Biomedical subjects

D L Cheo

Publications and source records attributed to D L Cheo.

21 records · Page 2Linked to original sources

PubMed1989

Intraocular penetration of cytosine arabinoside following subconjunctival administration in primates.

Cytosine arabinoside was administered subconjunctivally to three monkeys. Blood, aqueous, and vitreous specimens were collected after 30 minutes, 1 hour, 2 hours, and 3 hours. Intraocular drug concentrations appeared stable or increasing over this time period while intravenous levels were relatively low. The results of this study suggest that therapeutic intraocular concentrations of cytosine arabinoside are obtained following subconjunctival administration in primates with lower, nontoxic intravenous levels during this time.

Animals↗

PubMed1988

Intraocular penetration of cytosine arabinoside following intravenous administration in primates.

Cytosine arabinoside was administered intravenously to three monkeys. Blood, aqueous, and vitreous specimens were collected after 30 minutes, 1 hour, 2 hours, and 3 hours. Intraocular and intravenous drug concentrations were comparable at all time points, at levels likely to be effective against human tumors. This study suggests that therapeutic intraocular concentrations of cytosine arabinoside are attained following intravenous administration in primates.

Animals↗

PubMedDate not supplied

Molecular characterization of regulatory elements controlling expression of the Bacillus subtilis recA+ gene.

Expression of the Bacillus subtilis recA gene is induced following DNA damage as well as during the development of the competent state. DNA damage-induction of the recA gene occurs by a RecA-dependent mechanism, whereas competence-induction occurs by a RecA-independent mechanism. To examine the molecular mechanisms that control the expression of the recA gene, a deletion analysis of the recA promoter region was performed. A regulatory region that is required for repression of recA expression was identified upstream of the recA promoter. Deletion of this regulatory region derepressed expression and abolished damage-induction of the recA promoter. Within this region are sequences similar to the consensus sequence that has been identified within DNA damage-inducible promoter regions of other B subtilis genes. Another regulatory region was identified that is required for the RecA-independent, competence-specific induction of the recA gene. Deletion of these sequences significantly reduced competence-induction of the recA promoter.

Amino Acid Sequence↗