Search PubMed⌕ Search

Biomedical subjects

T Lewis

Publications and source records attributed to T Lewis.

117 records · Page 7Linked to original sources
PubMedDate not supplied

Suppressors of a spo0A missense mutation and their effects on sporulation in Bacillus subtilis.

The spo0A gene product of Bacillus subtilis is a transcriptional regulator that is required for the initiation of sporulation. It has not been possible to isolate mutations that suppress the sporulation defect caused by spo0A null mutations. We describe the isolation and characterization of mutations that suppress the severe sporulation defect caused by a spo0A missense mutation (spo0A9V). Two suppressor mutations, spa2 and spa4, have been characterized in combination with, and separated from, the spo0A9V mutation. Both were located in the carboxyl half of Spo0A, in the putative DNA binding, transcriptional activation region. spa2 was in codon 174, causing a leucine to arginine change (spo0A174LR), and spa4 was in codon 162 (of 267), causing a histidine to arginine change (spo0A162HR). spa2 and spa4 significantly restored sporulation to the spo0A9V mutant, however, the appearance of heat resistant spores was delayed relative to wild-type. When separated from spo0A9V, that is, as single mutations in spo0A, spa4 caused a delay in sporulation, while spa2 allowed apparently normal sporulation. The spa mutations caused interesting phenotypes when combined with other early sporulation mutations. spa2 suppressed the sporulation defect caused by spo0E11. This was most easily seen in spo0E11 abrB double mutants, which had a much more severe sporulation defect than the spo0E11 single mutant. That is, spo0E11 and abrB mutations caused a synthetic (synergistic) sporulation phenotype. Both the spa2 spo0A9V and the spa4 spo0A9V alleles greatly enhanced the sporulation defect caused by mutations in spoIIJ, spo0J and spo0K. The significance of these synthetic sporulation defects is discussed.

Bacillus subtilis↗
PubMedDate not supplied

Bromocriptine in the treatment of post-polio fatigue: a pilot study with implications for the pathophysiology of fatigue.

Fatigue is the most commonly reported and most disabling of all post-polio sequelae (PPS). Bromocriptine mesylate (Parlodel) was employed in a placebo-controlled trial in five survivors of paralytic polio who continued to report moderate to severe daily fatigue after complying with the conservative treatments prescribed for PPS. Placebo was given for 4 wk followed by increasing doses of bromocriptine mesylate, administered at 12:00 pm for 28 days, which reached a total dose of 12.5 mg/day. Three subjects reported marked symptom improvement on bromocriptine but not on placebo. Their reported difficulty with attention, concentration, word finding, mind wandering, memory, thinking clearly, and fatigue on awakening was significantly negatively correlated with days on bromocriptine but not with days on placebo. Before the drug trial began, responders had clinically impaired performance on neuropsychologic tests of attention and information processing speed, more than twice as many hyperintensities on magnetic resonance imaging of the brain, abnormally low fasting adrenocorticotropic hormone levels, and nearly double the mean plasma prolactin level compared with nonresponders. The implications of these findings for the pathophysiology of fatigue are discussed. A double-blind, placebo-controlled, multicenter study will be needed to confirm bromocriptine's efficacy in treating attentionally and neurophysiologically impaired polio survivors whose severe and disabling fatigue does not respond to conservative therapies.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Comparing no-touch and tympanic thermometer temperature recordings.

Temperature is a vital sign which can be measured using various types of clinical thermometers. Pulmonary artery temperature is considered the 'gold standard', but this measurement is not usually clinically practical. There is currently no consensus for optimal alternative site or equipment. This research compares 178 simultaneous measurements from 5 clinical areas, using two types of thermometers: tympanic and no-touch temporal. No-touch thermometers were all set to oral equivalent. Tympanic thermometers were adjusted to either oral (n=105) or core (n=73) equivalent. Maximum acceptable difference was identified as 1oC. Two data sets (oral/core; oral/oral) were analysed using Bland-Altman method on Excel programmes, comparing all thermometers and separating oral and core-equivalent tympanics. The two thermometers were found not to be equivalent. As a simple comparison between two thermometers, this research cannot identify which thermometer is more accurate.

Bias↗
PubMedDate not supplied

Improving tracheostomy care for ward patients.

The number of patients with a tracheostomy being cared for in the ward setting has increased recently as intensive care clinicians use this procedure to aid early weaning from mechanical ventilation. As a result, ward staff are providing the specialist care required by patients with a tracheostomy more frequently. This article describes how the outreach team and the critical care practice development nurse in one trust collaborated to identify, develop and implement strategies to ensure that patients with a tracheostomy in the ward setting would be cared for by an educated and supported team of nurses.

Audiovisual Aids↗