Delayed rib plating and lung herniation repair in a traumatic chest injury after thoracotomy: A case report.

INTRODUCTION AND IMPORTANCE: Lung herniation following trauma is a rare occurrence, and consensus on optimal surgical repair techniques remains limited. While small herniations may resolve without surgery, intervention becomes necessary in cases of unsuccessful non-operative management or concurrent rib fracture stabilization. Mesh application in repair poses a dilemma, often providing physical support but raising infection concerns, particularly in trauma scenarios with delayed closure. Surgical stabilization of rib fractures, employing hardware similar to orthopedic procedures, may necessitate prophylactic antibiotics, though empirical evidence supporting routine use is scant. Polytrauma patients often resort to delayed chest closure techniques during methodical surgical planning, but these carry potential consequences compared to immediate closure. CASE PRESENTATION: Presented is a case involving a patient in a motorcycle collision sustaining multiple injuries, necessitating a massive transfusion protocol, multiple surgeries, including delayed chest closure, and eventual surgical rib fixation four days post-injury. During rib stabilization, exacerbation of traumatic lung herniation mandated mesh repair, prompting the cautious use of prophylactic vancomycin powder to mitigate infection risks. DISCUSSION: A review of the literature revealed a scarcity of similar cases, particularly those involving lung herniation with delayed chest closure, the use of prophylactic antibiotics and mesh in polytrauma. CONCLUSION: This case underscores the lack of depth of comprehensive research guiding surgical decisions concerning lung herniation and the prophylactic use of vancomycin powder in trauma patients.

Outcomes of severely injured pregnant trauma patients: a multicenter analysis.

Nearly 10% of pregnant women suffer traumatic injury. Clinical outcomes for pregnant trauma patients (PTPs) with severe injuries have not been well studied. We sought to describe outcomes for PTPs presenting with severe injuries, hypothesizing that PTPs with severe injuries will have higher rates of complications and mortality compared to less injured PTPs. A post-hoc analysis of a multi-institutional retrospective study at 12 Level-I/II trauma centers was performed. Patients were stratified into severely injured (injury severity score [ISS] > 15) and not severely injured (ISS < 15) and compared with bivariate analyses. From 950 patients, 32 (3.4%) had severe injuries. Compared to non-severely injured PTPs, severely injured PTPs were of similar maternal age but had younger gestational age (21 vs 26 weeks, p = 0.009). Penetrating trauma was more common in the severely injured cohort (15.6% vs 1.4%, p < 0.001). The severely injured cohort more often underwent an operation (68.8% vs 3.8%, p < 0.001), including a hysterectomy (6.3% vs 0.3%, p < 0.001). The severely injured group had higher rates of complications (34.4% vs 0.9%, p < 0.001), mortality (15.6% vs 0.1%, p < 0.001), a higher rate of fetal delivery (37.5% vs. 6.0%, p < 0.001) and resuscitative hysterotomy (9.4% vs. 0%, p < 0.001). Only approximately 3% of PTPs were severely injured. However, severely injured PTPs had a nearly 40% rate of fetal delivery as well as increased complications and mortality. This included a resuscitative hysterotomy rate of nearly 10%. Significant vigilance must remain when caring for this population.

Predictors of fetal delivery in pregnant trauma patients: A multicenter study.

BACKGROUND: Pregnant trauma patients (PTPs) undergo observation and fetal monitoring following trauma due to possible fetal delivery (FD) or adverse outcome. There is a paucity of data on PTP outcomes, especially related to risk factors for FD. We aimed to identify predictors of posttraumatic FD in potentially viable pregnancies. METHODS: All PTPs (≥18 years) with ≥24-weeks gestational age were included in this multicenter retrospective study at 12 Level-I and II trauma centers between 2016 and 2021. Pregnant trauma patients who underwent FD ((+) FD) were compared to those who did not deliver ((-) FD) during the index hospitalization. Univariate analyses and multivariable logistic regression were performed to identify predictors of FD. RESULTS: Of 591 PTPs, 63 (10.7%) underwent FD, with 4 (6.3%) maternal deaths. The (+) FD group was similar in maternal age (27 vs. 28 years, p = 0.310) but had older gestational age (37 vs. 30 weeks, p < 0.001) and higher mean injury severity score (7.0 vs. 1.5, p < 0.001) compared with the (-) FD group. The (+) FD group had higher rates of vaginal bleeding (6.3% vs. 1.1%, p = 0.002), uterine contractions (46% vs. 23.5%, p < 0.001), and abnormal fetal heart tracing (54.7% vs. 14.6%, p < 0.001). On multivariate analysis, independent predictors for (+) FD included abdominal injury (odds ratio [OR], 4.07; confidence interval [CI], 1.11-15.02; p = 0.035), gestational age (OR, 1.68 per week ≥24 weeks; CI, 1.44-1.95; p < 0.001), abnormal FHT (OR, 12.72; CI, 5.19-31.17; p < 0.001), and premature rupture of membranes (OR, 35.97; CI, 7.28-177.74; p < 0.001). CONCLUSION: The FD rate was approximately 10% for PTPs with viable fetal gestational age. Independent risk factors for (+) FD included maternal and fetal factors, many of which are available on initial trauma bay evaluation. These risk factors may help predict FD in the trauma setting and shape future guidelines regarding the recommended observation of PTPs. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level III.

Outcomes for advanced aged (35 and older) versus younger aged pregnant trauma patients: A multicenter study.

BACKGROUND: Effects of advanced maternal age (AMA) pregnancies (defined as ≥35 years) on pregnant trauma patients (PTPs) are unknown. This study compared AMA versus younger PTPs, hypothesizing AMA PTPs have increased risk of fetal delivery (FD). METHODS: A retrospective (2016-2021) multicenter study included all PTPs. Multivariable logistic regression was used to evaluate risk of FD after trauma. RESULTS: A total of 950 PTPs were included. Both cohorts had similar gestational age and injury severity scores. The AMA group had increased injuries to the pancreas, bladder, and stomach (p < 0.05). There was no difference in rate or associated risk of FD between cohorts (5.3% vs. 11.4%; OR 0.59, CI 0.19-1.88, p > 0.05). CONCLUSION: Compared to their younger counterparts, some intra-abdominal injuries (pancreas, bladder, and stomach) were more common among AMA PTPs. However, there was no difference in rate or associated risk of FD in AMA PTPs, thus they do not require increased observation.

Association of socioeconomic status with the clinical management and outcomes in young patients (≤35 years) diagnosed with breast cancer: A retrospective analysis.

Background: Very young breast cancer at 35 years or younger is rare and tends to be aggressive. The management of very young breast cancer should be equally aggressive, and early diagnosis is critical. We hypothesized that socioeconomic status (SES) is associated with how very young breast cancer (VYBC) patients are diagnosed and treated in our community. Methods: We retrospectively analyzed a database for invasive breast cancer or ductal carcinoma in-situ (DCIS) diagnosed ≤35 years old (VYBC) from both a government-run county hospital (CH) and a neighboring private hospital (PH) for 82 months. Inclusion criteria composed of female patients diagnosed with invasive breast cancer and DCIS at ≤35 years of age at diagnosis were examined in our analysis. Patient diagnoses and severity, treatment, and outcomes were compared between the two facilities. The methods are consistent with the STROCSS guidelines. Results: The incidence of VYBC was a significantly higher percentage of new breast cancers diagnosed in the CH at 5.4% as compared to the PH at 1.9% (OR: 2.94; p < 0.001). CH had a significantly higher proportion of Medicaid payers (73% CH vs. 21% PH, p < 0.001). Mean time from patient's initial symptoms until a tissue diagnosis was significantly longer at the county hospital at 9.6 months vs 2.1 months at the private hospital (p < 0.01). Stage I tumors were only found in 13% of county hospital patients versus 67% at the private hospital (p < 0.001). Approximately 63% of the patients at the government-run county facility had a relative delay in diagnosis, contributing to higher stage at presentation. The rate of mastectomy surgery was high at both institutions: CH 83% vs. PH 76% (p = NS). Discussion: The results of our study suggest a significant healthcare difference between county and private hospital systems among very young breast cancer patients. Patients at the county hospital system had a longer delay to diagnosis leading to worse outcomes. This difference may be a reflection of barriers in health literacy or access to medical care.

Convergent Alterations of a Protein Hub Produce Divergent Effects within a Binding Site.

Progress in tumor sequencing and cancer databases has created an enormous amount of information that scientists struggle to sift through. While several research groups have created computational methods to analyze these databases, much work still remains in distinguishing key implications of pathogenic mutations. Here, we describe an approach to identify and evaluate somatic cancer mutations of WD40 repeat protein 5 (WDR5), a chromatin-associated protein hub. This multitasking protein maintains the functional integrity of large multi-subunit enzymatic complexes of the six human SET1 methyltransferases. Remarkably, the somatic cancer mutations of WDR5 preferentially distribute within and around an essential cavity, which hosts the WDR5 interaction (Win) binding site. Hence, we assessed the real-time binding kinetics of the interactions of key clustered WDR5 mutants with the Win motif peptide ligands of the SET1 family members (SET1Win). Our measurements highlight that this subset of mutants exhibits divergent perturbations in the kinetics and strength of interactions not only relative to those of the native WDR5 but also among various SET1Win ligands. These outcomes could form a fundamental basis for future drug discovery and other developments in medical biotechnology.

Decreased hospital length of stay and intensive care unit admissions for non-COVID blunt trauma patients during the COVID-19 pandemic.

BACKGROUND: The COVID-19 pandemic overwhelmed hospitals, forcing adjustments including discharging patients earlier and limiting intensive care unit (ICU) utilization. This study aimed to evaluate ICU admissions and length of stay (LOS) for blunt trauma patients (BTPs). METHODS: A retrospective review of COVID (3/19/20-6/30/20) versus pre-COVID (3/19/19-6/30/19) BTPs at eleven trauma centers was performed. Multivariable analysis was used to identify risk factors for ICU admission. RESULTS: 12,744 BTPs were included (6942 pre-COVID vs. 5802 COVID). The COVID cohort had decreased mean LOS (3.9 vs. 4.4 days, p = 0.029), ICU LOS (0.9 vs. 1.1 days, p < 0.001), and rate of ICU admission (22.3% vs. 24.9%, p = 0.001) with no increase in complications or mortality compared to the pre-COVID cohort (all p > 0.05). On multivariable analysis, the COVID period was associated with decreased risk of ICU admission (OR = 0.82, CI 0.75-0.90, p < 0.001). CONCLUSIONS: BTPs had decreased LOS and associated risk of ICU admission during COVID, with no corresponding increase in complications or mortality.

Effects of the COVID-19 pandemic on pediatric trauma in Southern California.

PURPOSE: The COVID-19 pandemic resulted in increased penetrating trauma and decreased length of stay (LOS) amongst the adult trauma population, findings important for resource allocation. Studies regarding the pediatric trauma population are sparse and mostly single-center. This multicenter study examined pediatric trauma patients, hypothesizing increased penetrating trauma and decreased LOS after the 3/19/2020 stay-at-home (SAH) orders. METHODS: A multicenter retrospective analysis of trauma patients ≤ 17 years old presenting to 11 centers in California was performed. Demographic data, injury characteristics, and outcomes were collected. Patients were divided into three groups based on injury date: 3/19/2019-6/30/2019 (CONTROL), 1/1/2020-3/18/2020 (PRE), 3/19/2020-6/30/2020 (POST). POST was compared to PRE and CONTROL in separate analyses. RESULTS: 1677 patients were identified across all time periods (CONTROL: 631, PRE: 479, POST: 567). POST penetrating trauma rates were not significantly different compared to both PRE (11.3 vs. 9.0%, p = 0.219) and CONTROL (11.3 vs. 8.2%, p = 0.075), respectively. POST had a shorter mean LOS compared to PRE (2.4 vs. 3.3 days, p = 0.002) and CONTROL (2.4 vs. 3.4 days, p = 0.002). POST was also not significantly different than either group regarding intensive care unit (ICU) LOS, ventilator days, and mortality (all p > 0.05). CONCLUSIONS: This multicenter retrospective study demonstrated no difference in penetrating trauma rates among pediatric patients after SAH orders but did identify a shorter LOS.

Understanding the makeup of a growing field: A committee on trauma survey of the national network of hospital-based violence intervention programs.

BACKGROUND: Among Hospital Based Violence Intervention programs (HVIPs), little is known about variation in services provided, funding sources, or populations served. STUDY DESIGN: Twenty-eight member programs of Health Alliance for Violence Intervention participated in a survey administered by the American College of Surgeons Committee on Trauma. Questions were quantitative and qualitative. For qualitative analysis, questions pertaining to the domains were assessed for common themes and assessed across all subject domains. RESULTS: All programs enroll patients injured by community violence, some by intimate partner violence (IPV), trafficking, and rarely by child or elder abuse. Programs with more funding (≥$300,000 per year) were more likely federally, state, or city funded. Lower funded programs (≤$300,000 per year) were funded by foundations or philanthropy. In both qualitative and quantitative analysis, barriers to starting or sustaining HVIPs included funding, and lack of risk reduction and mental health resources. Successful programs had stable funding, adequate staffing, and buy in from hospitals and staff. CONCLUSION: HVIPs serve diverse populations in variable models. There is opportunity to expand the reach of HVIPs, and the experience if existing programs is an invaluable resource.

Complex effects of macrolide venturicidins on bacterial F-ATPases likely contribute to their action as antibiotic adjuvants.

Bacterial energy metabolism is now recognized as a critical factor for the efficacy of antibiotics. The F-type ATPase/ATP synthase (FOF1) is a central player in cellular bioenergetics of bacteria and eukaryotes, and its potential as a selective antibiotic target has been confirmed by the success of bedaquiline in combatting multidrug-resistant tuberculosis. Venturicidin macrolides were initially identified for their antifungal properties and were found to specifically inhibit FOF1 of eukaryotes and bacteria. Venturicidins alone are not effective antibacterials but recently were found to have adjuvant activity, potentiating the efficacy of aminoglycoside antibiotics against several species of resistant bacteria. Here we discovered more complex effects of venturicidins on the ATPase activity of FOF1 in bacterial membranes from Escherichia coli and Pseudomonas aeruginosa. Our major finding is that higher concentrations of venturicidin induce time- and ATP-dependent decoupling of F1-ATPase activity from the venturicidin-inhibited, proton-transporting FO complex. This dysregulated ATPase activity is likely to be a key factor in the depletion of cellular ATP induced by venturicidins in prior studies with P. aeruginosa and Staphylococcus aureus. Further studies of how this functional decoupling occurs could guide development of new antibiotics and/or adjuvants that target the F-type ATPase/ATP synthase.

American Association for the Surgery of Trauma Prevention Committee review: Family Justice Centers-a not-so-novel, but unknown gem.

The American College of Surgeons Committee on Trauma requires that trauma centers demonstrate adequate financial support for an injury prevention program as part of the verification process. With the ongoing challenges that arise with important social determinants of health, trauma centers have the important task of navigating a patient through the complex process of obtaining services and tools for success. This summary from the American Association for the Surgery of Trauma Prevention Committee focuses on a model that has been present for several years, but has not been brought to full awareness in the trauma world. It highlights the importance of the Family Justice Center concept that brings a multitude of organizations under one roof, thus eliminating the hurdles encompassed by trauma patients, seeking life-changing resources necessary to mitigate the impact of both community violence exposure and intimate partner/domestic violence. It discusses the potential benefits of a partnership between trauma centers and Family Justice Centers and similar models. Finally, it also raises awareness of important programmatic evaluation research required in the arena of injury prevention targeting a population whose outcomes are difficult to measure.

COVID-19 in trauma: a propensity-matched analysis of COVID and non-COVID trauma patients.

PURPOSE: There is mounting evidence that surgical patients with COVID-19 have higher morbidity and mortality than patients without COVID-19. Infection is prevalent amongst the trauma population, but any effect of COVID-19 on trauma patients is unknown. We aimed to evaluate the effect of COVID-19 on a trauma population, hypothesizing increased mortality and pulmonary complications for COVID-19-positive (COVID) trauma patients compared to propensity-matched COVID-19-negative (non-COVID) patients. METHODS: A retrospective analysis of trauma patients presenting to 11 Level-I and II trauma centers in California between 1/1/2019-6/30/2019 and 1/1/2020-6/30/2020 was performed. A 1:2 propensity score model was used to match COVID to non-COVID trauma patients using age, blunt/penetrating mechanism, injury severity score, Glasgow Coma Scale score, systolic blood pressure, respiratory rate, and heart rate. Outcomes were compared between the two groups. RESULTS: A total of 20,448 trauma patients were identified during the study period. 53 COVID trauma patients were matched with 106 non-COVID trauma patients. COVID patients had higher rates of mortality (9.4% vs 1.9%, p = 0.029) and pneumonia (7.5% vs. 0.0%, p = 0.011), as well as a longer mean length of stay (LOS) (7.47 vs 3.28 days, p < 0.001) and intensive care unit LOS (1.40 vs 0.80 days, p = 0.008), compared to non-COVID patients. CONCLUSION: This multicenter retrospective study found increased rates of mortality and pneumonia, as well as a longer LOS, for COVID trauma patients compared to a propensity-matched cohort of non-COVID patients. Further studies are warranted to validate these findings and to elucidate the underlying pathways responsible for higher mortality in COVID trauma patients.

Kinetics of the multitasking high-affinity Win binding site of WDR5 in restricted and unrestricted conditions.

Recent advances in quantitative proteomics show that WD40 proteins play a pivotal role in numerous cellular networks. Yet, they have been fairly unexplored and their physical associations with other proteins are ambiguous. A quantitative understanding of these interactions has wide-ranging significance. WD40 repeat protein 5 (WDR5) interacts with all members of human SET1/MLL methyltransferases, which regulate methylation of the histone 3 lysine 4 (H3K4). Here, using real-time binding measurements in a high-throughput setting, we identified the kinetic fingerprint of transient associations between WDR5 and 14-residue WDR5 interaction (Win) motif peptides of each SET1 protein (SET1Win). Our results reveal that the high-affinity WDR5-SET1Win interactions feature slow association kinetics. This finding is likely due to the requirement of SET1Win to insert into the narrow WDR5 cavity, also named the Win binding site. Furthermore, our explorations indicate fairly slow dissociation kinetics. This conclusion is in accordance with the primary role of WDR5 in maintaining the functional integrity of a large multisubunit complex, which regulates the histone methylation. Because the Win binding site is considered a key therapeutic target, the immediate outcomes of this study could form the basis for accelerated developments in medical biotechnology.

The coronavirus disease 2019 (COVID-19) stay-at-home order's unequal effects on trauma volume by insurance status in Southern California.

BACKGROUND: The rapid spread of coronavirus disease 2019 in the United States led to a variety of mandates intended to decrease population movement and "flatten the curve." However, there is evidence some are not able to stay-at-home due to certain disadvantages, thus remaining exposed to both coronavirus disease 2019 and trauma. We therefore sought to identify any unequal effects of the California stay-at-home orders between races and insurance statuses in a multicenter study utilizing trauma volume data. METHODS: A posthoc multicenter retrospective analysis of trauma patients presenting to 11 centers in Southern California between the dates of January 1, 2020, and June 30, 2020, and January 1, 2019, and June 30, 2019, was performed. The number of trauma patients of each race/insurance status was tabulated per day. We then calculated the changes in trauma volume related to stay-at-home orders for each race/insurance status and compared the magnitude of these changes using statistical resampling. RESULTS: Compared to baseline, there was a 40.1% drop in total trauma volume, which occurred 20 days after stay-at-home orders. During stay-at-home orders, the average daily trauma volume of patients with Medicaid increased by 13.7 ± 5.3%, whereas the volume of those with Medicare, private insurance, and no insurance decreased. The average daily trauma volume decreased for White, Black, Asian, and Latino patients with the volume of Black and Latino patients dropping to a similar degree compared to White patients. CONCLUSION: This retrospective multicenter study demonstrated that patients with Medicaid had a paradoxical increase in trauma volume during stay-at-home orders, suggesting that the most impoverished groups remain disproportionately exposed to trauma during a pandemic, further exacerbating existing health disparities.

Prevention of Firearm Violence Through Specific Types of Community-based Programming: An Eastern Association for the Surgery of Trauma Evidence-based Review.

OBJECTIVE: The purpose of this review was to provide an evidence-based recommendation for community-based programs to mitigate gun violence, from the Eastern Association for the Surgery of Trauma (EAST). SUMMARY BACKGROUND DATA: Firearm Injury leads to >40,000 annual deaths and >115,000 injuries annually in the United States. Communities have adopted culturally relevant strategies to mitigate gun related injury and death. Two such strategies are gun buyback programs and community-based violence prevention programs. METHODS: The Injury Control and Violence Prevention Committee of EAST developed Population, Intervention, Comparator, Outcomes (PICO) questions and performed a comprehensive literature and gray web literature search. Using GRADE methodology, they reviewed and graded the literature and provided consensus recommendations informed by the literature. RESULTS: A total of 19 studies were included for analysis of gun buyback programs. Twenty-six studies were reviewed for analysis for community-based violence prevention programs. Gray literature was added to the discussion of PICO questions from selected websites. A conditional recommendation is made for the implementation of community-based gun buyback programs and a conditional recommendation for community-based violence prevention programs, with special emphasis on cultural appropriateness and community input. CONCLUSIONS: Gun violence may be mitigated by community-based efforts, such as gun buybacks or violence prevention programs. These programs come with caveats, notably community cultural relevance and proper support and funding from local leadership.Level of Evidence: Review, Decision, level III.

Changes in traumatic mechanisms of injury in Southern California related to COVID-19: Penetrating trauma as a second pandemic.

BACKGROUND: The COVID-19 pandemic resulted in a statewide stay-at-home (SAH) order in California beginning March 19, 2020, forcing large-scale behavioral changes and taking an emotional and economic toll. The effects of SAH orders on the trauma population remain unknown. We hypothesized an increase in rates of penetrating trauma, gunshot wounds, suicide attempts, and domestic violence in the Southern California trauma population after the SAH order. METHODS: A multicenter retrospective analysis of all trauma patients presenting to 11 American College of Surgeons levels I and II trauma centers spanning seven counties in California was performed. Demographic data, injury characteristics, clinical data, and outcomes were collected. Patients were divided into three groups based on injury date: before SAH from January 1, 2020, to March 18, 2020 (PRE), after SAH from March 19, 2020, to June 30, 2020 (POST), and a historical control from March 19, 2019, to June 30, 2019 (CONTROL). POST was compared with both PRE and CONTROL in two separate analyses. RESULTS: Across all periods, 20,448 trauma patients were identified (CONTROL, 7,707; PRE, 6,022; POST, 6,719). POST had a significantly increased rate of penetrating trauma (13.0% vs. 10.3%, p < 0.001 and 13.0% vs. 9.9%, p < 0.001) and gunshot wounds (4.5% vs. 2.4%, p = 0.002 and 4.5% vs. 3.7%, p = 0.025) compared with PRE and CONTROL, respectively. POST had a suicide attempt rate of 1.9% and a domestic violence rate of 0.7%, which were similar to PRE (p = 0.478, p = 0.514) and CONTROL (p = 0.160, p = 0.618). CONCLUSION: This multicenter Southern California study demonstrated an increased rate of penetrating trauma and gunshot wounds after the COVID-19 SAH orders but no difference in attempted suicide or domestic violence rates. These findings may provide useful information regarding resource utilization and a target for societal intervention during the current or future pandemic(s). LEVEL OF EVIDENCE: Epidemiological, level IV.

F-ATP-ase of Escherichia coli membranes: The ubiquitous MgADP-inhibited state and the inhibited state induced by the ε-subunit's C-terminal domain are mutually exclusive.

ATP synthases are important energy-coupling, rotary motor enzymes in all kingdoms of life. In all F-type ATP synthases, the central rotor of the catalytic F1 complex is composed of the γ subunit and the N-terminal domain (NTD) of the ε subunit. In the enzymes of diverse bacteria, the C-terminal domain of ε (εCTD) can undergo a dramatic conformational change to trap the enzyme in a transiently inactive state. This inhibitory mechanism is absent in the mitochondrial enzyme, so the εCTD could provide a means to selectively target ATP synthases of pathogenic bacteria for antibiotic development. For Escherichia coli and other bacterial model systems, it has been difficult to dissect the relationship between ε inhibition and a MgADP-inhibited state that is ubiquitous for FOF1 from bacteria and eukaryotes. A prior study with the isolated catalytic complex from E. coli, EcF1, showed that these two modes of inhibition are mutually exclusive, but it has long been known that interactions of F1 with the membrane-embedded FO complex modulate inhibition by the εCTD. Here, we study membranes containing EcFOF1 with wild-type ε, ε lacking the full εCTD, or ε with a small deletion at the C-terminus. By using compounds with distinct activating effects on F-ATP-ase activity, we confirm that εCTD inhibition and ubiquitous MgADP inhibition are mutually exclusive for membrane-bound E. coli F-ATP-ase. We determine that most of the enzyme complexes in wild-type membranes are in the ε-inhibited state (>50%) or in the MgADP-inhibited state (30%).