Patient Perspectives on the Usefulness of an Artificial Intelligence-Assisted Symptom Checker: Cross-Sectional Survey Study.

BACKGROUND: Patients are increasingly seeking Web-based symptom checkers to obtain diagnoses. However, little is known about the characteristics of the patients who use these resources, their rationale for use, and whether they find them accurate and useful. OBJECTIVE: The study aimed to examine patients' experiences using an artificial intelligence (AI)-assisted online symptom checker. METHODS: An online survey was administered between March 2, 2018, through March 15, 2018, to US users of the Isabel Symptom Checker within 6 months of their use. User characteristics, experiences of symptom checker use, experiences discussing results with physicians, and prior personal history of experiencing a diagnostic error were collected. RESULTS: A total of 329 usable responses was obtained. The mean respondent age was 48.0 (SD 16.7) years; most were women (230/304, 75.7%) and white (271/304, 89.1%). Patients most commonly used the symptom checker to better understand the causes of their symptoms (232/304, 76.3%), followed by for deciding whether to seek care (101/304, 33.2%) or where (eg, primary or urgent care: 63/304, 20.7%), obtaining medical advice without going to a doctor (48/304, 15.8%), and understanding their diagnoses better (39/304, 12.8%). Most patients reported receiving useful information for their health problems (274/304, 90.1%), with half reporting positive health effects (154/302, 51.0%). Most patients perceived it to be useful as a diagnostic tool (253/301, 84.1%), as a tool providing insights leading them closer to correct diagnoses (231/303, 76.2%), and reported they would use it again (278/304, 91.4%). Patients who discussed findings with their physicians (103/213, 48.4%) more often felt physicians were interested (42/103, 40.8%) than not interested in learning about the tool's results (24/103, 23.3%) and more often felt physicians were open (62/103, 60.2%) than not open (21/103, 20.4%) to discussing the results. Compared with patients who had not previously experienced diagnostic errors (missed or delayed diagnoses: 123/304, 40.5%), patients who had previously experienced diagnostic errors (181/304, 59.5%) were more likely to use the symptom checker to determine where they should seek care (15/123, 12.2% vs 48/181, 26.5%; P=.002), but they less often felt that physicians were interested in discussing the tool's results (20/34, 59% vs 22/69, 32%; P=.04). CONCLUSIONS: Despite ongoing concerns about symptom checker accuracy, a large patient-user group perceived an AI-assisted symptom checker as useful for diagnosis. Formal validation studies evaluating symptom checker accuracy and effectiveness in real-world practice could provide additional useful information about their benefit.

Thermal singularity and contact line motion in pool boiling: Effects of substrate wettability.

The dynamic van der Waals theory [Phys. Rev. E 75, 036304 (2007)] is employed to model the growth of a single vapor bubble in a superheated liquid on a flat homogeneous substrate. The bubble spreading dynamics in the pool boiling regime has been numerically investigated for one-component van der Waals fluids close to the critical point, with a focus on the effect of the substrate wettability on bubble growth and contact line motion. The substrate wettability is found to control the apparent contact angle and the rate of bubble growth (the rate of total evaporation), through which the contact line speed is determined. An approximate expression is derived for the contact line speed, showing good agreement with the simulation results. This demonstrates that the contact line speed is primarily governed by (1) the circular shape of interface (for slow bubble growth), (2) the constant apparent contact angle, and (3) the constant bubble growth rate. It follows that the contact line speed has a sensitive dependence on the substrate wettability via the apparent contact angle which also determines the bubble growth rate. Compared to hydrophilic surfaces, hydrophobic surfaces give rise to a thinner shape of bubble and a higher rate of total evaporation, which combine to result in a much faster contact line speed. This can be linked to the earlier formation of a vapor film and hence the onset of boiling crisis.

Microchip isoelectric focusing using a miniature scanning detection system.

A miniature scanning fluorescent detector has been developed for plastic microchannel isoelectric focusing (mIEF) analysis. The detector, comprised of a lamp and photomultiplier tube (PMT) on a moving stage, measured the real-time distribution of fluorescently labeled peptides subjected to gel-free mIEF. During the run, the effective length of the 6-cm channel was scanned every 9 s. Analysis was completed within 5 min while still obtaining high resolution and sensitivity. In addition, the scanning detector was used to characterize peptide migration properties within the channel by providing simultaneous temporal and spatial measurements.

Lysing bacterial spores by sonication through a flexible interface in a microfluidic system.

Cell disruptions using ultrasonic energy transmitted through a flexible interface into a liquid region has limitations because the motion of the vibrating tip is not completely transferred into the liquid. To ensure that some degree of contact will be maintained between the ultrasonic horn tip and the flexible interface, the liquid must be pressurized. The pressure conditions that yield consistent coupling between the ultrasonic horn tip and the liquid region were explored in this study by using an analytical model of the system and test fixture experiments. The nature of the interaction between the horn tip and the flexible interface creates pulses of positive pressure rises, increase in temperature, streaming flow, and almost no cavitation in the liquid. There was sufficient energy to create a cloud of microspheres, or beads, that maintain a consistent pattern of ballistic motion in the liquid. The sonication was found to be repeatable by studying video recordings of bead motion and was shown to be statistically consistent using measurements of temperature rise. Sonication of bacterial spores to obtain measurements of released nucleic acid and SEM images of damaged spores were used to verify the effects of liquid pressure on the horn-interface-liquid coupling.

Sulindac sulfone inhibits K-ras-dependent cyclooxygenase-2 expression in human colon cancer cells.

Both the sulfide and sulfone metabolites of sulindac, a nonsteroidal anti-inflammatory drug, display anticarcinogenic effects in experimental models. Sulindac sulfide inhibits cyclooxygenase (COX) enzyme activities and has been reported to suppress ras-dependent signaling. However, the mechanisms by which sulindac sulfone suppresses cancer growth are not as defined. We studied the effects of these sulindac metabolites in human colon cancer-derived Caco-2 cells that have been transfected with an activated K-ras oncogene. Stable transfected clones expressed high levels of COX-2 mRNA and protein, compared with parental cells. K-ras-transfected cells formed tumors more quickly when injected into severe combined immunodeficiency disease mice than parental cells, and this tumorigenesis was suppressed by treatment with sulindac. Sulindac sulfone inhibited COX-2 protein expression, which resulted in a decrease in prostaglandin synthase E2 production. Sulindac sulfide had little effect on COX-2 in this model, but did suppress prostaglandin synthase E2 production, presumably by inhibiting COX enzyme activity. These data indicate that the sulfide and sulfone derivatives of sulindac exert COX-dependent effects by distinct mechanisms.

Allosteric modulation of [(3)H]gabapentin binding by ruthenium red.

Gabapentin is an anticonvulsant with an unknown mechanism of action. However, it has been proposed that gabapentin acts by binding to voltage-gated calcium channels. To further characterize the interaction of gabapentin with its endogenous binding site in cerebral cortex, we tested for competitive and allosteric interactions between [(3)H]gabapentin and a variety of calcium channel binding ligands. Most ligands for voltage- or ligand-gated calcium channels (verapamil, the omega-conotoxins MVIIC and GVIA, ryanodine, caffeine, capsaicin, MK-801) had no significant effect on [(3)H]gabapentin binding. However, ruthenium red, a relatively nonselective calcium channel ligand, was found to robustly modulate [(3)H]gabapentin binding. Ruthenium red slowed the association and dissociation kinetics of [(3)H]gabapentin while increasing the number of detectable binding sites. Spermine and MgCl(2), which also bind to calcium channels and modulate [(3)H]gabapentin binding, were found to act in a similar manner. These findings support the contention that the principal endogenous binding site for gabapentin is a calcium channel; they characterize the nature of the allosteric interaction of spermine, MgCl(2) and ruthenium red with this binding site; and they suggest possible mechanisms by which gabapentin may modulate calcium channel function and ultimately produce therapeutic actions.

Molecular weight-dependent paracellular transport of fluorescent model compounds induced by palmitoylcarnitine chloride across the human intestinal epithelial cell line Caco-2.

Long-chain acylcarnitines, such as palmitoylcarnitine chloride (PCC), are endogenous compounds which have been shown to increase intestinal transport of small hydrophilic compounds (including some pharmaceutical agents) through the paracellular pathway. However, the size range of the compounds whose absorption can be improved by PCC has not been fully investigated. In the present study, we systematically examined the effect of PCC on the transport rate of a series of hydrophilic fluorescent model compounds of varying molecular weights (0.3-71.2 kD) across cultured monolayers of the human intestinal epithelial cells Caco-2. Mucosal addition of 100 or 200 microM PCC resulted in comparable time-dependent decreases in the transepithelial electric resistance (T1/2, approximately 15 min). PCC addition induced a striking increase in the transport of sodium fluorescein (Flu-Na; 0.3 kD) and a slight or moderate increase in transports of fluorescent compounds of 0.6-11 kD. The effect of PCC on transport of compounds with molecular weights of > or = 17 kD appeared to be negligible. Examination by confocal laser scanning microscopy clearly revealed dilated paracellular spaces in Caco-2 monolayers which had been mucosally pretreated with PCC, confirming that PCC increases intestinal permeability by opening a paracellular transport pathway. Our results suggest that PCC is particularly effective in enhancing intestinal absorption of small hydrophilic compound like Flu-Na and may also have limited use in promoting the transport of compounds of < or = 10 kD.

Comparison between cefprozil and penicillin to eradicate pharyngeal colonization of group A beta-hemolytic streptococci.

BACKGROUND: Our objective was to perform a prospective, randomized, double blinded study of cefprozil and penicillin therapy to eradicate group A beta-hemolytic streptococci (GABHS) in children who were bacteriologic failures after receiving a standard 10-day course of penicillin treatment for GABHS pharyngitis. METHODS: Children and adolescents 2 to 18 years of age were eligible for the study. From 3 to 7 days after completing oral penicillin therapy for pharyngitis caused by GABHS, the study was explained, informed consent was obtained, a history and physical examination were completed and a throat culture was performed. Children with throat cultures positive for GABHS were randomized to receive either cefprozil or penicillin for 10 days. Children who were bacteriologic failures after administration of the first study drug were crossed over to receive the alternate drug. RESULTS: Of 180 enrolled children 66 (37%) had throat cultures positive for GABHS. Seventeen were excluded from the study, leaving 49 who completed the protocol. Of the 49 participants 26 received cefprozil initially whereas 23 received penicillin. GABHS were eradicated from the pharynx of 73% of children who received cefprozil as the first antibiotic compared with 39% of penicillin recipients (chi square, 5.748, 0.01 < P < 0.025). After crossover of failures, the final efficacy rate for cefprozil was 65% compared with 36.7% for penicillin (chi square, 5.523, 0.01 < P < 0.025). CONCLUSIONS: Cefprozil was more effective than penicillin in treating children who were bacteriologic failures after a standard 10-day course of oral penicillin.

The epidemiology of fractured femurs and the effect of these factors on outcome.

We have analysed 250 cases of fractured shaft of the femur with the objective of highlighting any preventative measures and anticipating morbidity associated with cause and type of injury. The younger patients typically injure themselves as pedestrians, motorcyclists and bicyclists in Summer. The older patients tend to have falls in late Summer and Winter. The outcome varies depending on the cause, type and age of the injured person. The greatest morbidity was found in high-velocity accidents involving motorcyclists, pedestrians and car accidents. Knee flexion is a particular problem with these injuries and we are currently using continuous passive motion in conjunction with a continuous opiate infusion where this is likely to be a problem. The results also suggest that the mechanism of injury and its possible prevention, particularly in motorcycle design, could be as important as the type of treatment. Elderly females following falls also form a distinct group, suggesting that osteoporosis is a major factor with the best outcome associated with treatment by internal fixation. We feel that age alone should not be a reason for exclusion from intramedullary fixation and this merits further study.

Injuries associated with a fractured shaft of the femur.

A knowledge of injury patterns, both from the mechanism of injury and from their associations, allows specific injuries to be suspected and actively excluded. We have reviewed fractures of the femoral shaft to highlight the patterns of their associated high morbidity and mortality. Our survey shows that accidents involving motorcyclists, pedestrians and motor cars have the highest incidence of associated injury. Common associations include chest, head, pelvis and ipsilateral leg injuries in pedestrians, and pelvic and ipsilateral leg injuries in motorcyclists. Rarer associations with femoral shaft fractures include ipsilateral tibia and talus/navicular fractures in motorcyclists, knee injuries and contralateral acetabular fractures in pedestrians and contralateral necks of femur in motor car passengers.

Galvanic reactions between cerclage wires and Kuntscher nails.

Four patients are presented who had closed femoral shaft fractures and developed either extensive callus or osteomyelitis following open Kuntscher nailing and cerclage wiring of a butterfly fragment. Both the Kuntscher nail and cerclage wire are made of stainless steel but with different percentages of constituent elements. We looked at the galvanic reactions between the two and showed potential differences of up to 4.5 m.v. in wound drainage fluid. Potential differences in this range have been reported in other studies to be associated with extensive callus and infections associated with stainless steel anode corrosion.

T3 and T4 carcinoma of the larynx--a retrospective study.

T3 and T4 lesions of the larynx were reviewed and the five year survival figures compared for radiotherapy, surgery, and combined therapy. Glottic T3N0M0 lesions gave an acceptable five year survival figure of 66 per cent. Radiotherapy is advised as the modality of treatment for T3N0M0 lesions. Larger glottic and supraglottic lesions responded poorly to all modalities of treatment and a more aggressive treatment policy may be advisable.

Avitene -- its value in the control of anterior epistaxis.

Microfibrillar collagen (Avitene) was used on a series of 61 consecutive patients with anterior epistaxis. Avitene controlled bleeding in 38 of 49 patients with idiopathic epistaxis (77 per cent). Initial control of bleeding was obtained in two out of two patients with hereditary telangiectasia, two out of three patients with septal perforations, and two of seven patients with thrombocytopenia. Overall bleeding was initially controlled in 44 of 61 patients (72 per cent) while 17 patients (28 per cent) required packing or cautery. The morbidity with Avitene is minimal. Mucosal healing is rapid, and since approximately 10 patients can be treated with one gram of the material, the cost is low. It is suggested as a simple, effective form of treatment for anterior epistaxis that emergency room and family physicians can use.