PubMed Health⌕ Search

Biomedical subjects

A P Green

Publications and source records attributed to A P Green.

18 recordsLinked to original sources
PubMed1995

HPLC purification of synthetic oligodeoxyribonucleotides containing base- and backbone-modified sequences.

Applications for a new polymer resin, PolyFlo, are described for both the small-scale and large-scale purification of synthetic oligodeoxyribonucleotides varying in length from 18-41 bases. The unique properties of this innovative resin provide > 95% purified full-length oligodeoxyribonucleotides with greater than 90% yield starting from either crude trityl-on or trityl-off unmodified as well as base (biotin)- or backbone (e.g., phosphorothioate)-modified products. Full biological activity of recovered nucleic acid is retained, and the resin is capable of removing contaminating endotoxins during purification. The resin performance is predictable and reliable. The resin can be regenerated easily and is particularly economic when employed directly in ammonia or with the trityl-off option. PolyFlo meets the requirements of current Good Manufacturing Practices.

Ammonium Hydroxide↗
PubMed1993

Structure/function analysis of the Ala116-->Lys121 region of endonuclease V by random targeted mutagenesis.

Endonuclease V is the product of the denV gene of bacteriophage T4 and is responsible for the recognition and repair of pyrimidine dimers due to UV irradiation of DNA. This is accomplished by a two-step mechanism involving incision at the site of the lesion followed by cleavage of the phosphate backbone. In order to better understand this molecule, and to validate our new mutagenesis procedure, we have constructed a series of random mutations within the region Ala116-->Lys121 using a random targeted mutagenesis procedure developed for this study. The results presented here suggest an important role for this region in the stabilization of the thymine dimer-containing substrate. These mutants also confirm a direct correlation between survival and both DNA binding and pyrimidine dimer-DNA glycosylase activity. No such correlation exists between survival and AP lyase activity. The results are consistent with the recently published X-ray crystal structure.

Alanine↗
PubMed1993

Properties of an xeroderma pigmentosum revertant cell line expressing endonuclease V.

We have developed a set of cell lines to help distinguish the sequelae of specific lesions in DNA after UV irradiation. Irradiation results in two primary lesions: cyclobutane dimers and pyrimidine-pyrimidone (6-4) photoproducts. The contributions of each to mutation are considered utilizing a spectrum of cell lines with increasing abilities to repair these lesions. In particular, we focus on a revertant of the XP12Ro(M1) cell line from a patient with Xeroderma pigmentosum, XP129, which is capable of repairing (6-4) photoproducts but not cyclobutane dimers. We have successfully introduced the denV gene into these cells which confers the ability to repair cyclobutane dimers. By comparing the results of a shuttle vector mutation experiment with the vector pZ189, we can correlate specific mutations to specific lesions.

Base Sequence↗
PubMed1993

Adenosine administration for neonatal SVT.

Adenosine is a purine nucleoside that impairs conduction through the AV node and is thus effective in terminating tachycardias involving the AV node. Gaining acceptance as the drug of choice for neonatal supraventricular tachycardia (SVT), it is given IV as a rapid bolus with an initial dose of 0.05 mg/kg and can be increased in increments of 0.05 mg/kg every one to two minutes until termination of SVT (to a maximum of 0.25 mg/kg). Because of its half-life of 0.6 to 10 seconds, adenosine will not prevent reinitiation of SVT, therefore other medications should be considered if prophylaxis is required. An advantage of the short half-life is the transient nature of adverse effects, which can include flushing, nondistressing alterations in respiratory pattern, irritability, sinus bradycardia, and varying degrees of AV block. Administration to critically ill infants, including those requiring mechanical ventilation, has been reported. The infant's blood pressure, electrocardiogram, respiratory status, and capillary refill should be monitored before, during, and after adenosine administration.

Adenosine↗
PubMed1987

Transient and stable complementation of ultraviolet repair in xeroderma pigmentosum cells by the denV gene of bacteriophage T4.

In this paper we report both transient and stable complementation of pyrimidine dimer repair in xeroderma pigmentosum cells by the denV gene of bacteriophage T4, coding for endonuclease V, a dimer-specific DNA glycosylase. Cotransfection with pRSVdenV in SV40-transformed XP12RO(M1) cells (complementation group A) restored transient expression of an indicator plasmid (pRSVcat) bearing a UV-inactivated chloramphenicol acetyltransferase (cat) gene. In addition, XP12RO(M1) clones stably transformed by pRSVdenV-SVgpt expressed transient chloramphenicol acetyltransferase activity when transfected with UV-inactivated pRSVcat plasmid. These clones also showed partial restoration of colony forming ability and excision repair synthesis after UV irradiation. Immunofluorescence, using an endonuclease V polyclonal antibody, showed the presence of the phage glycosylase in stably transformed xeroderma pigmentosum cells. The cotransfection assay affords a rapid, sensitive procedure to screen for functional cloned DNA repair genes and to test mutant cells for the deficiency of specific steps in DNA repair, such as incision.

Cells, Cultured↗
PubMed1987

In-vivo studies of amphotericin B liposomes derived from proliposomes: effect of formulation on toxicity and tissue disposition of the drug in mice.

The repeat dose toxicity of various liposomal formulations containing amphotericin B has been determined in mice. In general, small liposomes (e.g. 100-150 nm) were found to be more toxic than their large counterparts (e.g. about 2000 nm). However, the repeat dose toxicity of small liposomes could be diminished substantially by the inclusion of sterol (i.e. ergosterol) into the liposomal membranes. Tissue accumulation studies of amphotericin B after repeat dosing may be a useful adjunct to formulation development.

Amphotericin B↗
PubMed1984

BRL 20459, a novel topically active non-steroidal anti-inflammatory drug.

BRL 20459 is a novel compound which displays anti-inflammatory activity when applied topically in the croton oil and cantharadin rat ear inflammation models. The compound does not inhibit uv-induced erythema in the guinea-pig or granuloma formation in the cotton pellet test in the rat. BRL 20459 does not inhibit prostaglandin synthesis nor does it interact with corticosteroid receptors in the thymus. In contrast to hydrocortisone, BRL 20459 did not cause thymus involution or reduce body weight gain in rats. BRL 20459 would seem to have a different mechanism of action to hydrocortisone, but this mechanism is as yet unknown.

Administration, Topical↗
PubMed1983

The effect of anti-inflammatory and anti-rheumatic drugs on cell accumulation onto nitrocellulose discs implanted subcutaneously into mice.

Nitrocellulose discs were implanted subcutaneously into mice and cell accumulation measured 96 hours later. Cell accumulation was inhibited by the anti-inflammatory steroids hydrocortisone, dexamethasone and triamcinolone acetonide, but higher doses of the latter two compounds were required than are normally used in rat models of inflammation. Cell accumulation was not inhibited by the cyclo-oxygenase inhibitors naproxen, indomethacin, tolmetin or aspirin, nor by the dual cyclo-oxygenase and lipoxygenase inhibitors BW 755C and benoxaprofen. Anti-rheumatic drugs such as D-penicillamine, dapsone and colchicine and the metal chelator 1,10 phenanthroline were all inactive on cell accumulation in this model.

Animals↗
PubMed1980

Induction of cell infiltration and acid hydrolase release into the peritoneal cavity of mice.

An injection of thioglycollate into the peritoneal cavity of mice produced a peak of exudate at 4 h, a peak of total leukocytes at 24 h when the predominant cell was the polymorphonuclear neutrophil, and a secondard macrophage phase beginning 2--3 days after thioglycollate. The release of N-acetylglucosaminidase (EC 3.2.1.30) into the peritoneal fluid paralleled the macrophage phase. The amount of enzyme released was related to the dose of thioglycollate. Neither zymosan (400 micrograms) nor endotoxin (30 micrograms) produced a marked inflammatory response when injected into the peritoneal cavity.

Acetylglucosaminidase↗
PubMed1980

The effect of steroidal and non-steroidal antiinflammatory drugs on chronic muscle inflammation.

Zymosan (400 microgram) and thioglycollate medium (0.1 ml of 2.4% w/v) have each been shown to induce a chronic inflammation when injected into the hamstring muscle of the mouse. The inflammation is characterized by an increase in muscle weight and N-acetylglycosaminidase concentrations. The response is not inhibited by oral treatment with hydrocortisone, dexamethasone or naproxen, but is inhibited by the local injection of methylprednisolone. The relevance of this model to polymyositis and fibrositis is discussed.

Acetylglucosaminidase↗
PubMedDate not supplied

Host cell reactivation of CAT-expression vectors as a method to assay for cloned DNA-repair genes.

We demonstrate the feasibility of using passive host-cell reactivation of a shuttle-vector pRSVcat to detect cloned DNA-repair genes. As models, a transient expression vector, pRSVdenV, and a positive-selection vector, pRSVdenV/SVgpt, were constructed containing the T4 coliphage denV gene, coding for an ultraviolet-specific endonuclease, under promotion of the Rous sarcoma virus (RSV) long-terminal repeat. Cotransfection of one or three copies of pRSVdenV per UV-irradiated pRSVcat molecule into xeroderma pigmentosum (XP) cells (XP12Ro[M1]) resulted in a dramatic increase in transient expression of chloramphenicol acetyl transferase (CAT) activity. XP clones stable transformed by pRSVdenV/SVgpt but not the parent cell line rescued CAT activity from this UV-irradiated reporter gene. The ability to express CAT activity from a UV-irradiated pRSVcat correlated with the presence of the structural denV gene as detected by Southern blot analysis. Post-UV irradiation colony-forming ability and DNA nucleotide excision-repair synthesis were partially restored in XP clones which rescued CAT activity. These results demonstrate the feasibility of using the cloned denV gene with its well characterized pyrimidine cyclobutane dimer-specific endonuclease activity to reconstitute UV-induced DNA repair in human cells deficient in DNA repair. Measuring CAT expression from pRSVcat affords a rapid, sensitive procedure to screen for functional cloned DNA-repair genes and to test mutant cells for defects in DNA repair.

Amino Acid Sequence↗