Organization of HIV-1 capsid proteins on a lipid monolayer

In an in vitro system that mimics the assembly of immature human immunodeficiency virus (HIV) particles, ordered arrays of HIV-1 capsid (CA) proteins encoded by the viral gag gene have been obtained by incubation of histidine-tagged capsid proteins (His-HIVCA) beneath lipid monolayers containing the nickel-chelating lipid, 1,2-di-O-hexadecyl-sn-glycero-3-(1'-2"-R-hydroxy-3'-N-(5-amino-1- carboxypentyl)iminodiacetic acid)propyl ether. The membrane-bound His-HIVCA proteins formed small crystalline arrays of primitive (p1) unit cells with dimensions of a = 74.2 A, b = 126.2 A, gamma = 89.3 degrees. The image-analyzed two-dimensional projection of His-HIVCA assemblies shows a cage-like lattice, consisting of hexamer and trimer units, surrounding protein-free cage holes. The hexamer-coordinated cage holes of 26.3-A diameter are spaced at 74. 2-A intervals: these distances, and the hexamer-trimer arrangement, are consistent with previous, lower resolution studies on immature HIV-1 virus particles produced in vivo. Additionally, HIV-1 matrix protein trimer unit structures align to the His-HIVCA trimer units such that residues previously shown to interact with the HIV-1 gp120/gp41 envelope protein complex are oriented toward the hexamer cage holes. Our results form a bridge between results from conventional methods for the analysis of HIV particle structure.

Creation and maintenance of Helix, a Web based database of medical genetics laboratories, to serve the needs of the genetics community

Helix (healthlinks.washington.edu/helix) is a web accessible database that serves as the main U.S. directory of laboratories offering genetic testing. The database was designed to address the previously unmet need for a centralized, continuously updated source of information about clinical and research genetic testing to keep pace with the rapid rate of gene discovery resulting from the Human Genome Project. The Helix project began in 1992 at the University of Washington and Children's Hospital and Regional Medical Center. It has evolved from a single user stand alone relational database to a fully Web enabled database queried and maintained via the web and linked to other web accessible genomic databases. As of February, 1998 it lists more than 500 diseases and 290 laboratories, with over 5,200 registered users making approximately 250 queries/day (90% via the Internet). We describe the iterative design, implementation, population and assessment of the database over a six year period.

Structural analysis of membrane-bound retrovirus capsid proteins

We have developed a system for analysis of histidine-tagged (His-tagged) retrovirus core (Gag) proteins, assembled in vitro on lipid monolayers consisting of egg phosphatidylcholine (PC) plus the novel lipid DHGN. DHGN was shown to chelate nickel by atomic absorption spectrometry, and DHGN-containing monolayers specifically bound gold conjugates of His-tagged proteins. Using PC + DHGN monolayers, we examined membrane-bound arrays of an N-terminal His-tagged Moloney murine leukemia virus (M-MuLV) capsid (CA) protein, His-MoCA, and in vivo studies suggest that in vitro-derived His-MoCA arrays reflect some of the Gag protein interactions which occur in assembling virus particles. The His-MoCA proteins formed extensive two-dimensional (2D) protein crystals, with reflections out to 9.5 A resolution. The image-analyzed 2D projection of His-MoCA arrays revealed a distinct cage-like network. The asymmetry of the individual building blocks of the network led to the formation of two types of hexamer rings, surrounding protein-free cage holes. These results predict that Gag hexamers constitute a retrovirus core substructure, and that cage hole sizes define an exclusion limit for entry of retrovirus envelope proteins, or other plasma membrane proteins, into virus particles. We believe that the 2D crystallization method will permit the detailed analysis of retroviral Gag proteins and other His-tagged proteins.

Meeting clinician information needs by integrating access to the medical record and knowledge resources via the Web

MINDscape is a web based integrated interface to diverse sources of clinical information including both patient specific information (electronic medical record) as well as medical knowledge (the "digital library") to provide "just in time" information at the point of care. It was developed at the University of Washington to meet clinical information needs both as identified locally and by a review of the literature. Beta testing by over 600 clinicians is in progress and medical centers wide access scheduled for Fall 1997. We describe the information needs we sought to meet and the ongoing evaluation approach we are taking to ensure the information needs of a diverse group of clinicians are met. The iterative evolution of the interface from prototype, to alpha to large scale beta testing is reported. Integration of information occurs at three levels: integration of information by patient, integration of information by provider, and integration of patient specific information with medical reference material and decision support tools.

Regional health information systems: applying the IAIMS model

In general, there is agreement that robust integrated information systems are the foundation for building successful regional health care delivery systems. Integrated Advanced Information Management System (IAIMS) institutions that, over the years, have developed strategies for creating cohesive institutional information systems and services are finding that IAIMS strategies work well in the even more complex regional environment. The key elements of IAIMS planning are described and lessons learned are discussed in the context of regional health information systems developed. The challenges of aligning the various information agencies and agendas in support or a regional health information system are complex; however, the potential rewards for health care in quality, efficacy, and cost savings are enormous.

Combination but not single-agent methotrexate chemotherapy for gestational trophoblastic tumors increases the incidence of second tumors

PURPOSE

No increase in second tumor incidence was found in a previous analysis of women treated with chemotherapy for gestational trophoblastic tumors (GTT). More patient years at risk enabled a further analysis of the risk of second tumors to be performed in the 1,377 women treated in this until up to 1990.

PATIENTS AND METHODS

Health questionnaires were returned on 93.3% of patients who successfully completed chemotherapy and were living in the United Kingdom. The remainder were flagged for death or developing further cancers by the Office of Population Census and Surveys and by the Thames Cancer Registry. Incidence density analysis was performed based on 15,279 person-years of observation available. Standardized incidence ratio (SIR) was used to estimate the relative risk (RR) of second tumors associated with the treatment. To calculate the expected number, the actual incidence rates observed by the Thames Cancer Registry during the same calendar period of observation were used.

RESULTS

An overall 50% excess of risk (RR = 1.5; 95% confidence interval [CI], 1.1 to 2.1; P < .011) was observed: there were 37 second tumors, when 24.5 were expected. For specific second tumors, the risk was significantly increased for myeloid leukemia (RR = 16.6; 95% CI, 5.4 to 38.9), colon (RR = 4.6; 95% CI, 1.5 to 10.7), and breast cancer when the survival exceeded 25 years (RR = 5.8; 95% CI, 1.2 to 16.9). The risk was not significantly increased among the 554 women receiving single-agent therapy (RR = 1.3; 95% CI, 0.6 to 2.1). Leukemias only developed in patients receiving etoposide plus other cytotoxic drugs.

CONCLUSION

This study suggests that there is a slight increased risk of second tumors after sequential or combination chemotherapy for GTT. This has become apparent since the introduction of etoposide and longer follow-up.

Managing information in the academic medical center: building an integrated information environment

The strategic importance of integrated information systems and resources for academic medical centers should not be underestimated. Ten years ago, the National Library of Medicine in collaboration with the Association of Academic Medical Centers initiated the Integrated Advanced Information Management System (IAIMS) program to assist academic medical centers in defining a process for addressing deficiencies in their information environments. The authors give a brief history of the IAIMS program, and they describe both the characteristics of an integrated information environment and the technical and organizational structures necessary to create such an environment. Strategies some institutions have used to implement integrated information systems are also outlined. Finally, the authors discuss the role of librarians in integrated information system design.

Presentation and management of choriocarcinoma after nonmolar pregnancy

OBJECTIVE

To ascertain the mode of presentation and treatment outcome for women with choriocarcinoma after a nonmolar pregnancy.

DESIGN

Retrospective analysis of case records between 1985 and 1994.

SETTING

A referral centre for trophoblastic disease.

SUBJECTS

One hundred women with choriocarcinoma: 62 after a live birth, six after a live birth preceded by a molar pregnancy and 32 after a nonmolar abortion.

RESULTS

Choriocarcinoma after nonmolar pregnancies represent 17% of the total gestational trophoblastic tumours requiring treatment. Vaginal bleeding was the commonest symptom in all groups, but symptoms from metastatic disease were important in the group presenting after a live birth. Metastatic disease was present in 31% of cases after live birth and 43% post-abortion. The median interval between the antecedent pregnancy and choriocarcinoma was five and six months, respectively. High risk multi-agent chemotherapy was required in 82% and 60% of cases, respectively. The mortality rate was significantly higher after a live birth than a nonmolar abortion (21% vs 6%).

CONCLUSIONS

Treatment of choriocarcinoma after a live birth is associated with an unacceptably high mortality rate. Vaginal bleeding is an important early symptom and a pregnancy test should be performed if it persists after usual medical treatment.

Isolation of small, primitive human hematopoietic stem cells: distribution of cell surface cytokine receptors and growth in SCID-Hu mice

Human CD34+ cells were subfractionated into three size classes using counterflow centrifugal elutriation followed by immunoadsorption to polystyrene cell separation devices. The three CD34+ cell fractions (Fr), Fr 25/29, Fr 33/37, and Fr RO, had mean sizes of 8.5, 9.3 and 13.5 microns, respectively. The majority of cells in the large Fr RO CD34+ cell population expressed the committed stage antigens CD33, CD19, CD38, or HLA-DR and contained the majority of granulocyte-macrophage colony-forming units (CFU-GM), burst-forming units-erythroid (BFU-E), and CFU-mixed lineage (GEMM). In contrast, the small Fr 25/29 CD34+ cells were devoid of committed cell surface antigens and lacked colony-forming activity. When seeded to allogeneic stroma, Fr RO CD34+ cells produced few CFU-GM at week 5, whereas cells from the Fr 25/29 CD34+ cell population showed a 30- to 55-fold expansion of myeloid progenitors at this same time point. Furthermore, CD34+ cells from each size fraction supported ontogeny of T cells in human thymus/liver grafts in severe combined immunodeficient (SCID) mice. Upon cell cycle analyses, greater than 97% of the Fr 25/29 CD34+ cells were in G0/G1 phase, whereas greater proportions of the two larger CD34+ cell fractions were in active cell cycle. Binding of the cytokines interleukin (IL)-1 alpha, IL-3, IL-6, stem cell factor (SCF), macrophage inhibitory protein (MIP)-1 alpha, granulocyte colony-stimulating factor (G-CSF), and granulocyte-macrophage (GM)-CSF to these CD34+ cell populations was also analyzed by flow cytometry. As compared with the larger CD34+ cell fractions, cells in the small Fr 25/29 CD34+ cell population possessed the highest numbers of receptors for SCF, MIP1 alpha, and IL-1 alpha. Collectively, these results indicate that the Fr 25/29 CD34+ cell is a very primitive, quiescent progenitor cell population possessing a high number of receptors for SCF and MIP1 alpha and capable of yielding both myeloid and lymphoid lineages when placed in appropriate in vitro or in vivo culture conditions.

Educating physicians to use the digital library

Skill in creating, finding, managing, and using biomedical information is a vital component of modern medical practice. Medical schools recognize the revolutionary implications of computing technology and use a number of different strategies to integrate "informatics education" into their curricula. In many institutions, leadership for this effort rests with the health sciences library and/or the department of medical informatics. Examples are presented of how nine medical schools have implemented informatics education; no single informatics-education strategy prevails, and these schools' strategies do not exhaust the possibilities. Informatics education programs will require better planning and integration in the future because of the need to keep pace with curriculum reform, the changing context of medical practice, and the speed of technological innovation.

The organization of the digital library

As digital information proliferates and the difficulties of managing it threaten to overwhelm traditional publication and information delivery processes, new visions of a digital library are forming. Exactly what a digital library is and how it is to be organized have not yet been determined, and bibliographic organization of digital information has not been sufficiently addressed. Bibliography is the systematic description or classification of writings or publications considered as material objects. In today's digital world, such material objects may no longer be relevant, but the need for systematic description remains. The important issue is not whether digital bibliography is needed but, instead, whether or not existing bibliographic techniques are appropriate for this new media. A second issue is the location of the responsibility for a new digital bibliography. Does it rest with medical informaticians, often the producers of this new digital information, or with librarians, traditionally the classifiers of information? Developments in both medical informatics and medical librarianship indicate a need for greater collaboration between these specialties in order to achieve their common purpose--the creation, classification, and dissemination of scholarly information.

Informatics and medical libraries: changing needs and changing roles

Medical librarians play a crucial role in the evolution of institutional information policy. As information professionals, they share many similarities with their medical informatics counterparts. Both groups emphasize information delivery to the point of decision making; both groups serve as curators of institutional knowledge bases. If the term "publication" encompasses the delivery of clinical information relevant to individuals or populations, both librarians and medical informaticians have an immediate interest in the nature of biomedical publishing, particularly in areas of intellectual ownership, confidentiality, distribution, and access. Both groups also have been early leaders in applying information technology to solve pressing knowledge-management problems, and both groups have a strong commitment to educating colleagues in the effective use of information. Although the challenges faced by librarians and medical informaticians are sometimes different, the evolution of information technology and new forms of biomedical communication suggest that there is now a greater convergence between the two disciplines.

TGF-beta 1 post-treatment in a rabbit model of cerebral ischaemia

Transforming growth factor-beta 1 (TGF-beta 1), suggested in some studies to suppress astrocyte and neutrophil function, has also reduced ischaemic brain injury when administered immediately prior to clot embolization in models of thromboembolic stroke. The effect of TGF-beta 1 as a post-treatment paradigm was investigated in a rabbit model of thromboembolic stroke. Following clot embolization, regional cerebral blood flow fell to < 10 cc 100 g-1 min-1 in all animals. TGF-beta 1 (10 micrograms) or vehicle (n = 5 each group) was infused via the contralateral carotid artery. TGF-beta 1 administration resulted in a rapid and selective reduction in the peripheral neutrophil count as compared to a significant (p < 0.05) increase in control values (2336 +/- 817 vs 4320 +/- 928 neutrophils mm3, mean +/- SEM). Neutrophil aggregation was increased within 30 min of TGF-beta 1 infusion when compared to control (2.07 +/- 0.70 vs 1.09 +/- 0.17 ohms, p < 0.05); neutrophil chemiluminescence, an index of the oxygen respiratory burst was not significantly affected by TGF-beta 1 administration. No difference in platelet counts or aggregation was noted. There was no significant difference between the two groups regarding brain infarct size (47.5 +/- 10.9 vs 56.5 +/- 10.4, n = 4, TGF-beta vs control, mean +/- SEM), intracranial pressure, or brain excitatory amino acid levels (aspartate and glutamate) within ischaemic regions.(ABSTRACT TRUNCATED AT 250 WORDS)

Decreased protein catabolism after exercise in subjects with IDDM

We examined whether the increased rates of protein catabolism (proteolysis and leucine oxidation) associated with moderate insulinopenia in subjects with IDDM would be accentuated by prior bicycle exercise (53% VO2max for 82 min). Insulin infusions maintained plasma glucose concentrations on one study day in "tight" control (TC: 6 mmol/l) and on a separate day in "loose" control (LC: 12 mmol/l). Elevations in serum ketone body, plasma NEFA, and whole-blood branched-chain amino acid concentrations on the loose control day during the basal period persisted throughout the post-exercise recovery period. Amino acid kinetics were estimated during a primed, constant infusion of L-[1-13C]leucine from plasma dilution of alpha-[1-13C]KIC and expired air 13CO2 enrichments. Loose control was associated with increased rates of whole-body leucine oxidation (LC 25 +/- 7 vs TC 21 +/- 8 mumol.kg-1.h-1) and protein degradation (LC 127 +/- 12 vs TC 118 +/- 18 mumol.kg-1.h-1) (both p < 0.05). During the 2-h post exercise recovery period, there were significant decreases in rates of leucine oxidation (LC 21 +/- 7, TC 16 +/- 7) and protein degradation (LC 112 +/- 13, TC 107 +/- 11), compared to the basal period (both p < 0.05, basal vs recovery). Rates of whole-body protein synthesis were unchanged by prior exercise. In conclusion, moderate insulinopenia is associated with significantly higher rates of protein degradation and leucine oxidation in the basal state. Following exercise, net protein catabolism is diminished due to reduced rates of protein degradation in the presence of maintained rates of protein synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Intensive care costing methodology: cost benefit analysis of mask continuous positive airway pressure for severe cardiogenic pulmonary oedema

Costing data for intensive care admissions is important, not only for unit funding, but also for cost outcome analysis of new therapies. This paper presents an intensive care episode costing methodology using the example of a cost-benefit analysis of mask CPAP for severe cardiogenic pulmonary oedema (CPO). This analysis examines the intervention of admitting all patients with severe CPO to the intensive care unit for mask CPAP, compared with the previous practice of admitting only patients failing conventional non-CPAP treatment and requiring mechanical ventilation. The episode costs were determined from a prospective study which showed mask CPAP reduced the need for mechanical ventilation from 35% to 0%. The mean cost of a mask CPAP episode was $1,156, with a mean stay of 1.2 days, compared with ventilated patients, $5,055 and 4.2 days. The major contributors to cost in both groups were nursing and medical salaries, and hospital overheads. The cost of previous estimated yearly caseload of 35 ventilated patients ($176,925) was greater than the cost associated with an increased caseload of 100 mask CPAP patients ($115,600). We conclude that, despite an increase in admissions, mask CPAP for severe CPO is cost-effective.

Designing medical informatics research and library--resource projects to increase what is learned

Careful study of medical informatics research and library-resource projects is necessary to increase the productivity of the research and development enterprise. Medical informatics research projects can present unique problems with respect to evaluation. It is not always possible to adapt directly the evaluation methods that are commonly employed in the natural and social sciences. Problems in evaluating medical informatics projects may be overcome by formulating system development work in terms of a testable hypothesis; subdividing complex projects into modules, each of which can be developed, tested and evaluated rigorously; and utilizing qualitative studies in situations where more definitive quantitative studies are impractical.

Creating the integrated information infrastructure for the 21st century at the University of Washington Warren G. Magnuson Health Sciences Center

Successful integrated information systems implementation requires an effective marriage of technology and information resources in response to critical institutional needs. The University of Washington technical infrastructure, developed over the past five years, includes ubiquitous, high-speed network access throughout the Health Sciences Center and hospitals, agreement on network standards and protocols, uniform interface to common databases (character-based and GUI) and network availability of a variety of databases and information resources at no charge to the individual. As a result of this heavy institutional investment in technical infrastructure, our implementation process will focus on expanding the number of available resources as well as developing and refining tools and services to enhance the utility of electronic information resources. Above all we will study and develop strategies for dealing with the myriad of information policy issues which confront and confound us all today.

Immunization with recombinant woodchuck hepatitis virus nucleocapsid antigen or hepatitis B virus nucleocapsid antigen protects woodchucks from woodchuck hepatitis virus infection

Woodchucks were immunized with recombinant woodchuck hepatitis virus (WHV) nucleocapsid antigen (WHcAg) or hepatitis B virus (HBV) nucleocapsid antigen (HBcAg) and challenged with 10(6) WHV ID50. Six out of six woodchucks immunized with WHcAg and four out of six immunized with HBcAg were protected from WHV infection. Woodchucks immunized with WHcAg or HBcAg developed high serum antibody titres against WHcAg or HBcAg. Antibodies against WHc and HBc displayed little cross-reactivity (< 1%). This confirms and extends previous reports of protection against homologous challenge after immunization with HBcAg/WHcAg which are both internal viral antigens. As the dominant B-cell epitope(s) on particulate WHcAg and HBcAg appear not to be conserved it also demonstrates that antibodies against HBcAg/WHcAg are not important for this protection. Woodchucks immunized with WHcAg/HBcAg reacted with a fast serum antibody response against viral envelope proteins upon challenge with WHV, indicative of functional intrastructural/intermolecular T-cell help as one potential mechanism of protection after immunization with an internal viral antigen.

From bench to bedside: research and testing of Internet resources and connections in community hospital libraries

Access to information becomes more valuable with the continuing proliferation of medical knowledge and the increasing economic pressure being experienced by health care organizations. This is particularly so for community hospitals in rural or isolated areas, where the economic pressures are at least as great as in urban areas and where access to information is often inadequate. These conditions have implications for the quality of patient care and for economic viability. In response to this, the National Library of Medicine, the University of Washington, and seven community hospitals in five Pacific Northwest states have joined forces in a broad-scale technology diffusion project to facilitate the application of research work to clinical care. There are three components to the project: 1) a pilot connections component to extend Internet access to the community hospitals, 2) a research component to test the performance of a client/server model for network access to anatomical text and images, and 3) a clinical component to develop a registry of DNA diagnostic laboratories facilitating the provision of genetic information to clinicians. The pilot connections component is described and preliminary findings are reported.