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GUEST EDITOR - Dr. T.S. Sampath Kumar, Indian Institute of Technology, Madras p 1-4 Full Text DEVELOPMENT
OF BIO-ACTIVE INTEGRATED OCULAR IMPLANT FOR ANOPHTHALMIC HUMAN PATIENTS B. Kundu, M. K. Sinha and D. Basu Hydroxyapatite
(HAp) powder was synthesized in the laboratory through wet chemical route
and mixed with naphthalene powder in 1: 3 w/w ratio, which was
homogenized, pressed iso-statically and subsequently turned to prepare
samples of predetermined size and shape. They were finally sintered at
1200 – 13000 C for 4 hrs. and were tested for different
physical, mechanical and tribological properties and used for clinical
trials to establish non-toxicity and bio-compatibility. The material in
granular form was introduced to Mongrel dogs and thereafter to human
patients for bone-grafting operations and the results are discussed.
Finally, out of these materials highly porous orbital implants of
different designs have been prepared and after thorough sterilization they
have been introduced to the Mongrel dog and subsequently to the
anophthalmic human patients after enucleation / evisceration surgery. The
results of the preliminary short-term clinical investigations are outlined
and performances are compared with that of the conventional ones. p 5-7 Full Text UHMWPE-ALUMINA CERAMIC COMPOSITE, AN IMPROVED PROSTHESIS MATERIALS FOR AN ARTIFICIAL CEMENTED HIP JOINT S.
K. Senapati and
S. Pal A
finite element analysis was undertaken on a simplified three-dimensional
model (Axisymmentric model) of a cemented hip prosthesis. Both stem and
bone are assumed to be rigidly connected by a layer of acrylic bone cement
(PMMA) and the layer taken are of constant cross section. The bone, cement
and the prosthesis materials are assumed as linear, elastic, isotropic and
homogenous. The influence of stem materials on the stem-cement interface
were evaluated using ANSYS 5.6 finite
element software. It was found that the peak values of the stem-cement
interface shear stress occurs either at the proximal or distal end of the
prosthesis and the peak interface stress at the prosthesis tip decreases
with decreasing prosthesis stiffness. p 8-11 Full Text DEVELOPMENT
OF CALCIUM PHOSPHATE COATINGS ON TYPE 316L SS AND THEIR IN
VITRO RESPONSE S.Kannan, A. Balamurugan and S. Rajeswari
p 12-14 Full Text SYNTHESIS AND CHARACTERISATION OF BIPHASIC CALCIUM PHOSPHATE E.
Caroline Victoria1 and F.D. Gnanam2 Clinical
application of pure bioactive hydroxyapatite can be improved with the
bioresorbable tricalcium phosphate for better bone regeneration. Biphasic
calcium phosphate (BCP) consisting of hydroxyapatite (HAp) and tricalcium
phosphate (TCP) has been processed by precipitation technique using 1.0 M
of Ca(OH)2 and 0.63 M of H3PO4. The X-ray
diffraction analysis of the as-dried powder reveals that the calcium
deficient hydroxyapatite is poorly crystalline and is converted into a
biphasic calcium phosphate when calcined at a temperature of 800oC.
The HAp and TCP ratio was found out to be 70 :30. The particle
agglomerates as determined form the laser diffraction method is found out
to be 2-3.0 mm.
The release of water and the decomposition of b-
Ca(PO3)2 to the pyrophosphate to form b
-TCP is evident from the thermal analysis. HPO42-
band is found in the FTIR of the as-dried sample. p
15-17
Full Text D.Siva
Rama Krishna1,2, C.K. Chaitanya1, S.K.Seshadri1
and T.S.Sampath Kumar1,2 Microwave
radiation was used to accelerate the formation of hydroxyapatite (HAp) by hydrolysis of b-tricalcium
phosphate(b-TCP).
The b-TCP
( b-Ca3(PO4)2
) powder was dispersed in distilled water and the aqueous solution
with or without hydrofluoric acid addition was exposed to microwave
radiation of 2.45 GHz for various times ranging from 5 to 40 minutes. The
products were characterized by X-ray powder diffraction method. The results show that the microwave radiation substantially
accelerates the hydrolysis reaction resulting in the formation of
partially fluorinated HAp. p 18-20 Full Text BIOACTIVE
SOL-GEL HYDROXYAPATITE SURFACE FOR BIOMEDICAL APPLICATIONS – IN
VITRO STUDY A
.Balamurugan, S.Kannan and S.Rajeswari Sol-gel
technology offers an alternative technique for producing bioactive
surfaces for improved bone attachment. In the present work HAP was
synthesized using the sol-gel technique and the solution was allowed to
age up to seven days prior to coating. It was found that , similar to
the wet-chemical method of HAP powder synthesis, an aging time is
required to produce a pure form of HAP phase. A methodology that has
been successfully used to produce hydroxyapatite thin film coatings via
the sol-gel route on 316L stainless steel is reported. Coatings
developed on 316L SS substrates were characterized by X-ray diffraction,
FT-IR, SEM and cyclic polarization studies for corrosion resistance. p 21-24 Full Text COMPARATIVE EVALUATION OF CHELATING GELS – INDIGENOUSLY DEVELOPED Vs COMMERCIALLY AVAILABLE Gopi
Krishna and A. Parameswaran Chelating
gels are employed by dentists for the removal of smear layer and debris
from inside the root canal.
Evaluation of indigenously developed EDTA gel for its quality of
chelating performance and potency with a commercially available gel.
This paper highlight various advantages of this indigenous gel in
the form of its comparable clinical efficiency, ease of manipulation and
lost effectiveness. p 25-27 Full Text IN
VITRO
EVALUATION OF INDIGENOUSLY DEVELOPED CYANOACRYLATES AS BONDING AGENTS IN
COMPARISON TO A CONVENTIONAL BONDING AGENT Amit Srivastava, Suresh Gorantla and
Ashima Valiathan The most widely adopted bonding systems use composite materials based on acrylic or diacrylate resins bonded largely by mechanical interlock with enamel, which has been pretreated with acid. Alternative bonding agents such as cyanoacrylates have been reported in literature. The aims of this study were to compare the bond strength of two indigenously developed cyanoacrylates with a conventional self-cured composite and to study the nature of the failure. The bond strengths` of Begg brackets bonded onto 90 freshly extracted premolar teeth was tested using an universal testing machine. Later ARI scoring was done to study the nature of the bond failure. The results showed that although the initial bond strength of N-Butyl cyanoacrylate was higher than the control composite, it deteriorated when stored in physiologic saline for 48 hours. Isoamyl-2-cyanoacrylate had significantly lower bond strength when compared to the other samples in all the three groups under study. ARI scores indicate that for both the composite and N-Butyl cyanoacrylate groups, the bond failure was adhesive (between the bracket and adhesive) where as for the Isoamyl-2-cyanoacrylate group, the bond failure was cohesive (between the adhesive itself). This study shows that further work needs to be done with cyanoacrylates to decrease their bio-degradability, so that they can be clinically useful in orthodontics. p 28-33 Full Text TISSUE
ENGINEERED BONE AND ADIPOSE TISSUE – AN IN
VITRO STUDY Annie John1, Yoshito
Ikada2 and Yasuhiko Tabata3 Bone marrow is a complex tissue composed of hematopoietic and stromal mesenchyme stem cells (MSCs) with a differentiation potential to adipogenic, fibroblastic, reticular, osteogenic and chondrogenic lineages. However, the number of multipotent MSCs of bone marrow cells rapidly decreases with donor age and thereby causes only limited tissue repair in adults. Therefore, considering the clinical application to hard and soft tissues, it is necessary to efficiently proliferate the MSCs without damaging their differentiation potentials. If osteogenesis and adipogenesis can be controlled from MSCs, it will be a therapeutic way to break through the problems involving breast and bone plastic and reconstructive surgeries. In the present study, we have studied the proliferation and differentiation of rat MSCs on substrates like polystyrene and polystyrene coated with - Type I and IV collagen and ProNectin F. We evaluated the addition effect of basic fibroblast growth factor (bFGF) on the proliferation of MSCs and that of dexamethasone (dex) and rh bone morphogenetic protein - 2 (rhBMP-2) on their osteogenesis. MSCs were also induced for adipogenesis by incubation in different adipogenic media containing insulin, methylisobutylxanthine and dex. The adhesion and proliferation of MSCs were enhanced in the presence of bFGF in the primary culture, and was significantly higher for the Type IV collagen, followed by ProNectin F and then the Type 1 collagen-coated substrate. The ALPase activity was high at the dex concentrations of 10-9 and 10-8 M for Type 1 collagen-coated and Type IV collagen-coated or polystyrene substrates and 10-7 M for ProNectin-coated plates. After 4 weeks of cells in culture, ALPase activity and calcium deposited on the different substrates were high on Type IV collagen compared to ProNectin F and Type 1 collagen-coated substrates. von Kossa stained mineralized plaques were visible. Increase in osteocalcin and ALPase levels were also high in Type IV collagen compared to ProNectin F and Type I-coated plates. On the other hand, adipogenesis was induced in MSCs at the dex concentration of 10-6 and 10-7 M. This change was more pronounced for Type IV collagen-coated substrates than the Type 1 collagen-coated substrates. However, ALPase activity was low in such adipogenic differentiated cultures. Adipocytes could be clearly identified by the presence of lipid vacuoles, as multilocular with small lipid inclusions or as unilocular adipocytes in foci containing single cells or few cells. p 34-37 Full Text CULTURE OF NEONATAL RAT LIVER CELLS: A PRELIMINARY OBSERVATION Anil Kumar PR, Bindu Menon, Anilkumar TV and Kumari TV As a therapeutic intervention to acute and chronic liver failure, many approaches like biological and non-biological liver support system are developed. In an extracorporeal hybrid liver support system, cultured hepatocytes/tissue in an artificial environment are used. For this hepatocytes have been isolated from liver of different organisms like rat, pig and also from human. In all these cases, the hepatocytes maintained in vitro tend to lose the biological function rapidly and hence their viability progressively decreases. A key point in biotechnology development is to develop culture system that can maintain cells for longer duration. Various methods are tried to increase viability of hepatocytes while maintaining its differentiated functions. Among those the source of hepatocytes is also very important. Normally hepatocytes isolated from adult rat liver by perfusion method can survive only upto maximum 5 days. If liver cells are isolated from embryo/neonatal organ, the longevity of cells increases. In this study, liver cells from neonatal rat survived upto 21 days. Preliminary observation of greater longevity of cells isolated from neonatal rat liver will be discussed. p 38-42 Full Text DESIGN AND DEVELOPMENT OF A SITE SPECIFIC, STIMULI SENSITIVE, CHITOSAN BASED NOVEL DRUG DELIVERY OF DUAL THERAPY FOR INFLAMMATION OF GUT T.K. Elangovan and S.V. Bhat Peptic ulcer in the gut is very common and their recurrence is also very common, which is very often due to Helicobacter pylori and hence very difficult to cure just by H2 antagonists or proton pump inhibitors, without eradication of H. pylori by an efficient antibiotic. Hydrogels having excellent swelling properties at the acidic medium could be a good candidate for this dual therapy with site specificity, high sensitivity, and safety without the side effects of the triple therapy. Hydrogels prepared from chitosan and poly vinylpyrrolidone were incorporated with Ciprofloxacin and Roxatidine and drug release pattern were studied. p 43-45 Full Text CONTROLLED
RELEASE OF ANTIBIOTIC FROM SURFACE MODIFIED CORALLINE HYDROXYAPATITE R. Murugan and K. Panduranga Rao A suitable method was developed to enhance the use of coralline hydroxyapatite (CHA) as carrier in drug delivery systems. CHA was surface modified by grafting with glycidylmethacrylate using redox initiators. FT-IR spectroscopy and X-ray diffraction were employed for the proof of grafting and phase purity of the graft copolymer. An antibiotic agent, gentamicin, was incorporated into unmodified CHA (UCHA) and surface modified CHA (SCHA). The percentage of loading and release profiles of gentamicin for UCHA and SCHA were evaluated and compared. It was found that the SCHA exhibited higher loading efficiency for gentamicin than the UCHA. In-vitro release profile of gentamicin was assayed by elution in phosphate buffered saline of pH 7.4 at 37°C. The in-vitro release of gentamicin from SCHA occurred up to 12 days, whereas it was 9 days for UCHA, for the release of most of the gentamicin incorporated. This prolonged release of gentamicin from SCHA was attributed to more interaction between the amino groups of gentamicin and epoxy groups. The results suggest that the SCHA coupled with gentamicin could serve as an effective method of administrating local chemotherapy primarily when used as a strut graft for bone defects. p 46-51 Full Text ADSORPTION OF IODINE ON NYLON-6 Jai
Paul Singhal and Alok R. Ray Antibacterial activity has been imparted to nylon-6 by adsorption of iodine. Iodine adsorption has been carried out by two ways: a) dipping nylon-6 fibers into solution of iodine in acetone and b) exposing nylon-6 fibers to iodine vapours. The amount of iodine adsorbed has been found to be very high as compared to theoretical amount of iodine required to form single layer on the surface of fibers. Iodine adsorption from solution in acetone does not follow Langmuir adsorption, but adsorption in vapour phase appears to follow pseudo-Langmuir adsorption isotherm. In case of adsorption of iodine from vapour phase, equilibrium is established between nylon-iodine complex and iodine vapours. However, in case of adsorption from solution, no such equilibrium appears to be established. This may be due to change in nature and ratio of different iodine species in the nylon-iodine complex. Possible mechanism of iodine adsorption has been discussed. |
