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Biomedical subjects

E Davie

Publications and source records attributed to E Davie.

5 recordsLinked to original sources

Suppression of the abnormal phenotype of Salmonella typhimurium rfaH mutants by mutations in the gene for transcription termination factor Rho.

Mutations in the rfaH gene have previously been shown to cause premature termination of transcription of the traYZ operon of the F factor and also to prevent expression of the rfaGBIJ gene cluster of Salmonella typhimurium. In the present study, mutants were selected for their ability to restore the normal pattern of rfaGBIJ function. On the basis of this initial section, several classes of extragenic suppressor mutants were isolated that completely or partially corrected the Tra- and Rfa- phenotypes of the prototype rfaH mutant. The suppressor mutations included mutations in rho and mutations that mapped in or close to rpoBC. Other suppressor mutations were located elsewhere on the chromosome, presumably identifying other genes that play a role in the RfaH-mediated transcriptional regulation.

Gene Expression Regulation, Bacterial↗

Transcriptional organization of the rfaGBIJ locus of Salmonella typhimurium.

The transcriptional organization of the rfaGBIJ gene cluster of Salmonella typhimurium was studied by using lacZ and cat transcriptional probes. The results indicated that the leftward end of the gene cluster (rfaG-rfaB-rfaI) is an operon that is transcribed from one or more promoters that lie upstream of rfaG. The results further indicated that the product of the rfaH (sfrB) gene acts as a positive regulator of transcription of the entire rfaGBIJ cluster. At least one site required for the RfaH-mediated transcriptional regulation lies within or very close to the upstream promoter.

Chromosomes, Bacterial↗

Genetic basis of minicell formation in Escherichia coli K-12.

Hfr- and P1-mediated genetic transfer experiments failed to confirm the presence of a " minA " gene in Escherichia coli K-12, leading to the conclusion that mutation at a single locus, the minB locus, is sufficient to cause minicell production in this species.

Crosses, Genetic↗

The role of white cell count and C-reactive protein in the diagnosis of acute appendicitis.

BACKGROUND: Despite recent advances in diagnostic medicine, the diagnosis of appendicitis is still doubtful in a number of cases. Majority of the clinicians rely on their clinical examination strengthened by the laboratory tests. This study was carried out to find out the specificity and sensitivity of white cell count (WCC) and C-Reactive Protein (CRP) in diagnosing appendicitis in patients presenting with right iliac fossa pain. METHODS: A total of 259 patients were included in this study that presented in the hospital with acute right iliac fossa pain and later on operated and had appendicectomy. The histopathology data was collected to find out the frequency of negative appendicectomy. According to the histopathology reports these patients were grouped into three sub-groups as normal appendix, inflamed appendix or perforated/gangrenous appendix. A record was kept of the WCC and CRP levels of these patients on admission. RESULTS: A total of 259 patients were included in this study and out of them 37 had a normal appendix giving an over all negative appendicectomy rate of 14.3%. Out of these 11 were male and 26 were female, male to female ratio being 1:2.3. The age range was 12-73 with a median age of 24. Among the 222 patients who had appendicitis, 96 had a ruptured/perforated appendix and 126 had an inflamed appendix. Over all the WCC was elevated in 185 patients and CRP was elevated in 168 cases. The cut off value for white cell count was 11 x 10(6)/L. The C reactive protein levels were calculated by immunoturbidimetric test and the cut off value was taken as 1.7 mg/dl. The sensitivity and specificity of WCC in this study was 83% and 62.1% and that for CRP was 75.6% and 83.7 %. CONCLUSION: Both the inflammatory markers i.e. WCC and C-reactive protein can be helpful in the diagnosis, when measured together as this increases their positive predictive value.

Acute Disease↗