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Biomedical subjects

R J Elin

Publications and source records attributed to R J Elin.

At least 145 records · Page 8Linked to original sources
PubMed1983

Mechanism of cefoxitin and cephalothin interference with the Jaffé method for creatinine.

Some cepha antibiotics interfere positively in the Jaffé method for determining creatinine. The extent of this interference differs with the modification used, and its mechanism is unknown. We studied the spectrophotometric and thermodynamic properties of the reaction of picrate with creatinine and two cepha antibiotics, cefoxitin and cephalothin. The absorbance spectra of the chromophore produced by each of the three compounds when reacted with picrate were essentially identical, with an absorbance maximum at 485 nm. We determined the molar absorptivity, rate constant, and equilibrium constant for the reaction of the three compounds with picrate. The molar absorptivity was similar for creatinine and cefoxitin but about fourfold smaller for cephalothin. The rate constant and equilibrium constant for the reaction with picrate were respectively 20- and 10-fold greater for creatinine than for either of the two cepha antibiotics. Thus, these differences indicate the mechanism by which these two cepha antibiotics interfere with the Jaffé procedure for creatinine, and explain why the degree of interference depends on details of the procedure.

Autoanalysis↗
PubMed1982

Serum total and isoenzyme lactate dehydrogenase activity in American Burkitt's lymphoma patients.

Serum total lactate dehydrogenase (LDH) and LDH isoenzyme activities were studied in 45 American patients with a tissue diagnosis of Burkitt's lymphoma. Serum total LDH activity correlated with tumor burden as determined by clinical staging at presentation or clinical stage of the disease process ("disease status"). Tumor lysis by chemotherapy considerably increased the serum total LDH activity. For the LDH isoenzyme pattern, the largest relative increases were found with LDH3 and LDH4, whereas the highest isoenzyme activities occurred with LDH2 and LDH3. Thus, the total and isoenzyme LDH activities are helpful to evaluate the tumor burden and prognosis in patients with Burkitt's lymphoma.

Adolescent↗
PubMed1982

Workload, space, and personnel of clinical chemistry laboratories in teaching hospitals.

The resources needed to operate a clinical chemistry laboratory are known only as rough approximations. In order to gather more information about these resources, a 13-page questionnaire was completed by 50 pathology departments of which 38 departments provided adequate information about their clinical chemistry section to permit adequate data analysis. This study provides the results for resource and workload factors, and significant regression analyses among these factors for the whole clinical chemistry section and the subsections of general chemistry, urinalysis, endocrinology, enzymology, lipid analysis, and toxicology. These data provide a basis for evaluating the current needs of clinical chemistry and for making projections for the future.

Chemistry, Clinical↗
PubMed1982

Incidence of gamma-globulin banding in a healthy population by high-resolution electrophoresis.

We report the incidence of electrophoretically homogeneous protein bands occurring in the gamma-globulin region in serum samples from 600 healthy adults, as determined with a high-resolution electrophoretic system. One or more electrophoretically homogeneous protein bands of various intensities were detected in the gamma-globulin region of 30 specimens when we used an improved agarose electrophoretic system, and in two specimens when we used a cellulose acetate electrophoretic system. Improvement of the agarose gel electrophoretic system thus enhanced its sensitivity in defining homogeneous protein bands in the gamma-globulin region. The incidence of these bands in a healthy population is approximately 5%.

Adult↗
PubMed1982

Quantification of acute phase reactants after muscle biopsy.

Blood concentrations of six acute phase reactants (ESR, neutrophil count, fibrinogen, haptoglobin, alpha 1-antitrypsin, and ferritin), parameters of muscle necrosis (myoglobin, CK, ALT, and AST) as well as hemopexin, iron, and TIBC were determined before and for 7 consecutive days after muscle biopsy in patients and in a control group. A muscle biopsy was chosen as a standardized surgical procedure that induces a mild transient inflammatory response. After muscle biopsy, a significant increase occurred in five (ESR, neutrophil count, fibrinogen, haptoglobin, and alpha 1-antitrypsin) of the six acute phase reactants. The concentration of serum ferritin did not show a significant change. A significant decrease was noted in the serum iron concentration and a significant increase occurred with CK and myoglobin secondary to the muscle biopsy. Thus the inflammation of a muscle biopsy produces a significant acute phase reaction.

Adult↗
PubMed1982

Four methods for determining uric acid compared with a candidate reference method.

Uric acid as measured in serum by three different uricase (EC 1.7.3.3) methods (aca, Ektachem, and SMAC) and by the SMAC method with phosphotungstic acid was compared with a candidate Reference Method for uric acid. Serum specimens from 83 patients (uric acid concentrations, 19 to 141 mg/L) were analyzed by all five methods. Results were compared by using linear regression analysis, and the mean difference between results by the candidate Reference Method and the four other methods was calculated. Compared with the candidate Reference Method, the aca method gave the smallest deviation from zero for the intercept and the smallest mean difference, and the SMAC phosphotungstic acid method showed a slope closest to unity. The SMAC uricase method had the largest intercept and greatest deviation of the slope from unity.

Autoanalysis↗
PubMed1982

Lactate dehydrogenase activity as measured by the SMAC is related to flow-cell energy.

Determination of lactate dehydrogenase (LDH) activity in the SMAC (Technicon) is based on the change in NADH absorbance between two flow cells. We noted that results for patients' specimens and controls changed when the fiber optic terminations for the two LDH channel flow cells were adjusted or "peaked" at the colorimeter chopper assembly. The energy (intensity) of light reaching the flow cells was varied by adjusting the fiber optic terminations, and the absorbance readings for a series of solutions containing NADH and patients' specimens were recorded. For both flow cells, when the fiber optic terminations were adjusted to increase the zero absorbance light intensity from 20 lines to 60 lines, a significant (p less than 0.0001) proportional change was seen in the absorbance readings. Evidently the difference in absorbance between the two flow cells is related not only to the NADH concentrations but also to the difference in the light intensity at the two flow cells. Consequently, changes in the adjustment of the fiber optic terminations produce systematic changes in results for LDH in patients' sera. These systematic changes in LDH results may be minimized by maintaining equivalent settings of the fiber optic terminations for the two flow cells and by using the calibration material with an absorbance most similar to that of patients' specimens.

Autoanalysis↗
PubMed1981

Departmental resources and statistics of academic pathology.

The resources needed to operate an academic pathology department have not been evaluated for several years. Fifty academic pathology departments in this country returned a 14-page questionnaire that included information about procedures, personnel, space, and patient load. These data were summarized using means, percentiles, ratios, and linear regression analyses. The average academic pathology department performed more than 5,000 procedures for 1,200 inpatients and outpatients per day and produced 42 publications per year. The results of this study may assist members of the academic pathology community in assessing current and future needs.

Pathology↗
PubMed1981

Properties of reference Escherichia coli endotoxin and its phthalylated derivative in humans.

The properties of a reference bacterial endotoxin prepared from Escherichia coli and its phthalylated derivative were studied in normal human volunteers infected intravenously with the compounds. The minimal pyrogenic dose of the reference endotoxin is about 0.1-0.5 ng/kg. The increase in white blood cell count, absolute granulocyte count, absolute immature granulocyte count, and concentrations of serum amyloid A, cortisol, and growth hormone was directly related to the concentration of reference endotoxin administered. Phthalylated reference endotoxin up to 1,000 ng/kg (at least 500 ng of the patent compound/kg) was administered to normal human volunteers without significant changes in temperature, white blood cell count, absolute granulocyte count, and concentrations of serum amyloid A, cortisol, and growth hormone. Thus, this study defines biologic properties of the new reference bacterial endotoxin in humans and demonstrates effective detoxification by phthalylation of the present compound.

Adult↗
PubMed1981

Low results for inorganic phosphorus with the SMAC continuous-flow analyzer.

Serum inorganic phosphorus concentrations as measured with the SMAC are lower than those found with other methods. To resolve this problem we analyzed patients' specimens and performed analytical recovery studies with four different systems (SMAC, AutoAnalyzer II, aca, and the Fiske--SubbaRow method). With the SMAC, results for patients' specimens are significantly lower (p less than 0.0001) than with any of the other three methods. The SMAC recovered only about 87% of the added inorganic phosphorus. The value assigned to SMAC Reference I for inorganic phosphorus was 0.876 of the value obtained when the material was analyzed by the reference method. Thus there is a significant systematic error in the SMAC method for inorganic phosphorus determination, attributable to an erroneous inorganic phosphorus concentration assigned the SMAC calibration material by the supplier (Technicon).

Autoanalysis↗
PubMed1980

Instrumentation in clinical chemistry.

Major advances in instrumentation have revolutionized the clinical chemistry laboratory during the past two decades. This article focuses on some of the more recent developments in instrumentation for clinical chemistry in the areas of general chemistry, immunoassays, urinalysis, electrophoresis, chromatography, and trace metal analyses.

Centrifugation↗
PubMed1980

Comparison of four electrolyte instruments using the proposed NCCLS protocol for evaluation of precision and accuracy of automated instruments.

We compared four instruments, [Sequential Multiple Analyzer Computer (SMAC), AutoAnalyzer II (AAII), StatLyte and PVA-4] for the determination of Na, K, Cl and CO2 using the National Committee for Clinical Laboratory Standard's (NCCLS) protocol (PSEP-1) for evaluation of precision and accuracy of automated instruments. The protocol was applied concurrently to all four instruments. The repeatability results showed SMAC to have the highest precision among-days for K, Cl, and CO2 whereas StatLyte showed the highest precision among-days for Na. The PVA-4 had the best within-run precision for Na and Cl while the AAII and SMAC had the best within-run precision for K and CO2 respectively. Systematic biases among the instruments were small for Na and K. The AAII exhibited a nearly constant bias at all concentrations of Cl relative to the other three instruments. For CO2 the SMAC showed a large proportional bias compared with the other three instruments.

Autoanalysis↗
PubMed1980

Positive Limulus amoebocyte lysate reactions with polyriboinosinic acid x polyribocytidylic acid.

The annealed copolymer polyriboinosinic acid x polyriboinosinic acid reacted with Limulus amoebocyte lysate to cause gelation at a concentration approximately 2,000-fold or greater than bacterial endotoxins. This copolymer was pyrogenic in rabbits and demonstrated hypochromicity, but no significant correlation was noted among Limulus amoebocyte lysate reactivity, progenicity, and hypochromicity. Like endotoxin, polyriboinosinic acid x polyribocytidylic acid did not react with purified Limulus coagulogen. Similar concentrations of the homopolymers polyriboinosinic acid and polyribocytidylic acid were negative or significantly below the Limulus amoebocyte lysate reactivity of the copolymear and essentially nonpyrogenic. Thus, polyriboinosinic acid x polyribocytidylic acid is a compound in addition to endotoxin that effects a positive Limulus amoebocyte lysate test.

Animals↗