Osseointegration of porous titanium and tantalum implants in ovariectomized rabbits: A biomechanical study

BACKGROUNDToday, biological fixation of uncemented press-fit acetabular components plays an important role in total hip arthroplasty. Long-term stable fixation of these implants depends on the osseointegration of the acetabular cup bone tissue into the acetabular cup implant, and their ability to withstand functional loads.AIMTo compare the strength of bone-implant osseointegration of four types of porous metal implants in normal and osteoporotic bone in rabbits.METHODSThe study was performed in 50 female California rabbits divided into non-ovariectomized (non-OVX) and ovariectomized groups (OVX) at 6 mo of age. Rabbits were sacrificed 8 wk after the implantation of four biomaterials [TTM, CONCELOC, Zimmer Biomet''s Trabecular Metal (TANTALUM), and ATLANT] in a 5-mm diameter defect created in the left femur. A biomechanical evaluation of the femur was carried out by testing implant breakout force. The force was gradually increased until complete detachment of the implant from the bone occurred.RESULTSThe breakout force needed for implant detachment was significantly higher in the non-OVX group, compared with the OVX group for all implants (TANTALUM, 194.7 ± 6.1 N vs 181.3 ± 2.8 N; P = 0.005; CONCELOC, 190.8 ± 3.6 N vs 180.9 ± 6.6 N; P = 0.019; TTM, 186.3 ± 1.8 N vs 172.0 N ± 11.0 N; P = 0.043; and ATLANT, 104.9 ± 7.0 N vs 78.9 N ± 4.5 N; P = 0.001). In the OVX group, The breakout forces in TANTALUM, TTM, and CONCELOC did not differ significantly (P = 0.066). The breakout force for ATLANT in the OVX group was lower by a factor of 2.3 compared with TANTALUM and CONCELOC, and by 2.2 compared with TTM (P = 0.001). In the non-OVX group, the breakout force for ATLANT was significantly different from all other implants, with a reduction in fixation strength by a factor of 1.9 (P = 0.001).CONCLUSIONTANTALUM, TTM, and CONCELOC had equal bone-implant osseointegration in healthy and in osteoporotic bone. ATLANT had significantly decreased osseointegration (P = 0.001) in healthy and in osteoporotic bone.     

Ultrasound-induced thermal elevation in clotted blood and cranial bone

Ultrasound thermal effects have been hypothesized to contribute to ultrasound-assisted thrombolysis. To explore the thermal mechanism of ultrasound-enhanced thrombolysis with recombinant tissue plasminogen activator (rt-PA) for the treatment of ischemic stroke, a detailed investigation is needed of the heating produced in skull, brain and blood clots. A theoretical model is developed to provide an estimate for the worst-case scenario of the temperature increase in blood clots and on the surface of cranial bone exposed to 0.12- to 3.5-MHz ultrasound. Thermal elevation was also assessed experimentally in human temporal bone, human clots and porcine clots exposed to 0.12 to 3.5-MHz pulsed ultrasound in vitro with a peak-to-peak pressure of 0.25 MPa and 80% duty cycle. Blood clots exposed to 0.12-MHz pulsed ultrasound exhibited a small temperature increase (0.25 degrees C) and bone exposed to 1.0-MHz pulsed ultrasound exhibited the highest temperature increase (1.0 degrees C). These experimental results were compared with the predicted temperature elevations.     

Sphenoid wing meningiomas: peritumoral brain edema as a prognostic factor in surgical outcome

Neurosurgical Review - Sphenoidal meningiomas constitute 18% of intracranial masses, and still present a difficult surgical challenge. PTBE has been associated with several complications and future...     

FIVE YEARS AFTER DEVELOPMENT OF THE NATIONAL DISABILITY,HEALTH AND REHABILITATION PLAN FOR UKRAINE: ACHIEVEMENTS AND CHALLENGES

In 2015, technical consultation to support development of the National Disability, Health and Rehabilitation Plan in Ukraine was carried out by the Rehabilitation Advisory Team of the International Society of Physical and Rehabilitation Medicine. Recommendations for actions and projects to improve rehabilitation services within the healthcare system in Ukraine were developed, proposed and implemented. The achievements in the subsequent 5 years include establishing, training and enabling employment at healthcare facilities for new rehabilitation professionals (physical and rehabilitation medicine physicians, physical therapists, occupational therapists), commencing implementation of the International Classification of Functioning, Disability and Health (ICF), and increasing rehabilitation knowledge among Ukrainian communities and decision-makers. The main challenges include inappropriate healthcare legislation for developing modern rehabilitation services, gaps in the clinical environment and quality control for training rehabilitation professionals, and the slow pace of implementation of the ICF. A general facilitator is the ongoing healthcare reform in Ukraine, especially its continuation to secondary and tertiary healthcare levels. Future high-priority activities will include amendments to basic healthcare legislation, and introducing a bio-psycho-social approach for the provision of rehabilitation services at all healthcare levels and all rehabilitation treatment phases, starting with the most debilitating health conditions. It will be important to continue the collaboration with European and international partners. LAY ABSTRACTUkraine developed a National Disability, Health and Rehabilitation Plan (NDHRP) in 2015. Since then, the recommended actions and projects have been implemented in the country. Some achievements can be seen, including the establishment of new rehabilitation professions (i.e. physical and rehabilitation medicine (PRM) physician and ergotherapist (the Ukrainian terminology for occupational therapist); implementation of the International Classification of Functioning, Disability and Health (ICF); and commencement of implementation of rehabilitation at different levels of healthcare. However, some challenges still need to be addressed, including the introduction of legislation to enable the delivery of effective and safe rehabilitation services, continuing education for rehabilitation professionals, and raising awareness of the ICF implementation, which is based on introducing a biopsycho-social model into the entire clinical process of rehabilitation. With the support of international partners, including European PRM bodies and other international organizations, the outlook for improvement in the field of rehabilitation in Ukraine is very positive. Key words: rehabilitation system, rehabilitation service, rehabilitation profession, rehabilitation service situation analysis, Ukraine, National Disability, Health and Rehabilitation Plan

Since Soviet times Ukraine’s healthcare system has retained a healthcare model with centralized funding, financing “for beds at hospitals”, paper medical records, and wide practice of out-of-pocket payments (1). A further problem is the systemic mistranslation and misuse of the term “healthcare” as “medical care”, starting from the level of legislation, and resulting in misunderstanding of healthcare by many generations of healthcare workers and the general public. At the same time, Ukraine had an inherited rehabilitation system, which was based predominantly on a bio-medical model of disability. Existing rehabilitation legislation in Ukraine still only covers populations with a certified disability (the Ukrainian term “invalidity” is assigned after special assessment by the Medical and Social Examination Commissions (MSECs)). The majority of rehabilitation measures focus on compensation of functional deficits and different kinds of social support provided through so-called invalidity groups. Since 2014 the armed conflict in eastern Ukraine has resulted in numerous injuries among military service personnel and civilians, and thus has greatly increased demands for rehabilitation services. For these reasons, the existing system of “medical rehabilitation” has collapsed, and the need for development of the National Disability, Health and Rehabilitation Plan (NDHRP) for Ukraine has become undeniable. The Ukrainian government (in particular the Ministry of Health of Ukraine; MoH) decided to implement the principles of the World Health Organization (WHO) Global Disability Action Plan 2014–2021 (GDAP; 2) by initiating a technical consultation to support development of the NDHRP in Ukraine. This was carried out by the Rehabilitation Advisory Team (RAT) of the International Society of Physical and Rehabilitation Medicine (ISPRM) in 2015 (3). The mission was based on the principles of the United Nations (UN) Convention on the Rights of Persons with Disabilities (4) and the World Report on Disability (WRD; 5). The goalsetting was derived from the WHO GDAP’s “Better Health for All People with Disabilities” (2), and the mission used the specially developed Rehabilitation Service Assessment Tool (RSAT; 6).The main findings from this mission included the absence of essential rehabilitation professionals in the country, a bio-medical approach to rehabilitation delivery, a complete discrepancy in meanings/translations and application of international rehabilitation-related terminology, and a lack of intersectoral coordination between the governing bodies responsible for the provision of rehabilitation services.     

Aldosterone and amiloride alter ENaC abundance in vascular endothelium

The amiloride-sensitive epithelial sodium channel (ENaC) is usually found in the apical membrane of epithelial cells but has also recently been described in vascular endothelium. Because little is known about the regulation and cell surface density of ENaC, we studied the influence of aldosterone, spironolactone, and amiloride on its abundance in the plasma membrane of human endothelial cells. Three different methods were applied, single ENaC molecule detection in the plasma membrane, quantification by Western blotting, and cell surface imaging using atomic force microscopy. We found that aldosterone increases the surface expression of ENaC molecules by 36% and the total cellular amount by 91%. The aldosterone receptor antagonist spironolactone prevents these effects completely. Acute application of amiloride to aldosterone-pretreated cells led to a decline of intracellular ENaC by 84%. We conclude that, in vascular endothelium, aldosterone induces ENaC expression and insertion into the plasma membrane. Upon functional blocking with amiloride, the channel disappears from the cell surface and from intracellular pools, indicating either rapid degradation and/or membrane pinch-off. This opens new perspectives in the regulation of ENaC expressed in the vascular endothelium.     

Bitumen Binders Modified with Sulfur/Organic Copolymers

With the continuing growth of waste sulfur production from the petroleum industry processes, its utilization for the production of useful, low-cost, and environmentally beneficial materials is of primary interest. Elemental sulfur has a significant and established history in the modification of bitumen binders, while the sulfur-containing high-molecular compounds are limited in this field. Herein, we report a novel possibility to utilize the sulfur/organic copolymers obtained via the inverse vulcanization process as modifiers for bitumen binders. Synthesis and thermal characterization (TGA-DSC) of polysulfides derived from elemental sulfur (S₈) and unsaturated organic species (dicyclopentadiene, styrene, and limonene) have been carried out. The performance of modified bitumen binders has been studied by several mechanical measurements (softening point, ductility, penetration at 25 °C, frass breaking point, adhesion to glass and gravel) and compared to the unmodified bitumen from the perspective of normalized requirements concerning polymer-modified bitumen. The interaction of bitumen binder with sulfur/organic modifier has been studied by means of FTIR spectroscopy and DSC measurements. The impact of the modification on the performance properties of bitumen has been demonstrated. The bitumen binders modified with sulfur/organic copolymers are in general less sensitive to higher temperatures (higher softening point up to 7 °C), more resistant to permanent deformations (lower penetration depth), and more resistant to aging processes without intrusive deterioration of parameters at lower temperatures. What is more, the modification resulted in significantly higher adhesion of bitumen binders to both glass (from 25% up to 87%) and gravel surfaces in combination with a lower tendency to form permanent deformations (more elastic behavior of the modified materials).