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Biomedical subjects

D R Masys

Publications and source records attributed to D R Masys.

At least 19 recordsLinked to original sources
PubMed2001

Use of keyword hierarchies to interpret gene expression patterns.

MOTIVATION: High-density microarray technology permits the quantitative and simultaneous monitoring of thousands of genes. The interpretation challenge is to extract relevant information from this large amount of data. A growing variety of statistical analysis approaches are available to identify clusters of genes that share common expression characteristics, but provide no information regarding the biological similarities of genes within clusters. The published literature provides a potential source of information to assist in interpretation of clustering results. RESULTS: We describe a data mining method that uses indexing terms ('keywords') from the published literature linked to specific genes to present a view of the conceptual similarity of genes within a cluster or group of interest. The method takes advantage of the hierarchical nature of Medical Subject Headings used to index citations in the MEDLINE database, and the registry numbers applied to enzymes.

Abstracting and Indexing↗
PubMed2001

Temporal gene regulation during HIV-1 infection of human CD4+ T cells.

CD4(+) T-cell depletion is a characteristic of human immunodeficiency virus type 1 (HIV-1) infection. In this study, modulation of mRNA expression of 6800 genes was monitored simultaneously at eight time points in a CD4(+) T-cell line (CEM-GFP) during HIV infection. The responses to infection included: (1) >30% decrease at 72 h after infection in overall host-cell production of monitored mRNA synthesis, with the replacement of host-cell mRNA by viral mRNA, (2) suppression of the expression of selected mitochondrial and DNA repair gene transcripts, (3) increased expression of the proapoptotic gene and its gene p53-induced product Bax, and (4) activation of caspases 2, 3, and 9. The intense HIV-1 transcription resulted in the repression of much cellular RNA expression and was associated with the induction of apoptosis of infected cells but not bystander cells. This choreographed host gene response indicated that the subversion of the cell transcriptional machinery for the purpose of HIV-1 replication is akin to genotoxic stress and represents a major factor leading to HIV-induced apoptosis.

CD4-Positive T-Lymphocytes↗
PubMed1999

PCASSO: a design for secure communication of personal health information via the internet.

The Internet holds both promise and peril for the communications of person-identifiable health information. Because of technical features designed to promote accessibility and interoperability rather than security, Internet addressing conventions and transport protocols are vulnerable to compromise by malicious persons and programs. In addition, most commonly used personal computer (PC) operating systems currently lack the hardware-based system software protection and process isolation that are essential for ensuring the integrity of trusted applications. Security approaches designed for electronic commerce, that trade known security weaknesses for limited financial liability, are not sufficient for personal health data, where the personal damage caused by unintentional disclosure may be far more serious. To overcome these obstacles, we are developing and evaluating an Internet-based communications system called PCASSO (Patient-centered access to secure systems online) that applies state of the art security to health information. PCASSO includes role-based access control, multi-level security, strong device and user authentication, session-specific encryption and audit trails. Unlike Internet-based electronic commerce 'solutions,' PCASSO secures data end-to-end: in the server; in the data repository; across the network; and on the client. PCASSO is designed to give patients as well as providers access to personal health records via the Internet.

Computer Security↗
PubMed1999

Assurance: the power behind PCASSO security.

The need for security protection in Internet-based healthcare applications is generally acknowledged. Most healthcare applications that use the Internet have at least implemented some kind of encryption. Most applications also enforce user authentication and access control policies, and many audit user actions. However, most fall short on providing strong assurances that the security mechanisms are behaving as expected and that they cannot be subverted. While no system can claim to be totally "bulletproof," PCASSO provides assurance of correct operation through formal, disciplined design and development methodologies, as well as through functional and penetration testing. Through its security mechanisms, backed by strong system assurances, PCASSO is demonstrating "safe" use of public data networks for health care.

Computer Security↗
PubMed1998

PCASSO: a secure architecture for access to clinical data via the Internet.

Patient Centered Access to Secure Systems Online (PCASSO) is a National Information Infrastructure research project funded by the US National Library of Medicine (NLM). PCASSO is specifically designed to address the problem of enabling secure access to health information over the Internet, not just for healthcare providers and medical researchers, but also for patients to view their own medical records. The project is using familiar Web technologies to support the search and retrieval of information, including patient demographics, medications, lab tests, and transcription reports. State-of-the-art security technologies protect patient privacy and the integrity of patient information. This paper describes the security architecture of the PCASSO system.

Computer Security↗
PubMed1998

Advances in information technology. Implications for medical education.

Few kinds of technology have had as broad an impact on the recent affairs of humanity as have information technologies. The appearance and rapid spread in the past several years of innovations such as the Internet's World Wide Web and the emergence of computer networks connecting tens to hundreds of millions of people worldwide have occurred with startling rapidity. These global events portend substantial changes in the delivery of health care, the conduct of biomedical research, and the undergraduate, graduate, and continuing education of health professionals. This report will attempt to succinctly review the following: (1) the characteristics of modern information technologies and recent trends that are most relevant to medical education and to the world in which future practitioners, researchers, and educators will live and work; (2) the implications of these technologies for the development of educational goals (in other words, the specific information technology skills that future health professionals will need); (3) the issues associated with the use of these technologies in the process of education; and (4) implications for near-term action by University of California medical schools and academic medical centers.

California↗
PubMed1998

Protecting clinical data on Web client computers: the PCASSO approach.

The ubiquity and ease of use of the Web have made it an increasingly popular medium for communication of health-related information. Web interfaces to commercially available clinical information systems are now available or under development by most major vendors. To the extent that such interfaces involve the use of unprotected operating systems, they are vulnerable to security limitations of Web client software environments. The Patient Centered Access to Secure Systems Online (PCASSO) project extends the protections for person-identifiable health data on Web client computers. PCASSO uses several approaches, including physical protection of authentication information, execution containment, graphical displays, and monitoring the client system for intrusions and co-existing programs that may compromise security.

Computer Security↗
PubMed1997

Patient-Centered Access to Secure Systems Online (PCASSO): a secure approach to clinical data access via the World Wide Web.

The Internet's World-Wide Web (WWW) provides an appealing medium for the communication of health related information due to its ease of use and growing popularity. But current technologies for communicating data between WWW clients and servers are systematically vulnerable to certain types of security threats. Prominent among these threats are "Trojan horse" programs running on client workstations, which perform some useful and known function for a user, while breaching security via background functions that are not apparent to the user. The Patient-Centered Access to Secure Systems Online (PCASSO) project of SAIC and UCSD is a research, development and evaluation project to exploit state-of-the-art security and WWW technology for health care. PCASSO is designed to provide secure access to clinical data for healthcare providers and their patients using the Internet. PCASSO will be evaluated for both safety and effectiveness, and may provide a model for secure communications via public data networks.

Computer Communication Networks↗
PubMed1996

The informatics of health care reform.

Health care in the United States has entered a period of economic upheaval. Episodic, fee-for-service care financed by indemnity insurance is being replaced by managed care financed by fixed-price, capitated health plans. The resulting focus on reducing costs, especially in areas where there is competition fueled by oversupply of health services providers and facilities, poses new threats to the livelihood of medical libraries and medical librarians but also offers new opportunities. Internet services, consumer health education, and health services research will grow in importance, and organizational mergers will provide librarians with opportunities to assume new roles within their organizations.

Advertising↗
PubMed1992

An evaluation of the source selection elements of the prototype UMLS Information Sources Map.

The Information Sources Map (ISM) is a component of the National Library of Medicine's Unified Medical Language System (UMLS) project. The ISM is intended to provide both human-readable and machine-interpretable information about the content, scope, and access conditions for various information sources such as databases, expert systems, and the organizations which make these information sources available. Automated source selection is supported by three types of indexing in the ISM: Medical Subject Heading (MeSH) terms and subheadings; Semantic Types from the UMLS Semantic Network; and Semantic Type Relations, which depict pairs of semantic types joined by a relationship chosen from the Semantic Network. This paper reports a study of the recall and precision of the source selection elements in the prototype version of the ISM.

Abstracting and Indexing↗
PubMed1987

Technical information programs of the National Cancer Institute.

Since its founding in 1937, the National Cancer Institute (NCI) has supported a substantial program of information dissemination. Two peer-reviewed journals, begun in 1940 and 1959, are supplemented by a congressionally mandated International Cancer Research Data Bank (ICRDB), established in 1972. The NCI has made available online databases of published cancer literature and cancer research in progress for the past decade, using the National Library of Medicine (NLM) MEDLARS system. Recently, a clinical-practice-oriented cancer-information system called Physician Data Query (PDQ) has been developed for access at the NLM, as well as through commercial database vendors. The impact of the NCI information programs is currently under prospective evaluation.

Humans↗