A randomized controlled trial of concept based indexing of Web page content

OBJECTIVE

Medical information is increasingly being presented in a web-enabled format. Medical journals, guidelines, and textbooks are all accessible in a web-based format. It would be desirable to link these reference sources to the electronic medical record to provide education, to facilitate guideline implementation and usage and for decision support. In order for these rich information sources to be accessed via the medical record they will need to be indexed by a single comparable underlying reference terminology.

METHODS

We took a random sample of 100 web pages out of the 6,000 web pages on the Mayo Clinic's Health Oasis web site. The web pages were divided into four datasets each containing 25 pages. These were humanly reviewed by four clinicians to identify all of the health concepts present (R1DA, R2DB, R3DC, R4DD). The web pages were simultaneously indexed using the SNOMED-RT beta release. The indexing engine has been previously described and validated. A new clinician reviewed the indexed web pages to determine the accuracy of the automated mappings as compared with the human identified concepts (R4DA, R3DB, R2DC, R1DD).

RESULTS

This review found 13,220 health concepts. Of these 10,383 concepts were identified by the initial human review (78.5% +/- 3.6%). The automated process identified 10,083 concepts correctly (76.3% +/- 4.0%) from within this corpus. The computer identified 2,420 concepts, which were not identified by the clinician's review but were upon further consideration important to include as health concepts. There was on average a 17.1% +/- 3.5% variability in the human reviewers ability to identify the important health concepts within web page content. Concept Based Indexing provided a positive predictive value (PPV) of finding a health concept of 79.3% as compared with keyword indexing which only has a PPV of 33.7% (p < 0.001).

CONCLUSION

SNOMED-RT is a reasonable ontology for web page indexing. Concept based indexing provides a significantly greater accuracy in identifying health concepts when compared with keyword indexing.

Characterization of a WaaF (RfaF) homolog expressed by Haemophilus ducreyi

Haemophilus ducreyi lipooligosaccharide (LOS) is capable of inducing an inflammatory response in skin (A. A. Campagnari, L. M. Wild, G. Griffiths, R. J. Karalus, M. A. Wirth, and S. M. Spinola, Infect. Immun. 59:2601-2608, 1991) and likely contributes to the virulence of this sexually transmitted pathogen (B. A. Bauer, M. K. Stevens, and E. J. Hansen, Infect. Immun. 68:4290-4298, 1998). An open reading frame in H. ducreyi 35000 was found to encode a predicted protein that was 59% identical to the protein product of the rfaF (waaF) gene of Salmonella typhimurium. The H. ducreyi waaF gene was able to complement an S. typhimurium rfaF (waaF) mutant, a result which confirmed the identity of this gene. In contrast to the rfaF (waaF) gene of enteric bacteria, the H. ducreyi waaF gene was not located adjacent to other genes involved in lipopolysaccharide expression. Inactivation of the H. ducreyi waaF gene by insertion mutagenesis resulted in expression of a LOS that migrated much faster than wild-type LOS in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The LOS of this mutant also did not bind a monoclonal antibody directed against a cell surface-exposed epitope of wild-type H. ducreyi LOS. Testing of the wild-type H. ducreyi strain and its isogenic waaF mutant in the temperature-dependent rabbit model for dermal lesion production by H. ducreyi revealed that this waaF mutant was less virulent than the wild-type parent strain. Complementation of the H. ducreyi waaF mutant with the wild-type H. ducreyi waaF gene resulted in expression of both wild-type LOS and wild-type virulence by this mutant.

A randomized double-blind controlled trial of automated term dissection

OBJECTIVE

To compare the accuracy of an automated mechanism for term dissection to represent the semantic dependencies within a compositional expression, with the accuracy of a practicing Internist to perform this same task. We also compare the results of four evaluators to determine the inter-observer variability and the variance between term sets, with respect to the accuracy of the mappings and the consistency of the failure analysis.

METHODS

500 terms, which required a compositional expression to effect an exact match, were randomly distributed into two sets of 250 terms (Set A and Set B). Set A was dissected using the Automated Term Dissection (ATD) Algorithm. A physician specializing in Internal Medicine dissected set B. He had no prior knowledge of the dissection algorithm or how it functioned. In this manuscript, the authors use Human Term Dissection (HTD) to refer to this method. Set A was randomized to two sets of 125 terms (Set A1 and Set A2). Set B was randomized to two sets of 125 terms (Set B1 and Set B2). A new set of 250 terms Set C was created from Set A1 and Set B2. A second new set of 250 terms Set D was created from Set A2 and Set B1. Two expert Indexers reviewed Set C and another two expert Indexers reviewed Set D. They were blinded to which terms were dissected by the clinician and which terms were dissected by the automated term dissection algorithm. The person providing the files for review to the Indexers was also unaware of which terms were dissected by ATD vs. the HTD method. The Indexers recorded whether or not the dissection was the best possible representation of the input concept. If not, a failure analysis was conducted. They recorded whether or not the dissection was in error and if so was a modifier not subsumed or was a Kernel concept subsumed when it should not have been. If a concept was missing, the Indexers recorded whether it was a Kernel concept, a modifier, a qualifier or a negative qualifier.

RESULTS

The ATD method was judged to be accurate and readable in 265 out of the 424 terms with adequate content (62.7%). The HTD method was judged to be accurate in 272 out of 414 terms with adequate content (65.7%). There was no statistically significant difference between the rates of acceptability of the ATD and HTD methods (p = 0.33). There was a non-significant trend toward greater acceptability of the ATD method in the subgroup of terms with three or more compositional elements. ATD was acceptable in 53.6% of the terms where the HTD was only acceptable in 43.6% (p = 0.11). The failure analysis showed that both methods misrepresented kernel concepts and modifiers much more commonly than qualifiers (p < 0.001).

CONCLUSIONS

There is no statistically significant difference in the accuracy and readability of terms dissected using the automated term dissection method when compared with human term dissection, as judged by four expert medical indexers. There is a non-significant trend toward improved performance of the ATD method in the subset of more complex terms. The authors submit that this may be due to a tendency for users to be less compulsive when the time to complete the task is long. Automated term dissection is a useful and perhaps preferable method for representing readable and accurate compound terminological expressions.

Involvement of the Haemophilus ducreyi gmhA gene product in lipooligosaccharide expression and virulence

The lipooligosaccharide (LOS) present in the outer membrane of Haemophilus ducreyi is likely a virulence factor for this sexually transmitted pathogen. An open reading frame in H. ducreyi 35000 was found to encode a predicted protein that had 87% identity with the protein product of the gmhA (isn) gene of Haemophilus influenzae. In H. influenzae type b, inactivation of the gmhA gene caused the synthesis of a significantly truncated LOS which possessed only lipid A and a single 2-keto-3-deoxyoctulosonic acid molecule (A. Preston, D. J. Maskell, A. Johnson, and E. R. Moxon, J. Bacteriol. 178:396-402, 1996). The H. ducreyi gmhA gene was able to complement a gmhA-deficient Escherichia coli strain, a result which confirmed the identity of this gene. When the gmhA gene of H. ducreyi was inactivated by insertion of a cat cartridge, the resultant H. ducreyi gmhA mutant, 35000.252, expressed a LOS that migrated much faster than wild-type LOS in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. When the wild-type H. ducreyi strain and its isogenic gmhA mutant were used in the temperature-dependent rabbit model for dermal lesion production by H. ducreyi, the gmhA mutant was found to be substantially less virulent than the wild-type parent strain. The H. ducreyi gmhA gene was amplified by PCR from the H. ducreyi chromosome and cloned into the pLS88 vector. When the H. ducreyi gmhA gene was present in trans in gmhA mutant 35000.252, expression of the gmhA gene product restored the virulence of this mutant to wild-type levels. These results indicate that the gmhA gene product of H. ducreyi is essential for the expression of wild-type LOS by this pathogen.

Incidence and outcomes of asthma in the elderly. A population-based study in Rochester, Minnesota

STUDY OBJECTIVE

To estimate the incidence of asthma in an elderly population and to describe the clinical characteristics, use of health services, and long-term survival of persons with onset of asthma after age 65 years.

DESIGN

Retrospective cohort study.

SETTING

Rochester, Minn.

PATIENTS

All Rochester, Minn, residents age 65 years or older who met criteria for onset of definite or probable asthma from 1964 through 1983.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Ninety-eight Rochester residents (52 female, 46 male) with onset of asthma at or after age 65 years were identified. The age- and sex-adjusted incidence was 95/100,000 (95% confidence interval, 76 to 115/100,000). The age-specific incidence of asthma was 103/100,000 in residents aged 65 to 74 years, 81/100,000 in those aged 75 to 84 years, and 58/100,000 in residents older than 85 years. Only 11% had allergy skin tests, 24% had at least one office peak flow measurement, and 43% had at least one spirometry measurement. After the diagnosis of asthma, 40% had unscheduled ambulatory visits, 22% had emergency department visits, and 42% had at least one hospitalization for asthma. Observed survival was not significantly different from expected survival.

CONCLUSIONS

Asthma is common in the elderly. Diagnostic evaluation was less intensive than present guidelines recommend. Following the diagnosis of asthma, a substantial proportion of these individuals required unscheduled ambulatory visits, emergency department visits, or hospitalizations. Asthma with onset after age 65 years was not associated with reduced survival.

Secretion of gelatinases and tissue inhibitors of metalloproteinases by human lung cancer cell lines and revertant cell lines: not an invariant correlation with metastasis

Numerous studies have reported a correlation between production of 72-kDa (MMP-2) and 92-kDa (MMP-9) type-IV collagenases/gelatinases and the metastatic potential of cancer cells. An abrogating effect of tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) on metastases has also been noted. In this report we have used sensitive enzyme-linked immunoassays to measure MMP-2, MMP-9, TIMP-1 and TIMP-2 levels in eight human lung-cancer cell lines which were characterized for biological behavior in nude mice. We demonstrated that the Calu-6 and A549 cell lines with the highest metastatic, invasive and tumorigenic potential secreted the highest levels of MMP-2. MMP-9 and TIMP-1 secretions were comparatively low in all cell lines. TIMP-2 secretion, which exceeded MMP-2 secretion for all cell lines, did not correlate with metastatic potential. To further explore these correlations, the metastatic Calu-6 cell line was transfected with a K-rev-1 cDNA expression construct. The K-rev revertant cell lines demonstrated a more differentiated phenotype and were less tumorigenic, invasive and metastatic in nude mice. Nonetheless, the Calu-6 revertant cell lines secreted higher levels of MMP-2 than the parent cell line. In conclusion, invasion and metastasis by lung-cancer cells requires not only enhanced MMP production, but also other less well-understood tumorigenic characteristics. The multiplicity of factors required by cancer cells for dissemination helps to explain the minute fraction of cancer cells from a primary tumor that ever develop into a metastasis.

Exercise training and responsiveness of isolated coronary arteries

Exercise is associated with release of catecholamines and vasoactive intestinal polypeptides. Recurrent exposure to catecholamines modifies the sensitivity of adrenoceptors. To test the hypothesis that exercise training may affect the sensitivity of the epicardial coronary arteries, we performed studies on isolated coronary arteries from male dogs capable of running on a treadmill. The animals were separated randomly into two groups: sedentary and exercise training. After 11 wk, rings of left circumflex and left anterior descending coronary arteries were studied in vitro. Contractions to alpha 1-adrenergic agonists (norepinephrine and phenylephrine) were not affected by exercise training. During contractions with prostaglandin F2 alpha, endothelium-dependent relaxations to alpha 2-adrenergic agonists (norepinephrine and UK 14304) were not reduced significantly by exercise training. The concentration-relaxation curves to beta-adrenergic agonists (norepinephrine, isoproterenol, and epinephrine) were shifted to the right after training. The concentration-response curves to vasoactive intestinal polypeptide, but not that to substance P, were shifted to the right in rings with endothelium from exercise-trained animals. These findings demonstrate a decrease in responsiveness of canine vascular smooth muscle to beta-adrenergic agonists and to vasoactive intestinal polypeptide after exercise training.

What stimulates atrial natriuretic factor release during exercise?

Prior studies have shown that circulating atrial natriuretic factor (ANF) increases during short-term exercise, but the mechanism controlling ANF release, as well as the effect of exercise training on ANF release, remains unclear. Fifteen healthy mongrel dogs underwent short-term exercise testing before and after a 12-week period of exercise training (n = 8) or cage confinement (n = 7). ANF, norepinephrine, epinephrine, right atrial pressure, and heart rate were measured simultaneously at rest and during exercise at the time of each acute exercise study. Data were analyzed for all animals with normal baseline ANF values. Exercise training had no modulating effect on circulating ANF levels at rest or during exercise. Therefore, data before and after exercise training or cage confinement were grouped (n = 24) to determine the effects of short-term exercise. ANF levels increased from 49 +/- 2 pg/ml at rest to 60 +/- 4 pg/ml during exercise (p less than 0.05). Heart rate, norepinephrine, and epinephrine values also increased, but right atrial pressure actually decreased from 2.3 +/- 0.9 mm Hg at rest to -3.8 +/- 0.9 mm Hg during exercise (p less than 0.05). There was no correlation between ANF concentrations and levels of these other variables either at rest of during exercise. By demonstrating an increase in ANF with a simultaneous decrease in right atrial pressure, this study clearly shows that increased right atrial pressure is not the secretory stimulus for ANF release during exercise in the normal dog. The lack of correlation between ANF and right atrial pressure, heart rate, norepinephrine, and epinephrine levels suggests that factors other than these variables stimulate ANF release during short-term exercise.

Exercise training produces changes in free and conjugated catecholamines

In dogs the concentrations of conjugated dopamine in plasma have previously been shown to increase after exercise training. This study was done to determine whether conjugated norepinephrine and epinephrine also increase. Fifteen dogs were randomly divided into training (N = 8) or sedentary (N = 7) groups. All dogs were exercised acutely for 5 min at 4 mph with a 12% grade, following a 3-min warm-up, before and after either a 12-wk training or a 12-wk sedentary period. Free and conjugated catecholamines were determined in blood drawn at rest and during acute exercise using high-performance liquid chromatography (HPLC) with electrochemical detection. Before training, free norepinephrine, epinephrine, dopamine, and conjugated norepinephrine increased in plasma during acute exercise. Following the 12-wk training period, there were significant increases in free and conjugated dopamine and in conjugated norepinephrine in plasma taken at rest. There were no such increases in resting catecholamines after a 12-wk sedentary period. After either training or sedentary periods, dogs responded to acute exercise with an increase in free norepinephrine and a decrease in conjugated norepinephrine. Thus, after training both conjugated norepinephrine and dopamine, but not conjugated epinephrine, increased in plasma. The data suggest that sulfation of catecholamines increases as a result of exercise training.

Does exercise training alter myocardial creatine kinase MB isoenzyme content?

Skeletal muscle biopsies from highly trained endurance athletes have been shown to contain an increased percentage of the creatine kinase MB (CK-MB) isoenzyme, which has been attributed to continuous regeneration of the skeletal muscle fibers in response to exercise-induced injury. The purpose of this study was to determine whether myocardium undergoes a similar degenerative-regenerative process as a result of exercise training. Fifteen mongrel dogs underwent a 12-wk period of training (N = 8) or cage confinement (N = 7). The animals were then sacrificed, and samples of left and right ventricular myocardium were analyzed for total CK activity and CK-MB isoenzyme content. Percentages of CK-MB were slightly but insignificantly higher from both ventricles of exercise-trained as compared with cage-confined dogs: left ventricle, 4.6 +/- 0.6% vs 3.3 +/- 0.6%, respectively (P = 0.15); right ventricle, 4.0 +/- 0.4% vs 3.0 +/- 0.8%, respectively (P = 0.29). We conclude that chronic exercise training does not induce physiologically important degenerative changes in myocardium.

Tactile-sensitive behavior in hyperactive and nonhyperactive children

The Tactile Sensitivity Behavioral Responses Checklist was used to rate behavioral responses that demonstrate tactile defensiveness by children being administered the Southern California Kinesthesia and Tactile Perception Test battery. Hypothesizing that a group of five-year-old boys with hyperactive behaviors would have greater frequencies of tactile-sensitive behaviors than a group of nonhyperactive boys, and that tactile sensitivity would be negatively correlated with tactile discrimination, videotapes of 15 hyperactive and 25 nonhyperative boys being administered the test battery were rated on the checklist. Using the Mann-Whitney U test to compare each group for behavioral response, significant results at the .05 level were reached between groups for seven out of nine categories. A significant negative correlation between tactile sensitivity and tactile discrimination was reached for those children who completed the test battery. These findings support the research hypotheses and provide a more objective data base for recognizing and further researching tactile sensitivity.

Tactile sensitivity: development of a behavioral responses checklist

Tactile defensiveness or sensitivity to being touched is a phenomenon observed by therapists during clinical testing and is reported based only on subjective data. The purpose of this study was to develop a more objective means of identifying this phenomenon. Videotaped observations of five-year-old boys being administered the Southern California Kinesthesia and Tactile Perception Test battery were used to identify behavioral reactions indicative of sensitivity to tactile stimulation. The population tested for a wide range of behaviors included hyperactive and normal five-year-old boys. These reactions were defined and categorized into a checklist of tactile-sensitive behaviroal responses. This checklist was then used on videotapes of 10 five-year-old boys by two raters to establish a measure of the reliability of this method of observing and recording behaviors. A reliability of .89 agreement with consensus was reached. These behavioral categories offer objective guides in identifying children with tactile defensiveness or sensitivity to tactile stimulation.