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Biomedical subjects

S B Ogale

Publications and source records attributed to S B Ogale.

At least 19 recordsLinked to original sources
PubMed2003

High temperature ferromagnetism with a giant magnetic moment in transparent co-doped SnO(2-delta).

The occurrence of room temperature ferromagnetism is demonstrated in pulsed laser deposited thin films of Sn(1-x)Co(x)O(2-delta) (x<0.3). Interestingly, films of Sn(0.95)Co(0.05)O(2-delta) grown on R-plane sapphire not only exhibit ferromagnetism with a Curie temperature close to 650 K, but also a giant magnetic moment of 7.5+/-0.5 micro(B)/Co, not yet reported in any diluted magnetic semiconductor system. The films are semiconducting and optically highly transparent.

Journal Article↗
PubMed2003

Epitaxial BiFeO3 multiferroic thin film heterostructures.

Enhancement of polarization and related properties in heteroepitaxially constrained thin films of the ferroelectromagnet, BiFeO3, is reported. Structure analysis indicates that the crystal structure of film is monoclinic in contrast to bulk, which is rhombohedral. The films display a room-temperature spontaneous polarization (50 to 60 microcoulombs per square centimeter) almost an order of magnitude higher than that of the bulk (6.1 microcoulombs per square centimeter). The observed enhancement is corroborated by first-principles calculations and found to originate from a high sensitivity of the polarization to small changes in lattice parameters. The films also exhibit enhanced thickness-dependent magnetism compared with the bulk. These enhanced and combined functional responses in thin film form present an opportunity to create and implement thin film devices that actively couple the magnetic and ferroelectric order parameters.

Journal Article↗
PubMed2003

Demonstration of cytokeratin-5 non-expression in tobacco related oral carcinogenesis--use of reverse transcriptase polymerase chain reaction as a sensitive assay.

Cytokeratins (CK) are the epithelia specific intermediate filament proteins. We have shown consistent non-expression of CK-5 protein in human oral pre-cancer and cancer, in earlier studies. To investigate whether non-expression of CK-5 protein is the result of transcriptional or translational block and to evaluate the possibility if CK-5 non-expression can be used as a marker for early diagnosis of tobacco related oral cancer, RT-PCR using CK-5 specific primers was conducted. Out of 36 precancerous lesions and 29 squamous cell carcinomas (SCC) of buccal mucosa (BM) samples studied, 11 and 13 samples respectively of precancer and SCC did not show CK-5 product in RT-PCR. Down regulation of CK-5 mRNA expression was also observed in some samples. Thus, in conclusion, our results have shown that CK-5 non-expression is the result of transcriptional block. We proposed CK-5 non-expression as a potential marker for the early diagnosis of tobacco related oral cancer.

Carcinoma, Squamous Cell↗
PubMed2002

Expression of GSTM1 in angiofibromas.

The aetiology of juvenile nasopharyngeal angiofibroma (JNA) is largely unknown. In this study, we have investigated the expression of glutathione S transferase M1 (GSTM1) gene in angiofibroma. The GSTM1 allele gene locus is normally found in all human beings. When this is not expressed there is an increased risk of developing a malignancy of the upper aerodigestive tract. In this study, we have assessed eight samples of JNA for the expression of GSTM1, by the polymerase chain reaction (PCR) followed by polyacrylamide gel electrophoresis (PAGE), three of the eight patients studied failed to express this gene. Further investigation in this area is warranted.

Adolescent↗
PubMed2001

Electroresistance and electronic phase separation in mixed-valent manganites.

The sensitivity of transport in colossal magnetoresistance (CMR) manganites to external electric and magnetic fields is examined using field effect configurations with La(0.7)Ca(0.3)MnO(3) (LCMO), Na(0.7)Sr(0.3)MnO(3), La(0.7)Ba(0.3)MnO(3), and La(0.5)Ca(0.5)MnO(3) (0.5-doped LCMO) channels, and ferroelectric PbZr(0.2)Ti(0.8)O(3) (PZT) or dielectric (SrTiO(3)) gates. A large electroresistance (ER) of approximately 76% at 4 x 10(5) V/cm is found in LCMO with PZT-ferroelectric gate, but the magnitude of the effect is much smaller (a few percent) in the other three channels. The ER and CMR effects are remarkably complimentary. The size and systematics of the effect strongly favor a percolative phase separation picture.

Journal Article↗
PubMed2001

Difference in the dynamic scaling behavior of droplet size distribution for coalescence under pulsed and continuous vapor delivery.

Dynamic scaling behavior of the droplet size distribution in the coalescence regime for growth by pulsed laser deposition is studied experimentally and by computer simulation, and the same is compared with that for continuous vapor deposition. The scaling exponent for pulsed deposition is found to be (1.2 +/- 0.1), which is significantly lower as compared to that for continuous deposition (1.6 +/- 0.1). Simulations reveal that this dramatic difference can be traced to the large fraction of multiple droplet coalescence under pulsed vapor delivery. A possible role of the differing diffusion fields in the two cases is also suggested.

Journal Article↗
PubMed1998

Cytokeratin expression in precancerous lesions of the human oral cavity.

Cytokeratin (CK) expression was studied in buccal mucosa (BM) from 20 leucoplakia and 7 submucous fibrosis patients using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting and two-dimensional gel electrophoresis with iso-electric focussing (IEF) as the first dimension. Normal BM expresses CK 4, 5, 13, 14 and perhaps 19. Of 20 leucoplakia samples analysed, CK 5 was not detected in 17 samples, while CK 14 was not found in 13 samples. CK 1 and CK 8 were aberrantly expressed in six and seven samples, respectively. CK expression in contralaterally collected uninvolved tissues from 3 patients showed a normal pattern in two samples. Non-expression of CK 5 was observed in five of seven submucous fibrosis samples, while CK 14 was not detected in only two samples. CK 8 was aberrantly expressed in three samples. All the leucoplakia patients were chronic tobacco chewers. Thus, non-expression of CK 5 may be an early event occurring in tobacco-associated pathological changes in the BM.

Biomarkers, Tumor↗
PubMed1997

Fate of middle ear implants.

During the period 1981 through 1993, 613 cases out of a total of 4340 ear operations performed, needed ossicular chain reconstruction. This excludes stapedectomy operations. Out of 613 cases, 371 were cholesteatomatous and the rest were of safe chronic otitis media. Various graft materials used in ossicular reconstruction consisted of autologous ossicles or tragal cartilage, homologous preserved ossicles, cortical bone, human dentine, cadaveric styloid process and gold prosthesis. Results of the study show the extrusion rate of 1.54% with autologous ossicles, 1.43% with homologous ossicles, 1.19% with tragal cartilage, 3.61% with human cadaveric costal cartilage, 5.45% with cadaveric styloid process, 7.14% with dentine and 8.70% with gold prosthesis. These results are largely comparable with other studies. Natural graft materials like autologous and homologous ossicles have been found to have better take-up and long-term acceptance.

Audiometry, Pure-Tone↗
PubMed1994

The styloid process in ossicular chain reconstruction. II: Long-term analysis.

The human cadaveric styloid process was used as a homograft material for ossicular chain reconstruction in 41 cases of chronic suppurative otitis media over a five-year period. Although technical success was achieved in about 88.23 per cent of the cases, actual patient benefit was around 70.58 per cent; this is comparable to results obtained with most other homologous graft materials. The problem of breakage while remodelling the bone has also increased the risk of transmitting the AIDS virus and consequently undermines the use of this material.

Cadaver↗
PubMed1989

Profile of congenital cholesteatomas of the petrous apex.

Congenital cholesteatomas of the petrous apex are now frequently being approached by otologists. Involvement of the cerebello pontine angle by this lesion produces a myriad of signs and symptoms. Otological as well as neurosurgical literature is reviewed to achieve an overall understanding of the nature and behaviour of this uncommon but interesting lesion.

Bone Diseases↗
PubMed1988

Is vidian neurectomy worthwhile?

Vasomotor rhinitis is a frustrating experience both for the consultant and for the patient. The purpose of vidian neurectomy is to destroy the secretomotor nerve supply to the nasal mucosa, the main indication being severe intractable non-atopic vasomotor rhinitis. A review of 208 cases which have undergone transnasal vidian neurectomy by diathermy coagulation in the last five years is presented. The operation has proved worthwhile, the patients remaining symptom-free in 92 per cent of cases (longest follow-up 5 years). There have been no complications.

Adolescent↗
PubMed1988

The styloid process in ossicular chain reconstruction (a pilot study).

Our pilot study reports twenty-six cases of resolved chronic otitis media in which the human, cadaveric styloid process was used as an ossicular graft material. A maximum follow-up of one year is presented in this paper. There was no extrusion or rejection of the styloid processes. Hearing improvement with a closure of the air-bone gap to within 10-15 dB. of the pre-operative bone conduction was found in most cases. So far the styloid process has proved to be an ideal ossicular graft though the long-term results are yet to be seen.

Bioprosthesis↗