Search Results (590)

Prosthetic heart valves (PHVs) are employed to replace the diseased native valve as a treatment of severe aortic valve disease. This study aimed to evaluate the effect of curvature of the belly curve on valve performance, so as to support a better comprehension of the relationship between valve design and its performance. Five PHV models with different curvatures of the belly curve were established. Iterative implicit fluid–structure interaction simulations were carried out, analyzing in detail the effect of belly curvature on the geometric orifice area (GOA), coaptation area (CA), regurgitant fraction (RF), leaflet kinematics and stress distribution on the leaflets. Overall, GOA and CA were negatively and positively related to the curvature of the belly curve, respectively. Nevertheless, an excessive increase in curvature can lead to incomplete sealing of free edges of the valve during its closure, which resulted in a decrease in CA and an increase in regurgitation. The moderate curvature of the belly curve contributed to reducing RF and fluttering frequency. Valves with small curvature experienced a significantly higher frequency of fluttering. Furthermore, all stress concentrations intensified with the increase in the curvature of the belly curve. The valve with moderate curvature of the belly curve strikes the best compromise between valve performance parameters, leaflet kinematics and mechanical stress. Considering the different effects of the curvature of belly curve on valve performance parameters, the PHV design with variable curvature of belly curve may be a direction towards valve performance optimization. Full article

Background: In systemic sclerosis (SSc), cardiac involvement is frequent, heterogeneous, and related to a poor prognosis. Due to a longer life expectancy, the development of degenerative aortic stenosis (AS) is not uncommon. The aim of this article is to report the characteristics of AS in SSc, analyzing the rate of progression, the management, and the outcome. Methods: This is a case series conducted at the Department of Cardiology of Monaldi Hospital, Naples, Italy. Results: From January 2007 to December 2022, we analyzed 234 patients with SSc. Ten/234 patients (4.3%) showed severe AS and were included in the analysis (age 75.5 years [IQR 58–84], nine females). Nine had limited and one diffuse SSc. Two patients were in NHYA/WHO II and eight in NYHA/WHO III. All had degenerative three-leaflet AS. Two patients showed severe AS at the first evaluation, and eight developed severe AS during the follow-up, with a time progression from moderate to severe AS of 3.2 ± 1.1 years (progression rate −0.190 ± 0.012 cm²/year for aortic valve area, 8.6 ± 6.1 mmHg/year for mean aortic gradient, 16 ± 7 mmHg/year for peak aortic gradient, and 0.5 ± 0.3 m/s/year for aortic peak velocity). Seven out of 10 patients underwent transcatheter aortic valve implantation (TAVI), one underwent surgical aortic valve replacement (SAVR), one was left untreated, and one was on a waiting list for TAVI. No major complications after TAVI or SAVR occurred. At a mean follow-up of 5.9 ± 3.9 years, eight patients are alive and two died. Conclusion: Severe AS is a relevant cardiac complication of SSc and must be considered in the screening and during the follow-up. Its rapid progression rate may tentatively be due to autoimmunity, degenerative burden, and chronic inflammation. Full article

The plasma membrane lipid distribution is asymmetric, with several anionic lipid species located in its inner leaflet. Among these, phosphatidylserine (PS) plays a crucial role in various important physiological functions. Over the last decade several methods have been developed that allow for the fabrication of large or giant unilamellar vesicles (GUVs) with an asymmetric lipid composition. Investigating the physicochemical properties of PS in such asymmetric lipid bilayers and studying its interactions with proteins necessitates the reliable fabrication of asymmetric GUVs (aGUVs) with a high degree of asymmetry that exhibit PS in the outer leaflet so that the interaction with peptides and proteins can be studied. Despite progress, achieving aGUVs with well-defined PS asymmetry remains challenging. Recently, a Ca²⁺-initiated hemifusion method has been introduced, utilizing the fusion of symmetric GUVs (sGUVs) with a supported lipid bilayer (SLB) for the fabrication of aGUVs. We extend this approach to create aGUVs with PS in the outer bilayer leaflet. Comparing the degree of asymmetry between aGUVs obtained via Ca²⁺ or Mg²⁺ initiated hemifusion of a phosphatidylcholine (PC) sGUVwith a PC/PS-supported lipid bilayer, we observe for both bivalent cations a significant number of aGUVs with near-complete asymmetry. The degree of asymmetry distribution is narrower for physiological salt conditions than at lower ionic strengths. While Ca²⁺ clusters PS in the SLB, macroscopic domain formation is absent in the presence of Mg²⁺. However, the clustering of PS upon the addition of Ca²⁺ is apparently too slow to have a negative effect on the quality of the obtained aGUVs. We introduce a data filtering method to select aGUVs that are best suited for further investigation. Full article

It is costly and time-consuming to design and manufacture functional polyurethane heart valve prototypes, to evaluate and comprehend their hemodynamic behaviour. To enhance the rapid and effective design of replacement heart valves, to meet the minimum criteria of FDA and ISO regulations and specifications, and to reduce the length of required clinical testing, computational fluid dynamics (CFD) and finite element analysis (FEA) were used. The results revealed that when the flexibility of the stent was taken into consideration with a uniform leaflet thickness, stress concentration regions that were present close to the commissural attachment were greatly diminished. Furthermore, it was found that the stress on the leaflets was directly impacted by the effect of reducing the post height on both rigid and flexible stents. When varying the leaflet thickness was considered, the high-stress distribution close to the commissures appeared to reduce at thicker leaflet regions. However, thicker leaflets may result in a stiffer valve with a corresponding increase in pressure drop. It was concluded that a leaflet with predefined varying thickness may be a better option. Full article

Transcatheter aortic valve implantation (TAVI) was initially developed for adult patients, but there is a growing interest to expand this procedure to younger individuals with longer life expectancies. However, the gradual degradation of biological valve leaflets in transcatheter heart valves (THV) presents significant challenges for this extension. This study aimed to establish a multiphysics computational framework to analyze structural and flow measurements of TAVI and evaluate the integration of optical fiber and photoplethysmography (PPG) sensors for monitoring valve function. A two-way fluid–solid interaction (FSI) analysis was performed on an idealized aortic vessel before and after the virtual deployment of the SAPIEN 3 Ultra (S3) THV. Subsequently, an analytical analysis was conducted to estimate the PPG signal using computational flow predictions and to analyze the effect of different pressure gradients and distances between PPG sensors. Circumferential strain estimates from the embedded optical fiber in the FSI model were highest in the sinus of Valsalva; however, the optimal fiber positioning was found to be distal to the sino-tubular junction to minimize bending effects. The findings also demonstrated that positioning PPG sensors both upstream and downstream of the bioprosthesis can be used to effectively assess the pressure gradient across the valve. We concluded that computational modeling allows sensor design to quantify vessel wall strain and pressure gradients across valve leaflets, with the ultimate goal of developing low-cost monitoring systems for detecting valve deterioration. Full article

Background: Degenerative aortic valve stenosis (AS) is the most common valvular heart disease among the elderly. Once cardiac symptoms occur, current guidelines recommend aortic valve replacement. Progressive degeneration/calcification reduces leaflet mobility with gradual cardiac output (CO) impairment. Low CO might induce abnormal brain-aging with cognitive impairment and increased risk of dementia, such as Alzheimer’s disease or vascular dementia. On the contrary, cognitive improvement has been reported in patients in whom CO was restored. Transcatheter aortic valve implantation (TAVI) has proven to be a safe alternative to conventional surgery, with a similar mid-term survival and stroke risk even in low-risk patients. TAVI is associated with an immediate CO improvement, also effecting the cerebrovascular system, leading to an increased cerebral blood flow. The correlation between TAVI and cognitive improvement is still debated. The present study aims at evaluating this relationship in a cohort of AS patients where cognitive assessment before and after TAVI was available. Methods: a total of 47 patients were retrospectively selected. A transcranial Doppler ultrasound (TCD) before and after TAVI, a quality of life (QoL) score, as well as a mini-mental state examination (MMSE) at baseline and up to 36 months, were available. Results: TAVI was associated with immediate increase in mean cerebral flow at TCD. MMSE slowly increase at 36-months follow-up with improved QoL mainly for symptoms, emotions and social interactions. Conclusions: this proof-of-concept study indicates that TAVI might induce cognitive improvement in the long-term as a result of multiple factors, such as cerebral flow restoration and a better QoL. Full article

Acomys cahirinus is a unique Rodentia species with several distinctive physiological traits, such as precocial development and remarkable regenerative abilities. These characteristics render A. cahirinus increasingly valuable for regenerative and developmental physiology studies. Despite this, the structure and postnatal development of the central nervous system in A. cahirinus have been inadequately explored, with only sporadic data available. This study is the first in a series of papers addressing these gaps. Our first objective was to characterize the structure of the main visual thalamic region, the lateral geniculate complex, using several neuronal markers (including Ca²⁺-binding proteins, glutamic acid decarboxylase enzyme, and non-phosphorylated domains of heavy-chain neurofilaments) to label populations of principal neurons and interneurons in adult and newborn A. cahirinus. As typically found in other rodents, we identified three subdivisions in the geniculate complex: the dorsal and ventral lateral geniculate nuclei (LGNd and LGNv) and the intergeniculate leaflet (IGL). Additionally, we characterized internal diversity in the LGN nuclei. The “shell” and “core” regions of the LGNd were identified using calretinin in adults and newborns. In adults, the inner and outer parts of the LGNv were identified using calbindin, calretinin, parvalbumin, GAD67, and SMI-32, whereas in newborns, calretinin and SMI-32 were employed for this purpose. Our findings revealed more pronounced developmental changes in LGNd compared to LGNv and IGL, suggesting that LGNd is less mature at birth and more influenced by visual experience. Full article

Background: The mismatch between tricuspid valve (TV) leaflet length and annulus dilation, assessed with the septal–lateral leaflet-to-annulus index (SL-LAI), predicts residual tricuspid regurgitation (TR) following tricuspid transcatheter edge-to-edge-repair (T-TEER). When posterior leaflet grasping is required, the anterior–posterior leaflet-to-annulus index (AP-LAI) may offer additional information. Methods: This single-center retrospective cohort study included all patients referred for T-TEER with severe and symptomatic TR with high surgical risk from April 2021 to March 2024. Patients were categorized into ‘optimal result’ (<moderate TR) or ‘suboptimal result’ (≥moderate TR) groups. The SL-LAI and AP-LAI were calculated using pre-procedural transesophageal echocardiography (TEE) measurements. Results: Of the 25 patients, 12 had suboptimal post-procedural results, while 13 showed optimal outcomes. The optimal result group showed a higher prevalence of type IIIA-IIIB TV morphology (85% vs. 45%, p < 0.05), a wider SL annulus diameter (42.5 ± 5 vs. 37 ± 5 mm, p < 0.05), and a longer posterior leaflet length (28 ± 4 vs. 22 ± 5 mm, p < 0.01). The SL-LAI was lower in the optimal group (1 ± 0.2 vs. 1.2 ± 0.32, p < 0.05), while the AP-LAI was higher (0.7 ± 0.1 vs. 0.5 ± 0.2, p < 0.05). ROC curve analysis showed that the AUC for the AP-LAI was 0.769 (95% CI 0.51–0.93, p < 0.05) and Youden test identified the best cut-off value <0.5 (sensitivity 50% and specificity 100%) for a suboptimal result. The SL-LAI showed a very low AUC in predicting suboptimal results (0.245, 95% CI 0.08–0.47). Comparing the two ROC curves, we showed that AUC difference is significant with the AP-LAI showing the best association with the outcome (p = 0.01). Conclusions: The AP-LAI and SL-LAI can help in predicting post T-TEER results, ameliorating patients’ outcomes and avoiding futile procedures. Full article

Background: Yeo’s index is a novel measure of the severity of rheumatic mitral valve stenosis (MS). It is derived from the product of the mitral leaflet separation index and dimensionless index. This study aims to validate Yeo’s index using a transesophageal echocardiogram (TEE) three-dimensional (3D) mitral valve area (MVA) as a comparator and to compare the concordance of existing echocardiographic measures of the MVA with TEE 3DMVA. Methods and Results: We studied 111 patients with rheumatic MS who underwent both transthoracic echocardiography (TTE) and a TEE assessment of MS severity. Yeo’s index, the MVA determined by 2D planimetry, pressure half-time (PHT) and continuity equation (CE) measured on TTE were compared with the TEE 3DMVA. With a linear correlation, Yeo’s index showed the best correlation with TEE 3DMVA (r² = 0.775), followed by 2D planimetry (r² = 0.687), CE (r² = 0.598) and PHT (r² = 0.363). Using TEE 3DMVA as comparator, Yeo’s index (ρ_c = 0.739) demonstrated the best concordance, followed by 2D planimetry (ρ_c = 0.632), CE (ρ_c = 0.464) and PHT (ρ_c = 0.366). When both Yeo’s index and 2D planimetry suggested significant MS, the positive predictive value was high (an AUC of 0.966 and a PPV of 100.00% for severe MS, and an AUC of 0.864 and a PPV of 85.71% for very severe MS). When both measures suggested the absence of significant MS, the negative predictive value was also high (an AUC of 0.940 and an NPV of 88.90% for severe MS, and an AUC of 0.831 and an NPV of 88.71% for very severe MS). Conclusions: Yeo’s index performed well in identifying severe MS when compared with TEE 3DMVA and may be a useful adjunct to existing methods of measuring MS severity. Combining it with 2D planimetry could further enhance its accuracy. Full article

The aim of this study was to determine the effects of a novel app-based rehabilitation counselling program in patients recovering from total knee arthroplasty. In the app-based rehabilitation counselling program, a counselor provides one-on-one rehabilitation exercises and management-focused psychological counselling after total knee arthroplasty (TKA). This study included 42 patients, who were divided into three groups of 14 patients each: Group A, whose rehabilitation training was based on a guideline leaflet; Group B, whose rehabilitation was based on the app-based rehabilitation counselling program; and Group C, whose rehabilitation training was based on continuous passive motion combined with the app-based rehabilitation counselling program. To determine the effects of rehabilitation, the isokinetic knee muscle strength and knee joint range of motion were measured in addition to knee function tests such as the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the visual analogue scale (VAS) for pain at two and three months after rehabilitation. The comparison of the means of the three groups was analyzed using one-way analysis of variance (ANOVA), with Group C showing significant variance in isokinetic knee muscle strength (p < 0.05), passive ROM (p < 0.01), and WOMAC (p < 0.05) after three months. As a result, this study confirmed the positive potential of the app-based rehabilitation counselling program. Full article

Child abuse affects millions of children globally. Comprehensive training is essential to promote its recognition and trigger appropriate responses to prevent missed opportunities for intervention. We describe a child abuse and child protection training programme for University of Ghana Medical School students and the cross-sectional survey of student assessment at the end. The programme comprised a lectures, dissertations, community surveys, case reports, public health advocacy topics, and poster designs. These were carried out as part of regular coursework in community health, using individual and group—methods. It culminated in a one-day whole-class seminar after their final examinations with completion and analyses of self-administered student assessment questionnaires. The seminar comprised nineteen 10-min oral presentations, twelve poster presentations on community surveys and dissertations, nine educative posters, three leaflets and a question-and-answer session. The training involved 208 students, and 126 completed the questionnaires. The majority of the students had good knowledge (80–100%). They correctly identified the types (91%), risk factors (87%), and gained clarity in selected areas. Added benefits were awards, a book of abstracts and summaries, policy brief and continuous professional development points for doctors. This training programme exemplifies the establishment of medical education in the context of the needs of the population to—be served. Full article

This paper aims to uncover a hidden history of Cantonese Christian literature. Written Cantonese has been present since the late Ming dynasty in parallel to the emergence of a distinct Cantonese identity. Western missionaries, for the sake of evangelism, facilitated the development of written Cantonese in South China since the mid-nineteenth century. At that time, missionaries put a lot of effort into translating religious leaflets and booklets, the Bible, the book of prayers, and even Cantonese–English dictionaries. These works contributed to standardizing written Cantonese and indirectly helped to develop Cantonese identity. I will critically examine how Cantonese Christian literature declined for the sake of nationalism, as the first publication of Heheben 和合本 (Mandarin Union Version) in Protestant Christianity in 1919 represented the unification of the Church by using written Mandarin. After elaborating on the unintentional alliance of missionaries with Cantonese in the nineteenth century, in conclusion, I will make a brief comparison of Hong Kong Church in the twentieth and twenty-first centuries, which is inactive in the continuous written Cantonese movement in Hong Kong. Full article

Mesquite (Prosopis spp.) is one of the main plant representatives in regions with a dry climate, and is a fundamental part of the flora of the Mexican arid, with an indisputable importance from ecological, economic and industrial points of view. However, the restrictive factors of dry climates, as well as genetic variability, are sources of the great diversity of mesquite, so its taxonomy is not yet well defined. The present study seeks to determine the diversity of mesquite in the Mexican semi-desert based on the morphometric characterization of its leaves. Methods: Different leaf parameters such as the number, length and width of the leaflets were recorded in 31 well-marked sites in the area, to obtain measures of central tendency and dispersion, and to determine the differences and similarities between the sites, as well as the groups of homogeneous and heterogeneous taxa. Results: Five taxa were identified, of which there were two varieties (Prosopis glandulosa var. glandulosa and Prosopis reptans var. cinerascens), a pure or typical species (Prosopis laevigata) and two hybrids (Prosopis glandulosa var. glandulosa x Prosopis laevigata and Prosopis laevigata x Prosopis glandulosa var. glandulosa). The discriminant analysis indicated that five variables presented the highest percentage of separation or best separated the taxa, so the study was based on the phenogram with the combination of these five variables: (a) length of middle leaflets, (b) length of upper leaflets, (c) spacing of middle leaflets, (d) length/width relationship of middle leaflets and (e) length/width relationship of middle leaflets. Conclusions: Both the traditional taxonomic classification and the cluster and discriminant analyses reflected the same taxa (Prosopis glandulosa var. glandulosa, Prosopis laevigata and Prosopis reptans var. cinerascens) and the existence of hybridization between Prosopis glandulosa var. glandulosa and Prosopis laevigata. Full article

Objectives: A self-constructed valved pulmonary conduit made out of a de-cellularized porcine small intestinal submucosal extracellular matrix biological scaffold was tested in a chronic growing lamb model. Methods: The conduit was implanted in pulmonary valve position in 19 lambs. We monitored clinical, laboratory, and echocardiographic findings until 12 months after surgery. In two animals, euthanasia was planned at nine and twelve months. Pre-mortem chest computed tomography and post-mortem pathologic work up were performed. Data are presented as frequency and percentage, median and range, or mean and standard deviation. Results: Twelve (63.2%) animals survived the perioperative period. Three unexpected deaths occurred during the follow-up period: one due to aspiration pneumonia at 23 days after surgery, and two due to early and late infective endocarditis of the conduit at 18 and 256 days. In the two animals with planned scarification, the pre-mortem CT scan revealed mild or no calcification within the conduit or valve leaflets. In the echocardiographic examination at 12 months, peak and mean systolic pressure gradients across the conduit valve were 6.5 (3–21) mmHg and 3 (2–12) mmHg, while valve regurgitation was none (n = 2), trivial (n = 5), moderate (n = 1), or severe (n = 1). No clinical or laboratory signs of hemolysis were seen. After 12 months of follow-up, the animals’ body weights had increased from 33 (27–38) kg to 53 (38–66) kg (p = 0.010). Conclusions: Implantation of a valved pulmonary conduit in our growing lamb model was feasible. Infective endocarditis of the implanted valved conduit remained a significant complication. Full article

Background and Objectives: The aim of this study was to determine the role of physicians in the intensive intervention and education regarding the smoking cessation of patients undergoing elective surgery under general anaesthesia. Materials and Methods: A randomised prospective study was conducted in family physicians’ clinics in which smokers of both sexes, aged 21–65 years, without cognitive impairments, and who were not addicted to psychoactive substances voluntarily participated. Four weeks preoperatively, 120 smokers were randomised into two equal groups; the intervention group (IG) underwent an intervention for the purpose of smoking cessation and the control group (CG) underwent no intervention. Biochemical tests were performed in order to determine the smoking status of the participants in the phase of randomisation, one week preoperatively, as well as 40, 120, and 180 days and 12 months postoperatively. The examinees of the IG talked to the physician five times and received 140 telephone messages, leaflets, and motivational letters along with the pharmacotherapy, while the participants in the CG received little or no advice on smoking cessation. Results: The results of this study confirmed a significant influence of the intervention and education on the smoking abstinence in the IG compared to the CG (p < 0.001). The smokers in the IG had 7.31 (95% CI: 2.32–23.04) times greater odds of abstinence upon the 12-month follow-up than the smokers in the CG. The smokers in the IG who did not stop smoking had a lower degree of dependence and smoked fewer cigarettes (p < 0.0001) compared to those in the CG, as well as a multiple times higher prevalence of short- and long-term abstinence. Conclusions: It can be concluded that the intensive intervention and education can motivate patients preparing for elective surgery to stop smoking in the short- and long term. Full article