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Biomedical subjects

H Taylor

Publications and source records attributed to H Taylor.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

Calretinin and calbindin-D28K in male rats during postnatal development.

Calcium-binding proteins play potentially important roles in neurogenesis and neuroprotective mechanism(s). Some evidence exists that brain calbindin-D28K (CALB) is regulated by androgens. In the present study, calretinin (CALRET) and CALB patterns were determined by Western analysis in the medial basal hypothalamus (MBH) from male rats along with assaying plasma testosterone levels during postnatal development. Testosterone levels were very low in 7-, 10-, and 30-day-old animals (approximately 0.5 ng/mL), increased in a stair-step fashion to peak levels at 90 days (approximately 3.8 ng/mL), then declined with increasing age to very low levels at 300 days of age (approximately 0.3 ng/mL). At 7 and 10 days, MBH CALRET and CALB levels were low; however, at Day 30 a significant twofold increased was observed. Thereafter, in 60-, 120-, 180-, and 300-day-old animals MBH CALRET and CALB levels were, in general, comparable to 30-day-old values. These findings suggest that there is not a clear correspondence between the androgen status in male rats and the calcium-binding proteins (CALRET & CALB) expressed in the MBH. Therefore, it appears that brain CALRET and CALB are regulated in a developmental fashion with significant increases in expression occurring around the 4th postnatal week.

Aging↗
PubMedDate not supplied

Plant antitumor agents, 27. Isolation, structure, and structure activity relationships of alkaloids from Fagara macrophylla.

The known alkaloids nitidine chloride [1] and 6-oxynitidine [2] and a new compound 6-methoxy-5,6-dihydronitidine [3] have been isolated from Fagara macrophylla. Compound 3 was the major product and was shown to be an artifact. The alkaloids 1 and 3 have been interconverted by treatment of 1 under basic conditions or 3 under acidic conditions. On sublimation 1 and 3 formed 8,9-dimethoxy-2,3-methylenedioxybenzo[c]phenanthridine [4] which could then be converted to 5,6-dihydronitidine [5]. The alkaloids 1 and 3 are about equipotent in P-388 mouse leukemia, giving high T/C values of 240-260% at doses of 30-50 mg/kg. The other compounds were inactive. The structural requirement for antitumor activity in the phenanthridine series is the ability to form a C-6 iminium ion.

Alkaloids↗
PubMedDate not supplied

Indoles in edible members of the Cruciferae.

Antimutagenic fractions from collards yielded indole-3-carboxaldehyde [4] and traces of indole-3-acetonitrile [2]. The compounds had no antimutagenic activity. An analytical procedure for various indoles in plants was developed based on reversed-phase hplc. The indoles studied included the 3-carbinol 1, the acetonitrile 2, the carboxaldehyde 4, the 3-carboxylic acid 5, and the 3-acetic acid 6. Many Cruciferae and non-Cruciferae were analyzed. The latter did not contain measurable quantities of these compounds. In the case of the Cruciferae--with the exception of collards, which consistently indicated the presence of the aldehyde 4--major indole found was the nitrile 2. Although a particularly careful search for the carbinol 1 was conducted, only trace levels were noted. A review of the literature indicates that the content and occurrence of this indole in plants have been heavily overestimated. Because of the low levels found in the Cruciferae, our studies indicate that the role of the compound as a dietary factor may be questionable.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Plant antimutagenic agents, 1. General bioassay and isolation procedures.

An antimutagenic assay in Salmonella typhimurium has been utilized for a study of the inhibition of the mutagenic activity of 2-aminoanthracene in the presence of the Ames S-9 metabolic activation preparation by crude organic solvent extracts of plant materials. More than 2000 extracts representing 39 families have been tested to date. Confirmed inhibitory activity has been found in 80 samples. More than 60% were nontoxic. Methods for isolation and characterization of pure compounds are presented. Of particular interest is the utilization of large scale preparative hplc for rapid purification of inhibitory chromatographic fractions that were still highly impure.

Anthracenes↗