Leveraging a Safety Event Management System to Improve Organizational Learning and Safety Culture.

BACKGROUND AND OBJECTIVES: Safety event management systems (SEMS) are rich sources of patient safety information, which can be used to improve organizational safety culture. An ideal SEMS can accomplish this when the system is improved with the intention of increasing learning and engagement across the organization. To support a global aim of improving overall patient safety and becoming a highly reliable learning health system, focus was directed toward increasing event review and follow-up completion and using this information to drive resource allocation and improvement efforts. METHODS: A new integrated SEMS was customized, tested, and implemented based on identified organizational need. Revised policies were developed to define expectations for event review and follow-up. The new SEMS incorporated a closed-loop communication process which ensured information from events was shared with the event submitters and facilitated shared learning. The expected impacts, improved event reporting, and follow-up were studied and guided ongoing improvements. RESULTS: After transitioning to a new SEMS, we experienced increased overall reporting by 8.6% and improved event follow-up, demonstrated by documentation on specified system forms, by 53.7%. CONCLUSIONS: By implementing a new, efficient, and standardized SEMS, which decentralized event management processes, the organization saw increased reporting and better engagement with patient safety event review and follow-up. Overall, these results demonstrated a stronger reporting culture, which allowed for local problem solving and improved learning from every event reported. A robust reporting culture positively impacted the overall organizational culture of safety.

Photochemical Activation of Enediyne Warheads: A Potential Tool for Targeted Antitumor Therapy.

Spatial and temporal control over DNA cleavage by photoactivated enediynes can be complemented by additional factors such as the release of internal strain, chelation, pH changes, intramolecular H-bonds, and substituent effects. This review presents design and reactivity of photoactivated enediynes/enynes and analyses the chemical, biological, and photophysical challenges in their applications.

Association between Asthma and Chronic Rhinosinusitis Severity in the Context of Asthma Control.

Objective Comorbid asthma is associated with decreased quality of life (QOL) in chronic rhinosinusitis (CRS). It is unclear whether this association is independent of the patients' clinical asthma status. We therefore sought to determine if asthma is associated with lower QOL in CRS, independent of asthma control. Study Design Cross-sectional cohort study of 350 patients with CRS. Setting Tertiary academic rhinology clinic. Subjects and Methods In total, 350 participants with CRS were recruited and 28.3% were asthmatic. CRS-specific QOL was measured using the 22-item Sinonasal Outcome Test (SNOT-22). Asthma control was assessed with the Asthma Control Test (ACT). General health-related QOL was assessed with the EuroQoL 5-dimensional general health-related quality of life survey visual analog scale (EQ-5D VAS). Associations were sought between SNOT-22 and EQ-5D VAS (dependent variables) and asthma (independent variable), while controlling for ACT. ACT score for patients with CRS without asthma was set at 25 (indicating completely controlled, asymptomatic asthma). Results Comorbid asthma was associated with SNOT-22 (ß = 11.8; 95% confidence interval [CI], 6.2-17.3; P < .001) and EQ-5D VAS (ß = -6.2; 95% CI, -11.2 to -1.3; P = .014). After controlling for ACT, asthma was no longer associated with SNOT-22 ( P = .147) or EQ-5D VAS ( P = .994). Instead, ACT score was associated with SNOT-22 (ß = -2.1; 95% CI, -3.2 to -1.1; P < .001) and EQ-5D VAS (ß = 2.1; 95% CI, 1.1 to 3.0; P < .001). ACT score completely drove the association between asthma and worse QOL. Conclusion Comorbid asthma is not necessarily reflective of decreased QOL in CRS. The association of comorbid asthma with lower QOL in CRS is related to the clinical status (eg, control) of asthma.

Periostin as a Biomarker for Nasal Polyps in Chronic Rhinosinusitis.

Objective Periostin is an extracellular matrix protein that is elevated in the sinonasal tissues of patients with chronic rhinosinusitis (CRS). The purpose of this study was to determine whether serum periostin could serve as a molecular biomarker of nasal polyp burden in sinonasal disease. Study Design Prospective cohort study. Setting Academic medical center. Subjects and Methods Serum periostin levels were measured by ELISA on blood samples collected from patients undergoing sinus surgery for CRS (n = 71), further stratified by phenotype as defined by nasal polyps and asthma. Results were compared with assays performed on control subjects (n = 62). Results Mean serum periostin levels were markedly elevated in patients with CRS versus controls (66.1 ng/mL [95% CI, 51.6-80.6] vs 38.7 ng/mL [95% CI, 34.4-42.9], respectively, P = .004). In addition, mean periostin levels were significantly higher in CRS patients with nasal polyps as compared with those without polyps (94.8 ng/mL [95% CI, 67.3-122.4] vs 41.1 ng/mL [95% CI, 35.2-47.0], respectively, P < .001). Periostin levels did not correlate with sex ( P = .473), smoking history ( P = .748), aspirin-exacerbated respiratory disease status ( P = .136), oral steroid use within 1 month of surgery ( P = .281), use of topical steroid nasal spray ( P = .864), or number of prior sinus operations ( P = .973). Conclusion Serum periostin appears to be a novel molecular biomarker for the presence of nasal polyps and may serve as an indicator of CRS endotypes.

Association between systemic antibiotic and corticosteroid use for chronic rhinosinusitis and quality of life.

OBJECTIVE: We sought to establish the significance of querying chronic rhinosinusitis (CRS) patients about their past CRS-related oral antibiotic and corticosteroid usage by determining the association between these metrics and patients' quality of life (QoL). STUDY DESIGN: Cross-sectional study. METHODS: A total of 157 patients with CRS were prospectively recruited. CRS-specific QoL was measured using the 22-item Sinonasal Outcome Test (SNOT-22). General health-related QoL was measured using the EuroQoL five-dimensional questionnaire visual analog scale. Associations were sought between these measures of QoL and frequency of CRS-related oral antibiotic and corticosteroid usage reported by the participants in the prior 3 and 12 months. RESULTS: More frequent antibiotic and corticosteroid use was significantly associated with worse CRS-specific and general health-related QoL, whether querying medication use over the prior 3 months or over the prior 12 months (P < 0.001 in all cases). The effect size of CRS-related antibiotic use during the prior 3 months on CRS-specific QoL (SNOT-22 score) was significantly greater than for use during the prior 12 months. However, there was no other statistically significant difference in effect size for association between QoL and CRS-related antibiotic or corticosteroid use in the prior 3 months versus prior 12 months. These results were independent of the presence or absence of polyps. CONCLUSION: More frequent past CRS-related oral antibiotic and corticosteroid use, regardless of time period queried (3 months or 12 months) is associated with significant decrease in CRS-specific and general health-related QoL. CRS-related systemic medication use is an important indicator of CRS patients' QOL that easily can be queried and utilized in both clinical and research settings. LEVEL OF EVIDENCE: 2c. Laryngoscope, 128:37-42, 2018.

Association between Nasal Obstruction and Risk of Depression in Chronic Rhinosinusitis.

Objective Chronic rhinosinusitis (CRS) is associated with an increased risk for depression. Since nasal obstruction is a symptom of CRS that is treatable, we sought to characterize its impact on the risk for depression in CRS. Study Design Prospective cross-sectional cohort of 94 patients with CRS. Setting Academic tertiary care rhinology clinic. Subjects and Methods Patients with CRS without vasculitis, cystic fibrosis, sarcoidosis, immunodeficiency, or sinonasal malignancy. Risk for depression was assessed with the 2-item Patient Health Questionnaire (PHQ-2) while nasal obstruction was assessed with the Nasal Obstruction Symptom Evaluation (NOSE) instrument. Multivariate logistic regressions were performed to seek association between NOSE and PHQ-2 scores. Analysis of receiver operating characteristic (ROC) curves defined a NOSE threshold for detecting participants with PHQ-2 greater than 1. Results Of the 94 participants, the mean NOSE score was 47.3, and 29.8% of patients had a PHQ-2 score greater than 1. We found an elevated NOSE score was associated with having a PHQ-2 score greater than 1 (adjusted odds ratio, 1.03; 95% CI, 1.01-1.05; P = .001). Alternatively, a 23-point increase in NOSE score was associated with a 1.5-fold increase in PHQ-2 score (adjusted relative risk, 1.02; 95% CI, 1.01-1.03; P < .001). ROC analysis identified an optimal NOSE threshold of 42.5 for detecting participants with PHQ-2 greater than 1, with 82.1% sensitivity and 50.0% specificity. Conclusions The impact of nasal obstruction is associated with an increased risk for depression in patients with CRS. Assessing for severe nasal obstruction may help to identify those patients with CRS with the highest risk for depression.

Smoking: An independent risk factor for lost productivity in chronic rhinosinusitis.

OBJECTIVES/HYPOTHESIS: Chronic rhinosinusitis (CRS) is associated with a significant loss of patient productivity that costs billions of dollars every year. Smoking is associated with worsening sinonasal symptoms, but its effect on lost productivity in CRS patients has yet to be described. Therefore, we sought to determine the association between smoking and productivity in patients with CRS. STUDY DESIGN: Prospective cross-sectional cohort study of 140 patients with CRS. METHODS: Sinonasal symptom severity was measured using the 22-item Sino-Nasal Outcomes Test. Lost productivity was assessed by asking participants how many days of work and/or school they missed in the last 3 months due to CRS. Associations were sought between lost productivity and smoking. RESULTS: Participants missed a mean of 3.0 days (standard deviation = 12.8 days) of work or school due to CRS. Having any history of smoking was associated with 6 days of lost productivity due to CRS (adjusted ß = 6.20, 95% confidence interval [CI]: 0.64 to 11.77, P = .031). Although the number of active smokers in our study cohort was very small (N = 6), we performed a univariate association between smoking status, considering former smokers and active smokers separately, and found that active smoking (ß = 11.75, 95% CI: 2.11 to 21.40, P = .018) had a much larger impact on CRS-related productivity loss than that experienced by former smokers (ß = 4.45, 95% CI: -0.32 to 9.23, P = .070). CONCLUSIONS: Smoking (likely driven by active smoking) is independently associated with missed days of work or school in patients with CRS. Further study is needed to determine whether interventions directed at smoking may impact CRS-related productivity loss. LEVEL OF EVIDENCE: 2c Laryngoscope, 127:1742-1745, 2017.

Long-term glycemic control with hepatic insulin gene therapy in streptozotocin-diabetic mice.

BACKGROUND: Insulin self-administration is burdensome and can produce dangerous hypoglycemia. Insulin gene therapy may improve and simplify the treatment of diabetes mellitus. In rats, metabolically responsive hepatic insulin gene therapy (HIGT) delivered by adenovirus normalizes random blood sugars but with a limited duration. To prolong glycemic control, we delivered a metabolically regulated insulin transgene by adeno-associated virus (AAV). METHODS: We administered increasing doses of self-complementary (SC), pseudotyped AAV8 expressing the (GlRE)3 BP1-2xfur insulin transgene to streptozotocin-diabetic CD-1 mice, and monitored blood sugar and body weight. We also compared responses to intraperitoneal glucose and chow withdrawal, assessed for viral genomes in liver by Southern blotting, and measured hepatic glycogen. RESULTS: Glucose lowering required the combination of SC genomes and AAV capsid pseudotyping. HIGT controlled glycemia in diabetic mice (DM) for > 1 year. However, glycemic responses were variable. Approximately 30% of mice succumbed to hypoglycemia, and approximately 30% of mice again became hyperglycemic. During an intraperitoneal glucose tolerance test, blood sugars declined to normal within 180 min in HIGT-treated DM compared to 90 min in control mice. Hypoglycemia was common among HIGT-treated mice during a 24-h fast. However, HIGT mice lost less weight than either diabetic or nondiabetic controls as a result of increased water intake. HIGT treatment reduced the hepatic glycogen content of fed mice. CONCLUSIONS: Our studies demonstrate the possibility for long-term glycemic correction following AAV-mediated HIGT in mice. However, the dose-response relationship is irregular, and metabolic responsiveness may be less than that observed in rats.

Round window electrocochleography just before cochlear implantation: relationship to word recognition outcomes in adults.

HYPOTHESES: Electrocochleography (ECoG) to acoustic stimuli can differentiate relative degrees of cochlear responsiveness across the population of cochlear implant recipients. The magnitude of the ongoing portion of the ECoG, which includes both hair cell and neural contributions, will correlate with speech outcomes as measured by results on CNC word score tests. BACKGROUND: Postoperative speech outcomes with cochlear implants vary from almost no benefit to near normal comprehension. A factor expected to have a high predictive value is the degree of neural survival. However, speech performance with the implant does not correlate with the number and distribution of surviving ganglion cells when measured postmortem. We will investigate whether ECoG can provide an estimate of cochlear function that helps predict postoperative speech outcomes. METHODS: An electrode was placed at the round window of the ear about to be implanted during implant surgery. Tone bursts were delivered through an insert earphone. Subjects included children (n = 52, 1-18 yr) and postlingually hearing impaired adults (n = 32). Word scores at 6 months were available from 21 adult subjects. RESULTS: Significant responses to sound were recorded from almost all subjects (80/84 or 95%). The ECoG magnitudes spanned more than 50 dB in both children and adults. The distributions of ECoG magnitudes and frequencies were similar between children and adults. The correlation between the ECoG magnitude and word score accounted for 47% of the variance. CONCLUSION: ECoGs with high signal-to-noise ratios can be recorded from almost all implant candidates, including both adult and pediatric populations. In postlingual adults, the ECoG magnitude is more predictive of implant outcomes than other nonsurgical variables such as duration of deafness or degree of residual hearing.

Exposure to harmful housing conditions is common in children admitted to Wellington Hospital.

AIM: To measure the prevalence of exposure to potentially modifiable risk factors in the homes of children hospitalised in Wellington. METHODS: Parents/caregivers of all children admitted to Wellington Public Hospital during a two-week period in July 2012 completed a standardised questionnaire in a face-to-face interview. The questionnaire collected sociodemographic, health and housing condition data. RESULTS: We interviewed parents/caregivers of 106 children, of whom 72% were aged 0-4 years. Respiratory conditions were the most common cause of admission. One third of parents noticed dampness and mould in their house, 50% stated that their house was colder than they preferred during the past month, 20% lived in uninsulated houses, 20% lived in overcrowded houses, and 38% were exposed to second hand smoke (SHS). Compared to New Zealand European (NZE) children, the odds ratios (OR) for Pacific children living in cold and overcrowded houses and being exposed to SHS were 14.0 (95%CI 3.0-66.0), 10.8 (95%CI 2.6-44.1) and 16.0 (95%CI 4.8-55.5) respectively. OR for Maori children living in cold and overcrowded houses and being exposed to SHS were 3.0 (95%CI 1.0-9.0), 6.8 (95%CI 1.6-30.1) and 8.0 (95%CI 2.5-28.6) respectively, compared to NZE children. The OR for children from deprived neighbourhoods (NZDep2006 areas 7-10) living in cold and overcrowded houses and being exposed to SHS were 4.1 (95%CI 1.8-9.6), 5.7 (95%CI 1.9-17.0) and 4.1 (95%CI 1.6-9.6) respectively. CONCLUSIONS: Among children admitted to Wellington Hospital there is a high prevalence of exposure to cold, damp and overcrowded houses and many children are exposed to SHS. Maori and Pacific children and children living in socioeconomically deprived areas are more likely than others to be exposed to these potential risk factors for childhood hospitalisation. This audit of child admissions could be repeated to provide surveillance of modifiable risk factors. A shortened version of the questionnaire could be used to screen children to identify those with harmful exposures in their home environment, provided suitable intervention programmes can be established.

Nitric oxide coupling mediated by iron porphyrins: the N-N bond formation step is facilitated by electrons and a proton.

The coupling of two NO molecules catalyzed by iron porphyrins is of biological importance. We use density functional theory calculations to examine the factors that control the fundamental N-N bond formation step mediated by a single iron porphyrin. The presence of an axial Im ligand, extra electrons, and most importantly a proton, enhance the N-N bond formation step in our model.

A gerbil model of sloping sensorineural hearing loss.

OBJECTIVE: The goal of the overall project is to develop knowledge about cochlear physiology during cochlear implantation and develop procedures for assessing its status during hearing preservation surgery. As a step toward this goal, for this study, we established an animal model of sloping high frequency sensorineural hearing loss that mimics the hearing condition of candidates for combined electric-acoustic stimulation. METHODS: Mongolian gerbils were exposed to band-pass noise using various cutoff frequencies, intensities, exposure times, and survival times. Hearing loss was assessed in far-field recording using preexposure and postexposure auditory brainstem responses (ABRs), and in acute, near-field recordings of the cochlear microphonic and compound action potential from an electrode on the round window. Anatomic loss of hair cells was assessed from dissections. RESULTS: Postexposure ABRs and near-field recordings from the round window revealed sensorineural hearing loss that varied with the overall noise exposure. Loss of hair cells ranged from relatively sparse to large areas of complete absence depending on the noise exposure. Cases with high intensity (120 dB SPL) and long exposure times (3 h) showed sloping patterns of hearing loss with profound high-frequency loss and mild-to-moderate low-frequency loss. These cases showed complete loss of hair cells in the basal cochlea and preserved hair cells in the apical cochlea. The frequencies comprising the slope in the ABRs and the location of the transition zone between preserved and lost hair cells varied according to the cutoff frequency used. CONCLUSION: We were able to reliably induce sensorineural hearing loss and loss of hair cells in the gerbil that is comparable to candidates for hearing preservation surgery. This model can be used to evaluate the effects of electrode introduction in a system with a hearing condition similar to that in cases of hearing preservation operations.

Hepatic insulin gene therapy diminishes liver glycogen despite insulin responsive transcriptional effects in diabetic CD-1 mice.

BACKGROUND: Hepatic insulin gene therapy (HIGT) produces near-normal glycemia in diabetic rats. Hepatic insulin production is expected to stimulate glycogen storage. However, the effect of HIGT on hepatic glycogen metabolism in vivo is unknown. METHODS: After administration of an adenoviral vector capable of inducing glucose responsive insulin production from hepatocytes, we evaluated circulating hormones, cytokines, hepatic gene expression and hepatic glycogen content in diabetic CD-1 mice receiving intravenous streptozotocin. Nondiabetic mice and diabetic mice treated with empty adenovirus served as controls. RESULTS: Peripheral concentrations of human insulin in HIGT mice were less than concentrations of mouse insulin among controls. However, expression of insulin responsive genes in HIGT livers indicated a significant intra-hepatic insulin effect, with expression changes reflecting appropriate responses to fed-fasting transitions. Transcription factors (hepatocyte nuclear factor-4alpha and peroxisome proliferator-activated receptor gamma co-activator-1alpha), as well as target genes (phospho-enol-pyruvate carboxykinase, glucose-6-phosphatase and glucokinase) exhibited insulin responsive expression. Despite producing near normal glycemia, HIGT diminished hepatic glycogen content in both fasted and fed mice. Serum cytokine responses revealed both vector-related (monocyte chemoatractant protein-1, interleukin-6) and transgene specific (resistin, tumor necrosis factor alpha) effects. CONCLUSIONS: HIGT produces low circulating concentrations of insulin, but produces significant intra-hepatic effects on gene expression. Despite controlling hyperglycemia, HIGT exerts unexpected insulin effects on hepatic carbohydrate metabolism. Although the precise mechanisms remain to be determined, they may relate to vector-induced cytokine effects.

A stable hyponitrite-bridged iron porphyrin complex.

The coupling of two nitric oxide (NO) molecules in heme active sites is an important contributor to the conversion of NO to nitrous oxide (N(2)O) by heme-containing enzymes. Several formulations for the presumed heme-Fe{N(2)O(2)}(n-) intermediates have been proposed previously, however, no crystal structures of heme-Fe{N(2)O(2)}(n-) systems have been reported to date. We report the first isolation and characterization of a stable bimetallic hyponitrite iron porphyrin, [(OEP)Fe](2)(mu-N(2)O(2)), prepared from the reaction of [(OEP)Fe](2)(mu-O) with hyponitrous acid. Density functional theoretical calculations were performed on the model compound [(porphine)Fe](2)(mu-N(2)O(2)) to characterize its electronic structure and properties.

Dual role of COUP-TF-interacting protein 2 in epidermal homeostasis and permeability barrier formation.

COUP-TF-interacting protein 2 (CTIP2; also known as Bcl11b) is a transcription factor that plays key roles in the development of the central nervous and immune systems. CTIP2 is also highly expressed in the developing epidermis, and at lower levels in the dermis and in adult skin. Analyses of mice harboring a germline deletion of CTIP2 revealed that the protein plays critical roles in skin during development, particularly in keratinocyte proliferation and late differentiation events, as well as in the development of the epidermal permeability barrier. At the core of all of these actions is a relatively large network of genes, described herein, that is regulated directly or indirectly by CTIP2. The analysis of conditionally null mice, in which expression of CTIP2 was ablated specifically in epidermal keratinocytes, suggests that CTIP2 functions in both cell and non-cell autonomous contexts to exert regulatory influence over multiple phases of skin development, including barrier establishment. Considered together, our results suggest that CTIP2 functions as a top-level regulator of skin morphogenesis.

The antidepressant agomelatine blocks the adverse effects of stress on memory and enables spatial learning to rapidly increase neural cell adhesion molecule (NCAM) expression in the hippocampus of rats.

Agomelatine, a novel antidepressant with established clinical efficacy, acts as a melatonin receptor agonist and 5-HT(2C) receptor antagonist. As stress is a significant risk factor in the development of depression, we sought to determine if chronic agomelatine treatment would block the stress-induced impairment of memory in rats trained in the radial-arm water maze (RAWM), a hippocampus-dependent spatial memory task. Moreover, since neural cell adhesion molecule (NCAM) is known to be critically involved in memory consolidation and synaptic plasticity, we evaluated the effects of agomelatine on NCAM, and polysialylated NCAM (PSA-NCAM) expression in rats given spatial memory training with or without predator stress. Adult male rats were pre-treated with agomelatine (10 mg/kg i.p., daily for 22 d), followed by a single day of RAWM training and memory testing. Rats were given 12 training trials and then they were placed either in their home cages (no stress) or near a cat (predator stress). Thirty minutes later the rats were given a memory test trial followed immediately by brain extraction. We found that: (1) agomelatine blocked the predator stress-induced impairment of spatial memory; (2) agomelatine-treated stressed, as well as non-stressed, rats exhibited a rapid training-induced increase in the expression of synaptic NCAM in the ventral hippocampus; and (3) agomelatine treatment blocked the water-maze training-induced decrease in PSA-NCAM levels in both stressed and non-stressed animals. This work provides novel observations which indicate that agomelatine blocks the adverse effects of stress on hippocampus-dependent memory and activates molecular mechanisms of memory storage in response to a learning experience.

Hepatic insulin gene therapy normalizes diurnal fluctuation of oxidative metabolism in diabetic BB/Wor rats.

Previous studies of hepatic insulin gene therapy (HIGT) focused on glycemic effects of insulin produced from hepatocytes. In this study, we extend the observations of glycemic control with metabolically regulated HIGT to include systemic responses and whole-body metabolism. An insulin transgene was administered with an adenoviral vector [Ad/(GlRE)(3)BP1-2xfur] to livers of BB/Wor rats made diabetic with polyinosinic polycytidilic acid (poly-I:C) (HIGT group), and results compared with nondiabetic controls (non-DM), and diabetic rats receiving different doses of continuous-release insulin implants (DM-low BG and DM-high BG). Blood glucose and growth normalized in HIGT, with lower systemic insulin levels, elevated glucagon, and increased heat production compared with non-DM. Minimal regulation of systemic insulin levels were observed with HIGT, yet the animals maintained normal switching from carbohydrate to lipid metabolism determined by respiratory quotients (RQs), and tolerated 24-hour fasts without severe hypoglycemia. HIGT did not restore serum lipids as we observed increased triglycerides (TGs) and increased free fatty acids, but reduced weight of visceral fat pads despite normal total body fat content and retroperitoneal fat depots. HIGT favorably affects blood glucose, normalizes metabolic switching in diabetic rats, and reduces intra-abdominal fat deposition.

Pharmacokinetics and safety of intravenously administered citrulline in children undergoing congenital heart surgery: potential therapy for postoperative pulmonary hypertension.

OBJECTIVE: Pulmonary hypertension may complicate surgical correction of congenital heart defects, resulting in increased morbidity and mortality. We have previously shown that plasma levels of the nitric oxide precursors citrulline and arginine drop precipitously after congenital cardiac surgery and that oral citrulline supplementation may be protective against the development of pulmonary hypertension. In this study, we assessed the safety and pharmacokinetic profile of intravenous citrulline as a potential therapy for postoperative pulmonary hypertension. METHODS: The initial phase of this investigation was a dose-escalation study of intravenously administered citrulline in infants and children undergoing one of five congenital cardiac surgical procedures (phase 1). The primary safety outcome was a 20% drop in mean arterial blood pressure from the baseline pressure recorded after admission to the intensive care unit. Based on our previous work, the target circulating plasma citrulline trough was 80 to 100 micromol/L. Each patient was given two separate doses of citrulline: the first in the operating room immediately after initiation of cardiopulmonary bypass and the second 4 hours later in the pediatric intensive care unit. Stepwise dose escalations included 50 mg/kg, 100 mg/kg, and 150 mg/kg. After model-dependent pharmacokinetic analysis, we enrolled an additional 9 patients (phase 2) in an optimized dosing protocol that replaced the postoperative dose with a continuous infusion of citrulline at 9 mg/(kg.h) for 48 hours postoperatively. RESULTS: The initial stepwise escalation protocol (phase 1) revealed that an intravenous citrulline dose of 150 mg/kg given after initiation of cardiopulmonary bypass yielded a trough level of in the target range of approximately 80 to 100 micromol/L 4 hours later. The postoperative dose revealed that the clearance of intravenously administered citrulline was 0.6 L/(h.kg), with a volume of distribution of 0.9 L/kg and estimated half-life of 60 minutes. Because of the short half-life, we altered the protocol to replace the postoperative dose with a continuous infusion of 9 mg/(kg.h). An additional 9 patients were studied with this continuous infusion protocol (phase 2). Mean plasma citrulline levels were maintained at approximately 125 mumol/L, with a calculated clearance of 0.52 L/(h.kg). None of the 17 patients studied had a 20% drop in mean arterial blood pressure from baseline. CONCLUSIONS: In this first report of the use of intravenous citrulline in humans, we found citrulline to be both safe and well tolerated in infants and young children undergoing congenital cardiac surgery. Because of the rapid clearance, the optimal dosing regimen was identified as an initial bolus of 150 mg/kg given at the initiation of cardiopulmonary bypass, followed 4 hours later by a postoperative infusion of 9 mg/(kg.h) continued up to 48 hours. Using this regimen, plasma arginine, citrulline, and nitric oxide metabolite levels were well maintained. Intravenous citrulline needs to be studied further as a potential therapy for postoperative pulmonary hypertension.

Adeno-associated viral delivery of a metabolically regulated insulin transgene to hepatocytes.

Transduction with a liver specific, metabolically responsive insulin transgene produces near-normal blood sugars in STZ-diabetic rats. To overcome the limited duration of hepatic transgene expression induced by E1A-deleted adenoviral vectors, we evaluated recombinant adeno-associated virus (rAAV2) for cell type specificity and glucose responsiveness in vitro. Co-infection of AAV2 containing the glucose responsive, liver-specific (GlRE)(3)BP-1 promoter with an empty adenovirus enhanced transduction efficiency, and shortened the duration of transgene expression in HepG2 hepatoma cells, but not primary hepatocytes. However, in the context of rAAV2, (GlRE)(3)BP-1 promoter activity remained confined to cells of hepatocyte lineage, and retained glucose responsiveness. While isolated infection with an insulin expressing rAAV2 failed to attenuate blood sugars in diabetic mice, adenoviral co-administration with the same rAAV2 induced transient, near-normal random blood sugars in a diabetic animal. We conclude that rAAV2 can induce metabolically responsive insulin secretion from hepatocytes in vitro and in vivo. However, alternative AAV serotypes will likely be required to efficiently deliver therapeutic genes to the liver for the treatment of diabetes mellitus.