Dynein structure and power stroke

Dynein ATPases are microtubule motors that are critical to diverse processes such as vesicle transport and the beating of sperm tails; however, their mechanism of force generation is unknown. Each dynein comprises a head, from which a stalk and a stem emerge. Here we use electron microscopy and image processing to reveal new structural details of dynein c, an isoform from Chlamydomonas reinhardtii flagella, at the start and end of its power stroke. Both stem and stalk are flexible, and the stem connects to the head by means of a linker approximately 10 nm long that we propose lies across the head. With both ADP and vanadate bound, the stem and stalk emerge from the head 10 nm apart. However, without nucleotide they emerge much closer together owing to a change in linker orientation, and the coiled-coil stalk becomes stiffer. The net result is a shortening of the molecule coupled to an approximately 15-nm displacement of the tip of the stalk. These changes indicate a mechanism for the dynein power stroke

Validation of deep learning techniques for quality augmentation in diffusion MRI for clinical studies

The objective of this study is to evaluate the efficacy of deep learning (DL) techniques in improving the quality of diffusion MRI (dMRI) data in clinical applications. The study aims to determine whether the use of artificial intelligence (AI) methods in medical images may result in the loss of critical clinical information and/or the appearance of false information. To assess this, the focus was on the angular resolution of dMRI and a clinical trial was conducted on migraine, specifically between episodic and chronic migraine patients. The number of gradient directions had an impact on white matter analysis results, with statistically significant differences between groups being drastically reduced when using 21 gradient directions instead of the original 61. Fourteen teams from different institutions were tasked to use DL to enhance three diffusion metrics (FA, AD and MD) calculated from data acquired with 21 gradient directions and a b-value of 1000 s/mm2. The goal was to produce results that were comparable to those calculated from 61 gradient directions. The results were evaluated using both standard image quality metrics and Tract-Based Spatial Statistics (TBSS) to compare episodic and chronic migraine patients. The study results suggest that while most DL techniques improved the ability to detect statistical differences between groups, they also led to an increase in false positive. The results showed that there was a constant growth rate of false positives linearly proportional to the new true positives, which highlights the risk of generalization of AI-based tasks when assessing diverse clinical cohorts and training using data from a single group. The methods also showed divergent performance when replicating the original distribution of the data and some exhibited significant bias. In conclusion, extreme caution should be exercised when using AI methods for harmonization or synthesis in clinical studies when processing heterogeneous data in clinical studies, as important information may be altered, even when global metrics such as structural similarity or peak signal-to-noise ratio appear to suggest otherwise

Trypanosoma cruzi Gene Expression in Response to Gamma Radiation

Trypanosoma cruzi is an organism highly resistant to ionizing radiation. Following a dose of 500 Gy of gamma radiation, the fragmented genomic DNA is gradually reconstructed and the pattern of chromosomal bands is restored in less than 48 hours. Cell growth arrests after irradiation but, while DNA is completely fragmented, RNA maintains its integrity. In this work we compared the transcriptional profiles of irradiated and non-irradiated epimastigotes at different time points after irradiation using microarray. In total, 273 genes were differentially expressed; from these, 160 were up-regulated and 113 down-regulated. We found that genes with predicted functions are the most prevalent in the down-regulated gene category. Translation and protein metabolic processes, as well as generation of precursor of metabolites and energy pathways were affected. In contrast, the up-regulated category was mainly composed of obsolete sequences (which included some genes of the kinetoplast DNA), genes coding for hypothetical proteins, and Retrotransposon Hot Spot genes. Finally, the tyrosyl-DNA phosphodiesterase 1, a gene involved in double-strand DNA break repair process, was up-regulated. Our study demonstrated the peculiar response to ionizing radiation, raising questions about how this organism changes its gene expression to manage such a harmful stress

Emergency hernia repair in the elderly. multivariate analysis of morbidity and mortality from an Italian registry

Purpose The incidence of inguinal hernia is higher in elderly because of aging-related diseases like prostatism, bronchitis, collagen laxity. A conservative management is common in elderly to reduce surgery-related risks, however watchful waiting can expose to obstruction and strangulation. The aim of the present study was to assess the impact of emergency surgery in a large series of elderly with complicated groin hernia and to identify the independent risk factors for postoperative morbidity and mortality. The predictive performance of prognostic risk scores has been also assessed. Methods This is a prospective observational study carried out between January 2017 and June 2018 in elderly patients who underwent emergency surgery for complicated hernia in 38 Italian hospitals. Pre-operative, surgical and postoperative data were recorded for each patient. ASA score, Charlson's comorbidity index, P-POSSUM and CR-POSSUM were assessed. Results 259 patients were recruited, mean age was 80 years. A direct repair without mesh was performed in 62 (23.9%) patients. Explorative laparotomy was performed in 56 (21.6%) patients and bowel resection was necessary in 44 (17%). Mortality occurred in seven (2.8%) patients. Fifty-five (21.2%) patients developed complications, 12 of whom had a major one. At univariate and multivariate analyses, Charlson's comorbidity index >= 6, altered mental status, and need for laparotomy were associated with major complications and mortality Conclusion Emergency surgery for complicated hernia is burdened by high morbidity and mortality in elderly patients. Preoperative comorbidity played a pivotal role in predicting complications and mortality and therefore Charlson's comorbidity index could be adopted to select patients for elective operation

Perforated peptic ulcer (PPU) treatment: an Italian nationwide propensity score-matched cohort study investigating laparoscopic vs open approach

BackgroundPerforated peptic ulcer (PPU) remain a surgical emergency accounting for 37% of all peptic ulcer-related deaths. Surgery remains the standard of care. The benefits of laparoscopic approach have been well-established even in the elderly. However, because of inconsistent results with specific regard to some technical aspects of such technique surgeons questioned the adoption of laparoscopic approach. This leads to choose the type of approach based on personal experience. The aim of our study was to critically appraise the use of the laparoscopic approach in PPU treatment comparing it with open procedure.MethodsA retrospective study with propensity score matching analysis of patients underwent surgical procedure for PPU was performed. Patients undergoing PPU repair were divided into: Laparoscopic approach (LapA) and Open approach (OpenA) groups and clinical-pathological features of patients in the both groups were compared.ResultsA total of 453 patients underwent PPU simple repair. Among these, a LapA was adopted in 49% (222/453 patients). After propensity score matching, 172 patients were included in each group (the LapA and the OpenA). Analysis demonstrated increased operative times in the OpenA [OpenA: 96.4 +/- 37.2 vs LapA 88.47 +/- 33 min, p = 0.035], with shorter overall length of stay in the LapA group [OpenA 13 +/- 12 vs LapA 10.3 +/- 11.4 days p = 0.038]. There was no statistically significant difference in mortality [OpenA 26 (15.1%) vs LapA 18 (10.5%), p = 0.258]. Focusing on morbidity, the overall rate of 30-day postoperative morbidity was significantly lower in the LapA group [OpenA 67 patients (39.0%) vs LapA 37 patients (21.5%) p = 0.002]. When stratified using the Clavien-Dindo classification, the severity of postoperative complications was statistically different only for C-D 1-2.ConclusionsBased on the present study, we can support that laparoscopic suturing of perforated peptic ulcers, apart from being a safe technique, could provide significant advantages in terms of postoperative complications and hospital stay

Metabolic Syndrome (MetS), Systemic Inflammatory Response Syndrome (SIRS), and Frailty: Is There any Room for Good Outcome in the Elderly Undergoing Emergency Surgery?

Background: Patients with MetS or SIRS experience higher rates of mortality and morbidity, across both cardiac and noncardiac surgery. Frailty assessment has acquired increasing importance in recent years as it predisposes elderly patients to a worse outcome. The aim of our study was to investigate the influence of MetS, SIRS, and with or without frailty on elderly patients undergoing emergency surgical procedures. Methods: We analyzed data of all patients with nonmalignant diseases requiring an emergency surgical procedure from January 2017 to December 2020. The occurrence of MetS was identified using modified definition criteria used by the NCEP-ATP III Expert Panel: obesity, hypertension, diabetes, or if medication for high triglycerides or for low HDL cholesterol was taken. Systemic inflammatory response syndrome (SIRS) was evaluated according to the original consensus study (Sepsis-1). The frailty profile was investigated by the 5-modified Frailty Index (5-mFI) and the Emergency Surgery Frailty Index (EmSFI). Postoperative complications have been reported and categorized according to the Clavien–Dindo (C–D) classification system. Morbidity and mortality have been mainly considered as the 30-day standard period definition. Results: Of the 2,318 patients included in this study, 1,010 (43.6%) fulfilled the criteria for MetS (MetsG group). Both 5-Items score and EmsFI showed greater fragility in patients with MetS. All patients with MetS showed more frequently a CACI index greater than 6. The occurrence of SIRS was higher in MetSG. LOS was longer in patients with MetS (MetSG 11.4 ± 12 days vs. n-MetSG 10.5 ± 10.2 days, p = 0.046). MetSG has a significantly higher rate of morbidity (353 (35.%) vs. 385 (29.4%), p = 0.005). The mortality rate in patients with MetS (98/1010, 10%) was similar to that in patients without it (129/1308, 10%). Considering patients with MetS who developed SIRS and those who had frailty or both, the occurrence of these conditions was associated with a higher rate of morbidity and mortality. Conclusion: Impact of MetS and SIRS on elderly surgical patient outcomes has yet to be fully elucidated. The present study showed a 43.6% incidence of MetS in the elderly population. In conclusion, age per se should be not considered anymore as the main variable to estimate patient outcomes, while MetS and Frailty should have always a pivotal role

Gastro-intestinal emergency surgery: Evaluation of morbidity and mortality. Protocol of a prospective, multicenter study in Italy for evaluating the burden of abdominal emergency surgery in different age groups. (The GESEMM study)

Gastrointestinal emergencies (GE) are frequently encountered in emergency department (ED), and patients can present with wide-ranging symptoms. more than 3 million patients admitted to US hospitals each year for EGS diagnoses, more than the sum of all new cancer diagnoses. In addition to the complexity of the urgent surgical patient (often suffering from multiple co-morbidities), there is the unpredictability and the severity of the event. In the light of this, these patients need a rapid decision-making process that allows a correct diagnosis and an adequate and timely treatment. The primary endpoint of this Italian nationwide study is to analyze the clinicopathological findings, management strategies and short-term outcomes of gastrointestinal emergency procedures performed in patients over 18. Secondary endpoints will be to evaluate to analyze the prognostic role of existing risk-scores to define the most suitable scoring system for gastro-intestinal surgical emergency. The primary outcomes are 30-day overall postoperative morbidity and mortality rates. Secondary outcomes are 30-day postoperative morbidity and mortality rates, stratified for each procedure or cause of intervention, length of hospital stay, admission and length of stay in ICU, and place of discharge (home or rehabilitation or care facility). In conclusion, to improve the level of care that should be reserved for these patients, we aim to analyze the clinicopathological findings, management strategies and short-term outcomes of gastrointestinal emergency procedures performed in patients over 18, to analyze the prognostic role of existing risk-scores and to define new tools suitable for EGS. This process could ameliorate outcomes and avoid futile treatments. These results may potentially influence the survival of many high-risk EGS procedure

Reciprocal learning and chronic care model implementation in primary care: results from a new scale of learning in primary care

<p>Abstract</p> <p>Background</p> <p>Efforts to improve the care of patients with chronic disease in primary care settings have been mixed. Application of a complex adaptive systems framework suggests that this may be because implementation efforts often focus on education or decision support of individual providers, and not on the dynamic system as a whole. We believe that learning among clinic group members is a particularly important attribute of a primary care clinic that has not yet been well-studied in the health care literature, but may be related to the ability of primary care practices to improve the care they deliver.</p> <p>To better understand learning in primary care settings by developing a scale of learning in primary care clinics based on the literature related to learning across disciplines, and to examine the association between scale responses and chronic care model implementation as measured by the Assessment of Chronic Illness Care (ACIC) scale.</p> <p>Methods</p> <p>Development of a scale of learning in primary care setting and administration of the learning and ACIC scales to primary care clinic members as part of the baseline assessment in the ABC Intervention Study. All clinic clinicians and staff in forty small primary care clinics in South Texas participated in the survey.</p> <p>Results</p> <p>We developed a twenty-two item learning scale, and identified a five-item subscale measuring the construct of reciprocal learning (Cronbach alpha 0.79). Reciprocal learning was significantly associated with ACIC total and sub-scale scores, even after adjustment for clustering effects.</p> <p>Conclusions</p> <p>Reciprocal learning appears to be an important attribute of learning in primary care clinics, and its presence relates to the degree of chronic care model implementation. Interventions to improve reciprocal learning among clinic members may lead to improved care of patients with chronic disease and may be relevant to improving overall clinic performance.</p

Drosophila Dynein Intermediate Chain Gene, Dic61B, Is Required for Spermatogenesis

This study reports the identification and characterization of a novel gene, Dic61B, required for male fertility in Drosophila. Complementation mapping of a novel male sterile mutation, ms21, isolated in our lab revealed it to be allelic to CG7051 at 61B1 cytogenetic region, since two piggyBac insertion alleles, CG7051c05439 and CG7051f07138 failed to complement. CG7051 putatively encodes a Dynein intermediate chain. All three mutants, ms21, CG7051c05439 and CG7051f07138, exhibited absolute recessive male sterility with abnormally coiled sperm axonemes causing faulty sperm individualization as revealed by Phalloidin staining in Don Juan-GFP background. Sequencing of PCR amplicons uncovered two point mutations in ms21 allele and confirmed the piggyBac insertions in CG7051c05439 and CG7051f07138 alleles to be in 5′UTR and 4th exon of CG7051 respectively, excision of which reverted the male sterility. In situ hybridization to polytene chromosomes demonstrated CG7051 to be a single copy gene. RT-PCR of testis RNA revealed defective splicing of the CG7051 transcripts in mutants. Interestingly, expression of cytoplasmic dynein intermediate chain, α, β, γ tubulins and α-spectrin was normal in mutants while ultra structural studies revealed defects in the assembly of sperm axonemes. Bioinformatics further highlighted the homology of CG7051 to axonemal dynein intermediate chain of various organisms, including DNAI1 of humans, mutations in which lead to male sterility due to immotile sperms. Based on these observations we conclude that CG7051 encodes a novel axonemal dynein intermediate chain essential for male fertility in Drosophila and rename it as Dic61B. This is the first axonemal Dic gene of Drosophila to be characterized at molecular level and shown to be required for spermatogenesis