Magnetic and Magnetostrictive Properties of Sol-Gel-Synthesized Chromium-Substituted Cobalt Ferrite.

Chromium (Cr)-doped cobalt ferrite nanoparticles were synthesized using a sol-gel autocombustion method, with the chemical formula CoCrxFe2xO4. The value of x ranged from 0.00 to 0.5 in 0.1 increments. X-ray diffraction analysis confirmed the development of highly crystalline cubic spinel structures for all samples, with an average crystallite size of approximately 40 to 45 nm determined using the Scherrer equation. Pellets were prepared using a traditional ceramic method. The magnetic and magnetostrictive properties of the samples were tested using strain gauge and VSM (vibrating sample magnetometer) techniques. The results of the magnetic and magnetostrictive tests showed that the chromium-substituted cobalt ferrites exhibited higher strain derivative magnitudes than pure cobalt ferrite. These findings indicated that the introduction of chromium into the cobalt ferrite structure led to changes in the material's magnetic properties. These changes were attributed to anisotropic contributions, resulting from an increased presence of Co2+ ions at B-sites due to the chromium substitutions. In summary, this study concluded that introducing chromium into the cobalt ferrite structure caused alterations in the material's magnetic properties, which were explained by changes in the cationic arrangement within the crystal lattice. This study successfully explained these alterations using magnetization and coercivity data and the probable cationic dispersion.

Immunohistochemical detection of 8-hydroxydeoxyguanosine: A biomarker of oxidative DNA damage in oral submucous fibrosis.

BACKGROUND: Oral submucous fibrosis (OSMF) is one of the common potentially malignant disorders prevailing in India. The primary etiological factors include tobacco and arecanut, which contain numerous reactive oxygen species (ROS). ROS attack guanine bases in DNA and form 8-hydroxydeoxyguanosine (8-OHdG), which can be detected in patients who have diseases associated with oxidative stress. The oxidative DNA damage produced by oxidative stress may induce malignant transformation. AIM: The aim of the present study is to detect the expression of 8-OHdG in OSMF patients and compare the expression within different grades of OSMF and also normal buccal mucosa. MATERIALS AND METHODS: A total of 30 samples were examined for the immunohistochemical expression of 8-OHdG. The control group included 10 formalin-fixed paraffin-embedded tissue blocks of the normal buccal mucosa. The study group includes 20 cases of formalin-fixed paraffin-embedded tissue blocks of OSMF (5 cases in each grade of very early, early, moderately advanced and advanced cases of OSMF). Three-micron thick tissue sections were made from each sample and stained with 8-OHdG antibody. The results were statistically analyzed using Kruskal-Wallis and Mann-Whitney U test. RESULTS: Statistically significant difference exists in the intensity of 8-OHdG expression between the study groups. The P-value obtained was <0.001, which was highly statistically significant. CONCLUSION: The present study is the first attempt to evaluate the expression of 8-OHdG in tissue samples of OSMF that revealed the role of free radicals and oxidative DNA damage in these patients. Further research with larger sample size, clinicopathologic correlation and long-term follow-up will shed more light on the pathogenesis of OSMF. It will also be useful for the development of new therapeutic strategies targeting treatment modalities for OSMF.

Effect of maize based composite flour noodles on functional, sensory, nutritional and storage quality.

To explore the feasibility of utilization of maize flour in noodle preparation, eight different combinations (T1 to T8) with varied amount of maize flour (MF), refined wheat flour (RWF), rice flour (RF), wheat gluten (WG), soya protein isolate (SPI), kansui (Sodium Carbonates), potato starch (PS) were extruded to standardize good quality noodles. Among various combinations tested, the combination T5 (50 %MF + 30 %RWF + 10 %SPI + 7 %RF + 3 %WG) was rated the best for appearance (8.3) colour (8.25) taste (8.5) elasticity (8.3) with an overall acceptability of 8.2 on a nine point hedonic rating sensory scale. There was no significant difference in normal noodle (NN) and Quality protein maize (QPM) noodle (QN) for T5 with respect to sensory characteristics when compared to control noodle (CN) prepared out of refined wheat flour. The cooked yield was more for maize based noodle (234 g NN and 220 g QN) with lower cooking loss of 7.80 and 7.76 respectively for NN & QN. The nutritional composition of maize noodles revealed that addition of 10 % soya protein isolate had increased the protein content of noodles to the tune of 16.6 and 12.7 % in QN and NN respectively. The soluble (3.18NN, 3.76QN) and insoluble fiber (21.67NN, 21.87QN) contents of both NN & QN was significantly more compared to CN (0.15 and 9.3 g).There was non- significant increase in moisture and peroxide values up to 3 months of storage with high overall acceptable sensory scores (4.0, 4.1, & 4.2 respectively for NN, QN and CN but beyond third month of storage the increase was significant. However the noodles were within the acceptable range up to 6 months of storage with an overall acceptability score of 3.0, 3.4 and 3.2 for NN, QN and CN respectively on a five point hedonic scale.

Oral pigmentation: A review.

Pigmentations are commonly found in the mouth. They represent in various clinical patterns that can range from just physiologic changes to oral manifestations of systemic diseases and malignancies. Color changes in the oral mucosa can be attributed to the deposition of either endogenous or exogenous pigments as a result of various mucosal diseases. The various pigmentations can be in the form of blue/purple vascular lesions, brown melanotic lesions, brown heme-associated lesions, gray/black pigmentations.

Multiple myeloma involving mandible: In an elderly female.

Multiple myeloma (MM) is a malignancy of plasma cell origin. It often has a multicentric origin within the bone. It makes about 1% of all malignancies and 15% of all hematologic malignancies. There is a monoclonal proliferation of abnormal plasma cells in this disease that arise from a single malignant precursor that has undergone uncontrolled mitotic division. These cells in turn produce one type of immunoglobulin light chain, either kappa or lambda. Unifocal, monoclonal proliferation of plasma cells is called plasmacytoma. Hereby, we present a case of a 65-year-old female patient who presented with a swelling of the mandible. The uniform sheets of plasma cells in the histopathology punched out radiolucencies in skull radiograph and the blood picture of anemia and hypercalcemia, confirmed the case as MM.

Langerhans cells in lichen planus and lichenoid mucositis an immunohistochemical study.

AIM: The aim of this study is to identify and evaluate Langerhans cell (LC) in lichen planus (LP), lichenoid mucositis (LM) and normal mucosa (NM) using CD1a monoclonal antibody immunohistochemically. MATERIALS AND METHODS: A total of 15 cases of oral lichen planus and 15 cases of LM were selected based on clinical examination and confirmed by histopathological analysis. The biopsies from the 10 patients were taken from normal buccal mucosa as control. Paraffin blocks of tissue were made, which are used for routine hematoxylin and eosin staining and immunohistochemical staining using biotin streptavidin methods (CD1a monoclonal antibody). Analysis of CD1a expression was performed by evaluating the labeling index (LI) for each slide. RESULTS: The mean CD1a LI for LP was significantly higher than that of LM and NM in the basal and supra basal layer. The mean CD1a positive cells in the connective tissues for LP were higher than that of LM and NM. CONCLUSION: This study clearly demonstrates a statistically significant increase in number of LC in LP than in LM, indicating the possible different immunopathogenic mechanisms.

Recurrent peripheral odontogenic fibroma associated with basal cell budding.

Peripheral odontogenic fibroma (POdF) is a rare benign odontogenic neoplasm. It represents the soft tissue counterpart of central odontogenic fibroma. The embryonic source of POdF has been suggested by many as arising from the rest of dental lamina that has persisted in the gingiva following its disintegration. It presents clinically as a firm, slow growing and sessile gingival mass, which is difficult to distinguish with more common inflammatory lesions. Very few cases of recurrence have been documented. It has been stated that histological budding of basal cell layer of the surface squamous epithelium is associated with higher recurrence and the presence of calcification in direct apposition to the epithelial rest is associated with lower recurrence. Hereby, we present a case which histologically exhibited budding of the basal cell layer, which could have been the reason for its recurrence.

Orthokeratinised odontogenic cyst mimicking periapical cyst.

Orthokeratinised odontogenic cyst (OOC) denotes the odontogenic cyst that microscopically has an orthokeratinised epithelial lining. OOC is characterised by a less-aggressive behaviour and a low rate of recurrence. This report describes a case of OOC involving posterior part of the mandible that mimicked periapical cyst in a 14-year-old boy. The initial clinical diagnosis was given as periapical cyst based on the clinical and radiographical features. Enucleation of the cyst was performed and the specimen was sent for histopathological examination. A definite diagnosis of OOC was made by histopathological examination of the biopsy specimen. This case emphases on including OOC in the differential diagnosis of radiolucencies occurring in the periapical region of non-vital tooth.

Malignant fibrous histiocytoma of the gingiva.

Malignant fibrous histiocytoma (MFH) is widely regarded as the commonest soft tissue sarcoma of adulthood which tends to occur in the deep soft tissues of the extremities and the retroperitoneum. Uncertain histogenesis and numerous subtypes make MFH a rather controversial entity. These tumours are relatively rare in the head and neck region accounting for only 1-3% of all cases of MFH. MFH exhibits a heterogenous histology of spindle cells in a characteristic storiform pattern with pleomorphic tumour cells and giant cells. A case is reported of an MFH of the gingiva in a 60-year-old woman who presented with a painful swelling originating from the left maxillary gingiva. The clinical, histopathological and immunohistochemical findings are discussed.

Maxillary second premolar with three roots and three separate root canals--case reports.

Aberrations in root canal systems are a commonly occurring phenomenon. Knowledge of the basic root canal anatomy and its variation is necessary for successful completion of endodontics. Maxillary second premolars usually have one root and one canal. The occurrence of these teeth having three roots and three canals is very rare. Three such cases of maxillary second premolar with three roots and three canals are presented here.

Comparative proteomics of the Mycobacterium leprae binding protein myelin P0: its implication in leprosy and other neurodegenerative diseases.

Mycobacterium leprae, the causative agent of leprosy invades Schwann cells of the peripheral nerves leading to nerve damage and disfigurement, which is the hallmark of the disease. Wet experiments have shown that M. leprae binds to a major peripheral nerve protein, the myelin P zero (P0). This protein is specific to peripheral nerve and may be important in the initial step of M. leprae binding and invasion of Schwann cells which is the feature of leprosy. Though the receptors on Schawann cells, cytokines, chemokines and antibodies to M. leprae have been identified the molecular mechanism of nerve damage and neurodegeneration is not clearly defined. Recently pathogen and host protein/nucleotide sequence similarities (molecular mimicry) have been implicated in neurodegenerative diseases. The approach of the present study is to utilise bioinformatic tools to understand leprosy nerve damage by carrying out sequence and structural similarity searches of myelin P0 with leproma and other genomic database. Since myelin P0 is unique to peripheral nerve, its sequence and structural similarities in other neuropathogens have also been noted. Comparison of myelin P0 with the M. leprae proteins revealed two characterised proteins, Ferrodoxin NADP reductase and a conserved membrane protein, which showed similarity to the query sequence. Comparison with the entire genomic database (www.ncbi.nlm.nih.gov) by basic local alignment search tool for proteins (BLASTP) and fold classification of structure-structure alignment of proteins (FSSP) searches revealed that myelin P0 had sequence/structural similarities to the poliovirus receptor, coxsackie-adenovirus receptor, anthrax protective antigen, diphtheria toxin, herpes simplex virus, HIV gag-1 peptide, and gp120 among others. These proteins are known to be associated directly or indirectly with neruodegeneration. Sequence and structural similarities to the immunoglobin regions of myelin P0 could have implications in host-pathogen interactions, as it has homophilic adhesive properties. Although these observed similarities are not highly significant in their percentage identity, they could be functionally important in molecular mimicry, receptor binding and cell signaling events involved in neurodegeneration.

Comparative proteomics of the Mycobacterium leprae binding protein myelin P0: its implication in leprosy and other neurodegenerative diseases

Mycobacterium leprae, the causative agent of leprosy invades Schwann cells of the peripheral nerves leading to nerve damage and disfigurement, which is the hallmark of the disease. Wet experiments have shown that M. leprae binds to a major peripheral nerve protein, the myelin P zero (P0). This protein is specific to peripheral nerve and may be important in the initial step of M. leprae binding and invasion of Schwann cells which is the feature of leprosy. Though the receptors on Schawann cells, cytokines, chemokines and antibodies to M. leprae have been identified the molecular mechanism of nerve damage and neurodegeneration is not clearly defined. Recently pathogen and host protein/nucleotide sequence similarities (molecular mimicry) have been implicated in neurodegenerative diseases. The approach of the present study is to utilise bioinformatic tools to understand leprosy nerve damage by carrying out sequence and structural similarity searches of myelin P0 with leproma and other genomic database. Since myelin P0 is unique to peripheral nerve, its sequence and structural similarities in other neuropathogens have also been noted. Comparison of myelin P0 with the M. leprae proteins revealed two characterised proteins, Ferrodoxin NADP reductase and a conserved membrane protein, which showed similarity to the query sequence. Comparison with the entire genomic database (www.ncbi.nlm.nih.gov) by basic local alignment search tool for proteins (BLASTP) and fold classification of structure-structure alignment of proteins (FSSP) searches revealed that myelin P0 had sequence/structural similarities to the poliovirus receptor, coxsackie-adenovirus receptor, anthrax protective antigen, diphtheria toxin, herpes simplex virus, HIV gag-1 peptide, and gp120 among others. These proteins are known to be associated directly or indirectly with neruodegeneration. Sequence and structural similarities to the immunoglobin regions of myelin P0 could have implications in host-pathogen interactions, as it has homophilic adhesive properties. Although these observed similarities are not highly significant in their percentage identity, they could be functionally important in molecular mimicry, receptor binding and cell signaling events involved in neurodegeneration.

L1210/B23.1 cells express equilibrative, inhibitor-sensitive nucleoside transport activity and lack two parental nucleoside transport activities.

Cultured mouse leukemia L1210 cells express the nucleoside-specific membrane transport processes designated es, ei, and cif. The es and ei processes are equilibrative, but may be distinguished by the high sensitivity of the former to 6-[(4-nitrobenzyl)thio]-9-beta-D-ribofuranosylpurine (NBMPR); the cif process is mediated by a Na+/nucleoside cotransporter of low sensitivity to NBMPR. Cells of an ei-deficient clonal line, L1210/MC5-1, were mutagenized, and clones were selected in soft agar medium that contained (i) NBMPR (an inhibitor of es processes), (ii) erythro-9-(2-hydorxy-3-nonyl)adenine (an inhibitor of adenosine deaminase), and (iii) arabinofuranosyladenine (a cytotoxic substrate for the three nucleotide transporters). The selection medium did not allow es activity and selected against cells that expressed the Na(+)-linked cif process. Cells of the L1210/B23.1 clonal isolate were deficient in cif transport activity, and inward fluxes of formycin B, a poorly metabolized analog of inosine, were virtually abolished by NBMPR in these cells. In the mutant cells, nonisotopic formycin B behaved as a countertransport substrate during influx of [3H]formycin B, and inward fluxes of the latter were competitively inhibited by purine and pyrimidine nucleosides. The transport behavior of L1210/B23.1 cells indicates that (i) the mutation/selection procedure impaired or deleted the Na(+)-linked cif process and (ii) es nucleoside transport activity is expressed in the mutant cells.

5'-S-(2-aminoethyl)-N6-(4-nitrobenzyl)-5'-thioadenosine (SAENTA), a novel ligand with high affinity for polypeptides associated with nucleoside transport. Partial purification of the nitrobenzylthioinosine-binding protein of pig erythrocytes by affinity chromatography.

Derivatives of N6-(4-aminobenzyl)adenosine (substituted at the aminobenzyl group) and 5'-linked derivatives of N6-(4-nitrobenzyl)adenosine (NBAdo) were evaluated as inhibitors of site-specific binding of [3H]nitrobenzylthioinosine (NBMPR) to pig erythrocyte membranes. Potent inhibitors were SAENTA [5'-S-(2-aminoethyl)-N6-(4-nitrobenzyl)-5'-thioadenosine] and acetyl-SAENTA (the 2-acetamidoethyl derivative of SAENTA). SAENTA was coupled to derivatized agarose-gel beads (Affi-Gel 10) to form an affinity matrix for chromatographic purification of NBMPR-binding polypeptides, which in pig erythrocytes are part of, or are associated with, the equilibrative nucleoside transporter. When pig erythrocyte membranes were solubilized with octyl glucoside (n-octyl beta-D-glucopyranoside) and applied to SAENTA-Affi-Gel 10 (SAENTA-AG10), polypeptides that migrated as a broad band on SDS/PAGE with an apparent molecular mass of 58-60 kDa were selectively retained by the affinity gel. These polypeptides were identified as components of the nucleoside transporter of pig erythrocytes by reactivity with a monoclonal antibody (mAb 11C4) that recognizes the NBMPR-binding protein of pig erythrocytes. Retention of the immunoreactive polypeptides by SAENTA-AG10 was blocked by NBAdo. The immunoreactive polypeptides were released from SAENTA-AG10 by elution under denaturing conditions with 1% SDS or by elution with detergent solutions containing competitive ligands (NBAdo or NBMPR). A 72-fold enrichment of the immunoreactive polypeptides was achieved by a single passage of solubilized, protein-depleted membranes through a column of SAENTA-AG10, followed by elution with detergent solutions containing NBAdo. These results demonstrate that polypeptide components of NBMPR-sensitive nucleoside-transport systems may be partly purified by affinity chromatography using gel media bearing SAENTA groups.

Identification of amino acid residues at the active site of human liver serine hydroxymethyltransferase.

Chemical modification of amino acid residues with phenylglyoxal, diethylpyrocarbonate, and N-bromosuccinimide indicated that at least one residue each of arginine, histidine, and tryptophan were necessary for the activity of human liver serine hydroxymethyltransferase. Protection by substrates suggested that these residues might occur at the active site of the enzyme.

Sodium-dependent nucleoside transport in mouse intestinal epithelial cells. Two transport systems with differing substrate specificities.

Nucleoside transport was examined in freshly isolated mouse intestinal epithelial cells. The uptake of formycin B, the C nucleoside analog of inosine, was concentrative and required extracellular sodium. The initial rate of sodium-dependent formycin B transport was saturable with a Km of 45 +/- 3 microM. The purine nucleosides adenosine, inosine, guanosine, and deoxyadenosine were all good inhibitors of sodium-dependent formycin B transport with 50% inhibition (IC50) observed at concentrations less than 30 microM. Of the pyrimidine nucleosides examined, only uridine (IC50, 41 +/- 9 microM) was a good inhibitor. Thymidine and cytidine were poor inhibitors with IC50 values greater than 300 microM. Direct measurements of [3H]thymidine transport revealed, however, that the uptake of this nucleoside was also mediated by a sodium-dependent mechanism. Thymidine transport was inhibited by low concentrations of cytidine, uridine, adenosine, and deoxyadenosine (IC50 values less than 25 microM), but not by formycin B, inosine, or guanosine (IC50 values greater than 600 microM). These data indicate that there are two sodium-dependent mechanisms for nucleoside transport in mouse intestinal epithelial cells, and that formycin B and thymidine may serve as model substrates to distinguish between these transporters. Neither of these sodium-dependent transport mechanisms was inhibited by nitrobenzylmercaptopurine riboside (10 microM), a potent inhibitor of one of the equilibrative (facilitated diffusion) nucleoside transporters found in many cells.