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Biomedical subjects

I M Baird

Publications and source records attributed to I M Baird.

At least 19 recordsLinked to original sources
PubMed1992

Improvement in left ventricular function after rapid weight loss in obesity.

The effect of rapid weight reduction on left ventricular function and blood pressure was studied in 34 obese subjects, who all weighed more than 30% above their ideal body weight. Subjects with co-existing hypertension (N = 15) and proven coronary artery disease (N = 9) were included to assess contributions from these factors. Blood pressure (BP) was measured both indirectly and by direct ambulatory intra-arterial methods. Radionuclide ventriculography was performed at rest and at exercise, before and after dieting, which was supervised in hospital (daily intake 330 kCal day-1 for 4 weeks). Dieting induced a weight loss of (mean +/- SD) 9.6 +/- 3.5 kg (P less than 0.0001) in the whole group. The mean daytime intra-arterial blood pressure fell from 157 +/- 23/90 +/- 15 to 144 +/- 21/85 +/- 13 mmHg (P less than 0.0001). The fall in ambulatory intra-arterial diastolic blood pressure did not reach significance in the normotensive and ischaemic groups. The mean resting left ventricular ejection fraction (LVEF) in the whole group showed a significant reduction after weight loss from 61 +/- 10% to 56 +/- 6% (P less than 0.005). Although the individual groups showed a fall in LVEF, the effect was most marked in the hypertensive group, from 65 +/- 9% to 57 +/- 5% (P less than 0.002). Before dieting none of the groups achieved a 'normal' 5% rise in LVEF above basal in response to exercise, the hypertensive and the ischaemic groups both showing non-significant falls. This phenomenon was, however, reversed after weight loss.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Early diagnosis of acute myocardial infarction by CK-MB mass measurements.

We have studied the changes in creatine kinase (CK) and creatine kinase MB (CK-MB) activity and concentration for the diagnosis of acute myocardial infarction in 73 patients admitted to the coronary care unit with cardiac symptoms of 12 h duration or less. Serial blood samples were obtained for an 8 h period following admission and CK, CK-MB activity and concentration measured. We compared the performance of single values at optimized diagnostic cut-offs and incremental change (log slope) for all three measurements. CK slope combined with CK-MB concentration measurements allowed accurate diagnosis at 4 h from admission. CK-MB concentration determination 8 h from admission (12-16 h from the onset of chest pain) was the most efficient single measurement. Rapid diagnostic categorization and possible selection of patients for thrombolysis in patients with an uncertain admission diagnosis is possible by these techniques.

Adult↗
PubMed1991

Circadian variation and blood pressure: response to rapid weight loss by hypocaloric hyponatraemic diet in obesity.

Ambulatory intra-arterial blood pressure was monitored in 15 obese hypertensive and 10 obese normotensive subjects weighing more than 30% of their ideal body weight. Measurements were taken before and after 1 month in hospital on a diet of 330kCal/day designed to ensure 34 g protein and 65 mmol sodium. Mean +/- s.d. body mass index in the whole group fell from 40.8 +/- 7.6 to 37.2 +/- 7.4 kg/m2 (P less than 0.0001). Daytime intra-arterial blood pressure fell from 176 +/- 19/102 +/- 14 to 162 +/- 16/95 +/- 14 mmHg (P less than 0.0005 and P less than 0.002) in the hypertensive group and from 141 +/- 15/82 +/- 5 to 131 +/- 13/79 +/- 4 mmHg (P less than 0.005 for systolic pressure) in the normotensive group. Circadian variation of systolic intra-arterial blood pressure comparing the mean daytime with the mean night-time blood pressure recordings showed a day-night difference of 27 +/- 10 mmHg in the normotensive group compared with 12 +/- 13 mmHg in the hypertensive group (P less than 0.01). This trend was reversed after weight loss, when the normotensive group showed a day-night difference of 20 +/- 13 mmHg compared with 18 +/- 17 mmHg in the hypertensive group. Thus, circadian variation of systolic intra-arterial blood pressure in the hypertensive group was significantly (P less than 0.01) reduced compared with the normotensive group prior to, but not after, weight loss. These data show that, in obese subjects, weight loss produced a significant reduction in ambulatory intra-arterial blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Metabolic response to low- and very-low-calorie diets.

We compared the metabolic effects of 8-wk caloric restrictions with 330 or 780 kcal/d in two groups of eight obese hospitalized subjects; six control subjects were also studied. Loss of weight but not of adipose tissue was significantly greater on the 330-kcal/d diet. It is likely that dehydration rather than protein catabolism was responsible for additional loss of fat-free mass in the 330-kcal/d group because the nitrogen deficit was not excessive. The thermic response to food was blunted only in the 330-kcal/d group whereas resting oxygen uptake decreased by equal amounts in both groups. There was a decrease in 24-h urinary noradrenaline in the 330-kcal/d group but plasma fT4 was sustained when compared with the 780-kcal/d group; fT3 decreased significantly more quickly in the 330-kcal/d group. There was no correlation between plasma hormone levels and changes in oxygen uptake. Hunger scores were greater on the 780-kcal/d diet.

Adult↗
PubMed1989

Effect of the gastric balloon versus sham procedure on weight loss in obese subjects.

The mechanism by which intragastric balloons induce weight loss is not known, although they may act simply by reducing the amount of food needed to induce satiety. The knowledge that a balloon is present may influence the patients' eating patterns and reduce caloric intake and weight. In order to test whether the balloon or the secondary psychological effect caused weight loss, a double blind balloon versus sham procedure was devised with both groups receiving identical outpatient dietary advice (800 kcal/day). Twenty four obese women with body mass index greater than 30 kg/m2 from an obesity clinic were studied. Twelve had the balloon and 12 the sham procedure. The balloon was removed after three months and the patients were followed for a further three months. There was significantly greater weight loss in the balloon group, mean weight loss (SD) of 7.33 (6.12) kg compared with the sham group, mean weight loss (SD) of 3.33 (3.9) kg (p less than 0.05). Weight loss was not maintained in all patients after balloon removal. Side effects were more common in the balloon group (abdominal pain, nausea, and vomiting) but resolved by the second week. We conclude that the intragastric balloon is a safe and effective method of inducing weight loss in well motivated obese patients.

Adolescent↗
PubMed1989

Diagnosis of acute myocardial infarction from sequential enzyme measurements obtained within 12 hours of admission to hospital.

A prospective study was made of sequential changes in serum creatine kinase (CK) and CK-MB isoenzyme activity within the 12 hours following admission to the coronary care unit on 65 patients with recent chest pain. CK determinations were performed in the laboratory or in the coronary care unit using a dry reagent strip analyser. Slope values for log CK/hour and log CK-MB/hour were calculated, used to confirm or exclude the diagnosis of myocardial infarction, and compared with diagnosis by conventional means. Compared with retrospective diagnosis using all available information, the CK slope had a sensitivity of 100% and a specificity of 94%. This compared with a sensitivity of 94% and specificity of 90% for diagnosis using upper reference limits alone. Determination of CK slope permits very rapid and accurate biochemical confirmation or exclusion of myocardial infarction and the possibility of performing the measurements on the coronary care unit. It additionally offers the prospect of major cost savings resulting from early discharge or transfer from the coronary care unit.

Adult↗
PubMed1989

Cardiovascular changes in obese subjects on very low calorie diet.

The effect of 330 kcal/day diet on cardiac function, blood pressure and cardiac chambers was studied in 34 obese subjects, using radionuclide ventriculography, intra-arterial ambulatory blood pressure recording and echocardiography. The group included 15 hypertensives and nine with coronary artery disease. After 4 weeks dieting, mean body weight fell from 105.6 +/- 22 kg to 96.1 +/- 19 kg (P less than 0.001), mean blood pressure fell from 157 +/- 23 to 144 +/- 21 mmHg systolic and 90 +/- 15 to 85 +/- 13 mmHg diastolic (P less than 0.001). The resting left ventricular ejection fraction after dieting fell significantly only in the hypertensive group (P less than 0.0005). Left ventricular ejection fraction response to exercise was impaired in all subjects. After weight loss this returned to normal except in the coronary artery disease group. There was a significant reduction in left ventricular internal dimensions, left ventricular fraction shortening and left ventricular mass after weight loss.

Adult↗
PubMed1984

Metabolic acidosis induced by carbonic anhydrase inhibitors and salicylates in patients with normal renal function.

Two young patients with unimpaired renal and hepatic function were found to have developed metabolic acidosis after treatment for glaucoma and joint pain with a combination of salicylates and carbonic anhydrase inhibitors in normal doses. Carbonic anhydrase inhibitors appear to interact with salicylates to produce serious metabolic acidosis in patients without the predisposing factors generally considered to constitute risks. It is recommended that treatment combining salicylates and carbonic anhydrase inhibitors is either kept to a minimum or avoided.

Acetazolamide↗
PubMed1983

SeHCAT absorption: a simple test of ileal dysfunction.

A new selenium-labelled synthetic bile salt SeHCAT (taurine conjugate of 23-[75Se]-25-homocholic acid) was assessed as a test of ileal dysfunction in 20 patients with inflammatory bowel disease (IBD). Whole body retention of SeHCAT was compared with tests of vitamin B12 absorption (Schilling test and whole body retention) and the cholylglycine-1-14C breath test and faecal isotope excretion. Clear differentiation, with no overlap was obtained between 10 normal subjects and patients with ileal disease/resection in the SeHCAT 7-day retention results. The Schilling test was more sensitive; enabling discrimination between patients with limited and extensive ileal disease/resection. An unexpected rise in SeHCAT retention was observed in patients with colonic IBD. The 7-day SeHCAT retention is a safe, simple screening test for ileal dysfunction and has practical advantages compared with the Schilling test.

Adult↗
PubMed1982

Lymphocyte blastogenic responses to L. pneumophila in acute Legionellosis.

Thirteen patients with acute Legionellosis were studied. Acute serologic studies obtained within the first two weeks of illness were non-diagnostic in 10 of 13 cases. Lymphocyte blastogenic responses to sonicated L. pneumophila were much higher in patients with acute disease (mean net cpm +/- SEM = 66,786 +/- 15,428) than in subjects without a history of Legionellosis (11,800 +/- 1,760) p less than 0.01. Eleven of the 13 patients with acute Legionellosis had net cpm greater than 17,000. Lymphocytes from six patients with acute non-Legionnaires' pneumonia had mean cpm of 3,769 +/- 909 (p less than 0.01). Blastogenic response to L. pneumophila appears to occur earlier than the production of measurable antibody and may be a useful adjunct to diagnosis.

Adult↗
PubMed1982

Cord blood lymphocyte transformation responses to Legionella pneumophila.

Cord blood lymphocytes were obtained from 94 neonates for transformation assays with sonicated and partially Legionella antigens and phytohemagglutinin. The Legionella antigens gave mean stimulation indices (SI) of approximately three times the background. The nonspecific mitogen phytohemagglutinin gave mean SI of 23 times the background. There was some minor nonspecific stimulation of cord blood lymphocytes by Legionella antigens but not enough to account for the SI seen in patients with Legionnaires' disease (48 +/- 14).

Fetal Blood↗