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Biomedical subjects

W Crowe

Publications and source records attributed to W Crowe.

14 recordsLinked to original sources
PubMed1989

Trace element levels in the blood of workers in two steel works and a non-ferrous plant handling lead and cadmium compared with a non-exposed population.

The concentrations of 14 elements in the blood of steelworkers and industrial workers exposed to lead- and cadmium-containing dusts were measured and compared with a control group drawn from University and hospital laboratory staff. Measurements were also made of the concentrations of 20 elements in the dusts. Significantly elevated levels were observed for cadmium and lead in whole blood, but no other significant variations were noted. The concentrations of these two elements in the dusts confirmed the exposure of those groups showing high levels of cadmium and lead. High levels of iron or chromium in some of the dusts were not correlated with any changes in the mean blood levels of the exposed groups.

Air Pollutants, Occupational↗
PubMed1981

Anterior uveitis in Kawasaki's disease.

Kawasaki's disease (mucocutaneous lymph node syndrome) is an acute febrile illness primarily affecting children. Slit-lamp examinations of six children with kawasaki's disease, ranging in age from 22 months to 16 years, showed that five had anterior uveitis during the acute phase of the illness. Two of the children were treated with corticosteroids and cycloplegic drugs and three received no treatment. In all five, the anterior uveitis resolved completely within a few weeks.

Adolescent↗
PubMed1981

Follow-up ophthalmologic examinations in children with Kawasaki's disease.

We recalled 15 patients who had had Kawasaki's disease with documented bilateral conjunctival injection but who had not undergone slit-lamp examinations during the acute phase of the illness. Although anterior uveitis has been found in the acute phase of Kawasaki's disease, results of the follow-up studies (including slit-lamp examination, visual acuity testing, and assessment of pupillary reaction, muscle balance, and intraocular pressure) were normal in all 14 children.

Adolescent↗
PubMed1981

Ion transport and energy metabolism in brain.

The kinetics of extracellular K+ activity was compared to the availability of energy in the cortex of rats and gerbils exposed to anoxia, hypoxia, spreading depression, and ischemia. A combined K+/DC surface electrode was used alone or together with a fiber optic light guide in various experiments. All experiments were done on slightly anesthetized animals that were practically awake. The results can be summarized in the following conclusions: (1) Under conditions such as hypoxia or ischemia, K+0 showed a two-phase efflux kinetics, and a transition or critical point was reached where the response proceeds at a higher rate. This critical point was in the range of 10-16 mEq/1 potassium. (2) Availability of oxygen is necessary but not sufficient for a full rate of recovery from a long-term oxygen-deprivation insult. (3) There is an energy debt or energy-transduction bottleneck formed during a prolonged O2 insufficiency. This debt is reversed slowly during the recovery phase even when full restitution of O2 supply and blood flow has occurred.

Animals↗
PubMed1980

The interrelation between brain oxidative metabolism and extracellular potassium in the unanesthetized gerbil.

The unanesthetized gerbil model was used to study the interrelation between metabolic, electrical and ionic activities in the brain. A combined K+DC surface electrode with a fiber optic light guide was implanted above the parietal cortex and cemented to the skull. The subjects were exposed to various pathological and physiological conditions such as anoxia, hypoxia, spreading cortical depression, and ischemia. During anoxia a leakage of cellular K+e was detected simultaneously with an increased level of NADH. The recovery phase in a few animals was followed by a spreading depression phenomenon. Exposing the brain to spreading depression led to a typical oxidation cycle of NADH, and the shape of this cycle was affected by hypoxia. Unilateral carotid artery ligation induced localized ischemia that affected cellular and K+e responses to spreading depression. Bilateral carotid artery occlusion increased NADH concentration to its maximum level; as a result, K+e also accumulated. Complete restoration of NADH and K+e to normoxic levels occurred after a few minutes, depending on the duration of the occlusion.

Animals↗
PubMed1978

The dynamics of K+ leakage and recovery in cerebral ischemia.

A combination of K+/DC surface electrode and a fiberoptic fluorometric probe are applied to measurements in brain during cerebral ischemia. The kinetics of the responses of extracellular K+ activity and intracellular NADH fluorescence in the gerbil cerebrum following reversible carotid ligation are measured. K+e shows a two-phase response to carotid occlusion and an extended recovery phase following recirculation. The length of the recovery phase is dependent on the duration and severity of the ischemic period. In the gerbil model the degree of communication in the anterior circulation is variable, whereas a bilateral carotid occlusion is presumed to give complete cerebral ischemia. Pyridine nucleotide fluorescence serves as an indicator of the degree of ischemia. Bilateral carotid occlusions of up to 35 minutes in duration were performed. K+e reaches 30--50 mEq/liter in the extracellular space within the first two minutes. This represents cell depolarization and equilibration of K+ activity levels. Recovery appears to be complete in terms of the ability of the system to clear raised levels of K+e from the extracellular space.

Animals↗
PubMed1977

An immunofluorescent method using Crithidia luciliae to detect antibodies to double-stranded DNA.

The immunochemical specificity of the immunofluorescent Crithidia luciliae method for detection of antibodies to double-stranded DNA (dsDNA) was confirmed by demonstrating abolition of staining by DNase digestion and by absorption with dsDNA. This method was less sensitive than a Millipore filter method for detecting antibodies to DNA. It was positive only in subjects with systemic lupus erythematosus or drug-induced antinuclear factors. This technique appears suitable for study of the immunochemical characteristics fo antibodies to dsDNA.

Antibodies, Antinuclear↗
PubMed1977

Application of a solid membrane ion-selective electrode to in vivo measurements.

A solid membrane electrode containing a highly selective ion-complexing agent immobilized in a polymer membrane is applied to measurements in vivo from the surface of an organ. For the measurements reported here, an ion-complexing agent selective for potassium is incorporated in a silicone rubber membrane and applied to measure ion changes in the brain. Comparison is made to the measurements recorded with an ion-selective microelectrode in the cortical tissue. The surface electrode compares favorably with the microelectrode in terms of amplitude of response and response time for the changes seen in the phenomenon of cortical spreading depression of Leao. The methods reported here are amenable to a selection of ion measurements by incorporation of a suitable ion exchanger in a polymer membrane. Extracellular ion activity is monitored in the anesthetized animal by holding the electrode in a balanced suspension which provides a light, flexible contact to the organ of interest. In the unanesthetized animal, when recording from the brain, the electrode is fixed in a skull-implanted cannula.

Animals↗
PubMedDate not supplied

First report of intramyocardial pH in man: I. Methodology and initial results.

Continuous in vivo measurements of intramyocardial pH (MpH) have not been previously obtained in man. To achieve this goal, we developed in our laboratory a new, steel-jacketed, glass electrode, and circumvented temperature-related problems by recording the output in millivolts along with the adjacent myocardial temperature. A computer program was devised to calculate MpH in accordance with the Nernst equation. The need in this system for a remote, subcutaneous, reference electrode prompted two sets of experiments. The first set of experiments demonstrated in vitro that the adverse effect of varying the temperature of the reference electrode on the calibration of the pH electrode could be avoided if the reference electrode was placed in a potassium chloride (KCl) solution outside the body and connected to the subcutaneous tissues with a salt bridge. The second set of experiments, which were conducted in vivo in dogs, demonstrated that MpH measurements made with the reference electrode in the limb were not affected by ischemic electrocardiographic changes. This system was then used successfully in 10 patients undergoing coronary artery bypass surgery. Reliable, reproducible, and uniform changes were observed. Baseline MpH prior to revascularization was 6.81 +/- 0.07. Myocardial protection with cold K+ cardioplegia resulted in a significant rise in MpH to 7.45 +/- 0.06. Throughout the period of cross-clamping, MpH remained high. After revascularization and discontinuation of cardiopulmonary bypass, MpH stabilized at 6.93 +/- 0.04.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗