Modeling Pressure Drop Using Generalized Scaffold Characteristics in an Axial-Flow Bioreactor for Soft Tissue Regeneration

The goal of this study was to better understand how analytical permeability models based on scaffold architecture can facilitate a non-invasive technique to real time monitoring of pressure drop in bioreactors. In particular, we evaluated the permeability equations for electrospun and freeze dried scaffolds via pressure drop comparison in an axial-flow bioreactor using computational fluid dynamic (CFD) and experimentation. The polycaprolactone–cellulose acetate fibers obtained by co-axial electrospinning technique and Chitosan–Gelatin scaffolds prepared using freeze-drying techniques were utilized. Initially, the structural properties (fiber size, pore size and porosity) and mechanical properties (elastic modulus and Poisson’s ratio) of scaffolds in phosphate buffered saline at 37 °C were evaluated. The CFD simulations were performed by coupling fluid flow, described by Brinkman equation, with structural mechanics using a moving mesh. The experimentally obtained pressure drop values for both 1 mm thick and 2 mm thick scaffolds agreed with simulation results. To evaluate the effect of permeability and elastic modulus on pressure drop, CFD predictions were extended to a broad range of permeabilities spanning synthetic scaffolds and tissues, elastic moduli, and Poisson’s ratio. Results indicated an increase in pressure drop with increase in permeability. Scaffolds with higher elastic modulus performed better and the effect of Poisson’s ratio was insignificant. Flow induced deformation was negligible in axial-flow bioreactor. In summary, scaffold permeabilities can be calculated using scaffold microarchitecture and can be used in non-invasive monitoring of tissue regeneration.     

Teleophthalmology in Diabetic Retinopathy

Over the past decade, there have been rapid strides in progress in the fields of telecommunication and medical imaging. There is growing evidence regarding use of teleophthalmology for screening of diabetic retinopathy. This article highlights some pertinent questions regarding use of telescreening for diabetic retinopathy. It deals with evidence regarding accuracy of diagnosis, patients satisfaction and cost-effectiveness. The American Telemedicine Association have given certain guidelines for teleheath practices for diabetic retinopathy. The article discusses regarding these guidelines. Finally, a working model for diabetic retinopathy screening through teleophthalmology has been described. Telescreening for diabetic retinopathy seems to be a cost-effective, accurate, and reliable method for screening for diabetic retinopathy. The American Telemedicine Association has set up guidelines for telescreening that should be adhered to provide quality screening services to people with diabetes.     

Cardiovascular and hormonal responses to a meal in hypertrophic cardiomyopathy: A comparison of patients with and without postprandial exacerbation of symptoms

Some patients with hypertrophic cardiomyopathy experience postprandial exacerbation of symptoms. The aim of this study was to determine whether the hemodynamic and/or hormonal responses to a meal differ between patients with and without postprandial symptoms. Ten hypertrophic cardiomyopathy patients with postprandial symptoms, 10 patients without postprandial symptoms, and 10 normal subjects ate a 740 Kcal meal, following which heart rate, blood pressure, and echocardiographic and gastrointestinal hormone changes were compared among the three groups. Heart rate increased (p<0.001) and diastolic blood pressure fell (p < 0.001) to a similar degree in the three groups. Left ventricular outflow tract velocity increased (p< 0.01) and some patients had substantial increases in outflow tract pressure gradient; however, this was independent of the presence or absence of postprandial symptoms. The atrial contribution to filling increased in normal subjects and in both groups of hypertrophic cardiomyopathy patients. There was no significant difference in the gastrointestinal hormone changes in the three groups. In summary, there is no evidence for a distinctive hemodynamic or hormonal response to food in hypertrophic cardiomyopathy patients with postprandial symptoms. These symptoms more likely reflect differences in underlying cardiac disease characteristics and severity.     

Ethnic and cultural determinants influence risk assessment for hepatitis C acquisition

BACKGROUND AND AIM: In the developed world hepatitis C virus (HCV) infection is predominantly associated with sharing contaminated equipment between injecting drug users (IDU). In developing countries inadequately sterilized medical equipment, transmission of infected blood and cultural practices have been implicated. Accurate risk factor assessment is essential for education targeted at risk reduction in culturally diverse populations. METHODS: Ninety Australian-born Caucasians and 72 South-east Asian (SEA) HCV patients attending a Melbourne hospital liver clinic completed a questionnaire which assessed risk factor profile, perceived risk factors, knowledge of risk factors and methods to minimize transmission. Medical records were audited to identify doctor assessment of risk factors. RESULTS: Risk factors in Caucasians were IDU, body piercing and tattooing (89%, 47% and 32%, respectively). Risk factors in SEA patients were injection therapy, dental therapy and surgery (89%, 70% and 38%, respectively). Most Caucasian patients (94%) correctly identified their mode of acquisition compared with 33% of SEA patients (P < 0.0001). Accurate risk factor documentation in medical records was more common in Caucasians (96 vs 32%; P < 0.0001). The majority of patients identified blood-to-blood and sexual/vertical transmission as important modes of acquisition. However, 33% of SEA patients believed transmission occurred through food, water and poor hygiene and 80% did not identify therapeutic injection or traditional medical practices as risk factors. Education provided to SEA patients did not address less well established routes of transmission. CONCLUSIONS: Ethnicity influences perception and knowledge of risk factors. Improved assessment of risk factors in high-risk ethnic groups is needed. Education should be culturally appropriate and address the concerns of all populations with HCV.     

Heart failure education in the emergency department markedly reduces readmissions in un- and under-insured patients

Background

Heart failure (HF) readmissions are a longstanding national healthcare issue for both hospitals and patients. Our purpose was to evaluate the efficacy of a structured, educational intervention targeted towards un- and under-insured emergency department (ED) HF patients.

Management of Dyslipidemia in Patients with Hypertension,Diabetes, and Metabolic Syndrome

Purpose of Review

The purpose of this review is to discuss dyslipidemia in the various common clinical conditions including hypertension, diabetes mellitus, and metabolic syndrome and review the current therapeutic strategy in these settings.

Recent Findings

Dyslipidemias are common in patients with hypertension, diabetes mellitus, and metabolic syndrome. Epidemiologic studies have shown a strong correlation between serum lipid levels and risk of atherosclerotic cardiovascular disease. Multifactorial intervention strategies aimed at controlling lipids, blood pressure, and blood glucose simultaneously achieve maximal reductions in cardiovascular risk.

Summary

Dyslipidemia and metabolic abnormalities are strongly associated with atherosclerosis and worse cardiovascular outcomes. While pharmacotherapy with statins has been proven to be beneficial for dyslipidemia, lifestyle modification emphasizing weight loss and regular exercise is an essential component of the interventional strategy. The common thread underlying atherosclerosis and metabolic abnormalities is endothelial dysfunction. Improved understanding of the role of endothelium in health and disease can potentially lead to novel therapies that may preempt development of atherosclerosis and its complications.

     

Readmission patterns in patients with chronic obstructive pulmonary disease, chronic heart failure and diabetes mellitus: an administrative dataset analysis

Comprehensive disease management programmes for chronic disease aim to improve patient outcomes and reduce health-care utilization. Readmission rates are often used as an outcome measure of effectiveness. This study aimed to document readmission rates, and risk for early and late readmission, for patients discharged from the Royal Melbourne Hospital with a disease diagnosis of chronic heart failure (CHF), chronic obstructive pulmonary disease (COPD) or diabetes mellitus compared to those with other general medical conditions. Eighty five (8.6%) of patients were readmitted within 28 days and 183 (20.8%) were readmitted between 29 and 180 days. No risk factors for early readmission were identified. Patients with a primary disease diagnosis of CHF and COPD are at increased risk of late readmissions (29-180 days).     

Palliative and supportive care needs of patients with high-grade glioma and their carers: A systematic review of qualitative literature

Objective

Patients diagnosed with Primary Malignant Glioma (PMG) face substantial challenges with poor prognosis, high symptom burden and care needs. This study aims to collate current literature detailing the supportive and palliative care needs of patients with PMG and their carers, and to subject it to a novel approach of formal evaluation.

Methods

Medline, EMBASE, CINAHL, PsychInfo were searched with core concepts: (1) glioma, (2) high-grade disease, and (3) palliative and supportive care needs. A narrative synthesis approach was undertaken including a quality appraisal of the 21 included studies.

Results

Key themes related to the need for consistent well-delivered information around disease sequelae, treatment, and resources available; health service needs including a key professional identified to coordinate care; the need for psychological and social supports, and clear avenues of communication with treating professionals.

Conclusion

The literature remains limited in the number and quality of evidence with two Level I, eight Level II, and eleven Level III studies. The findings call for improved information, communication and support practices to address the complexity and breadth of needs.

Practice implications

Specialised and individually tailored information, attention to clear, consistent communication and support practices should be incorporated into a future needs-based model of care.     

Venous sinus stenting for the treatment of isolated pulsatile tinnitus: Results of a prospective trial

ObjectivesThis prospective study evaluates the effectiveness and safety of venous sinus stenting for patients with isolated pulsatile tinnitus and lateral sinus stenosis.MethodsPatients with isolated pulsatile tinnitus and lateral sinus stenosis with a minimum trans stenotic gradient of 4 mm Hg were treated with stenting. Pulsatile tinnitus before and after treatment was assessed with the Tinnitus Handicap Inventory (THI). Periprocedural adverse events, neurological complications, clinical and radiographic follow-up were also recorded.ResultsA total of 42 patients (41 females and 1 male) were included in the study (median age of 37.5 years). Thirty patients had post-stenotic fusiform and 12 had post-stenotic saccular venous sinus aneurysm. In addition to stenting, coils were used to treat the patients with saccular venous aneurysms. The median follow-up was 5 months (range 1 to 34 months). Most patients had complete (39/42) or near-complete (2/42) resolution of their pulsatile tinnitus post-procedure. There were no serious adverse events.ConclusionStenting of the lateral venous sinus is a safe and effective treatment for patients with isolated pulsatile tinnitus due to venous sinus stenosis.