazacyclododocane-N, N', N", N"'-tetraacetic acid (DOTA): and 1-N-(4-aminobenzyl)-3,6,10,13,16,19-hexaazabicyclo[6.6.6]eicosane-1,8-diamine (SarAr)] were conjugated to the anti-GD2 antibody ch14.18, and the modified antibody was labeled with (64)Cu and injected into mice bearing subcutaneous human melanoma tumors (M21) (n = 3-5 for each study). Biodistribution data were obtained from positron emission tomography images acquired at 1, 24 and 48 hours post-injection, and at 48 hours post-injection a full ex vivo biodistribution study was carried out. RESULTS: The biodistribution, including tumor targeting, was similar for all the radioimmunoconjugates. At 48 h post-injection, the only statistically significant differences in radionuclide uptake (p < 0.05) were between blood, liver, spleen and kidney. For example, liver uptake of [(64)Cu]ch14.18-p-NH(2)-Bn-NOTA was 4.74 ± 0.77 per cent of the injected dose per gram of tissue (%ID/g), and for [(64)Cu]ch14.18-SarAr was 8.06 ± 0.77 %ID/g. Differences in tumor targeting correlated with variations in tumor size rather than which BFC was used. CONCLUSIONS: The results of this study indicate that differences in the thermodynamic stability of these chelator-Cu(II) complexes were not associated with significant differences in uptake of the tracer by the tumor. However, there were significant differences in tracer concentration in other tissues, including those involved in clearance of the radioimmunoconjugate (e.g., liver and spleen).

Biodistribution and stability studies of [18F]fluoroethylrhodamine B, a potential PET myocardial perfusion agent.

INTRODUCTION: Fluorine-18-labeled rhodamine B was developed as a potential positron emission tomography (PET) tracer for the evaluation of myocardial perfusion, but preliminary studies in mice showed no accumulation in the heart suggesting that it was rapidly hydrolyzed in vivo in mice. A study was therefore undertaken to further evaluate this hypothesis. METHODS: [(18)F]Fluoroethylrhodamine B was equilibrated for 2 h at 37 degrees C in human, rat and mouse serum and in phosphate-buffered saline. Samples were removed periodically and assayed by high-performance liquid chromatography. Based on the results of the stability study, microPET imaging and a biodistribution study were carried out in rats. RESULTS: In vitro stability studies demonstrated that [(18)F]fluoroethylrhodamine B much more stable in rat and human sera than in mouse serum. After 2 h, the compound was >80% intact in rat serum but <30% intact in mouse serum. The microPET imaging and biodistribution studies in rats confirmed this result showing high and persistent tracer accumulation in the myocardium compared with the absence of uptake by the myocardium in mice thereby validating our original hypothesis that (18)F-labeled rhodamines should accumulate in the heart. CONCLUSIONS: [(18)F]Fluoroethylrhodamine B is more stable in rat and human sera than it is in mouse serum. This improved stability is demonstrated by the high uptake of the tracer in the rat heart in comparison to the absence of visible uptake in the mouse heart. These observations suggest that (18)F-labeled rhodamines are promising candidates for more extensive evaluation as PET tracers for the evaluation of myocardial perfusion.

Detection of intestinal inflammation by MicroPET imaging using a (64)Cu-labeled anti-beta(7) integrin antibody.

BACKGROUND: The primary function of integrin beta(7) is the recruitment and retention of lymphocytes to the inflamed gut. The aim of this study was to investigate the possibility of imaging colitis radioimmunodetection by targeting the beta(7) integrin with a radiolabeled antibody. METHODS: FIB504.64, a monoclonal antibody that binds to beta(7) integrin, was conjugated with a bifunctional chelator and labeled with (64)Cu. The antibody (50 microg, 7 MBq) was injected into C57BL/6 mice with experimentally induced colitis (n = 6). MicroPET images were collected at 1, 24, and 48 hours postinjection and the biodistribution was measured at 48 hours by tissue assay. Data were also obtained for a (64)Cu-labeled nonspecific isotype-matched antibody in mice with colitis and (64)Cu-labeled FIB504.64 in healthy mice (n = 5-6). RESULTS: The microPET images showed higher uptake of (64)Cu-labeled FIB504.64 in the gut of mice with colitis than for either of the controls. This observation was confirmed by the 48-hour ex vivo biodistribution data: the percentage of injected dose per gram of tissue (%ID/g +/- SD) (large intestine) colitis mice with (64)Cu-labeled FIB504.64, 6.49 +/- 2.25; control mice with (64)Cu-labeled FIB504.64, 3.64 +/- 1.12; colitis mice, (64)Cu-labeled nonspecific antibody 3.97 +/- 0.48%ID/g (P < 0.05 between groups). CONCLUSIONS: The selective uptake of (64)Cu-labeled FIB504.64 antibody in the gut of animals with colitis suggests that integrin beta(7) may be a promising target for radioimmunodetection of this disease, which would aid diagnosis, assessment, and therapy guidance of this disease.

Synthesis of fluorine-18 labeled rhodamine B: A potential PET myocardial perfusion imaging agent.

There is considerable interest in developing an (18)F-labeled PET myocardial perfusion agent. Rhodamine dyes share several properties with (99m)Tc-MIBI, the most commonly used single-photon myocardial perfusion agent, suggesting that an (18)F-labeled rhodamine dye might prove useful for this application. In addition to being lipophilic cations, like (99m)Tc-MIBI, rhodamine dyes are known to accumulate in the myocardium and are substrates for Pgp, the protein implicated in MDR1 multidrug resistance. As the first step in determining whether (18)F-labeled rhodamines might be useful as myocardial perfusion agents for PET, our objective was to develop synthetic methods for preparing the (18)F-labeled compounds so that they could be evaluated in vivo. Rhodamine B was chosen as the prototype compound for development of the synthesis because the ethyl substituents on the amine moieties of rhodamine B protect them from side reactions, thus eliminating the need to include (and subsequently remove) protecting groups. The 2'-[(18)F]fluoroethyl ester of rhodamine B was synthesized by heating rhodamine B lactone with [(18)F]fluoroethyltosylate in acetonitrile at 165 degrees C for 30min using [(18)F]fluoroethyl tosylate, which was prepared by the reaction of ethyleneglycol ditosylate with Kryptofix 2.2.2, K(2)CO(3), and [(18)F]NaF in acetonitrile for 10min at 90 degrees C. The product was purified by semi-preparative HPLC to produce the 2'-[(18)F]fluoroethylester in >97% radiochemical purity with a specific activity of 1.3GBq/mumol, an isolated decay corrected yield of 35%, and a total synthesis time of 90min.

In utero treatment for bladder outlet obstruction using robot assisted laparoscopic techniques.

PURPOSE: Bladder outlet obstruction can have devastating consequences. Given the poor outcome, intervention in utero has been advocated in an attempt to salvage pulmonary and renal function. We evaluated whether laparoscopic decompression of the obstructed bladder could be performed efficiently by adapting current robot assisted laparoscopic techniques to access the fetus in utero. MATERIALS AND METHODS: At 95 days of gestation 20 fetal sheep underwent ligation of the urethra and urachus. Two to 5 days later robot assisted laparoscopic vesicostomy was performed. Ultrasound of the kidneys and bladder was performed before each procedure. At 135 days of gestation the urinary tract was evaluated to assess the adequacy of bladder decompression and a patent vesicostomy. RESULTS: After 48 hours of undergoing ligation all fetuses had bilateral moderate hydronephrosis and a markedly distended bladder. In the first 10 fetuses vesicostomy could not be completed laparoscopically due to limited visualization. Additional modifications in trocar placement and gas infusion allowed vesicostomy to be completed laparoscopically in the last 8 fetuses in 2.5 to 4 hours. Urinary tract decompression and a patent vesicostomy were observed in all of these fetuses postoperatively. CONCLUSIONS: We developed specific modifications in current robot assisted laparoscopic techniques and instrumentation to allow the treatment of bladder outlet obstruction in utero. This procedure may be performed efficiently and it may provide advantages over conventional surgery for fetal intervention.

Conditional mouse osteosarcoma, dependent on p53 loss and potentiated by loss of Rb, mimics the human disease.

Osteosarcoma is the most common primary malignant tumor of bone. Analysis of familial cancer syndromes and sporadic cases has strongly implicated both p53 and pRb in its pathogenesis; however, the relative contribution of these mutations to the initiation of osteosarcoma is unclear. We describe here the generation and characterization of a genetically engineered mouse model in which all animals develop short latency malignant osteosarcoma. The genetically engineered mouse model is based on osteoblast-restricted deletion of p53 and pRb. Osteosarcoma development is dependent on loss of p53 and potentiated by loss of pRb, revealing a dominance of p53 mutation in the development of osteosarcoma. The model reproduces many of the defining features of human osteosarcoma including cytogenetic complexity and comparable gene expression signatures, histology, and metastatic behavior. Using a novel in silico methodology termed cytogenetic region enrichment analysis, we demonstrate high conservation of gene expression changes between murine osteosarcoma and known cytogentically rearranged loci from human osteosarcoma. Due to the strong similarity between murine osteosarcoma and human osteosarcoma in this model, this should provide a valuable platform for addressing the molecular genetics of osteosarcoma and for developing novel therapeutic strategies.

Robot-assisted laparoscopic ileal bladder augmentation: defining techniques and potential pitfalls.

PURPOSE: Laparoscopic bladder augmentation has been limited because of the extensive suturing required. The use of robot-assisted laparoscopic (RAL) procedures may circumvent this limitation and allow more efficient suturing. The purpose of the study is to define the techniques and the potential pitfalls in performing RAL bladder augmentation in an animal model. MATERIALS AND METHODS: Ten swine underwent RAL bladder augmentation using 20 cm of ileum. In five animals, the bowel anastomosis was performed intracorporeally. In the others, the bowel ends were externalized through one of the ports, and a free-hand bowel anastomosis was performed. The operative time was recorded. The anastomoses were evaluated for patency and leakage. RESULTS: The mean procedure time was 6 hours 44 minutes (range 5 hours 50 min-8 hours 5 min) with a rapid learning curve. We identified minor technical modifications that were helpful, such as placement of "hitch stitches," irrigation of the isolated bowel loop extracorporeally, and leaving the bladder wall attachment intact to maintain bladder suspension. Leakage at the bowel-bowel anastomosis occurred in one animal with use of a stapling technique. Because this could be a potentially fatal complication, we altered our technique to perform the bowel-bowel anastomosis outside the peritoneal cavity. Subsequently, there was no further incidences of bowel leakage, and all anastomoses were patent. The mean bowel-bowel anastomosis time was equivalent to using the two techniques. Leakage at the bowel-bladder anastomosis was seen in two animals, both occurring early in the series. CONCLUSION: RAL bladder augmentation can be safely and efficiently performed. There is a rapid learning curve. We identified minor technical modifications in techniques to help reduce operative time and potential complications. We recommend performing the bowel-bowel anastomosis outside the peritoneum to avoid the risk of leakage. Leakage at the bowel-bladder anastomosis may occur but can be managed with simple catheter drainage.

Young women with diabetes: using Internet communication to create stability during life transitions.

AIMS AND OBJECTIVES: The aim of the current study was to explore and describe the strategies young women with Type 1 diabetes used to manage transitions in their lives. This paper will describe one aspect of the findings of how women with Type 1 diabetes used the Internet to interact with other people with diabetes and create stability in their lives. BACKGROUND: Individuals living with diabetes develop a range of different strategies to create stability in their lives and enhance their well-being. Changing social and emotional conditions during life transitions have a major impact on diabetes management. Although the literature indicates that strategies enabling the individuals to cope with transitions are important, they remain under-researched. DESIGN: Using grounded theory, interviews were conducted with 20 women with Type 1 diabetes. Constant comparative data analysis was used to analyse the data and develop an understanding of how young women with Type 1 diabetes used the Internet to create stability in their lives. FINDINGS: The findings revealed that the women valued their autonomy and being in control of when and to whom they reveal their diabetic status, especially during life transitions and at times of uncertainty. However, during these times they also required health and social information and interacting with other people. One of the women's main strategies in managing transitions was to use Internet chat lines as a way of obtaining information and communicating with others. This strategy gave women a sense of autonomy, enabled them to maintain their anonymity and interact with other people on their own terms. CONCLUSIONS: Having meaningful personal interactions, social support and being able to connect with others were fundamental to the women's well being. Most importantly, preserving autonomy and anonymity during such interactions were integral to the way the women with Type 1 diabetes managed life transitions. RELEVANCE TO CLINICAL PRACTICE: Health professionals need to explore and incorporate Internet communication process or anonymous help lines into their practice as a way to assist people manage their diabetes.

Patient Engagement and Coaching for Health: The PEACH study--a cluster randomised controlled trial using the telephone to coach people with type 2 diabetes to engage with their GPs to improve diabetes care: a study protocol.

BACKGROUND: The PEACH study is based on an innovative 'telephone coaching' program that has been used effectively in a post cardiac event trial. This intervention will be tested in a General Practice setting in a pragmatic trial using existing Practice Nurses (PN) as coaches for people with type 2 diabetes (T2D). Actual clinical care often fails to achieve standards, that are based on evidence that self-management interventions (educational and psychological) and intensive pharmacotherapy improve diabetes control. Telephone coaching in our study focuses on both. This paper describes our study protocol, which aims to test whether goal focused telephone coaching in T2D can improve diabetes control and reduce the treatment gap between guideline based standards and actual clinical practice. METHODS/DESIGN: In a cluster randomised controlled trial, general practices employing Practice Nurses (PNs) are randomly allocated to an intervention or control group. We aim to recruit 546 patients with poorly controlled T2D (HbA1c >7.5%) from 42 General Practices that employ PNs in Melbourne, Australia. PNs from General Practices allocated to the intervention group will be trained in diabetes telephone coaching focusing on biochemical targets addressing both patient self-management and engaging patients to work with their General Practitioners (GPs) to intensify pharmacological treatment according to the study clinical protocol. Patients of intervention group practices will receive 8 telephone coaching sessions and one face-to-face coaching session from existing PNs over 18 months plus usual care and outcomes will be compared to the control group, who will only receive only usual care from their GPs. The primary outcome is HbA1c levels and secondary outcomes include cardiovascular disease risk factors, behavioral risk factors and process of care measures. DISCUSSION: Understanding how to achieve comprehensive treatment of T2D in a General Practice setting is the focus of the PEACH study. This study explores the potential role for PNs to help reduce the treatment and outcomes gap in people with T2D by using telephone coaching. The intervention, if found to be effective, has potential to be sustained and embedded within real world General Practice.

Young women with type 1 diabetes' management of turning points and transitions.

The authors used grounded theory to explore and develop a substantive theory to explain how 20 young women with type 1 diabetes managed their lives when facing turning points and undergoing transitions. The women experienced a basic social problem: being in the grip of blood glucose levels (BGLs), which consisted of three categories: (a) the impact of being susceptible to fluctuating BGLs, (b) the responses of other people to the individual woman's diabetes, and (c) the impact of the individual women's diabetes on other people's lives. The women used a basic social process to overcome the basic social problem by creating stability, which involved using three interconnected subprocesses: forming meaningful relationships, enhancing attentiveness to blood glucose levels, and putting things in perspective. Insights into the processes and strategies used by the women have important implications for provision of care and service delivery.

Ultrasound diagnosis of mouse pregnancy and gestational staging.

Phenotypic analysis of mutant mice is limited by lack of accurate, simple, and nondestructive in utero imaging techniques. This study evaluated the usefulness of ultrasound imaging (US) to stage fetal mouse gestational age (GA) and depict morphologic development. We imaged 16 pregnant CD-1 mice and a total of 92 fetuses with a 15-MHz US transducer from 9.5 d postcoitus (DPC) until 20.5 DPC or delivery. Parameters recorded included gestational sac dimensions, crown-rump length (CRL), biparietal diameter (BPD), thoracoabdominal diameter (TAD), onset of cardiac activity, and morphologic development. At 9.5 d DPC, all gestations appeared as rounded sacs, with a diameter (mean +/- standard error) of 4.4 +/- 1 mm. BPD, CRL, and GA were highly correlated. The following structures were first identifiable at the following GA: cardiac activity, 10.5 DPC; major cardiovascular structures, 11.5 DPC; limb buds, 10.5 DPC; spine, 12.5 DPC; face and skull ossification, 13.5 DPC; rib ossification, 15.5 DPC; hind- and forelimb digits, 15.5 DPC; stomach and urinary bladder, 17.5 DPC; visualization of the rhombencephalic vesicle, 13.5 DPC; and visualization of the lateral ventricles, 14.5 DPC. The echogenic lungs were distinct from the liver as early as 12.5 DPC. The circle of Willis was detectable with color Doppler as early as 13.5 DPC and was easily visualized at 15.5 DPC. We found that US provides accurate, simple staging criteria for fetal mouse gestational development after 9.5 DPC and may be a nondestructive means of documenting phenotypic alterations in mutant mice in utero.

Fetal sheep development on ultrasound and magnetic resonance imaging: a standard for the in utero assessment of models of congenital abnormalities.

OBJECTIVE: To establish normative data for the size, conspicuity, and imaging characteristics of normal developing fetal sheep organs on ultrasound (US) and magnetic resonance (MR) imaging. METHODS: US and MR images of ten normal pregnant sheep, at 40, 65, 90, 115, and 140 gestational days (term = 145 days), were scored for organ conspicuity and imaging characteristics. Imaging biometry was correlated with specimens. Gestational age-based growth parameters were modeled using regression. RESULTS: Imaging biometry showed excellent correlation with specimens. Kidney, bladder, stomach, lung, liver, and spine were seen well from 65 days to term by US. More organs were consistently visible from 90 days to term by MR than by US. Most organ imaging characteristics tended not to change throughout gestation. CONCLUSION: Normal fetal sheep biometry, organ conspicuity, and imaging characteristics are established for US and MR and have potential use for the in utero assessment of sheep models of congenital abnormalities.

Radiation exposure reduction during voiding cystourethrography in a pediatric porcine model of vesicoureteral reflux.

PURPOSE: To compare grid-controlled variable-rate pulsed fluoroscopy (GCPFL) and continuous fluoroscopy (CFL) for the reduction of radiation exposure during voiding cystourethrography (VCUG) in a pediatric porcine model of vesicoureteral reflux. MATERIALS AND METHODS: Institutional animal care and use committee approval was obtained. Vesicoureteral reflux was simulated in four pigs, and 48 VCUG studies were performed (24 with GCPFL, 24 with CFL). VCUG was performed at abdominal girths of 8-10 cm (group 1, simulates human newborn to 6-month-old infant), 12-13 cm (group 2, simulates 2-3-year-old child), and 15-17 cm (group 3, simulates 10-year-old child). An electronic device calculated total radiation exposure during fluoroscopy and image recording. With five-point ordinal scales, VCUG images were scored independently for anatomic conspicuity and overall diagnostic quality by two radiologists (radiologists A and B). An analysis of variance was used to compare radiation exposures and fluoroscopy times between GCPFL and CFL and to determine whether radiation exposure and fluoroscopy time were dependent on the pig's abdominal girth. The Pearson product-moment correlation coefficient was used to assess whether fluoroscopy time was correlated with radiation exposure. Anatomic conspicuity and diagnostic quality scores were compared by means of the Wilcoxon signed rank test. RESULTS: Results of analysis of variance revealed that GCPFL resulted in a significant reduction in total radiation exposure compared with CFL for each of the three groups (P < .05 for each comparison), and this reduction was most marked in the larger animals. There were no significant differences in diagnostic quality of the recorded VCUG images (P > .05). Anatomic conspicuity was not significantly different for groups 2 and 3, but there was a significantly higher score for GCPFL in group 1 for radiologist A (P = .04). CONCLUSION: By using GCPFL in the performance of VCUG in a pediatric porcine model of vesicoureteral reflux, total radiation exposure can be reduced by a factor of 4.6-7.5 lower than with CFL, and diagnostic-quality images can be obtained.

Epinephrine prevents muscle blood flow increases after perineural injection of tetrodotoxin.

BACKGROUND: The local anesthetic properties of tetrodotoxin, a potent naturally occurring sodium channel blocker, have been recently reexamined. It was found that sciatic nerve block duration could be greatly increased and systemic toxicity greatly decreased if epinephrine was injected with tetrodotoxin. The mechanism that underlies epinephrine-mediated prolongation of tetrodotoxin nerve blocks is not known, but indirect evidence suggests that epinephrine may slow the clearance of tetrodotoxin from the site of injection. The authors hypothesized that tetrodotoxin causes vasodilatation at its injection site, which accelerates its systemic uptake, and that this vasodilatation is attenuated by coinjected epinephrine. METHODS: The radiolabeled microsphere technique was used to measure tissue blood flow in anesthetized rats before and after perisciatic injection of tetrodotoxin alone and in combination with epinephrine. RESULTS: Tetrodotoxin, in a dose of 0.1 ml of a 60 microM solution, significantly increased blood flow in perisciatic muscle at the injected side compared with simultaneous contralateral control and ipsilateral preinjection baseline. Tetrodotoxin did not increase blood flow in the sciatic nerve. Coinjection of epinephrine with tetrodotoxin prevented tetrodotoxin-induced increases in perisciatic muscle blood flow over time and did not alter sciatic nerve blood flow. Arterial blood pressure was maintained with this dose of tetrodotoxin, although brain blood flow decreased. Coinjection of epinephrine with tetrodotoxin prevented decreases in brain blood flow. Higher doses of tetrodotoxin produced hypotension. CONCLUSIONS: Vasoconstriction in the perisciatic muscles by epinephrine may contribute to the prolongation of tetrodotoxin-induced sciatic nerve blocks and the reduction of systemic toxicity of tetrodotoxin.