Absence of Anemia in Maintenance Hemodialysis

Anemia is usual in untreated uremia. Persistent anemia is thought to be universal in uremic patients treated by maintenance hemodialysis (MH). A retrospective chart analysis of 549 patients on (MH) at five facilities in Brooklyn, found that eleven (2%) of these patients had a hematocrit (Hct) in the normal range (40%). To distinguish this subset of patients from the majority of MH, we compared both groups for: (1) etiology of the renal disease, (2) presence of residual renal function, (3) dialysis prescription, (4) decreased arterial O2 saturation, (5) greater use of vitamins or anabolic steroids, (6) absence of parathyroid disease. The relatively high hematocrit was not explained by any factor evaluated in this small subset of MH patients.

Modelling the variation in skin-test tuberculin reactions, post-mortem lesion counts and case pathology in tuberculosis-exposed cattle: Effects of animal characteristics, histories and co-infection

Correctly identifying bovine tuberculosis (bTB) in cattle remains a significant problem in endemic countries. We hypothesized that animal characteristics (sex, age, breed), histories (herd effects, testing, movement) and potential exposure to other pathogens (co-infection; BVDV, liver fluke and Mycobacterium avium reactors) could significantly impact the immune responsiveness detected at skin testing and the variation in post-mortem pathology (confirmation) in bTB-exposed cattle. Three model suites were developed using a retrospective observational data set of 5,698 cattle culled during herd breakdowns in Northern Ireland. A linear regression model suggested that antemortem tuberculin reaction size (difference in purified protein derivative avium [PPDa] and bovine [PPDb] reactions) was significantly positively associated with post-mortem maximum lesion size and the number of lesions found. This indicated that reaction size could be considered a predictor of both the extent (number of lesions/tissues) and the pathological progression of infection (maximum lesion size). Tuberculin reaction size was related to age class, and younger animals (<2.85 years) displayed larger reaction sizes than older animals. Tuberculin reaction size was also associated with breed and animal movement and increased with the time between the penultimate and disclosing tests. A negative binomial random-effects model indicated a significant increase in lesion counts for animals with M. avium reactions (PPDb-PPDa < 0) relative to non-reactors (PPDb-PPDa = 0). Lesion counts were significantly increased in animals with previous positive severe interpretation skin-test results. Animals with increased movement histories, young animals and non-dairy breed animals also had significantly increased lesion counts. Animals from herds that had BVDV-positive cattle had significantly lower lesion counts than animals from herds without evidence of BVDV infection. Restricting the data set to only animals with a bTB visible lesion at slaughter (n = 2471), an ordinal regression model indicated that liver fluke-infected animals disclosed smaller lesions, relative to liver fluke-negative animals, and larger lesions were disclosed in animals with increased movement histories.

A comparison of outcomes following tibial plateau levelling osteotomy and cranial tibial wedge osteotomy procedures

The objective of this study was to determine whether clinical outcomes were superior and complication rates were lower in dogs that had had a cranial cruciate ligament rupture treated by tibial plateau levelling osteotomy (TPLO), compared to those dogs that had been treated using the original cranial tibial wedge osteotomy (CTWO) procedure. Thirty-seven client-owned dogs with cranial cruciate ligament rupture were included in the study: 19 dogs underwent a TPLO procedure, and 18 dogs underwent a CTWO procedure. The study was retrospective, with the data being obtained from medical records and a review of radiographs. The long-term outcome was assessed by means of an owner questionnaire using a visual analogue scale. For the majority of factors that were reviewed, there was not a significant difference in outcome between the dogs that had a TPLO or those that had undergone a CTWO. All of the dogs showed a rapid return to weight bearing after surgery, and at the six week re-examination, the majority of the dogs did not have any pain on stifle palpation. They displayed a good stifle range of motion and significantly lower lameness scores than those prior to surgery. The complication rates did not differ between the procedures, however, within this small sample of dogs, complications following a CTWO were more likely to require revision surgery.

Whole body physiologically based modelling of β-blockers in the rat: events in tissues and plasma following an i.v. bolus dose

BACKGROUND AND PURPOSE

Whole body physiologically based pharmacokinetic (PBPK) models have been increasingly applied in drug development to describe kinetic events of therapeutic agents in animals and humans. The advantage of such modelling is the ability to incorporate vast amounts of physiological information, such as organ blood flow and volume, to ensure that the model is as close to reality as possible.

EXPERIMENTAL APPROACH

Previous PBPK model development of enantiomers of a series of seven racemic β-blockers, namely, acebutolol, betaxolol, bisoprolol, metoprolol, oxprenolol, pindolol and propranolol, together with S-timolol in rat was based on tissue and blood concentration data at steady state. Compounds were administered in several cassettes with the composition mix and blood and tissue sampling times determined using a D-optimal design.

KEY RESULTS

Closed-loop PBPK models were developed initially based on the application of open loop forcing function models to individual tissues and compounds. For the majority of compounds and tissues, distribution kinetics was adequately characterized by perfusion rate-limited models. For some compounds in the testes and gut, a permeability rate-limited distribution model was required to best fit the data. Parameter estimates of the tissue-to-blood partition coefficient through fitting of individual enantiomers and of racemic pair were generally in agreement and also concur with those from previous steady-state experiments.

CONCLUSIONS AND IMPLICATIONS

PBPK modelling is a very powerful tool to aid drug discovery and development of therapeutic agents in animals and humans. However, careful consideration of the assumptions made during the modelling exercise is essential.

Effectiveness of Internet-based interventions in managing chemotherapy-related symptoms in patients with cancer: a systematic literature review

PURPOSE

The aims of this review were to (1) examine the effectiveness of Internet-based interventions on cancer chemotherapy-related physical symptoms (severity and/or distress) and health-related quality of life (HRQOL) outcomes and (2) identify the design elements and processes for implementing these interventions in oncology practices.

METHODS

A systematic review was performed. The Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, CINAHL, and PsycINFO were searched for studies dating from January 2000 through to October 2016. Based on pre-determined selection criteria, data was extracted from eligible studies. Methodological quality of studies was assessed using an adapted version of the Cochrane Collaboration Back Review Group checklist.

RESULTS

The literature search yielded 1766 studies of which only six RCTs fulfilled the eligibility criteria. Although the content, duration, and frequency of interventions varied considerably across studies, commonly used elements included tailored information, education, self-management support, and communication with clinicians. Five studies measured symptom distress and four of them reported statistically significant differences between study groups. Of the three studies that measured HRQOL, two reported improvement (or no deterioration over time) for the intervention group. However, several methodological issues including high attrition rates, poor adherence to interventions, and use of non-validated measures affect confidence in the strength of evidence.

CONCLUSION

Despite the evidence in support of using the Internet as a worthwhile tool for effective patient engagement and self-management of chemotherapy-related symptoms outside clinic visits, methodological limitations in the evidence base require further well-planned and quality research.

Abnormal von Willebrand factor secretion, factor VIII stabilization and thrombus dynamics in type 2N von Willebrand disease mice

Essentials Type 2N von Willebrand disease involves impaired von Willebrand factor to factor VIII binding. Type 2N von Willebrand disease mutations exhibit qualitative and mild quantitative deficiencies. Type 2N von Willebrand disease mice exhibit unstable venous hemostatic thrombi. The factor VIII-binding ability of von Willebrand factor regulates arteriole thrombosis dynamics.

SUMMARY

Background von Willebrand factor (VWF) and factor VIII (FVIII) circulate as a non-covalent complex, with VWF serving as the carrier for FVIII. VWF indirectly influences secondary hemostasis by stabilizing FVIII and transporting it to the site of primary hemostasis. Type 2N von Willebrand disease involves impaired binding of VWF to FVIII, resulting in decreased plasma levels of FVIII. Objectives In these studies, we characterize the impact of three type 2N VWD variants (R763A, R854Q, R816W) on VWF secretion, FVIII stabilization and thrombus formation in a murine model. Methods Type 2N VWD mice were generated by hydrodynamic injections of mutant murine VWF cDNAs and the influence of these variants on VWF secretion and FVIII binding was evaluated. In vivo hemostasis and the dynamics of thrombus formation and embolization were assessed using a murine tail vein transection hemostasis model and an intravital thrombosis model in the cremaster arterioles. Results Type 2N VWD variants were associated with decreased VWF secretion using cell and animal-based models. FVIII-binding to type 2N variants was impaired in vitro and was variably stabilized in vivo by expressed or infused 2N variant VWF protein. Both transgenic type 2N VWD and FVIII knockout (KO) mice demonstrated impaired thrombus formation associated with decreased thrombus stability. Conclusions The type 2N VWD phenotype can be recapitulated in a murine model and is associated with both quantitative and qualitative VWF deficiencies and impaired thrombus formation. Patients with type 2N VWD may have normal primary hemostasis formation but decreased thrombus stability related to ineffective secondary hemostasis.

Operative learning curve trajectory in a cohort of surgical trainees

Background

Certification of completion of training in general surgery in the UK requires demonstration of competence in index operations by means of three level 4 competence consultant-validated procedure-based assessments (PBAs). The aim of this study was to evaluate the trajectory of operative learning curves related to PBA performance levels for curriculum-defined indicative operations with respect to numbers performed and training time.

Methods

Logbook data from consecutive higher general surgical trainees were compared with PBA evaluations to determine the relationship between PBA performance level, operative experience, training time and indicative numbers. Learning curve gradients were calculated using the inverse trigonometric function of tan related to operative experience and training time.

Results

Eighty-four surgical trainees participated. Median caseload to achieve three level 4 competence assessments was 64 (range 18–110) for inguinal hernia, 83 (15–177) for emergency laparotomy, 87 (23–192) for laparoscopic cholecystectomy, 95 (22–209) for appendicectomy, 45 (17–111) for segmental colectomy and 16 (6–28) for Hartmann's procedure. Median learning curve gradients to achieve level 4 competence for emergency laparotomy were 15·3° and 33·7° by caseload and training time respectively, compared with 73·3° and 59·9° for Hartmann's procedure. Significant variance was observed in the gradients of all learning curves related to both the caseload between the first level 3 and the first level 4 PBA (P = 0·001), and between the first and third level 4 PBAs (P &lt; 0·001).

Conclusion

Significant learning curve gradient variance was observed, with discrepancies between expected indicative operative numbers and the point at which competence was judged to have been achieved. Numbers of index operations to achieve certification of completion of training warrant further examination.

Comorbidity, age of onset and suicidality in obsessive-compulsive disorder (OCD): An international collaboration

OBJECTIVES

To collate data from multiple obsessive-compulsive disorder (OCD) treatment centers across seven countries and five continents, and to report findings in relation to OCD comorbidity, age of onset of OCD and comorbid disorders, and suicidality, in a large clinical and ethnically diverse sample, with the aim of investigating cultural variation and the utility of the psychiatric diagnostic classification of obsessive-compulsive and related disorders.

METHODS

Researchers in the field of OCD were invited to contribute summary statistics on current and lifetime psychiatric comorbidity, age of onset of OCD and comorbid disorders and suicidality in their patients with OCD.

RESULTS

Data from 3711 adult patients with primary OCD came from Brazil (n=955), India (n=802), Italy (n=750), South Africa (n=565), Japan (n=322), Australia (n=219), and Spain (n=98). The most common current comorbid disorders were major depressive disorder (28.4%; n=1055), obsessive-compulsive personality disorder (24.5%, n=478), generalized anxiety disorder (19.3%, n=716), specific phobia (19.2%, n=714) and social phobia (18.5%, n=686). Major depression was also the most commonly co-occurring lifetime diagnosis, with a rate of 50.5% (n=1874). OCD generally had an age of onset in late adolescence (mean=17.9years, SD=1.9). Social phobia, specific phobia and body dysmorphic disorder also had an early age of onset. Co-occurring major depressive disorder, generalized anxiety disorder and psychotic disorders tended to have a later age of onset than OCD. Suicidal ideation within the last month was reported by 6.4% (n=200) of patients with OCD and 9.0% (n=314) reported a lifetime history of suicide attempt.

CONCLUSIONS

In this large cross-continental study, comorbidity in OCD was common. The high rates of comorbid major depression and anxiety disorders emphasize the need for clinicians to assess and monitor for these disorders. Earlier ages of onset of OCD, specific phobia and social phobia may indicate some relatedness between these disorders, but this requires further study. Although there do not appear to be significant cultural variations in rates or patterns of comorbidity and suicidality, further research using similar recruitment strategies and controlling for demographic and clinical variables may help to determine whether any sociocultural factors protect against suicidal ideation or psychiatric comorbidity in patients with OCD.

Finite element analysis to investigate variability of MR elastography in the human thigh

PURPOSE

To develop finite element analysis (FEA) of magnetic resonance elastography (MRE) in the human thigh and investigate inter-individual variability of measurement of muscle mechanical properties.

METHODS

Segmentation was performed on MRI datasets of the human thigh from 5 individuals and FEA models consisting of 12 muscles and surrounding tissue created. The same material properties were applied to each tissue type and a previously developed transient FEA method of simulating MRE using Abaqus was performed at 4 frequencies. Synthetic noise was applied to the simulated data at various levels before inversion was performed using the Elastography Software Pipeline. Maps of material properties were created and visually assessed to determine key features. The coefficient of variation (CoV) was used to assess the variability of measurements in each individual muscle and in the groups of muscles across the subjects. Mean measurements for the set of muscles were ranked in size order and compared with the expected ranking.

RESULTS

At noise levels of 2% the CoV in measurements of |G^*| ranged from 5.3 to 21.9% and from 7.1 to 36.1% for measurements of ϕ in the individual muscles. A positive correlation (R² value 0.80) was attained when the expected and measured |G^*| ranking were compared, whilst a negative correlation (R² value 0.43) was found for ϕ.

CONCLUSIONS

Created elastograms demonstrated good definition of muscle structure and were robust to noise. Variability of measurements across the 5 subjects was dramatically lower for |G^*| than it was for ϕ. This large variability in ϕ measurements was attributed to artefacts.

Hierarchical Logic Models as a Tool to Evaluate Programmatic Initiatives: Practical Solutions to Identified Problems

INTRODUCTION

Large programmatic grants advance the missions of funding agencies or organizations. This article describes the programmatic impact of using "hierarchical" logic models in two Centers funded by the National Institute of Occupational Safety and Health (NIOSH) that were designed to achieve NIOSH goals. Such models are supportive of priority setting, policy implementation, and effective evaluation.

METHODS

Two NIOSH Centers, an Agricultural Center and an Occupational Safety and Health Education and Research Center, used the same hierarchical logic model process to support the NIOSH programmatic goal of improving worker health and safety in their respective occupational categories. The logic model development processes were led by the same evaluator.

RESULTS

Case studies describe the utilization of "hierarchical" logic models: in each case, NIOSH was the "grandparent", the Center was its descendant (parent) and the cores were the children. This lineage was articulated through the Center-wide logic model and through the logic model of each of its core programmatic areas (core). The Center-wide logic model ensured that the Center's goals, and the intended outcomes and impact of its work were linked to the mission and goals of NIOSH. Each core's logic model articulated how its goals, activities, and outcomes were specifically linked to the Center-wide model.

DISCUSSION

A hierarchical logic model process ensures that the objectives of the funding agency or organization are addressed, and enables stakeholders to articulate the linkages between each layer. This facilitates the process of developing, implementing and evaluating programmatic elements within the framework of strategic planning.

Smoking at diagnosis significantly decreases 5-year cancer-specific survival in a population-based cohort of 18 166 colon cancer patients

BACKGROUND

Accumulating evidence suggests smoking may adversely affect cancer patients' outcomes. Previous studies of smoking and survival in colon cancer have been limited by size and/or lack of a population basis and results have been inconsistent.

AIM

To investigate in a large population-based cohort whether smoking status at diagnosis is an independent prognostic factor for cancer-specific survival in colon cancer and whether treatment modifies any impact of smoking.

METHODS

Colon adenocarcinomas diagnosed between 1994 and 2012 were abstracted from the National Cancer Registry Ireland, and classified by smoking status at diagnosis. Cancer-specific death rates over 5 years were compared in current, ex- and never smokers using multivariable Cox proportional hazards models, and subgroup analyses by treatment (combinations of cancer-directed surgery and chemotherapy) were conducted.

RESULTS

Of 18 166 colon cancers, 20% of patients were current smokers, 23% ex-smokers and 57% never smokers. Compared to never smokers, current smokers had a significantly raised cancer death rate [multivariable hazard ratio (HR) = 1.14, 95% CI: 1.07-1.12]. There was a significant interaction between treatment and smoking (P = 0.03). In those who had cancer-directed surgery only, but not other groups, current smokers had a significantly increased cancer death rate compared to never smokers (HR = 1.21, 95% CI: 1.09-1.34).

CONCLUSIONS

Smoking at diagnosis is an independent prognostic factor for colon cancer. The limitation of the association to surgically-treated patients suggests that the underlying mechanism(s) may be related to surgery. While further research is needed to elucidate mechanisms, continued efforts to encourage smoking prevention and cessation may yield benefits in terms of improved survival from colon cancer.