PREDICT-GTN 1: Can we improve the FIGO scoring system in gestational trophoblastic neoplasia?

Gestational trophoblastic neoplasia (GTN) patients are treated according to the eight-variable International Federation of Gynaecology and Obstetrics (FIGO) scoring system, that aims to predict first-line single-agent chemotherapy resistance. FIGO is imperfect with one-third of low-risk patients developing disease resistance to first-line single-agent chemotherapy. We aimed to generate simplified models that improve upon FIGO. Logistic regression (LR) and multilayer perceptron (MLP) modelling (n = 4191) generated six models (M1-6). M1, all eight FIGO variables (scored data); M2, all eight FIGO variables (scored and raw data); M3, nonimaging variables (scored data); M4, nonimaging variables (scored and raw data); M5, imaging variables (scored data); and M6, pretreatment hCG (raw data) + imaging variables (scored data). Performance was compared to FIGO using true and false positive rates, positive and negative predictive values, diagnostic odds ratio, receiver operating characteristic (ROC) curves, Bland-Altman calibration plots, decision curve analysis and contingency tables. M1-6 were calibrated and outperformed FIGO on true positive rate and positive predictive value. Using LR and MLP, M1, M2 and M4 generated small improvements to the ROC curve and decision curve analysis. M3, M5 and M6 matched FIGO or performed less well. Compared to FIGO, most (excluding LR M4 and MLP M5) had significant discordance in patient classification (McNemar's test P < .05); 55-112 undertreated, 46-206 overtreated. Statistical modelling yielded only small gains over FIGO performance, arising through recategorisation of treatment-resistant patients, with a significant proportion of under/overtreatment as the available data have been used a priori to allocate primary chemotherapy. Streamlining FIGO should now be the focus.     

A short form of the Recovery Assessment Scale-Domains and Stages: Development and validation among adults with anxiety disorders

The Recovery Assessment Scale-Domains and Stages (RAS-DS) is a 38-item self-report instrument measuring recovery from serious mental illness. We explored the suitability of the RAS-DS for individuals with anxiety disorders. A parsimonious short form of the scale was developed. Participants with anxiety disorder symptoms (N = 295) completed the RAS-DS, DASS-21 and GAD-7. Confirmatory factor analysis supported the expected four-factor structure. Associations with related scales exhibited the expected pattern supporting construct validity in this population. The Recovery Assessment Scale-Short Form (RAS-SF) was derived by inspection of factor loadings and modification indices, yielding a 20-item scale with five items per subscale. Strong correlations between subscales confirmed the total score represented a valid overarching measure of recovery. The present study indicates that recovery is pertinent to individuals with anxiety disorders. Development of the short-form RAS-SF affords opportunity for routine measurement of recovery in populations with anxiety and other high prevalence conditions.     

Electrophoretic analysis of ureases in Streptococcus salivarius and in saliva

Experimental conditions were established for the extraction, electrophoresis and detection of urease isoenzymes from Streptococcus salivarius. Thiol concentrations were critical and ureases from different strains varied in ease of dissociation. A characteristic pattern was obtained for 30 ureolytic S. salivarius strains isolated from; saliva (6), dental plaque (12), artificial dental plaque (6) and non-oral sources (6), and also for a ureolytic Streptococcus bovis from artificial plaque. One non-oral S. salivarius strain had ureases with slightly slower mobility. The electrophoretic pattern and mobility of ureases extracted from human mixed salivary bacteria were identical to those from S. salivarius except for an additional set of urease bands from unknown species of bacteria. There were no ureases from saliva matching those from Staphylococcus epidermidis--a contributor to ureolysis in artificial plaque. We conclude that there is considerable biochemical homogeneity among S. salivarius ureases and possibly other ureolytic streptococci. In saliva, urea is metabolized mainly by streptococcal ureases.     

Prevalence and distribution of attached cementicles on human root surfaces

A study was undertaken to determine the prevalence and distribution of attached cementicles on different root surfaces of 415 extracted human incisors, canines, premolars and molars. The teeth were boiled in water and soaked in a 5.25% solution of sodium hypochlorite to clean the root surfaces of any soft tissue and debris. Examination with a dissecting microscope showed cementicles on 144 (34%) of the teeth. Cementicles were seen on approximately 50% of the canines and molars and on fewer than 50% of the other teeth. On canines, cementicles were found most frequently in the middle and apical thirds of the roots. On molars, cementicles were found most frequently in furcations. A relationship was noted between the presence of enamel pearls in molar furcations and enamel projections from the cementoenamel junction. The findings suggest that cementicles occur in certain locations frequently enough to be of clinical importance.     

How does fluoride affect dentin microhardness and mineralization?

Fluoride (F) has been a useful instrument in caries prevention. However, only limited data exist on the effect of its long-term use on dentin mineralization patterns and microhardness. The objective of this study was to evaluate the influence of tooth F concentration ([F]) and dental fluorosis (DF) severity on dentin microhardness and mineralization. We collected 137 teeth in Montreal and Toronto, Canada, and Fortaleza, Brazil, where optimum or suboptimum levels of water F were 0.2 ppm, 1 ppm, and 0.7 ppm, respectively. Teeth were analyzed for DF severity, dentin [F], enamel [F], dentin microhardness, and dentin mineralization. Dentin [F] correlated with DF severity; enamel [F] correlated with dentin microhardness and dentin mineralization; DF severity correlated with dentin microhardness. Genetic factors (e.g., DF severity) and environmental factors (e.g., tooth [F]) influenced the mechanical properties (microhardness) of the teeth, while only the environmental factors influenced their material properties (e.g., mineralization). Fortaleza teeth were harder and less mineralized and presented higher dentin [F] values. Montreal teeth presented lower levels of DF when compared with both Toronto and Fortaleza teeth.     

A 31-year-old woman with jaw deviation and pain: Part I

J Evid Base Dent Pract 2002;2:168-74     

Cognitive and learning styles as predictors of success on the National Board Dental Examination

Using a deidentified retrospective dataset of three cohorts of matriculated dental students, we measured the degree to which selected student attributes, the Learning Type Measure, the Myers-Briggs Type Indicator, and Dental Admission Test subtests scores predicted passage on the National Board Dental Examination (NBDE), Parts I and II. Gender, Myers-Briggs Type Indicators, and the Dental Admission Test subtests for academic average and biology were found to be predictive of passing the NBDE Part I. Gender, a Myers-Briggs Type Indicator (thinking over feeling), and the Dental Admission Test subtests on reading and biology were found to be predictive of passing the NBDE Part II. The Learning Type Measure was not found to be predictive of passing the NBDE Part I or Part II. This study holds implications for heightening faculty members' awareness of students' aptitude and cognitive attributes, for teaching, and for the admissions process.     

pH regulation of urease levels in Streptococcus salivarius

Potential mechanisms for regulation of urease levels in Streptococcus salivarius were examined, including: induction by urea, nitrogen or carbon source repression, and effects of pH and CO2 (because CO2 enrichment enhanced urease detection on urea agar plates). Regulation by either pH or CO2 was confirmed by comparison of the urease accumulation pattern during anaerobic growth under CO2 with that under N2. Under CO2, there was an initial buffering plateau at pH 6.2 and a rate of Streptococcus salivarius urease accumulation three-fold that under N2, with a pH 7.6 plateau. With both gas phases there was also an increase in the rate of urease appearance coincident with the decrease in medium pH following the pH plateau. The effects of pH, CO2, and HCO3- on urease levels and on growth were separately assessed by culture in media containing 0, 25, 100 mmol/L KHCO3 buffered at different pH levels. There was an inverse relationship between the logarithm of the urease level after 24-hour growth and the pH during growth-the urease specific activity was 100-fold higher at pH 5.5, compared with pH 7.0 and above. HCO3-/CO2 (100 mmol/L) had little effect on urease levels, but was essential for growth at pH 5.5. There was no significant urease induction by urea, or repression by ammonia or glucose. There was also evidence of pH regulation of urease levels in some staphylococci, Klebsiella pneumonia, and Corynebacterium renale, but not in Actinomyces naeslundii and several other species. We conclude that the external pH is a major factor regulating urease levels in S. salivarius and possibly some other species-a mechanism equivalent to urease repression by OH-.     

The optimal management of variant histology in muscle invasive bladder cancer

Bladder cancer is a heterogenous disease that is associated with tangible mortality in muscle invasive disease. The WHO 2016 classification of urothelial tumours reflects the contemporary approach towards histological variants in bladder cancer, including variants of urothelial carcinoma (UC) and non-urothelial variants. This review focuses on variant histology in UC, and discusses the importance of accurate histological diagnosis, and subsequent risk stratification and therapeutic decision making based on proper variant recognition. Most urothelial variants are associated with poorer outcomes compared to conventional UC, although some perform reasonably better. However, high quality evidence detailing optimal treatment and survival outcomes are still lacking in literature, due to the rarity of these cases.