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Biomedical subjects

M Sullivan

Publications and source records attributed to M Sullivan.

At least 397 records · Page 22Linked to original sources
PubMed1982

Modification of the Vickers SP120 continuous flow analyser to accommodate the Scandinavian recommended conditions of enzyme analysis for aspartate aminotransferase, lactate dehydrogenase and alkaline phosphatase.

It is important that recommendations of expert bodies for the estimation of enzymes are not undermined by laboratories at District General Hospital level adopting manufacturers' procedures. Three enzyme assay methods are presented which enable adaptation of SCE kinetic methods to the end point type of determination performed on the Vickers SP120 continuous flow analyser. Despite the differences in analytical principle, good precision and correlation was obtained.

Alkaline Phosphatase↗
PubMed1982

Monoclonal antibody to Mullerian inhibiting substance.

Mullerian Inhibiting Substance (MIS) is a testicular product that causes the regression of the Mullerian duct in the developing male embryo. Antibody specific for MIS would facilitate the purification and study of this "hormone," but because of its impure status, traditional polyclonal antisera specific for MIS would be untenable. The requisite specificity, however, might be obtained by the technique of somatic fusion, regardless of the purity of the immunizing antigen. This paper describes the production of 2 monoclonal antibodies specific for MIS by the technique of somatic cell fusion. Spleen cells from mice immunized with an impure preparation of MIS were fused with myeloma cell line NS1. Culture media from the resulting hybridoma cell lines were screened for anti-MIS antibody by a sensitive RIA. Specificity for MIS was demonstrated by the adsorption of biologically active MIS on an affinity column prepared from monoclonal anti-MIS antibody. MIS activity as assessed by an organ culture assay was subsequently recovered from the affinity column in the fraction eluted with MH4SCN. Using the RIA, monoclonal anti-MIS antibody was also shown to compete favorably with a variety of potentially cross-reactive proteins.

Animals↗
PubMed1981

Structures of two spliced herpes simplex virus type 1 immediate-early mRNA's which map at the junctions of the unique and reiterated regions of the virus DNA S component.

We have examined the structures of two herpes simplex virus type 1 immediate-early (IE) RNAs (IE mRNA-4 and IE mRNA-5) which map at the junctions of the unique (Us) and reiterated regions (TRs/IRs) of the virus DNA short component. Hybrids between IE cytoplasmic RNA and herpes simplex virus type 1 DNA restriction fragments were digested with single-strand-specific nucleases S1 and exonuclease VII, and the products were analyzed by agarose gel electrophoresis. Data obtained with the nuclease digestion technique were confirmed by electron microscopy of R-loop structures formed with polyadenylated IE RNA and virus DNA fragments. It was found that both IE mRNA-4 and IE mRNA-5 contained a 260-base 5'-terminal cotranscript which mapped at equivalent loci within TRs/IRs. These 5'-terminal sequences were shown to be spliced to 3'-terminal cotranscripts of 1,450 bases (for IE mRNA-4) and 1,540 bases (for IE mRNA-5). The 3'-terminal cotranscripts contained sequences encoded by both TRs/IRs and opposite ends of Us, indicating that the introns contained by the IE mRNA-4 and IE mRNA-5 genes, found to be approximately 150 base pairs in size, mapped entirely within the reiterated sequences. The data suggest that these genes may contain common and unique components, and the implications of this model are discussed.

Base Sequence↗
PubMed1980

Isolation and characterization of genomic DNA coding for alpha 2 type I collagen.

We have isolated and characterized a segment of the chick alpha 2 collagen gene by screening a library of chick genomic fragments using as hybridization probe an alpha 2 collagen cDNA clone. Several clones were isolated and one of them, lambda gCOL 204, was used for further studies. The DNA of lambda gCOL 204 hybridizes to a unique species of mRNA the size of alpha 2 collagen mRNA. This mRNA can be translated into a unique polypeptide which comigrates in SDS-gel electrophoresis with pro-alpha 2 collagen. Electron microscopic analysis by R-loop technique indicates that lambda gCOL 204 contains 7Kb of the alpha 2 collagen gene. This 7 Kb piece constitutes the 3' end of the gene. The same clone also contains 9 Kb of DNA that is immediately adjacent to the 3' end of the alpha 2 collagen gene. The cloned segment of the alpha 2 collagen gene is interrupted by 8 intervening sequences of various lengths. The coding sequences for collagen in this clone add up to approximately 1,800 bp, which correspond to about 1/3 of alpha 2 collagen mRNA. DNA sequence analysis of a small coding segment of lambda g COL 204 reveals a characteristic collagen type sequence which encodes for an amino acid sequence identical to a sequence found in calf alpha 2 collagen. The sequence of this region of the protein has not yet been determined for the chick alpha 2 collagen.

Animals↗
PubMed1980

Isolation and characterization of overlapping genomic clones covering the chicken alpha 2 (type I) collagen gene.

A series of overlapping recombinant clones, which cover the alpha 2 (type I) collagen gene, have been isolated by stepwise screening of two libraries of chicken genomic DNA fragments. The first genomic clone was isolated by using a cloned cDNA containing alpha 2 collagen DNA sequences as hybridization probe. The other clones were obtained by a sequence of screenings using defined fragments of the successive genomic clones as hybridization probes. Several types of experiments indicated that the DNA of these clones are truly overlapping and span 55 kilobase pairs of contiguous DNA sequences in the chicken genome. Sequence analysis of small DNA segments of some of these clones confirm that they contain coding sequences which specify alpha 2 collagen. Electron microscopic analysis of hybrids between type I alpha 2 collagen mRNA and the overlapping genomic clones indicates that the chicken alpha 2 collagen gene has a length of at least 37 kilobases, about 7.4 times longer than the corresponding translatable cytoplasmic mRNA. The coding information for alpha 2 collagen is distributed in more than 50 coding sequences which are interrupted by intervening sequences of various sizes. The structure of the gene implies that the conversion of precursor RNA to mature mRNA for alpha 2 collagen includes at least 50 splicing events.

Animals↗
PubMed1980

Frequent site-specific deletion of coliphage lambda murine sarcoma virus recombinants and its use in the identification of a retrovirus integration site.

Stocks of hybrid lambda phages carrying the complete integrated provirus of either m1 or HT1 Moloney murine sarcoma virus, as well as flanking host sequences, frequently contain significant numbers of phages carrying a specific deletion. This deletion arises from a recombination event between the terminally repeated sequences in the provirus that deletes the unique Moloney murine sarcoma virus sequences bracketed by the terminally repeated sequences. Physical mapping has shown that the deletion phage retains one complete copy of the terminally repeated sequence and the flanking mink host sequences. One such deletion, lambdaHT1r+, was used to characterize a mink genomic DNA sequence that contains an HT1 Moloney murine sarcoma virus integration site. This integration site sequence from normal mink cells was also cloned into phage lambda. An analysis of the heteroduplexes between the integration site and the lambdaHT1r+ deletion indicated that no major rearrangement of host sequences occurred upon integration of the Moloney murine sarcoma provirus.

Animals↗
PubMed1980

Tetracycline: a clinical study to determine its effectiveness as long-term adjuvant.

A random double blind crossover study of patients on the effects of tetracycline therapy over a 3-month period revealed that there were no significant differences between the placebo group and tetracycline-treated groups in relation to (1) Gingival Index, (2) Debris Index and (3) Papillary Bleeding. A marked improvement in the Gingival Index occurred after 3 months of treatment in each group resulting from curettage and home care. Papillary bleeding was significantly reduced after 3 months of treatment in the tetracycline group and similar trends were observed in the placebo group. The Debris Index in both experimental and placebo groups showed no significant change after treatment for 3 months. The data suggest that tetracycline therapy does not appreciably after either the Gingival Index, Debris Index, or the Papillary Bleeding Index over a 3-month period.

Clinical Trials as Topic↗
PubMed1979

Extracorporeal immunoadsorption: initial experience in human systemic lupus erythematosus.

Extracorporeal immunoadsorption and filtration was used in treatment of a 29-year-old woman with severe lupus nephritis. For the previous 35 days single-stranded DNA (ssDNA) antibody and immune-complex levels had been continuously raised with only partial improvement on prednisone therapy. Levels of immune complexes and ssDNA antibodies were substantially reduced by extracorporeal plasma filtration and adsorption of DNA collodion charcoal. There were no major clinical complications. After perfusion, the reduction of ssDNA binding and immune complexes in serum was sustained, serum C'3 became normal, and serum creatinine and proteinuria improved. 28 days after perfusion, subendothelial glomerular deposits were much reduced compared with those in a pre-perfusion biopsy specimen. Selective immunoadsorption is a promising new approach to persistent lupus nephritis refractory to drug therapy alone.

Adult↗
PubMed1979

Characterization of a new isolate of poliovirus defective interfering particles.

An independent isolate of poliovirus defective interfering particles has been analyzed. These particles, designated DI(A), are apparently analogous to the DI particles described by Baltimore and co-investigators. Electron microscopic heteroduplex analysis reveals that the DI(A) isolate is a mixture of deletion mutants which changes with passage level. The DI(A) population consists of at least five distinct deletion mutants, including one double deletion. Electron microscopic mapping of the deleted regions indicates that most, if not all, of the viral capsid region can be deleted. Despite this heterogeneity, the mutant genomes are quite similar in physical size. We propose a model which suggests that the observed properties of poliovirus DI genomes reflect selective pressures extant during the amplification of the mutant genome. According to this model, only those deleted genomes which retain a minimal size and the capacity to synthesize a functional viral polymerase will replicate successfully in a mixed infection. Furthermore, this model proposes a mechanism for the enrichment of poliovirus DI genomes and an explanation for the low level of complementation observed in mixed infections of picornaviruses.

Chromosome Deletion↗
PubMed1979

Cloning of integrated Moloney sarcoma proviral DNA sequences in bacteriophage lambda.

We have identified integrated proviral DNA sequences of m1 and HT-1 isolates of Moloney sarcoma virus (MuSV) in EcoRI digests of transformed mink cell genomic DNA and have cloned these fragments in bacteriophage lambda. Both the lambda-HT1 phage recombinant, containing a 12.3-kilobase MuSV pair (kb) fragment, and the lambda-m1 phage recombinant, containing a 7.0-kb fragment, possess full copies of the sarcoma viruses along with 5' and 3' host flanking sequences. The MuSV proviral DNA sequences, 6.7 kb for HT-1 and 5.2 kb for m1, are colinear by heteroduplex microscopy with the 1.5-kb difference in size accounted for by two approximately equal to 0.8-kb deleted regions in m1. Both integrated viral genomes are terminally redundant and have integrated at the same site in the provirus but at different sites on the host chromosome. The host sequence flanking integrated HT-1 MuSV have been identified as a single EcoRI restriction fragment of 5.6 kb in normal mink cells.

Animals↗
PubMed1979

Evening urinary oxalate excretion in stone formers.

Urine collections from stone formers and controls were made between 6 p.m. and midnight and analysed for oxalate content. No difference in oxalate output was found between these groups. This makes it unlikely that hyperabsorption of oxalate from the intestine is a common cause of idiopathic calcium oxalate stones. The convenience of 6-h urine collections for detecting hypercalciuria is discussed.

Calcium Oxalate↗