Evaluation of the Posterior Tilt Angle in Predicting Failure of Nondisplaced Femoral Neck Fractures After Internal Fixation: A Systematic Review.

OBJECTIVE: To evaluate the posterior tilt angle (PTA) in predicting treatment failure after internal fixation of nondisplaced femoral neck fractures as graded by the Garden classification, which is based solely on anterior-posterior radiographic evaluation. DATA SOURCES: A search was conducted of all published literature in the following databases from inception to December 20, 2021: PubMed, Embase, Cochrane Library, Web of Science, Scopus, and ClinicalTrials.gov . STUDY SELECTION: We included English-language randomized controlled trials, prospective and retrospective cohort studies that reported malunion/nonunion, avascular necrosis, fixation failure, or reoperations in patients with nondisplaced femoral neck fractures treated with internal fixation who were evaluated for PTA using either lateral radiograph or computed tomography. DATA EXTRACTION: All abstract, screening, and quality appraisal was conducted independently by 2 authors. Data from included studies were extracted manually and summarized. The Methodological Index for Non-Randomized Studies criteria was used for quality appraisal. DATA SYNTHESIS: Odds ratios with 95% confidence intervals were calculated for treatment failure, defined as nonunion/malunion, avascular necrosis, fixation failure, or reoperation, in cases involving preoperative PTA ≥20-degrees and <20-degrees. Statistical significance was set at P < 0.05. RESULTS: Nondisplaced femoral neck fractures with PTA >20-degrees had a 24% rate of treatment failure compared with 12% for those <20-degrees [odds ratios, 3.21 (95% confidence intervals, 1.95-5.28); P < 0.001]. CONCLUSION: PTA is a predictor of treatment failure in nondisplaced femoral neck fractures treated with internal fixation. Nondisplaced femoral neck fractures with a PTA >20-degrees may warrant alternative treatment modalities. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Determination of the ground- and excited-state dipole moments of bromocresol purple in protic and aprotic solvents.

Although it has been widely recognized that hydrogen bonds play a significant role in the photophysics of molecules, this phenomenon has rarely been applied to the solvatochromic method for determination of dipole moments. The difference in the dipole moment between the ground and excited state was determined in protic and aprotic solvents using both the Lippert-Mataga equation and the Bilot-Kawski equation for bromocresol purple, a molecule capable of hydrogen-bond donation and acceptance. The dipole change in protic environments was determined to be 15.2 ± 1.0 D for the Lippert-Mataga method and 9.2 ± 1.0 D for the Bilot-Kawski method, while the change in aprotic environments was 10.4 ± 1.0 D and 6.7 ± 1.0 D, respectively. Both methods highlighted the importance of hydrogen bonding in stabilizing increased charge-separation of the excited state, allowing for larger changes in dipole moments in protic environments. This study further validates a simple, rational modification to the commonly used methods that allows access to dipole-moment data on dyes with hydrogen-bonding capabilities through solvatochromic experiments.

Chemical investigation of the medicinal and ornamental plant Angelonia angustifolia Benth. reveals therapeutic quantities of lupeol.

Angelonia angustifolia Benth. is a small herbaceous plant with documented use as an anti-inflammatory remedy by indigenous cultures in Latin America. It has subsequently been developed as an ornamental annual widely available in nurseries in the United States. Chemical investigation led to the discovery that lupeol is the major organic soluble constituent in the roots, and is present in large quantities in the aerial structures of the plant. Lupeol was identified by 1D and 2D NMR spectroscopic techniques and quantified by HPLC-MS. The concentration of lupeol (9.14 mg/g in roots) in A. angustifolia is approximately 3 times higher than any previously reported sources. Therefore, the amount of lupeol in the roots of a single individual of A. angustifolia greatly exceeds the previously determined topical threshold for significant reduction of inflammation. The presence of topically therapeutic levels of lupeol in A. angustifolia provides chemical rationale for its indigenous use. In addition, the established cultivation of A. angustifolia could allow this plant to be used as a source of the important bioactive molecule lupeol, or to be developed as a nutraceutical without damaging wild populations.