Radiologists' Diagnostic Performance in Differentiation of Rickets and Classic Metaphyseal Lesions on Radiographs: A Multicenter Study.

BACKGROUND. Despite evidence supporting the specificity of classic metaphyseal lesions (CML) for the diagnosis of child abuse, some medicolegal practitioners claim that CML result from rickets rather than trauma. OBJECTIVE. The purpose of this study was to evaluate radiologists' diagnostic performance in differentiating rickets and CML on radiographs. METHODS. This retrospective seven-center study included children younger than 2 years who underwent knee radiography from January 2007 to December 2018 and who had either rickets (25-hydroxyvitamin D level < 20 ng/mL and abnormal knee radiographs) or knee CML and a diagnosis of child abuse from a child abuse pediatrician. Additional injuries were identified through medical record review. Radiographs were cropped and zoomed to present similar depictions of the knee. Eight radiologists independently interpreted radiographs for diagnoses of rickets or CML, rated confidence levels, and recorded associated radiographic signs. RESULTS. Seventy children (27 girls, 43 boys) had rickets; 77 children (37 girls, 40 boys) had CML. Children with CML were younger than those with rickets (mean, 3.7 vs 14.2 months, p < .001; 89.6% vs 5.7% younger than 6 months; 3.9% vs 65.7% older than 1 year). All children with CML had injuries in addition to the knee CML identified at physical examination or other imaging examinations. Radiologists had almost perfect agreement for moderate- or high-confidence interpretations of rickets (κ = 0.92) and CML (κ = 0.89). Across radiologists, estimated sensitivity, specificity, and accuracy for CML for moderate- or high-confidence interpretations were 95.1%, 97.0%, and 96.0%. Accuracy was not significantly different between pediatric and nonpediatric radiologists (p = .20) or between less experienced and more experienced radiologists (p = .57). Loss of metaphyseal zone of provisional calcification, cupping, fraying, and physeal widening were more common in rickets than CML, being detected in less than 4% of children with CML. Corner fracture, bucket-handle fracture, subphyseal lucency, deformed corner, metaphyseal irregularity, and subperiosteal new bone formation were more common in CML than rickets, being detected in less than 4% of children with rickets. CONCLUSION. Radiologists had high interobserver agreement and high diagnostic performance for differentiating rickets and CML. Recognition that CML mostly occur in children younger than 6 months and are unusual in children older than 1 year may assist interpretation. CLINICAL IMPACT. Rickets and CML have distinct radiographic signs, and radiologists can reliably differentiate these two entities.

In vitro demineralization prevention by fluoride and silver nanoparticles when applied to sound enamel and enamel caries-like lesions of varying severities.

OBJECTIVES: To investigate the effect of fluoride and silver nanoparticles on the prevention of in vitro demineralization of sound enamel and enamel caries-like lesions of varying severities. METHODS: Caries-like lesions of different severities (1/6/15 days) were created in bovine enamel specimens. One group remained sound. All specimens were demineralized again using a partially saturated acetic acid solution. Mimicking the intra-oral retention of fluoride and silver in vitro, this solution was supplemented with fluoride (0/1/10 ppm) and/or silver nanoparticles (0/10 ppm) in a factorial design. Changes in lesion depth (ΔL) and integrated mineral loss (ΔΔZ) were evaluated by digital transverse microradiography. Data was analyzed using three-way ANOVA. RESULTS: Lesion severity significantly affected ΔΔZ and ΔL, after no treatment and after the treatment of fluoride and silver independently (p = 0.012 and p = 0.037, respectively). Fluoride and the fluoride × lesion severity interaction were shown to be significant (p < 0.001) on ΔΔZ and ΔL. Silver nanoparticles significantly affected ΔΔZ (p = 0.041), but not ΔL (p = 0.15). The silver nanoparticles × lesion severity interaction was significant for ΔΔZ and ΔL (p = 0.032 and p = 0.024, respectively). No interaction was observed for ΔΔZ and ΔL between fluoride and silver (p = 0.962 and p = 0.971, respectively) as well as lesion severity and the use of fluoride and silver combined (p = 0.722 and p = 0.158, respectively). CONCLUSION: Fluoride and silver nanoparticles had a significant effect on the prevention of in vitro demineralization of sound enamel and enamel caries-like lesions of varying severities. CLINICAL SIGNIFICANCE: Fluoride and silver nanoparticles may potentially allow for more tailored caries prevention.

A visual evaluation of oral plaque removal utilizing an adjunct enzyme pre-rinse in orthodontic subjects.

OBJECTIVE: To determine if an adjunct proteolytic pre-rinse along with contemporary methods of dental cleaning may more effectively remove visual plaque in subjects with fixed orthodontic appliances. MATERIALS AND METHODS: Forty-three orthodontic subjects, ages 10 to 25, completed this single site, double-blind, crossover clinical trial. Subjects randomly received bromelain enzyme or a powdered-sugar placebo pre-rinse, followed by manual tooth brushing and use of a Waterpik. Subjects received the alternate pre-rinse during the subsequent visit. Baseline and residual plaque accumulation were recorded via disclosing tablet and digital photography. A single, blinded examiner scored visual plaque scores from randomized photographs. Treatment effects on composite plaque score were evaluated using repeated-measures analysis of variance. A 5% significance level was used for all tests. RESULTS: No significant differences in plaque scores were noted at baseline or post-rinse between the enzyme and placebo. The changes from baseline to post-rinse (P = .190), post-brushing (P = .764), and post-Waterpik (P = .882) were not significantly different between interventions. Significant reduction in plaque scores were observed in both arms of the study after brushing (P < .01) and waterjet use (P < .01). Neither age (P = .220) nor gender (P = .449) impacted plaque scores. CONCLUSIONS: Use of a bromelain enzyme pre-rinse alone did not significantly enhance plaque removal. A significant reduction in retained plaque was observed with the application of brushing and or Waterpik.

Inner Engineering Practices and Advanced 4-day Isha Yoga Retreat Are Associated with Cannabimimetic Effects with Increased Endocannabinoids and Short-Term and Sustained Improvement in Mental Health: A Prospective Observational Study of Meditators.

BACKGROUND: Anxiety and depression are common in the modern world, and there is growing demand for alternative therapies such as meditation. Meditation can decrease perceived stress and increase general well-being, although the physiological mechanism is not well-characterized. Endocannabinoids (eCBs), lipid mediators associated with enhanced mood and reduced anxiety/depression, have not been previously studied as biomarkers of meditation effects. Our aim was to assess biomarkers (eCBs and brain-derived neurotrophic factor [BDNF]) and psychological parameters after a meditation retreat. METHODS: This was an observational pilot study of adults before and after the 4-day Isha Yoga Bhava Spandana Program retreat. Participants completed online surveys (before and after retreat, and 1 month later) to assess anxiety, depression, focus, well-being, and happiness through validated psychological scales. Voluntary blood sampling for biomarker studies was done before and within a day after the retreat. The biomarkers anandamide, 2-arachidonoylglycerol (2-AG), 1-arachidonoylglycerol (1-AG), docosatetraenoylethanolamide (DEA), oleoylethanolamide (OLA), and BDNF were evaluated. Primary outcomes were changes in psychological scales, as well as changes in eCBs and BDNF. RESULTS: Depression and anxiety scores decreased while focus, happiness, and positive well-being scores increased immediately after retreat from their baseline values (P < 0.001). All improvements were sustained 1 month after BSP. All major eCBs including anandamide, 2-AG, 1-AG, DEA, and BDNF increased after meditation by > 70% (P < 0.001). Increases of ≥20% in anandamide, 2-AG, 1-AG, and total AG levels after meditation from the baseline had weak correlations with changes in happiness and well-being. CONCLUSIONS: A short meditation experience improved focus, happiness, and positive well-being and reduced depression and anxiety in participants for at least 1 month. Participants had increased blood eCBs and BDNF, suggesting a role for these biomarkers in the underlying mechanism of meditation. Meditation is a simple, organic, and effective way to improve well-being and reduce depression and anxiety.

Photoinhibition of Streptococcus mutans Biofilm-Induced Lesions in Human Dentin by Violet-Blue Light.

This in vitro study determined the effectiveness of violet-blue light on Streptococcus mutans (UA159) biofilm induced dentinal lesions. Biofilm was formed on human dentin specimens in a 96-well microtiter plate and incubated for 13 h in the presence of tryptic soy broth (TSB) or TSB supplemented with 1% sucrose (TSBS). Violet-blue light (405 nm) from quantitative light-induced fluorescence (QLFTM) was used to irradiate the biofilm. Supernatant liquid was removed, and the biofilm was irradiated continuously with QLF for 5 min twice daily with an interval of 6 h for 5 d, except with one treatment on the final day. Colony forming units (CFU) of the treated biofilm, changes in fluorescence (∆F; QLF-Digital BiluminatorTM), lesion depth (L), and integrated mineral loss (∆Z; both transverse microradiography) were quantified at the end of the fifth day. Statistical analysis used analysis of variance (ANOVA), testing at a 5% significance level. In the violet-blue light irradiated groups, there was a significant reduction (p < 0.05) of bacterial viability (CFU) of S. mutans with TSB and TSBS. Violet-blue light irradiation resulted in the reduction of ∆F and L of the dentinal surface with TSBS. These results indicate that violet-blue light has the capacity to reduce S. mutans cell numbers.

Preliminary Performance of the Advanced Dental Admission Test (ADAT): Association Between ADAT Scores and Other Variables for Applicants to Residency Programs at a U.S. Dental School.

Historically, dental residency programs have used numerical assessment criteria to evaluate and identify qualified candidates for admission. Recent elimination of such assessment tools has undermined many programs' holistic evaluation process. The Advanced Dental Admission Test (ADAT) was developed and recently piloted in hopes of addressing this issue. The aim of this study was to evaluate the preliminary performance and validity of the ADAT by exploring the association between ADAT scores and other variables for a sample of applicants to residency programs. The WebAdMIT admissions database was used to identify the test scores and educational and demographic information of 92 individuals who completed the pilot ADAT and were seeking a 2017 postgraduate specialty position at Indiana University School of Dentistry. The results showed that the ADAT had strong to weak correlations with certain applicant variables (p<0.05). No significant differences were found for age, race, school location, or country of origin. However, males performed better than females (p<0.05), and non-Hispanics performed better than Hispanics (p<0.01). ADAT component scores were also higher for individuals with a history of research activity (p<0.05). This study found that significant associations existed between the ADAT and indices typically associated with competitive applicants. These findings suggest that the ADAT may serve as a useful numerical assessment instrument, with the potential to identify high-performing candidates. Furthermore, the ADAT seemed to be a plausible option for programs seeking to incorporate a quantitative assessment instrument as part of a holistic candidate selection process.

Effect of phototherapy on the metabolism of Streptococcus mutans biofilm based on a colorimetric tetrazolium assay.

The aim of this in vitro study was to determine the effect of violet-blue light on the metabolic activity of early Streptococcus mutans biofilm, reincubated at 0, 2, and 6 h after 5 min of violet-blue light treatment. S. mutans UA159 biofilm cells were cultured for 12 to 16 h in microtiter plates with Tryptic Soy broth (TSB) or TSB with 1% sucrose (TSBS) and irradiated with violet-blue light for 5 min. After irradiation, the plates were reincubated at 37°C for 0, 2, or 6 h in 5% CO2. Colorimetric tetrazolium salt reduction assay was used to investigate bacterial metabolic activity. Mixed model ANOVA was used to find the difference between the violet-blue light treated and nontreated groups. Bacterial metabolic activity was significantly lower in the violet-blue light group for TSB than in the nontreated group (P < 0.0001) regardless of recovery time. However, the differences between metabolic activity in the treated groups without sucrose decreased over time. For TSBS, metabolic activity was significantly lower with violet-blue light at 0 and 2 h. Violet-blue light inhibited the metabolic activity of S. mutans biofilm cells in the light-treated group. This finding may present a unique treatment method for patients with active caries.

Factors associated with seeking preventive dental care: an integrative model exploration of behaviors in Mexican immigrants in Midwest America.

BACKGROUND: Mexican immigrants in the United States suffer from poor oral health. The objective of the current study was to explore the utility of applying theory-based factors associated with seeking preventive dental care in a sample of Mexican American adults. METHODS: Data were collected from a cross-sectional survey of a sample of 157 people of Mexican origin (64% female; age 34 ± 11 years) recruited primarily from church congregations and lay community organizations in Central Indiana. Using the Integrative Model of Behavioral Prediction as the guiding framework, structural equation modeling was used to test factors associated with intention to seek preventive dental care. RESULTS: Attitude towards seeking preventive dental care (estimate = 0.37; p < .0001) and self-efficacy for seeking preventive dental care (estimate = 0.68; p < .0001) were associated with intention to seek preventive dental care. The association between dental beliefs and intention to seek preventive dental care was mediated by attitude and self-efficacy (indirect effect = 0.26, p = .002), and the association between past behavior and intention to seek preventive dental care was mediated by self-efficacy (indirect effect = 0.26, p = .003). CONCLUSIONS: These findings suggest that interventions to increase preventive dental care seeking behavior among Mexican Americans should focus on changing attitudes toward seeking preventive dental care and on increasing self-efficacy to seek preventive dental care. Findings also support the use of interventions to influence dental beliefs.

Effect of Violet-Blue Light on Streptococcus mutans-Induced Enamel Demineralization.

BACKGROUND: This in vitro study determined the effectiveness of violet-blue light (405 nm) on inhibiting Streptococcus mutans-induced enamel demineralization. MATERIALS AND METHODS: S. mutans UA159 biofilm was grown on human enamel specimens for 13 h in 5% CO2 at 37 °C with/without 1% sucrose. Wet biofilm was treated twice daily with violet-blue light for five minutes over five days. A six-hour reincubation was included daily between treatments excluding the final day. Biofilms were harvested and colony forming units (CFU) were quantitated. Lesion depth (L) and mineral loss (∆Z) were quantified using transverse microradiography (TMR). Quantitative light-induced fluorescence Biluminator (QLF-D) was used to determine mean fluorescence loss. Data were analyzed using one-way analysis of variance (ANOVA) to compare differences in means. RESULTS: The results demonstrated a significant reduction in CFUs between treated and non-treated groups grown with/without 1% sucrose. ∆Z was significantly reduced for specimens exposed to biofilms grown without sucrose with violet-blue light. There was only a trend on reduction of ∆Z with sucrose and with L on both groups. There were no differences in fluorescence-derived parameters between the groups. CONCLUSIONS: Within the limitations of the study, the results indicate that violet-blue light can serve as an adjunct prophylactic treatment for reducing S. mutans biofilm formation and enamel mineral loss.

Human IGF-I propeptide A promotes articular chondrocyte biosynthesis and employs glycosylation-dependent heparin binding.

BACKGROUND: Insulin-like growth factor I (IGF-I) is a key regulator of chondrogenesis, but its therapeutic application to articular cartilage damage is limited by rapid elimination from the repair site. The human IGF-I gene gives rise to three IGF-I propeptides (proIGF-IA, proIGF-IB and proIGF-IC) that are cleaved to create mature IGF-I. In this study, we elucidate the processing of IGF-I precursors by articular chondrocytes, and test the hypotheses that proIGF-I isoforms bind to heparin and regulate articular chondrocyte biosynthesis. METHODS: Human IGF-I propeptides and mutants were overexpressed in bovine articular chondrocytes. IGF-I products were characterized by ELISA, western blot and FPLC using a heparin column. The biosynthetic activity of IGF-I products on articular chondrocytes was assayed for DNA and glycosaminoglycan that the cells produced. RESULTS: Secreted IGF-I propeptides stimulated articular chondrocyte biosynthetic activity to the same degree as mature IGF-I. Of the three IGF-I propeptides, only one, proIGF-IA, strongly bound to heparin. Interestingly, heparin binding of proIGF-IA depended on N-glycosylation at Asn92 in the EA peptide. To our knowledge, this is the first demonstration that N-glycosylation determines the binding of a heparin-binding protein to heparin. CONCLUSION: The biosynthetic and heparin binding abilities of proIGF-IA, coupled with its generation of IGF-I, suggest that proIGF-IA may have therapeutic value for articular cartilage repair. GENERAL SIGNIFICANCE: These data identify human pro-insulin-like growth factor IA as a bifunctional protein. Its combined ability to bind heparin and augment chondrocyte biosynthesis makes it a promising therapeutic agent for cartilage damage due to trauma and osteoarthritis.

In Vitro Effects of Plantago Major Extract, Aucubin, and Baicalein on Candida albicans Biofilm Formation, Metabolic Activity, and Cell Surface Hydrophobicity.

PURPOSE: To determine the in vitro effectiveness of Plantago major extract, along with two of its active components, aucubin and baicalein, on the inhibition of Candida albicans growth, biofilm formation, metabolic activity, and cell surface hydrophobicity. MATERIALS AND METHODS: Twofold dilutions of P. major, aucubin, and baicalein were used to determine the minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), and the minimum biofilm inhibitory concentration (MBIC) of each solution. Separately, twofold dilutions of P. major, aucubin, and baicalein were used to determine the metabolic activity of established C. albicans biofilm using a 2,3-bis (2- methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-carboxanilide reduction assay. Twofold dilutions of P. major, aucubin, and baicalein were used to determine the cell surface hydrophobicity of treated C. albicans biofilm by a two-phase assay using hexadecane. The hydrophobicity percentage of the cell surface was then calculated. A mixed-model ANOVA test was used for intergroup comparisons. RESULTS: The MICs of P. major extract (diluted 1:2 to 1:8), aucubin (61 to 244 µg/ml), and baicalein (0.0063 to 100 µg/ml) on the total growth of C. albicans were noticeable at their highest concentrations, and the inhibition was dose dependent. The MFC was evaluated after 48 hours of incubation, and aucubin (244 µg/ml) exhibited a strong fungicidal activity at its highest concentration against C. albicans growth. The MBIC indicated no growth or reduced growth of C. albicans biofilm at the highest concentrations of aucubin (61 to 244 µg/ml) and baicalein (25 to 100 µg/ml). Similarly, the effects of these reagents on C. albicans biofilm metabolic activity and hydrophobicity demonstrated high effectiveness at their highest concentrations. CONCLUSION: P. major extract, aucubin, and baicalein caused a dose-dependent reduction on the total growth, biofilm formation, metabolic activity, and cell surface hydrophobicity of C. albicans. This demonstrates their effectiveness as antifungals and suggests their promising potential use as solutions for C. albicans biofilm-related infections.

Novel in-situ longitudinal model for the study of dentifrices on dental erosion-abrasion.

A novel longitudinal erosion-abrasion in-situ model was proposed. In an exploratory test (phase 1) toothbrushing effect was investigated using a parallel design, whereas in the main study (phases 1 + 2), a crossover design tested the effect of fluoride dentifrice. In phase 1, 16 subjects (n = 5-6 subjects per group) wore partial dentures with enamel specimens for 28 d and adhered to one of the following treatment regimens: regimen A, erosion only; regimen B, erosion + toothbrushing with fluoride-containing dentifrice [1,100 ppm of fluoride as sodium fluoride (NaF)]; and regimen C, erosion + toothbrushing with placebo dentifrice (0 ppm fluoride). Erosion consisted of the exposure of specimens to grapefruit juice. In regimens B and C, toothbrushing was performed with the test dentifrices 5 min after erosion. For the main study a second phase was carried out in which subjects initially treated with regimen B were treated with regimen C, and vice versa (crossover, n = 11), repeating the same experimental protocol. Enamel wear was measured by optical profilometry at baseline and every 7 d thereafter. In the exploratory test (phase 1), no significant differences were observed among regimens at any of the study time-points. In the main study (phases 1 + 2), higher enamel wear was observed for regimen C than for regimen B. A significant trend was observed for the increase of enamel wear over time. Fluoridated dentifrice reduced the development of erosive-abrasive lesions. The proposed longitudinal model provided adequate responses for erosion-abrasion frequency and fluoride effects.

The effect of strontium and combinations of strontium and fluoride on the remineralization of artificial caries lesions in vitro.

OBJECTIVE: To determine the effect of relatively low strontium concentrations on enamel remineralization and investigate the dose-response effects of strontium and fluoride combinations on the remineralization of artificial caries lesions in vitro. METHOD AND MATERIALS: Artificial caries lesions were created in 135 bovine enamel specimens. Lesion severity was analyzed using transverse microradiography (TMR) and quantitative light-induced fluorescence (QLF). The specimens were randomly assigned to nine treatment groups based on lesion volume after lesion creation, as measured by TMR. Treatment groups were based on a 3 x 3 factorial design (0/0.05/0.1 ppm fluoride and 0/10/15 ppm strontium). Lesions were remineralized at 37°C for 14 days in artificial saliva, which was supplemented or not with NaF and/or SrCl2 x 6H2O. Lesion remineralization was assessed using QLF and TMR. Data were analyzed using ANOVA. RESULTS: For the TMR data, lesion remineralization in the 10 ppm strontium + 0.05 ppm fluoride group was significantly higher than in all other groups (P < .05) except the 0 ppm strontium + 0.05 ppm fluoride group (P = .06). The 10 ppm strontium + 0 ppm fluoride group exhibited significantly less remineralization than the 0 ppm strontium + 0 ppm fluoride group (P = .048). For the QLF data, intergroup differences were not the same as for the TMR analysis. The QLF measurement was only moderately correlated with TMR mineral loss (r = -0.37). CONCLUSION: Strontium alone did not improve the remineralization of artificial caries lesions under the chosen in vitro conditions. However, a synergistic effect between the combination of fluoride and strontium was found at specific concentrations.

Effect of a pulsed CO2 laser and fluoride on the prevention of enamel and dentine erosion.

OBJECTIVE: The hypotheses of this study was that pulsed CO(2) laser (lambda=10.6 microm) treatment in combination (or not) with previous fluoride gel application could increase the resistance of enamel and dentine to erosion, throughout successive erosive challenges. DESIGN: Thirty-two bovine specimens of enamel and of root dentine were flattened, polished and randomly assigned to the following treatments (n=8): fluoride (F), laser (L), fluoride+laser (FL) or no treatment as negative control (C). The treated specimens were submitted to demineralization (0.3% citric acid, pH 2.45, for 5 min) and remineralization (artificial saliva, for 60 min) cycles, three times a day, for 3 days. Dental surface loss as well as the concentration of calcium, phosphorus and fluoride in the demineralizing solutions were determined after each cycling day. Enamel and dentine were analysed separately using repeated measures ANOVA for ranks (alpha=0.05). RESULTS: The association between fluoride and laser (FL) resulted in the lowest enamel and dentine surface loss values throughout the cycles, differing significantly from the control group. No clear benefit of FL over the F or L treatments was observed. There was a non-significant trend (p>0.05) for FL to release less calcium, phosphorus and fluoride into the demineralizing solutions when compared to the other groups. CONCLUSIONS: Pulsed CO(2) laser (lambda=10.6 microm) alone was not able to prevent enamel or dentine surface losses due to erosion. Laser treatment in combination with fluoride showed some protection, but the effect does not appear to be synergistic.

Antitumor effects of 5-fluorouracil on human colon cancer cell lines: antagonism by levamisole.

BACKGROUND: The addition of levamisole (Lev) to 5-fluorouracil (5-FU) for the adjuvant treatment of stage III colon cancer has been shown to improve 5-year survival in patients. The mechanism of action of Lev remains unknown. Because we showed little in vitro immunological effect of Lev, we asked whether Lev, alone or in combination with 5-FU, had antitumor activity in vitro. METHODS: Proliferation of COLO-205 and HT-29 colon cancer cells incubated for 2 to 3 days in Lev and 5-FU was measured in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium colorimetric assays. Cell cycle analysis was performed by treating tumor cells for 6, 24, and 48 h with Lev and 5-FU, staining cells with propidium iodide, and measuring DNA content by flow cytometry. RESULTS: The addition of Lev to 5-FU did not reduce proliferation below that of 5-FU alone. The inhibitory concentration 50% (IC(50)) for 5-FU was 3.2 x 10(-6) M for COLO-205 and 1.3 x 10(-5) M for HT-29. An IC(50) was not reached for Lev, even at millimolar doses. DNA analysis of cells treated for 48 h revealed significant S-phase accumulation of both HT-29 (from 17% in control cells to 36% in treated cells) and COLO-205 (from 35% in control cells to 59% in treated cells) cell lines at micromolar 5-FU concentrations. In contrast, Lev alone did not affect cell cycle distribution for either cell line. The addition of Lev to 5-FU not only did not augment, but inhibited, the effects of 5-FU. CONCLUSIONS: Levamisole has no direct cytotoxic effect and no additive or synergistic cytotoxic effect when combined with 5-FU on two colon cancer cell lines. Either the observed clinical effects of Lev treatment occur through an as yet unknown mechanism, require longer treatment periods in vitro to become evident, or the results of clinical trials showing its effectiveness should be carefully reexamined.