No evidence for the superiority of 3 T MRI over 1.5 T MRI for diagnosing wrist ligamentous lesions: a systematic review and meta-analysis.

PURPOSES: Our aim was to determine the diagnostic accuracy of native MRI regarding different ligamentous lesions of the wrist and to analyze the influence of technical characteristics, such as field strength, application of fat saturation, 3D sequences, and wrist coils. METHODS: The systematic search was performed using MEDLINE, Embase, and CENTRAL databases. Studies that were published before the 12th of February 2024 were included. All studies comparing the diagnostic accuracy of native wrist MRI to that of wrist arthroscopy for suspected ligamentous lesions were included. Results were analyzed by anatomic localization and technical aspects of the MRI. To assess the quality of included studies, we used the revised QUADAS-2 tool. RESULTS: The systematic search revealed 5,181 articles. Thirty-seven studies, reporting 3893 ligamentous lesions, were eligible for inclusion. The studies displayed heterogeneity in terms of technical conditions, such as field strength, the use of wrist coils, the application of 3D sequences and fat saturation. Research methods also varied. Overall sensitivity and specificity were 0.78 (0.66 - 0.86) and 0.81 (0.70 - 0.89) for 1.5T MRI, while sensitivity was 0.73 (0.68 - 0.78) and specificity was 0.90 (0.59 - 0.98) for 3T MRI. There was no significant difference between the two subgroups (p=0,3807 and p=0,4248). Sensitivity was 0.82 (0.75 - 0.87) for triangular fibrocartilage complex (TFCC) lesions, 0.63 (0.50 - 0.74) for scapholunate ligament (SL) tears, and 0.41 (0.25 - 0.60) for lunotriquetral ligament (LT) lesions. Specificity for TFCC lesions was 0.82 (0.73 - 0.89), for SL tears 0.86 (0.73 - 0.93), and for LT lesions 0.93 (0.81 - 0.98). CONCLUSION: The sensitivity and specificity of MRI is influenced by the anatomic location of the lesion and technical conditions. In terms of diagnostic accuracy, no significant difference was found between 1.5T and 3T MRI. LEVEL OF EVIDENCE: III. Systematic review of Level II. - III.

Prediabetes and poorly controlled type-2 diabetes as risk indicators for peri-implant diseases:A systematic review and meta-analysis.

OBJECTIVE: The study answers the PECO question: "In adults with dental implants (P), do subjects suffering from type-2 diabetes or prediabetes (E) have worse peri-implant conditions (O) than subjects without type-2 diabetes and prediabetes (C)?". Prediabetes (5.7-6.4 % HbA1c), and the different qualities of glycemic control in type-2 diabetes; well-controlled (>8 % HbA1c), and poorly controlled (>8 % HbA1c) individuals; were classified according to the recommendations of the American Diabetes Association. DATA: Predefined search keys were used with search terms including: Dental implant, diabetes mellitus, glycemic control and HbA1c. SOURCES: An electronic search in the MEDLINE, Embase, and Cochrane libraries were conducted without any filters or language restrictions. Additionally, manual search of the reference lists were carried out to identify all relevant articles. STUDY SELECTION: Eligibility criteria were cohort, case-control and cross-sectional studies that answerd our PECO question with at least 1 year of follow-up. From a total of 2660 records, 35 articles (1761 individuals) were included in the analysis. Meta-analytic difference in means for crestal bone loss was 1.2 mm [95 % CI=0.4; 2.1] in patients with prediabetes, 1.8 mm [CI=1.0; 2.7] in poorly controlled patients, whereas 0.4 mm [CI=-0.3; 1.1] in well-controlled individuals. Meta-regression showed that 1 % increase in HbA1c increased crestal bone loss by 0.24 mm. CONCLUSIONS: Within the limitations of the study, patients with poorly controlled type-2 diabetes or prediabetes may have worse peri-implant conditions compared to patients without diabetes and well-controlled type-2 diabetes. Well-controlled type-2 diabetes is not a risk indicator for peri-implant diseases. CLINICAL SIGNIFICANCE: Clinicians should measure blood HbA1c levels when planning implant-supported restorations, thus patients with undiagnosed or poorly controlled type-2 diabetes can be identified, that allows for glycemic level adjustment prior to dental implant surgery, ensuring peri-implant health. PROTOCOL REGISTRATION NUMBER: (CRD42022375263).

Very young and advanced maternal age strongly elevates the occurrence of nonchromosomal congenital anomalies: a systematic review and meta-analysis of population-based studies.

BACKGROUND: Nonchromosomal congenital anomalies (NCAs) are the most common cause of infant mortality and morbidity. The role of maternal age is well known, although the specifics are not thoroughly elucidated in the literature. OBJECTIVE: To evaluate the role of maternal age in the incidence of NCAs and to pinpoint age groups at higher risk to refine screening protocols. STUDY DESIGN: A systematic review and meta-analysis were conducted following the PRISMA 2020 guidelines and Cochrane Handbook. Searches were performed on October 19, 2021, across MEDLINE (via PubMed), Cochrane Library (CENTRAL), and Embase. Population-based studies assessing the impact of maternal age on the incidence of NCAs in pregnant women were included, without restrictions on age range, country, or comorbidities. A random-effects model was used for pooling effect sizes, considering the heterogeneity across studies. RESULTS: From 15,547 studies, 72 were synthesized. Maternal age >35 showed an increased NCA risk (risk ratio [RR]: 1.31, confidence interval [CI]: 1.07 -1.61), rising notably after>40 (RR: 1.44, CI: 1.25 -1.66). The latter changes to 1.25 (CI: 1.08 -1.46) if the co-occurrence of chromosomal aberrations is excluded. Specific anomalies like cleft lip/palate (>40, RR: 1.57, CI: 1.11 -2.20) and circulatory system defects (>40, RR: 1.94, CI: 1.28 -2.93) were significantly associated with advanced maternal age. Conversely, gastroschisis was linked to mothers <20 (RR: 3.08, CI: 2.74 -3.47). CONCLUSION: The study confirms that both very young and advanced maternal ages significantly increase the risk of NCAs. There is a pressing need for age-specific prenatal screening protocols to better detect these anomalies, especially considering the current trend of delayed childbearing. Further research is required to fully understand the impact of maternal age on the prevalence of rarer NCAs.

Antibiotic-Impregnated Ventriculoperitoneal Shunts Decrease Bacterial Shunt Infection: A Systematic Review and Meta-Analysis.

BACKGROUND AND OBJECTIVES: Antibiotic-impregnated shunts seem to be beneficial in preventing bacterial infections and decreasing mortality by effectively inhibiting microbial growth in the shunt system and reducing the risk of shunt-associated infections. This study aimed to evaluate the efficacy of antibiotic-impregnated shunt catheters (AISC) in reducing the incidence of bacterial shunt infection in patients with hydrocephalus. METHODS: The protocol was registered on PROSPERO. A meta-analysis was conducted by searching 3 databases (PubMed, Scopus, CENTRAL) for relevant randomized controlled trials and observational studies. We included all studies published until November 2022 in any language. The primary outcome was the rate of bacterial infections, whereas the rate of shunt failure was our secondary endpoint. Odds ratios (OR) with 95% CI were calculated using a random-effects model. RESULTS: A total of 27 articles with 27 266 shunt operations were included in this study. The results indicated that using AISC is significantly associated with reduction in infections (OR = 0.42; 95% CI: 0.33-0.54). Regarding shunt failure, there was a tendency in favor of AISC use (OR = 0.73; 95% CI: 0.51-1.06). CONCLUSION: Our study provided evidence that AISC is significantly associated with the reduction in the rate of bacterial ventriculoperitoneal-shunt infection. In addition, there was a tendency toward AISC to decrease shunt failure compared with the standard shunt.

Nonoperative Treatment as an Option for Isolated Anterior Cruciate Ligament Injury: A Systematic Review and Meta-analysis.

Background: An anterior cruciate ligament (ACL) tear is a risk factor for early osteoarthritis (OA) onset. Generally, ACL reconstruction (ACLR) is associated with better outcomes. However, there is a lack of evidence regarding the effect of operative versus nonoperative treatment for preventing premature knee OA in isolated ACL tears while achieving good functional outcomes. Purpose/Hypothesis: The purpose of the study was to compare the outcomes of ACLR to primarily nonoperative management of isolated ACL tears. It was hypothesized that the outcomes between treatment types would be similar. Study Design: Systematic review; Level of evidence, 3. Methods: This systematic review was registered on the International Prospective Register of Systematic Reviews (PROSPERO) (registration No. CRD42021285901) and was conducted according to the Cochrane Handbook guidelines. We systematically searched for randomized and nonrandomized studies that compared ACLR with nonoperative treatments in isolated ACL tears in 3 databases until October 25, 2021. The risk of bias and quality of evidence of the included studies was assessed in accordance with the Cochrane guidelines. The primary outcome was radiologic signs of OA, and the secondary outcomes were functional parameters. Using the common effects model, we calculated pooled mean differences (MDs) and odds ratios (ORs) with 95% CIs. Results: Five studies-2 randomized controlled trials (RCTs) and 3 retrospective non-RCTs-were included. There was a moderate risk of bias in 2 studies and a serious risk of bias in 1 study. The quality of evidence was rated low because of the higher risk of bias and inconsistency. Nonoperatively treated knees showed a trend toward lower odds of developing radiological signs of OA (OR, 1.84 [95% CI, 0.90 to 3.75]); however, surgically reconstructed knees had significantly better stability (MD, -2.44 [95% CI, -3.21 to -1.66 ]) and a trend toward better but clinically not meaningful Lysholm scores (MD, 2.88 [95% CI, -1.09 to 6.85]). The qualitative synthesis showed that surgical reconstruction was protective against subsequent injuries but not superior when returning to previous activity levels or various functional tests. Conclusion: Findings indicated that there is no certain evidence that ACLR for an isolated ACL tear is superior to nonoperative treatment. Clinicians should consider nonoperative treatments with a well-designed rehabilitative program as a primary option. However, these findings must be interpreted with caution because of low study quality and high risk of bias.

Hyaluronate acid plus platelet-rich plasma is superior to steroids for pain relief less than 6 months using injection therapy of partial rotator cuff tears: A systematic review and network meta-analysis.

PURPOSE: We conducted our network meta-analysis to compare the efficacy of the steroid injections to other injectable therapies in partial-thickness rotator cuff tears (PTRCTs). METHODS: A systematic literature search was performed until October 25, 2021 in three databases (CENTRAL, Embase, MEDLINE). Eligible studies compared the efficacy of steroid, hyaluronic acid (HA), platelet-rich plasma (PRP), the combination of HA and PRP (HA+PRP), and adipose-derived regenerative cells (ADRC) in RC tears. The primary outcomes were the Visual Analogue Scale (VAS), Constant Murley Score (CMS), and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form. Using paired and network meta-analysis, we calculated pooled mean differences (MDs) with 95% confidence intervals (CIs). RESULTS: We included a total of seven articles in the quantitative synthesis. In shorter periods, the HA+PRP combination was superior to the other substances we investigated (HA+PRP: VAS (0-4 weeks): MD: -0.99 [CI = -1.62, -0.36]; CMS (0-3 months): 20.56 [CI = 16.18, 24.94]. This combination was followed by the use of HA or PRP alone, depending on the duration of follow-up and the outcome being studied. In our study, short-term results suggest that saline is superior to steroids for partial tears, but this trend is reversed at six-month follow-up. CONCLUSION: Our results suggest the combination of HA and PRP to be a more effective therapeutic option for partial RC ruptures for short terms, but there is no significant difference after 6 months. LEVEL OF EVIDENCE: II, Included of Level of Evidence studies I-II.

Anisotropy, Anatomical Region, and Additional Variables Influence Young's Modulus of Bone: A Systematic Review and Meta-Analysis.

The importance of finite element analysis (FEA) is growing in orthopedic research, especially in implant design. However, Young's modulus (E) values, one of the most fundamental parameters, can range across a wide scale. Therefore, our study aimed to identify factors influencing E values in human bone specimens. We report our systematic review and meta-analysis based on the recommendation of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guideline. We conducted the analysis on November 21, 2021. We included studies investigating healthy human bone specimens and reported on E values regarding demographic data, specimen characteristics, and measurement specifics. In addition, we included study types reporting individual specimen measurements. From the acquired data, we created a cohort in which we performed an exploratory data analysis that included the explanatory variables selected by random forest and regression trees methods, and the comparison of groups using independent samples Welch's t test. A total of 756 entries were included from 48 articles. Eleven different bones of the human body were included in these articles. The range of E values is between 0.008 and 33.7 GPa. The E values were most heavily influenced by the cortical or cancellous type of bone tested. Measuring method (compression, tension, bending, and nanoindentation), the anatomical region within a bone, the position of the bone within the skeleton, and the bone specimen size had a decreasing impact on the E values. Bone anisotropy, specimen condition, patient age, and sex were selected as important variables considering the value of E. On the basis of our results, E values of a bone change with bone characteristics, measurement techniques, and demographic variables. Therefore, the evaluation of FEA should be performed after the standardization of in vitro measurement protocol. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Obesity and Ankle Prosthesis Revision: A Systematic Review and Meta-analysis.

BACKGROUND: The increasing number of total ankle arthroplasties (TAAs) has led to growing evidence on the risk factors for complications after surgery. However, the role of obesity in this patient group has been the subject of much debate. Therefore, this systematic review aimed to investigate the evidence for untoward effects of obesity following TAA. METHODS: We conducted a comprehensive search on April 28, 2023, in MEDLINE (via PubMed), Embase, and CENTRAL. Eligible observational studies reported on the short- and long-term outcomes of primary TAA, comparing patients with and without obesity (defined as body mass index > 30). Using a random effects model, we calculated pooled odds ratios (ORs) with 95% confidence intervals (CIs) from 2 by 2 tables (event and nonevent in the obese and nonobese primary TAA groups). RESULTS: Nine studies with 10 388 patients were eligible for inclusion in the meta-analysis. We found significantly higher odds of revision in the obese group compared to the nonobese group (OR = 1.68, CI: 1.44-1.95). However, the odds of overall perioperative complications (OR = 1.55, CI: 0.50-4.80) and wound complications (OR = 1.34, CI: 0.29-6.20) were nonsignificantly higher in the obese group. CONCLUSION: Based on our results, obesity may have affected long-term outcomes following TAA and may have negatively affected the prosthesis's survival.

Association of tumor location with anxiety and depression in childhood brain cancer survivors: a systematic review and meta-analysis.

OBJECTIVE: This study aimed to evaluate the association between the location (supratentorial or infratentorial) of brain tumors and the development of depression and anxiety in childhood cancer survivors. Understanding the risk factors for the development of depression and anxiety disordersin these patients is crucial for early diagnosis and successful treatment. METHODS: The meta-analysis included articles that listed patients diagnosed with an intracranial tumor before the age of 18 years, provided the location of the tumor, had exact data on the prevalence of anxiety and depression, or measured these disorders using different assessment tools. The search was conducted in five different databases (MEDLINE, Embase, Web of Science, Scopus, and Cochrane Library). Risk of bias was assessed using QUIPS-2. Outcome measures used were prevalences and standardized means. RESULTS: The analysis included 42 eligible articles with a total number of 1071 patients. Relevant articles were cohort studies, cross-sectional studies, and case series. Based on the available data infratentorial brain tumor survivors had significantly higher scores on various assessment tools measuring anxiety (MRAW (raw mean scores): 36.24 [CI (confidence interval): 28.81-43.67]; versus MRAW: 23.21 (CI 0.91-45.51); p = 0.02, and depression (MRAW: 27.57 (CI 14.35-40.78) versus MRAW: 13.84 (CI 11.43-16.26); p < 0.01. CONCLUSION: Childhood infratentorial cancer survivors have more impairments in terms of depression and anxiety; these children and adults should be monitored more frequently and may require closer follow-up on their mental health. The main limitation of our study originates from the lack of data on follow-up times used by different studies.

Determination of the Main Phase Transition Temperature of Phospholipids by Oscillatory Rheology.

Knowledge of the physical and chemical properties of phospholipids, such as phase transition temperatures (Tc), is of great importance in order to reveal the functionalities of biological and artificial membranes. Our research group developed an oscillatory rheological method for the simple and rapid determination of phase transition temperatures (Tc). The phospholipids constructing the membranes undergo conformational changes at their Tc, which cause alterations of viscoelastic properties of the molecules. The oscillatory technique recommended by us proved to be appropriate to reveal the altered molecular properties of phospholipids as tracking the slightest changes in the viscoelasticity. Our study demonstrates the abrupt changes in rheological properties at Tc for the following phospholipids: 1,2-Dimyristoyl-sn-glycero-3-Phosphocholine (DMPC), 1,2-Dipalmitoyl-sn-glycero-3-Phosphatidylcholine (DPPC), and 1,2-Distearoyl-sn-glycero-3-Phosphocholine (DSPC), proving that the applied methodology is adequate for determining the Tc of phospholipids.

Subvastus Approach Supporting Fast-Track Total Knee Arthroplasty Over the Medial Parapatellar Approach: A Systematic Review and Network Meta-Analysis.

BACKGROUND: Numerous surgical approaches are being used to perform total knee arthroplasty (TKA). This systematic review and network meta-analysis aimed to compare surgical approaches used in TKA regarding postoperative outcomesat different time points. METHODS: We performed a literature search from medical database inception until October 2, 2021. We searched for randomized controlled trials (RCTs) investigating patients undergoing TKA and comparing at least 2 surgical approaches regarding early postsurgical clinical outcomes (range of motion [ROM], pain on a visual analog scale, and Knee Society Score [KSS]). We included 33 RCTs in our networks. Using paired and network meta-analysis, we calculated pooled mean differences (MDs) with 95% CIs by comparing surgical approaches to the medial parapatellar method. RESULTS: The subvastus (SV) method performed the best on days 1 (MD = 6.99; CI: 1.08; 12.89), 3 (MD = 8.00; CI: 2.08; 13.92), 4 (MD = 27.01; CI: 18.09; 35.92), and 6 (MD = 27.22; CI: 18.38; 36.07) for ROM improvement. Regarding the decrease in pain, the mini SV approach offered significantly lower pain values on days 1 (MD = -1.98; CI: -2.93; -1.03), 3 (MD = -0.85; CI: -1.49; -0.22), and 7 (MD = -1.90; CI: -2.23; -1.57). The differences decreased as time passed. Furthermore, the SV and mini-SV methods performed the best regarding total, knee and function KSS. CONCLUSION: Quadriceps-sparing approaches, especially the SV and mini-SV, are superior to the other approaches in the early postsurgical period, but the differences decrease as time passes.

Maternal age is highly associated with non-chromosomal congenital anomalies: Analysis of a population-based case-control database.

OBJECTIVE: The role of maternal age in the development of non-chromosomal congenital anomalies (NCAs) is under debate. Therefore, the primary aim of this study was to identify the age groups at risk for NCAs. The secondary aim was to perform a detailed analysis of the relative frequency of various anomalies. DESIGN: National population-based study. SETTING: The Hungarian Case-Control Surveillance of Congenital Anomalies (CAs) between 1980 and 2009. POPULATION OR SAMPLE: A cohort of 31 128 cases with confirmed NCAs was compared with Hungary's total of 2 808 345 live births. METHODS: Clinicians prospectively reported cases after delivery. Data were analysed by non-linear logistic regression. Risk-increasing effect of young and advanced maternal age was determined by each NCA group. MAIN OUTCOME MEASURES: These were the total number of NCAs: cleft lip and palate, circulatory, genital, musculoskeletal, digestive, urinary, eye, ear, face, and neck, nervous system, and respiratory system anomalies. RESULTS: The occurrence of NCAs in our database was lowest between 23 and 32 years of maternal age at childbirth. The relative risk (RR) of any NCA was 1.2 (95% CI 1.17-1.23) and 1.15 (95% CI 1.11-1.19) in the very young and advanced age groups, respectively. The respective results for the circulatory system were RR = 1.07 (95% CI 1.01-1.13) and RR = 1.33 (95% CI 1.24-1.42); for cleft lip and palate RR = 1.09 (95% CI 1.01-1.19) and RR = 1.45 (95% CI 1.26-1.67); for genital organs RR = 1.15 (95% CI 1.08-1.22) and RR = 1.16 (95% CI 1.04-1.29); for the musculoskeletal system RR = 1.17 (95% CI 1.12-1.23) and RR = 1.29 (95% CI 1.14-1.44); and for the digestive system RR = 1.23 (95% CI 1.14-1.31) and RR = 1.16 (95% CI 1.04-1.29). CONCLUSION: Very young and advanced maternal ages are associated with different types of NCAs. Therefore, screening protocols should be adjusted for these risk groups.

Transcatheter aortic valve replacement ­ 10 years experience at Gottsegen György National Cardiovascular Center in Hungary / Tíz év tapasztalatai a transzkatéteres aortamubillentyu-implantációval a Gottsegen György Országos Kardiovaszkuláris Intézetben.

Összefoglaló. Bevezetés: A transzkatéteres aortamubillentyu-beültetés (TAVI) az idos, súlyos aortastenosisban szenvedo, multimorbid, magas mutéti kockázattal rendelkezo betegek esetében javasolt a szívsebészeti aortamubillentyu-beültetés alternatívájaként. Célkituzés: Jelen munkánkban az intézetünkben elindult TAVI-program elso 10 éve alatt elvégzett 463, TAVI-n átesett beteg rövid és hosszú távú eredményeit tekintjük át és értékeljük. Külön vizsgáljuk az elso 200 beteg és az utánuk következo 263 beteg eredményeit. Módszer: 2008. november 11. és 2018. december 31. között 463 betegnél végeztünk TAVI-t. Betegeink átlagéletkora 79,6 év, átlagos logisztikus EuroSCORE-értékük 19,0%, átlagos STS-score-értékük pedig 5,2% volt. A beavatkozás elott az esetek 72%-ában NYHA III-as vagy IV-es funkcionális stádiumban voltak. A beavatkozások 92,8%-át transfemoralis behatolásból végeztük. Az aortabillentyun mért átlagos gradiens 50 Hgmm, a billentyuarea 0,55 cm2 volt. Az esetek mintegy 2%-ában az aortabillentyu-bioprotézis restenosisa miatt "valve-in-valve" beavatkozást végeztünk. Eredmények: A TAVI után a 30 napos halálozás 5,2%, az 1 éves pedig 16,4% volt. A TAVI-t követoen kialakult szövodményeket a VARC-2 kritériumrendszere alapján értékeltük. A beavatkozás után 2,2%-ban fordult elo major stroke. A leggyakoribb szövodmény, a posztoperatív pacemakerimplantáció (19,9%) aránya szignifikánsan csökkent a késobb TAVI-n átesett 263 beteg esetében (26,5% vs. 14,8% [p = 0,002]). A vérzéses szövodmények aránya a percutan beavatkozások bevezetésével szignifikánsan emelkedett ugyan (10% vs. 20,2% [p = 0,016]), de ez nem járt a mortalitás emelkedésével. Következtetés: Az eredmények alapján elmondhatjuk, hogy a TAVI intézetünkben is biztonságos alternatívát jelent a magas mutéti rizikóval rendelkezo, súlyos, tünetes aortastenosisban szenvedo betegek esetében. Orv Hetil. 2022; 163(6): 229-235. INTRODUCTION: Transcatheter aortic valve implantation (TAVI) is an alternative treatment to surgical aortic valve replacement for elderly, high surgical risk patients. OBJECTIVE: The aim of this study was to evaluate the short- and long-term outcomes of those 463 patients who underwent TAVI during the first 10 years in our TAVI program. We compare the first 200 patients' results with the further 263 patients' results. METHOD: Between 11th November 2008 and 31st December 2018, 463 patients underwent TAVI. The average age of the patients was 79.6 years, the average logistic EuroSCORE was 19.0%, the average STS score was 5.2%. 72% of the patients were in NYHA III or IV stage before TAVI. 92% of TAVIs were performed from femoral arteries. Average mean gradient was 50.0 mmHg and aortic valve area was 0.55 cm2, respectively. In 2% of the cases, "valve-in-valve" intervention was performed because of the restenosis of former aortic valve prosthesis. RESULTS: 30-day mortality was 5.2% and the 1-year mortality was 16.4% after TAVI. Post-TAVI complications were evaluated according to the VARC-2 definitions. Major stroke occurred in 2.2% after TAVI. The most common complication was pacemaker implantation (19.9%), but their incidence was significantly reduced between the 2 groups (26.5% vs. 14.8% [p = 0.002]). The incidence of vascular access site complications was significantly higher between the 2 groups (10% vs. 20.2% [p = 0.016]), but it did not affect the mortality. CONCLUSION: Based on our results, TAVI is a safe alternative treatment for patients with severe, symptomatic aortic stenosis in our institute as well. Orv Hetil. 2022; 163(6): 229-235.

Label-free Multiscale Transport Imaging of the Living Cell.

The living cell is characterized by a myriad of parallel intracellular transport processes. Simultaneously capturing their global features across multiple temporal and spatial scales is a nearly unsurmountable task. Here we present a method that enables the microscopic imaging of the entire spectrum of intracellular transport on a broad time scale without the need for prior labeling. We show that from the time-dependent fluctuation of pixel intensity, in either bright-field or phase-contrast microscopic images, a scaling factor can be derived that reflects the local Hurst coefficient (H), the value of which reveals the microscopic mechanisms of intracellular motion. The Hurst coefficient image of the interphase cell displays an unexpected, overwhelming superdiffusion (H > 0.5) in the cytoplasm and subdiffusion (H < 0.5) in the nucleus, and provides unprecedented sensitivity in detecting transport processes associated with the living state.

Comparing the folding and misfolding energy landscapes of phosphoglycerate kinase.

Partitioning of polypeptides between protein folding and amyloid formation is of outstanding pathophysiological importance. Using yeast phosphoglycerate kinase as model, here we identify the features of the energy landscape that decide the fate of the protein: folding or amyloidogenesis. Structure formation was initiated from the acid-unfolded state, and monitored by fluorescence from 10 ms to 20 days. Solvent conditions were gradually shifted between folding and amyloidogenesis, and the properties of the energy landscape governing structure formation were reconstructed. A gradual transition of the energy landscape between folding and amyloid formation was observed. In the early steps of both folding and misfolding, the protein searches through a hierarchically structured energy landscape to form a molten globule in a few seconds. Depending on the conditions, this intermediate either folds to the native state in a few minutes, or forms amyloid fibers in several days. As conditions are changed from folding to misfolding, the barrier separating the molten globule and native states increases, although the barrier to the amyloid does not change. In the meantime, the native state also becomes more unstable and the amyloid more stable. We conclude that the lower region of the energy landscape determines the final protein structure.

Recovery of functional enzyme from amyloid fibrils.

Amyloid deposits, which accumulate in numerous diseases, are the final stage of multi-step protein conformational-conversion and oligomerization processes. The underlying molecular mechanisms are not fully understood, and particularly little is known about the reverse reaction. Here we show that phosphoglycerate kinase amyloid fibrils can be converted back into native protein. We achieved recovery with 60% efficiency, which is comparable to the success rate of the unfolding-refolding studies, and the recovered enzyme was folded, stable and fully active. The key intermediate stages in the recovery process are fibril disassembly and unfolding followed by spontaneous protein folding.

Domain interactions direct misfolding and amyloid formation of yeast phosphoglycerate kinase.

There are proteins that are built of two structural domains and are deposited full-length in amyloid plaques formed in various diseases. In spite of the known differences in the mechanisms of folding of single- and multidomain proteins, no published studies can be found that address the role of the domain-domain interactions during misfolding and amyloid formation. By the discovery of the role of domain-domain interactions, here we provide important insight in the submolecular mechanism of amyloid formation. A model system based on yeast phosphoglycerate kinase was designed. This system includes the wild-type yeast phosphoglycerate kinase and single-tryptophan mutants of the individual N and C terminal domains and the complete protein. Electron microscopic measurements proved that amyloid fibrils grow from all mutants under identical conditions as for the wild-type protein. Misfolding and amyloid formation was followed in stopped-flow and manual mixing experiments on the 1 ms to 4 days timescale. Tryptophan fluorescence was used for selective detection of conformational changes accompanying the formation of the amyloidogenic intermediates and the growth of amyloid fibrils. The interactions between the polypeptide chains of the two domains direct the misfolding process from the early steps to the amyloid formation, and influence the final structure. The kinetics of misfolding is different for the individual domains, pointing to the significance of the amino acid sequence. Misfolding of the domains within the complete protein is synchronized indicating that domain-domain interactions direct the misfolding and amyloid formation mechanism.