Search PubMed⌕ Search

Biomedical subjects

H Lee

Publications and source records attributed to H Lee.

At least 937 records · Page 52Linked to original sources
PubMed1975

The life cycle of Echinoparyphium ralphaudyi sp. n. (Trematoda: Echinostomatidae).

The life cycel and morphology of Echinoparyphium ralphaudyi sp. n. is described. Natural infections were found in Bulinus truncatus from Egypt, Ethiopia, and the Yemen Arab Republic, and later in B. forskalii and B. sericinus from Ethiopia. Sporocysts develop near the places of miracidial entry into the snail (the head-foot region, mantle edge, pseudobranch, and antennae). Rediae occur mainly in the ovotestis and in tissues anterior to the liver. The first cercariae are released 24 days postexposure. Metacercariae encyst in various freshwater snails and are localized in the pericardial sac and the posterior part of the kidney. Adult worms live in the small intestine of a variety of experimental animals: hamsters, rats, mice, chicks, ducklings, pigeons, and finches.

Animals↗
PubMed1975

Comparative bioavailability of anhydrous griseofulvin and its chloroform solvate in man.

Using a crossover experimental design, the absorption profile of griseofulvin was assessed in human volunteers after oral administration of a 500 mg dose of the antifungal antibiotic as capsules of the anhydrous (nonsolvated)-and monochloroform solvate forms of the drug. The maximum body level of drug and the rate and extent of griseofulvin absorption (or bioavailability) were significantly increased after administration of the chloroform solvate as compared to that observed after administration of the nonsolvated form of the drug. The enhanced absorption of griseofulvin chloroformate correlated well with its enhanced solubility and dissolution rate at 37 degrees C in simulated intestinal fluid (20 mM sodium deoxycholate, pH 7.5). This is the first demonstration of a drug-organic solvate displaying improved gastrointestinal absorption characteristics over the anhydrous form of a drug.

Biological Availability↗
PubMed1974

Inhibition of polypeptide chain initiation in Escherichia coli by elongation factor G.

We have previously reported the isolation from E. coli of a specific inhibitor of polypeptide chain initiation that is rendered ineffective when active aminoacylation of transfer RNA is taking place; this is normally the case during natural messenger RNA translation. Surprisingly, the inhibitory activity appears to be a hitherto unrecognized property of the chain elongation factor G. The following hold for preparations purified for either translocase or inhibitor activity: (1) equal electrophoretic mobility on polyacrylamide gels; (2) equal specific activities for (a) inhibition of initiation, (b) translocation, and (c) ribosome-dependent, uncoupled GTPase; and (3) similar heat sensitivity of translocase and inhibitor activities in a temperature-sensitive E. coli mutant with an altered elongation factor G. Different sites are apparently involved in translocation and inhibition because the former, but not the latter, is sensitive to p-chloromercuribenzoate and fusidic acid.

Acylation↗
PubMed1973

A specific inhibitor of polypeptide-chain initiation in Escherichia coli.

An inhibitor of polypeptide-chain initiation was isolated from E. coli cells. This protein inhibits formation of the 30S or 70S initiation complex with either fMet-tRNA(f) as initiator and AUG, MS2 RNA, or late T4 RNA as messenger, or acPhe-tRNA as initiator and poly(U) as messenger. Chain elongation, e.g., poly(U) translation at high Mg(2+) concentration, is not inhibited. The inhibitor is rendered ineffective when active aminoacylation of tRNA is taking place, e.g., during natural mRNA translation. This inhibitor is distinct from the so-called interference (i) factors, which interfere exclusively with the action of initiation factor 3. Since the new inhibitor can apparently be turned on and off, it may have a regulatory function in translation.

Bacterial Proteins↗