Tissue pharmacokinetics and pharmacodynamics of AmBisome® (L-AmBis) in uninfected and infected animals and their effects on dosing regimens.

By selecting a unique combination of lipids and amphotericin B, the liposome composition for AmBisome® (L-AmBis) has been optimized resulting in a formulation that is minimally toxic, targets to fungal cell walls, and distributes into and remains for days to weeks in various host tissues at drug levels above the MIC for many fungi. Procedures have been standardized to ensure that large scale production of the drug retains the drug's low toxicity profile, favorable pharmacokinetics and antifungal efficacy. Tissue accumulation and clearance with single or multiple intravenous administration is similar in uninfected and infected animal species, with tissue accumulation being dose-dependent and the liver and spleen retaining the most drug. The efficacy in animals appears to be correlated with drug tissue levels although the amount needed in a given organ varies depending upon the type of infection. The long-term tissue retention of bioactive L-AmBis in different organs suggests that for some indications, prophylactic and intermittent drug dosing would be efficacious reducing the cost and possible toxic side-effects. In addition, preliminary preclinical studies using non-intravenous routes of delivery, such as aerosolized L-AmBis, catheter lock therapy, and intravitreal administration, suggest that alternative routes could possibly provide additional therapeutic applications for this antifungal drug.

Identification of a 10/10 matched donor for patients with an uncommon haplotype is unlikely.

BACKGROUND: Despite over 6 million subjects contributing to the National Marrow Donor Program human leukocyte antigen (HLA) haplotype frequency reference data (HFD), haplotypes cannot be predicted from the HLA assignments of some patients searching for an unrelated donor (URD) in the Be The Match Registry®. We aimed to determine the incidence of these patient searches and whether haplotypes lacking from the HFD can be found among the low-resolution typed URD pool. MATERIALS AND METHODS: New NMDP searches with uncommon patient haplotypes (UPH), defined as a lack of haplotype pairs in any single ethnic group in the HFD based upon HLA-A˜C˜B˜DRB1˜DQB1, were identified. Each search had up to 20 potential 10/10 or 8/8 URDs typed to determine the likelihood of an allele match. RESULTS: The incidence of patient searches without haplotype pairs in a single ethnic group in the HFD was 1.2% (N=144 out of 12,172) and a majority of these patients (117; 81%) had one uncommon haplotype previously uncharacterized in the HFD. Non-White patients had the highest incidence of UPH. Importantly, no patients with UPH had a 10/10 URD identified. The transplant rate among UPH patients was 15%, and a majority of these patients utilized cord blood units as their transplant stem cell source. CONCLUSION: Therefore, the HLA HFD that informs the HapLogic matching algorithm is thorough as UPH patient searches were infrequent. Since such patients are highly unlikely to have a fully 10/10 matched URD identified, this study supports the identification of alternative stem cell sources including cord blood or a mismatched URD early in the search process.

Modelling the cost-effectiveness of adopting risk-stratified approaches to extended screening intervals in the national diabetic retinopathy screening programme in Scotland.

AIMS: To assess the cost-effectiveness of adopting risk-stratified approaches to extended screening intervals in the national diabetic retinopathy screening programme in Scotland. METHODS: A continuous-time hidden Markov model was fitted to national longitudinal screening data to derive transition probabilities between observed non-referable and referable retinopathy states. These were incorporated in a decision model simulating progression, costs and visual acuity outcomes for a synthetic cohort with a covariate distribution matching that of the Scottish diabetic screening population. The cost-effectiveness of adopting extended (2-year) screening for groups with no observed retinopathy was then assessed over a 30-year time horizon. RESULTS: Individuals with a current grade of no retinopathy on two consecutive screening episodes face the lowest risk of progressing to referable disease. For the cohort as a whole, the incremental cost per quality-adjusted life year gained for annual vs. biennial screening ranged from approximately £74 000 (for those with no retinopathy and a prior observed grade of mild or observable background retinopathy) to approximately £232 000 per quality-adjusted life year gained (for those with no retinopathy on two consecutive screening episodes). The corresponding incremental cost-effectiveness ratios in the subgroup with Type 1 diabetes were substantially lower; approximately £22 000 to £85 000 per quality-adjusted life year gained, respectively. CONCLUSIONS: Biennial screening for individuals with diabetes who have no retinopathy is likely to deliver significant savings for a very small increase in the risk of adverse visual acuity and quality of life outcomes. There is greater uncertainty regarding the long-term cost-effectiveness of adopting biennial screening in younger people with Type 1 diabetes.

Use of computer decision support in an antimicrobial stewardship program (ASP).

OBJECTIVE: Document information needs, gaps within the current electronic applications and reports, and workflow interruptions requiring manual information searches that decreased the ability of our antimicrobial stewardship program (ASP) at Intermountain Healthcare (IH) to prospectively audit and provide feedback to clinicians to improve antimicrobial use. METHODS: A framework was used to provide access to patient information contained in the electronic medical record, the enterprise-wide data warehouse, the data-driven alert file and the enterprise-wide encounter file to generate alerts and reports via pagers, emails and through the Centers for Diseases and Control's National Healthcare Surveillance Network. RESULTS: Four new applications were developed and used by ASPs at Intermountain Medical Center (IMC) and Primary Children's Hospital (PCH) based on the design and input from the pharmacists and infectious diseases physicians and the new Center for Diseases Control and Prevention/National Healthcare Safety Network (NHSN) antibiotic utilization specifications. Data from IMC and PCH now show a general decrease in the use of drugs initially targeted by the ASP at both facilities. CONCLUSIONS: To be effective, ASPs need an enormous amount of "timely" information. Members of the ASP at IH report these new applications help them improve antibiotic use by allowing efficient, timely review and effective prioritization of patients receiving antimicrobials in order to optimize patient care.

Toxicity and efficacy differences between liposomal amphotericin B formulations in uninfected and Aspergillus fumigatus infected mice.

Because of the reduced toxicity associated with liposomal amphotericin B preparations, different amphotericin B liposome products have been made. In the present study, we compared the amphotericin B liposomal formulations, AmBisome(®) (AmBi) and Lambin(®) (Lbn), in uninfected and Aspergillus fumigatus infected mice, using several in vitro and in vivo toxicity and efficacy assays. The results showed that the formulations were significantly different, with Lbn 1.6-fold larger than AmBi. Lbn was also more toxic than AmBi based on the RBC potassium release assay and intravenous dosing in uninfected mice given a single 50 mg/kg dose (80% mortality for Lbn vs. 0% for AmBi). Renal tubular changes after intravenous daily dosing for 14 days were seen in uninfected mice given 5 mg/kg Lbn but not with AmBi. Survival following A. fumigatus challenge was 30% for 10 mg/kg Lbn and 60% for 10 mg/kg AmBi. When the BAL and lungs were collected 24 h after the second treatment, AmBi at 10 or 15 mg/kg or 15 mg/kg Lbn lowered the BAL fungal burden significantly vs. the controls (P ≤ 0.05), while there was no difference in lung fungal burden amongst the groups. In contrast, lung histopathology at this same early timepoint showed that AmBi was associated with markedly fewer fungal elements and less lung tissue damage than Lbn. In conclusion, given the differences in size, toxicity, and efficacy, AmBi and Lbn were not physically or functionally comparable, and these differences underscore the need for adequate testing when comparing amphotericin B liposome formulations.

Rates of referable eye disease in the Scottish National Diabetic Retinopathy Screening Programme.

AIMS: Diabetic retinopathy screening aims to detect people at risk of visual loss due to proliferative diabetic retinopathy, but also refers cases of suspected macular oedema (maculopathy). At the introduction of screening, ophthalmology was concerned that referral rates would be unmanageable. We report yield of referable disease by referral reason for the first 5 years of the programme. METHODS: We extracted screening results from a nationwide clinical diabetes database to calculate annual referral rates to ophthalmic clinics. We used logistic regression to examine associations between clinical measures and referable disease. RESULTS: 182 397 people underwent ≥ 1successful retinal screening between 2006 and 2010. The yield of referable eye disease was highest in the first 2 years of screening (7.0% and 6.0%) before stabilising at ∼4.3%. The majority of referrals are due to maculopathy with 73% of referrals in 2010 based on a finding of maculopathy. CONCLUSIONS: The commonest cause for referral is for suspected macular oedema (maculopathy). Referral rates for retinopathy have stabilised, as predicted, at relatively low rates. However, ophthalmology workload continues to rise as new treatment options (ie, monthly intraocular injections) have unexpectedly increased the impact on ophthalmology. A review of the screening referral path for maculopathy may be timely.

Predicted impact of extending the screening interval for diabetic retinopathy: the Scottish Diabetic Retinopathy Screening programme.

AIMS/HYPOTHESIS: The aim of our study was to identify subgroups of patients attending the Scottish Diabetic Retinopathy Screening (DRS) programme who might safely move from annual to two yearly retinopathy screening. METHODS: This was a retrospective cohort study of screening data from the DRS programme collected between 2005 and 2011 for people aged ≥12 years with type 1 or type 2 diabetes in Scotland. We used hidden Markov models to calculate the probabilities of transitions to referable diabetic retinopathy (referable background or proliferative retinopathy) or referable maculopathy. RESULTS: The study included 155,114 individuals with no referable diabetic retinopathy or maculopathy at their first DRS examination and with one or more further DRS examinations. There were 11,275 incident cases of referable diabetic eye disease (9,204 referable maculopathy, 2,071 referable background or proliferative retinopathy). The observed transitions to referable background or proliferative retinopathy were lower for people with no visible retinopathy vs mild background retinopathy at their prior examination (respectively, 1.2% vs 8.1% for type 1 diabetes and 0.6% vs 5.1% for type 2 diabetes). The lowest probability for transitioning to referable background or proliferative retinopathy was among people with two consecutive screens showing no visible retinopathy, where the probability was <0.3% for type 1 and <0.2% for type 2 diabetes at 2 years. CONCLUSIONS/INTERPRETATION: Transition rates to referable diabetic eye disease were lowest among people with type 2 diabetes and two consecutive screens showing no visible retinopathy. If such people had been offered two yearly screening the DRS service would have needed to screen 40% fewer people in 2009.

Diabetic retinopathy at diagnosis of type 2 diabetes in Scotland.

AIMS/HYPOTHESIS: The aim of this study was to examine the prevalence of and risk factors for diabetic retinopathy in people with newly diagnosed type 2 diabetes mellitus, using Scottish national data. METHODS: We identified individuals diagnosed with type 2 diabetes mellitus in Scotland between January 2005 and May 2008 using data from the national diabetes database. We calculated the prevalence of retinopathy and ORs for risk factors associated with retinopathy at first screening. RESULTS: Of the 51,526 people with newly diagnosed type 2 diabetes mellitus identified, 91.4% had been screened by 31 December 2010. The median time to first screening was 315 days (interquartile range [IQR] 111-607 days), but by 2008 the median was 83 days (IQR 51-135 days). The prevalence at first screening of any retinopathy was 19.3%, and for referable retinopathy it was 1.9%. For individuals screened after a year the prevalence of any retinopathy was 20.5% and referable retinopathy was 2.3%. Any retinopathy at screening was associated with male sex (OR 1.19, 95% CI 1.14, 1.25), HbA(1c) (OR 1.07, 95% CI 1.06, 1.08 per 1% [11 mmol/mol] increase), systolic BP (OR 1.06, 95% CI 1.05, 1.08 per 10 mmHg increase), time to screening (OR for screening >1 year post diagnosis = 1.12, 95% CI 1.07, 1.17) and obesity (OR 0.87, 95% CI 0.82, 0.93) in multivariate analysis. CONCLUSIONS/INTERPRETATION: The prevalence of retinopathy at first screening is lower than in previous UK studies, consistent with earlier diagnosis of diabetes. Most newly diagnosed type 2 diabetic patients in Scotland are screened within an acceptable interval and the prevalence of referable disease is low, even in those with delayed screening.

Differences in efficacy and cytokine profiles following echinocandin or liposomal amphotericin B monotherapy or combination therapy for murine pulmonary or systemic Aspergillus flavus infections.

Given the recent increase in aspergillosis caused by species other than Aspergillus fumigatus, micafungin, caspofungin, and liposomal amphotericin B (L-AmBi) were investigated as monotherapy or combination therapy for murine systemic or pulmonary Aspergillus flavus infection. Treatment for 3 or 6 days was begun at 24 h (intravenous [i.v.], 2.8 × 10(4) conidia) or 2 h (intranasal, 4.1 × 10(6) to 6.75 × 10(6) conidia) postchallenge as follows: 5 or 10 mg/kg L-AmBi, 10 mg/kg caspofungin, 15 mg/kg micafungin, L-AmBi plus echinocandin, L-AmBi on days 1 to 3 and echinocandin on days 4 to 6, or echinocandin on days 1 to 3 and L-AmBi on days 4 to 6. Mice were monitored for survival, fungal burden, serum or tissue cytokines, and lung histopathology. In the systemic infection, micafungin or caspofungin was more effective than L-AmBi in prolonging survival (P < 0.05), and L-AmBi was associated with significantly elevated serum levels of interleukin-6 (IL-6), macrophage inflammatory protein 1α (MIP-1α), and IL-12 (P < 0.05). In contrast, L-AmBi was significantly more effective than the echinocandins in reducing fungal growth in most tissues (P < 0.05). Concomitant therapies produced significantly enhanced survival, reduction in fungal burden, and low levels of proinflammatory cytokines, while antagonism was seen with some sequential regimens. In comparison, in the pulmonary infection, L-AmBi was significantly better (P < 0.05) than caspofungin or the combination of L-AmBi and caspofungin in prolonging survival and reducing lung fungal burden. Caspofungin stimulated high lung levels of IL-1α, tumor necrosis factor alpha (TNF-α), and IL-6, with extensive tissue damage. In summary, systemic A flavus infection was treated effectively with L-AmBi plus micafungin or caspofungin provided that the drugs were administered concomitantly and not sequentially, while pulmonary A. flavus infection responded well to L-AmBi but not to caspofungin.

External quality assurance for image grading in the Scottish Diabetic Retinopathy Screening Programme.

AIMS: To develop and evaluate an image grading external quality assurance system for the Scottish Diabetic Retinopathy Screening Programme. METHOD: A web-based image grading system was developed which closely matches the current Scottish national screening software. Two rounds of external quality assurance were run in autumn 2008 and spring 2010, each time using the same 100 images. Graders were compared with a consensus standard derived from the top-level graders' results. After the first round, the centre lead clinicians and top-level graders reviewed the results and drew up guidance notes for the second round. RESULTS: Grader sensitivities ranged from 60.0 to 100% (median 92.5%) in 2008, and from 62.5 to 100% (median 92.5%) in 2010. Specificities ranged from 34.0 to 98.0% (median 86%) in 2008, and 54.0 to 100% (median 88%) in 2010. There was no difference in sensitivity between grader levels, but first-level graders had a significantly lower specificity than level-two and level-three graders. In 2008, one centre had a lower sensitivity but higher specificity than the majority of centres. Following the feedback from the first round, overall agreement improved in 2010 and there were no longer any significant differences between centres. CONCLUSIONS: A useful educational tool has been developed for image grading external quality assurance.

Bilateral retropharyngeal parathyroid hyperplasia detected with 4D multidetector row CT.

We present a case of bilateral retropharyngeal parathyroid hyperplasia detected with 4D-CT in a patient with persistent primary hyperparathyroidism and failed neck exploration. We discuss the embryologic basis of ectopic retropharyngeal parathyroid adenomas and hyperplasia and the utility of 4D-CT in their localization for surgical planning.

Differences in tissue drug concentrations following intravenous versus intraperitoneal treatment with amphotericin B deoxycholate or liposomal amphotericin B.

Amphotericin B formulations were compared in preclinical models by using intraperitoneal (ip) and intravenous (iv) delivery of amphotericin B deoxycholate (DAMB) or liposomal amphotericin B. We examined the effects on drug tissue penetration and retention resulting from different routes of drug administration. Mice were treated with equivalent total doses of AmBisome (AmBi) or DAMB (i.e.,15 mg/kg) given ip (3 mg/kg/day for 5 days) or iv (3 mg/kg/day AmBi for 5 days or 1 mg/kg/day DAMB for 15 days), with tissues collected 24 h post-treatment. For drug retention studies, mice were given iv or ip total doses of 30 mg/kg AmBi (10 mg/kg/day 3 x /week) or 60 mg/kg AmBi (20 mg/kg/day 3 x /week) with tissue collection 24 h or 7 days post-treatment. Blood samples were collected at 0.5 h, 2 h, 8 h, 12 h and 24 h after ip or iv drug dosing. A Paecilomyces variottii bioassay was used to determine drug concentrations. AmBi and DAMB were detected in the kidneys following iv, but not ip dosing. Significantly more DAMB than AmBi was detected in the lungs with ip dosing (P = 0.008), and more AmBi than DAMB (P = 0.056) was present with iv dosing. Unlike the lungs, the spleen and liver retained the AmBi for up to one week post-treatment regardless of the route of drug administration. Thus, there are significant differences in AmBi and DAMB tissue distribution depending upon the drug route and these differences could effect how the drugs perform in fungal infection models.

Costs and consequences of automated algorithms versus manual grading for the detection of referable diabetic retinopathy.

AIMS: To assess the cost-effectiveness of an improved automated grading algorithm for diabetic retinopathy against a previously described algorithm, and in comparison with manual grading. METHODS: Efficacy of the alternative algorithms was assessed using a reference graded set of images from three screening centres in Scotland (1253 cases with observable/referable retinopathy and 6333 individuals with mild or no retinopathy). Screening outcomes and grading and diagnosis costs were modelled for a cohort of 180 000 people, with prevalence of referable retinopathy at 4%. Algorithm (b), which combines image quality assessment with detection algorithms for microaneurysms (MA), blot haemorrhages and exudates, was compared with a simpler algorithm (a) (using image quality assessment and MA/dot haemorrhage (DH) detection), and the current practice of manual grading. RESULTS: Compared with algorithm (a), algorithm (b) would identify an additional 113 cases of referable retinopathy for an incremental cost of pound 68 per additional case. Compared with manual grading, automated grading would be expected to identify between 54 and 123 fewer referable cases, for a grading cost saving between pound 3834 and pound 1727 per case missed. Extrapolation modelling over a 20-year time horizon suggests manual grading would cost between pound 25,676 and pound 267,115 per additional quality adjusted life year gained. CONCLUSIONS: Algorithm (b) is more cost-effective than the algorithm based on quality assessment and MA/DH detection. With respect to the value of introducing automated detection systems into screening programmes, automated grading operates within the recommended national standards in Scotland and is likely to be considered a cost-effective alternative to manual disease/no disease grading.

Cost-effectiveness of implementing automated grading within the national screening programme for diabetic retinopathy in Scotland.

AIMS: National screening programmes for diabetic retinopathy using digital photography and multi-level manual grading systems are currently being implemented in the UK. Here, we assess the cost-effectiveness of replacing first level manual grading in the National Screening Programme in Scotland with an automated system developed to assess image quality and detect the presence of any retinopathy. METHODS: A decision tree model was developed and populated using sensitivity/specificity and cost data based on a study of 6722 patients in the Grampian region. Costs to the NHS, and the number of appropriate screening outcomes and true referable cases detected in 1 year were assessed. RESULTS: For the diabetic population of Scotland (approximately 160,000), with prevalence of referable retinopathy at 4% (6400 true cases), the automated strategy would be expected to identify 5560 cases (86.9%) and the manual strategy 5610 cases (87.7%). However, the automated system led to savings in grading and quality assurance costs to the NHS of 201,600 pounds per year. The additional cost per additional referable case detected (manual vs automated) totalled 4088 pounds and the additional cost per additional appropriate screening outcome (manual vs automated) was 1990 pounds. CONCLUSIONS: Given that automated grading is less costly and of similar effectiveness, it is likely to be considered a cost-effective alternative to manual grading.

The efficacy of automated "disease/no disease" grading for diabetic retinopathy in a systematic screening programme.

AIM: To assess the efficacy of automated "disease/no disease" grading for diabetic retinopathy within a systematic screening programme. METHODS: Anonymised images were obtained from consecutive patients attending a regional primary care based diabetic retinopathy screening programme. A training set of 1067 images was used to develop automated grading algorithms. The final software was tested using a separate set of 14 406 images from 6722 patients. The sensitivity and specificity of manual and automated systems operating as "disease/no disease" graders (detecting poor quality images and any diabetic retinopathy) were determined relative to a clinical reference standard. RESULTS: The reference standard classified 8.2% of the patients as having ungradeable images (technical failures) and 62.5% as having no retinopathy. Detection of technical failures or any retinopathy was achieved by manual grading with 86.5% sensitivity (95% confidence interval 85.1 to 87.8) and 95.3% specificity (94.6 to 95.9) and by automated grading with 90.5% sensitivity (89.3 to 91.6) and 67.4% specificity (66.0 to 68.8). Manual and automated grading detected 99.1% and 97.9%, respectively, of patients with referable or observable retinopathy/maculopathy. Manual and automated grading detected 95.7% and 99.8%, respectively, of technical failures. CONCLUSION: Automated "disease/no disease" grading of diabetic retinopathy could safely reduce the burden of grading in diabetic retinopathy screening programmes.

The prevalence of sight-threatening uveitis in Scotland.

AIM: To identify and quantify the prevalence of patients with uveitis receiving systemic immunosuppression in Scotland. METHODS: Anonymised data were prospectively collected on all patients with uveitis requiring systemic immunosuppression. Seven health boards participated over a 4-month period between 1 August 2005 and 30 November 2005. RESULTS: 373 patients were identified, of whom 205 (55%) were female. The mean age was 46.4 (range 7-97 years). Using the data from the seven participating health boards, an estimated Scottish prevalence of 9 per 100 000 was calculated. Prevalence varied between 2 and 59 per 100 000. In National Health Service Grampian, all patients with uveitis, whether sight-threatening or not, are followed up at a specialist clinic. Extrapolating this figure to Scotland gives a prevalence of 25 per 100 000. DISCUSSION: The data from National Health Service Grampian suggest that there is a significant shortfall in the number of patients identified by survey. If the "missing population" exists, then where are they? Some might be receiving appropriate treatment at non-specialist clinics, although simple under-reporting may play a part. Greater concern is for those patients receiving inappropriate treatment for their uveitis, or for those within the community who are either oblivious to or in self denial of their condition.

Elevated plasma CD105 and vitreous VEGF levels in diabetic retinopathy.

Diabetic retinopathy is the leading cause of blindness in the industrialized world. Hyperglycaemia induces retinal hypoxia that upregulates a range of vasoactive factors which may lead to macular oedema and/or angiogenesis and hence potentially sight threatening retinopathy. In this study, we have focused on the association of CD105 and vascular endothelial growth factor (VEGF) with the development and progression of diabetic retinopathy by means of quantifying their expression in the plasma and vitreous of diabetic patients. CD105 levels were quantified in the plasma of 38 type I diabetic patients at various stages of retinopathy and 15 non-diabetic controls. In an additional cohort of 11 patients with advanced proliferative retinopathy and 23 control subjects, CD105 and VEGF were measured in the vitreous. The values were expressed as median (range) and statistical analysis was carried out using the non-parametric Mann-Whitney U test. Plasma CD105 levels were significantly increased in diabetic patients [1.8 (1.1-2.4) ng/ml] compared with non-diabetic controls [0.7 (0.3-1.8) ng/ml] (p<0.01). Plasma CD105 levels were elevated in diabetic patients with all stages of retinopathy, the highest level was observed in background retinopathy [2.3 (2.1-2.5) ng/ml] followed by proliferative retinopathy [2.1 (0.9-2.8) ng/ml] and advanced proliferative retinopathy [1.4 (0.6-1.8) ng/ml]. Vitreous contents of CD105 did not differ between controls and patients with advanced proliferative retinopathy, but vitreous levels of VEGF were elevated by approximately 3-fold in patients with advanced proliferative retinopathy [7.2 (1.90-15.60) ng/ml] compared with the control subjects [1.80 (1.10-2.210)] (p<0.01). These observations indicate that plasma levels of CD105 and vitreous levels of VEGF are associated with diabetic retinopathy, suggesting that CD105 and the angiogenic factor VEGF may play a critical role in the development and progression of diabetic retinopathy. Further studies are required to determine whether circulating CD105 levels could serve as a surrogate marker for early stage retinopathy and for monitoring disease progression.