New method to evaluate the practice of positive pressure ventilation in intensive care units.
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Critical Care↗
Biomedical subjects
M Rothwell
Publications and source records attributed to M Rothwell.
Association of hypertension with T594M mutation in beta subunit of epithelial sodium channels in black people resident in London.
BACKGROUND: Liddle's syndrome is a rare inherited form of hypertension in which mutations of the epithelial sodium channel result in increased renal sodium reabsorption. Essential hypertension in black patients also shows clinical features of sodium retention so we screened black people for the T594M mutation, the most commonly identified sodium-channel mutation. METHODS: In a case-control study, 206 hypertensive (mean age 48.0 [SD 11.8] years, men:women 80:126) and 142 normotensive (48.7 [7.4] years; 61:81) black people who lived in London, UK, were screened for T594M. Part of the last exon of the epithelial sodium-channel beta subunit from genomic DNA was amplified by PCR. The T594M variant was detected by single-strand conformational polymorphism analysis of PCR products and confirmed by DNA sequencing. FINDINGS: 17 (8.3%) of 206 hypertensive participants compared with three (2.1%) of 142 normotensive participants possessed the T594M variant (odds ratio [OR]=4.17 [95% CI 1.12-18.25], p=0.029). A high proportion of participants with the T594M variant were women (15 of 17 hypertensive participants and all three normotensive participants), whereas women comprised a lower proportion of the individuals screened (61.2% hypertensive, 57.7% normotensive). However, the association between the T594M variant and hypertension persisted after adjustment for sex and body-mass index (Mantel-Haenszel OR=5.52 [1.40-30.61], p=0.012). Plasma renin activity was significantly lower in 13 hypertensive participants with the T594M variant (median=0.19 ng mL(-1) h(-1)) than in 39 untreated hypertensive individuals without the variant (median=0.45 ng mL(-1) h(-1), p=0.009). INTERPRETATION: Among black London people the T594M sodium-channel beta subunit mutation occurs more frequently in people with hypertension than those without. The T594M variant may increase sodium-channel activity and could raise blood pressure in affected people by increasing renal tubular sodium reabsorption. These findings suggest that the T594M mutation could be the most common secondary cause of essential hypertension in black people identified to date.
Black People↗
The uptake and release of fluoride by ion-leaching cements after exposure to toothpaste.
OBJECTIVES: The cariostatic action associated with the glass-ionomer cement (GIC) is usually attributed to its sustained release of fluoride. However the ability of the GIC to act as a fluoride reservoir, taking it up from an external source (e.g. toothpaste, mouthwash) and subsequently releasing it over time, may also be a contributory factor. This study investigated the reservoir effect of various recently introduced ion-releasing cements: two resin-modified glass-ionomer cements (Fuji II LC, Vitremer), a compomer (acid-modified composite resin) (Dyract), and a recently introduced conventional glass-ionomer (Fuji IX). METHODS: Specimens were exposed to a fluoridated toothpaste after 28 and/or 58 days. The release of fluoride into the storage water, both before and after exposure, was monitored using a differential electrode cell. RESULTS: There was no significant difference in the fluoride releases from Vitremer and Fuji II LC. These materials released significantly more fluoride than Fuji IX and Dyract. All the materials released more fluoride on the day after exposure to an external fluoride source compared with the day before exposure. Release rates returned to baseline within 3 days. Within the time periods of the study, only the uptake/re-release of Fuji IX was adversely affected by late exposure. All the materials showed an enhanced uptake and release on repeated exposure to the external fluoride source. CONCLUSIONS: All the materials under test (Dyract, Fuji II LC, Vitremer and Fuji IX) released significant amounts of fluoride and reacted positively to exposure to an external fluoride source.
Cariostatic Agents↗
Acute changes in haematological parameters on cessation of smoking.
Cigarette smoking is known to affect many haematological parameters but little is known of their rate of return to normal on withdrawal of cigarettes. Two groups of chronic smokers were studied whilst smoking and in the 2 weeks after cessation. A rapid return towards normal was found in the elevated haemoglobin concentration, packed cell volume, red cell count, white cell count, neutrophil count, lymphocyte count and platelet count, indicating that at least some of the abnormalities in these parameters are an acute, reversible effect of cigarette smoking rather than being a response to tissue damage.
Adult↗
Conn's syndrome can cause malignant hypertension.
We present a case in which a patient, having already sustained an episode of malignant hypertension, was subsequently found to have an underlying Conn's adenoma. Ablation of the adenoma improved control of her hypertension. When a second adenoma developed in her remaining adrenal gland, control of her hypertension deteriorated.
Adenoma↗
Haemorheological changes in the very short term after abstention from tobacco by cigarette smokers.
A study was made of the haemorheological changes that took place in the days immediately following tobacco withdrawal from cigarette smokers. In both males and females substantial and persistent reductions in blood viscosity occurred within 2 d, the fall at high shear rate corresponding to about 8% while at low shear rate it was approximately twice as much. These changes were due partly to a fall in packed cell volume (PCV), but also to reductions in total plasma protein and fibrinogen concentrations which led to reductions in plasma viscosity and rouleaux formation. These plasma protein-related changes were less pronounced in the female group. The results indicate that, even in the very short-term, abstention from cigarettes leads to substantial improvements in the haemorheological profile of heavy smokers.
Adult↗
Problem-oriented approach to practice. I. Economic impact.
The problem-oriented system provides a unique management tool for medical practice. It follows basic management principles for any complex human endeavor (ie, define goals, set standards, audit performance to those standards, and assess results). The basic tool is the problem-oriented record, which demands that statements of medical action be explicit to permit audit. This concept can be extended to provide and assess care for an entire practice. Five years of cumulative data were assessed. The following changes were noted: (1) The ratio of patients to physicians doubled. (2) The total hospitalization rate fell by more than 20% and general medical portion by 60%. (3) Ambulatory use and cost decreased by approximately 20%. (4) Expenditures for services fell by 22%, while national expenditures for physician services increased by 28%.
Adult↗