Κυριακή 19 Φεβρουαρίου 2023

Biomechanical influence of narrow‐diameter implants placed at the crestal and subcrestal level in the maxillary anterior region. A 3D finite element analysis

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Abstract

Purpose

To evaluate the tendency of movement, stress distribution, and microstrain of single-unit crowns in simulated cortical and trabecular bone, implants, and prosthetic components of narrow-diameter implants with different lengths placed at the crestal and subcrestal levels in the maxillary anterior region using 3D finite element analysis.

Materials and Methods

Six 3D models were simulated using Invesalius 3.0, Rhinoceros 4.0, and SolidWorks software. Each model simulated the right anterior maxillary region including a Morse taper implant of Ø 2.9 mm with different lengths (7 mm, 10 mm, and 13 mm) placed at the crestal and subcrestal level and supporting a cement-retained monolithic single crown in the area of tooth #12. The finite element analysis was performed using ANSYS 19.2. The simulated applied force was 178 N at 0°, 30°, and 60°. The results were analyzed using maps of displacement, von Mises stress (vM), maximum principal stress, and microstrain.

Results

Models with implants at the subcrestal level showed greater displacement. von Mises stress increased in the implant and prosthetic components when implants were placed at the subcrestal level compared with the crestal level; the length of the implants had a low influence on the stress distribution. Higher stress and strain concentrations were observed in the cortical bone of the subcrestal placement, independent of implant length. Non-axial loading influenced the increased stress and strain in all the evaluated structures.

Conclusions

Narrow-diameter implants positioned at the crestal level showed a more favorable biomechanical behavior for simulated cortical bone, implants, and prosthetic components. Implant length had a smaller influence on stress or strain distribution than the other variables.

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Implementable Deep Learning for Multi‐sequence Proton MRI Lung Segmentation: A Multi‐center, Multi‐vendor, and Multi‐disease Study

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Background

Recently, deep learning via convolutional neural networks (CNNs) has largely superseded conventional methods for proton (1H)-MRI lung segmentation. However, previous deep learning studies have utilized single-center data and limited acquisition parameters.

Purpose

Develop a generalizable CNN for lung segmentation in 1H-MRI, robust to pathology, acquisition protocol, vendor, and center.

Study type

Retrospective.

Population

A total of 809 1H-MRI scans from 258 participants with various pulmonary pathologies (median age (range): 57 (6–85); 42% females) and 31 healthy participants (median age (range): 34 (23–76); 34% females) that were split into training (593 scans (74%); 157 participants (55%)), testing (50 scans (6%); 50 participants (17%)) and external validation (164 scans (20%); 82 participants (28%)) sets.

Field Strength/Sequence

1.5-T and 3-T/3D spoiled-gradient recalled and ultrashort echo-time 1H-MRI.

Assessment

2D and 3D CNNs, trained on single-center, multi-sequence data, and the conventional spatial fuzzy c-means (SFCM) method were compared to manually delineated expert segmentations. Each method was validated on external data originating from several centers. Dice similarity coefficient (DSC), average boundary Hausdorff distance (Average HD), and relative error (XOR) metrics to assess segmentation performance.

Statistical Tests

Kruskal–Wallis tests assessed significances of differences between acquisitions in the testing set. Friedman tests with post hoc multiple comparisons assessed differences between the 2D CNN, 3D CNN, and SFCM. Bland–Altman analyses assessed agreement with manually derived lung volumes. A P value of <0.05 was considered statistically significant.

Results

The 3D CNN significantly outperformed its 2D analog and SFCM, yielding a median (range) DSC of 0.961 (0.880–0.987), Average HD of 1.63 mm (0.65–5.45) and XOR of 0.079 (0.025–0.240) on the testing set and a DSC of 0.973 (0.866–0.987), Average HD of 1.11 mm (0.47–8.13) and XOR of 0.054 (0.026–0.255) on external validation data.

Data Conclusion

The 3D CNN generated accurate 1H-MRI lung segmentations on a heterogenous dataset, demonstrating robustness to disease pathology, sequence, vendor, and center.

Evidence Level

4.

Technical Efficacy

Stage 1.
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Equity in adjuvant radiotherapy utilization in locally advanced head and neck cancer: A SEER‐data based study

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Abstract

Background

Not all patients with locally advanced head and neck cancer (HNC) who are eligible for adjuvant radiotherapy (RT) following upfront surgery appear to receive it.

Methods

Data were obtained from the Surveillance, Epidemiology, and End Results (SEER) database. Selected patients from 2009 to 2018 had locally advanced HNC, underwent upfront surgery, and were eligible for adjuvant RT. Multivariable logistic regression and chi-squared test were used to analyze available patient and tumor characteristics.

Results

Of 12 549 patients, 84.5% underwent adjuvant RT, 15.5% did not. Characteristics associated with lowest adjuvant RT utilization included cancers of the larynx (p < 0.0001) and gingivae (p < 0.0001), age 80 and above (p < 0.0001), unpartnered status (p < 0.0001), and residence within a nonmetropolitan area (p < 0.0024).

Conclusions

Tumor subsite, age, partnered status, and rural/urban residence correlate with omission of adjuvant RT in locally advanced HNC.
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An evaluation of mechanical and biophysical skin parameters at different body locations

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Abstract

Background

Skin is the largest organ in the body, representing an important interface to monitor health and disease. However, there is significant variation in skin properties for different ages, genders and body regions due to the differences in the structure and morphology of the skin tissues. This study aimed to evaluate the use of non-invasive tools to discriminate a range of mechanical and functional skin parameters from different skin sites.

Materials and methods

A cohort of 15 healthy volunteers was recruited following appropriate informed consent. Four well-established CE-marked non-invasive techniques were used to measure four anatomical regions: palm, forearm, sole and lower lumbar L3, using a repeated measures design. Skin parameters included trans-epidermal water loss (TEWL), pH (acidity), erythema, stratum corneum hydration and stiffness and elasticity using Myoton Pro (skin and muscle probe). Differences between body locations for each parameter and the intra-rater reliability between days were evaluated by the same operator.

Results

The results indicate that parameters differed significantly between skin sites. For the Myoton skin probe, the sole recorded the highest stiffness value of 1006 N/m (SD ± 179), while the lower lumbar recorded the least value of 484 N/m (SD ± 160). The muscle indenter Myoton probe revealed the palm's highest value of 754 N/m (± 108), and the lower lumbar recorded the least value of 208 N/m (SD ± 44). TEWL values were lowest on the forearm, averaging 11 g/m2/h, and highest on the palm, averaging 41 g/m2/h. Similar skin hydration levels were recorded in three of the four sites, with the main difference being observed in the sole averaging 13 arbitrary units. Erythema values were characterised by a high degree of inter-subject variation, and no significant differences between sites or sides were observed. The Myoton Pro Skin showed excellent reliability (intra-class correlation coefficients > 0.70) for all sites with except ion of one site right lower back; the Myoton pro muscle probes showed good to poor reliability (0.90–017), the corneometer showed excellent reliability (>0.75) among all the sites tested, and the TEWL showed Good to poor reliability (0.74–0.4) among sites.

Conclusion

The study revealed that using non-invasive methods, the biophysical properties of skin can be mapped, and significant differences in the mechanical and functional properties of skin were observed. These parameters were reliably recorded between days, providing a basis for their use in assessing and monitoring changes in the skin during health and disease.
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Multifunctional Two-Dimensional Bi2Se3 Nanodiscs for Anti-Inflammatory Therapy of Inflammatory Bowel Diseases

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Publication date: Available online 17 February 2023

Source: Acta Biomaterialia

Author(s): Cong Zhang, Qingrong Li, Jie Shan, Jianghao Xing, Xiaoyan Liu, Yan Ma, Haisheng Qian, Xulin Chen, Xianwen Wang, Lian-Ming Wu, Yue Yu
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An integrated strategy to identify COVID‐19 causal genes and characteristics represented by LRRC37A2

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ABSTRACT

Genome-wide association study (GWAS) could identify host genetic factors associated with coronavirus disease 2019 (COVID-19). The genes or functional DNA elements through which genetic factors affect COVID-19 remain uncharted. The expression quantitative trait locus (eQTL) provides a path to assess the correlation between genetic variations and gene expression. Here, we firstly annotated GWAS data to describe genetic effects, obtaining genome-wide mapped genes. Subsequently, the genetic mechanisms and characteristics of COVID-19 were investigated by an integrated strategy that included three GWAS-eQTL analysis approaches. It was found that 20 genes were significantly associated with immunity and neurological disorders, including prior and novel genes such as OAS3 and LRRC37A2. The findings were then replicated in single-cell datasets to explore the cell-specific expression of causal genes. Furthermore, associations between COVID-19 and neurological disorders were assessed as a cau sal relationship. Finally, the effects of causal protein-coding genes of COVID-19 were discussed using cell experiments. The results revealed some novel COVID-19-related genes to emphasize disease characteristics, offering a broader insight into the genetic architecture underlying the pathophysiology of COVID-19.

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The prevalence and influencing factors of gag reflex in children aged 7‐14 years in the dental setting

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Abstract

Background

Gag reflex may occur in patients of all ages and often considered having a multifactorial etiology.

Objective

The aim of the study was to evaluate the prevalence and influencing factors of gag reflex in Turkish children aged 7-14 years in the dental setting.

Methods

This cross-sectional study was carried out among 320 children aged between 7-14 years. First, an anamnesis form which include sosyodemographic status, monthly level of income, children past medical, and dental experiences was filled by mothers. Children's fear levels were evaluated using the Dental Subscale of Children's Fear Survey Schedule(CFSS-DS) while mother's anxiety levels using the Modified Dental Anxiety Scale(MDAS). The revised dentist section of gagging problem assessment questionnaire (GPA-R-de) were used for both children and mothers. Statistical analysis were done with SPSS program.

Results

The prevalence of gag reflex among children was 34.1%, among mothers was 20.3%. The association between child and mother gagging was found statistically significant (χ2=53.121, p<0.001). When the mother of the child gagged, the risk of child gagging increases 6.83 times (p<0.001). Higher CFSS-DS scores of children increase risk of gagging (OR=1.052, p=0.023). Children who were previously treated mostly in public hospitals significantly more likely to gag compared with private dental clinics (OR=10.990, p<0.001).

Conclusion

It was concluded that negative past dental experiences, previous dental treatments with local anesthesia, history of hospital admission, number and place of previous dental visits, dental fear level of children, and low education level and gagging of mother have an influence on the gagging of children.
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The ability of magnetic resonance imaging to predict lymph node metastases and the risk of recurrence in rectal cancer

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Abstract

Aim

This study aimed to examine the diagnostic accuracy and prognostic value of magnetic resonance imaging (MRI) detected lymph nodes in rectal cancer.

Method

We evaluated 806 rectal cancer patients consecutively operated on between 2015 and 2018 at Helsinki University Hospital. In total, 485 patients met the inclusion criteria of presenting with stage I–III disease and were intended for curative treatment at the time of diagnosis. The effect of MRI-detected clinical lymph node status (cN) on cumulative overall survival (OS), disease-specific survival (DSS) and disease-free survival (DFS) was calculated using the Kaplan–Meier analysis.

Results

Negative predictive value (NPV) of MRI-lymphnode negativity was 74.8%. Positive predictive value of lymph node metastasis was only 48.6%. In the Kaplan–Meier survival analysis, OS (p = 0.989), DSS (p = 0.911), and DFS (p = 0.109) did not significantly differ according to MRI nodal status. However, cumulative disease-free survival significantly (p < 0.001) differed according to the histopathological lymph node metastasis status (pN).

Conclusions

MRI detected lymph node positivity appears insufficiently precise and cannot predict disease recurrence or survival. Therefore, it should not serve as an independent risk factor when considering neoadjuvant treatment options for rectal cancer patients.
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Primary tumor resection improves survival of gastrointestinal neuroendocrine carcinoma patients with nonresected liver metastases

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Abstract

Background

The role of primary tumor resection (PTR) in the survival of gastrointestinal neuroendocrine carcinoma (GI-NEC) patients with liver metastases only remains poorly defined. Therefore, we investigated the impact of PTR on the survival of GI-NEC patients with nonresected liver metastases.

Methods

GI-NEC patients with a liver-confined metastatic disease diagnosed between 2016 and 2018 were identified in the National Cancer Database. Multiple imputations by chained equations were used to account for missing data, and the inverse probability of treatment weighting (IPTW) method was used to eliminate selection bias. Overall survival (OS) was compared by adjusted Kaplan–Meier curves and log-rank test with IPTW.

Results

A total of 767 GI-NEC patients with nonresected liver metastases were identified. Among all patients, 177 (23.1%) received PTR and had a significantly favorable OS before (median: 43.6 months [interquartile range, IQR, 10.3–64.4] vs. 8.8 months [IQR, 2.1–23.1], p < 0.001 in log-rank test) and after (median: 25.7 months [IQR, 10.0–64.4] vs. 9.3 months [IQR, 2.2–26.4], p < 0.001 in IPTW-adjusted log-rank test) the IPTW adjustment. Additionally, this survival advantage persisted in an adjusted Cox model (IPTW adjusted hazard ratio = 0.431, 95% confidence interval: 0.332–0.560; p < 0.001). The improved survival persisted in subgroups stratified by primary tumor site, tumor grade, and N stage, even in the complete cohort (excluding patients with missing data).

Conclusions

PTR led to improved survival for GI-NEC patients with nonresected liver metastases regardless of primary tumor site, tumor grade, and N stage. However, the decision for PTR should be made on an individualized basis following multidisciplinary evaluation.
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Risk and incidence of breast cancer in transgender individuals: a systematic review and meta-analysis

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imageBackground and aims The risk of developing breast cancer in transgender individuals [male-to-female (MtF) or female-to-male (FtM)] is still inadequately quantified. We aimed to evaluate the impact of breast cancer in this population. Methods We conducted a systematic literature search and review using the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines through the PUBMED and SCOPUS databases. We identified six cohort studies (for both populations) plus 35 case reports. Incidence and breast cancer risk quantification were the main outcomes considered. Results FtM individuals had a higher risk of developing breast cancer in comparison to cisgender men [standardized incidence ratio (SIR) = 63.4; 95% confidence interval (CI), 32.2–124.9] but a lower risk than cisgender women (SIR = 0.42; 95% CI, 0.07–2.41). Similarly, MtF individuals were at higher risk of developing breast cancer in comparison to cisgender men (SIR = 22.5; 95% CI, 5.54–91.8) and at lower risk than cisgender women (SIR = 0.30; 95% CI, 0.22–0.42). Conclusion In this systematic study and meta-analysis, we identified that FtM and MtF individuals are at substantially higher risk of developing breast cancer in comparison to cisgender men, though at lower risk than cisgender women. These individuals, in the absence of defined guidelines for breast cancer prevention, should periodically undergo breast or chest examinations.
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