Biomedical subjects
J E O'Brien
Publications and source records attributed to J E O'Brien.
Relationship between dystonia and serum calcium levels.
The relationship between acute dystonic reactions and serum calcium levels in 17 acutely psychotic patients was studied. Previous studies have implicated an association between a lowered serum calcium value and acute dystonia. This study failed to note a significant incidence of hypocalcemia in a group of psychotic patients. It is not known whether other factors related to calcium-magnesium balance may be related to dystonia.
Incontinentia pigmenti. A longitudinal study.
We describe 15 patients with incontinentia pigmenti whom we have followed up from two to 11 years. This longitudinal approach allowed us to observe the course of the skin lesions and developmental progress of these children. We found that in contrast to what has been previously reported in most of the literature, the bullous and verrucous lesions do not always resolve during the first or second year of life and may recur throughout childhood. Although most patients with incontinentia pigmenti are of normal intelligence, those with neonatal seizures have a poor prognosis for normal development.
Cardiac care for children with Down's syndrome.
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The drug scene today and its effect on mortality.
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Evaluation of API microtube GT system for detection of germ tube production by clinically significant yeasts.
A total of 152 fresh consecutive yeast isolates were tested for their ability to produce germ tubes by the API GT system (Analytab products, Plainview, N.Y.) and by a conventional method. The API system was found to be less sensitive than the conventional method. The costs per test by the API system and the conventional method were $0.76 and $0.39, respectively.
A surface bolus material for high-energy photon and electron therapy.
The authors describe a useful bolus material for therapy with high-energy photons and electrons (greater than 1 MeV). Qualities evaluated included flexibility, transparency, tissue equivalence (re radiation interactions), stability at high doses, durability, lack of toxicity, ease in cleaning, low flammability, and cost. Using a parallel-plate ionization chamber and 60Co, 4-, and 10-MV photons as well as 6- and 18-MeV electrons, maximum deviation from water-equivalent values was approximately 2 mm for 6-MeV electrons. The material comes in large sheets of precise thickness (+/- 0.5 mm) which can be cut and layered to form more complex shapes.
Comparison of lidocaine and 2-chloroprocaine in paracervical block: clinical effects and drug concentrations in mother and child.
2-Chloroprocaine (CP) has recently been recommended as a less toxic alternative to amide-type local anesthetics due to its rapid metabolism. A double-blind, randomized study comparing CP to lidocaine when used for paracervical block was carried out. Twenty-nine patients received CP, while 31 received lidocaine. None of the 60 mothers developed adverse side effects. Adequate pain relief was achieved in 28 cases in each group, with a mean duration of 40 min regardless of the anesthetic. No change in uterine activity was observed. In the CP group one fetus had mild bradycardia, while two in the lidocaine group had severe, and three mild bradycardia within 5-7 min after the block. Low concentrations of CP were detected in the venous blood of 2 of 29 mothers and in the umbilical venous blood of their babies. Measurable amounts of its metabolite, 2-chloro-4-aminobenzoic acid (CABA), were found in all 13 samples of maternal blood 5 min after PCB and in 6 of 27 maternal samples at birth. Traces of CABA were found in umbilical venous blood in three neonates; in a fourth, a level of 1,000 ng/ml was found. In contrast, unmetabolized lidocaine was found in all maternal samples and in all but one of the cord samples at birth. Concentration of lidocaine in cord blood at delivery ranged from less than 100 to 4,000 ng/ml and were similar for both arterial and venous samples. No correlation could be demonstrated between levels of local anesthetics in the cord samples and the frequency or severity of fetal bradycardia regardless of the anesthetic.
Help seeking by the frail elderly: problems in network analysis.
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Metabolism and measurement of chloroprocaine, an ester-type local anesthetic.
Blood levels of intact chloroprocaine were determined using a GLC procedure capable of detecting as little as 10 ng of chloroprocaine/ml of blood. It was necessary to detective plasma cholinesterases in collected samples by adding echothiophate iodide to blood sampling tubes. An extraction procedure, followed by a TLC separation and spectrodensitometric assay, was developed for measurement of the metabolite 2-chloro-4-aminobenzoic acid in plasma and urine. With these procedures, data were obtained showing that chloroprocaine is hydrolyzed rapidly by plasma cholinesterases. No unchanged drug could be detected in any blood samples obtained from volunteers who received chloroprocaine by intravenous infusion or from obstetric patients who had epidural anesthesia during labor and delivery. Blood levels of 2-chloro-4-amino-benzoic acid rose promptly with the administration of chloroprocaine and declined rapidly after drug administration. Most of the metabolite was recovered in urine.
Growth hormone deficiency in a patient with Silver-Russell syndrome.
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Enzyme-multiplied immunoassay.
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GLC determination of doxepin plasma levels.
A procedure is described for extracting doxepin, a tricyclic antidepressant, from plasma and subsequently measuring its concentration by GLC. The developed technique permits the resolution and quantitative determination of the cis- and trans-isomers of doxepin as well as its desmethyl metabolite. The method allows precise, reliable measurement of the drug and one of its metabolities in concentrations as low as 10 ng/ml of plasma.
Effects of de-icing salt on ground water characteristics.
The effect of "road salt" on the characteristics of Massachusetts drinking water supplies has been significant and cumulative rather than transient or seasonal. De-icing salt is essentially all sodium chloride. Calcium chloride accounted for only three percent of the total salt used. However, hardness content, as well as sodium ion concentration, has increased greatly in ground waters in the past decade. The changing composition of our water supplies has agricultural, economic, and public health implications. This study attempts to quantify the stoichiometry of these changes in concentration, which are in part due to an ion-exchange mechanism in the soil.
Serum iron levels in ostensibly normal people.
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Determination of amphetamine and phentermine in biological fluids.
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The general problem of program evaluation: the researchers' perspective.
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