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Abstract Osteoporosis is a global public health problem, with fractures contributing to significant morbidity and mortality. Although postmenopausal osteoporosis is most common, up to 30% of postmenopausal women, > 50% of premenopausal women, and between 50% and 80% of men have secondary osteoporosis. Exclusion of secondary causes is important, as treatment of such patients often commences by treating the underlying condition. These are varied but often neglected, ranging from endocrine to chronic inflammatory and genetic conditions. General screening is recommended for all patients with osteoporosis, with advanced investigations reserved for premenopausal women and men aged < 50 years, for older patients in whom classical risk factors for osteoporosis are absent, and for all patients with the lowest bone mass (Z-score ≤ −2). The response of secondary osteoporosis to conventional anti-osteoporosis therapy may be inadequate if the underlying condition is unrecognized and untreated. Bone densitometry, using dual-energy x-ray absorptiometry, may underestimate fracture risk in some chronic diseases, including glucocorticoid-induced osteoporosis, type 2 diabetes, and obesity, and may overestimate fracture risk in others (eg, Turner syndrome). FRAX and trabecular bone score may provide additional information regarding fracture risk in secondary osteoporosis, but their use is limited to adults aged ≥ 40 years and ≥ 50 years, respectively. In addition, FRAX requires adjustment in some chronic conditions, such as glucocorticoid use, type 2 diabetes, and HIV. In most conditions, evidence for antiresorptive or anabolic therapy is limited to increases in bone mass. Current osteoporosis management guidelines also neglect secondary osteoporosis and these existing evidence gaps are discussed. Graphical Abstract Graphical Abstract

Disentangling tree growth requires more than ring width data only. Densitometry is considered a valuable proxy, yet laborious wood sample preparation and lack of dedicated software limit the widespread use of density profiling for tree ring analysis. An X-ray computed tomography-based toolchain of tree increment cores is presented, which results in profile data sets suitable for visual exploration as well as density-based pattern matching. Two temperate (Quercus petraea, Fagus sylvatica) and one tropical species (Terminalia superba) were used for density profiling using an X-ray computed tomography facility with custom-made sample holders and dedicated processing software. Density-based pattern matching is developed and able to detect anomalies in ring series that can be corrected via interactive software. A digital workflow allows generation of structure-corrected profiles of large sets of cores in a short time span that provide sufficient intra-annual density information for tree ring analysis. Furthermore, visual exploration of such data sets is of high value. The dated profiles can be used for high-resolution chronologies and also offer opportunities for fast screening of lesser studied tropical tree species.

Purpose This study aims to analyze corneal densitometry (CD) values in individuals diagnosed with Type 2 Diabetes Mellitus (DM) using the Pentacam Scheimpflug imaging system and to compare the obtained data with those from a control group consisting of healthy individuals. Methods The study included 74 eyes of 37 patients diagnosed with Type 2 Diabetes Mellitus (DM) and 54 eyes of 27 healthy volunteers matched for age and gender. All participants underwent measurements of flat keratometry (K1), steep keratometry (K2), maximum keratometry (Kmax), central corneal thickness (CCT), thinnest corneal thickness (TCT), average anterior and posterior elevation at the corneal apex (AAE and APE), corneal volume (CV) and CD. All measurements were performed using the Pentacam HR device (Oculus, Germany), which operates based on the Scheimpflug imaging principle. CD was evaluated in detail according to radial zones (0–2 mm, 2–6 mm, 6–10 mm, 10–12 mm) and corneal depths (anterior, central, posterior, and total). Only newly diagnosed Type 2 DM patients were included in the study, while those with diabetic retinopathy or maculopathy were excluded. HbA1c levels of all patients were recorded. Statistical analysis of the data was conducted using SPSS software version 22.0, and a p-value of < 0.05 was considered statistically significant. Results The mean age of the Type 2 Diabetes Mellitus (DM) group was 50.51 ± 8.93 years, while the mean age of the healthy control group was 50.89 ± 5.71 years. There were no statistically significant differences between the two groups in terms of age and gender distribution ( p  = 0.42 and p  = 0.20, respectively). Similarly, no significant differences were observed between the groups in terms of K1, K2, Kmax, CCT, TCT, AAE,APE and CV ( p  = 0.51; p  = 0.50; p  = 0.48; p  = 0.95; p  = 0.99; p  = 0.50; p  = 0.29; p  = 0,58 respectively). In contrast, CD values were significantly higher in the Type 2 DM group compared to the healthy control group across all zones (0–2 mm, 2–6 mm, 6–10 mm, 10–12 mm) and at all corneal depths (anterior, central, posterior, total) ( p  < 0.01). A low-level positive correlation was found between HbA1c levels and AAE (r = 0.281; p  = 0.015). In addition, a very weak negative correlation was observed between HbA1c levels and CD values in the anterior 2–6 mm zone (r = –0.240; p  = 0.035). Conclusion In this study, CD values were found to be significantly higher in patients with Type 2 DM compared to healthy individuals. This finding suggests that chronic hyperglycemia may lead to both morphological and functional changes in the corneal tissue.

Purpose This study aimed to evaluate correlations between corneal optical densitometry (COD) and corneal higher-order aberrations (HOAs). Design A prospective cross-sectional study. Methods A total of 67 participants were enrolled. The Pentacam quantified total COD and corneal HOAs. Coma and trefoil were described using the root mean square (RMS). HOAs measurements, including total HOA, spherical aberration (Z40), vertical coma (Z3-1), horizontal coma (Z31), oblique trefoil (Z3-3), horizontal trefoil (Z33), coma RMS (Z3 ± 1 RMS), and trefoil RMS (Z3 ± 3 RMS) of the total, anterior, and posterior corneas, were calculated for both the central 4.0 mm diameter and the central 6.0 mm diameter zones. Results In the central 4.0 mm diameter zone, total COD exhibited significant positive correlations with HOA, Z40, and Z3 ± 1 RMS of the total cornea, HOA and Z40 of the anterior cornea, as well as Z40 and Z31 of the posterior cornea; in the 6.0 mm zone, total COD was positively correlated with HOA, Z40, and Z3 ± 1 RMS of the total cornea, HOA of the anterior cornea, as well as Z40, Z3-1, Z31, and Z3 ± 1 RMS of the posterior cornea ( P  < 0.05 for each one). Age and COD showed a statistically positive correlation (r s = 0.350, P  = 0.004). Conclusions An increase in COD may result in elevated levels of corneal HOAs, particularly including total HOA, spherical aberration, and coma. This increase could potentially compromise the sphericity, symmetry, and regularity of the cornea due to age-related changes in corneal microstructure and composition, even in clinically transparent corneas.

Background and Objectives: The aim of this study is to evaluate and compare changes in corneal densitometry after standard (30 min exposure time of 3 mW/cm2 UVA) and accelerated (10 min exposure time of 9 mW/cm2 UVA) protocols of corneal cross-linking (CXL) in patients with progressive keratoconus. Materials and Methods: This study included a total of 38 eyes of 38 patients divided into two equal-sized subgroups. CXL was performed in one group according to the standard epithelium-off protocol (30 min, 3 mW/cm2 UVA) and in the other group according to an accelerated epithelium-off protocol (10 min, 9 mW/cm2 UVA). Scheimpflug imaging was used to evaluate corneal densitometry in the anterior, central, and posterior corneal layers in three concentric zones (0–2 mm, 2–6 mm, and 6–10 mm) at baseline and 1, 3, and 9 months after surgery. Results: This study included 38 patients divided into two subgroups of 19. One group of patients underwent standard and the other accelerated CXL protocol. Participants in the accelerated group were significantly older (p < 0.001). 9 months after CXL treatment, the accelerated group showed higher central and posterior corneal densitometry values, but, after adjusting for age and baseline values, ANCOVA analysis revealed no significant intergroup differences. Both protocols led to overall reductions in corneal densitometry over time. Conclusions: Both the standard and accelerated CXL protocols induce transient corneal haze, which can be objectified by increased corneal densitometry values in first three months post-CXL. The dynamics of the onset and recovery of postoperative corneal haze are comparable and similar in both protocols.

Purpose To determine normative corneal densitometry values in relation to age, sex, refractive error, corneal thickness, and keratometry, measured using the Oculus Pentacam system. Methods Three hundred and thirty-eight healthy subjects (185 men; 153 women) with no corneal disease underwent an exhaustive ocular examination. Corneal densitometry was expressed in standardized grayscale units (GSU). Results The mean corneal densitometry over the total area was 16.46 ± 1.85 GSU. The Pearson correlation coefficient for total densitometry was r  = 0.542 ( p  < 0.001). Statistically significant differences were found between men and women for the total area ( p  = 0.006), with readings of 16.22 ± 1.54 GSU and 16.60 ± 1.83 GSU, respectively. When the cornea was divided into layers of different depths, a significant correlation was found for all layers and age: r  = 0.447 ( p  < 0.001), r  = 0.563 ( p  < 0.001), and r  = 0.520 ( p  < 0.001) for the anterior, central, and posterior layers, respectively. However, when the cornea was divided into concentric annuli starting from the center of the cornea, densitometry was strongly correlated only with age in the 6–10-mm annulus ( p  < 0.001). Neither mean keratometry nor spherical equivalent was correlated with corneal densitometry in any zone of the cornea ( p  > 0.05). Conclusions This is the first report of normative corneal densitometry values in relation to keratometry, corneal thickness, and spherical equivalent measured with the latest Oculus Pentacam software. Corneal densitometry increases with age, but corneal keratometry and refractive parameters do not affect light scattering in the human cornea.

Metronidazole is a drug widely used in the prevention and treatment of bacterial infections. Due to its possibility of the formation of stable metal complexes, it was decided to broaden its activity spectrum by introducing the silver(I) coordination compounds i.e., [Ag(MTZ)2NO3] and [(Ag(MTZ)2)2]SO4, which have significant antibacterial properties. The paper presents a description of a new qualitative and quantitative analysis of metronidazole in bulk and possible pharmaceutical preparations by thin-layer chromatography with densitometric detection. Optimal separation conditions were selected, and the analytical procedure was validated according to the ICH guidelines. The obtained data indicate that the method is sufficiently sensitive, precise, and accurate. The stability of the metronidazole solutions obtained from tablets, pure metronidazole, and its silver(I) complexes was tested. The research was carried out in various environments, at different temperatures, in H2O2 solution, and during exposure to radiation (UV, sunlight). The greatest degradation was found in the alkaline environment and at higher temperatures. The silver(I) complexes exhibited relatively high stability under analyzed conditions that are higher than standard metronidazole solutions and tablets. The observations were confirmed by the kinetic and thermodynamic analysis. The described studies of new metronidazole silver(I) complexes increase the potential for their application in infections both in humans and animals.

Purpose This study aimed to investigate corneal densitometry (CD), visual, and refractive outcomes after transepithelial photorefractive keratectomy (TPRK) using smart pulse technology (SPT), known as the SmartSurface procedure, in patients treated with or without mitomycin C (MMC) at concentrations of 0.01% and 0.02%. Methods This retrospective study analyzed 138 eyes of 138 patients who underwent SmartSurface surgery and were categorized into three groups based on intraoperative MMC concentration: the MMC 0.02 group (0.02% MMC), the MMC 0.01 group (0.01% MMC), and the Control group (no MMC), with 46 eyes per group. Corneal haze, uncorrected distance visual acuity (UDVA), and spherical equivalent (SE) were assessed preoperatively and at 2 weeks, 1 month, and 3 months postoperatively. Corneal densitometry was performed across different concentric radial zones (0–2, 2–6, and 6–10 mm annulus) and layers (anterior, central, posterior, and total) using Scheimpflug imaging preoperatively and at the same postoperative time points. Results Three months after SmartSurface treatment, the incidence of haze was significantly lower in the MMC 0.01 (6.52%) and MMC 0.02 (4.35%) groups than in the Control group (15.22%) ( P  = 0.048 and P  = 0.01, respectively). The MMC 0.01 and MMC 0.02 groups showed no significant differences in haze incidence ( P  = 0.244). Furthermore, no significant differences were observed in UDVA or SE among the three groups at any postoperative time point (all P  > 0.05). In terms of corneal densitometry, three months after surgery, the central layer CD values in the 0–2 mm zone (MMC 0.01 : 14.48 ± 1.21 GSU vs. MMC 0.02 : 14.56 ± 1.01 GSU vs. Control: 15.23 ± 1.25 GSU) and the posterior layer CD values (MMC 0.01 : 11.49 ± 0.70 GSU vs. MMC 0.02 : 11.40 ± 0.70 GSU vs. Control: 11.96 ± 0.78 GSU) were significantly lower in both MMC groups compared to the Control group (all P  < 0.05). Similarly, in the 2–6 mm zone, the posterior layer CD values (MMC 0.01 : 10.41 ± 0.75 GSU vs. MMC 0.02 : 10.38 ± 0.59 GSU vs. Control: 10.88 ± 0.71 GSU) and total layer CD values (MMC 0.01 : 13.39 ± 0.54 GSU vs. MMC 0.02 : 13.36 ± 0.49 GSU vs. Control: 13.65 ± 0.51 GSU) were significantly lower in both MMC groups than in the Control group (all P  < 0.05). However, no significant differences in CD values were found between the MMC 0.01 and MMC 0.02 groups across any zone or layer (all P  > 0.05). Conclusion Both 0.01% and 0.02% MMC are similarly effective in preventing haze and enhancing corneal clarity following SmartSurface surgery. However, given the unproven long-term safety of MMC, its use at a lower concentration is advisable to avert potential complications.

This study aimed to evaluate the correlation between the Osteoporosis Self-Assessment Tool for Asians (OSTA) and three panoramic indices in relation to z-score and t-score values using quantitative ultrasound (QUS) bone densitometry. The sensitivity, specificity, and area under the curve (AUC) of the OSTA index were also measured using the QUS tool to evaluate the method's performance in identifying people at risk of osteoporosis. The study employed a cross-sectional design with 387 participants (190 men, 197 women). Patients' mandibular cortical indexes (MCI), mandibular cortical widths (MCW), and panoramic mandibular indexes (PMI) were measured from panoramic images. The sensitivity, specificity, and AUC were calculated using an OSTA index cutoff of ≤−1 and a t-score of ≤−1.0 for the QUS bone densitometry. The coefficient correlation of the OSTA index with the z-score (r = −0.563, p < 0.001) and t-score (r = −0.740, p < 0.001) shows a higher value than the MCI, MCW, and PMI, per the QUS. The sensitivity, specificity, and AUC values with a cutoff t-score of ≤−1.0 per the QUS in men was 90%, 50%, and 0.812, and in women, 96.8%, 30%, and 0.862. The OSTA index is a simple method that can be used in general dental practice.

Individuals with osteoporosis are predisposed to hip fracture during trips, stumbles or falls, but half of all hip fractures occur in those without generalised osteoporosis. By analysing ordinary clinical CT scans using a novel cortical thickness mapping technique, we discovered patches of markedly thinner bone at fracture-prone regions in the femurs of women with acute hip fracture compared with controls. We analysed CT scans from 75 female volunteers with acute fracture and 75 age- and sex-matched controls. We classified the fracture location as femoral neck or trochanteric before creating bone thickness maps of the outer 'cortical' shell of the intact contra-lateral hip. After registration of each bone to an average femur shape and statistical parametric mapping, we were able to visualise and quantify statistically significant foci of thinner cortical bone associated with each fracture type, assuming good symmetry of bone structure between the intact and fractured hip. The technique allowed us to pinpoint systematic differences and display the results on a 3D average femur shape model. The cortex was generally thinner in femoral neck fracture cases than controls. More striking were several discrete patches of statistically significant thinner bone of up to 30%, which coincided with common sites of fracture initiation (femoral neck or trochanteric). Femoral neck fracture patients had a thumbnail-sized patch of focal osteoporosis at the upper head-neck junction. This region coincided with a weak part of the femur, prone to both spontaneous 'tensile' fractures of the femoral neck, and as a site of crack initiation when falling sideways. Current hip fracture prevention strategies are based on case finding: they involve clinical risk factor estimation to determine the need for single-plane bone density measurement within a standard region of interest (ROI) of the femoral neck. The precise sites of focal osteoporosis that we have identified are overlooked by current 2D bone densitometry methods.