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J A Meyers

Publications and source records attributed to J A Meyers.

10 recordsLinked to original sources
PubMed1993

The structural identification of a methyl analog of methaqualone via 2-dimensional NMR techniques.

A submission to the Drug Enforcement Administration North Central Laboratory of a substance believed to be a structural analog of methaqualone hydrochloride precipitated an interest in being able to obtain a rapid and positive identification of such compounds. Both mass spectrometry and proton NMR spectroscopy (1-dimensional) provided evidence to suggest that the structural analog possessed a second methyl group in the molecule, relative to methaqualone, and that the methyl group was attached to the existing methyl-substituted phenyl ring. By application of proton 2-dimensional (2-D) NMR techniques, specifically the homonuclear shift correlation spectroscopy (COSY) and 2-D NOE (NOESY), the precise location of the methyl group in this unknown methaqualone analog was established and shown to have the structure 2.

Magnetic Resonance Spectroscopy↗
PubMed1986

Assessment of leukocyte alkaline phosphatase by image analysis.

We have shown that it is possible to automate the assessment of leukocyte alkaline phosphatase by using an azo dye cytochemical staining procedure and a commercial, highly sophisticated image analysis instrument originally designed specifically as a differential white cell counter. The data to date indicate that values obtained by this approach are at least as precise and accurate as current manual techniques. Instrumental analysis avoids the subjectivity associated with manual interpretation of staining intensity and should permit meaningful interlaboratory comparisons. The stability of the stained smears upon exposure to immersion oil or Polymount mounting medium proved to be an unexpected bonus. In addition to such functional data on leukocytes as illustrated by this report, these instruments, with appropriate staining methods and software, can also provide clinically useful quantitative data on red cells, as have been described for reticulocytes. We hope to see more clinical applications in the future for these expensive and target-oriented image analysis instruments. They are capable of automatically providing objective quantitative information on a cell by cell basis--providing feature data that cannot be obtained by other means.

Alkaline Phosphatase↗
PubMed1985

The isolation and identification of precursors and reaction products in the clandestine manufacture of methaqualone and mecloqualone.

Abuse of the hypnotic quinazolinone is well recognized and increasing. Clandestine laboratories producing methaqualone (2-methyl-3-ortho-tolyl-4(3H) quinazolinone) and mecloqualone (2-methyl-3-ortho-chlorophenyl-4(3H) quinazolinone) have been discovered throughout the United States. These laboratories utilize one of many synthesis routes to produce the illicit quinazolinone. Frequently, the clandestine chemist has little, if any, formal education in chemistry; does not keep notes; and does not label flasks and beakers containing solutions. The forensic chemist may be asked to analyze unmarked reaction mixtures that were seized in a clandestine laboratory raid. As a result, a rapid method of isolation and identification of the precursors and products of such a mixture is presented.

Chromatography, Gas↗
PubMed1979

Nerve growth factor in medullary carcinoma of the thyroid.

In a case of medullary carcinoma of the thyroid gland assay was performed for nerve growth factor bioactivity. The tumor extract showed significant amounts of nerve growth factor bioactivity, but extracts of normal thyroid and other types of thyroid neoplasms showed no such bioactivity. Nerve growth factor may be useful as a tumor marker in the diagnosis and management of medullary carcinoma of the thyroid. It may play a role in the development of associated tumors of neural crest origin and may contribute to the development of cachexia in patients with medullary carcinoma of the thyroid.

Adult↗
PubMed1979

Restriction of resistance transfer in Staphylococcus aureus.

The transduction frequency of wild type resistance plasmids carrying the modification of a defined donor strain into a series of acceptor strains with different restriction systems and into restriction-deficient mutants was studied. Plasmids carrying resistance to tetracycline, chloramphenicol and penicillin were in general as sensitive as the transducing phage to restriction and modification. Plasmids carrying penicillinase of type A and C could be transferred into strains of group II.

Chloramphenicol↗
PubMed1976

Relationship of bacteriophages to alpha toxin production in Clostridium novyi types A and B.

The relationship of specific bacteriophages to the production of the lethal alpha toxin in Clostridium novyi types A and B was investigated. When type A strain 5771 reverted to the phage-sensitive state, it ceased to produce alpha toxin but continued to produce the gamma and epsilon antigens. This "nontoxigenic" culture, therefore, more closely resembled C. botulinum types C and D than the other C. novyi types. Phage-sensitive type B strains also ceased to produce the alpha toxin but continued to produce the beta toxin, and therefore very colesly resembled C. novyi type D (C. haemolyticum). Alpha toxin was again produced when the phage-sensitive cultures were reinfected with the respective tox+ phages. Alpha toxin production could also be induced in the "nontoxigenic" phage-sensitive derivatives from type B strain 8024 by tox+ phages isolated from other strains of type B. tox- phages were also isolated, but they did not affect alpha toxin production. The tox+ phages also caused a marked change in the colonial morphology of type B strains. In this report we present evidence that alpha toxin production by C. novyi type A strain 5771 and type B strain 8024 depends upon the continued presence and participation of specific bacteriophages designated as NA1tox+ and NB1tox+, respectively.

Antibodies, Viral↗
PubMed1976

Simple agarose gel electrophoretic method for the identification and characterization of plasmid deoxyribonucleic acid.

Agarose gel electrophoresis may be employed effectively for the detection and preliminary characterization of plasmid deoxyribonucleic acid (DNA) present in clinical isolates and laboratory strains of gram-negative microorganisms. The method is sensitive and does not require radioisotopes or ultracentrifugation. The estimation of plasmid mass from the extent of DNA migration in gels compares favorably with results obtained by electron microscopy of plasmid DNA purified by equilibrium density centrifugation. The method has proved to be a useful tool for survey work and the epidemiological investigation of plasmid dissemination, as well as an important adjunct to the genetic analysis of plasmids.

Bacteriological Techniques↗
PubMed1974

Interspecies conversion of Clostridium botulinum type C to Clostridium novyi type A by bacteriophage.

When Clostridium botulinum type C is cured of its prophage it simultaneously ceases to produce toxin. This nontoxigenic culture can then be converted to another toxigenic bacterial species, Clostridium novyi type A or to toxigenic Clostridium botulinum types C or D, by specific bacteriophages. The toxigenicity and type of toxin produced by these cultures depends upon the continued presence of these bacteriophages.

Bacteriophages↗
PubMedDate not supplied

Mammography.

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Breast Neoplasms↗