A combined numerical and experimental framework for determining permeability properties of the arterial media

The medial layer of the arterial wall may play an important role in the regulation of water and solute transport across the wall. In particular, a high medial resistance to transport could cause accumulation of lipid-carrying molecules in the inner wall. In this study, the water transport properties of medial tissue were characterised in a numerical model, utilising experimentally obtained data for the medial microstructure and the relative permeability of different constituents. For the model, a new solver for flow in porous materials, based on a high-order splitting scheme, was implemented in the spectral/hp element library nektar++ and validated. The data were obtained by immersing excised aortic bifurcations in a solution of fluorescent protein tracer and subsequently imaging them with a confocal microscope. Cuboidal regions of interest were selected in which the microstructure and relative permeability of different structures were transformed to a computational mesh. Impermeable objects were treated fictitiously in the numerical scheme. On this cube, a pressure drop was applied in the three coordinate directions and the principal components of the permeability tensor were determined. The reconstructed images demonstrated the arrangement of elastic lamellae and interspersed smooth muscle cells in rat aortic media; the distribution and alignment of the smooth muscle cells varied spatially within the extracellular matrix. The numerical simulations highlighted that the heterogeneity of the medial structure is important in determining local water transport properties of the tissue, resulting in regional and directional variation of the permeability tensor. A major factor in this variation is the alignment and density of smooth muscle cells in the media, particularly adjacent to the adventitial layer.

A Census of X-ray gas in NGC 1068: Results from 450ks of Chandra HETG Observations

We present models for the X-ray spectrum of the Seyfert 2 galaxy NGC 1068. These are fitted to data obtained using the High Energy Transmission Grating (HETG) on the Chandra X-ray observatory. The data show line and radiative recombination continuum (RRC) emission from a broad range of ions and elements. The models explore the importance of excitation processes for these lines including photoionization followed by recombination, radiative excitation by absorption of continuum radiation and inner shell fluorescence. The models show that the relative importance of these processes depends on the conditions in the emitting gas, and that no single emitting component can fit the entire spectrum. In particular, the relative importance of radiative excitation and photoionization/recombination differs according to the element and ion stage emitting the line. This in turn implies a diversity of values for the ionization parameter of the various components of gas responsible for the emission, ranging from log(ξ)=1 - 3. Using this, we obtain an estimate for the total amount of gas responsible for the observed emission. The mass flux through the region included in the HETG extraction region is approximately 0.3 M_⊙ yr^-1 assuming ordered flow at the speed characterizing the line widths. This can be compared with what is known about this object from other techniques.

The relationship between ambient ultraviolet radiation (UVR) and objectively measured personal UVR exposure dose is modified by season and latitude

Despite the widespread use of ambient ultraviolet radiation (UVR) as a proxy measure of personal exposure to UVR, the relationship between the two is not well-defined.

Use of the Accordion Severity Grading System for negative outcomes of carpal tunnel syndrome

A universal classification of the negative outcomes of carpal tunnel release surgery does not, as yet, exist. In order to avoid the use of arbitrary factors we have applied the Accordion Severity Grading System, which uses rigorously defined qualitative terms to classify complications. It also provides a uniform manner for grading the severity of complications, enabling outcome comparisons between centres. We analysed the negative outcomes of 500 device-assisted carpal tunnel releases performed over a 2-year period in the author's department. In order to establish a standardised list of complications we used the terms employed within the guidelines of the American Academy of Orthopaedic Surgeons. Most of these terms were subsequently defined using the data variables and definitions taken from the American College of Surgeons National Surgical Quality Improvement Program or the Medical Subject Headings of the National Library of Medicine. We also adopted the quantitative severity weighting, as proposed by the Accordion system, in order to determine the postoperative morbidity index for our assisted carpal tunnel releases. The most common complications were pain and reversible damage to peripheral nerves. Other common negative events, other than complications, included hand weakness, which we classified as a sequela of the procedure, and incomplete retinaculum release, which we classified as failure to cure. The overall postoperative morbidity index for complications was 0.014. Although the Accordion system was developed for more complex procedures, it may also be adopted for carpal tunnel release surgery where it provides an objective and universal method for the classification of complications.

The AusD Study: a population-based study of the determinants of serum 25-hydroxyvitamin D concentration across a broad latitude range

Observational studies suggest that people with a high serum 25-hydroxyvitamin D (25(OH)D) concentration may have reduced risk of chronic diseases such as osteoporosis, multiple sclerosis, type 1 diabetes, cardiovascular disease, and some cancers. The AusD Study (A Quantitative Assessment of Solar UV Exposure for Vitamin D Synthesis in Australian Adults) was conducted to clarify the relationships between ultraviolet (UV) radiation exposure, dietary intake of vitamin D, and serum 25(OH)D concentration among Australian adults residing in Townsville (19.3°S), Brisbane (27.5°S), Canberra (35.3°S), and Hobart (42.8°S). Participants aged 18-75 years were recruited from the Australian Electoral Roll between 2009 and 2010. Measurements were made of height, weight, waist:hip ratio, skin, hair, and eye color, blood pressure, and grip strength. Participants completed a questionnaire on sun exposure and vitamin D intake, together with 10 days of personal UV dosimetry and an associated sun-exposure and physical-activity diary that was temporally linked to a blood test for measurement of 25(OH)D concentration. Ambient solar UV radiation was also monitored at all study sites. We collected comprehensive, high-quality data from 1,002 participants (459 males, 543 females) assessed simultaneously across a range of latitudes and through all seasons. Here we describe the scientific and methodological issues considered in designing the AusD Study.

Experimental methods of abdominal aortic aneurysm creation in swine as a large animal model

Animal models of abdominal aortic aneurysms (AAA) enable preclinical studies on new therapeutic approaches and help to understand pathophysiology of the disease. The aim of this study was to demonstrate the effectiveness of selected methods of experimental induction of abdominal aortic aneurysm in swine and to adapt the EMG examination (electromyography) to record the vessel wall changes. The animals were divided into 3 groups comprising 4 individuals in whom AAA was surgically induced. In the first group the AAA was induced by mechanical stretching of the aortic wall and injection of 500 IU elastase under pressure. The second group received elastase and 6000 IU of collagenase. In the third group 0.5 M CaCl2 solution was introduced additionally. Enlargement of abdominal aorta was monitored for 4 weeks. The first group did not show any aorta dilatation. In the second group the aortic lumen was dilated on average by 71±3.5% (P≤0.001) as shown at autopsy and by 76.6±9.3% as measured by the ultrasound method. In the third group aorta was dilatated by 104.2±11.3% as obtained by ultrasound and 72±3% at post-mortem examination. Myoelectric activity of VSMC (vascular smooth muscle cell) was demonstrated and it was characterized by the presence of three types of waves closely related to the pressure changes in the vessel lumen. We conclude that collagen fibers damage plays a significant role in the AAA development in swine. The inflammatory process in the vessel's wall also contributes to AAA development. However, myoelectrical activity of VSMC does not significantly change despite histologically confirmed loss of muscular layer.

[Periprosthetic femoral bone reaction after total hip arthroplasty with preservation of the collum femoris : CT-assisted osteodensitometry 1 and 3 years postoperatively]

BACKGROUND

Short-stemmed cementless femoral components in total hip arthroplasty have been designed to preserve the proximal femoral bone stock by load transfer to the femoral metaphysis. An in vivo method of computed tomography-assisted (CT) osteodensitometry after total hip arthroplasty is presented which differentiates between cortical and cancellous bone density (BD) changes around uncemented femoral components.

PATIENTS AND METHODS

Cortical and cancellous periprosthetic femoral BD (mg Ca HA/ml) was determined prospectively in 31 patients at day 10, 1 year and 3 years after total hip arthroplasty with preservation of the collum femoris (C.F.P.-stem, Link, Hamburg, Germany) using computed tomography-assisted osteodensitometry. Clinical results (Harris hip score) and plain x-rays were assessed in all cases.

RESULTS

Progressive proximal cortical BD loss was observed between the 1 year (Ø -8%) and 3 year (Ø -22%) postoperative measurements. Distal to the trochanter minor no significant cortical BD changes were observed. Proximal cancellous BD decreased progressively between the 1 year (Ø -33%) and 3 year (Ø -45%) analyses. The Harris hip score improved from 45 points pre-operatively to 93 points at the 3 year follow-up. All x-rays showed signs of stable ingrowth.

CONCLUSION

Periprosthetic CT osteodensitometry has the technical ability to discriminate between cortical and cancellous bone structures with respect to strain-adapted remodeling. Progressive proximal cortical and cancellous BD loss indicates that metaphyseal fixation cannot be achieved with the analyzed C.F.P. stem design. The lack of cortical BD loss below the trochanter minor suggests diaphyseal fixation of the implanted stem.

Sonochemical growth of antimony selenoiodide in multiwalled carbon nanotube

This paper presents, for the first time, the nanocrystalline, semiconducting antimony selenoiodide (SbSeI) grown in multi-walled carbon nanotubes (CNTs). It was prepared sonochemically using elemental Sb, Se, and I in the presence of ethanol under ultrasonic irradiation (35 kHz, 2.6 W/cm2) at 323 K for 3 h. The CNTs filled with SbSeI were characterized by using techniques such as powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, high-resolution transmission electron microscopy, selected area electron diffraction, and optical diffuse reflection spectroscopy. These investigations exhibit that the SbSeI filling the CNTs is single crystalline in nature and in the form of nanowires. It has indirect allowed energy band gap EgIf=1.61(6) eV.

Biofeedback therapy for faecal incontinence: a rural and regional perspective

INTRODUCTION

Faecal incontinence is the involuntary loss of liquid or solid stool with or without the patient's awareness. It affects 8-11% of Australian community dwelling adults and up to 72% of nursing home residents with symptoms causing embarrassment, loss of self-respect and possible withdrawal from normal daily activities. Biofeedback, a technique used to increase patient awareness of physiological processes not normally considered to be under voluntary control, is a safe, conservative first-line therapy that has been shown to reduce symptom severity and improve patient quality of life. The Townsville Hospital, a publicly funded regional hospital with a large rural catchment area, offers anorectal biofeedback for patients with faecal incontinence, constipation and chronic pelvic pain. The aim of this report is to describe the effect of the biofeedback treatment on the wellbeing of regional and rural participants in a study of biofeedback treatment for faecal incontinence in the Townsville Hospital clinic.

METHODS

There were 53 regional (14 male) and 19 rural (5 male) participants (mean age 62.1 years) enrolled in a biofeedback study between January 2005 and October 2006. The program included 4 sessions one week apart, 4 weeks home practice of techniques learnt and a final follow-up reassessment session. Session one included documenting relevant history, diet, fibre, and fluid intake and treatment goals; anorectal function and proctometrographic measurements were assessed. Patients were taught relaxation (diaphragmatic) breathing in session two with a rectal probe and the balloon inserted, prior to inflating the balloon to sensory threshold. In session three, patients were taught anal sphincter and pelvic floor exercises linking the changes in anal pressures seen on the computer monitor with the exercises performed and sensations felt. Session four included improving anal and pelvic floor exercises, learning a defecation technique and receiving instructions for 4 weeks home practice. At the fifth session, home practice and bowel charts were reviewed and anorectal function was reassessed. Symptom severity and quality of life were assessed by surveying participants prior to sessions one and two and following session five. Patients were interviewed after session five to determine their satisfaction with the therapy and the helpfulness of individual program components. They were mailed a follow-up survey 2 years later.

RESULTS

Regional participants lived within 30 min drive of the clinic (median distance 8 km) while rural participants travelled up to 903 km (median 339 km, p<0.001) to attend the clinic. Faecal Incontinence risk factors were similar for rural and regional participants. Rural participants reported poorer general health (p=0.004) and their symptoms affected their lifestyle more negatively (p=0.028). Participants' incontinence (p<0.001) and quality of life (p<0.001) improved significantly over the treatment period. Improvement for rural participants over the course of treatment was marginally better than that of regional participants, although not significantly. More than 97% of patients reported that the biofeedback program was very/extremely helpful and all participants attending the final session reported that they would advise a friend in a similar situation not to wait, but seek help immediately, with more than half specifically citing the biofeedback program. Two years later regional participants' symptoms and quality of life continued to improve while rural participants' quality of life had regressed to pre-treatment levels.

CONCLUSIONS

For equivalent long term improvement in faecal continence and quality of life to be achieved in both regional and rural participants, an additional follow-up session with the biofeedback therapist, ongoing local support provided by continence advisors, or both, should be investigated for rural patients.

The influence of electroporation on in vitro photodynamic therapy of human breast carcinoma cells

Phototoxicity of drugs used in cancer photodynamic therapy could be augmented by increased accumulation of a photosensitizer in target cells. The intracellular delivery mode that enhances drug transportation could facilitate therapy by reducing the exposure time. Doses of the administered drug and related side effects could be lowered, whilst maintaining the same therapeutic efficiency. Electroporation supports transport of many drugs by creating electric field-induced transient nanopores in the plasma membrane. In this study, the electroporation- assisted transport of a photosensitizer was tested in vitro in human breast carcinoma cell lines: wild-type (MCF-7/WT) and doxorubicin-resistant (MCF-7/DOX). The efficacy of photodynamic therapy alone and in combination with electroporation was evaluated by cell viability with MTT test, using a haematoporphyrin derivative as a model. The data presented show up to 10-fold greater efficacy of the combined method, with very significantly reduced drug exposure times.

Using of sonochemically prepared components for vapor phase growing of SbI3.3S8

The using of sonochemically prepared components for growth of SbI(3).3S(8) single crystals from the vapor phase is presented for the first time. The good optical quality of the obtained crystals is important because this material is valuable for optoelectronics due to its non-linear optical properties. The products were characterized by using techniques such as X-ray crystallography, powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, high-resolution transmission electron microscopy, selected area electron diffraction, optical diffuse reflection spectroscopy and optical transmittance spectroscopy. The direct and indirect forbidden energy gaps of SbI(3).3S(8) illuminated with plane polarized light with electric field parallel and perpendicular to the c-axis of the crystal have been determined. The second harmonic generation of light in the grown crystals was observed.

First record of the black bullhead Ameiurus melas (Teleostei: Ictaluridae) in Poland

The North American catfish, the black bullhead Ameiurus melas, is recorded for the first time in Poland. The origin of these fish is not clear, but their presence may be associated with unregulated introductions by anglers.

Intestine as source of cytokines and growth factors

BACKGROUND

The activation status of intestinal immune system cells is much higher than that of analogous peripheral cells. Increased serum concentrations of proinflammatory cytokines have been reported in various pathologic conditions; however, the source of these mediators has not been elucidated.

OBJECTIVE

To assess the role of the human intestine and its lymphatic system in production of growth factors and proinflammatory cytokines.

MATERIAL AND METHODS

Twenty liver transplant recipients and 20 donors were included in the study. Blood samples were obtained from the artery supplying the intestine, the portal vein, and a peripheral vein during liver harvesting in donors and after transplantation in recipients. An enzyme-linked immunosorbent assay was used to assess serum concentrations of IL-6, tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta), and hepatocyte growth factor (HGF).

RESULTS

In transplant recipients, IL-6 concentration in arterial blood was lower than that in portal blood (P < .049), whereas in donors, there was no significant difference in these concentrations. Neither recipients nor donors demonstrated significant differences in arterial or portal blood concentrations of TNF-alpha, TGF-beta, or HGF.

CONCLUSIONS

In healthy human beings, the intestine is not a substantial source of IL-6, TNF-alpha, TGF-beta, or HGF. However, in patients with liver cirrhosis, the intestine is an important source of IL-6 but not of the other studied growth factors and cytokines.