Biomedical subjects

P S Meissner

Publications and source records attributed to P S Meissner.

5 recordsLinked to original sources

PubMed1997

A novel human prostate-specific, androgen-regulated homeobox gene (NKX3.1) that maps to 8p21, a region frequently deleted in prostate cancer.

We have isolated a prostate-specific gene (NKX3.1) in humans that is homologous to the Drosophila NK homeobox gene family. Northern blot analyses indicate that this gene is expressed at high levels in adult prostate and at a much lower level in testis, but is expressed little or not at all in several other tissues. In an androgen-dependent prostate carcinoma line, LNCaP, NKX3.1 mRNA is expressed at a basal level that was increased markedly upon androgen stimulation; the NKX3.1 mRNA was undetectable in several other human tumor cell lines including two androgen-independent prostate carcinoma lines. The NKX3.1 gene maps to chromosome band 8p21, a region frequently reported to undergo a loss of heterozygosity associated with tissue dedifferentiation and loss of androgen responsiveness during the progression of prostate cancer. Based on these data we propose that NKX3.1 is a candidate gene for playing a role in the opposing processes of androgen-driven differentiation of prostatic tissue and loss of that differentiation during the progression of prostate cancer.

Adult↗

PubMed1987

Bacteriophage lambda cloning system for the construction of directional cDNA libraries.

We have developed a bacteriophage lambda cloning vector, lambda ORF8, that can be used for the construction of cDNA libraries. The wild-type lambda genome contains five BamHI, five EcoRI, and seven HindIII restriction sites that have all been removed from the genome of lambda ORF8. Sites for these endonucleases are present within the multiple cloning site of lambda ORF8. We report a method for preparing cDNAs that can be cloned in a single orientation in our phage vector. The method utilizes the synthesis of double-stranded cDNA, including priming of first-strand synthesis by oligo(dT). After completion of second-strand synthesis, a bifunctional oligodeoxynucleotide linker is ligated to the cDNA fragments. This linker, which contains a BamHI restriction site, will create a HindIII restriction site when ligated to the 3' end of cDNA fragments. Subsequent treatment of methylated cDNA with HindIII and BamHI endonucleases allows these fragments to be cloned directionally into lambda ORF8. To demonstrate the utility of this cloning system, we prepared a library from 5 micrograms of mRNA isolated from phytohemagglutinin-stimulated human peripheral blood lymphocytes. The primary library contained 2 X 10(8) plaque-forming phage, at least 80% of which contain inserts. A portion of the library was examined for the presence of gamma-interferon-related clones to verify the method had generated a library that was representative of phytohemagglutinin-stimulated peripheral blood lymphocytes. This simple and efficient cDNA cloning system significantly reduces the amount of RNA and effort required for the preparation of large directionally cloned libraries.

Bacteriophage lambda↗

PubMed1986

Plasmid DNA profiles as epidemiological markers for clinical and environmental isolates of Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum.

Plasmid DNA was isolated, and profiles of a variety of clinical and environmental isolates of Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum (MAIS) were compared to determine whether plasmid DNA content would be useful as an epidemiological marker for these environmental pathogens. Since plasmids are common in clinical isolates and are stable during culture and exposure to NaOH, plasmid DNA analysis appears to be a suitable epidemiological tool. Based on the high frequency of plasmids in only clinical (56%) and aerosol (75%) isolates and low frequencies in soil (5%), dust (7%), sediment (less than 6%), and water (25%) isolates, the data suggest that MAIS-laden aerosols generated over waters of the southeastern United States are a likely source of human infection.

Aerosols↗

PubMed1986

Epidemiology of infection by nontuberculous mycobacteria. VI. Identification and use of epidemiologic markers for studies of Mycobacterium avium, M. intracellulare, and M. scrofulaceum.

A comparison of clinical and environmental (e.g., soil, dust, water, and aerosol) isolates of the Mycobacterium avium-intracellulare and M. scrofulaceum (MAIS) group has been made. The frequency of M. avium-intracellulare clinical isolates able to grow without OADC enrichment, able to grow at 43 degrees C, or express resistance to streptomycin or cadmium was significantly higher than those among environmental isolates. Only the frequency of clinical M. scrofulaceum isolates able to grow at 43 degrees C and without OADC enrichment was significantly higher than that of environmental isolates. Because of the high frequency of clinical M. avium-intracellulare isolates able to grow without OADC, grow at 43 degrees C, and resistant to streptomycin, these 3 characteristics are suggested for use as epidemiologic markers for MAIS. There were no significant differences between clinical M. avium-intracellulare isolates from 3 widely separated geographic regions. Among M. avium-intracellulare environmental isolates, only those collected in droplets above bodies of water (i.e., aerosols) shared those characteristics unique to clinical MAIS. That observation suggests that these aerosols are a likely source of human MAIS infection. The ability of isolates to grow at 43 degrees C and without OADC enrichment was highly correlated. Gentamicin-, streptomycin-, and D-cycloserine-resistances were also frequently found together. Isolates carrying plasmids and either able to grow at 43 degrees C, without OADC enrichment, or mercury-resistant were found more frequently than expected as well. This suggests their genetic determinants are plasmid-encoded.

Aerosols↗

PubMed1984

Plasmid-encoded mercuric reductase in Mycobacterium scrofulaceum.

A Chesapeake Bay water isolate of Mycobacterium scrofulaceum containing a 115-megadalton plasmid (pVT1) grew in the presence of 100 microM HgCl2 and converted soluble 203Hg2+ to volatile mercury at a rate of 50 pmol/10(8) cells per min. Cell extracts contained a soluble mercuric reductase whose activity was not dependent on exogenously supplied thiol compounds. The enzyme displayed nearly identical activity when either NADH or NADPH served as the electron donor. A spontaneously cured derivative lacking pVT1 failed to grow in the presence of 100 microM HgCl2 and possessed no detectable mercuric reductase activity.

DNA, Bacterial↗