Biomedical subjects

T J Lott

Publications and source records attributed to T J Lott.

22 records · Page 2Linked to original sources

PubMed1985

Computer-aided construction of nucleic acid restriction maps using defined vectors.

A new algorithm is described that will rapidly produce restriction maps of cloned DNA fragments. Information concerning the vector is stored as a data file and used in constructing probable maps. As the program is based upon a permutation analysis it has two primary uses. First, preliminary restriction maps can be created from fragment length data as a starting point for further analysis. Second, existing maps can be confirmed as being highly probable, and other probable maps examined to ensure certain combinations have not been overlooked. Although primarily designed for linear vectors, the program can be used to calculate circular maps.

Algorithms↗

PubMed1985

The use of microcomputers for the quantitation of light intensity patterns using digitized video signals.

We have developed an inexpensive yet versatile microcomputer-based system for quantitating light intensity levels in autoradiographs. This system employs a standard video camera interfaced to an analog-to-digital convertor. A program has been written for this system which can measure intensities within a defined region of an autoradiograph, permitting an easy and accurate quantitation of spots or bands of irregular shape.

Algorithms↗

PubMed1978

Potentiation by 2'-deoxycoformycin of the inhibitory effect by 3'-deoxyadenosine (cordycepin) on nuclear RNA synthesis in L1210 cells in vitro.

The effect of the adenosine deaminase inhibitor, 2'-deoxycoformycin, on the inhibitory effect of cordycepin on nuclear RNA synthesis was examined in L1210 cells in vitro. The median inhibitory dose for the effect of deoxycoformycin on adenosine deaminase was 4 X 10(-8) M, and 100% inhibition was achieved at 5 X 10(-7) M. Pretreatment of cells for 30 min with 1 X 10(-6) M deoxycoformycin resulted in a reduction of the median inhibitory dose for cordycepin from 2.5 X 10(-4) to 1.8 X 10(-5) M, as assessed by the measurement of [3H]uridine incorporation into total RNA. Measurement of the synthesis of nuclear ribosomal RNA, nonpolyadenylic acid heterogeneous RNA, and polyadenylic acid heterogeneous RNA revealed potentiation by 2'-deoxycoformycin of the inhibitory effect of cordycepin on all species of RNA, as well as on polyadenylic acid synthesis. No differences were noted in the size of nuclear polyadenylic acid obtained from cells treated with cordycepin in either the presence or the absence of the adenosine deaminase inhibitor. These results suggest that the potentiation by 2'-deoxycoformycin of the cytotoxic and antitumor effects of cordycepin on L1210 cells in vivo is related to inhibition of nuclear RNA synthesis.

Adenosine Deaminase Inhibitors↗

PubMedDate not supplied

Genomic heterogeneity in the yeast Candida parapsilosis.

Candida parapsilosis shows a wide intraspecies variation in chromosome/homolog size distribution. As a prerequisite for delineating modes of transmission, we have undertaken an analysis of genetic variation at different levels. In the present study we have observed that a majority of isolates display similar electrophoretic karyotype patterns consistent for the species, with variations in the smaller group of chromosomes. In two strains we observed phenotypic "switching"; one of these also exhibited a mixed karyotypic subpopulation. In contrast, a few isolates displayed a greater degree of chromosome/homolog size variation. We also observed, through randomly amplified polymorphic DNA (RAPD) analysis, results consistent with those of pulsed-field electrophoresis. Isolates displaying a high degree of chromosome/homolog variation also displayed a high degree of variation in genomic "fingerprints". Polymorphisms, although present, were much reduced in the majority of isolates. These parallel observations suggest a common underlying mechanism. Our results are consistent with the hypothesis that chromosome-sized variations in C. parapsilosis are due to random genetic events. A similar mechanism has been hypothesized for the taxonomically related yeast Candida albicans.

Base Sequence↗