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Biomedical subjects

M A Evenson

Publications and source records attributed to M A Evenson.

At least 37 records · Page 2Linked to original sources
PubMed1978

The presence of fatty acids in human alpha-fetoprotein.

alpha-Fetoprotein has been prepared from human fetal tissue by procedures utilizing DEAE-Sephadex, concanavalin A-Sepharose, and isoelectric focusing. A major and a minor component with isoelectric points of 4.7 and 5.3, respectively, have been isolated and are similar to those prepared under various conditions by other investigators. The 4.7 material contains 2.4 mol of fatty acids/mol of protein, whereas the minor component is fat-free. The relative amounts of fatty acid vary somewhat with different preparations. The ranges found in three isolates were as follows: palmitic acid (8 to 11%), stearic acid (2 to 5%), oleic acid (10 to 28%), linoleic acid (7 to 15%), arachidonic acid (12 to 39%), and 4,7,10,13,16,19-docosahexaenoic acid (16 to 42%). Human fetal serum albumin contained 0.7 mol of fatty acid/mol of protein, with arachidonic acid and the docosahexaenoic acid comprising only 11.4% of the total. Removal of fatty acids by treatment with charcoal converted alpha-fetoprotein into material with an isoelectric point of pH 5.3. Addition of arachidonic acid to the lipid-free protein restored it to protein with a pH 4.7 isoelectric point, typical of the major native component. The possible role of the fatty acids in alpha-fetoprotein on the inhibition of various lymphocyte functions is projected.

Chromatography, Gas↗
PubMed1977

Diagnosis and treatment of fat embolism.

Fat emboli syndrome is one of the major causes of early posttraumatic respiratory distress. Careful attention to the multiple factors associated with the early resuscitative period can minimize this lethal complication of multisystem injury. The use of high-dose steroids and appropriate ventilatory support will decrease the high mortality rate associated with this disease syndrome once it has developed.

Adrenal Cortex Hormones↗
PubMed1976

Correction of protein binding defect in uremic sera by charcoal treatment.

Protein binding of numerous drugs, primarily organic acids, is decreased in sera from uremic patients. The defect in binding is (1) greater than can be accounted for by hypoalbuminemia alone; (2) unchanged by prolonged in vitro dialysis; (3) transferred in the protein but not the ultrafiltrate fraction of uremic serum; and (4) not reproduced by addition of low and middle molecular weight compounds known to accumulate in uremia. However, treatment with activated charcoal at pH3 was found to significantly increase drug protein binding in uremic sera. This effect was studied with six different drugs in sera from groups of 6 normal subjects and 8 patients on chronic hemodialysis. The percentage of sulfamethoxazole, dicloxacillin, diphenylhydantoin, salicylate, and digitoxin bound to protein in normal sera (65.9, 97.1, 93.1, 96.7, and 92.7, respectively) was unchanged by charcoal treatment. In contrast, charcoal treatment significantly (p less than 0.01) increased the percentage of drug bound to protein in uremic sera from 41.7 to 59.0 for sulfamethoxazole, 90.7 to 96.3 for dicloxacillin, 84.3 to 90.8 for diphenyhydantoin, 86.4 to 93.8 for salicylate, and 89.5 to 90.9 for digitoxin. Charcoal treatment significantly (p less than 0.05) reduced penicillin protein binding in normal sera and failed to correct the binding defect for penicillin in uremic sera. The effect of charcoal can be explained by removal of an inhibitor which accumulates in uremia and (1) occupies the binding site of certain drugs, (2) changes the configuration of the albumin molecule, or (3) both. Free fatty acid (FFA) concentrations in uremic patients were similar to those in normal subjects and were not the cause of the binding defect.

Blood Proteins↗
PubMed1976

Serum theophylline analysis by high-pressure liquid chromatography.

We have developed and evaluated a rapid, high-pressure liquid-chromatographic method for theophylline in serum. Only 0.2 ml of serum is required for each determination, and the sensitivity of this method is 0.5 mg/liter. This method, involving liquid extraction and silica adsorption chromatography, provides adequate selectivity, accuracy, and precision for routine or research applications. Little sample preparation is required before chromatography. We found no endogenous or exogenous interferences. Use of beta-hydroxypropyl theophylline as the internal standard provides reproducible results for this micro-scale method.

Caffeine↗
PubMed1975

Ultramicro analysis for copper, cadmium, and zinc in human liver tissue by use of atomic absorption spectrophotometry and the heated graphite tube atomizer.

We describe a method of analysis for copper, cadmium, and zinc in a 15-mg (wet weight) sample of human liver by atomic absorption spectrophotometry. The sample is digested with nitric acid (1.0 mol/liter), evaporated, and dilute HNO3 (10 mmol/liter) added. The reconstituted acid mixture is injected into the graphite tube atomizer for analysis of Cu and Cd and aspirated into the air--acetylene flame for measurement of Zn. The absorbance for each metal is suppressed with increasing pH. NaNO3, KNO3, KCl, and NaCl (e.g.) quench the Cd absorbance in acid solutions that contain no protein, but not in the presence of protein. Metal ions added to the predigestion human liver sample at 10 percent and 100 percent of the intrinsic metal concentrations were, respectively, 93 percent and 90 percent accounted for analytically in the case of Cu, 98 percent and 102 percent for Zn, and 101 percent and 93 percent for Cd. Analysis of a National Bureau of Standards' Bovine Liver Standard Reference Material yielded results corresponding to 99 percent (Cu), 112 percent (Zn), and 91 percent (Cd) of the mean expected concentrations of these metals. The between-run coefficient of variation for the bovine liver material was 6 percent for Cu, 9 percent for Zn, and 10 percent for Cd. For 16 histologically normal samples of human liver, the mean values were: Cu, 26; Zn, 293; and Cd, 6.0 nanograms of metal per milligram dry weight, in agreement with values published previously. The method can be easily and reliably applied to small samples of liver obtained by closed-needle biopsy.

Animals↗
PubMed1975

Determination of serum copper by atomic absorption, with use of the graphite cuvette.

We have established and evaluated a flameless graphite cuvette method for copper in serum. This atomic absorption method provides substantial improvement in sensitivity, adequate accuracy, and acceptable precision, and little sample preparation is required before the analysis. Standard addition studies and measurements of National Bureau of Standards materials indicated that the proposed method is accurate, but that sample pH must be kept between 2 and 3 for high accuracy. Cations and anions that frequently are present in protein-containing samples do not interfere significantly. Sample cross contamination in the syringe must be carefully avoided. Finally, when results for more than 100 patients' sera by this method were compared to those obtained by flame atomic absorption for the same samples, no substantial bias or inaccuracies could be attributed to this new micro-scale method for serum copper. Hence, this method is ideally suited for use on pediatric patients.

Copper↗