A study on the effect of bioactive glass and hydroxyapatite-loaded Xanthan dialdehyde-based composite coatings for potential orthopedic applications

The most important challenge faced in designing orthopedic devices is to control the leaching of ions from the substrate material, and to prevent biofilm formation. Accordingly, the surgical grade stainless steel (316L SS) was electrophoretically deposited with functional composition of biopolymers and bioceramics. The composite coating consisted of: Bioglass (BG), hydroxyapatite (HA), and lawsone, that were loaded into a polymeric matrix of Xanthan Dialdehyde/Chondroitin Sulfate (XDA/CS). The parameters and final composition for electrophoretic deposition were optimized through trial-and-error approach. The composite coating exhibited significant adhesion strength of "4B" (ASTM D3359) with the substrate, suitable wettability of contact angle 48°, and an optimum average surface roughness of 0.32 µm. Thus, promoting proliferation and attachment of bone-forming cells, transcription factors, and proteins. Fourier transformed infrared spectroscopic analysis revealed a strong polymeric network formation between XDA and CS. scanning electron microscopy and energy dispersive X-ray spectroscopy analysis displayed a homogenous surface with invariable dispersion of HA and BG particles. The adhesion, hydrant behavior, and topography of said coatings was optimal to design orthopedic implant devices. The said coatings exhibited a clear inhibition zone of 21.65 mm and 21.04 mm with no bacterial growth against Staphylococcus aureus (S. Aureus) and Escherichia coli (E. Coli) respectively, confirming the antibacterial potential. Furthermore, the crystals related to calcium (Ca) and HA were seen after 28 days of submersion in simulated body fluid. The corrosion current density, of the above-mentioned coating was minimal as compared to the bare 316L SS substrate. The results infer that XDA/CS/BG/HA/lawsone based composite coating can be a candidate to design coatings for orthopedic implant devices.

Presenting features in Pakistani patients suffering from the antineutrophil cytoplasmic antibody--classical subtype (c-ANCA) associated vasculitis

OBJECTIVES

To study the clinicopathological features in c-ANCA positive patients suffering from vasculitis with a view to find out the most common mode of presentation.

STUDY DESIGN

Retrospective.

SETTINGS

Department of Immunology, AFIP, Rawalpindi, MH Rawalpindi, CMH Rawalpindi, Department of Rheumatology, PIMS, Islamabad, RGH Rawalpindi, FFH, Rawalpindi.

SUBJECTS

Seventeen patients suffering from vasculitis and found to be positive for c-ANCA.

MAIN OUTCOME MEASURES

Clinico-pathological features at presentation.

RESULTS

There were 9 males in age range 11-60 years (mean age 32.5 years) and 8 females in age range 26-42 years (mean age 32.3 years). Common presenting features were a combination of cough, blocked nose and post nasal drip 14/17 (82%) followed by nose bleed and haematuria 11/17 (65%). Six patients were demonstrated to be suffering from Wegener's granulomatosis after biopsy. C-ANCA was detected by indirect immunofluorescence in the titre range of 8-640. The auto antibody levels related to disease activity.

CONCLUSION

c-ANCA associated vasculitis is a rare (17 patients in five years) but aggressive form of vasculitis. It must be suspected in patients with persistent respiratory tract related symptoms associated with fever and joint pains which fail to respond to adequate treatment for infections. The c-ANCA estimations can be utilised as sensitive and specific diagnostic and prognostic marker in this form of vasculitis.