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Biomedical subjects

G Coleman

Publications and source records attributed to G Coleman.

At least 37 records · Page 2Linked to original sources
PubMed1995

Nucleotide sequence of the Staphylococcus aureus RNA polymerase rpoB gene and comparison of its predicted amino acid sequence with those of other bacteria.

The complete nucleotide sequence of the rpoB gene which encodes the beta subunit of S. aureus RNA polymerase has been determined. The RpoB protein, consists of 1182 amino acids and has a novel initiation codon UUG which initiates protein synthesis with methionine. There is a very strong Shine-Dalgarno complementarity and the -10 and -35 promoter hexameric sequences are TAATAT and CCGTTT, respectively. A rho-dependent termination site, CAATCAA, is present which overlaps the -35 promoter sequence of the adjacent rpoC gene a feature which may have a role in the co-ordinate expression of the two genes. A strong homology and conserved regions were found to exist over the predicted amino acid sequences coding for S. aureus rpoB and the equivalent proteins in Escherichia coli, Pseudomonas putida, Salmonella typhimurium, Chlamydia trachomatis, cyanobacterium Anabaena sp. strain PCC 7120.

Amino Acid Sequence↗
PubMed1995

Nucleotide and deduced amino acid sequence of the gene for a novel protein with a possible regulatory function encoded in the beta operon of Staphylococcus aureus.

Although considerable homology exists between the translation products of the rplL, rpoB and rpoC genes of the beta operons of the Gram-negative organism Escherichia coli and the Gram-positive Staphylococcus aureus the region between the rplL and rpoB genes is quite different in the two bacterial species. In E. coli the 324 bp has three centres of dyad symmetry in the first half of the sequence and multiple nonsense codons in all three reading frames. By contrast, the corresponding region in S. aureus consists of 1000 bp capable of forming a similar arrangement of stem-loop structures but with an open reading frame, sited 177 bp downstream of the end of rplL and 217 bp upstream of the beginning of the rpoB gene, with consensus initiation and termination signals, which if translated would generate a 22,665 Da protein with 202 amino acids. In view of the inability to find any significant homology with other proteins in the data bank and because the evidence suggests, as in E. coli, that the rplL-rpoB intergenic sequence is involved in regulation it is proposed that the expression product of orf202 may be a further element of control in the S. aureus beta operon.

Amino Acid Sequence↗
PubMed1994

Bladder autoaugmentation by vesicomyotomy in the pediatric neurogenic bladder.

OBJECTIVES: The authors describe the procedure of bladder autoaugmentation by vesicomyotomy in 12 pediatric patients with neurogenic bladders. METHODS: Indications for augmentation included low-capacity, high-pressure bladders with incontinence despite maximal anticholinergic therapy. Clean intermittent catheterization was successfully reinstituted postoperatively and no patient has subsequently required enterocystoplasty. RESULTS: There were no major complications and eight patients underwent concurrent procedures on the bladder. Urodynamic studies revealed a mean increase in capacity of 40% and a mean decrease in leak point pressure of 33% compared with preoperative values. CONCLUSIONS: Early clinical experience would suggest that vesicomyectomy (excision of released detrusor) offers no advantages over vesicomyotomy in pediatric patients. Vesicomyotomy (simple incision into detrusor) proved to be a simple technique that could be safely performed in pediatric patients.

Adolescent↗
PubMed1994

Sleepiness after glucose in narcolepsy.

The issue of whether a high carbohydrate intake affects sleepiness and sleep variables has been studied in normals but not in patients suffering from narcolepsy, despite anecdotal evidence that sugars may facilitate sleepiness in this population. This study investigated whether the intake of 50 g glucose exacerbated sleepiness in narcolepsy subjects. A double-blind cross-over study, involving 12 narcolepsy subjects and 12 matched controls, measured behaviour after a light lunch supplemented with a drink of either 50 g glucose or placebo (artificially sweetened drink). The main dependent variables were the performance and EEG measures from the Wilkinson Auditory Vigilance Task (WAVT) and sleep variables from a 45 minute nap. The results indicate that in the narcolepsy subjects glucose was associated with decreased wake duration, reduced sleep onset latency and more spontaneous and induced sleep stage changes during the WAVT, while the nap revealed an increased intensity of sleepiness after glucose as measured by the Polygraphic Score of Sleepiness. Eleven of the twelve narcolepsy subjects showed increased REM duration in the nap after glucose. The findings are discussed in relation to serotonin synthesis, basal sleepiness and possible irregularities in the action of insulin.

Journal Article↗
PubMed1993

Molecular cloning and nucleotide sequence analysis of the maltose-inducible porin gene of Aeromonas salmonicida.

The gene for the Aeromonas salmonicida maltose-inducible porin (maltoporin) was cloned into phagemid pTZ18R in two restriction fragments, 0.6-kb PstI/KpnI and 1.7-kb SphI, of genomic DNA and their nucleotide sequences were determined. Open reading frames of 1329 and 1335 bp translated into sequences of 443 and 445 amino acids, with a 23 or 25 amino acid signal sequence and a 420 amino acid mature protein of molecular mass 46424 Da. Putative ribosome binding sites, AGGA and GGGAA, occurred 9 bp upstream of two possible ATG initiation codons. The A. salmonicida gene product showed a high degree of similarity with Escherichia coli LamB, and codon usage was very similar to that of another A. salmonicida outer membrane protein but markedly different from those of extracellular proteins.

Aeromonas↗
PubMed1993

A comparison of the amino acid sequence of the serine protease of the fish pathogen Aeromonas salmonicida subsp. salmonicida with those of other subtilisin-type enzymes relative to their substrate-binding sites.

The amino acid sequence of the so-called 70 kDa (actually 64 kDa) serine protease secreted by the Gram-negative fish pathogen Aeromonas salmonicida has been determined. It shows a high degree of homology with the complete sequence of other bacterial serine proteases which, with molecular masses of approximately 30 kDa, are less than half its size. This homology is particularly marked in regions adjacent to the catalytic triad Asp32, His64 and Ser221 of subtilisin BPN'. Significant features of the A. salmonicida enzyme, a new member of the group of cysteine-containing subtilisin-type serine proteases, are the presence of six cysteine residues in the mature enzyme, a 37 amino acid extension at the N-terminus and 215 amino acids at the C-terminus when compared with subtilisin BPN'. In addition to a number of smaller peptide insertions there is a non-aligned 32 amino acid sequence in a position corresponding to its introduction between Lys213 and Tyr214 of subtilisin BPN'. This sequence is highly hydrophilic, with Asp/Asn accounting for 10 of the 32 amino acids. Further, the possession of two Cys residues separated by 24 amino acids provides the capacity for stabilizing the peptide as an externalized loop.

Aeromonas↗
PubMed1993

Essential fatty acids in the treatment of premenstrual syndrome.

OBJECTIVE: To determine whether essential fatty acids are effective in the treatment of premenstrual syndrome (PMS). METHODS: In a randomized, double-blind, crossover trial, we studied 27 women diagnosed with PMS over ten menstrual cycles and 22 symptom-free controls over one cycle. The first cycle was used for diagnostic assessment. For the women with PMS, placebos were administered during the second cycle. This was followed by randomization to four cycles of active treatment with essential fatty acids and four cycles of placebo, with a crossover after completion of the fourth cycle. Assessment of symptoms and diagnosis of PMS were based on daily self-ratings made by the women throughout the study. RESULTS: Treatment with essential fatty acids did not reduce premenstrual symptoms or symptom cyclicity. However, time had a significant effect on a number of symptoms, indicating either a placebo effect or an effect from participation in the study. Women with PMS had a significantly higher frequency of dysmenorrhea and familial PMS than did the symptom-free controls. CONCLUSION: Treatment with essential fatty acids is ineffective therapy for PMS. The improvement we observed over time can be ascribed to either a placebo effect or participation in the study.

Adult↗
PubMed1992

The cloning and nucleotide sequence of the serine protease gene (aspA) of Aeromonas salmonicida ssp. salmonicida.

The gene for Aeromonas salmonicida serine protease has been cloned into phagemid pTZ18R in two restriction fragments, 2.0-kb PstI and 2.3-kb KpnI, of genomic DNA. The nucleotide sequences of the two fragments have been determined, in both directions, after subcloning, by double-stranded sequencing of nested deletions. An open reading frame of 1863 bp translated into a sequence of 621 amino acids, a 24-amino acid signal peptide and a 597-amino acid mature enzyme of molecular mass 64,173 Da. The consensus sequence, NGTS, of a serine protease substrate primary binding site was identified and a putative ribosome-binding site GGAG occurred 6 bp upstream of the ATG initiation codon.

Aeromonas↗
PubMed1992

Cloning and physical mapping of the Staphylococcus aureus rplL, rpoB and rpoC genes, encoding ribosomal protein L7/L12 and RNA polymerase subunits beta and beta'.

Using segments of the Escherichia coli rpoB and rpoC genes as heterologous probes, we have identified and cloned an 8.3 kb PstI fragment from the Staphylococcus aureus genome containing the rpoB and rpoC genes, which respectively encode the beta and beta' subunits of DNA-directed RNA polymerase. This region is almost certainly equivalent to the rif locus, located near to fus at interval 12/13 on the S. aureus linkage map. Limited DNA sequencing revealed the gene order rpoB-rpoC (transcribed from left to right) and identified the rplL gene, encoding ribosomal protein L7/L12, upstream of rpoB. This and other evidence suggests that the rpoBC genes of S. aureus form part of a large gene cluster encoding components of the transcription and translation apparatus which is well-conserved in other eubacteria.

Amino Acid Sequence↗
PubMed1991

Implications of placebo theory for clinical research and practice in pain management.

We review three possible theoretical mechanisms for the placebo effect: conditioning, expectancy and endogenous opiates and consider the implications of the first two for clinical research and practice in the area of pain management. Methodological issues in the use of placebos as controls are discussed and include subtractive versus additive expectancy effects, no treatment controls, active placebo controls, the balanced placebo design, between- versus within-group designs, triple blind methodology and the double expectancy design. Therapeutically, the possibility of shaping negative placebo responses through placebo sag, overservicing and the use of placebos on their own are explored. Suggestions for using conditioned placebos strategically in conjunction with nonplacebos are made and ways of maximizing the placebo component of nonplacebo treatments are examined. Finally, the importance of investigating the placebo effect in its own right is advocated in order to better understand the long-neglected psychological aspects of the therapeutic transaction.

Chronic Disease↗
PubMed1990

The patterns of extracellular protein formation by spontaneously-occurring rifampicin-resistant mutants of Staphylococcus aureus.

Spontaneously-occurring rifampicin-resistant mutants of Staphylococcus aureus were isolated on 4% (w/v) Tryptone Soya Agar containing 4 and 40 times the m.i.c. for rifampicin. A number of colonies were selected at each rifampicin concentration and were grown aerobically in 3% (w/v) Tryptone Soya Broth for 24 h at 37 degrees C. In the case of S. aureus RN4220 all the mutants grew to bacterial densities up to approximately 1.7 times more than the parent organism. The corresponding levels of extracellular protein secretion varied over a 5-fold range, all the mutants being less productive than the parent. By contrast, mutants of the wild-type Wood 46 strain achieved bacterial densities of only 45-83% that of the parent whilst exoprotein secretion showed a smaller 1.7-fold variation. However, widely-differing patterns of exoproteins were revealed by SDS-polyacrylamide gel electrophoresis of the parent and mutant organisms of both strains.

Bacterial Proteins↗
PubMed1990

Malleus head fixation: association with pseudohypoparathyroidism.

Pseudohypoparathyroidism (PHP) is a heterogenous syndrome resulting from bone and renal resistance to parathyroid hormone (PTH). Hypocalcemia and hyperphosphatemia occur despite elevated PTH levels. Head and neck manifestations of PHP include tetany, laryngeal spasm, and ectopic calcification in the eye, dentition, subcutaneous tissue and brain. The first case of malleus head fixation caused by ectopic calcification in a PHP patient is reported. Normalization of serum calcium and phosphate levels does not appear to retard or correct this abnormality. Ossiculoplasty or amplification is currently the recommended treatment in PHP patients with malleus head fixation.

Adult↗
PubMed1989

The effect of glucose on the expression of extracellular protein genes by Staphylococcus aureus strain V8.

The bacteria from overnight cultures (20 h) of S. aureus V8 and exp negative mutant K6812-1, grown, aerobically, in 3% (w/v) Tryptone Soya Broth, at 37 degrees C, were resuspended in fresh medium, in the case of the parent strain +/- 1% (w/v) glucose, without change in bacterial density. During a 6 h incubation period there was an approximate doubling of bacterial density, to the same level, in each case. However, exoprotein production by the mutant was only 20% that of the parent whilst the addition of glucose to the V8 strain resulted in a tenfold reduction in the exoprotein formed. SDS-polyacrylamide gel electrophoresis showed that the exoprotein patterns of both organisms after 6 h incubation were the same as those observed in the overnight cultures whilst the presence of 1% (w/v) extra glucose changed the pattern produced by the parent to one similar to that of the mutant. The results showed that conditions which lead to the rapid formation of glucose catabolites produced an effect consistent with the inhibition of the activity of the exp gene product.

Bacterial Proteins↗