Trends in
Biomaterials & Artificial Organs
A biannual journal published by the 
Society for Biomaterials and Artificial Organs India
ISSN 0971-1198
Volume 17 Number 2 January 2004

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BIOETHICS AND BIOMATERIAL RESEARCH

Biomedical engineering has been largely responsible for many of the recent advances in modern medicine. However, along with the development of new medical technology, new moral and ethical issues have emerged. These include allocation of scarce resources, clinical trials of new devices and implants, conflicts of interest, and human and animal experimentation (1-4). Bioengineers need new adequate training and background in the principles of bioethics as they face medical ethics problems.

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AN OVER VIEW OF BIOINFORMATICS

Biology moves into silicon style. First there was in vivo biology then in vitro biology and now the discipline is moving in silico biology. Bioinformatics is the field of science in which biology, computer science, and information technology merge into a single discipline.

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Mechatronics & Robotics Laboratory, Department of Applied Mechanics 
Bengal Engineering College (Deemed University), Howrah - 711 103, West Bengal

Pressure distribution under foot during walking of a person depends on whether the Gait pattern is normal or abnormal. It also depends on weight of the body, age, and walking pattern, male or female etc. Therefore, two new parameters, dynamic foot-pressure variation from point to point (i.e. pixel to pixel), and movement of pressure centre are defined for normal and abnormal gait. The theoretical solution of the pressure distribution under the foot is extremely difficult due to complex behaviour of human tissues arising from viscoelasticity, non-linearity and non-homogeneity. Foot pressure patterns during walking are obtained by using an optical pedobarograph; for foot image formation, a CCD video camera for image capturing, a NI-IMAQ video digitiser hardware PC-add on card and LabView software with dedicated algorithms have been developed. The gray level image of ‘foot pressure distribution’ is divided into matrix form and the average value of each matrix element is determined in pseudo gray colour, which provides information about the degree of abnormality of the foot. For normalised pressure distribution, a new parameter called “pressure index” has been introduced. Knowledge of pressure distributions from gray scale image data of all the points on the planter surfaces of both feet along with EMG test results can provide suitable guidelines to biomedical engineers and doctor for designing orthotic devices, rehabilitative foot wear and conducting corrective foot surgery of neuropathic feet for reliving the area of excessively high localised pressure and distribute body weight evenly.

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Cryogenic is the physics and engineering of low temperatures, wherein cryobiology uses these techniques for advancing agricultural and medicinal activities. They are being used for preservation of sperms of rare species, plant, seeds, cell lines (eukaryotic and prokaryotic) and tissues. The most recent development in the field of cryogenics is the study of bioenergetics in living cells at normal and subzero temperatures and the preservation of plasma, cord blood cells, organs, transplantations and in vitro fertilisations. The author highlights few of those entropy related cooling activities of cells and tissues and their genetical variations, while preserving at subzero temperatures and to analyse the mutational effects of genes, the Activation energy and Arhenius, the molecular reactions in a frozen cell and tissues release water and accumulate at” danger zone”, by membrane electron transport in lipid bilayers to describe and how a cooling of cells and tissues work at subzero-temperature.

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In the present work we report the simple poly (methyl methacrylate) polymer preparation, characterization and its use in the fabrication of intraocular lens (IOL). Methyl methacrylate (MMA) was polymerized by photo initiated polymerization technique using direct sunlight and UV light λ280 nm. The polymerized material PMMA was characterized fully for its usefulness as an intraocular lens by various techniques. FT-IR and 13C-NMR was performed to find out the total conversion of MMA monomer into polymer. Molecular weight was determined by GPC and the thermal properties were studied by TGA, DTA, and DSC. The % Transmittance of light (%T) and Refractive Index (RI) were studied by U.V. Spectrophotometer and Refractometer respectively. Mechanical properties like tensile strength and Young’s modulus were also studied. The results obtained from the above experiments indicated that the total conversion of MMA monomer into polymer with good mechanical and thermal properties. The RI was found to be 1.487 and %T was about 78% in 250-500 nm range. Finally the material was fabricated according to the IOL specifications and was compared with the commercially available IOL.

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Central Leather Research Institute, Adyar, Chennai - 600 020, India

Human amnion as temporary biological wound dressing has remained as beneficial and cost effective means of treating burns in developing countries. In the present research work, an effort has been made to chemically modify the human amnion by cross linking the protein with glutaraldehyde and later graft copolymerizing with poly hydroxyl ethyl methacrylate (PHEMA) using potassium persulphate and sodium metabisulphate as initiators. The products developed were characterized for their water absorption capacity, mechanical strength, infrared spectroscopy, and thermo gravimetric analysis. The results have shown that the water absorption capacity and tensile strength of native amniotic membrane are higher than all the other samples. Infrared spectra have clearly shown the cross linking and grafting of amniotic membrane with glutaraldehyde and PHEMA respectively. It is observed from thermogravimetric analysis that the cross linked amniotic membrane has more thermal stability than the native membrane. Further it is deduced that the percentage of grafting of PHEMA is higher with crosslinked membrane. Even though the mechanical strength and water absorption capacity of chemically modified human amnion are lesser than the native amniotic membrane the same can be used as a hydrogel. As the material is crossed linked with glutaraldehyde it can be stored for a long time.

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Bio-products Laboratory, Central Leather Research Institute, Adyar, Chennai-600 020. 
1 School of Bioscience and Engineering, Jadavpur University, Kolkata -700 032.
2 Dept. of Radiology and Surgery, College of Veterinary Science, Tirupathy - 517503.

A bio-inorganic composite of deglued bone, chitosan, and gelatin was prepared as a substitute for autologous bone graft and evaluated in vivo using dog as experimental model. The animal experiment was evaluated by biochemical, radiography, and histo pathological studies. The serum was tested for its calcium, inorganic phosphorous and alkaline phosphatase contents at different stages of bone healing. Radiographs of experimental bone were taken at the interval of three weeks after implantation. The histopathological study of bone tissue at the defect site was carried out by euthanising the animals each at the interval of three weeks post operatively. The results had showed that there was no significant change in serum calcium and phosphorus levels during different stages fracture healing. But there was a highly significant elevation in serum alkaline phosphatase (ALP) level in all the animals up to 3rd post-operative week. Plain radiographs and photomicrographs had showed that there was no host rejection or periosteal reaction and at 9 weeks post-operative, a complete union of defect was noticed. The biomaterial developed in the laboratory, was well accepted by the host and induced bone growth.

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*Department of Metallurgical Engineering
+Regional Sophisticated Instrumentation Centre
Indian Institute of Technology Madras, Chennai-600036.

Bioactive coatings on metallic implants facilitate joining between the prosthesis and the osseous tissue, and increase the long-term stability and integrity of the implant. Literature suggests that current coating techniques provide inadequate adherence of the coating to the implants. A processing schedule was developed that minimizes reactions and produces thin coatings with the substrate. Hydroxyapatite and biphasic calcium phosphate (combination of hydroxyapatite and tri-calcium phosphate) coatings were carried out on 316L stainless steel implant material by a simple dip-coating method. Prior to the coating the substrate surfaces were passivated. The dip-coated implant materials were subsequently heat treated at appropriate temperatures for improving coating adhesion to the substrate. The coated implant materials have been characterized by X-ray diffraction, scanning electron microscopy and adhesion test. The results show that the dip coated hydroxyapatite and biphasic coatings of thickness of about 5-7 micron strongly attach to the 316L stainless steel substrates.

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Due to its complex geometry and structure, the biomechanics of the pelvis is complicated. The Finite Element Method (FEM) may be used to analyze this type of very complex geometries. To get the realistic results, it is desired that the finite element analysis (FEA) have to be accomplished with a three-dimensional model similar to the shape and architecture of the pelvic bone. Our present study was aimed at developing a realistic three-dimensional finite element model of the pelvis and finding out the stress pattern of the pelvic bone during normal walking specially in the area around the pubic ramus and the acetabular cavity. This was a preliminary study applying simple walking load. After this study, the effect of heavy impact load due to car accident etc. will be analyzed.

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Mechanical testing is common methodology to evaluate the performance of implant materials. Various types of loads were applied to the appropriate test samples and its mechanical properties were measured. Sufficient strength and stiffness, biocompatibility and long-term stability are important criteria that ultra high molecular weight polyethylene (UHMWPE) and its composites have to fulfill for successful implant application in bone surgery. An additional important requirement is sterilization, without degradation of these biomaterials, was also studied.

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Mechanical properties of scapular trabecular bone are assumed to be similar to those of other trabecular bone of different anatomical regions, like tibia, femur, humerus. The goal of this study was to develop a technique that may be useful to detect bone geometry and pixel gray value from contour data of CT-scan slice of the scapula. In this paper an attempt has been made to relate quantitative Computed Tomography (CT) gray values with apparent density, and apparent density with elastic modulus. A contour detection algorithm has been developed that finds the optimised bone contour by connecting the points with high derivatives of CT gray value on lines perpendicular to an initial contour. The number of points in a contour were stored as keypoints which were useful for generating a three-dimensional model of the scapula. A linear regression, generalised for all CT-scan slices defining the whole scapula, was derived from two reference points (one nobone condition, i.e. air, another cortical bone). Based on structural and analytical models of trabecular bone, power law relations were fitted for two ranges of apparent density. Powers of 2 and 3 (E ~ ρ2, E ~ ρ3) have been used for open cell rod-like structure and closed cell plate-like structure, respectively. The transition from open to closed structure was assumed to occur at an apparent density of 350 kg m-3. The theoretical relationships were fitted to experimental data of glenoid cancellous bone specimens. The above-mentioned relationships for scapular trabecular bone are meant to be used for a finite element model of a scapula, with or without an implant, based on CT-scan images.

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Coronary stents are developed and used to overcome the two major limitations of balloon angioplasty, acute occlusion and long-term stenosis. Even with the use of stent, stenosis remains a major limitation. It has been felt that a controlled release of drugs that inhibit the mitogenicity and proliferation of vascular smooth muscle cells (VSMC) at the stent implantation site should reduce the restenosis at the site of stent implantation. Different methods have been used for immobilization of drugs with stent to get an effective concentration to inhibit the cell proliferation.

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Our team has been working on the problem of human fetal tissues' response to antigenic assaults, for the last two decades. In the present series, 12 patients with prolonged histories of Parkinsonism, who were not responding to anti-Parkinsonian drugs were enrolled for the study. What is intriguing is the survival, growth and proliferation of the grafted fetal brain tissue. Not a single histological study of the fetal brain tissues after removal from the axilla, showed any signs of graft vs. host or inflammatory reaction ( Microphotograph 1-9) but there are features of growth of the transplanted cortical brain tissue along with its different components like neurogenesis, gliogenesis early neovascularisationand, angiogenesis etc., neither there was any systemic leucocytosis or lymphocytosis. Following ethical clearance fetal brain tissue was grafted in the HLA and sex randomized adult axilla, without any immunosuppressive support. Histological evidences at the transplanted tissue site suggest that the fetal cortical brain tissue can sustain a living in sex randomized, HLA randomized adult hosts, without the support of immuno-suppressive drugs and the tacit support of the blood-CSF and blood-brain barrier and other specific requirements of adult brain cells in the skull. Whether the clinical improvement in PD is transient or long lasting is presently under investigation along with basic questions like is it due to transplanted fetal dopaminergic or non- dopaminergic neurons or the growth factors and the cytokine mediated hitherto unknown reactions causing the clinical improvement.

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The present study was aimed at examining the role of developing fetal adrenal transplant in cases of old rheumatoid arthritis with severe pain due to involvement of the inflammatory and neuropathic components of pain. Human fetal adrenal transplant survives in HLA randomized adult hosts with rheumatoid arthritis and has a beneficial effect on pain and inflammation.

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The successful development of fetal cell/tissue transplantation in adults has resulted in the possibility of eventual therapeutic solution with a variety of intractable diseases. Umbilical cord whole blood transplantation appears to be safe in the adult system. In severe forms of DiGeorge Syndrome, cultured thymus transplant can help in the reconstitution of the immune condition of the host. Successful fetal tissue transplant in adults, raised the hope of future effective gene transplant and its manipulation prospects to combat many diseases including hemopathies, inborn errors of metabolism, immunodeficiencies and even in cancer and AIDS. Two cases of advanced cancer were treated with fetal (pre-immune 12 weeks and hypoimmune 16 weeks) thymus transplant in subcutaneous vascular axillary fold, which were removed after one month. Thymuses were collected from consenting mothers undergoing hysterotomy and ligation. Pre-immune and hypo-immune human fetal thymic transplant is not rejected in patients suffering from advanced cancer within one month (observation period). Thymic lymphocytes' shedding in the correction of leucopenia in the background of non-Hodgkin's lymphoma may have many therapeutic implications.

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The art of transplant surgery has come a long way in establishing itself as an important discipline with the support of immunology, molecular biology, etc., for the restoration of the function of a failing organ. Today, there is a major discrepancy in the demand and supply of adult organ grafts. The aim of the present study is to examine whether fetal tissue/ organ, with its intrinsic advantage of hypo-antigenicity as well as its rich organ specific stem cell content, can survive in a HLA and sex randomized host in a heterotopic site without any immunosuppressive support.

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*Bijoygarh State Hospital,Kolkata- 700 032, **Dept. of Medicine, IPGMER.
***Dept. of Science & Technology, Govt. of West Bengal.#, Jadavpur University., 

174 units or umbilical cord whole blood was collected aseptically from the umbilical vein after caesarean section in standard pediatric blood transfusion bags,* after the removal of the baby from the operative field and after confirming the stable condition of the mother. The volume of cord blood varied from 50ml. to 140ml. with mean 86ml (16ml SD. On the basis of our experience with 174 units of placental umbilical cord whole blood transfusion in malignant and non-malignant conditions (within three days of collection and preservation, at 1-60C, in a refrigerator), we are of the opinion that this is a safe transfusion protocol, which takes advantage of the safety of nature's finest biological sieve, i.e., the placenta, as an alternative to adult whole blood transfusion. It also has the advantage of a higher oxygen carrying capacity of fetal hemoglobin in addition to many growth factors and other cytokine filled cord blood plasma along with its hypoantigenicity.

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Department of Applied Mechanics, Bengal Engineering College (Deemed University)
Howrah-711 103, West Bengal, India
shamiksarkarcap@rediffmail.com*

The development of additional protection systems for head, most vulnerable to traffic or industrial accidents, needs advanced knowledge on head injury mechanics. In this study, we tried to obtain insight of it by modeling finite element skull-brain complex and find out the stress pattern under static and dynamic load. In our research, models of the human head & skull were developed using the CT Scan data. The model consisted of 1945 elements through 3992 nodes. It was observed that the maximum von-Mises stress was around 1.97 MPa and maximum shear stress was 0.64 MPa that occurred in brain stem. Ruan et al. (1994) also observed that brain stem is most vulnerable to shear. Total stress contour map revealed that the average von-Mises stress generated in most of the areas was below 0.22 MPa. In case of the skull, level of von- Mises stress was much higher. The maximum von-Mises stress obtained adjacent to the CSF was 1.96 MPa.

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*Department of Applied Mechanics, Bengal Engineering College (a Deemed University), 
Howrah-711103 
**School of Bio Sc. & Engineering, Jadavpur University, Calcutta-700032 

It is observed that the main cause of failure of implants in human body is component loosening. This phenomenon happened due to the presence of wear debris in the bone implant interface and implant bone cement interface. These wear debris is generated due to surface rubbing of two parts of the implants. These parts are mainly made of UHMWPE, ceramics and metallic alloys. To avoid the implant failure, minimization of generation of wear debris was the main goal of this study. We fabricated a reciprocating type wear testing machine according to ASTM protocol. Different types of frequently used implant biomaterials pairs were considered for testing. We considered UHMWPE and ceramics as a pin and Co-Cr-Mo alloy, titanium and ceramics as a plate above which pin rubs. Rubbing speed was 25mm/sec. Results observed in case of titanium and titanium alloy were not better than above two cases. Stainless steel had shown worse performance. For Co-Cr-Mo alloy and UHMWPE pair, the amount of wear debris generated was lesser than the others.

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S K Senapati & S.Pal
School of Biosc, & Engg, Jadavpur University, Kolkata-700032
Email: bioengg@giasclo1.vsnl.net.in

Various prostheses and total joint replacements evolved over the past hundred years through a continuous worldwide effort to seek solution to a problem as old man himself. Historically in 1891 an ivory ball and socket joint was designed by Gluck in Germany , which was fixed with nickel-plated screws. Subsequently many more surgeons, scientists worked on hip joint replacement and more then 160 types of prostheses were developed till today.