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S Dheer

Publications and source records attributed to S Dheer.

11 recordsLinked to original sources
PubMed2002

Radiographically diagnosed antral gastritis: findings in patients with and without Helicobacter pylori infection.

The purpose of this study was to characterize the radiographic findings of antral gastritis and to determine whether there are differences in the appearance of antral gastritis in patients with and without Helicobacter pylori infection. A search of radiology, endoscopy and pathology files revealed 90 patients with antral gastritis on double contrast upper gastrointestinal tract studies who had endoscopy with testing for H. pylori. The barium studies were evaluated to further characterize the findings of antral gastritis without knowledge of the H. pylori status of the patients or of the endoscopy or pathology findings. The radiographic findings of antral gastritis included thickened folds in 67 patients (74%), polypoid antral gastritis (a subset of patients with thickened folds) in 6 (9%), antral erosions in 21 (23%), enlarged areae gastricae in 14 (16%), crenulation of the lesser curvature in 4 (4%), mucosal nodularity in 2 (2%), a hypertrophied antral-pyloric fold in 2 (2%) and antral striae in 1 (1%). 43 patients (48%) with antral gastritis were H. pylori positive and 47 patients (52%) were H. pylori negative. Thickened folds were detected in 39 H. pylori-positive patients (91%) with antral gastritis vs 28 H. pylori-negative patients (60%) (p<0.001); polypoid gastritis in 6 H. pylori-positive patients (14%) vs 0 H. pylori-negative patients (p<0.05); enlarged areae gastricae in 14 H. pylori-positive patients (33%) vs 0 H. pylori-negative patients (p<0.0001); and antral erosions in 2 H. pylori-positive patients (5%) vs 19 H. pylori-negative patients (40%) (p<0.0001). Our experience suggests that antral gastritis caused by H. pylori infection is associated with characteristic features on double contrast studies (including thickened folds, polypoid gastritis and enlarged areae gastricae) and that this condition is rarely associated with antral erosions. Thus, radiologists can often suggest whether the patient's gastritis is caused by H. pylori on the basis of radiographic findings.

Adult↗
PubMed2001

Orbital varix.

Explore the source record for details and available documents.

Adult↗
PubMed1996

Redundant homosexual F transfer facilitates selection-induced reversion of plasmid mutations.

F plasmids use surface exclusion to prevent the redundant entry of additional F plasmids during active growth of the host cells. This mechanism is relaxed during stationary phase and nonlethal selections, allowing homosexual redundant plasmid transfer. Homosexual redundant transfer occurs in stationary-phase liquid cultures, within nongrowing populations on solid media, and on media lacking a carbon source. We examined the relationship between homosexual redundant transfer, which occurs between F+ hosts, and reversion of a plasmid-encoded lac mutant allele, lacI33omegalacZ. Sodium dodecyl sulfate (SDS) and mutations that prevent normal transfer to F- cells reduced redundant transfer and selection-induced reversion of the lacI33omegalacZ allele. A recA null mutation reduced redundant transfer and selection-induced reversion of the lacI33omegalacZ mutation. Conversely, a recD null mutation increased redundant transfer and selection-induced reversion of the lacI33omegalacZ allele. These results suggest an explanation for why SDS and these mutations affect reversion of the plasmid lacI33omegalacZ allele. However, a direct causal relationship between transfer and reversion remains to be established. These results suggest that Rec proteins play an active role in redundant transfer and/or that redundant transfer is regulated with the activation of recombination. Redundant homosexual plasmid transfer during a period of stress may represent a genetic response that facilitates evolution of plasmid-encoded functions through mutation, recombination, reassortment, and dissemination of genetic elements present in the populations.

Alleles↗
PubMed1994

Isolation and characterization of adenovirus-associated VA RNAs of human adenovirus type 7.

Two genes for virus-associated VA RNAs in the human adenovirus type 7 (Ad7) genome are compared to Ad2, Ad4, Ad5, simian VA RNAs, and pol III transcripts of Epstein-Barr virus. The newly identified VA RNA-encoding genes of Ad7 contain two relatively conserved intragenic promoter (elements A and B), the double-stranded RNA-dependent protein kinase (PK) active site-binding domain and transcriptional terminators. The conserved features extend to the VA RNA genes of simian and avian origin.

Adenoviruses, Human↗
PubMed1990

Adenovirus vaccine vectors expressing hepatitis B surface antigen: importance of regulatory elements in the adenovirus major late intron.

Adenovirus types 4 and 7 are currently used as live oral vaccines for prevention of acute respiratory disease caused by these adenovirus serotypes. To investigate the concept of producing live recombinant vaccines using these serotypes, adenovirus types 4 (Ad4) and 7 (Ad7) were constructed that produce HBsAg upon infection of cell cultures. Ad4 recombinants were constructed that express HBsAg from a cassette inserted 135 bp from the right-hand terminus of the viral genome. The cassette contained the Ad4 major late promoter followed by leader 1 of the tripartite leader, the first intervening sequence between leaders 1 and 2, leaders 2 and 3, the HBsAg gene, and tandem polyadenylation signals from the Ad4 E3B and hexon genes. Using this same cassette, a series of Ad4 recombinants expressing HBsAg were constructed with deletions in the intervening sequence between leaders 1 and 2 to evaluate the contribution of the downstream control elements more precisely. Inclusion of regions located between +82 and +148 as well as +148 and +232 resulted in increases in expression levels of HBsAg in A549-infected cells by 22-fold and 44-fold, respectively, over the levels attained by an adenovirus recombinant retaining only sequences from +1 to +82, showing the importance of these elements in the activation of the major late promoter during the course of a natural Ad4 viral infection. Parallel increases were also observed in steady-state levels of cytoplasmic HBsAg-specific mRNA. When similar Ad7 recombinant viruses were constructed, these viruses also expressed 20-fold more HBsAg due to the presence of the intron. All Ad4 and Ad7 recombinants produced HBsAg particles containing gp27 and p24 which were secreted in the medium. When dogs were immunized intratracheally with one of these Ad7 recombinants, they seroconverted to both Ad7 and HBsAg to a high level.

Adenoviruses, Human↗
PubMed1988

Construction and expression of hybrid plasminogen activators prepared from tissue-type plasminogen activator and urokinase-type plasminogen activator genes.

Recent data from several studies have suggested that the non-protease domains in tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA) determine their biological specificities, including binding to fibrin clots and survival in the circulatory system (Van Zonneveld, A.-J., Veerman, H., and Pannekoek, H. (1986) Proc. Natl. Acad. Sci. U. S. A. 83, 4670-4674; Rijken, D. C., and Emeis, J. J. (1986) Biochem. J. 238, 643-646). Structural manipulations (e.g. deletions, additions, or substitutions) in these domains can thus be utilized to maximize the desired biological effects. Using recombinant DNA technology, we constructed a number of hybrid molecules from the t-PA and u-PA genes. In hybrid A, the epidermal growth factor and finger domains of t-PA (residues 1-91) were replaced by the epidermal growth factor and kringle of u-PA (residues 1-131). In hybrids B and C, the u-PA kringle (residues 50-131) was inserted either before (residue 92) or after (residue 261) the double-kringle region of t-PA. All these hybrid PAs containing three kringles were expressed in mouse fibroblast cells (C-127). The hybrid proteins were synthesized in predominantly a single-chain form with molecular weights of 70,000-80,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and were enzymatically active as assayed by the fibrin-agar plate method. In vitro studies on the binding of hybrid PAs to fibrin showed that hybrid B, like t-PA, possesses affinity toward fibrin, while hybrid A shows lower binding. This suggests that the finger domain, which is not present in hybrid A, plays a role in conferring fibrin affinity to the hybrid PAs. The enzymatic activities of the hybrids were compared with that of recombinant t-PA (rt-PA) expressed in the same vector/host system and found to be similar in activity toward a chromogenic peptide substrate. In addition, plasminogen activation with all the hybrid-PAs, as with rt-PA, was stimulated by fibrin, with the order of activity being rt-PA greater than or equal to hybrid B greater than hybrid C greater than hybrid A. This study shows the feasibility of shuffling functional domain(s) of known specificity in plasminogen activators which may lead to the design of a superior thrombolytic agent.

Cell Line↗