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Biomedical subjects

B M Buckley

Publications and source records attributed to B M Buckley.

At least 19 recordsLinked to original sources

Healthy ageing: ageing safely.

The population of the developed world is steadily ageing. In the European Union, approximately 22% of persons are over 60 years of age and this is projected to increase to more than 27% by the year 2020. This has major implications for health care resources and the productive workforce. Ageing is accompanied by a decline in the physiological reserve of all organ systems, compromising homeostasis and resistance to disease. Thus, when disease develops in the elderly it has an increased impact on organ systems not directly involved. This places older people at risk for multiple simultaneous pathologies. Treatment often requires polypharmacy, which often is accompanied by drug interactions and adverse reactions. The pattern of sequential and comorbid disease often means that the later years of life are associated with an accumulating toll of disability, which in turn consumes a high proportion of health-care resources. The major goal of health care in the elderly should be to compress morbidity into the end of the normal lifespan. To achieve this, it will be necessary to redefine our approaches to treatment in the elderly and to develop an evidence base to inform this process.

Aged↗

The design of a prospective study of Pravastatin in the Elderly at Risk (PROSPER). PROSPER Study Group. PROspective Study of Pravastatin in the Elderly at Risk.

The PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) is a randomized, double-blind, placebo-controlled trial designed to test the hypothesis that treatment with pravastatin will diminish risk of subsequent major vascular events in a cohort of men and women (70 to 82 years old) with preexisting vascular disease or significant risk of developing this condition. Five thousand eight hundred four men and women in addition to receiving advice on diet and smoking, have been randomized equally to treatment with 40 mg pravastatin/day or matching placebo in 3 centers (Cork, Ireland, Glasgow, Scotland, and Leiden, The Netherlands). Following an average 3.5-year intervention period, a primary assessment will be made of the influence of this therapy on major vascular events (a combination of coronary heart disease, death, nonfatal myocardial infarction, and fatal and nonfatal stroke). A number of additional analyses will also be conducted on the individual components of the primary end point, on men, on women, and on subjects with and without previous evidence of vascular disease. Finally, an assessment will be made of the effects of treatment on cognitive function, disability, hospitalization or institutionalization, vascular mortality, and all-cause mortality.

Aged↗

Methemoglobinemia following ingestion of a monolinuron/paraquat herbicide (Gramonol)

A 59-year-old man ingested a mouthful of Gramonol with suicidal intent and was admitted to a local hospital six and a half hours later. It was noted that he looked "ashen grey" and was centrally cyanosed. The methemoglobin and plasma paraquat concentrations performed on arrival at the Regional Poisons Treatment Unit eight hours after paraquat ingestion were 52% and 1100 micrograms/L respectively; the administration of methylene blue reversed methemoglobinemia within two hours. The patient suffered extensive paraquat-induced oral, and probably esophageal, ulceration and developed multiple organ (particularly renal, respiratory and hepatic) failure and died some 10 days later. This is the most severe case of Gramonol poisoning reported both in terms of the amount of paraquat ingested and the concentration of methemoglobin formed. We believe that the methemoglobinemia in this patient was caused by monolinuron not paraquat.

Fatal Outcome↗

Recommendation on sampling, transport, and storage for the determination of the concentration of ionized calcium in whole blood, plasma, and serum. IFC Scientific Division, Working Group on Ion-Selective Electrodes (WGSE).

The substance concentration of ionized calcium (cCa 2+) in blood, plasma, or serum preanalytically may be affected by pH changes of the sample, calcium binding by heparin, and dilution by the anticoagulant solution. pH changes in whole blood can be minimized by anaerobic sampling to avoid loss of CO 2, by measuring as soon as possible, or by storing the sample in iced water to avoid lactic acid formation. cCa 2+ and pH should be determined simultaneously. Plasma or serum: If centrifuged in a closed tube and measured immediately, the pH of the sample will be close to the original value. If there has been a delay between centrifugation and measurement, causing substantial loss of CO 2, equilibration of the sample with a gas mixture corresponding to pCO 2 = 5.3 kPa prior to the measurement is recommended. Conversion of the measured values to cCa 2+ (7.4) is only valid if the pH is in the range 7.2-7.6. Ca 2+ binding by heparin can be minimized by using either of the following: 1) a final concentration of sodium or lithium heparinate of 15 IU/mL blood or less; or 2) calcium-titrated heparin with a final concentration of less than 50 IU/mL blood. Dilution effect can be avoided by use of dry heparin in capillaries or syringes.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Chemical Analysis↗

Theophylline analysis at the chest clinic--comparison of a portable versus conventional system.

The running cost and clinical application of a new, portable, direct-injection, high-performance, liquid chromatograph for the measurement of theophylline was compared with conventional laboratory-based analysis by studying the two methods in two parallel chest clinics. Thirty-six patients were managed with the portable method and 33 by the conventional system. They were already receiving theophylline preparations for treatment of their asthma or chronic airflow limitation. Over the 12-week period of study, the percentage of patients with levels in the therapeutic range rose from 33% to approximately 87% in both clinics, but this change was achieved in only 6 weeks using the portable system. Patients whose theophylline levels were increased into the therapeutic range had improved symptom scores as measured by visual analogue scales but we were unable to demonstrate any significant change in spirometry. The cost of the portable system compared favourably with laboratory analysis, and had the additional benefit of quicker detection of non-compliance and facility for discussion with the patients at the time of consultation.

Adult↗

Protein interference with ion-selective electrode measurement depends on reference electrode composition and design.

There is controversy about whether protein interferes with ion measurements using ion-selective electrodes. We have investigated the effects of changes in the salt-bridge composition of five commercially available analysers with open, membrane-restricted or porous frit-restricted reference electrode junctions on measurements of an albumin solution prepared by gel filtration. When the manufacturers' salt bridges were used, instruments with open or membrane-restricted junctions showed apparent increases in the activity of ionized calcium, sodium and potassium in the presence of protein. When the hypertonic bridge solutions were replaced with 150 mmol/L potassium chloride this increase disappeared. The instrument with a porous frit-restricted junction showed no protein effect, but its response to changes in sample sodium chloride concentration in protein-free solution suggested that its junction was functionally equivalent to that formed with an isotonic sodium chloride bridge. Our results emphasize that liquid junction design and composition affect ion measurements in protein-containing solutions and suggest that the use of hypertonic bridge solutions for biological samples needs to be re-examined.

Calcium Chloride↗

International Federation of Clinical Chemistry (IFCC) scientific division IFCC recommendation. Recommendation on sampling, transport and storage for the determination of the concentration of ionized calcium in whole blood, plasma and serum.

The substance concentration of ionized calcium (cCa2+) in blood, plasma or serum preanalytically may be affected by pH changes of the sample, calcium binding by heparin, and dilution by the anticoagulant solution. pH changes in whole blood can be minimized by anaerobic sampling to avoid loss of CO2, by measuring as soon as possible or by storing the sample in iced water to avoid lactic acid formation. cCa2+ and pH should be determined simultaneously. Plasma or serum: if centrifuged in a closed tube and measured immediately the pH of the sample will be close to the original value. If delay has occurred between centrifugation and the measurement, causing substantial loss of CO2, equilibration of the sample with a gas mixture corresponding to PCO2 = 5.3 kPa prior to the measurement is recommended. Conversion of the measured values to cCa2+ (7.4) is only valid if the pH is in the range 7.2-7.6 Ca2+ binding by heparin can be minimized by using either of the following: a final concentration of sodium or lithium heparinate of 15 IU/ml blood or less, by use of calcium titrated heparin with a final concentration less than 50 IU/ml blood. Dilution effect can be avoided by use of dry heparin in capillaries or syringes. When heparin solutions are used errors due to dilution or calcium binding can be reduced using syringes with a heparin solution containing free calcium ions corresponding to the mean concentration of ionized calcium in normal plasma. Conditions for blood collection, storage, and transport to avoid preanalytical errors are described.

Blood Chemical Analysis↗

International Federation of Clinical Chemistry (IFCC), scientific division: IFCC recommendation on sampling transport and storage for the determination of the concentration of ionized calcium in whole blood, plasma and serum.

The substance concentration of ionized calcium (cCa2+) in blood, plasma or serum preanalytically may be affected by pH changes of the sample, calcium binding by heparin, and dilution by the anticoagulant solution. pH changes in whole blood can be minimized by anaerobic sampling to avoid loss of CO2, by measuring as soon as possible or by storing the sample in iced water to avoid lactic acid formation. cCa2+ and pH should be determined simultaneously.

Blood Coagulation↗

Cardiac enzyme changes in elderly fallers.

The pattern of enzyme changes in elderly fallers admitted to an acute geriatric unit was investigated. Creatine kinase (CK), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) activities were measured daily for 3 days after admission in all patients in whom a fall preceded admission. Of 270 patients, 52 (19%) had fallen prior to admission, of whom five (10%) had an acute myocardial infarction (AMI). In fallers without an AMI in whom a history was available, CK and AST activities were significantly higher (p less than 0.05) in patients who had spent more than 1 hour on the floor than in those who had spent less than 1 hour. No other clinical factor affected enzyme activities. CK and AST activities were raised in 66% and 40%, respectively, of fallers without an AMI. Elevation of CK and AST activities in elderly fallers is likely to be a result of the fall itself rather than of an AMI.

Accidental Falls↗

The effective use of cardiac enzymes and electrocardiograms in the diagnosis of acute myocardial infarction in the elderly.

The diagnosis of acute myocardial infarction (AMI) in the elderly is difficult and often depends on the results of investigations. In a 3-month prospective study, 270 patients admitted to an acute geriatric unit were studied to determine the most effective diagnostic strategy for the diagnosis of AMI, and to assess the value of screening acute geriatric admissions for AMI. Patients were assessed clinically and investigated with serial electrocardiograms and measurements of serum creatine kinase (CK), aspartate aminotransferase (AST), and lactate dehydrogenase activities on three consecutive days after admission. Measurement of serum activity of CK and AST had a diagnostic sensitivity of 100% and specificity of 86.8% for AMI. This was the optimum combination of cardiac enzymes in the diagnosis of AMI. Although electrocardiograms on the first two days of admission had a low diagnostic sensitivity (33.3%) their usefulness was their high positive predictive value (100%) when characteristic of an AMI. AMI was considered in the differential diagnosis of 79 patients (29%). All 25 patients (9%) who had an AMI were in this group, and therefore screening all geriatric admissions for AMI is not clinically justified.

Aged↗

Simplified oral pancreatic function test.

The standard Bentiromide test and a new modified test using p-aminosalicylic acid (PAS) as a pharmacokinetic marker for p-aminobenzoic acid (PABA) have been evaluated in the detection of pancreatic exocrine insufficiency in children. The conventional two day test using a colorimetric assay for urinary PABA discriminated poorly between five children with pancreatic insufficiency and 13 others with normal pancreatic function. Two further groups of patients, comprising 28 with pancreatic exocrine insufficiency and 20 with normal pancreatic function underwent the modified test, and urine samples were analysed by high performance liquid chromatography. The results showed a complete separation between groups. The use of PAS eliminates a number of sources of error inherent in a two day Bentiromide test and provides a simplified and accurate diagnostic test for pancreatic insufficiency. The PABA-PAS modified test enables collection of the urine to be done during a single six hour period.

4-Aminobenzoic Acid↗

Plasma sodium and potassium measurement: minimising ISE-flame differences using specimens from patients.

Experience in clinical chemistry of direct reading ion-selective electrode analysers for the measurement of plasma Na+ and K+ concentrations has shown that the results obtained on any specimen may vary significantly from one make of instrument to another. To overcome these differences, the European Working Group on ISEs of the IFCC Expert Panel on pH, Blood Gases and Electrolytes have proposed that instruments should be standardised to report Na+ and K+ concentrations in undiluted plasma to agree with flame emission spectrometry in samples with normal plasma water bicarbonate concentrations and normal pH. In designing and setting the calibration of a new ISE analyser for Na+ and K+, the Corning 614, the manufacturer has attempted to satisfy this proposal using a large number of specimens obtained from patients. This paper presents details of the procedure used and the results of an independent evaluation of its validity in routine clinical practice.

Electrodes↗