Resident worklife and wellness through the late phase of the pandemic: a mixed methods national survey study.

BACKGROUND: System contributors to resident burnout and well-being have been under-studied. We sought to determine factors associated with resident burnout and identify at risk groups. METHODS: We performed a US national survey between July 15 2022 and April 21, 2023 of residents in 36 specialties in 14 institutions, using the validated Mini ReZ survey with three 5 item subscales: 1) supportive workplace, 2) work pace/electronic medical record (EMR) stress, and 3) residency-specific factors (sleep, peer support, recognition by program, interruptions and staff relationships). Multilevel regressions and thematic analysis of 497 comments determined factors related to burnout. RESULTS: Of 1118 respondents (approximate median response rate 32%), 48% were female, 57% White, 21% Asian, 6% LatinX and 4% Black, with 25% PGY 1 s, 25% PGY 2 s, and 22% PGY 3 s. Programs included internal medicine (15.1%) and family medicine (11.3%) among 36 specialties. Burnout (found in 42%) was higher in females (51% vs 30% in males, p = 0.001) and PGY 2's (48% vs 35% in PGY-1 s, p = 0.029). Challenges included chaotic environments (41%) and sleep impairment (32%); favorable aspects included teamwork (94%), peer support (93%), staff support (87%) and program recognition (68%). Worklife subscales were consistently lower in females while PGY-2's reported the least supportive work environments. Worklife challenges relating to burnout included sleep impairment (adjusted Odds Ratio (aOR) 2.82 (95% CIs 1.94, 4.19), absolute risk difference (ARD) in burnout 15.9%), poor work control (aOR 2.25 (1.42, 3.58), ARD 12.2%) and chaos (aOR 1.73 (1.22, 2.47), ARD 7.9%); program recognition was related to lower burnout (aOR 0.520 (0.356, 0.760), ARD 9.3%). These variables explained 55% of burnout variance. Qualitative data confirmed sleep impairment, lack of schedule control, excess EMR and patient volume as stressors. CONCLUSIONS: These data provide a nomenclature and systematic method for addressing well-being during residency. Work conditions for females and PGY 2's may merit attention first.

Understanding what leaders can do to facilitate healthcare workers' feeling valued: improving our knowledge of the strongest burnout mitigator.

AIM: Feeling valued is a striking mitigator of burnout yet how to facilitate healthcare workers (HCWs) feeling valued has not been adequately studied. This study discovered factors relating to HCWs feeling valued so leaders can mitigate burnout and retain their workforce. METHOD: The Coping with COVID-19 survey, initiated in March 2020 by the American Medical Association, was distributed to 208 US healthcare organisations. Of the respondents, 37 685 physicians, advanced practice clinicians, nurses, and other clinical staff answered questions that assessed burnout, intent to leave and whether they felt valued.Quantitative analysis looked at odds of burnout and intent to leave among the highest versus lowest feeling valued (FV) groups. Open-ended comments provided by 5559 respondents with high or low sense of FV were analysed to understand aspects of work life that contributed to FV. RESULTS: Of 37 685 respondents, 45% felt valued; HCWs who felt highly valued had 8.3 times lower odds of burnout and 10.2 lower odds of intent to leave than those who did not feel valued at all. Qualitative data identified six themes associated with FV: (1) physical safety, (2) compensation and pandemic-related finances, (3) transparent and frequent communication, (4) effective teamwork, (5) empathetic and respectful leaders, and (6) organisational support. CONCLUSION: This US study demonstrates that FV correlates with burnout and intent to leave, yet only 45% of HCWs feel valued. Six themes link to interventions leaders can follow to facilitate HCWs FV and potentially reduce burnout and increase retention for a challenged healthcare workforce.

Human apo-metallothionein 1a is not a random coil: Evidence from guanidinium chloride, high temperature, and acidic pH unfolding studies.

The structures of apo-metallothioneins (apo-MTs) have been relatively elusive due to their fluxional, disordered state which has been difficult to characterize. However, intrinsically disordered protein (IDP) structures are rather diverse, which raises questions about where the structure of apo-MTs fit into the protein structural spectrum. In this paper, the unfolding transitions of apo-MT1a are discussed with respect to the effect of the chemical denaturant GdmCl, temperature conditions, and pH environment. Cysteine modification in combination with electrospray ionization mass spectrometry was used to probe the unfolding transition of apo-MT1a in terms of cysteine exposure. Circular dichroism spectroscopy was also used to monitor the change in secondary structure as a function of GdmCl concentration. For both of these techniques, cooperative unfolding was observed, suggesting that apo-MT1a is not a random coil. More GdmCl was required to unfold the protein backbone than to expose the cysteines, indicating that cysteine exposure is likely an early step in the unfolding of apo-MT1a. MD simulations complement the experimental results, suggesting that apo-MT1a adopts a more compact structure than expected for a random coil. Overall, these results provide further insight into the intrinsically disordered structure of apo-MT.

ESI-MS analysis of Cu(I) binding to apo and Zn7 human metallothionein 1A, 2, and 3 identifies the formation of a similar series of metallated species with no individual isoform optimization for Cu(I).

Metallothioneins (MTs) are cysteine-rich proteins involved in metal homeostasis, heavy metal detoxification, and protection against oxidative stress. Whether the four mammalian MT isoforms exhibit different metal binding properties is not clear. In this paper, the Cu(I) binding properties of the apo MT1A, apo MT2, and apo MT3 are compared and the relative Cu(I) binding affinities are reported. In all three isoforms, Cu4, Cu6, and Cu10 species form cooperatively, and MT1A and MT2 also form a Cu13 species. The Cu(I) binding properties of Zn7-MT1A, Zn7-MT2, and Zn7-MT3 are compared systematically using isotopically pure 63Cu(I) and 68Zn(II). The species formed in each MT isoform were detected through electrospray ionization-mass spectrometry and further characterized using room temperature phosphorescence spectroscopy. The mixed metal Cu, Zn species forming in MT1A, MT2, and MT3 have similar stoichiometries and their emission spectral properties indicate that analogous clusters form in the three isoforms. Three parallel metallation pathways have been proposed through analysis of the detailed Cu, Zn speciation in MT1A, MT2, and MT3. Pathway ① results in Cu5Zn5-MT and Cu9Zn3-MT. Pathway ② involves Cu6Zn4-MT and Cu10Zn2-MT. Pathway ③ includes Cu8Zn4-MT. Speciation analysis indicates that Pathway ② is the preferred pathway for MT2. This is also evident in the phosphorescence spectra with the 750 nm emission from Cu6Zn4-MT being most prominent in MT2. We see no evidence for different MT isoforms being optimized or exhibiting preferences for certain metals. We discuss the probable stoichiometry for MTs in vivo based on the in vitro determined binding constants.

Physician and Advanced Practice Clinician Burnout in Rural and Urban Settings.

INTRODUCTION: Recruiting rural-practicing clinicians is a high priority. In this study, we explored burnout and contributing work conditions among rural, urban, and family practice physicians and advanced practice clinicians (APCs) in an Upper Midwestern health care system. METHODS: The Mini Z burnout reduction measure was administered by anonymous electronic survey in March 2022. We conducted bivariate analyses of study variables, then assessed relationships of study variables to burnout with multivariate binary logistic regression. RESULTS: Of 1118 clinicians (63% response rate), 589 physicians and 496 APCs were included in this study (n = 1085). Most were female (56%), physicians (54%), and White (86%), while 21% were in family practice, 46% reported burnout, and 349 practiced rurally. Rural and urban clinician burnout rates were comparable (45% vs 47%). Part-time work protected against burnout for family practice and rural clinicians, but not urban clinicians. In multivariate models for rural clinicians, stress (OR: 8.53, 95% CI: 4.09 to 17.78, P < .001), lack of workload control (OR: 3.06, 95% CI: 1.47-6.36, P = .003), busy/chaotic environments (OR: 2.53, 95% CI: 1.29-4.99, P = .007), and intent to leave (OR: 2.18, 95% CI: 1.06-4.45, P = .033) increased burnout odds. In family practice clinicians, stress (OR: 13.43 95% CI: 4.90-36.79, P < .001) also significantly increased burnout odds. CONCLUSIONS: Burnout was comparable between rural and urban physicians and APCs. Part-time work was associated with decreased burnout in rural and family practice clinicians. Addressing burnout drivers (stress, workload control, chaos) may improve rural work environments, reduce turnover, and aid rural clinician recruitment. Addressing stress may be particularly impactful in family practice.

Bi(III) Binding Stoichiometry and Domain-Specificity Differences Between Apo and Zn(II)-bound Human Metallothionein 1a.

Bismuth is a xenobiotic metal with a high affinity to sulfur that is used in a variety of therapeutic applications. Bi(III) induces the cysteine-rich metallothionein (MT), a protein known to form two-domain cluster structures with certain metals such as Zn(II), Cd(II), or Cu(I). The binding of Bi(III) to MTs has been previously studied, but there are conflicting reports on the stoichiometry and binding pathway, which appear to be highly dependent on pH and initial metal-loading status of the MT. Additionally, domain specificity has not been thoroughly investigated. In this paper, ESI-MS was used to determine the binding constants of [Bi(EDTA)]- binding to apo-MT1a and its individual αMT fragment. The results were compared to previous experiments using ßMT1a and ßαMT3. Domain specificity was investigated using proteolysis methods and the initial cooperatively formed Bi2MT was found to bind to cysteines that spanned across the traditional metal binding domain regions. Titrations of [Bi(EDTA)]- into Zn7MT were performed and were found to result in a maximum stoichiometry of Bi7MT, contrasting the Bi6MT formed when [Bi(EDTA)]- was added to apo-MT. These results show that the initial structure of the apo-MT determines the stoichiometry of new incoming metals and explains the previously observed differences in stoichiometry.

Association of Burnout With Primary Care Clinician Perception of Team-Based Scheduling Support.

INTRODUCTION: Primary care clinician burnout is pervasive and detrimental. How components of teamwork and clinic culture might contribute to burnout remains unsettled. OBJECTIVE: To examine associations between primary care clinician perceptions of specific components of teamwork and of organizational culture, and perceived stress and burnout. METHODS: Cross-sectional survey study of primary care clinicians from 5 county health system clinics. Measures: Perceptions of teamwork related to coordination of care, and clinic provision of chronic disease self-management support; values alignment and workplace equity; and demographics. DATA ANALYSIS: Descriptive statistics and Spearman's correlations to examine associations, controlling for clinic and examining response variability by clinic. RESULTS: Of 72 clinicians, 64% were female and 32% non-white. About 56% had worked at least 4 years and half worked 5 to 6 half days/week or more in their clinic. Clinicians who reported having someone on the clinician's care team routinely schedule follow-up appointments for patients with complex chronic illnesses reported lower stress and burnout. Those who perceived greater values alignment with their clinic and greater personal and employee equitable treatment had lower stress and burnout. CONCLUSIONS: Teamwork among clinicians and non-clinical staff, a component of teamwork that is not well-considered in current literature, could be an important piece of the puzzle to decrease the persistent and challenging issue of stress and burnout among primary care clinicians.

Structural motifs in the early metallation steps of Zn(II) and Cd(II) binding to apo-metallothionein 1a.

Many proteins require a metal cofactor to function and these metals are often involved in the protein folding process. The protein metallothionein (MT) has a dynamic structure capable of binding to a variety of metals with different stoichiometries. The most well-understood structure is the seven-metal, two domain structure formed upon metallation using Zn(II) or Cd(II). However, the partially metallated states and the pathways to form these clusters are less well-understood, although it is known that the pathways are pH dependent. Using stopped flow methods, it is shown that the metallation rates of the less cooperative Zn(II) binding pathway is much more impacted by low pH conditions that that of the more cooperative Cd(II) binding pathway. Electrospray ionization mass spectrometry (ESI-MS) methods reveal specific mixtures of bridging and terminally bound MxSy structures form in the first few metallation steps. Using a combination of methods, the data show that the result of unfolding this intrinsically disordered apo-MT structure using guanidinium chloride is that the formation of preliminary bridging structures that form in the first few metallation steps is impeded. The data show that more terminally bound structures form. Our conclusion is that the compact conformation of the native apo-MT at physiological pH allows for rapid formation of complex metal-thiolate structures with high affinity that provides protection from oxidation, a function that is suppressed upon unfolding. Overall, these results highlight both the importance of the apo-MT structure in the metallation pathway, but also the differences in Zn(II) and Cd(II) binding under different conditions.

Supermetalation of Cd-MT3 beyond the two-domain model.

The flexibility of mammalian metallothioneins (MTs) has contributed to the difficulty in obtaining structural information for this family of metalloproteins that bind divalent metals with its twenty cysteines. While the two-domain structure for Cd7MT is well-established as a Cd4S11 and Cd3S9, a third structure has been reported when 8 Cd(II) ions bind to MT1. Isoform 3 of the MT family, MT3, has been of interest to the research community since its isolation as a growth inhibitory factor isolated in brain tissue, and has since been noted as a prominent participant in the mediation of neurodegenerative diseases and regular brain development. The differences between MT3 and the other isoforms of MT include an additional hexapeptide insertion of acidic residues in the α domain as well as the introduction of two prolines in the ß domain. It is unclear whether these changes impact the metalation properties of MT3. We report the formation of a Cd8MT3 species is characterized by electrospray ionization mass spectrometry and UV-visible absorption spectroscopy. We report that the spectroscopic properties of this supermetalated Cd8MT3 are similar to those of the supermetalated Cd8MT1, with a clear indication of changes in structure from "fully-metalated" Cd7MT3 to supermetalated Cd8MT3 from circular dichroism spectra and both 1D 113Cd and 2D 1H-113Cd HSQC NMR spectra. We conclude that the metalation properties are not impacted significantly due to the amino acid changes in MT3, and that the cysteinyl thiols are the key players in determining the capacity of metal-binding and the structure of metal-thiolate clusters.

Cu(I) binds to Zn7-MT2 via two parallel pathways.

Metallothionein proteins are essential for Cu(I) and Zn(II) homeostasis as well as heavy metal detoxification. The metallation properties of MT2 are of great interest due to their wide patterns of expression and correlation with multiple diseases including cancers, neurological disorders, and respiratory diseases. Use of isotopically pure 63Cu(I) and 68Zn(II) eliminates the complexity of the Cu, Zn-MT2 mass spectral peaks due to significant overlap of naturally abundant isotopes. This allows for the resolution of the precise Cu(I) and Zn(II) stoichiometries when both Cu(I) and Zn(II) are bound to MT2 at physiological pH as expected in vivo. Exact Cu: Zn ratios were determined from mass spectral simulations carried out for every point in the titration. We report that Cu(I) metallation of Zn7-MT2 can only be understood in terms of two pathways occurring in parallel with pathway ① resulting in Cu5Zn5-MT2 and Cu9Zn3-MT2. Pathway ② results in Cu6Zn4-MT2 and Cu10Zn2-MT2, which are the major products of the reaction. From the electrospray ionization (ESI)-mass spectral data we report a series of formation constants (KF) for species starting from Zn7-MT2 up to Cu11Zn2-MT2. Room temperature phosphorescence and circular dichroism (CD) spectra were measured in parallel with the ESI-mass spectrometry data allowing for the assignment of specific species to specific spectral bands. Through analysis of the CD spectral bands, we propose that Cu(I) binds to the ß domain first to form a Cu5Zn1 cluster or Cu6 cluster with emission at 670 and 750 nm, respectively, leaving the Zn4 cluster in the α domain.

Metallothionein-3 and carbonic anhydrase metalation properties with Zn(II) and Cd(II) change as a result of protein-protein interactions.

Metallothioneins (MT) are regulators of the metals Zn(II) and Cu(I) and act as antioxidants in many organisms, including in humans. Isoform 3 (MT3) is expressed constitutively in central nervous tissue and has been shown to have additional biological functions, including the inhibition of neuronal growth, the regulation of apoptosis, and cytoskeleton modulation. To facilitate these functions, protein-protein interactions likely occur. These interactions may then impact the metalation status of the MT and the recipient metalloprotein. Using electrospray ionization mass spectrometry and circular dichroism spectroscopy, we report that the interaction between the zinc metalloenzyme, carbonic anhydrase (CA), and MT3, impacts the metalation profiles of both apo-MT3 and apo-CA with Cd(II) and Zn(II). We observe two phases in the metalation of the apo-CA, the first of which is associated with an increased binding affinity of apo-CA for Cd/Zn(II) and the second pathway is associated with apo-CA metalated without a change in binding affinity. The weak interactions that result in this change of binding affinity are not detectable as a protein complex in the ESI-mass spectral data or in the circular dichroism spectra. These unusual metalation properties of apo-CA in the presence of apo-MT3 are evidence of the effects of protein-protein interactions. With adjustment to take into account the interaction of both proteins, we report the complete Cd(II) and Zn(II) binding constants of MT3 under physiological conditions, as well as the pH dependence of these binding pathways.

Xenobiotic Bi3+ Coordination by Cysteine-Rich Metallothionein-3 Reveals a Cooperatively Formed Thiolate-Sharing Bi2S5 Cluster.

The field of designing artificial metalloproteins has yet to effectively tackle the incorporation of multimetal clusters, which is a key component of natural metalloproteins, such as metallothioneins (MTs) and calmodulin. MT is a physiological, essential, cysteine-rich metalloprotein that binds to a variety of metals but is only known to form metal-thiolate clusters with Cd2+, Zn2+, and Cu+. Bismuth is a xenobiotic metal and a component of metallodrugs used to treat gastric ulcers and cancer, as well as an emerging metal used in industrial practices. Electrospray ionization mass spectrometry, UV-visible spectroscopy, and extended X-ray absorption fine structure spectroscopy were used to probe the Bi3+ binding site structures in apo-MT3 (brain-located MT) at pH 7.4 and 2 and provide the complete set of binding affinities. We discovered the highly cooperative formation of a novel Bi3+ species, Bi2MT3, under physiological conditions, where each Bi3+ ion is coordinated by three cysteinyl thiolates, with one of the thiolates bridging between the two Bi3+ ions. This cluster structure was associated with a strong visible region absorption band, which was disrupted by the addition of Zn2+ and reversibly disrupted by acidification and increased temperature. This is the first reported presence of bridging cysteines for a xenobiotic metal in MT3 and the Bi2MT structure is the first Bi cluster found in a metalloprotein.

Teamwork measure relates to provider experience, burnout, and intent to stay.

OBJECTIVES: To develop a brief teamwork measure and determine how teamwork relates to provider experience, burnout, and work intentions. STUDY DESIGN: Survey of clinicians. METHODS: We analyzed data from Optum's 2019 biannual clinician survey, including a validated burnout measure and measures of provider experience and intent to stay. A 6-item measure of team effectiveness (TEAM) focused on efficiency, communication, continuous improvement, and leadership. Construct validity was assessed with content, reliability, and correlation with burnout. Generalized estimating equations with robust SEs determined relationships among TEAM score, provider experience, and intent to stay, controlling for demographics, clustering, and practice factors. RESULTS: Of 1500 physicians and advanced practice clinicians (1387 with complete data; response rate 56%), there were 58% in primary care; 57% were women, and 38% identified as Asian, Black/Hispanic, or another race/ethnicity other than White non-Hispanic. Burnout was present in 30%. The Cronbach α was excellent (0.86), and TEAM correlated with the validated burnout measure (adjusted odds ratio [OR] of lower burnout with high TEAM score, 0.28; 95% CI, 0.19-0.40; P < .0001). Clinicians with TEAM scores of at least 4 were more likely to have positive provider experiences (79% favorable vs 24% with low TEAM score; P < .001), had lower burnout rates (17% vs 44%%; P < .001), and more often intended to stay (93% vs 65%; P < .001). TEAM index score was strongly associated with provider experience (adjusted OR, 11.72; 95% CI, 8.11-16.95; P < .001) and intent to stay (adjusted OR, 7.24; 95% CI, 5.34-9.83; P < .001). CONCLUSIONS: The TEAM index is related to provider experience, burnout, and intent to stay, and it may help organizations optimize clinical work environments.

Arsenic binding to human metallothionein-3.

Arsenic poisoning is of great concern with respect to its neurological toxicity, which is especially significant for young children. Human exposure to arsenic occurs worldwide from contaminated drinking water. In human physiology, one response to toxic metals is through coordination with the metallochaperone metallothionein (MT). Central nervous system expression of MT isoform 3 (MT3) is thought to be neuroprotective. We report for the first time on the metalation pathways of As3+ binding to apo-MT3 under physiological conditions, yielding the absolute binding constants (log Kn, n = 1-6) for each sequential As3+ binding event: 10.20, 10.02, 9.79, 9.48, 9.06, and 8.31 M-1. We report on the rate of the reaction of As3+ with apo-MT3 at pH 3.5 with rate constants (kn, n = 1-6) determined for each sequential As3+ binding event: 116.9, 101.2, 85.6, 64.0, 43.9, and 21.0 M-1 s-1. We further characterize the As3+ binding pathway to fully metalated Zn7MT3 and partially metalated Zn-MT3. As3+ binds rapidly with high binding constants under physiological conditions in a noncooperative manner, but is unable to replace the Zn2+ in fully-metalated Zn-MT3. As3+ binding to partially metalated Zn-MT3 takes place with a rearrangement of the Zn-binding profile. Our work shows that As 3+ rapidly and efficiently binds to both apo-MT3 and partially metalated Zn-MT3 at physiological pH.

Metallothionein-3: 63 Cu(I) binds to human 68 Zn7 -ßα MT3 with no preference for Cu4 -ß cluster formation.

Human metallothioneins (MTs) are involved in binding the essential elements, Cu(I) and Zn(II), and the toxic element, Cd(II), in metal-thiolate clusters using 20 reduced cysteines. The brain-specific MT3 binds a mixture of Cu(I) and Zn(II) in vivo. Its metallation properties are critically important because of potential connections between Cu, Zn and neurodegenerative diseases. We report that the use of isotopically pure 63 Cu(I) and 68 Zn(II) greatly enhances the element resolution in the ESI-mass spectral data revealing species with differing Cu:Zn ratios but the same total number of metals. Room temperature phosphorescence and circular dichroism spectral data measured in parallel with ESI-mass spectral data identified the presence of specific Cu(I)-thiolate clusters in the presence of Zn(II). A series of Cu(I)-thiolate clusters form following Cu(I) addition to apo MT3: the two main clusters that form are a Cu6 cluster in the ß domain followed by a Cu4 cluster in the α domain. 63 Cu(I) addition to 68 Zn7 -MT3 results in multiple species, including clustered Cu5 Zn5 -MT3 and Cu9 Zn3 -MT3. We assign the domain location of the metals for Cu5 Zn5 -MT3 as a Cu5 Zn1 -ß cluster and a Zn4 -α cluster and for Cu9 Zn3 -MT3 as a Cu6 -ß cluster and a Cu3 Zn3 -α cluster. While many reports of the average MT3 metal content exist, determining the exact Cu,Zn stoichiometry has proven very difficult even with native ESI-MS. The work in this paper solves the ambiguity introduced by the overlap of the naturally abundant Cu(I) and Zn(II) isotopes. Contrary to other reports, there is no indication of a major fraction of Cu4 -ß-Znn -α-MT3 forming.

Structural Role of Cadmium and Zinc in Metallothionein Oxidation by Hydrogen Peroxide: The Resilience of Metal-Thiolate Clusters.

Oxidative stress is a state involving an imbalance of reactive oxygen species in a cell and is linked to a variety of diseases. The metal-binding protein metallothionein (MT) may play a role in protection due to its high cysteine content. Many studies have shown that oxidative stress will cause MT to both form disulfide bonds and release bound metals. However, studies on the more biologically relevant partially metalated MTs have been largely neglected. Additionally, most studies to date have used spectroscopic methods that cannot detect specific intermediate species. In this paper, we describe the oxidation and the subsequent metal displacement pathway of fully and partially metalated MTs with hydrogen peroxide. The rates of the reactions were monitored using electrospray ionization mass spectrometry (ESI-MS) techniques, which resolved and characterized the individual intermediate Mx(SH)yMT species. The rate constants were calculated for each species formation. Through ESI-MS and circular dichroism spectroscopy, it was found that the three metals in the ß-domain were the first to be released from the fully metalated MTs. The Cd(II) in the partially metalated Cd(II)-bound MTs rearranged to form a protective Cd4MT cluster structure upon exposure to oxidation. The partially metalated Zn(II)-bound MTs oxidized at a faster rate as the Zn(II) did not rearrange in response to oxidation. Additionally, density functional theory calculations showed that the terminally bound cysteines were more negative and thus more susceptible to oxidation than the bridging cysteines. The results of this study highlight the importance of metal-thiolate structures and metal identity in MT's response to oxidation.

Apo-metallothionein-3 cooperatively forms tightly compact structures under physiological conditions.

Metallothioneins (MTs) are essential mammalian metal chaperones. MT isoform 1 (MT1) is expressed in the kidneys and isoform 3 (MT3) is expressed in nervous tissue. For MTs, the solution-based NMR structure was determined for metal-bound MT1 and MT2, and only one X-ray diffraction structure on a crystallized mixed metal-bound MT2 has been reported. The structure of solution-based metalated MT3 is partially known using NMR methods; however, little is known about the fluxional de novo apo-MT3 because the structure cannot be determined by traditional methods. Here, we used cysteine modification coupled with electrospray ionization mass spectrometry, denaturing reactions with guanidinium chloride, stopped-flow methods measuring cysteine modification and metalation, and ion mobility mass spectrometry to reveal that apo-MT3 adopts a compact structure under physiological conditions and an extended structure under denaturing conditions, with no intermediates. Compared with apo-MT1, we found that this compact apo-MT3 binds to a cysteine modifier more cooperatively at equilibrium and 0.5 times the rate, providing quantitative evidence that many of the 20 cysteines of apo-MT3 are less accessible than those of apo-MT1. In addition, this compact apo-MT3 can be identified as a distinct population using ion mobility mass spectrometry. Furthermore, proposed structural models can be calculated using molecular dynamics methods. Collectively, these findings provide support for MT3 acting as a noninducible regulator of the nervous system compared with MT1 as an inducible scavenger of trace metals and toxic metals in the kidneys.

63Cu(I) binding to human kidney 68Zn7-ßα MT1A: determination of Cu(I)-thiolate cluster domain specificity from ESI-MS and room temperature phosphorescence spectroscopy.

Mammalian metallothioneins (MTs) are important proteins in Zn(II) and Cu(I) homeostasis with the Zn(II) and Cu(I) binding to the 20 cysteines in metal-thiolate clusters. Previous electrospray ionization (ESI) mass spectrometric (MS) analyses of Cu(I) binding to Zn7-MT were complicated by significant overlap of the natural abundance isotopic patterns for Zn(II) and Cu(I) leading to impossibly ambiguous stoichiometries. In this paper, isotopically pure 63Cu(I) and 68Zn(II) allowed determination of the specific stoichiometries in the 68 Zn,63Cu-ßα MT1A species formed following the stepwise addition of 63Cu(I) to 68Zn7-ßα MT1A. These species were characterized by ESI-MS and room temperature emission spectroscopy. The key species that form and their emission band centres are Zn5Cu5-ßα MT1A (λ = 684 nm), Zn4Cu6-ßα MT1A (λ = 750 nm), Zn3Cu9-ßα MT1A (λ = 750 nm), Zn2Cu10-ßα MT1A (λ = 750 nm), and Zn1Cu14-ßα MT1A (λ = 634 nm). The specific domain stoichiometry of each species was determined by assessing the species forming following 63Cu(I) addition to the 68Zn3-ß MT1A and 68Zn4-α MT1A domain fragments. The domain fragment emission suggests that Zn5Cu5-ßα MT1A contains a Zn1Cu5-ß cluster and the Zn4Cu6-ßα MT1A, Zn3Cu9-ßα MT1A, and Zn2Cu10-ßα MT1A each contain a Cu6-ß cluster. The species forming with >10 mol. eq. of 63Cu(I) in ßα-MT1A exhibit emission from the Cu6-ß cluster and an α domain cluster. This high emission intensity is seen at the end of the titrations of 68Zn7-ßα MT1A and the 68Zn4-α MT1A domain fragment suggesting that the initial presence of the Zn(II) results in clustered Cu(I) binding in the α domain.

Trends in Clinician Burnout With Associated Mitigating and Aggravating Factors During the COVID-19 Pandemic.

Importance: The COVID-19 pandemic has affected clinician health and retention. Objective: To describe trends in burnout from 2019 through 2021 with associated mitigating and aggravating factors. Design, Setting, and Participants: Cross-sectional surveys were sent to physicians and advanced practice clinicians throughout 120 large US health care organizations between February 2019 and December 2021. From 56 090 surveys, there were 20 627 respondents. Exposures: Work conditions and COVID-19. Main Outcomes and Measures: Surveys measured time pressure, chaos, work control, teamwork, electronic health record use, values alignment, satisfaction, burnout, intent to leave, and in 2021, feeling valued. Multivariate regressions controlling for gender, race and ethnicity, years in practice, and role determined burnout, satisfaction, and intent-to-leave correlates. Results: Of the 20 627 respondents (median response rate, 58% [IQR, 34%-86%; difference, 52%]), 67% were physicians, 51% female, and 66% White. Burnout was 45% in 2019, 40% to 45% in early 2020, 50% in late 2020, and 60% in late 2021. Intent to leave increased from 24% in 2019 to more than 40% as job satisfaction decreased. Higher burnout was seen in chaotic workplaces (odds ratio [OR], 1.51; 95% CI, 1.38-1.66; P < .001) and with low work control (OR, 2.10; 95% CI, 1.91-2.30; P < .001). Higher burnout was associated with poor teamwork (OR, 2.08; 95% CI, 1.78-2.43; P < .001), while feeling valued was associated with lower burnout (OR, 0.22; 95% CI, 0.18-0.27; P < .001). In time trends, burnout was consistently higher with chaos and poor work control. For example, in the fourth quarter of 2021 burnout was 36% (95% CI, 31%-42%) in calm environments vs 78% (95% CI, 73%-84%) if chaotic (absolute difference, 42%; 95% CI, 34%-49%; P < .001), and 39% (95% CI, 33%-44%) with good work control vs 75% (95% CI, 69%-81%) if poor (absolute difference, 36%; 95% CI, 27%-44%; P < .001). Good teamwork was associated with lower burnout rates (49%; 95% CI, 44%-54%) vs poor teamwork (88%; 95% CI, 80%-97%; absolute difference, 39%; 95% CI, 29%-48%; P < .001), as was feeling valued (37%; 95% CI, 31%-44%) vs not feeling valued (69%; 95% CI, 63%-74%; absolute difference, 32%; 95% CI, 22%-39%; P < .001). Conclusions and Relevance: Results of this survey study show that in 2020 through 2021, burnout and intent to leave gradually increased, rose sharply in late 2021, and varied by chaos, work control, teamwork, and feeling valued. Monitoring these variables could provide mechanisms for worker protection.

Establishing Crosswalks Between Common Measures of Burnout in US Physicians.

BACKGROUND: Physician burnout is often assessed by healthcare organizations. Yet, scores from different burnout measures cannot currently be directly compared, limiting the interpretation of results across organizations or studies. OBJECTIVE: To link common measures of burnout to a single metric in psychometric analyses such that group-level scores from different assessments can be compared. DESIGN: Cross-sectional survey. SETTING: US practices. PARTICIPANTS: A total of 1355 physicians sampled from the American Medical Association Physician Masterfile. MAIN MEASURES: We linked the Stanford Professional Fulfillment Index (PFI) and Mini-Z Single-Item Burnout (MZSIB) scale to the Maslach Burnout Inventory (MBI) in item response theory (IRT) fixed-calibration and equipercentile analyses and created crosswalks mapping PFI and MZSIB scores to corresponding MBI scores. We evaluated the accuracy of the results by comparing physicians' actual MBI scores to those predicted by linking and described the closest cut-point equivalencies across scales linked to the same MBI subscale using the resulting crosswalks. KEY RESULTS: IRT linking produced the most accurate results and was used to create crosswalks mapping (1) PFI Work Exhaustion (PFI-WE) and MZSIB scores to MBI Emotional Exhaustion (MBI-EE) scores and (2) PFI Interpersonal Disengagement (PFI-ID) scores to MBI Depersonalization (MBI-DP) scores. The commonly used MBI-EE raw score cut-point of ≥27 corresponded most closely with respective PFI-WE and MZSIB raw score cut-points of ≥7 and ≥3. The commonly used MBI-DP raw score cut-point of ≥10 corresponded most closely with a PFI-ID raw score cut-point of ≥9. CONCLUSIONS: Our findings allow healthcare organizations using the PFI or MZSIB to compare group-level scores to historical, regional, or national MBI scores (and vice-versa).