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Biomedical subjects

E Hibbert

Publications and source records attributed to E Hibbert.

6 recordsLinked to original sources
PubMed2000

Functional analysis of heterologous holin proteins in a lambdaDeltaS genetic background.

Holins are small hydrophobic proteins causing non-specific membrane lesions at the end of bacteriophage multiplication, to promote access of the murein hydrolase to their substrate. We have established a lambdaDeltaS genetic system, which enables functional expression of holins from various phages in an isogenic phage lambda background, and allows qualitative evaluation of their ability to support lysis of Escherichia coli cells. Synthesis of Holins is under control of native lambda transcription and translation initiation signals, and the temperature-sensitive CIts857 repressor. A number of different holins were tested in this study. The opposing action of phage lambda S105 and S107 holin variants in lysis timing could be confirmed, whereas we found evidence for a functionally non-homologous dual translational start motif in the Listeria phage Hol500 holin, i.e., the Hol500-96 polypeptide starting at Met-1 revealed a more distinct lytic activity as compared to the shorter product Hol500-93. The largest holin known, HolTW from a Staphylococcus aureus phage, revealed an early lysis phenotype in the lambdaDeltaSthf background, which conferred a plaque forming defect due to premature lysis. Mutant analysis revealed that an altered C-terminus and/or a V52L substitution were sufficient to delay lysis and enable plaque formation. These results suggest that the extensively charged HolTW C-terminus may be important in regulation of lysis timing. The gene 17.5 product of E. coli phage T7 was found to support sudden, saltatory cell lysis in the lambdaDeltaSthf background, which clearly confirms its holin character. In conclusion, lambdaDeltaSthf offers a useful genetic tool for studying the structure-function relationship of the extremely heterogeneous group of holin protein orthologs.

Amino Acid Sequence↗
PubMed2000

Clinical skills in early postgraduate medical trainees: patterns of acquisition of confidence and experience among junior doctors in a university teaching hospital.

BACKGROUND: Little is known about patterns of clinical skills acquisition among junior doctors undertaking clinical training in the early postgraduate period. A better understanding would assist in the design of effective educational interventions for this group. METHODS: We conducted a cross-sectional survey of the levels of confidence and experience with a broad raft of clinical skills among early PGY1 trainees (interns), PGY2s and PGY3s within a university teaching hospital network in Sydney at the beginning of the clinical year in 1999. The instrument was a new validated 69 item questionnaire. A total of 92 respondents took part, representing 100% of the PGY1 (n=36), PGY2 (n=31) and PGY3 (n=25) cohorts. RESULTS: Commencing interns reported high confidence levels with a small group of practical skills but less confidence with clinical management skills. Significant positive differences were found for confidence with all skill areas between early PGY1 and PGY3. We identified three patterns for skills acquisition. Pattern A was the most common, with a significant difference in levels of confidence and experience between PGY1 and PGY2 but not between PGY2 and PGY3 (e.g. suturing a simple laceration). In Pattern B, significant differences were found in levels of confidence and experience between PGY1 and PGY2 as well as between PGY2 and PGY3 (e.g. cardiopulmonary resuscitation). In Pattern C, significant differences were found in levels of experience between PGY2 and PGY3 but not between PGY1 and PGY2 (e.g. endotracheal intubation). There was a significant correlation between reported confidence and experience for all skill areas. CONCLUSIONS: Early postgraduate medical trainees in a Sydney teaching hospital acquire high levels of confidence and experience in most skill areas after two years of training. The first postgraduate year is particularly significant for the development of clinical skills.

Clinical Competence↗
PubMed1998

Metabolic and exercise endurance effects of coffee and caffeine ingestion.

Caffeine (Caf) ingestion increases plasma epinephrine (Epi) and exercise endurance; these results are frequently transferred to coffee (Cof) consumption. We examined the impact of ingestion of the same dose of Caf in Cof or in water. Nine healthy, fit, young adults performed five trials after ingesting (double blind) either a capsule (Caf or placebo) with water or Cof (decaffeinated Cof, decaffeinated with Caf added, or regular Cof). In all three Caf trials, the Caf dose was 4.45 mg/kg body wt and the volume of liquid was 7.15 ml/kg. After 1 h of rest, the subject ran at 85% of maximal O2 consumption until voluntary exhaustion (approximately 32 min in the placebo and decaffeinated Cof tests). In the three Caf trials, the plasma Caf and paraxanthine concentrations were very similar. After 1 h of rest, the plasma Epi was increased (P < 0.05) by Caf ingestion, but the increase was greater (P < 0.05) with Caf capsules than with Cof. During the exercise there were no differences in Epi among the three Caf trials, and the Epi values were all greater (P < 0.05) than in the other tests. Endurance was only increased (P < 0. 05) in the Caf capsule trial; there were no differences among the other four tests. One cannot extrapolate the effects of Caf to Cof; there must be a component(s) of Cof that moderates the actions of Caf.

Adult↗
PubMed1995

Giant double parathyroid adenoma presenting as a hypercalcaemic crisis.

The largest documented case of a double parathyroid adenoma is reported. The patient presented in hypercalcaemic crisis with a large intrathoracic mass. After removal of a massive cystic parathyroid adenoma from the right superior mediastinum, a second very large parathyroid adenoma was found on the contralateral side adjacent to the left thyroid lobe. This case illustrates the importance of the cervical approach, as well as routine bilateral neck exploration, for all cases of primary hyperparathyroidism.

Adenoma↗
PubMed1990

Case-control study of hyperpyrexia in children.

To test the association of hyperpyrexia (temperature greater than or equal to 41.1 degrees C) with increased rates of bacteremia and serious bacterial illness in young children, we performed a retrospective case-control study. Seventy-six hyperpyrexic children and an equal number of control cases with temperatures of 39.1-40 degrees C and 40.1-41.0 degrees C were identified. A significantly larger number of diagnostic procedures including blood cultures, urine cultures, chest x-rays and white blood cell counts were performed in the hyperpyrexic children (P less than 0.05). The frequency of serious bacterial infections and bacteremia did not differ among the groups (P greater than 0.05). Hyperpyrexic children need to be evaluated as thoroughly and carefully as any other febrile child but do not merit special consideration.

Bacterial Infections↗