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Biomedical subjects

D S Gupta

Publications and source records attributed to D S Gupta.

At least 19 recordsLinked to original sources

The O18 antigens (lipopolysaccharides) of Escherichia coli. Structural characterization of the O18A, O18A1, O18B and O18B1-specific polysaccharides.

The O-specific polysaccharide moieties (PS) of the O18A, O18A1, O18B, and O18B1 antigens (lipopolysaccharides, LPS) consist of L-rhamnose (Rha), N-acetyl-D-glucosamine, D-galactose, and D-glucose in different molar ratios. By using chemical fragmentation, methylation, as well as one- and two-dimensional NMR spectroscopy, the structures of these polysaccharides were found to be [formula: see text] In O18A-PS and O18A1-PS x = 2, whereas in O18B-PS and in O18B11-PS x = 3. In all four polysaccharides alpha-D-Galp (residue D) is substituted at O-3. This substituent L (residue E) is beta-D-GlcpNAc-(1 in O18A-PS and O18A1-PS and it is alpha-D-Glcp-(1 in O18B-PS and O18B1-PS. Whereas there is no further substituent on the main chain of the O18A and O18B polysaccharides, in O18A1-PS and O18B1-PS the alpha-D-GlcpNAc residue A is substituted with alpha-Glcp-(1 (residue F), which is linked to O-6 in O18A1-PS and to O-4 in O18B1-PS. These results show that the O18 antigen comprises a group of four related LPS (O18A and O18B, with their glucosylated forms O18A1 and O18B1). The results are discussed with respect to epitope definition and biochemical implications.

Carbohydrate Conformation

Structures of the O1B and O1C lipopolysaccharide antigens of Escherichia coli.

The O-specific moieties of the O1B antigen (lipopolysaccharide) from Escherichia coli O1B:K1 and the O1C antigen from E. coli O1C:K- both consist of L-rhamnose, D-galactose, N-acetyl-D-glucosamine, and N-acetyl-D-mannosamine in a molar ratio of 2:1:1:1. By using fragmentation procedures, methylation analysis, and one- and two-dimensional nuclear magnetic resonance spectroscopy, the structures of these polysaccharides were found to be [formula: see text] In the O1B polysaccharide X is 2, and in the O1C polysaccharide X is 3. With the recently published structure of the O1A polysaccharides (B. Jann, A. S. Shashkov, D. S. Gupta, S. M. Panasenko, and K. Jann, Carbohydr. Polym. 18:51-57 1992), three related O1 antigens are now known. Their common (O1-specific) epitope is suggested to be the side-chain N-acetyl-D-mannosamine residue.

Carbohydrate Sequence

Odontoameloblastoma.

A case of odontoameloblastoma affecting the left mandible is reported. Initially treated by conservative excision due to its small size, the lesion recurred after 18 months and was treated by radical excision and subsequent reconstruction by a rib graft.

Ameloblastoma

Osteomyelitis of the mandible in marble bone disease.

Marble bone disease is a rare skeletal disorder. Osteomyelitic changes in the jaw bones are frequently seen in this disease. Considering the rarity of the disease, a case of osteomyelitis of the mandible in marble bone disease is presented, together with a review of the available literature.

Child

Mandibular osteomyelitis caused by Actinomyces Israelii. Report of a case.

An unusual case of cervicofacial actinomycosis with cortical osteomyelitis of the ascending ramus is presented. The portal of entry of the infection was most probably by an extra oral route. The authors have emphasized the importance of repeated smear examinations, cultures, and sensitivity tests to rule out actinomycosis in such cervicofacial infections. The difficulties encountered in the isolation of A. Israelii are discussed.

Actinomyces

Pan-mandibular keratocyst with eosinophilia.

A case of pan-mandibular keratocyst with eosinophilia is presented. The authors have not so far in the literature come across such an extensive cystic lesion involving complete mandible and showing no preponderant signs or symptoms.

Eosinophilia

Estimation of major immunoglobulin profile in oral submucous fibrosis by radial immunodiffusion.

Oral submucous fibrosis is defined as a collagen disease. The major immunoglobulin profile of 10 patients of oral submucous fibrosis (OSF) is estimated by radial immunodiffusion technique. The possible existence of autoimmune phenomena is expressed. It was observed in the present study that the severity of oral submucous fibrosis was directly proportional to the estimated elevated levels of major immunoglobulins. This may be taken as an indicator to know the gravity of this oral condition and also to evaluate the various related gammopathies and their possible management. It is anticipated that the knowledge of the immunoprofile would open new avenues for exploration of the condition from a new dimension.

Adult

Escherichia coli O18ac antigen: structure of the O-specific polysaccharide moiety.

The O-specific polysaccharide moiety (O18ac polysaccharide) of the O18ac antigen (lipopolysaccharide) from Escherichia coli 2980 (O18ac:K5:Fim+:H-) was isolated in pure form by degradation of the lipopolysaccharide and chromatography on Sephadex G-50. The primary structure of the O18ac polysaccharide was elucidated by composition, fragmentation procedures, methylation analysis, and nuclear magnetic resonance spectroscopy. The polysaccharide consists of repeating units of the pentasaccharide: (formula; see text) which are joined in the polymer by alpha-1,2 linkages.

Antigens, Bacterial