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Biomedical subjects

J Savory

Publications and source records attributed to J Savory.

At least 127 records · Page 7Linked to original sources
PubMed1980

Rapid centrifugal analyzer enzyme immunoassays for phenytoin, phenobarbital, and primidone.

The adaptation of the homogeneous enzyme immunoassays (EMIT) for phenytoin, phenobarbital, and primidone to a centrifugal analyzer is described. The sample volume required was 10 microliter, and the assay had the capacity to analyze sera from 28 patients within 180 sec. The assay temperature was 30 C, and absorbance was monitored at 340 nm. Coefficients of variation for within-day precision ranged from 2.1% to 3.7%, and analytic recovery was quantitative. The centrifugal analyzer EMIT assay results correlated well with those obtained using high-pressure liquid and gas-liquid chromatographic technics. A logit-log transformation of the absorbance rate versus concentration data was obtained using a modified Gauss-Newtonian nonlinear least-squares fit analysis. Severe hemolysis and lipemia caused interference.

Computers↗
PubMed1980

Serum parathyroid hormone concentrations in senile dementia (Alzheimer's disease).

The accumulation of aluminum in the cerebral cortex has been implicated as a factor in the pathogenesis of Alzheimer type senile dementia (SD) and in the dialysis dementia found in patients with chronic renal failure on long-term intermittent hemodialysis treatment. In animal studies, parathyroid hormone (PTH) produces increased absorption of aluminum from the gastrointestinal tract and elevations of aluminum in the cerebral cortex. It has been proposed that PTH elevations may increase tissue aluminum loads in patients with senile dementia. The present study was undertaken to investigate the status of circulating PTH in patients with SD and age/sex matched controls. No significant differences were found between these groups. Elevated PTH (when it did occur) seemed to be related to the degree of renal impairment rather than dementia. Differences in the distribution of aluminum in patients with dialysis dementia and SD are discussed.

Aged↗
PubMed1980

Radioimmunoassay of human pancreatic amylase in serum and urine.

The purification of human pancreatic amylase (EC 3.2.1.1) and the development of a radioimmunoassay for this enzyme is described. The enzyme was purified from a normal pancreas obtained at autopsy and antibodies were produced in rabbits. The purified pancreatic amylase was radioiodinated and the radioimmunassay was developed. Analytic recoveries in serum and urine specimens were 99 and 96%, respectively, and day-to-day precision was less than 10%. The assay gave a 20% cross-reactivity with salivary amylase.

Amylases↗
PubMed1980

Automated multiple flow-injection analysis in clinical chemistry: determination of albumin with bromcresol green.

We describe an adaptation of automated multiple flow-injection analysis instrumentation to an analysis for albumin in serum. The bromcresol green reaction was used to test the utility of the system. The approach yielded albumin results with excellent sensitivity, no measurable carryover, a relative standard deviation of less than 1%, good correlations with published procedures, and no measurable interferences. The simplicity and flexibility of the instrumentation and its performance integrity, as indicated by the analytical results, make this a viable clinical chemical tool.

Bromcresol Green↗
PubMed1980

Clearance of [14C] polyamines from plasma and erythrocytes in the rat.

The [14C] polyamines, putrescine, spermidine and spermine were administered intravenously to rats. Arterial blood samples were obtained 2, 4, 6, 12, 20, 30, 60 and 120 min. after injection. Plasma and erythrocyte fractions were separated and assayed for [14C] activity. The clearance of radiolabelled polyamines from both the plasma and erythrocytes was rapid. Within 10 min. of injection, plasma putrescine had decreased by 70%, spermine by 80% and spermidine by 85%. In the same time interval the erythrocyte putrescine level had decreased by 50%, spermine by 70% and spermidine by 80%. This data suggests that exogenously injected radiolabelled polyamines and presumably endogenously produced polyamines are rapidly cleared from the circulation.

Animals↗
PubMed1980

Erythrocyte polyamine levels in rats with H4IIE hepatomas before and after radiation treatment.

The concentration of the polyamines, spermidine and spermine associated with the erythrocytes of rats with H-4-II-E hepatomas increased with tumor growth. Following radiation therapy the erythrocyte spermidine and spermine levels decreased by 63 and 47% respectively. Six days after radiation treatment the erythrocyte polyamines had increased to the pre-treatment elevated levels. These data suggest that erythrocyte polyamine levels may be useful in assessing the response to therapy and in detecting the continued growth of the tumor in patients with malignant disease.

Animals↗
PubMed1980

Automated multiple flow-injection analysis in clinical chemistry: determination of total protein with Biuret reagent.

We have examined the feasibility of the automated multiple flow-injection technique for application to clinical chemistry by adapting to this system the biuret method for the determination of total protein. Samples were discretely and rapidly introduced into a continuously flowing, nonsegmented reagent stream by means of an automatic sampler and high-pressure injection valve. Pumps operating at 1380-2070 kPa (200-300 psi) were utilized to introduce the biuret reagent and saline diluent into the system separately at flow rates of 72 and 47 microL/s, respectively. Use of 20-microL sample and a 3.0-s reaction-delay coil was adequately sensitive for analysis for total protein by this method. Samples were analyzed at a rate of 150/h with no detectable between-sample carryover. Within-run precision studies yielded relative standard deviations of 2.5% and less. Total protein values obtained by this method correlated well with those obtained by centrifugal analyzer and bubble-segmented continuous-flow biuret methods.

Autoanalysis↗
PubMed1979

Effects of hemodialysis on protein-bound calcium.

This study evaluates whether hemodialysis alters the affinity of plasma proteins for calcium. We have used a new automated methodology for the determination of the dialyzable calcium fraction. Protein-bound calcium was estimated as the difference between the total and dialyzable calcium fractions. All measurements were made after adjustment of the sample pH to 7.40 +/- 0.02. The calcium fractions were determined in 12 patients before and after hemodialysis. In addition, we added calcium to the predialysis specimens to evaluate the effect of increased ionic calcium on protein binding and corrected the protein-bound calcium in these specimens for the increase in total protein observed in the postdialysis specimens. Hemodialysis significantly increased total, dialysable, and protein-bound calcium. The mean ratio of protein-bound calcium in the postdialysis specimens to the corrected protein-bound calcium in the predialysis specimens with calcium added was 0.97 +/- 0.02. We conclude that (1) the increase in protein-bound calcium to the predialysis specimens, and that (2) the binding affinity of serum proteins for calcium is not altered by hemodialysis.

Blood Proteins↗
PubMed1979

Enzyme immunoassay of carbamazepine with a centrifugal analyzer.

We describe a rapid enzyme immunoassay for carbamazepine with a centrifugal analyzer (Rotochem IIA-36). Reagent costs are reduced fourfold while good precision and sensitivity are maintained. Sample volume is 10 microliter, and as many as 28 patients' sera can be measured during an assay time of 225 s. Assay temperature is 30 degrees C, the wavelength 340 nn. Linearity is excellent for a carbamazepine concentration range of 1 to 12 mg/L; analytical recovery is quantitative. Results correlate well with those by liquid- and gas-liquid chromatography. Absorbance rates for each carbamazepine concentration are acquired by a multi-point kinetic rate program and a computer program provides a logit-log transformation of absorbance rate vs. concentration data for final calculations in the assay. Hemoglobin interference precludes analysis of severely hemolyzed specimens.

Carbamazepine↗
PubMed1979

Performance assessment of the GammafloTM automated radioimmunoassay system by assaying for digoxin.

We report an evaluation of the GammafloTM automated continuous-flow radioimmunoassay instrument in which we used a digoxin assay to assess system performance. System operation was based on combined continuous-flow and column-chromatographic techniques. No drift or carryover was detectable in 180 within-assay consecutive determinations performed at a rate of 42 determinations per hour (5 h of continuous operation). Within-assay and between-assay precision were less than 6% (coefficient of variation). The automated method correlated well (r = 0.960 and 0.952, respectively) with two established manual digoxin radioimmunoassay procedures. The data suggest this automated system offers a valid alternative to manual radioimmunoassay procedures in terms of overall precision, simplicity of operation, and sample throughout capacity.

Autoanalysis↗
PubMed1979

Plasma polyamines determined by negative-ion chemical ionization/mass spectrometry.

We have developed an accurate and highly sensitive gas-chromatographic/mass-spectrometric procedure for determining di- and polyamines (putrescine, spermidine, and spermine) in plasma and erythrocytes. Deuterium-labeled analogs of putrescine, spermidine, and spermine were synthesized for use as internal standards. Trifluoroacetyl derivatives of the polyamines were formed during the procedure and then detected with negative-ion chemical ionization/mass spectrometry in combination with multiple ion monitoring. Limits of sensitivity ranged from 0.25 to 1.0 pmol of analyte injected into the instrument.

Chromatography, Gas↗
PubMed1979

Immunonephelometric assay for urinary total protein and albumin in mice.

A quantitative immunonephelometric assay for measuring total protein and albumin in mouse urine has been developed. Antisera to whole mouse sera or to mouse albumin was added to aliquots of urine and the antigen-antibody complexes formed were measured by laser nephelometry. Sample volumes were small (20 microliters) and the assay time was 90 minutes. The assays were sensitive to 10 mg/L and within-day and day-to-day precision studies demonstrated coefficients of variation of less than 15%. Average urinary total protein and albumin concentrations for random urine specimens in female C3H mice (age 80-150 days) were 42 and 24 mg/L respectively. Urinary total protein and albumin to creatinine ratios were also determined.

Albuminuria↗
PubMed1979

Serum binding of aluminum.

The binding of aluminum in the serum of a normal male volunteer was examined using gel filtration chromatography and flameless atomic absorption spectrometry. The elution profile obtained with Sephacryl S-200 gel separated the aluminum into four major peaks. These peaks appear to be associated with a high molecular weight protein(s), albumin, and possibly some low molecular weight protein(s) and/or some inorganic anions. The elution profile for a renal dialysis patient gave similar results.

Adult↗
PubMed1979

Centrifugal analyzer method for total bilirubin in serum by use of diazotized 2-chloroaniline-5-sulfonic acid.

We describe two centrifugal analyzer methods for measuring total bilirubin in serum. Diazotized 2-chloroaniline-5-sulfonic acid is used in both. In the first procedure, ethylene glycol and methanol are used as an accelerator solvent; results correlate well with those by a Jendrassik and Grof method adapted to the centrifugal analyzer, but there is considerable hemolysis interference. In the second method, dimethyl sulfoxide is used with the ethylene glycol/methanol solvent and almost all hemolysis interference is eliminated. For either method, a 15-microliter sample is required. In the second method, instrument response is linearly related to concentration to 250 mg/L and the within-run precision (CV) is about 1%.

Azo Compounds↗
PubMed1978

The influence of residual factor VII on the sensitivity of brain thromboplastin.

One-stage prothrombin times of normal and of factor VII-deficient beagle plasma were determined with two types of beagle brain thromboplastin, one prepared from normal beagles and the other from factor VII-deficient beagles. There was little difference between the reagents in the prothrombin times obtained for normal plasma. However, when factor VII-deficient plasma was tested, reagent prepared from factor VII-deficient beagles gave considerably longer prothrombin times than were obtained with the normal reagent and the difference increased with increasing reagent concentration to a maximum at 140 mg/ml. Prothrombin times of a series of mixtures of normal and factor VII-deficient plasma indicated that the presence of only 1/90 part of normal plasma was necessary to compensate for the difference between the two reagents. Determination of the iron content of the reagent suggested that the microcirculation of an average brain contained some 1.8 g of whole blood. The finding that brain thromboplastin prepared from factor VII-deficient beagles is more sensitive to a deficiency of factor VII in plasma, presumably a result of the smaller quantity of factor VII present in the reagent, is compatible with the known kinetics of extrinsic coagulation.

Animals↗
PubMed1978

Evaluation of an aqueous fluorometric continuous-flow method for measurement of total urinary estrogens.

Measurement of urinary estrogen excretion is used extensively to monitor fetal welfare in utero, allowing the fetus at risk to be identified. We evaluated a direct all-aqueous fluorometric method adapted to a continous-flow (AutoAnalyzer I) system, using a spectrofluorophotometer for detection. In this method, which is based on a modified Kober reaction, NaBH4 is used to eliminate the known negative interference of glucose. The mean analytical recovery was 98%. Urines from 15 men showed no blank fluorescence. Comparison studies of the fluorometric method (x) and a manual method based on the Kober/Ittrich reaction (y) yielded the equation y = 1.53x + 4.38 (r = 0.9235). The incomplete correlation can be explained by erratic extraction in the manual Kober/Ittrich procedure (mean recoveries were 57%). A day-to-day precision (CV) of 5.2% can be achieved with the automated method. Samples are analyzed at a rate of 20 per hour, but this rate can be doubled, if necessary, without significant carryover problems. We conclude that the automated fluorometric method is accurate, precise, and inexpensive and therefore the method of choice for measuring urinary estrogens.

Autoanalysis↗