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Laboratory diagnosis of group A streptococcal infections

Weanling and adult rats injected with one of three concentrations of lead acetate for 37 days failed to demonstrate any learning impairments as measured by a Hebb-Williams maze series relative to water injected controls. Rats at the highest dose level showed clear symptoms of lead poisoning. Pregnant females injected during pregnancy with an asymptomatic dose of lead acetate showed a 100% abortion rate, while 75% of water injected controls delivered litters. Rats whose mothers were injected with asymptomatic doses of lead acetate throughout nursing developed more slowly, weighed less, and demonstrated learning deficits relative to controls. The behavioral and physiological effects of lead may be greatest during the earliest developmental stages.

Learning deficits in lead-injected rats☆

Publisher Summary This chapter discusses the phenomenon of biochemical interference, the role of sample quality on the analysis, and the effect of biological variation in the reported values. Serum or plasma, prepared with various anticoagulants, are used in clinical chemical analysis. The isoenzymes of 6-phosphogluconate dehydrogenase that are determined by electrophoresis on starch gel, but not on agarose, differ according to the anticoagulant used for collecting blood. Many constituents—such as magnesium, potassium, phosphorus, and enzymes—are present in the formed elements of blood, in concentrations many times higher than in the surrounding plasma. Thus, the lysis of cells can contaminate the plasma or serum to a measurable amount. The red cells can release material that interferes in the analytical procedure by contributing color to the reaction, as occurs in the biuret determination of protein, or direct interference in a chemical reaction, as in uric acid assays, which depend on phosphotungstate reduction.

Interferences in diagnostic biochemical procedures.

The localization of dipicolinic acid in dormant spores of Bacillus subtilis was examined by an immunoelectron microscopy method with colloidal gold-immunoglobulin G complex. The colloidal gold particles were distributed mainly in the core regions of dormant spores and were not observed in those of germinated or autoclaved spores. This result clearly demonstrates that dipicolinic acid is localized in the cores of dormant spores.

Ultrastructural localization of dipicolinic acid in dormant spores of Bacillus subtilis by immunoelectron microscopy with colloidal gold particles.

Automated analysis of delta-aminolaevulinic acid in urine.

The addition of yeast extract and the use of shaking increase cell crop yield of group A streptococci grown in Todd-Hewitt broth 4 to 5 times that normally obtained.

https://aem.asm.org/content/aem/18/5/954.full.pdf

Improved growth medium for group A streptococci.

The effect of light exposure and temperature on urinary δ-aminolevulinic acid recovery was studied. Addition of tartaric acid and storage of urine specimens in the dark results in excellent recovery of δ-aminolevulinic acid, even after several days at room temperature. Proper handling and storage of urine collected during surveys of lead poisoning are emphasized.

The Preservation of Urine Specimens for δ-Aminolevulinic Acid Determination

The Measurement of Urinary Delta-aminolevulinic Acid in Detection of Childhood Lead Poisoning

An immunological precipitation system, with rabbit dipicolinyl antibody, was developed for the purpose of evaluating the role of spore dipicolinic acid as a specific haptenic determinant.

Production of antibody against conjugated dipicolinic acid (2,6 pyridine dicarboxylic acid).

CLINICAL CHEMISTRY, Vol. 18, No. 11, 1972 1441 proteins form insoluble complexes with hepanin in the Ca2, was previously published in this journal [CLIN. CHEM. 17,994 (1971)]. In this method the samples were first run and allowed to mix with heparin reagent and then rerun and allowed to mix with a reagent blank that did not contain hepanin. The manifold has been modified (Figure 1) and the sample is allowed to mix simultaneously with both reagents (hepanin and blank) and the turbidities obtained were simultaneously recorded in a double-pen recorder (Figure 2). The obvious advantage of the modification is the time saved, since samples can be processed now (including blanks) at a rate of 70 per hour.

William F. Vincent

Papers

Improved growth medium for group A streptococci.

The Preservation of Urine Specimens for δ-Aminolevulinic Acid Determination

The Measurement of Urinary Delta-aminolevulinic Acid in Detection of Childhood Lead Poisoning

Production of antibody against conjugated dipicolinic acid (2,6 pyridine dicarboxylic acid).

Sickle cell anemia: a suggested screening procedure.