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Biomedical subjects

K O Ash

Publications and source records attributed to K O Ash.

79 records · Page 5Linked to original sources
PubMed1968

Chemical sensing: an approach to biological molecular mechanisms unsig difference spectroscopy.

Stimulation of preparations of rabbit olfactory epithelium with aqueous solutions containing the odorants linalool or inalyl isobutyrate, or both, initiates molecular changes that can be monitored by a specific decrease in absorbance at 267 nanometers. This change in absorbance appears to be associated with a change in macromolecular conformation which is initiated by formation of a complex involving the stimulant molecules.

Alcohols↗
PubMedDate not supplied

An enzymatic method for the analysis of formate in human plasma.

An enzymatic method for the determination of plasma formate concentration is described. Formate dehydrogenase is used to reduce NAD+ to NADH in the presence of formate. The resulting NADH then reduces the dye resazurin to resorufin, a reaction catalyzed by the endogenous diaphorase of the plasma. The generated resorufin is then measured fluorimetrically by exciting it at 565 nm and quantitating the emitted light at 590 nm. The method uses the patient's plasma as the blank and as the matrix for the construction of a patient-specific formate calibration curve. The blank contains all components of the assay system except the formate dehydrogenase. Formate concentration is determined from the calibration curve, constructed by adding known quantities of sodium formate to the plasma base, and plotting the fluorescence intensity against formate concentration. The assay which is sensitive to a formate level of 7 mg/L should find application in cases where formate is a metabolite.

Aldehyde Oxidoreductases↗
PubMedDate not supplied

Three red cell sodium transport systems in hypertensive and normotensive Utah adults.

Sodium-lithium countertransport (SLC), sodium-potassium cotransport (CoT), and ouabain binding to sodium-potassium adenosine triphosphatase (Na, K-ATPase) sites were measured on fresh erythrocytes from hypertensive and normotensive Utah subjects with and without a first-degree relative with hypertension. SLC was measured as Li+ efflux into NaCl and MgCl2 media from Li+-loaded cells (5-7 mM). CoT was measured by monitoring Na+ and K+ efflux from cells loaded to 20-30 mM Na+ and 20-30 mMK+. Ouabain binding was determined for fresh cells using 3H-ouabain. Subjects were selected from pedigrees that showed a prevalence of hypertension. SLC was significantly elevated in 26.5% of the hypertensive subjects (p less than 0.001) as well as in 12.8% of the normotensives with a hypertensive first-degree relative (p less than 0.05). Although elevated SLC and decreased CoT have previously been associated with hypertension, no hypertensive subject in this study exhibited both abnormalities. All subjects with elevated SLC had normal CoT. A positive correlation between SLC and CoT was observed. Few hypertensive subjects (11.8%) had decreased CoT. In the majority of subjects studied, both SLC and CoT were normal: hypertensives 61.8%, normotensives with a hypertensive first-degree relative 61.7%, and other normotensives 58.7%. The number of ouabain-binding sites was not significantly altered among hypertensives, or their relatives, even though there was a positive correlation between SLC and the number of ouabain-binding sites.

Adult↗
PubMedDate not supplied

Inductively coupled plasma mass spectrometry for trace element analysis in the clinical laboratory.

Inductively coupled plasma mass spectrometry (ICP-MS) is a relatively new technique for trace element analysis. The basic operating principles of ICP-MS are described and our experience with this technique in a clinical setting is discussed for the analysis of serum, whole blood, and urine. Advantages to ICP-MS include the favorable detection limits (0.01 to 0.1 micrograms/L for many elements), simple specimen preparation, high throughput (about 40 specimens per hour), and the ability to measure more than one element simultaneously. A major disadvantage is the high capital cost of the instrumentation. Heavier elements, such as lead, are well-suited for ICP-MS analysis, whereas lighter elements are prone to more interferences. Lighter elements which are not amenable to assay by ICP-MS include chromium and iron. The ability to measure isotopes is a major advantage for mass spectrometry methods and has the potential to expand the usefulness of trace element analysis.

Female↗
PubMedDate not supplied

The adequacy of capillary specimens for determining whole blood lead.

In response to demands for reliable alternatives to collection of venous specimens for determination of whole blood lead levels in children, the Centers for Disease Control has called for increased research into capillary methodologies. In this study, a three tiered approach was developed to assess the adequacy of capillary specimens for determining whole blood lead. Patient blood lead results from capillary and venous specimens were compared for obvious differences. Next, follow-up specimens for patients with elevated lead levels were compared with the initial results. In addition, experiments were conducted to determine whether or not handwashing eliminates gross contamination. Although the differences are not clinically important, the mean, 3.83 micrograms/dL for 5,100 venous specimens, was significantly lower (p < 0.005) then the mean of 4.6 micrograms/dL for 1,100 capillary specimens. Gross contamination was rare. Lead levels in follow-up specimens on patients whose initial screens were elevated were generally low. Handwashing greatly reduced the amount of external lead contamination. It is concluded that capillary specimens are an acceptable alternative to venous specimens for whole blood screening programs provided the patient and collector meticulously follow the prescribed collection protocol. Nevertheless, all elevated whole blood lead screening results, venous or capillary, should be confirmed with a venous collection before follow-up action is taken.

Blood Specimen Collection↗
PubMedDate not supplied

Suspected lead poisoning in a public school.

Reports of lead exposure can generate considerable public concern, particularly when children are involved. In December, 1996, a public elementary school in rural Utah was found to have elevated concentrations of lead in its drinking water. The local public health department responded by instituting remediation of the water supply and by warning parents of the possible danger to their children. Subsequent blood lead testing in 116 of the approximately 300 children involved showed an average lead concentration in the range expected for the U.S. population at large. One of the 116 specimens was marginally elevated and was probably unrelated to the school drinking water. Reducing lead exposure is an important public health concern which sometimes generates a response out of proportion to the danger involved.

Adolescent↗