Do language fluency and other socioeconomic factors influence the use of PubMed and MedlinePlus?

BACKGROUND

Increased usage of MedlinePlus by Spanish-speakers was observed after introduction of MedlinePlus in Spanish. This probably reflects increased usage of MEDLINE and PubMed by those with greater fluency in the language in which it is presented; but this has never been demonstrated in English speakers. Evidence that lack of English fluency deters international healthcare personnel from using PubMed could support the use of multi-language search tools like Babel-MeSH.

OBJECTIVES

This study aims to measure the effects of language fluency and other socioeconomic factors on PubMed MEDLINE and MedlinePlus access by international users.

METHODS

We retrospectively reviewed server pageviews of PubMed and MedlinePlus from various periods of time, and analyzed them against country statistics on language fluency, GDP, literacy rate, Internet usage, medical schools, and physicians per capita, to determine whether they were associated.

RESULTS

We found fluency in English to be positively associated with pageviews of PubMed and MedlinePlus in countries with high literacy rates. Spanish was generally found to be positively associated with pageviews of MedlinePlus en Español. The other parameters also showed varying degrees of association with pageviews.

CONCLUSIONS

After adjusting for the other factors investigated in this study, language fluency was a consistently significant predictor of the use of PubMed, MedlinePlus English and MedlinePlus en Español. This study may support the need for multi-language search tools and may increase access of health information resources from non-English speaking countries.

Usability of selected databases for low-resource clinical decision support

BACKGROUND

Smartphones are increasingly important for clinical decision support, but smartphone and Internet use are limited by cost or coverage in many settings. txt2MEDLINE provides access to published medical evidence by text messaging. Previous studies have evaluated this approach, but we found no comparisons with other tools in this format.

OBJECTIVES

To compare txt2MEDLINE with other databases for answering clinical queries by text messaging in low-resource settings.

METHODS

Using varied formats, we searched txt2MEDLINE and five other search portals (askMEDLINE, Cochrane, DynaMed, PubMed PICO, and UpToDate) to develop optimal strategies for each. We then searched each database again with five benchmark queries, using the customized search-optimization formats. We truncated the results to less than 480 characters each to simulate delivering them to a maximum of three text messages. Clinicians with practice experience in low-resource areas scored the results on a 5-point Likert scale.

RESULTS

Median scores and standard deviations from 17 reviewers were: txt2M2MEDLINE, 3.2±0.82 (control); askMEDLINE, 3.2±0.90 (p = 0.918); Cochrane, 3.8±0.58 (p = 0.073); DynaMed, 3.6±0.65 (p = 0.105); PubMed PICO, 3.6±0.82 (p = 0.005); and UpToDate, 4.0±0.52 (p = 0.002). Our sample size was sufficiently powered to find differences of 1.0 point.

CONCLUSIONS

Comparing several possible sources for texting-based clinical-decision-support information, our results did not demonstrate one-point differences in usefulness on a scale of 1 to 5. PubMed PICO and UpToDate were significantly better than txt2MEDLINE, but with relatively small improvements in Likert score (0.4 and 0.8, respectively). In a texting-only setting, txt2MEDLINE is comparable to simulated alternatives based on established reference sources.

Effects of allopurinol, erythro-9-(2-hydroxy-3-nonyl)adenine and S-(4-nitrobenzyl)-6-thioinosine on the degradation of adenosine 5'-triphosphate in the rat colon muscularis mucosae

The effects on ATP breakdown of some modulators of adenosine transport or metabolism were studied in the rat colon muscularis mucosae, a tissue which contracts to ATP and is thought to contain P2Y1 receptors. The compounds tested were the xanthine oxidase inhibitor allopurinol, the adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA) and the adenosine uptake blocker S-(4-nitrobenzyl)-6-thioinosine (NBTI). The degradation of adenosine 5'-triphosphate (ATP) (100 microM) and the appearance of metabolites was followed by high pressure liquid chromatography during incubation of isolated tissue preparations alone or in the presence of the drugs, following preincubation with the drugs for 1 h. In the absence of drugs ATP was rapidly degraded by the rat colon muscularis mucosae with a half-life of 6.1 +/- 0.7 min, the major breakdown product being inosine rather than adenosine. Allopurinol (1 microM) and NBTI (10 microM) had no effect on the rate of breakdown of ATP or on the pattern of metabolites produced. EHNA (1 or 10 microM) also had no effect on the half-life of ATP, but in the presence of EHNA (1 microM) the rate of production of inosine was significantly reduced and some adenosine was detected, while in the presence of 10 microm EHNA the production of inosine was abolished and adenosine became the final breakdown product. These results indicate that allopurinol (1 microM) and NBTI (10 microM) have no detectable effect on extracellular purine metabolism in this tissue, and that the build-up of adenosine produced by treatment with EHNA does not have a feedback effect on ATP breakdown.

Endocardial pacing, cardioversion and defibrillation using a braided endocardial lead system

The clinical efficacy and safety of a second-generation braided endocardial pacing, cardioversion and defibrillation lead system was evaluated in 25 patients with ventricular tachycardia (VT) or ventricular fibrillation (VF). The lead system consisted of two 8Fr active fixation endocardial leads each with pacing and defibrillation electrodes and a thoracic patch electrode. Monophasic and biphasic shocks were delivered using a triple-electrode configuration with a right ventricular common cathode and right atrial and thoracic patch anodes. VT and VF were electrically induced. Rapid VT (rate > or = 180 beats/min) and VF were initially terminated by 20 J (550 V) shocks and slow VT (rate < 180 beats/min) by 10 J (400 V) shocks. One hundred fourteen episodes (rapid VT/VF 73, slow VT 41) were treated with 128 shocks (monophasic 80, biphasic 48). Mean ventricular pacing threshold was 0.7 +/- 0.5 ms before and 0.9 +/- 0.5 ms after endocardial shock delivery (p > 0.2). Mean ventricular electrogram amplitude in sinus rhythm was 11.9 +/- 5.7 mV before and 11.4 +/- 5.1 mV after shock delivery (p > 0.2). Simultaneous monophasic endocardial shocks terminated 53% of VF episodes at < or = 20 J. Simultaneous biphasic shocks terminated 94% of all VF episodes at < or = 20 J (p < 0.03). Efficacy of > or = 10 J shocks for rapid VT/VF was greater for biphasic (92%) versus monophasic (74%) shocks (p < 0.05) at lower average shock energy (15 +/- 7 J vs 19 +/- 7 J, respectively, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Ventricular and atrial defibrillation using new transvenous tripolar and bipolar leads with 5 French electrodes and 8 French subcutaneous catheters

This study evaluated the use of new small transvenous atrial and ventricular leads for converting atrial fibrillation (AF) and ventricular fibrillation (VF) in 10 adult male mongrel dogs. Five dogs (group A) received a right atrial "J" (AJ) and right ventricular (RV) active fixation tripolar lead, each consisting of a platinized platinum pacing tip, anode band, and braided defibrillation electrode. The remaining five dogs (group B) received one bipolar RV lead and one tripolar AJ lead. The RV leads were implanted in the right ventricular apex (RVA) and the AJ leads were placed in the atrial appendage. Additionally all dogs received two 8 French subcutaneous defibrillation catheters in the fifth and seventh intercostal spaces. Twenty asymmetric biphasic shocks consisting of five randomized voltage levels were used to convert VF in groups A and B. The bipolar RV lead (group B) had a significantly higher probability of success in converting VF than the tripolar RV lead (group A). In group A defibrillation thresholds for converting AF were obtained using two electrode configurations. No significant difference was observed between the two electrode configurations used to convert AF. Pacing and sensing thresholds were satisfactory for bipolar and tripolar lead configuration.

The ventricular depolarization gradient: effects of exercise, pacing rate, epinephrine, and intrinsic heart rate control on the right ventricular evoked response

A new pacing technique is described that permits high fidelity recording of the paced ventricular evoked response, including cardiac depolarization. Integration of the paced R wave yields the ventricular depolarization gradient (GD), which is dependent on activation sequence and the spatial dispersion of activation times. GD was studied in 27 dogs to determine the effects of treadmill exercise at fixed rate pacing (n = 10), elevation of heart rate in the absence of stress (n = 20), epinephrine at fixed rate (n = 6), and exercise in the presence of normal chronotrophic response (n = 7). Low level exercise (1 mph, 2 min, 15 degrees) at a fixed heart rate produced significant (P less than 0.0005) decreases in GD that averaged -10.8 +/- 4.0% (mean +/- SD). The rate of change in GD was faster at the onset of exercise than at its cessation (P less than 0.0005). Artificial elevation of heart rate at rest produced significant (P less than 0.0005) increases in GD; mean sensitivity of GD to rate was 0.27 +/- 0.12%/beats/min. Intravenous injection of epinephrine produced significant (P less than 0.001) decreases in GD at two dosage levels (2.5 and 5.0 micrograms/kg) when evaluated at two baseline pacing rates (150 and 190 beats/min); mean changes in GD were -20.64 +/- 0.53% (2.5 micrograms/kg at 150 beats/min), -25.19 +/- 4.20% (5.0 micrograms/kg at 150 beats/min), -14.18 +/- 5.19% (2.5 micrograms/kg at 190 beats/min), and -24.22 +/- 4.94% (5.0 micrograms/kg at 190 beats/min). Sensitivity of GD to epinephrine was dose-dependent (P less than 0.01) at each baseline rate, but was independent (P greater than 0.05) of the rate itself. In the presence of a normal chronotropic response, GD remained unchanged (P greater than 0.5) during exercise in spite of significant elevation in heart rate (105.0 to 167.1 beats/min, P less than 0.001). These data suggest the presence of an intrinsic negative-feedback control mechanism that maintains GD constant in the healthy heart during homeostatic disturbance. Applications in closed-loop rate adaptive pacing are described.