A Toll-like receptor-1 variant and its characteristic cellular phenotype is associated with severe malaria in Papua New Guinean children.

Genetic factors are likely to contribute to low severe malaria case fatality rates in Melanesian populations, but association studies can be underpowered and may not provide plausible mechanistic explanations if significant associations are detected. In preparation for a genome-wide association study, 29 candidate single-nucleotide polymorphisms (SNPs) with minor allele frequencies >5% were examined in a case-control study of 504 Papua New Guinean children with severe malaria. In parallel, an immunological substudy was performed on convalescent peripheral blood mononuclear cells (PBMCs) from cases and controls. Following stimulation with a Toll-like receptor (TLR) 1/2 agonist, effector cytokines and chemokines were assayed. The only significant genetic association observed involved a nonsynonymous SNP (TLR1rs4833095) in the TLR1 gene. A recessive (TT) genotype was associated with reduced odds of severe malaria of 0.52 (95% confidence interval (0.29-0.90), P=0.006). Concentrations of pro-inflammatory cytokines interleukin-1ß and tumour necrosis factor α were significantly higher in severe malaria cases compared with healthy controls, but lower in children with the protective recessive (TT) genotype. A genetic variant in TLR1 may contribute to the low severe malaria case fatality rates in this region through a reduced pro-inflammatory cellular phenotype.

The state and future of Mars polar science and exploration.

As the planet's principal cold traps, the martian polar regions have accumulated extensive mantles of ice and dust that cover individual areas of approximately 10(6) km2 and total as much as 3-4 km thick. From the scarcity of superposed craters on their surface, these layered deposits are thought to be comparatively young--preserving a record of the seasonal and climatic cycling of atmospheric CO2, H2O, and dust over the past approximately 10(5)-10(8) years. For this reason, the martian polar deposits may serve as a Rosetta Stone for understanding the geologic and climatic history of the planet--documenting variations in insolation (due to quasiperiodic oscillations in the planet's obliquity and orbital elements), volatile mass balance, atmospheric composition, dust storm activity, volcanic eruptions, large impacts, catastrophic floods, solar luminosity, supernovae, and perhaps even a record of microbial life. Beyond their scientific value, the polar regions may soon prove important for another reason--providing a valuable and accessible reservoir of water to support the long-term human exploration of Mars. In this paper we assess the current state of Mars polar research, identify the key questions that motivate the exploration of the polar regions, discuss the extent to which current missions will address these questions, and speculate about what additional capabilities and investigations may be required to address the issues that remain outstanding.

Development and validation of an exercise performance support system for people with lower extremity impairment.

OBJECTIVE: To identify innovative strategies to support appropriate, self-directed exercise that increase physical activity levels of people with arthritis. This article reports on one interactive, multimedia exercise performance support system (PSS) for people with lower extremity impairments in strength or flexibility. METHODS: An interdisciplinary team developed the PSS using self-report of lower extremity musculoskeletal impairments (flexibility and strength) to produce an individualized exercise program with video and print educational materials. Initial evaluation has investigated the validity and reliability of program assessments and recommendations. RESULTS: PSS self-report and professional assessments were similar, with more impairments indicated by self-report. PSS exercise recommendations were similar to those made by 3 expert physical therapists using the same exercise data base. Results of PSS impairment assessments were stable over a 1-week period. CONCLUSION: PSS exercise recommendations appear to be reliable and a valid reflection of current exercise knowledge in rheumatology. Furthermore, users were able to complete the computer-based program with minimal assistance and reported it to be enjoyable and informative.

Effectiveness of computer-assisted interactive videodisc instruction in teaching rheumatology to physical and occupational therapy students.

A computer-assisted interactive videodisc instructional program, HP-RHEUM was designed to teach clinical findings in arthritis to occupational and physical therapy students. Using the Rheumatology Image Library videodisc produced by the National Library of Medicine, HP-RHEUM consists of instructional modules which employ advance organizers, examples/nonexamples, summaries, and immediate feedback. To see if HP-RHEUM would be as effective as traditional classroom instruction, control data were collected in 1991 from 52 OT and PT students. Treatment data were collected from 61 students in 1992 when HP-RHEUM entirely replaced lectures. Identical pre- and post-tests consisted of 70 multiple choice questions, with 24 matched to slides. On the slide questions the HP-RHEUM group had significantly higher scores. Otherwise, there was no significant difference in performance between groups. HP-RHEUM provided an independent learning method and enhanced visual comprehension of rheumatologic disease concepts.

Transforming growth factor-beta 1 differentially regulates proliferation, morphology, and extracellular matrix expression by three neural crest-derived neuroblastoma cell lines.

We reported previously (S. L. Rogers, P. J. Gegick, S. M. Alexander, and P. G. McGuire, Dev. Biol. 151, 191-203, 1992) that transforming growth factor-beta 1 (TGF beta 1) inhibited proliferation, up-regulated fibronectin synthesis, and suppressed melanogenesis in a population of quail neural crest cells in vitro. Here, we report that cell lines derived from the parent SK-N-SH neuroblastoma line (R. A. Ross, B. A. Spengler, and J. L. Biedler, J. Natl. Cancer Inst. 71, 741-747, 1983) respond differentially to TGF beta 1, and their responses provide further insights into the actions of this growth factor on neural crest subpopulations. The SH-EP cell line exhibits primarily nonneuronal traits and responded to TGF beta 1 with increased thymidine uptake after 6 days of culture, increased expression of fibronectin mRNA and protein, and decreased laminin synthesis. Many SH-EP cells also acquired a dramatically elongated morphology, reminiscent of Schwann cells in culture. Thymidine uptake by the neuronal SY5Y cell line was not substantially altered. Neither fibronectin mRNA nor protein was detectable in either TGF beta 1-treated or untreated cultures, although laminin synthesis was upregulated by the growth factor. In TGF beta 1-treated cultures of the intermediate SH-IN cell line, which has been reported to display both neuronal and nonneuronal characteristics, there was marked flattening of many cells, a steady decrease in thymidine uptake, and increased expression of both fibronectin and laminin. The observed responses of SH-IN cells mimic those observed in primary neural crest cultures and appear to represent similar differentiation toward a mesenchymal phenotype. These results substantiate the idea that closely related but diverging neural crest-derived cell types respond selectively to TGF beta 1 and demonstrate that these SK-N-SH-derived cell lines will be useful in experimental approaches that will allow us to infer mechanisms underlying regulation of neural crest differentiation.

OA-rehab: designing a personalized exercise program for people with osteoarthritis.

We describe the design of a multi-media performance support system (PSS) based on the documented benefits of a personalized exercise program for people with arthritis, on the known value of self-efficacy and stages of change, and on principles of learning theory. The poster will show examples of incorporating motivational and cognitive principles into a PSS.

A new approach to the design of sigma-2-selective ligands: synthesis and evaluation of N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(1- pyrrolidinyl)ethylamine-related polyamines at sigma-1 and sigma-2 receptor subtypes.

A series of polyamines based on the high affinity sigma receptor ligand N-[2-(3,4-dichlorophenyl)-ethyl]-N-methyl-2-(1-pyrrolidinyl)ethylamine (3) were developed and evaluated for their binding characteristics at sigma-1 and sigma-2 receptor subtypes. The data indicated that a considerable degree of structural variation is possible while still retaining nanomolar affinity at sigma receptors. As the structure of the polyamines was varied, their binding at sigma-1 and sigma-2 subtypes showed quite different and in some cases opposite trends, supporting the belief that these are pharmacologically distinct entities. Polyamines containing two nitrogen atoms showed optimal binding at both sigma-1 and sigma-2 receptor subtypes. Although additional nitrogen atoms resulted in decreased affinity at sigma-1 and sigma-2 subtypes, an increase in selectivity for sigma-2 subtypes was evident; the parent 3 showed greater selectivity for sigma-1 subtypes. Internitrogen spacings had a large effect on binding affinity and subtype selectivity. For example, the difference between N-[3-(1-pyrrolidinyl)propyl]-N'-(3,4-dichlorobenzyl)-N,N'- dimethylethylenediamine (8) [K(i) = 29.9 nM at sigma-1 receptor and 18.3 nM at sigma-2 receptor] to N-[3-(1-pyrrolidinyl)propyl]-N'-(3,4-dichlorobenzyl)- N,N'-dimethylethylenediamine (10) [K(i) = 1.49 nM at sigma-1 receptor and 12.1 nM at sigma-2 receptor] illustrates the importance of internitrogen spacing. Triamines 11 and 13 [Ki(sigma-2)/K(i)(sigma-1) = 0.19 and 0.10, respectively] containing the N-N-N-Ar spacings 3-3-2 and 4-4-2, proved to be the most sigma-2 subtype selective of the 15 polyamines examined in this study. The N-N-N spacings appear to be an important factor in their sigma-2 subtype selectivity. These compounds will serve as templates in the design of still further sigma-2 subtype selective ligands. The pyrrolidine ring (present in most of the polyamines tested in this series) proved to be an important recognition site for sigma receptor binding activity. Furthermore, alkyl substitution also appears to be important since the stripped down polyamines N-[2-(3,4-dichlorophenyl)ethyl]ethylenediamine (15) and N1-[2-(3,4-dichlorophenyl)ethyl]diethylenetriamine (16) exhibited relatively low binding affinity.

AI/LEARN/Rheumatology. A comparative study of computer-assisted instruction for rheumatology.

OBJECTIVE: To assess the effectiveness of AI/LEARN/Rheumatology, a computer-controlled interactive videodisc system for teaching. METHODS: We assessed improvement in knowledge about rheumatic diseases, using a pretest and posttest in a control year and a treatment year. The subjects were medical students and postgraduate trainees taking the rheumatology elective. The control year used traditional lectures and the standard rheumatology curriculum. The treatment year used AI/LEARN/Rheumatology in place of lectures on rheumatoid arthritis, ankylosing spondylitis, and osteoarthritis. RESULTS: The trainees showed significant improvement in knowledge in both the control year and the treatment year (P < 0.0001 for both). The average time spent using AI/LEARN/Rheumatology was similar to the time spent in lectures (3 hours). The number of patient consultations in which trainees participated was lower in the treatment year than in the control year; however, the adjusted posttest scores using the pretest as a covariate tended to be higher in the treatment year (P = 0.10). Analysis of covariance of the adjusted posttest scores for the treatment year only showed that the trainees who spent more time using AI/LEARN/Rheumatology learned more (r = 0.57). Trainees felt that AI/LEARN/Rheumatology was the most helpful educational experience of the elective. CONCLUSION: AI/LEARN/Rheumatology is an effective means of teaching about the rheumatic diseases. It has many advantages: availability for independent study, effective use of trainee's time, and liberation of faculty time from lectures. Trainees enjoyed using AI/LEARN/Rheumatology.

GALE: a graphics assisted learning environment for computer-based interactive videodisc education.

GALE, a Graphics Assisted Learning Environment, is a computer-based interactive videodisc authoring tool. GALE was created as the authoring package for AI/LEARN/Rheumatology, an independent study system for teaching rheumatology to medical trainees. GALE has potential widespread application beyond rheumatology. Interactive videodisc technology is a prime feature of GALE. Other highlights are: WordPerfect macros which simplify programming, graphics-based large text characters, tracking of user responses, hypertext-like definition capabilities, color coded screens to distinguish between hypertext branches and the mainstream of the course content and ability to overlay text on the video image. GALE runs on a PC-compatible computer with selected Pioneer LaserDisc players. GALE uses WordPerfect 5.1 for text editing and has been designed for use by non-programmers.

Psychometric properties of the revised UCLA Loneliness Scale and two short-form measures of loneliness in Zimbabwe.

The cross-cultural reliability in Zimbabwe of the Revised University of California at Los Angeles (UCLA) Loneliness Scale and two short forms of the Revised UCLA Loneliness Scale were investigated. Subjects comprised a sample of 1,354 adolescents and another sample of 754 adults. The reliability of the Revised UCLA Loneliness Scale was acceptable. The internal consistency of an eight-item short form of the Revised UCLA Loneliness Scale was adequate, but the reliability of a four-item short form was low. Factor analysis of the Revised UCLA Loneliness Scale, which yielded two factors similar to those reported in North America by Zakahi and Duran (1982) supported the construct validity of the Revised UCLA Loneliness Scale in Zimbabwe. The Revised UCLA Loneliness Scale and the eight-item short form were highly correlated, but this association was spuriously elevated by the fact the eight-item short form is part of the full scale. Factor analysis of the eight-item short form suggested that this scale does not consistently reflect the factor structure of the full scale. We concluded that the Revised UCLA Loneliness Scale possesses acceptable reliability and factorial validity in Zimbabwe and that the eight-item version is superior to the four-item form of the Revised UCLA Loneliness Scale as a short loneliness measure. However, additional refinements may be needed to further improve the eight-item short version.

AI/Learn/Rheumatology. A computer-assisted educational system for teaching about rheumatic diseases.

Education of health professionals about the rheumatic diseases is in need of improvement. The computer is an instrument that can be used efficiently to educate large numbers of users. With specific educational principles in mind, we developed AI/Learn/Rheumatology, a computer-assisted interactive videodisc system for teaching the rheumatic diseases. While interacting with the user, it conveys knowledge using visual and problem-solving techniques. The system is efficient, enjoyable to use, and useful for small groups and independent study. It is applicable for teaching medical and allied health professional students, postgraduate trainees, and primary care physicians.

Preliminary evaluation of learning via the AI/LEARN/Rheumatology interactive videodisc system.

AI/LEARN/Rheumatology is a level three videodisc system to teach clinical observational skills in three important diseases: rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis. The AI/LEARN software was developed on an independent authoring system called GALE designed for MS-DOS based computers. The purpose of this paper is to present preliminary data about the efficacy of teaching by the use of an interactive videodisc system as evaluated by examinations centered upon disease-oriented learning objectives and by attitude questionnaires. We tested the efficacy of the AI/LEARN/Rheumatology system using both medical students and residents taking the rheumatology elective. Data collected were on learning, attitudes, and ranking of curricular elements of the rotation. We kept records on the student time and search path through the interactive videodisc system. Control data were collected during 1990, before the AI/LEARN/Rheumatology program was available. Data for the treatment groups were collected during 1991 and 1992, while the trainees used the AI/LEARN/Rheumatology system. The basic difference between the control year and the treatment year curricula was the substitution of AI/LEARN/Rheumatology for three hours of lecture covering the three target diseases. AI/LEARN/Rheumatology was as effective as traditional methods of instruction as measured by scores on a multiple choice test. Student and resident learning was related to the time spent on the system. Students and residents ranked the AI/LEARN/Rheumatology system as the single most helpful learning tool in their 8 week rheumatology block, ranking it above the examination of patients.

Isoprenoid pathway activity is required for IgE receptor-mediated, tyrosine kinase-coupled transmembrane signaling in permeabilized RBL-2H3 rat basophilic leukemia cells.

Previously, we reported that the isoprenoid pathway inhibitor, lovastatin, blocks the activation by IgE receptor cross-linking of 45Ca2+ influx, 1,4,5-inositol trisphosphate production, secretion, and membrane changes (ruffling, spreading) in intact RBL-2H3 rat basophilic leukemia cells. These results indicated that an isoprenoid pathway intermediate, very likely an isoprenylated protein, is importantly involved in the control of IgE receptor-mediated signal transduction. Here, we show that 20 h of pretreatment with lovastatin also inhibits antigen-induced secretion and membrane responses in streptolysin O-(SLO)-permeabilized cells. However, lovastatin does not inhibit secretion stimulated by the nonhydrolyzable GTP analog, GTP gamma S. Furthermore, the membrane responses to GTP gamma S persist, although in an attenuated form, in lovastatin-treated permeabilized cells. The relative insensitivity of GTP gamma S-induced responses to lovastatin was one of several indications that antigen and GTP gamma S may activate separate pathways leading to transmembrane responses in permeabilized cells. Further experiments showed that the beta-thio derivative of GDP, GDPBAS, inhibits the secretory and membrane responses to GTP gamma S, as expected for a GTP-binding protein-dependent signaling pathway, while having little effect on antigen-induced responses. Conversely, genistein blocks the secretory and membrane responses to antigen, as expected for a tyrosine kinase-dependent pathway, without altering the GTP gamma S-induced responses. From these results, and from additional data from cells treated with tyrphostins and sodium orthovanadate, we propose that IgE receptor-mediated secretion from permeabilized RBL-2H3 cells occurs by a tyrosine kinase-dependent pathway that requires isoprenoid pathway activity for function. We propose further that RBL-2H3 cells contain a separate GTP-binding protein-mediated signaling pathway whose direct activation by GTP gamma S is either independent of isoprenoid pathway activity or depends on the activity of an isoprenylated protein that is not significantly depleted after 20 h of lovastatin treatment.

Role of isoprenoid metabolism in IgE receptor-mediated signal transduction.

In the 2H3 subline of rat basophilic leukemia cells (RBL-2H3), IgE receptor cross-linking stimulates a signal transduction pathway that leads to the secretion of histamine, serotonin, and other inflammatory mediators; the assembly of F-actin; and the transformation of the cell surface from a microvillous to a lamellar or ruffled architecture. We report here that 20 h incubation of RBL-2H3 cells with 10 microM lovastatin, an inhibitor of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (HMG CoA reductase), inhibits both the secretory and morphologic responses to IgE receptor cross-linking. Ag-induced Ca2+ mobilization, determined from the influx and efflux of 45Ca2+, and Ag-induced 1,4,5-inositol trisphosphate production are also inhibited in lovastatin-treated RBL-2H3 cells. Under the same conditions, lovastatin does not alter cell proliferation or IgE receptor expression, and it causes only a small impairment of responses initiated by drugs that bypass the earliest steps in the receptor-activated transduction pathway (ionomycin-induced secretion and PMA-induced membrane ruffling). Receptor-mediated Ca2+ mobilization, secretion, and ruffling are all restored by 0.5- to 4-h incubation of lovastatin-treated cells with mevalonic acid, the product of HMG CoA reductase and the first committed intermediate of the isoprenoid biosynthetic pathway. In contrast, dolichol and cholesterol, which are synthesized from products of the isoprenoid pathway, do not restore receptor-activated responses. These data implicate an isoprenoid pathway intermediate in an early step in the IgE receptor-activated signal-transduction sequence. We postulate that this intermediate is required for a newly described post-translational modification of proteins, their post-synthetic isoprenylation. The substrates for this modification include the ras family of GTP-binding proteins and the gamma subunits of the heterotrimeric guanine nucleotide-binding protein.

Use of a microcomputer database system in a statewide effort for data collection in medical genetics.

The Genetics Office Automation System (GOAS) is a database management system for the collection and reporting of medical genetics data. We have previously reported on its implementation in a single university center [1,2]. We report here on its implementation in a coordinated data collection effort for the State of Missouri. We discuss the current status of the data collection activities and procedures to share data collected at an individual center with state, regional, and national data collection efforts.

Reversal of lovastatin-mediated inhibition of natural killer cell cytotoxicity by interleukin 2.

The activation of human natural killer (NK) cell cytotoxicity by interleukin 2 (IL-2) is well established, although the biochemical mechanisms of this stimulation have not yet been fully delineated. Earlier, we reported that treatment of NK cells with an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase such as compactin or lovastatin significantly abrogates the in vitro killing of a susceptible human erythroleukemic cell line and that this inhibition can be completely reversed by 2 hr of exposure to mevalonate (J. Cell. Physiology 139:550-557, 1989). We report here that 24 hr of treatment with IL-2 also reverses lovastatin inhibition of NK cell function. In addition to natural cytotoxicity, IL-2 also restores chemotactic and antibody dependent cellular cytotoxicity functions to lovastatin-treated cells. IL-2 does not stimulate proliferation of these cells during this time period, nor does it affect the phenotypic composition of the NK cell preparations. Although IL-2 was able to reverse the lovastatin-mediated inhibition of every cell function we examined, it had no effect on the inhibition of cholesterol biosynthesis as measured by [3H]acetate incorporation into non-saponifiable lipids, nor did it stimulate HMG CoA reductase activity. These findings support the hypothesis that there is a non-sterol isoprenoid product which is required for NK cell cytotoxicity and chemotaxis. In addition, the data suggest that IL-2 stimulation of NK cells proceeds by an isoprenoid-independent pathway.

Role of mevalonic acid in the regulation of natural killer cell cytotoxicity.

Considerable evidence has accumulated for a role of a nonsteroidal mevalonate product in the regulation of DNA replication and cell division. We report here a similar requirement for mevalonate in a nonreplicative function, that of natural killer (NK) cell cytotoxicity. Treatment of NK cells with 10 microM compactin for 48 hr results in a significant inhibition of cytotoxicity which can be completely reversed by treatment with 1 mM mevalonate, but not cholesterol, dolichol, or isopentenyl adenine. Protein and RNA synthesis appear to be involved in this reversal. Treatment with compactin and reversal with mevalonate do not affect the phenotypic distribution of the effector cell population, and the cell type involved in the inhibition and reversal of cytotoxicity is a CD16 (Leu 11)-, Leu 19-positive, large granular lymphocyte. The conjugation of the target and effector cell early in the lytic pathway is inhibited by compactin treatment of the effector cell population, and this inhibition is reversed by mevalonate.

Enteroendocrine cells in the developing opossum small intestine and colon.

Enteroendocrine cells immunoreactive for gastrin, bovine pancreatic polypeptide (BPP), glucagon (glicentin), 5-hydroxytryptamine (5-HT), somatostatin, secretin, motilin, gastric inhibitory peptide (GIP) and cholecystokinin (CCK) are scattered throughout the small intestinal epithelium of the newborn opossum and in all later postnatal stages examined. The number of BPP- and glucagon-immunoreactive cells is relatively high in the newborn and rapidly decreases until only occasional cells are present after the first postnatal week. Cells immunoreactive for GIP, CCK, 5-HT, motilin, gastrin and secretin increase in number with development. Secretin-, motilin-, CCK- and GIP-immunoreactive cells generally are concentrated proximally in the small intestine and as they increase in number, differentiate in more distal regions. The number of gastrin-immunoreactive cells actually decreases just prior to weaning but then increases at and after, weaning. Neurotensin-immunoreactive cells are unusual in that they do not appear until about the 74th postnatal day and then are first encountered in the distal small intestine. As development progresses they increase in number and appear in the more proximal regions. Cells immunoreactive for 5-HT at first increase but then decrease sharply at weaning only to increase markedly again after this time. In contrast, somatostatin-immunoreactive cells gradually decrease in number until weaning then dramatically increase. If the total number of enteroendocrine cells in the small intestine is considered, there is a gradual decrease from birth until weaning when a dramatic increase occurs. Cells immunoreactive for neurotensin, 5-HT and somatostatin are also found in the intestinal epithelium of the developing colon and caecum. Somatostatin- and 5-HT-immunoreactive cells are found throughout the colon in the newborn whereas neurotensin-immunoreactive cells, although observed initially in the proximal colon, do not form a significant population until weaning and then are concentrated distally.