Biomedical subjects

D W Martin

Publications and source records attributed to D W Martin.

At least 37 records · Page 2Linked to original sources

PubMed1994

Analysis of promoters controlled by the putative sigma factor AlgU regulating conversion to mucoidy in Pseudomonas aeruginosa: relationship to sigma E and stress response.

Alginate overproducition by mucoid Pseudomonas aeruginosa is a critical pathogenic determinant expressed by this organism during chronic infections in cystic fibrosis. Conversion to mucoidy and a subsequent loss of mucoid character can occur via different mutations in the algU mucA mucB gene cluster. The algU gene encodes a 22.2-kDa putative alternative sigma factor required for expression of the critical alginate biosynthetic gene algD. In this work, algU transcription was studied by S1 nuclease protection analysis. Transcription from the promoter proximal to the algU coding region was found to be dependent on AlgU. The -35 and -10 sequences of this newly mapped promoter showed strong similarity ot the promoters of two other critical alg genes: algD and algR. The proximal promoter of algR was also shown to depend on algU. Interestingly, the putative -35 and -10 regions of all three promoters displayed striking similarity to the consensus sequence of the sigma E-dependent promoters in Escherichia coli and Salmonella typhimurium. This 24-kDa sigma factor, controlling genes participating in resistance to high temperatures and oxidative stress, has been previously biochemically characterized, but the gene for sigma E remained unidentified. To examine whether AlgU is related to sigma E, the effect of algU inactivation on the sensitivity of P. aeruginosa to killing by heat and reactive oxygen intermediates was tested. Two isogenic pairs of algU+ and algU mutant strains were compared. The algU mutants, irrespective of the mucoid status of the parental strains, displayed increased sensitivity to killing by paraquat, known to generate intracellular superoxide radicals, and heat. Further lgobal homology searches revealed the presence of a previously unrecognized E. coli gene with the predicted gene product showing a striking 66% identity to AlgU. The corresponding gene from S. typhimurium was cloned and sequenced, and it is displayed one amino acid substitution relative to its E. coli equivalent. AlgU and its close homologs in E. coli and S. typhimurium may be functionally related.

Adaptation, Physiological↗

PubMed1994

Activation of the human immunodeficiency virus type 1 long terminal repeat by transforming mutants of human p53.

We have studied the effects of human wild-type and mutant p53s on the long terminal repeat (LTR) promoter of human immunodeficiency virus type 1 (HIV). HeLa cells were cotransfected with a wild-type or mutant p53 expression plasmid and a plasmid containing a chloramphenicol acetyltransferase reporter gene under HIV LTR promoter control. As expected, expression of wild-type p53 inhibited promoter function. Expression of a p53 mutated at any one of the four amino acid positions 175, 248, 273, and 281 correlated with a significant increase of the HIV promoter activity. The HIV LTR was also significantly activated in Saos-2 cells that do not express endogenous p53. This finding suggests a gain-of-transactivation function by mutation of the p53 gene. Cotransfection of wild-type and mutant p53-281G expression plasmids indicated that either the wild type or the mutant was dominant in inhibiting or enhancing promoter activity, respectively, when transfected in excess of the other. Transfection experiments showed transactivation even when the Sp1, NF-kappa B, and TATA sites in the LTR were individually mutated. Synthetic minimal promoter constructs containing two Sp1 sites or two NF-kappa B sites or an ATF site are also significantly activated by the mutant p53-281G. Thus, the mutant protein may activate transcription through interaction with either a general transcription factor or a common factor that bridges the basal transcription machinery and the transcription factors Sp1, NF-kappa B, and ATF.

Activating Transcription Factors↗

PubMed1994

Cloning and expression of an equine herpesvirus 1 origin-binding protein.

Equine herpesvirus 1 (EHV-1) is an important pathogen of horses and is closely related to several important human pathogens, herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) and varicella-zoster virus. The EHV-1 genome contains open reading frames similar in sequence to the HSV-1 replication genes. PCR was used to clone EHV-1 gene 53, which is similar in sequence to the HSV-1 UL9 gene. The gene 53 product has regions of striking similarity to the HSV-1 UL9 and VZV gene 51 products. In vitro transcription and translation of this gene generated a protein of 87 kDa as measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Further characterization of this protein was accomplished through the use of gel shift analysis. The in vitro-synthesized protein bound sequence specifically to EHV-1 OriS as well as HSV-1 OriS. A site was used in gel shift analysis to show that the EHV-1 origin-binding protein bound to the same consensus site as the HSV-1 origin-binding protein, 5'-CGTTCGCACTT-3'. Using a nuclear extract of EHV-1-infected RK13 cells, we have identified an activity that interacts similarly with this consensus site. In gel shift assays, the retarded band arising from the nuclear extract migrated similarly to the retarded band arising from in vitro-translated EHV-1 gene 53. An N-terminal deletion of EHV-1 gene 53 was also created, expressed in vitro, and used in gel shift assays to localize the DNA-binding domain. Results of these experiments indicated that amino acids 1 to 499 were dispensable for binding and that the C-terminal fragment (amino acids 500 to 888) recognized the same consensus site as did the wild-type protein. Thus, the product of EHV-1 gene 53 is an origin-binding protein with a high degree of similarity to the HSV-1 and varicella-zoster virus origin-binding proteins and possibly serves as the initiator of DNA replication in EHV-1.

Animals↗

PubMed1994

Sterol 27-hydroxylase: high levels of activity in vascular endothelium.

Sterol 27-hydroxylase activity in bovine aortic endothelial (BAE) cells in culture has been compared with that in HepG2 cells and in Chinese hamster ovary (CHO) cells using identical culture conditions. The total enzyme activity of BAE cells (3.0 nmol/72 h per mg cell protein) was comparable with that of HepG2 cells (4.0 nmol/72 h per mg protein) and both values were significantly greater than that in CHO cells (0.002 nmol/72 h per mg protein). The enzyme was identified in the mitochondria extracted from BAE cells by Western blotting using an antibody of proven specificity, and its metabolites 27-hydroxycholesterol and 3 beta-hydroxy-5-cholestenoic acid were identified by mass spectrum analysis. The presence of the enzyme in endothelium provides a mechanism for preventing accumulation of intracellular cholesterol by initiating a pathway of bile acid synthesis different from that initiated by 7 alpha-hydroxylation of cholesterol in the liver.

Animals↗

PubMed1994

Overlapping domains on the p53 protein regulate its transcriptional activation and repression functions.

Wild-type p53 has been shown to inhibit transcription from several viral and cellular promoters without known p53-binding sites, while transactivating promoters with p53-binding sites. Using a series of N- and C-terminal p53 deletion mutants and wild-type p53, we have defined the domains on p53 responsible for its transcriptional functions. To test transcriptional activation by p53 we have used a promoter-chloramphenicol acetyltransferase (CAT) construct containing synthetic p53-binding sites. To check transcriptional inhibition by p53 we have used a human cytomegalovirus immediate-early promoter construct, CMV-CAT. Using transient transfection-transcription assays in Saos-2 cells, we determined that the p53 transcriptional activation and repression domains overlap at the N-terminus. This suggests the possibility that the same transcriptional machinery is involved in both functions. A C-terminal deletion up to amino acid 327 (del 393-327) eliminated repression of CMV-CAT, while preserving the transactivation function to a large extent. Using gluteraldehyde cross-linking experiments, we observed that the mutant del 393-327, which is transactivation-competent, but repression-defective, could not oligomerize. Thus, oligomerization of p53 is not required for transactivation, but may be essential for repression. Interestingly, transactivation by the oligomerization-defective mutant could be inhibited by cotransfection with a plasmid expressing the transforming mutant p53-175H.

Gene Deletion↗

PubMed1993

Mechanism of conversion to mucoidy in Pseudomonas aeruginosa infecting cystic fibrosis patients.

Chronic respiratory infections with mucoid Pseudomonas aeruginosa are the leading cause of high mortality and morbidity in cystic fibrosis (CF). The initially colonizing strains are nonmucoid, but in the CF lung they invariably convert into the mucoid, exopolysaccharide alginate-overproducing form causing further deterioration and poor prognosis. Here we report the molecular basis of conversion to mucoidy. The algU gene is required for expression of the key alginate biosynthetic gene algD and encodes a protein homologous to sigma H, an alternative sigma factor regulating sporulation and other post-exponential-phase processes in Bacillus. The algU gene and the negative regulators mucA and mucB constitute the gene cluster controlling conversion to mucoidy. We demonstrate a critical role of mucA in this process based on (i) the presence of frameshift mutations disrupting the mucA coding region in mucoid cells that were absent in nonmucoid parental strains, (ii) genetic complementation of mucA mutations with the mucA+ gene, (iii) allelic replacements with specific mutant mucA genes causing conversion to mucoidy in previously nonmucoid cells, and (iv) detection of identical and additional mucA mutations in clinical mucoid strains isolated from the lungs of CF patients. These results suggest that the switch from the nonmucoid to mucoid state can be caused by inactivation of mucA, resulting in constitutive expression of alginate biosynthetic genes dependent on algU for transcription and that such mutants may be selected in vivo during chronic infections in CF.

Alginates↗

PubMed1993

p53 and SV40 T antigen bind to the same region overlapping the conserved domain of the TATA-binding protein.

In this report we demonstrate that the cloned human TATA-binding protein (TBP) interacts with T antigen. TBP co-immunoprecipitates with T antigen when incubated with the T antigen-specific monoclonal antibody PAb419, and Protein-A agarose. Gel retention analysis with a radiolabeled TATA box-containing probe showed that the complex of TBP and T antigen can bind to the TATA box. Recently, p53 has also been shown to interact with TBP. Using TBP deletion mutants and co-immunoprecipitation experiments with p53 or T antigen, we show that both p53 and T antigen bind to the same region, amino acids 203-275, within the conserved C-terminal domain of TBP. Binding of p53 and T antigen to the same domain on TBP may lead to competition between the two proteins for transcriptional function.

Amino Acid Sequence↗

PubMed1993

p53 binds to the TATA-binding protein-TATA complex.

Earlier reports show that p53, both wild type and mutants, may affect transcription. Wild-type p53 activates promoters with p53-binding sites while inhibiting promoters without binding sites. Mutant p53, on the other hand, has been shown to activate transcription from specific promoters. These observations suggest that both wild-type and mutant p53 may interact with a general transcription factor(s). In this report, we have shown that the cloned TATA-binding protein (TBP) from human and yeast interacts with human p53. TBP co-immunoprecipitates with wild-type or mutant human p53 when incubated with the p53-specific monoclonal antibody and Protein A-agarose. Wild-type murine p53 has also been found to interact with human TBP. Protein blot assays have demonstrated that the interaction between p53 and human TBP is direct. By gel retention analysis, we have shown that the complex of TBP and p53 (both wild type and mutant) can bind to the TATA box. The similar qualitative binding capability of wild-type and mutant p53 with human TBP and the similarity of the two complexes in binding to the TATA box suggest that the functional discrimination between wild-type and mutant p53 may not lie in their ability to bind TBP. The nature of the p53.TBP or p53.TBP.TATA complex may determine the success of transcription.

Animals↗

PubMed1993

Conversion to mucoidy in Pseudomonas aeruginosa.

Chronic respiratory complications in cystic fibrosis, compounded by recurring infections with mucoid Pseudomonas aeruginosa and the associated inflammation, are the primary cause of high mortality in this inheritable disease. Since the conversion of P. aeruginosa into the exopolysaccharide alginate overproducing strains plays a critical role in the establishment of chronic infection, studies are directed towards understanding the processes underlying this phenomenon. The genes (algU, mucA, and mucB) and genetic alterations responsible for conversion to mucoidy have been recently characterized. The mutations leading to the emergence of mucoid strains are superimposed on a regulatory system with elements that resemble those controlling other aspects of bacterial developmental physiology.

Alginates↗

PubMed1993

The role of ATP in swelling-stimulated K-Cl cotransport in human red cell ghosts. Phosphorylation-dephosphorylation events are not in the signal transduction pathway.

Volume-sensitive K-Cl cotransport occurs in red blood cells of many species. In intact cells, activation of K-Cl cotransport by swelling requires dephosphorylation of some cell protein, but maximal activity requires the presence of intracellular ATP. We have examined the relation between K-Cl cotransport activity and ATP in ghosts prepared from human red blood cells. K-Cl cotransport activity in swollen ghosts increased by ATP, and the increase requires Mg so that it almost certainly results from the phosphorylation of some membrane component. However, even in ATP-free ghosts residual volume-sensitive K-Cl cotransport can be demonstrated. This residual cotransport in ATP-free ghosts is greater in the presence of vanadate, a tyrosyl phosphatase inhibitor, and in ghosts that contain ATP cotransport is reduced by genistein, a tyrosyl kinase inhibitor. Okadaic acid, an inhibitor of serine and threonine phosphatases, inhibits K-Cl cotransport in ghosts as it does in intact cells. Experiments in which ghosts were preexposed to okadaic acid showed that the protein dephosphorylation that permits K-Cl cotransport can proceed to completion before the ghosts are swollen and K transport measured and therefore dephosphorylation is not a response to ghost swelling. In experiments with ATP-free ghosts we found that phosphorylation is not necessary to increase the cotransport rate when shrunken ghosts are swollen, nor is rephosphorylation necessary to decrease the cotransport rate when swollen ghosts are shrunken. Cotransport is greater in swollen than in shrunken ghosts even when the swollen and shrunken ghosts have the same concentration of cytoplasmic solutes. We conclude that, although phosphorylation and dephosphorylation modify the activity of the cotransporter in swollen and in shrunken ghosts, neither of these processes nor any other known messenger is involved in signal transduction between the cell volume sensor and the cotransporter as originally proposed by Jennings and Al-Rohil (Jennings, M. L., and N. Al-Rohil. 1990. Journal of General Physiology. 95: 1021-1040).

Adenosine Triphosphate↗

PubMed1993

Differentiation of Pseudomonas aeruginosa into the alginate-producing form: inactivation of mucB causes conversion to mucoidy.

Mucoidy in Pseudomonas aeruginosa is a critical virulence factor associated with chronic respiratory infections in cystic fibrosis. A cluster of three tightly linked genes, algU, mucA and mucB located at 67.5 min, controls development of mucoid phenotype. This locus is allelic with a group of mutations (muc) associated with conversion into constitutively mucoid forms. One of the genes previously characterized in this region, algU, is absolutely required for the transcriptional activation of algD, a critical event in the establishment of mucoidy. AlgU is homologous to the alternative sigma factor sigma H (Spo0H) controlling sporulation and competence in Bacillus. Two genes downstream of algU, mucA and mucB were further characterized in this study. Previous complementation studies have demonstrated that mucA is required for suppression of mucoidy in the muc-2 strain PAO568. In this work, complementation analysis indicated that, in addition, mucB was required for suppression of mucoidy in the muc-25 strain PAO581, and for enhanced complementation of the muc-2 mutation in PAO568. The complete nucleotide sequence of mucA and mucB was determined. Insertional inactivation of mucB on the chromosome of the standard genetic strain PAO resulted in mucoid phenotype, and in a strong transcriptional activation of algD. Thus, a loss of mucB function is sufficient to cause conversion of P. aeruginosa into the mucoid phenotype. Since the algU-mucA-mucB region is a general site where muc mutations have been mapped, it is likely that mucB participates in the emergence of mucoid forms. Both mucA and mucB play a regulatory role in concert with the sigma-like factor AlgU; all three genes, along with signal transduction and histone-like elements, control differentiation of P. aeruginosa into the mucoid phenotype.

Alginates↗

PubMed1993

Characterization of a locus determining the mucoid status of Pseudomonas aeruginosa: AlgU shows sequence similarities with a Bacillus sigma factor.

Overproduction of the exopolysaccharide alginate by Pseudomonas aeruginosa results in mucoid colony morphology and is an important virulence determinant expressed by this organism in cystic fibrosis. Mucoidy is transcriptionally regulated by signal transduction systems and histone-like elements. One point of convergence of regulatory elements controlling mucoidy is the algD promoter. A newly described genetic locus required for algD transcription was characterized in this study. This DNA region, cloned from a nonmucoid PAO strain, was initially isolated on the basis of its ability to suppress mucoidy when present on a plasmid. The suppressing activity was observed in several mucoid PAO derivatives, including strain PAO568, in which the mapped muc-2 mutation is responsible for its mucoid phenotype, and in close to 40% of cystic fibrosis strains tested. Protein expression studies detected two polypeptides with apparent molecular masses of 27.5 and 20 kDa encoded by the region required for the suppression activity. The gene encoding the polypeptide with an apparent molecular mass of 27.5 kDa, termed algU, was further characterized. A functional chromosomal copy of algU was found to be necessary for the expression of mucoidy. Insertional inactivation of algU on the chromosome of the mucoid strain PAO568 abrogated alginate production and algD transcription. DNA sequence analysis revealed sequence similarity of the predicted algU gene product with sigma H (Spo0H), a sigma factor involved in the control of sporulation and competence in Bacillus spp. Physical mapping revealed that algU resided on the same SpeI fragment (F) as did the pruAB locus, known to be tightly linked with genetic determinants (muc) which can confer mucoidy in genetic crosses. When the chromosomal algU copy was tagged with a Tcr cassette (algU::Tcr), a tight genetic linkage of algU with pruAB was demonstrated by F116L-mediated generalized transduction. Moreover, algU::Tcr derivatives of PAO568 (originally carrying the muc-2 marker) lost the ability to transfer mucoidy in genetic crosses. These results suggest that algU, a regulator of algD transcription showing sequence similarity to an alternative sigma factor, and the genes immediately downstream of algU may be associated with a locus participating in the differentiation into the mucoid phenotype.

Alginates↗

PubMed1993

The algD promoter: regulation of alginate production by Pseudomonas aeruginosa in cystic fibrosis.

Pseudomonas aeruginosa mutants that overproduce the exopolysaccharide alginate and assume mucoid phenotype are associated with the establishment of chronic respiratory disease in cystic fibrosis. The initially invading strains are nonmucoid and frequently convert into the mucoid form. Mucoidy is regulated at the transcriptional level, mainly at the promoter of the algD gene. Control of the algD promoter represents a cooperative effort of several types of regulatory elements including bacterial signal transduction factors (principally through the response regulator AlgR) and histone like elements (e.g., Hp1 and possibly IHF). Our more recent studies have shown that conversion to mucoidy is a result of mutations in the muc genes within the algU-mucA-mucB cluster. The algU gene encodes a protein that resembles Spo0H, a sigma factor from Bacillus subtilis, which controls development of sporulation and competence. The mucA and mucB genes appear to control the activity of AlgU. Frameshift mutations that inactivate these proteins result in a strong transcriptional activation of algD, and conversion to mucoidy in both laboratory and clinical strains of P. aeruginosa.

Alginates↗

PubMed1992

Mucoid Pseudomonas aeruginosa and cystic fibrosis: the role of mutations in muc loci.

Mucoid alginate-producing mutants of Pseudomonas aeruginosa are major pathogens in debilitating chronic pulmonary infections in patients with cystic fibrosis. The mucoid phenotype results from alginate biosynthesis whose genes are arranged in at least three chromosomal loci. Structural genes are located at the 34-min region and regulatory genes at 9 min. A third cluster at the 70 min region contains muc mutations which affect transcription of a key structural gene, algD, in response to environmental stimuli. Control of mucoidy includes bacterial signal transduction systems, histone-like elements controlling nucleoid structure and, possibly, factors affecting superhelicity. Thus, the control of mucoidy in P. aeruginosa has become one of the focal systems for analysis of how bacterial pathogens adapt to the host environment.

Alginates↗

PubMed1992

Cross-linking of the erythrocyte (Na+,K+)-ATPase. Chemical cross-linkers induce alpha-subunit-band 3 heterodimers and do not induce alpha-subunit homodimers.

Earlier studies (Periyasamy, S. M., Huang, W.-H., and Askari, A. (1983) J. Biol. Chem. 258, 9878-9885) suggested that Cu2+ and o-phenanthroline induced the formation of cross-linked homodimers between alpha-subunits of the erythrocyte (Na+,K+)-ATPase. This was interpreted as indicating that alpha-subunits existed in close proximity in native erythrocyte membranes. The alpha-subunit and band 3 monomers have similar molecular weights (M(r) approximately 100,000) and exist in the membrane in molar ratios of approximately 1:3000 alpha-subunit:band 3. We explored the possibility that alpha-subunit and band 3 could be induced to form heterodimeric structures in the presence of cross-linking reagents. Using methods similar to those employed in the above-cited reference we demonstrated that cross-linked dimers containing phosphorylated alpha-subunits had proteolytic sensitivity that was inconsistent with the formation of alpha-subunit homodimers and fully consistent with heterodimer formation between alpha-subunit and band 3. The data also indicated that alpha-subunit-band 3 heterodimer formation is dependent on the conformational state of the (Na+,K+)-ATPase. Using the appropriate reagents we obtained cross-linked products which were consistent with heterodimer formation between alpha- and beta-subunits of the (Na+,K+)-ATPase. Our data argue against a close association between pairs of (Na+,K+)-ATPase alpha-subunits in the human red cell membrane.

Copper↗

PubMed1992

Modulation of cellular and viral promoters by mutant human p53 proteins found in tumor cells.

Wild-type p53 has recently been shown to repress transcription from several cellular and viral promoters. Since p53 mutations are the most frequently reported genetic defects in human cancers, it becomes important to study the effects of mutations of p53 on promoter functions. We, therefore, have studied the effects of wild-type and mutant human p53 on the human proliferating-cell nuclear antigen (PCNA) promoter and on several viral promoters, including the herpes simplex virus type 1 UL9 promoter, the human cytomegalovirus major immediate-early promoter-enhancer, and the long terminal repeat promoters of Rous sarcoma virus and human T-cell lymphotropic virus type I. HeLa cells were cotransfected with a wild-type or mutant p53 expression vector and a plasmid containing a chloramphenicol acetyltransferase reporter gene under viral (or cellular) promoter control. As expected, expression of the wild-type p53 inhibited promoter function. Expression of a p53 with a mutation at any one of the four amino acid positions 175, 248, 273, or 281, however, correlated with a significant increase of the PCNA promoter activity (2- to 11-fold). The viral promoters were also activated, although to a somewhat lesser extent. We also showed that activation by a mutant p53 requires a minimal promoter containing a lone TATA box. A more significant increase (25-fold) in activation occurs when the promoter contains a binding site for the activating transcription factor or cyclic AMP response element-binding protein. Using Saos-2 cells that do not express p53, we showed that activation by a mutant p53 was a direct enhancement. The mutant forms of p53 used in this study are found in various cancer cells. The activation of PCNA by mutant p53s may indicate a way to increase cell proliferation by the mutant p53s. Thus, our data indicate a possible functional role for the mutants of p53 found in cancer cells in activating several important loci, including PCNA.

Activating Transcription Factors↗

PubMed1992

Inhibition of viral and cellular promoters by human wild-type p53.

Mutation of the p53 tumor suppressor gene is a recurring event in a variety of human cancers. Wild-type p53 may regulate cell proliferation and has recently been shown to repress transcription from several cellular promoters. We studied the effects of wild-type and mutant human p53 on the human proliferating-cell nuclear antigen promoter and on several viral promoters including the simian virus 40 early promoter-enhancer, the herpes simplex virus type 1 thymidine kinase and UL9 promoters, the human cytomegalovirus major immediate-early promoter-enhancer, and the long terminal repeat promoters of Rous sarcoma virus, human immunodeficiency virus type 1, and human T-cell lymphotropic virus type I. HeLa cells were cotransfected with a wild-type or mutant p53 expression vector and plasmids containing a chloramphenicol acetyltransferase reporter gene under viral (or cellular) promoter control. Expression of wild-type p53 correlated with a consistent and significant (6- to 76-fold) reduction of reporter enzyme activity. A mutation at amino acid 143 of p53 releases this inhibition significantly with all the promoters studied. Expression of a p53 mutated at any one of the five amino acid positions 143, 175, 248, 273, and 281 also correlated with a much smaller (one- to sixfold) reduction of reporter enzyme activity from the herpes simplex virus type 1 thymidine kinase promoter. These mutant forms of p53 are found in various cancer cells. Thus, failure of tumor suppression correlates with loss of the promoter inhibitory effect of p53.

Antigens, Neoplasm↗

PubMed1992

Screening for patients with alcohol problems: severity of patients identified by the CAGE.

Primary care physicians are well situated to identify patients with substance abuse problems and motivate them to seek appropriate assistance, but active programs are the exception. A study in a community setting was undertaken to assess the CAGE (the first letters of key words in a series of four questions about drinking: cut down; annoyed; guilty; and eye-opener), instrument in the routine screening for alcohol problems in both new and established patients. The screening process identified subjects for a pilot evaluation of a motivational interview designed to encourage problem-solving behavior. This article focuses on the screening results and the use of the CAGE instrument. During June and July of 1990, 687 patients of two primary care physicians belonging to a large group practice were asked to complete a health questionnaire that included the CAGE. Those who responded affirmatively to at least two of the four CAGE questions were requested to participate in follow-up assessment of problems associated with alcohol and health. The type and severity of alcohol problems experienced by patients who scored positive on the CAGE are described. Prevalence of a positive score on the CAGE was 8.6 percent with males, smokers, and blue collar and unemployed persons being more likely to score positive. The positive predictive value was .68. Primarily, persons with moderate alcohol problems were identified. Results show that the CAGE instrument is a useful screening device for identifying those with mild to moderate substance abuse problems, increasing the opportunity for intervention prior to serious medical complications. The instrument is easily administered, and has demonstrated relatively high levels of sensitivity and specificity. When combined with assessment and motivational interviews, the CAGE shows promise in the secondary prevention of substance abuse and related health problems.

Adult↗