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Biomedical subjects

P Ramesh

Publications and source records attributed to P Ramesh.

At least 19 recordsLinked to original sources
PubMed2007

Hydroxyapatite moldable formulation using natural rubber latex as binder.

A simple but efficient processing method for shaping intricate bioceramic green bodies has been developed by using natural rubber latex as binder. Different shapes of hydroxyapatite Ca10(PO4)6(OH)2 (HAP) were molded from a composite formulation containing wet precipitated HAP, natural rubber latex (NRL), and a stabilizer. On controlled heat treatment followed by sintering, dense shapes of HAP contours were obtained. The thermal degradation profile of HAP-NRL composites shows that NRL degrades slowly without any abrupt exotherm. The results of energy dispersive X-ray analysis together with inductively coupled plasma (ICP) analysis indicate that the inorganic residue of NRL does not contain any heavy element. The sintered density of the samples increased with increased HAP content in the formulation and percentage shrinkage reduced accordingly. On varying the HAP content in the formulation from 35 to 95 wt %, the compositions with 85, 90, 92, and 95 wt % HAP showed better flexural strength in the range 40-54 MPa and a flexural modulus value in the range 36-50 GPa. The fracture morphology, as observed by the scanning electron microscope confirms that with increased HAP content in the formulation the sample microstructure attains higher uniformity. The Vickers microhardness for the samples sintered at two different temperatures (1150 and 1250 degrees C) showed that hardness increases with increase in the sintering temperature with a maximum for the highest HAP loaded formulation.

Biocompatible Materials↗
PubMed2006

Human osteosarcoma cell adhesion behaviour on hydroxyapatite integrated chitosan-poly(acrylic acid) polyelectrolyte complex.

A novel degradable composite system has been prepared by integrating hydroxyapatite, Ca(10)(PO(4))(6)(OH)(2), (HAP) in a polyelectrolyte complex matrix of chitosan (CHI) and poly(acrylic acid) (PAA). The composite was formulated by integrating 80 wt.% HAP in the polyelectrolyte complex matrix of CHI and PAA in the ratio 40/60 (designated as CPH). The composite could be easily fabricated into clinically significant shapes by a simple moulding procedure intended for bone graft applications. The adhesion behaviour of human osteosarcoma (HOS) cells on this degradable composite system was studied by selecting the polyelectrolyte complex, CHI/PAA 40/60 (designated as CP) as control sample. Light microscopic observations show that cells around CPH retained the typical morphology of HOS cells while cells around the polyelectrolyte complex showed a cytotoxic effect. The adhesion behaviour as well as morphological responses of the seeded cells was further investigated by scanning electron microscopy. The scanning electron micrographs of the polyelectrolyte complex, CP, showed the presence of rounded cells with raised nuclear regions, indicating delayed spreading; cells adhered on CPH were flattened with filopodia and showed good attachment and spreading, indicating better adhesion onto the HAP integrated composite. Comparing the MTT assay for quantitative evaluation of cell viability, CPH showed a higher percentage of metabolically active cells compared to CP.

Acrylic Resins↗
PubMed2005

Biological evaluation of pliable hydroxyapatite-ethylene vinyl acetate co-polymer composites intended for cranioplasty.

Hydroxyapatite (HAP) is undoubtedly a material suitable for repairing the defective bone tissue. However, the brittleness and non-malleability of HAP limit its clinical application as a cranioplastic analogue. To improve these properties, pliable, osteoconductive composites composed of HAP and ethylene vinyl acetate co-polymer (EVA) have been developed. This study reports the biocompatibility evaluation of the newly developed composite material. Composites of two compositions, containing 40 and 50 volume percentage of HAP, were evaluated. In vitro cell culture cytotoxity studies were carried out using L929 cell line. Intracutaneous irritation studies, and intramuscular implantation studies were carried out on rabbits. Cell culture studies showed that the composite was non-cytotoxic to mouse fibroblast cell line. Intracutaneous irritation studies did not show any gross signs of tissue reaction. Histological analysis after six months of implantation in the paravertebral muscles of rabbit showed that all the implants under study were covered with a thin soft tissue capsule. On the basis of these observations, we conclude that the composite materials are biocompatible and hence are a candidate material for implantation in the cranium.

Animals↗
PubMed2005

Buried Bumper Syndrome complicated by intra-abdominal sepsis.

There is growing evidence that enteral feeding tubes are associated with increased mortality and complication rates in patients with advanced dementia. Buried Bumper Syndrome is an uncommon, but well documented late complication of PEG placement. Our case report reinforces this recognised risk of PEG feeding in an elderly, cognitively impaired patient.

Abdomen↗
PubMed2004

Preparation and physicochemical and electrochemical characterization of exfoliated graphite oxide.

Exfoliated graphite oxide (EGO) is prepared by oxidizing exfoliated graphite (EG) using a mixture of KMnO(4)/H(2)SO(4). The physicochemical characterization of the EGO has been carried out using FT-Raman, FT-IR, XPS, NMR, and diffraction techniques. Colloidal form of EGO is subsequently prepared by ultrasonicating EGO in water. Thin films of EGO on a glassy carbon/gold surface are formed and the electrochemical and ion exchange properties have been studied using various redox systems such as K(4)[Fe(CN)(6)], ascorbic acid, and dopamine. The charge-based adsorption properties can be made use of, to either suppress or catalyze ascorbic acid oxidation. Adsorption and preconcentration of dopamine on the EGO film has been shown to electrocatalyze the oxidation of NADH.

Journal Article↗
PubMed2004

Comparative effectiveness of cattle manure, poultry manure, phosphocompost and fertilizer-NPK on three cropping systems in vertisols of semi-arid tropics. I. Crop yields and system performance.

A field experiment was conducted on deep vertisols of Bhopal, India to evaluate the manural potential of three organic manures: farmyard manure (FYM), poultry manure (PM), phosphocompost (PC) vis-a-vis 0%, 75% and 100% recommended dose of fertilizer-NPK and to find out the most productive cropping system at various combinations of organic manures and chemical fertilizers. The seed yield of intercrop soybean (population converted to 100%) was 8.7% less than sole soybean whereas the grain yield of intercrop sorghum was 9.5% more than that of sole sorghum. However, the productivity in terms of soybean equivalent yield (SEY) was relatively high in intercropping system. The increasing NPK dose from 0% to 100% significantly improved SEY in sole sorghum and soybean/sorghum intercropping system and the integrated use of organics and inorganics recorded significantly more SEY than inorganics. The effect of nutrient management followed the order; 75% NPK + 5 t FYM ha(-1) > 75% NPK + 1.5 t PM ha(-1) > 75% NPK + 5 t PC ha(-1) > 100% NPK. Sorghum, both as sole and intercrop, responded more to PM while soybean to FYM. Application of 75% NPK in combination with PM or FYM or PC to preceding rainy season crops (soybean and sorghum) and 75% NPK to wheat produced significantly higher grain yield of wheat than those in inorganics and control indicating noticeable residual effect on the succeeding wheat crop and saving of 25% fertilizer-NPK. The effect of PC on rainy season crops was not as prominent as those of FYM and PM, but its residual effect on grain yield of wheat was comparable to those two organic manures. Among the cropping systems, soybean as preceding crop recorded the highest seed yield of wheat and was on a par with that of soybean/sorghum intercropping system. The yield of wheat following sorghum was the lowest. The total system productivity (TSP) was the highest in sorghum + soybean-wheat system and the lowest in the soybean-wheat system.

Agriculture↗
PubMed2004

Angioleiomyoma: a clinical, pathological and radiological review.

Angioleiomyoma is a benign tumour arising from the vascular smooth muscle (tunica media) and presents commonly between third and fifth decades of life. Although there are sporadic reports about this tumour in the literature, none describes all the information in detail. This review is an attempt to collate all the facts in one concise article. Angioleiomyoma presents as a painful mass in approximately 60% of the cases. One of the distinct clinical feature noted is the increase in size of the swelling with physical activity of the involved part, especially in the hand. It should be considered in the differential diagnosis of painful nodular lesions of the extremity. Pre-operative diagnosis is difficult, but with a high index of suspicion and awareness, it is possible. The use of ultrasound and magnetic resonance imaging should be considered. It causes minimal morbidity and excision is usually curative. Histological examination using smooth muscle Actin stain portraits the smooth muscle bundles clearly.

Adult↗
PubMed2004

Can patients with dementia be assessed at a distance? The use of Telehealth and standardised assessments.

BACKGROUND: Telehealth could be a medium for the provision of cognitive assessments to distant sites. AIMS: The aims of the present study were to determine the interrater reliability of the Standardized Mini Mental State Exam (SMMSE) and the Geriatric Depression Scale (GDS) through Telehealth as compared to face-to-face administration. METHODS: Duplicate interviews of subjects with crossover of interview modality were carried out. Twenty patients were interviewed between two sites 11 km apart. Subjects were persons older than 65 years (mean age 82 years) who consented to Telehealth assessments. The outcome measures were the differences in assessment scores between the two media. RESULTS: The average SMMSE score by remote assessment was 24.0 (range 11.0-30.0) and by direct assessment was 24.3 (range 9.0-30.0). The correlation between direct and remote SMMSE scores was 0.90. The mean difference between direct and remote SMMSE scores was -0.3 (95% confidence interval (CI): -4.6 to 4.0). In 8 of 20 participants (40%) the difference between Telehealth and direct assessments was two points or more on the SMMSE. The average GDS by remote assessment was 6.1 (range 1.0-14.0) and by direct assessment was 5.8 (range 2.0-13.0). The correlation between direct and remote GDS scores was 0.78. The mean difference between direct and remote GDS assessment was 0.3 (95% CI: -3.8 to 4.4). CONCLUSION: Remote assessments with SMMSE and GDS using Telehealth methods yielded similar results to direct assessments. However, there was a moderate difference between face-to-face and Telehealth assessments in some subjects, which could influence clinical decision-making.

Aged↗
PubMed2003

Electrochemical characterization of binderless, recompressed exfoliated graphite electrodes: electron-transfer kinetics and diffusion characteristics.

Exfoliated graphite (EG) is prepared by the thermal exfoliation of graphite intercalation compounds at different temperatures. Surface and bulk physicochemical properties of EG are followed by spectroscopic and analytical methods and are observed to be a function of exfoliation temperature. EG particles can be recompressed without any binder and used as surface-renewable electrodes. Surface preparation is accomplished by either polishing or roughening the electrode surface using emery sheets. Effects of exfoliation temperature and the surface preparation on the electron-transfer kinetics and on the diffusion characteristics have been followed by electrochemical methods using several benchmark redox systems. It is found that the electron-transfer kinetics and the diffusion of K(4)[Fe(CN)(6)] are affected by the nature of the EG surface while that of iron(II)(1,10-phenanthroline)(3) and cobalt(II)(1,10-phenanthroline)(3) are not affected by the surface preparation. The redox systems are classified into different groups according to their kinetic sensitivity. Diffusion of electroactive species toward the EG electrodes is found to nonlinear. Current-time plots suggest that the recompressed EG electrodes can be modeled as fractals.

Journal Article↗
PubMed2002

Effect of vinyl acetate content on the sintering behavior of hydroxyapatite-ethylene vinyl acetate copolymer composites.

Ethylene vinyl acetate copolymer (EVA) alone could be used as a binder material for the fabrication of hydroxyapatite (HAP) into intricate shapes for various bone substitute applications. It was observed that as the vinyl acetate content in the polymer was increased from 12 to 28 wt % an increase in the sintered density of the HAP was observed. Retention of the shapes of HAP in the molded form was also observed.

Journal Article↗
PubMed2002

Microstructured microspheres of hydroxyapatite bioceramic.

Hydroxyapatite (HAP) particles having spherical geometry and 125-1000 microm in size range were prepared using a solid-in-water-in-oil (S/W/O) emulsion, cross-linking technique. An aqueous solution of chitosan containing different loading of HAP was dispersed as droplet in liquid paraffin using a stabilizing agent. Cross-linking of chitosan was induced by adding appropriate amount of glutaraldehyde saturated toluene. Chitosan microspheres containing HAP were sintered at 1150 degrees C to obtain pure HAP microspheres. The spheres thus produced were examined by scanning electron microscopy. The percentage yield and size distributions of the spheres were also determined.

Journal Article↗
PubMed2002

The clinical achievements of a geriatric telehealth project in its first year.

We performed a feasibility study to test the validity of conducting two standard cognitive assessments via videoconferencing. There was a high correlation between the scores from a face-to-face assessment and those from a videoconference. A second trial was conducted with patients living in a rural community, examined both face to face and via videoconferencing. Again, the validity and reliability of the assessment tools were demonstrated for videoconferencing. The acceptability of the technology to patients and clinicians was also shown. As a result of the trials and at the request of rural participants, geriatric telehealth services are now being provided to a rural aged care assessment team (ACAT) on a fee-for-service basis. The success of this project is reflected in its senior clinical and academic 'champions', the establishment of a dedicated telehealth resource and the development of protocols.

Journal Article↗
PubMed2002

The clinical achievements of a geriatric telehealth project in its first year.

We performed a feasibility study to test the validity of conducting two standard cognitive assessments via videoconferencing. There was a high correlation between the scores from a face-to-face assessment and those from a videoconference. A second trial was conducted with patients living in a rural community, examined both face to face and via videoconferencing. Again, the validity and reliability of the assessment tools were demonstrated for videoconferencing. The acceptability of the technology to patients and clinicians was also shown. As a result of the trials and at the request of rural participants, geriatric telehealth services are now being provided to a rural aged care assessment team (ACAT) on a fee-for-service basis. The success of this project is reflected in its senior clinical and academic 'champions', the establishment of a dedicated telehealth resource and the development of protocols.

Aged↗
PubMed2001

An immunosuppressive tryptophan-derived alkaloid from Lepidagathis cristata.

An immunosuppressive, tryptophan-derived alkaloid cristatin A (1), and two known compounds, cycloartenol and stigmasta-5,11(12)-diene-3 beta-ol, were isolated from the whole plant Lepidagathis cristata Willd. The structures of the isolates were established by interpretation of their spectral data.

Acanthaceae↗