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Biomedical subjects

S M Adams

Publications and source records attributed to S M Adams.

10 recordsLinked to original sources
PubMed1992

Differential expression of the mitochondrial gene cytochrome oxidase II in benign and malignant breast tissue.

Comparative analysis of expression levels of genes in benign and malignant tumours of the breast has been performed. Differential screening of cDNA libraries identified four genes of the mitochondrial genome as being expressed at different levels in the two tissues compared, but further investigations showed that only the gene encoding subunit 2 of cytochrome c oxidase (COII) is expressed at significantly higher levels in carcinomas compared with fibroadenomas. The mitochondrial genes encoding subunits 2 and 4 of NADH dehydrogenase, and subunit 6 of F0F1ATPase, were not found to be differentially expressed in carcinomas and fibroadenomas. All four genes were expressed in the epithelium of human breast carcinomas, as shown by in situ hybridization. The expression level of the COII gene is also correlated with carcinoma grade. No gross alterations to the mitochondrial DNA from these tumours could be detected. The possible implications of these results on the behavioural differences between fibroadenomas and carcinomas are discussed.

Adenofibroma↗
PubMed1992

Responses of fish populations and communities to pulp mill effluents: a holistic assessment.

Fish populations residing in a river receiving bleached kraft mill effluents (BKME) and in an uncontaminated river were investigated to evaluate causal relationships between exposure to BKME and various indicators of fish health. The Index of Biotic Integrity demonstrated that species richness and composition were much lower in the contaminated river with an obvious imbalance in the trophic structure of the fish community. Biomolecular and biochemical responses such as DNA damage and elevated activity of detoxification enzymes indicated that fish in the contaminated river had been exposed to toxicants. The status of various condition indices such as the liver and visceral somatic indices suggested metabolic and nutritional imbalances in sunfish as a result of exposure to pulp mill effluents. Fish populations in the contaminated river also demonstrated an abnormal size distribution and age structure. Female redbreast sunfish from the BKME-impacted river contained a large number of atretic oocytes and had lower serum levels of estradiol than fish from the reference site. These observations plus data from previous developmental toxicity studies suggest that the primary mechanism by which BKME may affect fish populations in this river is through reproductive dysfunction and recruitment failure. Decreased recruitment may have caused a reduction in population size and resulted in decreased competition and increased resource availability. With increased food and habitat availability, more energy may have been available for growth and lipid storage of survivors in the contaminated river.

Animals↗
PubMed1992

Differential expression of translation-associated genes in benign and malignant human breast tumours.

The human gene sequences encoding the translation-associated functions of alpha-subunit of elongation factor 1 (EF-1 alpha) and the ubiquitin carboxyl extension protein (HUBCEP80) have been isolated by differential cDNA screening, and found to have significantly higher levels of expression in fibroadenomas (benign) compared with carcinomas (malignant) of the breast. These data parallel our previous findings that the acidic ribosomal phosphoprotein P2 also has higher expression levels in the benign breast tumours (Sharp et al., 1990). In situ hybridisation has shown these genes to be expressed predominantly in the epithelium of breast tumours.

Adenofibroma↗
PubMed1992

Isolation and characterization of a novel gene with differential expression in benign and malignant human breast tumours.

We report the identification of a novel cDNA representing an mRNA showing significantly higher levels of expression in benign breast lesions than in carcinomas. This cDNA was identified by differential screening of a cDNA library generated from a breast carcinoma, and shows consistently higher expression in fibroadenomas than in carcinomas. The expression in both benign and malignant tissues is highest in epithelial cells as determined by in situ hybridization to tissue sections. The nucleotide sequence of the full-length cDNA has been determined, and the deduced protein is highly basic with no signal or transmembrane sequence, but two potential nuclear localization signals. Neither the DNA nor the protein sequence show any significant homology to sequences in current databases. The cDNA hybridizes to multiple sequences within both human and other mammalian genomes, but to single genomic sequences in Drosophila, Physarum and Schizosaccharomyces pombe. This cDNA therefore represents a highly conserved gene sequence. We have identified only one major transcript in human cells, and it seems likely that there are several pseudogenes within the human genome.

Adenofibroma↗
PubMed1991

Genetic organization of the KpnI restriction--modification system.

The KpnI restriction-modification (KpnI RM) system was previously cloned and expressed in E. coli. The nucleotide sequences of the KpnI endonuclease (R.KpnI) and methylase (M. KpnI) genes have now been determined. The sequence of the amino acid residues predicted from the endonuclease gene DNA sequence and the sequence of the first 12 NH2-terminal amino acids determined from the purified endonuclease protein were identical. The kpnIR gene specifies a protein of 218 amino acids (MW: 25,115), while the kpnIM gene codes for a protein of 417 amino acids (MW: 47,582). The two genes transcribe divergently with a intergeneic region of 167 nucleotides containing the putative promoter regions for both genes. No protein sequence similarity was detected between R.KpnI and M.KpnI. Comparison of the amino acid sequence of M.KpnI with sequences of various methylases revealed a significant homology to N6-adenine methylases, a partial homology to N4-cytosine methylases, and no homology to C5-methylases.

Amino Acid Sequence↗
PubMed1990

A sequence previously identified as metastasis-related encodes an acidic ribosomal phosphoprotein, P2.

We have used a metastasis-related human cDNA isolated from a liver metastasis from a colonic adenocarcinoma to screen a human breast carcinoma cDNA library for homologous sequences. Nucleotide sequence analysis of positive clones revealed that the cDNA represents a ribosomal phosphoprotein. P2. The expression of P2 mRNA was significantly higher (Student's t test, one tail; P less than or equal to 0.01) in seven fibroadenomas than in seven carcinomas, with an average five-fold difference. This enhanced expression level P2 mRNA in benign fibroadenomas compared with malignant carcinomas is contrary to that expected, based on earlier work with normal colonic mucosa, colorectal carcinoma and hepatic metastasis. The identification of gene transcripts which differ in abundance and correlate with the metastatic phenotype may be of considerable importance both as diagnostic aids and in defining the changes associated with tumour progression and metastasis at the molecular level. The possible role that ribosomal proteins may play in the progression of carcinoma of the breast is discussed.

Base Sequence↗
PubMed1977

Detection of benzoylecgonine in human urine.

A thin-layer chromatography (TLC) method is described that can be used to detect benzoylecgonine (BE), a metabolite of cocaine, in human urine. It is a two-part procedure that can be integrated into a rapid screening program for drug abuse. The first part of the method utilizes two TLC solvent systems to identify a variety of drugs, including BE. The second part is specific for the cocaine metabolite and can be used as a confirmation method. The procedure is sensitive to 3-4 microgram/ml of BE in urine.

Chromatography, Thin Layer↗
PubMed1976

Radioimmunuassay compared to thin-layer and gas--liquid chromatography for detecting methadone in human urine.

Radioimmunoassay was compared to thin-layer and gas--liquid chromatographic methods for detection of methadone in the urine of patients undergoing methadone maintenance therapy as treatment of heroin abuse. With urine samples known to contain methadone, 84% were positive by thin-layer chromatography as compared to 99% positives by the other two methods. This difference is attributed to the difference in sensitivity of the three methods. All three methods gave consistently positive results with urine samples from patients receiving 25 mg of methadone per day or more. With smaller daily doses the percentage of positive results obtained with thin-layer chromatography decreased. Analysis of urine samples not containing methadone showed no incidence of cross reaction of other drugs with the methadone radioimmunoassay. The methadone radioimmunoassay appears to be both sensitive and reliable; however, certain other factors limit its use as a primary screening method.

Chromatography, Gas↗