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E O'Brien

Publications and source records attributed to E O'Brien.

At least 19 recordsLinked to original sources
PubMed1995

The ambulatory blood pressure in normotensive and hypertensive subjects: results from an international database.

OBJECTIVE: To delineate more precisely an operational threshold for making clinical decisions based on ambulatory blood pressure (ABP) measurement by studying the ABP in subjects who were diagnosed as either normotensive or hypertensive by conventional blood pressure (CBP) measurement. SUBJECTS: Twenty-four research groups recruited 7069 subjects. Of these, 4577 were normotensive (systolic CBP < or = 140 mmHg and diastolic CBP < or = 90 mmHg) and 1773 were hypertensive (systolic CBP > or = 160 mmHg and/or diastolic CBP > or = 90 mmHg). Of the latter, 1324 had systolic and 1310 had diastolic hypertension. RESULTS: Ninety-five percent of the normotensive subjects had a 24-h ABP below (systolic and diastolic, respectively) 133 and 82 mmHg. Of the patients with systolic hypertension, 24% had a 24-h systolic ABP of < 133 mmHg. Similarly, 30% of those with diastolic hypertension had a 24-h diastolic ABP of < 82 mmHg. The probability that hypertensive patients had a 24-h ABP below these thresholds was higher in women than in men, increased with age and was 2- to 4-fold greater if the CBP of the patient had been measured at only one visit and if fewer than 3 CBP measurements had been averaged to establish the diagnosis of hypertension. By contrast, for each 10-mmHg increment in systolic CBP, this probability decreased by 54% for the 24-h systolic ABP and by 25% for the 24-h diastolic ABP, and for each 5 mmHg increment in diastolic CBP it increased by 6 and 9%, respectively. CONCLUSION: The ABP distributions of the normotensive subjects included in the present international database were not materially different from those in previous reports in the literature. One-fifth to more than one-third of the hypertensive patients had an ABP which was below the 95th centile of the ABP in normotensive subjects, but this proportion decreased if the hypertensive patients had shown a higher CBP upon repeated measurement. The prognostic implications of elevated CBP in the presence of normal ABP remain to be determined.

Adolescent↗
PubMed1995

Mechanism research of cryoanalgesia.

The sciatic nerves of rabbits were frozen at different temperatures (-20 degrees C, -60 degrees C, -100 degrees C, -140 degrees C, and -180 degrees C). The morphology and function of the frozen nerves were examined with light microscopy (hematoxylin and eosinophilin stain and a histochemical thiocholine method) and electron microscopy. The function of the nerve after freezing was assessed using short latency somatosensory evoked potentials, sensory conduction velocity, and electromyogram at various intervals after freezing. There were no changes in morphology or function of nerves cryolesioned at -20 degrees C. The nerve fibers cryolesioned at -60 degrees C showed signs of freezing degeneration and lost their conductive function although, these nerves all recovered. Approximately half of nerve fibers cryolesioned at -100 degrees C showed Wallerian degeneration, and although the time to remyelination was delayed, nerve regeneration was still complete. At -140 degrees C and -180 degrees C the nerve fibers showed immediate necrosis, with destruction of basal membranes and proliferation of collagen fibers. The results explained the mechanism of cryoanalgesia. Our study demonstrates that cryo-temperatures lower than -140 degrees C will cause permanent alterations in nerve morphology and function, whereas warmer temperatures do not result in permanent nerve damage and are therefore not likely to provide long-term analgesia to patients.

Analgesia↗
PubMed1995

State of the market. A review of ambulatory blood pressure monitoring devices.

The introduction of 24-hour ambulatory blood pressure measurement into clinical practice created a large market for ambulatory blood pressure measurement devices. Forty-three such devices from 31 manufacturers or suppliers are now available to satisfy a market demand that is likely to increase. The aim of this article is to identify the devices available and then to examine critically any validation studies assessing accuracy and performance. Of the 43 devices available 18 have been validated according to the protocols of the Association for the Advancement of Medical Instrumentation (AAMI) or the British Hypertension Society (BHS) in 25 reported studies. In 9 of these studies the protocol was not adhered to, and the results, which are therefore questionable, are noted but not considered further. Fourteen devices were evaluated according to the accuracy criteria of both protocols, and of these 9 fulfilled the requirements. From this review of 43 devices on the market it may be concluded that, at the time of writing, there is published evidence for only 9 devices meeting the generally accepted AAMI and BHS criteria for accuracy and performance; these are the A&D TM-2420 models 6 and 7 and TM-2421, CH-Druck, Nissei ABPM DS-240, Profilomat, QuietTrak, and SpaceLabs SL-90202 and SL-90207.

Blood Pressure Monitoring, Ambulatory↗
PubMed1994

Game, set and MRCP.

Explore the source record for details and available documents.

Clinical Competence↗
PubMed1994

Cloning of the glucose 6-phosphate dehydrogenase gene from Plasmodium falciparum.

Glucose 6-phosphate dehydrogenase (G6PD) deficiency is one of the human genetic traits that confer relative resistance against malaria caused by Plasmodium falciparum. It has been previously shown that this organism, during its intraerythrocytic development, produces its own G6PD, which has properties different from those of human G6PD. In order to investigate the role of this enzyme in parasite-host cell interactions, we have isolated the G6PD gene from Plasmodium falciparum as a set of overlapping lambda gt11 clones. By sequence analysis we have found a single open reading frame, uninterrupted by introns, coding for a protein of 910 amino acids, almost twice as long as any previously sequenced G6PD molecule. The P. falciparum G6PD mRNA is 5.1 kb in size and has an exceptionally long 5' untranslated region of some 1000 nucleotides. We have mapped the G6PD gene to chromosome 14. The C-terminal portion of the predicted protein, from amino acid 310-910 (except for an 'insert' of 62 amino acids), has 39% homology to human G6PD, with a number of characteristic, fully conserved peptides. The N-terminal portion of the predicted protein has no homology to G6PD, but it contains a peptide in which 7 out of 12 amino acids are identical to the putative glutathione binding site of human glutathione S-transferase.

Amino Acid Sequence↗
PubMed1994

Using Hawksley random zero sphygmomanometer as a gold standard may result in misleading conclusions.

We combined a database of paired blood pressure measurements taken using the Hawksley random-zero sphygmonanometer and a standard mercury sphygmomanometer and a database of paired measurements made on a SpaceLabs 90202 ambulatory blood pressure recorder and standard sphygmomanometer to determine how the SpaceLabs 90202 would have fared if it had been assessed against the Hawksley random-zero sphygmomanometer instead of a standard sphygmomanometer. The pooled database contained 255 triplicate readings. Using the standard sphygmomanometer as gold standard, the Spacelabs had a median error of 2 mm/Hg for both systolic and diastolic. Against the Hawksley random-zero sphygmomanometer, median error was -3 mm systolic and -6 mm diastolic. The proportion of errors > 10 mm rose from 11% (systolic) and 9% (diastolic) with the standard sphygmomanometer to 16% and 29% with the Hawksley random-zero sphygmomanometer. Because it underestimates systolic and diastolic pressures, the use of the Hawksley random-zero sphygmomanometer as a gold standard may have resulted in misleading conclusions about performance of some automated BP recorders.

Adult↗