Phosphate functionalized and lactic acid containing graft copolymer: synthesis and evaluation as biomaterial for bone tissue engineering applications

Polyvinyl alcohol (PVA) and polylactic acids (PLA) are biocompatible materials possessing some inherent contrasting limitations which have reduced the scope of their individual applicability. Specifically, overcoming strong hydrophobicity and introducing chemical groups for biofunctionalization are unmet challenges for PLA whilst chemical endeavors to render adequate aqueous stability and cell adhesion properties to PVA have not produced completely intended results. Objective of the present work is to explore synthesis of a graft polymer as an approach towards coupling biofunctional groups with PLA materials. In a two-step reaction, PPVA (phosphorylated polyvinyl alcohol or PVA pre-functionalized with phosphate) is esterified with lactic acid followed by polymerization into PLA in presence of stannous chloride as catalyst to obtain phosphorylated polyvinyl alcohol-graft-polylactic acid (PPVA-g-LA) copolymer. Product is characterized by nuclear magnetic resonance, X-ray diffraction, and thermogravimetric analysis. PPVA-g-LA shows an increase in uniaxial elongation compared to parent PPVA under condition of tensile loading. The graft copolymer also exhibits higher water contact angles compared to PPVA, but a more hydrophilic surface compared to PLA. Culture of MG-63 cells on solvent cast films of polymers demonstrates that PPVA-g-LA as a cell substrate can significantly (p?<?0.05) improve proliferation and differentiation of cells compared to PPVA substrate whereas in comparison to PLA can significantly ameliorate osteoblast function of cultured cells. Overall, results illustrate the feasibility of PVA to act as a carrier for biofunctional agents to be coupled to lactic acid-based biomaterials with subsequent improvement in cell response on the polymers. In this attempt, it also affords materials with tunable surface or bulk properties of relevance for tissue engineering applications.     

Selbstlimitierende fokale Epilepsien aus dem Parietal- und Okzipitallappen im Kindesalter

Clinical Epileptology - Den selbstlimitierenden fokalen Epilepsien im Kindesalter, eine heterogene Gruppe von Epilepsiesyndromen, sind fokale epileptische Anfälle ohne strukturelle Ursache,...     

Chronic intestinal pseudo-obstruction: systematic histopathological approach can clinch vital clues

The histopathological approach of chronic intestinal pseudo-obstruction (CIP) is critical, and the findings are often missed by the histopathologists for lack of awareness and nonavailability of standard criteria. We aimed to describe a detailed histopathological approach for working-up cases of CIP by citing our experience. Eight suspected cases of CIP were included in the study to determine and describe an approach for reaching the histopathological diagnosis collected over a period of the last 1.5 years. The Hirschsprung’s disease was put apart from the scope of this study. A detailed light microscopic analysis was performed along with special and immunohistochemical stains. Transmission electron microscopy was carried out on tissue retrieved from paraffin embedded tissue blocks. Among the eight cases, three were neonates, one in the pediatric age group, two adolescent, and two adults. After following the described critical approach, we achieved the histological diagnoses in all the cases. The causes of CIP noted were primary intestinal neuronal dysplasia (IND) type B (in 4), mesenchymopathy (in 2), lymphocytic myenteric ganglionitis (in 1), and duplication of myenteric plexus with leiomyopathy (in 1). Desmosis was noted in all of them along with other primary pathologies. One of the IND patients also had visceral myopathy, type IV. Histopathologists need to follow a systematic approach comprising of diligent histological examination and use of immunohistochemistry, immunocytochemistry, and electron microscopy in CIP workup. Therapy and prognosis vary depending on lesions identified by pathologists. These lesions can be seen in isolation or in combinations.     

Acute Hemorrhagic Edema of Infancy

The authors report an 11-mo-old child presenting with acute onset appearance of large, erythematous, palpable purpuric lesions involving face, extremities and trunk. Skin biopsy from the margin of the lesions showed leukocytoclastic vasculitis suggesting a diagnosis of acute hemorrhagic edema of infancy. This rare type of cutaneous vasculitis, despite its grave presentation is a benign condition with self-limiting course.     

Custom-made rotating hinge total knee replacement in a patient with congenital tibial deficiency avoids the need for amputation

We report a unique case of a patient with type 2 congenital tibial deficiency and disabling knee osteoarthritis in whom a custom-made rotating hinge knee replacement was successfully performed, allowing continued mobilisation with a below-knee prosthesis, thereby avoiding the need for an above-knee amputation. Level of evidence Therapeutic study, Level IV.     

The safety of direct primary excision of low-grade chondral lesions based on radiological diagnosis alone

The safety of treating low-grade chondral tumours by primary surgery without a pre- operative diagnostic needle biopsy was assessed by looking at the concordance between radiological and histological diagnoses. A retrospective review of the departmental histopathology registry from 2005 to 2009 was performed to identify cases of intramedullary chondral lesions in the appendicular skeleton. Cases with a pre-operative needle biopsy and with recurrence were excluded. Correlation between radiological and histological diagnosis was investigated with kappa analysis. Of 53 patients, bone expansion was seen in 18.4%, endosteal scalloping in 42.9% and extraosseous extension in 143%. Concordance was 100% between the radiological and histological diagnoses (Kappa score = 1.0). If a radiological diagnosis of an enchondroma or low-grade chondrosarcoma is made, then direct surgical treatment without needle biopsy is safe. A biopsy should be considered if any atypical radiological features suggesting a high-grade chondrosarcoma exist. This increases the certainty of diagnosis and allows planning of surgical treatment.     

Variability in protocols on donation after circulatory death in Europe

Introduction

Organ donation after circulatory death (DCD) has become an accepted strategy to reduce the shortage of organs for transplantation in many European countries. The use and number of DCD donors varies between countries. The purpose of this study was to evaluate the available protocols for DCD in Europe.

Methods

We contacted national transplant societies and responsible transplant co-ordinators in the countries that perform DCD to obtain DCD protocols. We compared information on the protocols and additional data including: inclusion and exclusion criteria for donation, legislation, determination of death and preservation methods.

Results

In ten European countries DCD is performed, eight of which describe the methods in protocols. There are large differences in used DCD categories, legislation and the way death is determined. Protocols differ in the detail in which DCD procedures are described and the way methods are supported by additional consensus statements and ethical frameworks.

Conclusions

Although DCD is an established strategy to enlarge the donor pool and to contribute to the reduction of the waiting list for transplantation, its potential has not been fully utilized yet. To further promote DCD transplantation, it is important to share expertise and obtain consensus, so that this can be translated into more uniform and solid protocols supported by the competent authorities, transplant and intensive care professionals, which may eventually result in a further promotion of DCD transplantation in Europe.