Biomedical subjects

M R Gross

Publications and source records attributed to M R Gross.

3 recordsLinked to original sources

PubMed1989

Serum 11-ketotestosterone and testosterone concentrations associated with reproduction in male bluegill (Lepomis macrochirus: Centrarchidae).

Male bluegill (Lepomis macrochirus) display a complex reproductive behavior involving two alternative life history pathways: delay of sexual maturation to become "parentals" or precocious maturation as "cuckolders." The purpose of our study was to investigate the association of two androgens, 11-ketotestosterone (11KT) and testosterone (T), with reproduction in these two types of males. Radioimmunoassay techniques were used to measure daily levels of the two androgens in the blood serum of parental male bluegill captured during the prespawning, spawning, and nesting periods throughout the reproductive season. Dramatic changes in the levels of 11KT and T were observed among parental males during these periods. Peaks occurred at the onset of spawning activity during each breeding bout. Compared to spawning parental males, spawning cuckolder males had significantly lower serum levels of 11KT. In contrast, the serum levels of T among parental and cuckolder males were not significantly different. These findings suggest that the elevated levels of 11KT are associated with the behaviors displayed by spawning parental males. The levels of T, however, seem to be associated with the occurrence of a phenomenon common to both parental and cuckolder males, such as development of gonads and/or spermiation.

Animals↗

PubMed1966

Topics in library technology: binding techniques.

The purpose of the library binding industry is to help the librarian maintain a valuable inventory of printed material for maximum use now and in the future. Standardization of approved materials and methods in the industry have encouraged manufacturers to develop materials and machinery for its use, and these, in turn, have enabled it to meet the increasing and changing needs of libraries with a uniform product of high quality and an economical and constantly improving service. The librarian, as custodian of the library's materials, must be the originator of the binding program and is the only one who knows the end use of each item, which is usually the factor that determines the selection of the most suitable binding.

Bookbinding↗

PubMedDate not supplied

An analysis of the spectra of genetic activity produced by known or suspected human carcinogens.

For 24 agents classified by the International Agency for Research on Cancer as known or suspected human carcinogens, we previously catalogued the qualitative genetic bioassay data available in the literature. In the present analysis, dose information, where available, was added to this data base: either the lowest effective dose (LED) or the highest ineffective dose (HID) was recorded for each agent and bioassay system. Bioassay systems were organized according to classes of genetic activity and subdivided by the phylogenetic level of the test organism. For each compound, the quantitative results in the test systems were represented by computer-generated bar graphs ('genetic activity spectra'). The x-axis unit values corresponded to the 100 different test systems, and the y-axis values were the logarithmically transformed LED or HID values. Statistical methods and pattern-recognition techniques were used to evaluate the genetic activity spectra. Spectra were compared among agents grouped according to target-organ specificity. In addition, the spectra of all possible pairs of compounds were compared to identify compounds displaying qualitatively or quantitatively similar genetic activity. Chemically similar compounds frequently produced similar spectra of genetic activity, and it was possible to identify the most appropriate test systems for some classes of compounds. As the data base for human carcinogens is enlarged, analysis of genetic activity spectra may contribute to our understanding of the structure-activity relationships and mechanisms of action of these agents.

Animals↗