Biomedical subjects

M Johnsen

Publications and source records attributed to M Johnsen.

At least 19 recordsLinked to original sources

PubMed2001

A precise and efficient stereological method for determining murine lung metastasis volumes.

We have developed a computer-assisted stereological method based on unbiased principles for estimating metastasis volumes in mouse lungs. We evaluated this method using the transplantable Lewis lung carcinoma. Twenty-one days after subcutaneous inoculation of 10(6) Lewis lung cells into C57BL/6J mice, the mice had primary tumors with an average volume of 2300 mm(3). After perfusion fixation, the lungs were removed, embedded in OCT compound, snap-frozen, and processed for stereology. The metastasis volumes were estimated by application of the Cavalieri principle after evaluation of single sections from several evenly distributed tissue levels. The metastasis volume in a group of nine mice varied between 0.01 and 14.4 mm(3), with an average of 6.1 mm(3). The coefficient of variation was 0.9. The coefficient of error of the volume estimation was determined in five cases and varied from 0.08 to 0.23. Thus, the variation on the metastasis volumes that is achieved by this method contributes very little, 2.5%, to the total variance within the group of mice. In conclusion, we have developed an efficient and unbiased method to determine the metastasis burden in mouse lungs.

Animals↗

PubMed2001

Urokinase plasminogen activator is localized in stromal cells in ductal breast cancer.

Urokinase plasminogen activator (uPA) regulates a proteolytic cascade that facilitates cancer invasion through degradation of the extracellular matrix, and high levels of uPA in human breast cancer tissue correlate with poor prognosis. We previously found that, in ductal breast cancer, uPA mRNA is highly expressed by myofibroblasts surrounding invasively growing cancer cells. However, the localization of uPA protein has not been settled in the published literature. Because uPA is a secreted molecule, it could conceivably be localized differently from its mRNA. We have studied the localization of uPA immunoreactivity in detail. Twenty-five cases of invasive ductal carcinoma were analyzed with three different uPA antibody preparations, all of which gave an essentially identical stromal staining pattern. Using double immunofluorescence, we identified uPA immunoreactivity in myofibroblasts and macrophages in all cases examined. Additionally, in approximately half of the tumors, we saw uPA staining of endothelial cells. In 3 of the 25 cases, a small subpopulation of the cancer cells was uPA-positive. We conclude that uPA immunoreactivity is almost exclusively associated with stromal cells, which thus play a major role in generation of proteolytic activity in ductal breast cancer.

Antibody Specificity↗

PubMed2001

Service delivery and community: social capital, service systems integration, and outcomes among homeless persons with severe mental illness.

OBJECTIVES: This study evaluated the influence of features of community social environment and service system integration on service use, housing, and clinical outcomes among homeless people with serious mental illness. STUDY SETTING: A one-year observational outcome study was conducted of homeless people with serious mental illness at 18 sites. DATA SOURCES: Measures of community social environment (e.g., social capital) were based on local surveys and voting records. Housing affordability was assessed with housing survey data. Service system integration was assessed through interviews with key informants at each site to document interorganizational transactions. Standardized clinical measures were used to assess clinical and housing outcomes in face-to-face interviews. RESEARCH DESIGN: Structural equation modeling was used to determine the relationship between (1) characteristics of the social environment (social capital, housing affordability); (2) the level of integration of the service system for persons who are homeless in each community; (3) access to and use of services by individual clients; and (4) successful exit from homelessness or clinical improvement. PRINCIPAL FINDINGS: Social capital was associated with greater service systems integration, which was associated in turn with greater access to assistance from a public housing agency and to a greater probability of exiting from homelessness at 12 months. Housing affordability also predicted exit from homelessness. Neither environmental factors nor systems integration predicted outcomes for psychiatric problems, substance abuse, employment, physical health, or income support. CONCLUSION: Community social capital and service system integration are related through a series of direct and indirect pathways with better housing outcomes but not with superior clinical outcomes for homeless people with mental illness. Implications for designing improved service systems are discussed.

Case Management↗

PubMed2000

Successful systems integration strategies: the access program for persons who are homeless and mentally ill.

In 1993, the Access to Community Care and Effective Services and Supports (ACCESS) federal demonstration program was initiated. Using a quasi-experimental design, the 5-year demonstration program sought to assess the impact of integrated systems of care on outcomes for homeless persons with mental illness. The authors report on which integration strategies were chosen and how their implementation is quantified. Data collected primarily through annual site visits revealed that only two strategies were used by all nine systems. The systems integration strategies employed remained relatively stable over the 5 years. Successful implementation appears to be related to the strategies selected.

Delivery of Health Care, Integrated↗

PubMed1999

Case management models for persons who are homeless and mentally ill: the ACCESS demonstration project. Access to Community Care and Effective Services and Supports.

Persons who are homeless and mentally ill present unique challenges to service providers and human service systems. In vivo case management approaches such as assertive community treatment (ACT) have shown promise in engaging this population. This paper explores case management models employed within the ACCESS program, a five year, 18-site demonstration program enriching services for homeless persons with serious mental illness. We describe the implementation of case management with ACCESS programs and determine the extent of variation across sites using a measure of fidelity to ACT. While programs reported using four models, much similarity was found among programs on multiple dimensions.

Case Management↗

PubMed1999

Characterization of rural mental health service systems.

This paper explores two mental health systems in rural North Carolina that provide services to people with severe mental disorders. Recent findings show rural people with mental disorders receive less mental health care than their urban counterparts. This study asks whether rural service systems differ from urban systems in the way that their services are coordinated and structured. A popular conception is that public mental health systems in the United States are uncoordinated with many services provided outside the mental health sector. Rural service providers are seen as even more dependent on nonspecialized mental health providers than their urban counterparts. While many rural service barriers are attributed to the rural environment, little is known about rural service systems and how their organization might contribute to or negate barriers to care. Social network methods were used in this study to compare two rural with four urban systems of care. Findings confirm that mental health systems fit the de facto hypothesis, but that rural systems differ in ways not anticipated by the hypothesis. Rather than being more dependent on nonmental health agencies, rural mental health agencies are more interdependent.

Health Services Needs and Demand↗

PubMed1998

Cancer invasion and tissue remodeling: common themes in proteolytic matrix degradation.

Analysis of extracellular matrix degradation systems has led to the insight that in cancer invasion there is often crucial interplay between cancer cells and several types of surrounding non-neoplastic stromal cells. Likewise, in normal tissue remodeling processes, the synthesis of proteolytic components is often distributed between several cell types, and there are strong similarities between neoplastic and non-neoplastic processes in the same tissue. Thus, tissue remodeling events are excellent models for studies of extracellular proteolysis in cancer. This has become even clearer by recent analyses of genetically modified mice.

Breast Neoplasms↗

PubMed1998

Using the Referral Decision Scale to screen mentally ill jail detainees: validity and implementation issues.

The prevalence of serious mental illnesses in jail populations is significantly greater than in the general population. Identifying individuals who warrant psychiatric evaluations is important and benefits correctional staff as well as detainees. One widely used screening instrument intended for this task is the Referral Decision Scale (RDS). This paper reviews the development and validation of the RDS. Using data from a multisite study which assessed postrelease outcomes for detainees with mental illness, various types of validity are addressed. The results confirm that the RDS has some inherent characteristics that seriously limit its practical application as a screening instrument for use by correctional staff.

Adult↗

PubMed1998

Service system integration, access to services, and housing outcomes in a program for homeless persons with severe mental illness.

OBJECTIVES: This study evaluated the hypothesis that greater integration and coordination between agencies within service systems is associated with greater accessibility of services and improved client housing outcomes. METHODS: As part of the Access to Community Care and Effective Services and Supports program, data were obtained on baseline client characteristics, service use, and 3-month and 12-month outcomes from 1832 clients seen at 18 sites during the first year of program operation. Data on interorganizational relationships were obtained from structured interviews with key informants from relevant organizations in each community (n = 32-82 at each site). RESULTS: Complete follow-up data were obtained from 1340 clients (73%). After control for baseline characteristics, service system integration was associated with superior housing outcomes at 12 months, and this relationship was mediated through greater access to housing agencies. CONCLUSIONS: Service system integration is related to improved access to housing services and better housing outcomes among homeless people with mental illness.

Adult↗

PubMed1997

In search of the missing linkages: continuity of care in U.S. jails.

Persons with symptoms of acute mental illnesses present problems for jail management. Jails have a constitutional duty to provide psychiatric services to all persons in need of such care. However, mental health resources are frequently insufficient to meet the many needs of persons with mental illnesses in jails, and are often inaccessible to those released to the community. This study focuses on the experiences of a cohort of detainees (n = 379) with mental illnesses who have been incarcerated in seven U.S. jails. Data gathered include criminal and demographic characteristics, mental health services received by the detainees in jail, discharge planning activities by jail staff, and community-based outcomes after release. This is primarily a descriptive study depicting typical experiences and processes related to detainees with mental illnesses. The goal is to provide information to support more detailed studies on the effectiveness of mental health-criminal justice linkages.

Adult↗

PubMed1997

Service system performance and integration: a baseline profile of the ACCESS demonstration sites. Access to Community Care and Effective Services and Supports.

OBJECTIVE: Networks of agencies at the 18 demonstration sites in the Access to Community Care and Effective Services and Supports (ACCESS) program for homeless persons with serious mental illness were surveyed to profile baseline levels of systems performance and integration as part of a longitudinal evaluation of systems change and client outcomes. METHODS: Interviews were conducted with a representative from each of 875 agencies in the 18 service networks. Information was obtained about the perceived performance of the service system and the extent of systems integration as measured by client referrals, funds exchanges, and information sharing between agencies. Measures consisted of two multi-item scales assessing the accessibility and coordination of services for the target population in each community and four indexes of interagency relationships. RESULTS: Services at baseline for homeless mentally ill persons at the program sites were rated as relatively inaccessible, and the coordination of services between agencies was rated as even more problematic. Interagency ties were largely based on client referrals and information exchanges, with very few instances of funding transfers in the form of contracts or grants. On average, at baseline agencies that had received an ACCESS grant were better connected to their local service network than were other agencies. CONCLUSIONS: Consistent with the premise of the ACCESS demonstration, services for persons who are homeless and mentally ill in urban America are fragmented and not very accessible. The longitudinal design of the evaluation will allow for an assessment of efforts to improve services and systems integration and of the effects of these improvements on client outcomes.

Adult↗

PubMed1992

A novel complex between the p65 subunit of NF-kappa B and c-Rel binds to a DNA element involved in the phorbol ester induction of the human urokinase gene.

The NF-kappa B subunits, p50 and p65, have extensive sequence homology with the c-rel proto-oncogene and the Drosophila morphogen dorsal. It has recently been shown that in vitro translated c-Rel can bind to DNA and form a complex with p50. However, the conditions for DNA binding of c-Rel in vivo and its DNA sequence specificity have not been established. Here we report the identification a novel heterodimeric complex that binds to a kappa B-like, phorbol ester (TPA) responsive DNA sequence, 5'-GGGAAAGTAC-3', in the 5' flanking region of the human urokinase (uPA) gene. This sequence was shown to bind two protein complexes, LC and UC. LC was indistinguishable from NF-kappa B as it reacted with antibodies recognizing the p50 subunit of NF-kappa B, and was shown by UV crosslinking to contain the p50 and p65 subunits of NF-kappa B. UC, on the other hand, strongly reacted with anti-v-Rel, but not with the anti-p50 antibodies, and was shown by crosslinking to contain 75 kDa and 85 kDa protein-DNA adducts. The 75 kDa and the 85 kDa adducts could be immunoprecipitated only by anti-p65 and anti-c-Rel antibodies, respectively, showing that c-Rel formed a heterodimer with p65. Both protein complexes were present in inactive forms in HeLa cell cytosol, and their nuclear translocation was induced by TPA. DNA binding of UC and LC could, furthermore, be inhibited by I kappa B-alpha.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗

PubMed1992

A regulatory element that mediates co-operation between a PEA3-AP-1 element and an AP-1 site is required for phorbol ester induction of urokinase enhancer activity in HepG2 hepatoma cells.

We have characterized a transcriptional enhancer of the human urokinase-type plasminogen activator (uPA) gene and found a regulatory element required for co-operation between a PEA3--AP-1 element and an AP-1 site in the enhancer. We designated this regulatory element co-operation mediator (COM). Both the PEA3--AP-1 element, the AP-1 site and the COM are required for efficient phorbol ester induction of transcription from the uPA promoter in the HepG2 hepatoma cell line. We show that the COM is also required for co-operation between the PEA3--AP-1 element and a glucocorticoid response element, both in the presence or absence of TPA, indicating that the COM is generally capable of mediating synergism between inducible enhancer elements. The COM contains multiple overlapping binding sites for nuclear proteins, designated uPA enhancer factors 1-4 (UEF-1-4). We have identified putative binding sites for UEF-1, -2 and -3. The UEF-1 and -3 sites in the uPA enhancer are highly conserved between species. We demonstrate the binding of UEF-3 to the NIP element, a previously characterized regulatory element in the human interleukin-3 and stromelysin promoters, suggesting that this factor plays a role in regulation of a variety of genes.

Base Sequence↗

PubMed1991

Essential AP-1 and PEA3 binding elements in the human urokinase enhancer display cell type-specific activity.

We have characterized a transcriptional enhancer of the human urokinase-type plasminogen activator (uPA) gene in three transformed human cell lines: HeLa, HepG2 and HT1080. The enhancer is located approximately 2 kbp upstream of the mRNA cap site and is active in all three cell lines. By footprinting and gel retardation analysis we found that it contained two binding sites for transcription factor AP-1, encoded by the fos and jun proto-oncogene families. The most upstream of these sites was juxtaposed to a binding site for PEA3, a product of the ets/Spi proto-oncogene family. By transient transfection analysis of deletions, point mutations and subcloned fragments, we found these sites to be crucial for enhancer activity. However, the sites displayed differences in activity in the three different cell lines. The downstream AP-1 site was almost exclusively responsible for enhancer activity in HeLa cells, whereas the AP-1/PEA3 site played a major role in HT1080 and HepG2 cells. The implications of our findings for the known regulation of uPA expression by transforming oncogenes, adenovirus E1A protein and glucocorticoids are discussed.

Base Sequence↗

PubMed1990

Transcription factor PEA3 participates in the induction of urokinase plasminogen activator transcription in murine keratinocytes stimulated with epidermal growth factor or phorbol-ester.

Keratinocytes in culture represent cells which exhibit continued and controlled growth in the organism. We have investigated the synthesis of urokinase plasminogen activator mRNA in exponentially growing cultures of primary murine keratinocytes and the keratinocyte cell line BALB/MK. The tumor promotor 12-O-tetradecanoyl phorbol-13-acetate (TPA) and epidermal growth factor (EGF) induced urokinase mRNA synthesis. We made a series of progressive 5' deletions as well as internal deletions in the region upstream of the murine uPA gene. These were joined to the cat reporter gene, and used to map the TPA and EGF responsive regions of the promoter. We found both responsive sequences within a 90 base pair Hae III fragment, located 2.4 kb. upstream of the mRNA cap site. This DNA fragment conferred TPA inducibility on reporter gene expression independent of its distance and orientation to the transcription initiation site. Footprinting and gel retardation studies identified the responsible sequence to be a binding site for PEA3 juxtaposed to an octameric TRE-element. Transfections with point mutants showed that these target sequences were necessary for TPA and EGF induction of transcription.

Animals↗

PubMed1986

A transforming ras gene can provide an essential function ordinarily supplied by an endogenous ras gene.

Microinjection of monoclonal antibody Y13-259, which reacts with all known mammalian and yeast ras-encoded proteins, has previously been shown to prevent NIH 3T3 cells from entering the S phase (L. S. Mulcahy, M. R. Smith, and D. W. Stacey, Nature [London] 313:241-243, 1985). We have now found several transformation-competent mutant v-rasH genes whose protein products in transformed NIH 3T3 cells are not immunoprecipitated by this monoclonal antibody. These mutant proteins are, however, precipitated by a different anti-ras antibody. Each of these mutants lacks Met-72 of v-rasH. In contrast to the result for cells transformed by wild-type v-rasH, Y13-259 microinjection of NIH 3T3 cells transformed by these mutant ras genes did not prevent the cells from entering the S phase. These results imply that a transformation-competent ras gene can supply a normal essential function for NIH 3T3 cells. When the proteins encoded by the mutant ras genes were overproduced in Escherichia coli, several mutant proteins that lacked Met-72 failed to bind Y13-259 in a Western blot. However, a ras protein from a mutant lacking amino antibody, but a ras protein from a mutant lacking amino acids 72 to 84 did not. These results suggest that Y13-259 may bind to a higher ordered structure that has been restored in the mutant lacking amino acids 72 to 82.

Animals↗

PubMed1986

Mutational analysis of a ras catalytic domain.

We used linker insertion-deletion mutagenesis to study the catalytic domain of the Harvey murine sarcoma virus v-rasH transforming protein, which is closely related to the cellular rasH protein. The mutants displayed a wide range of in vitro biological activity, from those that induced focal transformation of NIH 3T3 cells with approximately the same efficiency as the wild-type v-rasH gene to those that failed to induce any detectable morphologic changes. Correlation of transforming activity with the location of the mutations enabled us to identify three nonoverlapping segments within the catalytic domain that were dispensable for transformation and six other segments that were required for transformation. Segments that were necessary for guanosine nucleotide (GDP) binding corresponded to three of the segments that were essential for transformation; two of the three segments share strong sequence homology with other purine nucleotide-binding proteins. Loss of GDP binding was associated with apparent instability of the protein. Lesions in two of the three other required regions significantly reduced GDP binding, while small lesions in the last required region did not impair GDP binding or membrane localization. We speculate that this latter region interacts with the putative cellular target of ras. The results suggest that transforming ras proteins require membrane localization, guanosine nucleotide binding, and an additional undefined function that may represent interaction with their target.

Arginine↗

PubMed1984

JINN, an integrated software package for molecular geneticists.

I describe JINN, a microcomputer-based system designed to maintain and search a strain collection, to enter, modify and analyze sequences, and to use the EMBL Sequence Data Base. The major objective during development of this program has been integration of individual program modules to ensure a consistent and helpful user interface. The system is running under the CP/M operating system and requires little in the way of particular hardware configuration.

Amino Acid Sequence↗