Deciphering the Substrate Specificity of SbnA, the Enzyme Catalyzing the First Step in Staphyloferrin B Biosynthesis.

Staphylococcus aureus assembles the siderophore, staphyloferrin B, from l-2,3-diaminopropionic acid (l-Dap), α-ketoglutarate, and citrate. Recently, SbnA and SbnB were shown to produce l-Dap and α-ketoglutarate from O-phospho-l-serine (OPS) and l-glutamate. SbnA is a pyridoxal 5'-phosphate (PLP)-dependent enzyme with homology to O-acetyl-l-serine sulfhydrylases; however, SbnA utilizes OPS instead of O-acetyl-l-serine (OAS), and l-glutamate serves as a nitrogen donor instead of a sulfide. In this work, we examined how SbnA dictates substrate specificity for OPS and l-glutamate using a combination of X-ray crystallography, enzyme kinetics, and site-directed mutagenesis. Analysis of SbnA crystals incubated with OPS revealed the structure of the PLP-α-aminoacrylate intermediate. Formation of the intermediate induced closure of the active site pocket by narrowing the channel leading to the active site and forming a second substrate binding pocket that likely binds l-glutamate. Three active site residues were identified: Arg132, Tyr152, Ser185 that were essential for OPS recognition and turnover. The Y152F/S185G SbnA double mutant was completely inactive, and its crystal structure revealed that the mutations induced a closed form of the enzyme in the absence of the α-aminoacrylate intermediate. Lastly, l-cysteine was shown to be a competitive inhibitor of SbnA by forming a nonproductive external aldimine with the PLP cofactor. These results suggest a regulatory link between siderophore and l-cysteine biosynthesis, revealing a potential mechanism to reduce iron uptake under oxidative stress.

Comparing the Efficacy of Large Language Models ChatGPT, BARD, and Bing AI in Providing Information on Rhinoplasty: An Observational Study.

Background: Large language models (LLMs) are emerging artificial intelligence (AI) technologies refining research and healthcare. However, the impact of these models on presurgical planning and education remains under-explored. Objectives: This study aims to assess 3 prominent LLMs-Google's AI BARD (Mountain View, CA), Bing AI (Microsoft, Redmond, WA), and ChatGPT-3.5 (Open AI, San Francisco, CA) in providing safe medical information for rhinoplasty. Methods: Six questions regarding rhinoplasty were prompted to ChatGPT, BARD, and Bing AI. A Likert scale was used to evaluate these responses by a panel of Specialist Plastic and Reconstructive Surgeons with extensive experience in rhinoplasty. To measure reliability, the Flesch Reading Ease Score, the Flesch-Kincaid Grade Level, and the Coleman-Liau Index were used. The modified DISCERN score was chosen as the criterion for assessing suitability and reliability. A t test was performed to calculate the difference between the LLMs, and a double-sided P-value <.05 was considered statistically significant. Results: In terms of reliability, BARD and ChatGPT demonstrated a significantly (P < .05) greater Flesch Reading Ease Score of 47.47 (±15.32) and 37.68 (±12.96), Flesch-Kincaid Grade Level of 9.7 (±3.12) and 10.15 (±1.84), and a Coleman-Liau Index of 10.83 (±2.14) and 12.17 (±1.17) than Bing AI. In terms of suitability, BARD (46.3 ± 2.8) demonstrated a significantly greater DISCERN score than ChatGPT and Bing AI. In terms of Likert score, ChatGPT and BARD demonstrated similar scores and were greater than Bing AI. Conclusions: BARD delivered the most succinct and comprehensible information, followed by ChatGPT and Bing AI. Although these models demonstrate potential, challenges regarding their depth and specificity remain. Therefore, future research should aim to augment LLM performance through the integration of specialized databases and expert knowledge, while also refining their algorithms.

Inhibition of myocardial cathepsin-L release during reperfusion following myocardial infarction improves cardiac function and reduces infarct size.

AIMS: Identifying novel mediators of lethal myocardial reperfusion injury that can be targeted during primary percutaneous coronary intervention (PPCI) is key to limiting the progression of patients with ST-elevation myocardial infarction (STEMI) to heart failure. Here, we show through parallel clinical and integrative preclinical studies the significance of the protease cathepsin-L on cardiac function during reperfusion injury. METHODS AND RESULTS: We found that direct cardiac release of cathepsin-L in STEMI patients (n = 76) immediately post-PPCI leads to elevated serum cathepsin-L levels and that serum levels of cathepsin-L in the first 24 h post-reperfusion are associated with reduced cardiac contractile function and increased infarct size. Preclinical studies demonstrate that inhibition of cathepsin-L release following reperfusion injury with CAA0225 reduces infarct size and improves cardiac contractile function by limiting abnormal cardiomyocyte calcium handling and apoptosis. CONCLUSION: Our findings suggest that cathepsin-L is a novel therapeutic target that could be exploited clinically to counteract the deleterious effects of acute reperfusion injury after an acute STEMI.

Head and neck subcutaneous emphysema, a rare complication of iatrogenic perforation during colonoscopy: management review of reported cases from 2000-2016.

INTRODUCTION: Subcutaneous face and neck emphysema secondary to colonic perforation is a rare complication of colonoscopy. Presentation may be complicated by pneumothorax and/or respiratory distress. Evidence limited to case studies. Therefore, no management consensus of these rarely reported cases exists. METHODS: All cases published on PubMed between 1 January 2000-1 November 2016 reporting subcutaneous face and/or neck emphysema after colonoscopy are included. Management is discussed with trends identified. We report a case of a patient undergoing routine polypectomy who developed subcutaneous emphysema of the face, neck and thorax with a pneumothorax and pneumoretroperitoneum. RESULTS: 37 cases were found (mean age = 64.1 ± 15.09 years). The majority (n = 24) were managed non-operatively. Conservative and operative management had mean inpatient stays of 7.6 ± 4.65 and 19.5 +/- 21.62 days respectively. Sixteen cases had a concomitant pneumothorax with nine (56.3%) requiring decompression. No mortalities occurred. CONCLUSION: An understanding of anatomy heightens awareness of the rare complication of face and/or neck surgical emphysema, secondary to pneumoretroperitoneum and pneumothorax, after perforation of the colon during endoscopy. Management remains controversial with expectant conservative bowel rest with antibiotics and operative intervention described. Conservative management had a shorter inpatient stay and was more common in younger patients.

Rehabilitation outcomes in the older adult.

Numerous studies support the use of rehabilitative interventions in the older adult. Given the many fiscal challenges in health care today, it is of utmost importance that funding for rehabilitation result in fruitful outcomes. Specific rehabilitative interventions have been found to be very effective in the elderly and can be demonstrated through numerous studies. Outcomes for conditions including stroke, traumatic brain injury, spinal cord injury, amputation, hip fracture, and joint replacement are discussed. There is great need for ongoing research to determine optimal rehabilitative interventions in the elderly.

Academic requirements for Certificate of Completion of Training in surgical training: Consensus recommendations from the Association of Surgeons in Training/National Research Collaborative Consensus Group.

BACKGROUND: Surgical trainees are expected to demonstrate academic achievement in order to obtain their certificate of completion of training (CCT). These standards are set by the Joint Committee on Surgical Training (JCST) and specialty advisory committees (SAC). The standards are not equivalent across all surgical specialties and recognise different achievements as evidence. They do not recognise changes in models of research and focus on outcomes rather than process. The Association of Surgeons in Training (ASiT) and National Research Collaborative (NRC) set out to develop progressive, consistent and flexible evidence set for academic requirements at CCT. METHODS: A modified-Delphi approach was used. An expert group consisting of representatives from the ASiT and the NRC undertook iterative review of a document proposing changes to requirements. This was circulated amongst wider stakeholders. After ten iterations, an open meeting was held to discuss these proposals. Voting on statements was performed using a 5-point Likert Scale. Each statement was voted on twice, with ≥80% of votes in agreement meaning the statement was approved. The results of this vote were used to propose core and optional academic requirements for CCT. RESULTS: Online discussion concluded after ten rounds. At the consensus meeting, statements were voted on by 25 delegates from across surgical specialties and training-grades. The group strongly favoured acquisition of 'Good Clinical Practice' training and research methodology training as CCT requirements. The group agreed that higher degrees, publications in any author position (including collaborative authorship), recruiting patients to a study or multicentre audit and presentation at a national or international meeting could be used as evidence for the purpose of CCT. The group agreed on two essential 'core' requirements (GCP and methodology training) and two of a menu of four 'additional' requirements (publication with any authorship position, presentation, recruitment of patients to a multicentre study and completion of a higher degree), which should be completed in order to attain CCT. CONCLUSION: This approach has engaged stakeholders to produce a progressive set of academic requirements for CCT, which are applicable across surgical specialties. Flexibility in requirements whilst retaining a high standard of evidence is desirable.

Ab initio folding simulation of the Trp-cage mini-protein approaches NMR resolution.

Here, we report a 100 ns molecular dynamics simulation of the folding process of a recently designed autonomous-folding mini-protein designated as tc5b with a new AMBER force field parameter set developed based on condensed-phase quantum mechanical calculations and a Generalized Born continuum solvent model. Starting from its fully extended conformation, our simulation has produced a final structure resembling that of NMR native structure to within 1A main-chain root mean square deviation. Remarkably, the simulated structure stayed in the native state for most part of the simulation after it reached the state. Of greater significance is that our simulation has not only reached the correct main-chain conformation, but also a very high degree of accuracy in side-chain packing conformation. This feat has traditionally been a challenge for ab initio simulation studies. In addition to characterization of the trajectory, comparison of our results to experimental data is also presented. Analysis of the trajectory suggests that the rate-limiting step of folding of this mini-protein is the packing of the Trp side-chain.

Delivery of rehabilitation services to people aging with a disability.

The disabled elderly population continues to grow. Systems of care for the disabled elderly are vast, ranging from inpatient facilities to outpatient programs and home programs. Recent advances in technology allow us to reach patients in their homes through telemedicine. Support services within the community are growing, and case managers are becoming more necessary as it becomes more difficult to navigate the health care system. As providers of rehabilitative services, we must help our patients find the most appropriate setting to receive care. As the focus continues to shift from inpatient to outpatient care and to home services, we must approach health care in a dynamic fashion and with flexibility. We must be advocates for our patients and their caretakers. Significant research questions remain, and health care policy requires development. As the population ages and the disabled elderly population become a focus of fiscal experts, we must look to provide the most cost-effective yet functionally productive health care. We may shift from focusing on functional performance in a therapy gym or inpatient rehabilitation unit to functional performance at home. We must focus on IADL and QOL indicators and must strive to find ways to provide efficient, cost-effective care. Medicaid, Medicare, and third-party insurers offer various options. The VHA offers additional benefit to those who are eligible. Advocacy groups such as the American Association of Retired Persons struggle to meet its members' needs and concerns while generating income to provide education and other resources. We must work to promote the strengths of the elderly population by addressing preventive strategies while maintaining functional independence.

Distinguish protein decoys by using a scoring function based on a new AMBER force field, short molecular dynamics simulations, and the generalized born solvent model.

Recent works have shown the ability of physics-based potentials (e.g., CHARMM and OPLS-AA) and energy minimization to differentiate the native protein structures from large ensemble of non-native structures. In this study, we extended previous work by other authors and developed an energy scoring function using a new set of AMBER parameters (also recently developed in our laboratory) in conjunction with molecular dynamics and the Generalized Born solvent model. We evaluated the performance of our new scoring function by examining its ability to distinguish between the native and decoy protein structures. Here we present a systematic comparison of our results with those obtained with use of other physics-based potentials by previous authors. A total of 7 decoy sets, 117 protein sequences, and more than 41,000 structures were evaluated. The results of our study showed that our new scoring function represents a significant improvement over previously published physics-based scoring functions.

Sympathetic vasomotor changes induced by manual and electrical acupuncture of the Hoku point visualized by thermography.

Considerable evidence implicates sympathetic neural activity in acupuncture analgesia. However, the exact nature of these effects has not been specified in detail, and many experimental findings are contradictory. This study evaluated in normal conditions the specific sympathetic effects of both manual and electrical acupuncture applied to the same hand (Hoku) point. Thermographic measures of superficial skin temperature were used to assess sympathetic vasomotor tone in the face, hand and foot of 19 normal subjects. Baseline assessment, manual acupuncture and electrical acupuncture were performed in 3 separate sessions in a well controlled, 23 degrees C environment. Superficial skin temperature decreased slowly in the control condition. Both manual and electrical acupuncture produced a generalized long-lasting warming effect, indicating reduced sympathetic activity (sympatholytic effect). In addition, electrical acupuncture induced a localized short-term cooling effect, indicating a transient segmental increase in sympathetic activity (sympathomimetic effect).

Pain perception decrement produced through repeated stimulation.

Pain responses (pain detection and pain discomfort) to electrical dental stimulation were studied in 16 normal subjects. The repetition of the dental stimuli induced a significant and long-lasting (60 min) decrease in pain sensitivity at both sensory levels (after 60 min of repetitive stimulation, 79% increase in pain detection, P less than 0.0001, 45% increase in pain discomfort, P less than 0.0004). The sensory response decrement through repeated elicitation was not influenced by naloxone administration (1.2 mg i.m.). This study clearly demonstrates the induction of pain sensory decrease through repetitive stimulation which differs from peripheral sensory receptor adaptation, from the inhibitory gating mechanism or from diffuse inhibitory controls activation; its unresponsiveness to naloxone suggests that this phenomenon is not opioid-dependent. A technique has been standardized which will enable the systematic study of pain decrease under sustained nociceptive stimulation in chronic pain patients.

Convalescence care for seniors of lower Manhattan: an interdisciplinary outreach, rehabilitation, and education model.

The purpose of this study was to test the efficacy of an interdisciplinary geriatric outreach, rehabilitation, and education program for seniors. Community-dwelling Chinese seniors in lower Manhattan were recruited through outreach activities (17 educational workshops, three community health fairs, media interviews) and community physician referrals to offer rehabilitation services. The instrument administered at entry and exit included questions about pain intensity, quality of life, activities of daily living (ADLs), and an assessment of a variety of intrinsic and extrinsic barriers to life participation. The sample included 70 seniors (53 women) with a mean age of 70.5 +/- 7.48 years (range 60-93 years old) of whom 86% were Cantonese-speaking Chinese. The barriers-to-life participation assessment revealed cultural, communication, transportation, and physical environmental barriers as well as insufficient financial resources. Thirty-four patients who completed the program showed a significant improvement in quality of life. Patients' reports reflected a high degree of satisfaction with the program. Interdisciplinary team-oriented patient care, including a physiatrist, social worker, and rehabilitation staff, may result in good outcomes and high patient satisfaction in ambulatory community seniors.

A point-charge force field for molecular mechanics simulations of proteins based on condensed-phase quantum mechanical calculations.

Molecular mechanics models have been applied extensively to study the dynamics of proteins and nucleic acids. Here we report the development of a third-generation point-charge all-atom force field for proteins. Following the earlier approach of Cornell et al., the charge set was obtained by fitting to the electrostatic potentials of dipeptides calculated using B3LYP/cc-pVTZ//HF/6-31G** quantum mechanical methods. The main-chain torsion parameters were obtained by fitting to the energy profiles of Ace-Ala-Nme and Ace-Gly-Nme di-peptides calculated using MP2/cc-pVTZ//HF/6-31G** quantum mechanical methods. All other parameters were taken from the existing AMBER data base. The major departure from previous force fields is that all quantum mechanical calculations were done in the condensed phase with continuum solvent models and an effective dielectric constant of epsilon = 4. We anticipate that this force field parameter set will address certain critical short comings of previous force fields in condensed-phase simulations of proteins. Initial tests on peptides demonstrated a high-degree of similarity between the calculated and the statistically measured Ramanchandran maps for both Ace-Gly-Nme and Ace-Ala-Nme di-peptides. Some highlights of our results include (1) well-preserved balance between the extended and helical region distributions, and (2) favorable type-II poly-proline helical region in agreement with recent experiments. Backward compatibility between the new and Cornell et al. charge sets, as judged by overall agreement between dipole moments, allows a smooth transition to the new force field in the area of ligand-binding calculations. Test simulations on a large set of proteins are also discussed.