Targeting spectroscopic accuracy for dispersion bound systems from ab initio techniques: Translational eigenstates of Ne@C70.

We investigate the endofullerene system Ne@C70 by constructing a three-dimensional Potential Energy Surface (PES) describing the translational motion of the Ne atom. This is constructed from electronic structure calculations from a plethora of methods, including MP2, SCS-MP2, SOS-MP2, RPA@PBE, and C(HF)-RPA, which were previously used for He@C60 in Panchagnula et al. [J. Chem. Phys. 160, 104303 (2024)], alongside B86bPBE-25X-XDM and B86bPBE-50X-XDM. The reduction in symmetry moving from C60 to C70 introduces a double well potential along the anisotropic direction, which forms a test of the sensitivity and effectiveness of the electronic structure methods. The nuclear Hamiltonian is diagonalized using a symmetrized double minimum basis set outlined in Panchagnula and Thom [J. Chem. Phys. 159, 164308 (2023)], with translational energies having error bars ±1 and ±2 cm-1. We find no consistency between electronic structure methods as they find a range of barrier heights and minima positions of the double well and different translational eigenspectra, which also differ from the Lennard-Jones (LJ) PES given in Mandziuk and Bacic [J. Chem. Phys. 101, 2126-2140 (1994)]. We find that generating effective LJ parameters for each electronic structure method cannot reproduce the full PES nor recreate the eigenstates, and this suggests that the LJ form of the PES, while simple, may not be best suited to describe these systems. Even though MP2 and RPA@PBE performed best for He@C60, due to the lack of concordance between all electronic structure methods, we require more experimental data in order to properly validate the choice.

Association of oral contraceptives and tubal ligation with risk of early natural menopause.

STUDY QUESTION: What is the association of oral contraceptives (OCs) and tubal ligation (TL) with early natural menopause? SUMMARY ANSWER: We did not observe an association of OC use with risk of early natural menopause; however, TL was associated with a modestly higher risk. WHAT IS KNOWN ALREADY: OCs manipulate hormone levels, prevent ovulation, and may modify the rate of follicular atresia, while TL may disrupt the blood supply to the ovaries. These mechanisms may be associated with risk of early menopause, a condition associated with increased risk of cardiovascular disease and other adverse health outcomes. STUDY DESIGN, SIZE, DURATION: We examined the association of OC use and TL with natural menopause before the age of 45 years in a population-based study within the prospective Nurses' Health Study II (NHSII) cohort. Participants were followed from 1989 to 2017 and response rates were 85-90% for each cycle. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants included 106 633 NHSII members who were premenopausal and aged 25-42 years at baseline. Use, duration and type of OC, and TL were measured at baseline and every 2 years. Menopause status and age were assessed every 2 years. Follow-up continued until early menopause, age 45 years, hysterectomy, oophorectomy, death, cancer diagnosis, or loss to follow-up. We used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% CIs adjusted for lifestyle, dietary, and reproductive factors. MAIN RESULTS AND THE ROLE OF CHANCE: Over 1.6 million person-years, 2579 members of the analytic cohort experienced early natural menopause. In multivariable models, the duration, timing, and type of OC use were not associated with risk of early menopause. For example, compared with women who never used OCs, those reporting 120+ months of OC use had an HR for early menopause of 1.01 (95% CI, 0.87-1.17; P for trend=0.71). TL was associated with increased risk of early menopause (HR = 1.17, 95% CI, 1.06-1.28). LIMITATIONS, REASONS FOR CAUTION: Our study population is homogenous with respect to race and ethnicity. Additional evaluation of these relations in more diverse populations is important. WIDER IMPLICATIONS OF THE FINDINGS: To our knowledge, this is the largest study examining the association of OC use and TL with early natural menopause to date. While TL was associated with a modest higher risk of early menopause, our findings do not support any material hazard or benefit for the use of OCs. STUDY FUNDING/COMPETING INTEREST(S): The study was sponsored by UO1CA176726 and R01HD078517 from the National Institutes of Health and Department of Health and Human Services. The work was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The authors have no competing interests to report. TRIAL REGISTRATION NUMBER: N/A.

Adult adiposity and risk of early menopause.

STUDY QUESTION: Is adult adiposity associated with early menopause? SUMMARY ANSWER: Overall and abdominal adiposity were non-linearly associated with odds for early natural menopause with elevated odds observed among women who were underweight in early or mid-adulthood compared to lean-normal weight women. WHAT IS KNOWN ALREADY: High and low adiposity have been associated with reproductive function and may potentially impact timing of menopause. It is unclear whether various aspects of adiposity are associated with risk of early menopause. STUDY DESIGN, SIZE, DURATION: Prospective cohort study that examined data from 78 759 premenopausal women from the Nurses' Health Study II who were followed from 1989 to 2011 for incidence of early natural menopause. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were aged 25-42 years and premenopausal at baseline in 1989, when information on menopausal status, height and weight was reported via questionnaire. Information on menopausal status, type of menopause (natural, surgical, radiation/chemotherapy), hormone therapy use and weight was updated every two years along with information on smoking, physical activity and other behavioral and health-related factors. Multivariable logistic regression was used to estimate odds ratios for early menopause, defined as natural menopause before age 45 years, by aspects of adiposity. MAIN RESULTS AND THE ROLE OF CHANCE: Early natural menopause was reported by 2804 participants. Body mass index (BMI) was non-linearly associated with risk for early menopause. Compared to women with BMI = 18.5-22.4 kg/m2, those with BMI < 18.5 kg/m2 had a significant 30% higher odds of early menopause (95% confidence interval (CI) = 1.08, 1.57), while women with BMIs between 25.0-29.9 kg/m2 had significant 21-30% lower odds. Odds were not higher in women with BMI ≥ 35.0 kg/m2 in fully adjusted analysis. Non-linear associations with higher odds in underweight women were also observed for age 18 and age 35 BMI, though lower odds for overweight women was only observed for age 35 BMI. Odds were highest among women with age 18 BMI < 18.5 kg/m2 reporting severe weight cycling. LIMITATIONS, REASONS FOR CAUTION: Though weight and early menopause status were self-reported, validation studies conducted among Nurses' Health Study participants suggest that self-reported weight is highly correlated with directly measured weight, and prospective self-reported menopausal status is highly reproducible. It is possible that underweight women may have been misclassified with an earlier age at menopause if being underweight led to amenorrhea. WIDER IMPLICATIONS OF THE FINDINGS: In one of the few studies to prospectively examine a variety of adiposity measures and risk for early menopause, our findings that women who were underweight in early or mid-adulthood had elevated risk for early menopause can assist in efforts to better understand the etiology of early menopause. Additional prospective research is needed to understand how low adiposity may physiologically impact timing of menopause. STUDY FUNDING/COMPETING INTEREST(S): This study was conducted with funding from NIH UM1CA176726 and R01HD078517. The authors declare no conflicts of interest. TRIAL REGISTRATION NUMBER: Not applicable.

Seasonality of suicide behavior in Northwest Alaska: 1990-2009.

OBJECTIVES: Suicide is a leading cause of death worldwide, and disproportionately affects Indigenous populations. Seasonal suicide patterns are variable in the literature, and could offer novel approaches to the timing and focus of prevention efforts if better understood. With a suicide surveillance system in place since 1989, this study offers an unprecedented opportunity to explore seasonal variations in both fatal and non-fatal suicide behavior in an Indigenous Arctic region. STUDY DESIGN: Cross-sectional. METHODS: In this descriptive study, we analyzed data collected from 1990 to 2009 in the rural northwest region of Alaska, both graphically and using the chi-squared test for multinomials. RESULTS: We found a significant monthly variation for suicide attempts, with a peak in suicide behavior observed between April and August (P = 0.0002). Monthly variation was more pronounced among individuals ≤29 years of age, and was present in both males and females, although the seasonal pattern differed by sex. CONCLUSIONS: Our findings of a significant seasonal pattern in suicide behavior, with monthly variation (summer peak) in non-fatal suicide behavior among younger age groups, and among both males and females can assist planners in targeting subpopulations for prevention at different times of the year.

Modulational instability of co-propagating internal wavetrains under rotation.

Weakly-nonlinear unidirectional long internal waves in a non-rotating frame are well described by the Korteweg-de Vries equation (KdV). Within the KdV framework, all isolated monochromatic wavetrains are stable to modulational instability. However, analysis of a coupled nonlinear Schrödinger equation system (CNLS) has shown that all systems of two co-propagating monochromatic wavetrains in the KdV are modulationally unstable. To take into account the effect of the background rotation of the Earth on long internal waves, this analysis is extended here to derive the CNLS for the rotation-modified KdV, or Ostrovsky, equation. Rotation stabilises wavetrain pairs when the wavelengths of both waves comprising the wavetrains are longer than the linear wave with maximum group velocity. The particular case when the wavetrains have different wavenumbers but the same linear group speed is emphasised.

Association of inflammation markers with menstrual symptom severity and premenstrual syndrome in young women.

STUDY QUESTION: Are markers of chronic inflammation associated with menstrual symptom severity and premenstrual syndrome (PMS)? SUMMARY ANSWER: Serum levels of inflammatory markers, including interleukin (IL)-2, IL-4, IL-10, IL-12 and interferon (IFN)-γ were positively associated with menstrual symptom severity and/or PMS in young women. WHAT IS KNOWN ALREADY: Chronic inflammation has been implicated in the etiology of depression and other disorders that share common features with PMS, but whether inflammation contributes to menstrual symptom severity and PMS is unknown. STUDY DESIGN, SIZE, DURATION: Cross-sectional study of 277 women aged 18-30 years, conducted in 2006-2011. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants provided information on menstrual symptoms, lifestyle, diet, anthropometry and other factors by questionnaire and/or direct measurement, and a mid-luteal phase fasting blood sample was taken between 7 a.m. and 12 p.m. Total, physical and affective menstrual symptom scores were calculated for all participants, of whom 13% (n = 37) met criteria for moderate-to-severe PMS and 24% (n = 67) met PMS control criteria. Inflammatory factors assayed in serum included IL-1ß, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p70, IL-13, tumor necrosis factor-α, granulocyte macrophage colony stimulating factor, IFN-γ and C-reactive protein. MAIN RESULTS AND THE ROLE OF CHANCE: After adjustment for age, smoking status and BMI, total menstrual symptom score was positively associated with levels of IL-2 (percentage difference in women at the 75th percentile of total symptom score versus at the 25th percentile = 24.7%; P = 0.04), IL-4 (21.5%; P = 0.04), IL-10 (28.0%; P < 0.01) and IL-12 (42.0%; P = 0.02) in analyses including all participants. Affective menstrual symptom score was linearly related to levels of IL-2 (percentage difference at 75th percentile versus 25th percentile = 31.0%; P = 0.02), while physical/behavioral symptom score was linearly related to levels of IL-4 (19.1%; P = 0.03) and IL-12 (33.2%; P = 0.03). Additionally, mean levels of several factors were significantly higher in women meeting PMS criteria compared with women meeting control criteria, including IL-4 (92% higher in cases versus controls; P = 0.01); IL-10 (87%; P = 0.03); IL-12 (170%; P = 0.04) and IFN-γ (158%; P = 0.01). LIMITATIONS, REASONS FOR CAUTION: Our study has several limitations. While a single blood sample may not perfectly capture long-term levels of inflammation, ample data suggest that levels of cytokines are stable over time. Although we did not base our assessment of PMS on prospective symptom diaries, we used validated criteria to define PMS cases and controls, and excluded women with evidence of comorbid mood disorders. Furthermore, because of the cross-sectional design of the study, the temporal relation of inflammatory factors and menstrual symptoms is unclear. WIDER IMPLICATIONS OF THE FINDINGS: To our knowledge, this is among the first studies to suggest that inflammatory factors may be elevated in women experiencing menstrual symptoms and PMS. Additional studies are needed to determine whether inflammation plays an etiologic role in PMS. STUDY FUNDING/COMPETING INTERESTS: This study was funded by the Departments of Public Health and Nutrition and by a Faculty Research Grant, University of Massachusetts Amherst. No conflicts declared. TRIAL REGISTRATION NUMBER: N/A.

Are existing measures of overall diet quality associated with peak bone mass in young premenopausal women?

BACKGROUND: Low peak bone mass in young adulthood is associated with an increased risk of osteoporosis and fracture after menopause, and an understanding of the modifiable factors that contribute to low peak bone mass is important for fracture prevention. Diet is an important modifiable factor linked to bone health and, although studies have examined the role of individual dietary components in bone health, bone growth and maintenance are complex processes, and such studies may not adequately represent the role of diet in these processes. METHODS: To address this issue, a cross-sectional analysis of 226 healthy, premenopausal women aged 18-30 years was conducted to determine whether existing indices of overall diet quality are associated with bone density in premenopausal women nearing peak bone mass. Bone density was measured using dual-energy X-ray absorptiometry and diet quality was measured using two overall diet scores based on current dietary guidelines: the Recommended Food Score and the Alternate Healthy Eating Index (AHEI). RESULTS: In the multiple linear regression, bone density did not increase across quartiles of either diet quality score and was not associated with continuous diet quality variables. Furthermore, none of the individual AHEI components (e.g. fruit intake, vegetable intake) were associated with bone density. CONCLUSIONS: These findings suggest that existing diet quality scores are not appropriate for studies of peak bone mass, most likely because they do not give sufficient weight to foods and nutrients important to bone health. We recommend the development of a diet pattern index that better predicts bone mass measures.

Small molecule binding to surface-supported single-site transition-metal reaction centres.

Despite dominating industrial processes, heterogeneous catalysts remain challenging to characterize and control. This is largely attributable to the diversity of potentially active sites at the catalyst-reactant interface and the complex behaviour that can arise from interactions between active sites. Surface-supported, single-site molecular catalysts aim to bring together benefits of both heterogeneous and homogeneous catalysts, offering easy separability while exploiting molecular design of reactivity, though the presence of a surface is likely to influence reaction mechanisms. Here, we use metal-organic coordination to build reactive Fe-terpyridine sites on the Ag(111) surface and study their activity towards CO and C2H4 gaseous reactants using low-temperature ultrahigh-vacuum scanning tunnelling microscopy, scanning tunnelling spectroscopy, and atomic force microscopy supported by density-functional theory models. Using a site-by-site approach at low temperature to visualize the reaction pathway, we find that reactants bond to the Fe-tpy active sites via surface-bound intermediates, and investigate the role of the substrate in understanding and designing single-site catalysts on metallic supports.

Wave packets in the anomalous Ostrovsky equation.

The anomalous Ostrovsky equation, which describes waves in vertically sheared ocean flows and magnetoacoustic waves, possesses steadily propagating, finite-amplitude, localized wave-packet solutions. It is shown here that these solutions can be obtained asymptotically, using Whitham modulation theory, as the solution to a nonlinear eigenvalue problem. This allows the various wave-packet solutions to be delineated and compared to solutions of the full equations of motion. A periodic solution with an embedded wave train is also constructed.

Structure and formation of highly luminescent protein-stabilized gold clusters.

Highly luminescent gold clusters simultaneously synthesized and stabilized by protein molecules represent a remarkable category of nanoscale materials with promising applications in bionanotechnology as sensors. Nevertheless, the atomic structure and luminescence mechanism of these gold clusters are still unknown after several years of developments. Herein, we report findings on the structure, luminescence and biomolecular self-assembly of gold clusters stabilized by the large globular protein, bovine serum albumin. We highlight the surprising identification of interlocked gold-thiolate rings as the main gold structural unit. Importantly, such gold clusters are in a rigidified state within the protein scaffold, offering an explanation for their highly luminescent character. Combined free-standing cluster synthesis (without protecting protein scaffold) with rigidifying and un-rigidifying experiments, were designed to further verify the luminescence mechanism and gold atomic structure within the protein. Finally, the biomolecular self-assembly process of the protein-stabilized gold clusters was elucidated by time-dependent X-ray absorption spectroscopy measurements and density functional theory calculations.

Whitham modulation theory for the Ostrovsky equation.

This paper derives the Whitham modulation equations for the Ostrovsky equation. The equations are then used to analyse localized cnoidal wavepacket solutions of the Ostrovsky equation in the weak rotation limit. The analysis is split into two main parameter regimes: the Ostrovsky equation with normal dispersion relevant to typical oceanic parameters and the Ostrovsky equation with anomalous dispersion relevant to strongly sheared oceanic flows and other physical systems. For anomalous dispersion a new steady, symmetric cnoidal wavepacket solution is presented. The new wavepacket can be represented as a solution of the modulation equations and an analytical solution for the outer solution of the wavepacket is given. For normal dispersion the modulation equations are used to describe the unsteady finite-amplitude wavepacket solutions produced from the rotation-induced decay of a Korteweg-de Vries solitary wave. Again, an analytical solution for the outer solution can be given. The centre of the wavepacket closely approximates a train of solitary waves with the results suggesting that the unsteady wavepacket is a localized, modulated cnoidal wavetrain. The formation of wavepackets from solitary wave initial conditions is considered, contrasting the rapid formation of the packets in anomalous dispersion with the slower formation of unsteady packets under normal dispersion.

Economic analysis of adjuvant interferon alfa-2b in high-risk melanoma based on projections from Eastern Cooperative Oncology Group 1684.

PURPOSE: Interferon alfa-2b (IFN) in a randomized clinical trial (E1684) prolonged relapse-free and total survival in high-risk resected melanoma. However, the costs and toxicities of IFN are barriers to its widespread use. This study was undertaken to analyze the projected costs and long-term benefits of IFN by combining prospectively collected data on IFN actual dosage, time of recurrence, and survival with secondary data on long-term melanoma recurrence risks to project the cost-effectiveness of adjuvant IFN compared with observation. PATIENTS AND METHODS: Two hypothetical cohorts of 50-year-old melanoma patients whose mean IFN dosage and clinical results were directly taken from E1684 were included in the study. Melanoma recurrence risks beyond 5 years were derived from international databases. Melanoma recurrence care costs and quality-of-life adjustments, when considered, were based on expert consensus. End points were incremental costs, life-years gained, and cost per life-year gained with and without quality-of-life adjustments. RESULTS: The IFN cohort was projected to have an increased (undiscounted) survival of 0.52 years at 7 years and 1.90 years over a lifetime. The projected incremental cost (in 1996 United States dollars) per life-year gained in the IFN cohort ranged from $13,700 after 35 years to $32,600 at 7 years, the median follow-up of E1684. Using assigned quality-of-life values for IFN and recurrence, the lifetime cost per quality adjusted life-year increased to $15,200. Even if treatment costs for recurrence were excluded, the lifetime incremental cost per life-year gained was $21,600. CONCLUSION: The cost and toxicity of IFN must be balanced against its projected benefits in high-risk melanoma. The derived cost-effectiveness and cost-utility ratios for IFN were comparable to other cancer interventions for which cost-effectiveness analysis has been performed.

Wave-packet formation at the zero-dispersion point in the Gardner-Ostrovsky equation.

The long-time effect of weak rotation on an internal solitary wave is the decay into inertia-gravity waves and the eventual emergence of a coherent, steadily propagating, nonlinear wave packet. There is currently no entirely satisfactory explanation as to why these wave packets form. Here the initial value problem is considered within the context of the Gardner-Ostrovsky, or rotation-modified extended Korteweg-de Vries, equation. The linear Gardner-Ostrovsky equation has maximum group velocity at a critical wave number, often called the zero-dispersion point. It is found here that a nonlinear splitting of the wave-number spectrum at the zero-dispersion point, where energy is shifted into the modulationally unstable regime of the Gardner-Ostrovsky equation, is responsible for the wave-packet formation. Numerical comparisons of the decay of a solitary wave in the Gardner-Ostrovsky equation and a derived nonlinear Schrödinger equation at the zero-dispersion point are used to confirm the spectral splitting.

Potential economic impact of glycoprotein IIb-IIIa inhibitors in improving outcomes of patients with acute ischemic coronary syndromes.

Despite the institution of various cost control measures in the 1980s, healthcare costs have continued to rise. Following the adoption of the Medicare prospective payment system, the Health Care Financing Administration (HFCA) recognized the need to assess medical effectiveness as well as the cost of care. Coronary artery bypass graft (CABG) and percutaneous transluminal coronary angioplasty (PTCA) procedures have been reported as the primary cost drivers in hospitalized patients with unstable angina, a form of acute ischemic coronary syndromes. Evaluation of glycoprotein IIb-IIIa inhibitors as primary therapy for these patients suggests that good value for money is possible, especially if the use of these agents results in a reduction in revascularization procedures.

Cefazolin for hysterectomy prophylaxis.

Efficacy data for single-dose cefazolin prophylaxis at hysterectomy are meager, and there are none evaluating the impact of route of administration on efficacy. For these reasons, 772 women undergoing elective abdominal or vaginal hysterectomy for benign diseases were given 1 g cefazolin either intramuscularly or intravenously in a randomized clinical trial. Preoperative diagnoses and clinical, surgical, and outcome variables were similar by route of administration for each surgical approach. Risk factors for infection after abdominal hysterectomy included younger age, lower postoperative hemoglobin concentration, and pelvic hematoma; women who developed infection after vaginal hysterectomy were heavier than those who remained uninfected and were more likely to have a pelvic hematoma. The overall incidence of major operative site infection requiring parenteral antimicrobial therapy in evaluable women was 7.2%: 7.6% for 539 women undergoing abdominal hysterectomy and 6.3% for 207 women undergoing vaginal hysterectomy. Postoperative infection was unrelated to route of cefazolin administration.

Cefoperazone and cefoxitin prophylaxis for abdominal hysterectomy.

One hundred one women undergoing elective abdominal hysterectomy were given perioperative cefoperazone or cefoxitin in a prospective randomized blinded study. Both regimens were well tolerated and no significant toxic or allergic manifestations were observed. Interrelationships between antimicrobial concentration in serum and pelvic tissues, intraoperative cardinal ligament cultures, febrile morbidity, and major postoperative infection were determined. At uterine removal, mean cefoperazone concentrations in serum (56.1 micrograms/mL) and pelvic tissues (18.6 micrograms/g) were significantly higher than mean concentrations of cefoxitin, ie, 16.1 micrograms/mL and 8.1 micrograms/g, respectively (P less than .001). The incidence of major postoperative infection was 6% or less with both regimens. Perioperative prophylaxis significantly reduced the incidence of this infection. When it did develop, however, it continued to cause significant morbidity, prolonging hospital stay a mean of more than four days (P less than .001) and increasing the hospital bill a mean of almost $1500 (P less than .001).

Reexploration for hemorrhage following coronary artery bypass grafting: incidence and risk factors. Northern New England Cardiovascular Disease Study Group.

OBJECTIVE: To assess mortality and risk factors associated with reexploration for hemorrhage in patients undergoing coronary artery bypass grafting (CABG). DESIGN: Regional cohort study. Patient characteristics, treatment variables, and outcome measures were collected prospectively. SETTING: All 5 centers performing cardiac surgery in Maine, New Hampshire, and Vermont. PATIENTS: A consecutive cohort of 8586 patients undergoing isolated CABG between 1992 and 1995. MAIN OUTCOME MEASURES: Postoperative hemorrhage leading to reexploration, in-hospital mortality, and length of stay. RESULTS: A total of 305 patients (3.6%) underwent reexploration for bleeding. In these patients, in-hospital mortality was nearly 3 times higher (9.5% vs 3.3% for patients not requiring reoperation, P<.001) and average length of stay from surgery to discharge was significantly longer (14.5 days vs 8.6 days, P<.001). High rates of reexploration for hemorrhage were observed in patients with prolonged (> 150 minutes) cardiopulmonary bypass (39 [11.1%] of 351) and in those requiring an intra-aortic balloon pump intraoperatively (12 [8%] of 139). In multivariate analysis, older age, smaller body surface area, prolonged cardiopulmonary bypass, and number of distal anastomoses were associated with increased bleeding risks. The use of thrombolytic therapy within 48 hours of surgery was weakly but not significantly associated with the need for reexploration. Factors not significantly associated with reexploration included patient sex, preoperative ejection fraction, surgical priority, history of liver disease, myocardial infarction, prior CABG, renal failure, and diabetes mellitus. CONCLUSIONS: Hemorrhage requiring reexploration after CABG is associated with markedly increased mortality and length of stay. Patients predicted to have increased risks of bleeding may benefit from prophylactic use of aprotinin, aminocaproic acid, or other agents shown to reduce hemorrhage.

Primary leiomyosarcoma of the thoracic aorta presenting as a contained rupture.

Primary neoplasms of the aorta are rare and usually present with signs and symptoms due to intraluminal obstruction. A case of a 48-year-old man who presented with a contained rupture of the thoracic aorta secondary to a leiomyosarcoma is reported.

Effect of preoperative aspirin use on mortality in coronary artery bypass grafting patients.

BACKGROUND: Discontinuing aspirin use in patients before coronary artery bypass grafting (CABG) has focused on bleeding risks. The effect of aspirin use on overall mortality with this procedure has not been studied. METHODS: We performed a case patient-control patient study of the 8,641 consecutive isolated CABG procedures performed between July 1987 and May 1991 in Maine, New Hampshire, and Vermont. Patients included all 368 deaths. Each case patient was paired with approximately two matched survivors (control patients). Aspirin use was defined by identification of ingestion within 7 days before the operation. RESULTS: CABG patients using preoperative aspirin were less likely to experience in-hospital mortality in univariate (odds ratio [OR] = 0.73, 95% confidence interval [0.54, 0.97]) and multivariate [OR = 0.55, (0.31, 0.98)] analysis compared to nonusers. No significant difference was seen in the amount of chest tube drainage, transfusion of blood products, or need for reexploration for hemorrhage between patients who did and did not receive aspirin. CONCLUSIONS: Preoperative aspirin use appears to be associated with a decreased risk of mortality in CABG patients without significant increase in hemorrhage, blood product requirements, or related morbidities.

Trends in rates of reexploration for hemorrhage after coronary artery bypass surgery. Northern New England Cardiovascular Disease Study Group.

BACKGROUND: While mortality rates associated with coronary artery bypass grafting (CABG) have been declining, it is unknown whether similar improvements in the rates of morbidity have been occurring. This study examines trends in reexploration rates for hemorrhage, one of the serious complications of CABG surgery. It also explores changes in patient characteristics and several surgeon practice patterns potentially related to bleeding risks that may explain variations in these rates. METHODS: We performed a regional observational study of all of the 12,555 consecutive patients undergoing isolated CABG surgery in northern New England between 1992 and 1997. The rates of reexploration and patient characteristics were examined between two time intervals: period I (January 1, 1992 to June 1, 1994) and period II (June 1, 1995 to March 31, 1997). All of the region's 23 practicing surgeons responsible for these patients were surveyed to assess changes in practice patterns potentially related to bleeding risks. RESULTS: The adjusted rates of reexploration for bleeding declined 46% between periods I and II (3.6% versus 2.0%, p < 0.001). All of the five cardiac centers in northern New England showed similar trends with adjusted risk reductions ranging from 32% to 48% between the two time periods. This decline occurred despite the patients in period II having higher percentages of risk factors for reexploration for bleeding compared to patients in period I. From the surgeon survey, the number of surgeons using antifibrinolytics markedly increased from period I to period II. More surgeons were also using preoperative aspirin and heparin up until the time of surgery in period II. CONCLUSIONS: Similar to the rates of mortality, the rates of reexploration for bleeding following CABG surgery are substantially declining. This decrease in the reexploration rates occurred despite higher patient risks.