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1.
Surg Endosc ; 37(8): 6495-6503, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37264227

RESUMEN

BACKGROUND: Patients who undergo vertical sleeve gastrectomy (VSG) are at risk of postoperative GERD. The reasons are multifactorial, but half of conversions to Roux-en Y gastric bypass are for intractable GERD. Our institution routinely performs preoperative pH and high-resolution manometry studies to aid in operative decision making. We hypothesize that abnormal pH studies in concert with ineffective esophageal motility would lead to higher rates of postoperative reflux after VSG. METHODS: A single institution retrospective review was conducted of adult patients who underwent preoperative pH and manometry testing and VSG between 2015 and 2021. Patients filled out a symptom questionnaire at the time of testing. Postoperative reflux was defined by patient-reported symptoms at 1-year follow-up. Univariate logistic regression was used to examine the relationship between esophageal tests and postoperative reflux. The Lui method was used to determine the cutpoint for pH and manometric variables maximizing sensitivity and specificity for postoperative reflux. RESULTS: Of 291 patients who underwent VSG, 66 (22.7%) had a named motility disorder and 67 (23%) had an abnormal DeMeester score. Preoperatively, reflux was reported by 122 patients (41.9%), of those, 69 (56.6%) had resolution. Preoperative pH and manometric abnormalities, and BMI reduction did not predict postoperative reflux status (p = ns). In a subgroup analysis of patients with an abnormal preoperative pH study, the Lui cutpoint to predict postoperative reflux was a DeMeester greater than 24.8. Postoperative reflux symptoms rates above and below this point were 41.9% versus 17.1%, respectively (p = 0.03). CONCLUSION: While manometry abnormalities did not predict postoperative reflux symptoms, GERD burden did. Patients with a mildly elevated DeMeester score had a low risk of postoperative reflux compared to patients with a more abnormal DeMeester score. A preoperative pH study may help guide operative decision-making and lead to better counseling of patients of their risk for reflux after VSG.


Asunto(s)
Derivación Gástrica , Reflujo Gastroesofágico , Laparoscopía , Obesidad Mórbida , Adulto , Humanos , Obesidad Mórbida/complicaciones , Obesidad Mórbida/cirugía , Reflujo Gastroesofágico/diagnóstico , Reflujo Gastroesofágico/etiología , Reflujo Gastroesofágico/cirugía , Manometría , Gastrectomía/efectos adversos , Gastrectomía/métodos , Estudios Retrospectivos , Laparoscopía/métodos
2.
Surg Endosc ; 36(2): 1627-1632, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34076763

RESUMEN

BACKGROUND: The use of biologic mesh in paraesophageal hernia repair (PEHR) has been associated with decreased short-term recurrence but no statistically significant difference in long-term recurrence. Because of this, we transitioned from routine to selective use of mesh for PEHR. The aim of this study was to examine our indications for selective mesh use and to evaluate patient outcomes in this population. METHODS: We queried a prospectively maintained database for patients who underwent laparoscopic PEHR with biologic mesh from October 2015 to October 2018, then performed a retrospective chart review. The decision to use mesh was made intraoperatively by the surgeon. Recurrence was defined as the presence of > 2 cm intrathoracic stomach on postoperative upper gastrointestinal (UGI) series. RESULTS: Mesh was used in 61/169 (36%) of first-time PEHRs, and in 47/82 (57%) of redo PEHRs. Among first-time PEHRs, the indications for mesh included hiatal tension (85%), poor crural tissue quality (11%), or both (5%). Radiographic recurrence occurred in 15% of first-time patients (symptomatic N = 2, asymptomatic N = 3). There were no reoperations for recurrence. Among redo PEHRs, the indication for mesh was most commonly the redo nature of the repair itself (55%), but also hiatal tension (51%), poor crural tissue quality (13%), or both (4%). Radiographic recurrence occurred in 21% of patients (symptomatic N = 4, asymptomatic N = 1). There was 1 reoperation for recurrence in the redo-repair group. CONCLUSIONS: We selectively use biologic mesh in a third of our first-time repair patients and in over half of our redo-repair patients when there is a perceived high risk of recurrence based on hiatal tension, poor tissue quality, or prior recurrence. Despite the high risk for radiologic recurrence, there was only 1 reoperation for recurrence in the entire cohort.


Asunto(s)
Productos Biológicos , Hernia Hiatal , Laparoscopía , Hernia Hiatal/etiología , Hernia Hiatal/cirugía , Herniorrafia/efectos adversos , Humanos , Recurrencia , Estudios Retrospectivos , Mallas Quirúrgicas , Resultado del Tratamiento
3.
Surg Endosc ; 35(10): 5531-5537, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-33025253

RESUMEN

INTRODUCTION: Venous thromboembolism (VTE) is a significant cause of morbidity and mortality after bariatric surgery. Roughly 80% of VTEs occur post-discharge. The frequency of post-discharge heparin (PDH) prophylaxis use is unknown, and evidence about benefits and risks is limited. We aimed to determine the rate of use of PDH prophylaxis and evaluate its relationship with VTE and bleeding events. METHODS: Using the Truven Health MarketScan® database, we performed a retrospective cohort study (2007-2015) of adult patients who underwent sleeve gastrectomy or gastric bypass. We determined PDH prophylaxis from outpatient pharmacy claims, and post-discharge 90-day VTE and bleeding events from outpatient and inpatient claims. We used propensity score-adjusted regression models to mitigate confounding bias. RESULTS: Among 43,493 patients (median age 45 years; 78% women; 77% laparoscopic gastric bypass, 17% laparoscopic sleeve gastrectomy, 6% open gastric bypass), 6% received PDH prophylaxis. Overall, 224 patients (0.52%) experienced VTEs, and 806 patients (1.85%) experienced bleeding. The unadjusted VTE rate did not differ between patients who did and did not receive PDH prophylaxis (0.39% vs. 0.52%, respectively; p = 0.347). The unadjusted bleeding rate was higher for the PDH prophylaxis group (2.74% vs. 1.80%, p < 0.001). In our adjusted analysis, a 23% lower risk of VTE in the PDH prophylaxis group was not statistically significant (odds ratio [OR] 0.77, 95% confidence interval [CI] 0.41 to 1.46), whereas the 47% higher risk of bleeding was statistically significant (OR 1.47, 95% CI 1.14 to 1.88). CONCLUSIONS: PDH prophylaxis after bariatric surgery is uncommon. In our analysis, use was not associated with a lower VTE risk but was associated with a higher bleeding risk.


Asunto(s)
Cirugía Bariátrica , Tromboembolia Venosa , Adulto , Cuidados Posteriores , Anticoagulantes/efectos adversos , Cirugía Bariátrica/efectos adversos , Femenino , Heparina/efectos adversos , Humanos , Masculino , Persona de Mediana Edad , Alta del Paciente , Estudios Retrospectivos , Tromboembolia Venosa/epidemiología , Tromboembolia Venosa/etiología , Tromboembolia Venosa/prevención & control
4.
Proc Natl Acad Sci U S A ; 109(32): 12894-8, 2012 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-22837402

RESUMEN

Inelastic neutron scattering, far-infrared spectroscopy, and cryogenic nuclear magnetic resonance are used to investigate the quantized rotation and ortho-para conversion of single water molecules trapped inside closed fullerene cages. The existence of metastable ortho-water molecules is demonstrated, and the interconversion of ortho-and para-water spin isomers is tracked in real time. Our investigation reveals that the ground state of encapsulated ortho water has a lifted degeneracy, associated with symmetry-breaking of the water environment.


Asunto(s)
Fulerenos/química , Espectroscopía de Resonancia Magnética/métodos , Modelos Moleculares , Teoría Cuántica , Rotación , Agua/química , Isomerismo , Espectrofotometría Infrarroja
5.
Surg Endosc ; 28(3): 816-20, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24337189

RESUMEN

BACKGROUND: The role of adrenalectomy in management of isolated metastatic adrenal tumors is increasingly established. Laparoscopy is becoming the preferred approach for these resections. We evaluated surgical and oncological outcomes of patients who underwent laparoscopic versus open adrenal metastasectomy and assessed the effect of such surgery on postoperative adjuvant therapy and survival. METHODS: We reviewed our institutional experience with adult patients who underwent an adrenal metastasectomy from 1997 to 2013. We assessed preoperative tumor size, operating room (OR) time, status of resection margin, and length of stay (LOS), as well as oncological outcomes including the use of adjuvant chemotherapy and radiotherapy within 1 year of surgery and 5-year survival. The χ (2) test, Mann-Whitney U test, and Kaplan-Meier curve were used for statistical analysis. RESULTS: Thirty-eight patients were identified. Lung was the primary site of malignancy (52.6 % of cases). Of the metastasectomies, 55.2 % (n = 21) were performed laparoscopically and 44.7 % (n = 17) were open. In the laparoscopic group, median tumor size was 2.6 cm versus 4.8 cm in the open group (p = 0.09). Median OR time and complication rates were similar between the 2 groups. The laparoscopic group, however, trended toward a shorter LOS (3 days laparoscopic vs. 4 days for open; p = 0.07). At 1 year, 37 % of all patients had not required any adjuvant chemotherapy or adjuvant radiotherapy. CONCLUSIONS: This series confirms that adrenal metastasectomy leads to favorable oncological outcomes in select patient groups, with over one-third of patients not requiring adjuvant therapy for at least 1 year after their resection. Laparoscopic approach leads to excellent oncological resection margins without increasing OR time and with a possible reduction in LOS.


Asunto(s)
Neoplasias de las Glándulas Suprarrenales/secundario , Neoplasias de las Glándulas Suprarrenales/cirugía , Adrenalectomía/métodos , Laparoscopía , Metastasectomía/métodos , Neoplasias de las Glándulas Suprarrenales/mortalidad , Estudios de Factibilidad , Femenino , Estudios de Seguimiento , Humanos , Masculino , Massachusetts/epidemiología , Persona de Mediana Edad , Estudios Retrospectivos , Tasa de Supervivencia/tendencias , Resultado del Tratamiento
6.
Obes Surg ; 2024 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-38867101

RESUMEN

PURPOSE: The incidence of unresolved postoperative reflux after bariatric surgery varies considerably. Consistent perioperative patient characteristics predictive of unresolved reflux remain unknown. We leverage our institution's comprehensive preoperative esophageal testing to identify predictors of postoperative reflux. MATERIALS AND METHODS: We performed a single-center retrospective review of adult patients with preoperative reflux symptoms who underwent either vertical sleeve gastrectomy (VSG) or Roux-en-Y gastric bypass (RYGB) from 2015 to 2021. All patients had pH and high-resolution manometry preoperatively. Predictors of postoperative unresolved reflux at 1 year were explored via Fisher's exact test, Kruskal Wallis test, and univariate logistic regression. RESULTS: Unresolved reflux was higher in patients undergoing VSG (n = 60/129,46.5%) vs. RYGB (n = 19/98, 19.4%). Median DeMeester scores were higher (22 vs. 13, p = .07) along with rates of ineffective esophageal motility (IEM) (31.6 vs. 8.9%, p = .01) in the 19 (19.3%) patients with unresolved postoperative reflux after RYGB compared to the resolved RYGB reflux cohort. Sixty (46.5%) of VSG patients had unresolved postoperative reflux. The VSG unresolved reflux cohort had similar median DeMeester and IEM incidence to the resolved VSG group but more preoperative dysphagia (13.3% vs. 2.9%, p = .04) and higher preoperative PPI use (56.7 vs. 39.1%, p = .05). In univariate analysis, only IEM was predictive of unresolved reflux after RYGB (OR 4.74, 95% CI 1.37, 16.4). CONCLUSION: Unresolved reflux was higher after VSG. Preoperative IEM predicted unresolved reflux symptoms after RYGB. In VSG patients, preoperative dysphagia symptoms and PPI use predicted unresolved reflux though lack of correlation to objective testing highlights the subjective nature of symptoms and the challenges in predicting postoperative symptomatology.

7.
Chemphyschem ; 14(13): 3121-30, 2013 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-23788291

RESUMEN

We present a solid-state NMR study of H2 molecules confined inside the cavity of C70 fullerene cages over a wide range of temperatures (300 K to 4 K). The proton NMR spectra are consistent with a model in which the dipole-dipole coupling between the ortho-H2 protons is averaged over the rotational/translational states of the confined quantum rotor, with an additional chemical shift anisotropy δ(H)(CSA)=10.1 ppm induced by the carbon cage. The magnitude of the chemical shift anisotropy is consistent with DFT estimates of the chemical shielding tensor field within the cage. The experimental NMR data indicate that the ground state of endohedral ortho-H2 in C70 is doubly degenerate and polarized transverse to the principal axis of the cage. The NMR spectra indicate significant magnetic alignment of the C70 long axes along the magnetic field, at temperatures below ~10 K.

8.
Obes Surg ; 33(8): 2527-2532, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37407773

RESUMEN

BACKGROUND: Healthcare-associated activity accounts for 10% of the United States' carbon dioxide (CO2) emissions. Using telemedicine for bariatric surgery evaluations decreases emissions and reduces patient burden during the multiple required interdisciplinary visits. After adopting telemedicine during COVID, our clinic continues to utilize telemedicine for preoperative bariatric evaluations. We evaluated the reduced environmental impact associated with this practice. METHODS: A retrospective review of all new evaluations for vertical sleeve gastrectomy (SG) or Roux-en Y gastric bypass (RYGB) from 2019 and 2021 was conducted. The 2019 year represents pre-pandemic, in-person evaluations and 2021 represents telemedicine evaluations during the COVID pandemic. Carbon emissions were calculated using the Environmental Protection Agency's (EPA's) validated formula of 404g CO2 per car-mile. Preoperative evaluation time was calculated from the initial clinic visit to the operation date. RESULTS: There were 51 patients in the 2019 cohort and 55 patients in the 2021 cohort. In the 2019 in-person cohort, there was significantly more kg of estimated CO2 emitted (10,225 vs. 2011.4, p<.001) compared to the 2021 cohort. For time required to complete the preoperative workup, there was no statistically significant difference between the two groups (162 days vs. 193 days, p=.226). The attrition rate was lower in the 2021 cohort (22.22% v. 35.9%, p<.001). CONCLUSIONS: Implementation of telemedicine for bariatric preoperative evaluations reduced patient travel, carbon emissions, and improved attrition rate. We encourage bariatric providers to use telemedicine as we believe this eases patient burdens and, with wider adoption, could significantly reduce our carbon footprint.


Asunto(s)
Cirugía Bariátrica , COVID-19 , Derivación Gástrica , Obesidad Mórbida , Telemedicina , Humanos , Estados Unidos , Obesidad Mórbida/cirugía , Huella de Carbono , Dióxido de Carbono , COVID-19/epidemiología , Estudios Retrospectivos , Gastrectomía , Resultado del Tratamiento
9.
JAMA Surg ; 157(9): 765-770, 2022 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-35704308

RESUMEN

Importance: Surgical complications associated with perioperative hyperglycemia are conventionally associated with diabetes, but, paradoxically, prior cohort studies have found that patients without diabetes have greater risk of complications at similar levels of hyperglycemia compared with patients with diabetes. Objective: To describe the association between perioperative hyperglycemia and surgical complications in a population of surgical patients without diabetes receiving routine blood glucose testing and insulin administration and to evaluate the potential correlation of perioperative hyperglycemia. Design, Setting, and Participants: This retrospective cohort study of National Surgical Quality Improvement Program-defined complications after operation took place at a single academic medical center hospital from January 2013 to October 2016. Consecutive patients undergoing general, vascular, and gynecologic operations who were expected to have at least a 48-hour admission were included. Hyperglycemia was defined as blood glucose level of 140 mg/dL or higher within 24 hours after surgery. Multivariate regression was used to assess the association of hyperglycemia and complications, stratified by hyperglycemia severity and adjusted for diabetes status. Analysis began in February 2022. Exposures: Routine blood glucose testing and insulin administration. Main Outcomes and Measures: The main outcomes are odds of experiencing perioperative hyperglycemia and postoperative complication, comparing patients with and without diabetes. Results: A total of 7634 patients (mean [SD] age, 53.5 [15.1] years; 6664 patients without diabetes [83.3%] and 970 patients with diabetes [17.7%]) underwent general (6204 [81.3%]), vascular (208 [2.7%]), and gynecologic (1222 [16%]) operations. Of these, 5868 (77%) had blood glucose testing (4899 individuals without diabetes [73.5%] and 969 [99.9%] with diabetes). Hyperglycemia occurred in 882 patients with diabetes (91%) and 2484 patients without diabetes (50.7%). Of those with blood glucose level more than 180 mg/dL, 1388 (72.7%) received insulin (658 patients with diabetes who had hyperglycemia [91%] and 680 patients without diabetes who had hyperglycemia [61%]). Adjusted odds of experiencing a complication were 83% greater for patients without vs with diabetes at blood glucose level of 140 to 179 mg/dL (odds ratio, 1.83 [95% CI, 0.93-3.6]), 49% greater for blood glucose level of 180 to 249 mg/dL (odds ratio, 1.49 [95% CI, 1.06-2.11]), and 88% greater for blood glucose level more than 250 mg/dL (odds ratio, 1.88 [95% CI, 1.11-3.17]). A similar trend was observed for serious complications. Insulin may mitigate the association of hyperglycemia and complications in patients without diabetes. Conclusions and Relevance: In this study, with near universal blood glucose testing and frequent insulin use, patients without diabetes paradoxically had worse outcomes than patients with diabetes at similar levels of hyperglycemia. Insulin may mitigate this effect and broader use may improve outcomes.


Asunto(s)
Diabetes Mellitus , Hiperglucemia , Glucemia , Diabetes Mellitus/epidemiología , Femenino , Humanos , Hiperglucemia/epidemiología , Insulina/uso terapéutico , Persona de Mediana Edad , Estudios Retrospectivos
10.
Clin Transl Sci ; 15(6): 1460-1471, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35213790

RESUMEN

The prevalence of obesity continues to rise, underscoring the need to better understand the pathways mediating adipose tissue (AT) expansion. All-trans-retinoic acid (atRA), a bioactive vitamin A metabolite, regulates adipogenesis and energy metabolism, and, in rodent studies, aberrant vitamin A metabolism appears a key facet of metabolic dysregulation. The relevance of these findings to human disease is unknown, as are the specific enzymes implicated in vitamin A metabolism within human AT. We hypothesized that in human AT, family 1A aldehyde dehydrogenase (ALDH1A) enzymes contribute to atRA biosynthesis in a depot-specific manner. To test this hypothesis, parallel samples of subcutaneous and omental AT from participants (n = 15) were collected during elective abdominal surgeries to quantify atRA biosynthesis and key atRA synthesizing enzymes. ALDH1A1 was the most abundant ALDH1A isoform in both AT depots with expression approximately twofold higher in omental than subcutaneous AT. ALDH1A2 was detected only in omental AT. Formation velocity of atRA was approximately threefold higher (p = 0.0001) in omental AT (9.8 [7.6, 11.2]) pmol/min/mg) than subcutaneous AT (3.2 [2.1, 4.0] pmol/min/mg) and correlated with ALDH1A2 expression in omental AT (ß-coefficient = 3.07, p = 0.0007) and with ALDH1A1 expression in subcutaneous AT (ß-coefficient = 0.13, p = 0.003). Despite a positive correlation between body mass index (BMI) and omental ALDH1A1 protein expression (Spearman r = 0.65, p = 0.01), BMI did not correlate with atRA formation. Our findings suggest that ALDH1A2 is the primary mediator of atRA formation in omental AT, whereas ALDH1A1 is the principal atRA-synthesizing enzyme in subcutaneous AT. These data highlight AT depot as a critical variable for defining the roles of retinoids in human AT biology.


Asunto(s)
Tejido Adiposo , Vitamina A , Tejido Adiposo/metabolismo , Humanos , Obesidad/metabolismo , Grasa Subcutánea , Tretinoina/metabolismo
11.
J Am Chem Soc ; 133(36): 14232-5, 2011 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-21842909

RESUMEN

The photochemical interconversion of the two allotropes of the hydrogen molecule [para-H(2) (pH(2)) and ortho-H(2) (oH(2))] incarcerated inside the fullerene C(70) (pH(2)@C(70) and oH(2)@C(70), respectively) is reported. Photoexcitation of H(2)@C(70) generates a fullerene triplet state that serves as a spin catalyst for pH(2)/oH(2) conversion. This method provides a means of changing the pH(2)/oH(2) ratio inside C(70) by simply irradiating H(2)@C(70) at different temperatures, since the equilibrium ratio is temperature-dependent and the electronic triplet state of the fullerene produced by absorption of the photon serves as an "on-off" spin catalyst. However, under comparable conditions, no photolytic pH(2)/oH(2) interconversion was observed for H(2)@C(60), which was rationalized by the significantly shorter triplet lifetime of H(2)@C(60) relative to H(2)@C(70).

12.
Acc Chem Res ; 43(2): 335-45, 2010 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-19902960

RESUMEN

One of the early triumphs of quantum mechanics was Heisenberg's prediction, based on the Pauli principle and wave function symmetry arguments, that the simplest molecule, H(2), should exist as two distinct species-allotropes of elemental hydrogen. One allotrope, termed para-H(2) (pH(2)), was predicted to be a lower energy species that could be visualized as rotating like a sphere and possessing antiparallel ( upward arrow downward arrow) nuclear spins; the other allotrope, termed ortho-H(2) (oH(2)), was predicted to be a higher energy state that could be visualized as rotating like a cartwheel and possessing parallel ( upward arrow upward arrow) nuclear spins. This remarkable prediction was confirmed by the early 1930s, and pH(2) and oH(2) were not only separated and characterized but were also found to be stable almost indefinitely in the absence of paramagnetic "spin catalysts", such as molecular oxygen, or traces of paramagnetic impurities, such as metal ions. The two allotropes of elemental hydrogen, pH(2) and oH(2), may be quantitatively incarcerated in C(60) to form endofullerene guest@host complexes, symbolized as pH(2)@C(60) and oH(2)@C(60), respectively. How does the subtle difference in nuclear spin manifest itself when hydrogen allotropes are incarcerated in a buckyball? Can the incarcerated "guests" communicate with the outside world and vice versa? Can a paramagnetic spin catalyst in the outside world cause the interconversion of the allotropes and thereby effect a chemical transformation inside a buckyball? How close are the measurable properties of H(2)@C(60) to those computed for the "quantum particle in a spherical box"? Are there any potential practical applications of this fascinating marriage of the simplest molecule, H(2), with one of the most beautiful of all molecules, C(60)? How can one address such questions theoretically and experimentally? A goal of our studies is to produce an understanding of how the H(2) guest molecules incarcerated in the host C(60) can "communicate" with the chemical world surrounding it. This world includes both the "walls" of the incarcerating host (the carbon atom "bricks" that compose the wall) and the "outside" world beyond the atoms of the host walls, namely, the solvent molecules and selected paramagnetic molecules added to the solvent that will have special spin interactions with the H(2) inside the complex. In this Account, we describe the temperature dependence of the equilibrium of the interconversion of oH(2)@C(60) and pH(2)@C(60) and show how elemental dioxygen, O(2), a ground-state triplet, is an excellent paramagnetic spin catalyst for this interconversion. We then describe an exploration of the spin spectroscopy and spin chemistry of H(2)@C(60). We find that H(2)@C(60) and its isotopic analogs, HD@C(60) and D(2)@C(60), provide a rich and fascinating platform on which to investigate spin spectroscopy and spin chemistry. Finally, we consider the potential extension of spin chemistry to another molecule with spin isomers, H(2)O, and the potential applications of the use of pH(2)@C(60) as a source of latent massive nuclear polarization.


Asunto(s)
Fulerenos/química , Hidrógeno/química , Catálisis , Espectroscopía de Resonancia Magnética , Oxígeno/química
13.
J Am Chem Soc ; 132(12): 4042-3, 2010 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-20175520

RESUMEN

The interconversion of ortho-hydrogen (oH(2)) and para-hydrogen (pH(2)), the two nuclear spin isomers of dihydrogen, requires a paramagnetic spin catalyst such as a nitroxide. We report the design and demonstration of spin catalysis of the interconversion of oH(2) and pH(2) incarcerated in an endofullerene based on a reversible nitroxide/hydroxylamine system. The system is an example of a reversible magnetic spin catalysis switch that can increase the rate of interconversion of the nuclear spin isomers of H(2) by a factor of approximately 10(4).

14.
Artículo en Inglés | MEDLINE | ID: mdl-20038194

RESUMEN

BACKGROUND: Generic ciclosporin A modified (CsA) does not have an equivalent pharmacokinetic profile to branded CsA in some transplant populations, potentially leading to negative clinical consequences and increased long-term costs. OBJECTIVE: To assess direct healthcare costs for de novo renal transplant recipients in the US receiving branded versus generic CsA in the first month after transplantation. METHODS: Administrative claims data from eight private US health plans were linked to the Organ Procurement and Transplantation Network data. A total of 227 renal transplant cases between 1996 and 2004 were included: 183 were dispensed branded CsA and 44 received generic CsA. Log transformed multiple linear regression was used to model total first-year healthcare costs after the initial CsA claim, controlling for both patient demographics and clinical characteristics and clustering at the transplant centre level. RESULTS: After controlling for patient factors and pre-CsA costs, total healthcare costs were significantly higher (p = 0.04) for patients receiving generic CsA versus branded CsA. The main driver for the difference was the cost associated with immunosuppressants other than CsA (p = 0.01). CONCLUSION: Despite initial perceived cost savings associated with generic CsA, de novo renal transplant recipients incurred greater total healthcare costs than those treated with branded CsA. Patients receiving generic CsA may need higher doses or other immunosuppressants to maintain the transplanted kidney than patients receiving branded CsA. Providers and payers need to be aware of potential differences in total healthcare costs between formulations of bioequivalent critical-dose drugs to make the best choice for patient care.


Asunto(s)
Ciclosporina/economía , Costos de la Atención en Salud , Trasplante de Riñón/economía , Adulto , Ahorro de Costo/métodos , Ciclosporina/farmacocinética , Ciclosporina/uso terapéutico , Medicamentos Genéricos/economía , Medicamentos Genéricos/farmacocinética , Medicamentos Genéricos/uso terapéutico , Femenino , Humanos , Revisión de Utilización de Seguros , Masculino , Persona de Mediana Edad , Equivalencia Terapéutica , Estados Unidos
15.
J Gen Intern Med ; 24(1): 99-104, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19023629

RESUMEN

BACKGROUND: For women with early stage breast cancer, physician-patient discussion of breast reconstruction is an essential step in their participation in the decision-making process for their treatments. This study examines sociodemographic variation of physician-patient discussion of breast reconstruction and explores the impact of this discussion on the use of breast reconstruction. METHODS: We used data from the Los Angeles Women's Study, a population-based study of women 50 years and older with breast cancer. Bivariate and multivariate logistic regression models were used to estimate the impact of patient and hospital characteristics on self-reported receipt of physician-patient discussion and use of breast reconstruction. RESULTS: Of 315 post-mastectomy women, 81% and 27% reported physician-patient discussion and use of breast reconstruction, respectively. In multivariable analysis, women with an annual income <$20,000 were less likely to have physician-patient discussion than women with annual income > or =$40,000 (OR = 0.23, 95% CI 0.07-0.82). Among the subset of women with physician-patient discussion, chest wall radiation, a known characteristic associated with higher rates of reconstruction complications, became an additional significant negative predictor of reconstruction. CONCLUSIONS: Lower income women are at risk of not receiving physician-patient discussion of breast reconstruction. Physician-patient discussion of breast reconstruction appears to decrease the use of breast reconstruction among women with clinical characteristics associated with higher rates of reconstruction complications and failure. This highlights the need for interventions to increase physician-patient discussion of breast reconstruction among lower income women.


Asunto(s)
Comunicación , Mamoplastia/psicología , Participación del Paciente/psicología , Relaciones Médico-Paciente , Anciano , Neoplasias de la Mama/economía , Neoplasias de la Mama/psicología , Neoplasias de la Mama/cirugía , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Mamoplastia/economía , Mamoplastia/tendencias , Mastectomía/economía , Mastectomía/psicología , Mastectomía/tendencias , Persona de Mediana Edad , Participación del Paciente/economía , Participación del Paciente/tendencias , Satisfacción del Paciente/economía , Factores Socioeconómicos
16.
Med Decis Making ; 29(1): 51-60, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19129157

RESUMEN

BACKGROUND: More than one-quarter of Korean American children are uninsured, and many are eligible for children's health insurance programs. The objective of this study is to evaluate the effectiveness and cost-effectiveness of different school-based health insurance strategies to provide coverage to uninsured Korean American children. METHOD: The authors used a quasi-experimental nonequivalent control group design, conducted from July to December 2005 in Los Angeles, California. The subjects were in 3 groups/schools (n = 1181). Parents received a variation of outreach methods (i.e., information sheets, school site presentations, automated telephone messages, personal telephone calls) and application assistance (i.e., telephone helpline, on-site assistance). The authors used bivariate and multivariable analysis to assess effectiveness. Cost-effectiveness was performed using a 3-stage model and Monte Carlo simulation. RESULTS: Of the uninsured in the intensive intervention group, 41% applied for insurance compared with 13% of the control group (P = 0:002). This success was due to personal telephone calls. Of the uninsured in the intensive intervention group, 23% enrolled in insurance compared with 10% of the control group (P = 0:048). The most common reason reported by parents for nonenrollment despite assistance was failure to mail in the application. Despite the small increase in insurance enrollment from the intensive intervention strategy compared with the control group, it is cost-effective. CONCLUSIONS: Personal telephone calls are effective in increasing outreach for children's health insurance application. However, more research is needed to investigate why parents fail to mail in the application. Ultimately, insuring more children will result in cost-effective improvements in quality-adjusted life years.


Asunto(s)
Asiático , Cobertura del Seguro/economía , Seguro de Salud/economía , Pacientes no Asegurados , Servicios de Salud Escolar/economía , Niño , Protección a la Infancia , Análisis Costo-Beneficio , Árboles de Decisión , Femenino , Humanos , Corea (Geográfico)/etnología , Los Angeles , Masculino , Teléfono
17.
J Am Chem Soc ; 130(23): 7206-7, 2008 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-18473461

RESUMEN

A 15N-labeled nitroxide was incarcerated into an octa acid nanocapsule, which was confirmed by 1H NMR and EPR spectroscopy. Electron paramagnetic interaction between the 15N-labeled incarcerated nitroxide and a 14N-labeled free nitroxide in the external aqueous solution was observed by EPR spectroscopy. The observation of spin-spin interaction, through the walls of the cancer and is reflected in the simultaneous line-broadening of both the 15N-labeled and 14N-labeled nitroxides. The computer-assisted analysis of the EPR data further provides direct information on the motion and the polarity of both the incarcerated paramagnetic nitroxide and the nitroxides in the external bulk aqueous phase. We also show how communication between an incarcerated guest and molecules in the bulk solvent can be enhanced or inhibited by supramolecular factors such as Coulombic attraction or repulsion between a charged guest@host complex (incarcerated 15N nitroxide) and charged molecules in the aqueous phase.

18.
J Am Chem Soc ; 130(32): 10506-7, 2008 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-18642816

RESUMEN

The interconversion of the two allotropes of the hydrogen molecule (para-H2 and ortho-H2) incarcerated inside the fullerene C60 is reported (oH2@C60 and pH2@C60, respectively). For conversion, oH2@C60 was adsorbed at the external surface of the zeolite NaY and immersed into liquid oxygen at 77 K. Equilibrium was reached in less than 0.5 h. Rapid removal of oxygen provides a sample of enriched pH2@C60 that is stable for many days in the absence of paramagnetic catalysts (half-life approximately 15 days). Enriched pH2@C60 is nonvolatile and soluble in organic solvents. At room temperature in the presence of a paramagnetic catalyst (dissolved O2 or the nitroxide Tempo) a slow back conversion into oH2@C60 was observed by 1H NMR. A bimolecular rate constant for conversion of pH2@C60 to oH2@C60 using Tempo of kTempo approximately 4 x 10-5 M-1 s-1 was observed, which is approximately 3 orders of magnitudes slower than that for dissolved pH2 in organic solvents which is not protected by the C60 shell.

19.
Med Care ; 46(11): 1157-62, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18953226

RESUMEN

BACKGROUND: When 2 treatment choices (ie, mastectomy vs. breast conserving therapy) show no difference in a primary clinical outcome (ie, survival), patient satisfaction becomes an important marker of the quality of care received. OBJECTIVES: To assess the impact of physician-patient discussion of primary surgical treatment outcomes on patients' satisfaction with medical care (MC) among women with incident breast cancer (BC). METHOD: We used self-report data of a population-based survey of 495 women >or=50 years of age with stage I-II BC in Los Angeles, California in 2000 conducted a mean of 7.5 and 24 months after diagnosis. Using multivariable analyses, we evaluated the impact of physician-patient outcome discussions (ie, BC recurrence, BC survival, breast appearance, and arm swelling/pain/movement difficulty) on patient satisfaction at baseline and follow-up. RESULTS: Most women were satisfied with their MC (>65%). More than half reported physician-patient discussions of BC recurrence (54%), breast appearance (50%), and arm pain/swelling/movement difficulty (55%). Thirty-one percent discussed BC survival. Women who discussed arm swelling, pain, movement difficulty were significantly more likely to be satisfied at baseline (odds ratio: 1.8, 95% confidence interval: 1.1-3.0, P < 0.05) and follow-up (odds ratio: 1.9, 95% confidence interval: 1.2-3.0, P > 0.01). The more treatment outcomes patients discussed with their physicians, the higher patient satisfaction ratings were at baseline and follow-up. CONCLUSIONS: Physician-patient discussions of BC treatment outcomes were highly correlated with patients' satisfaction with overall MC regardless of the procedure received. This suggests that the quality of BC care should include assessments of physician-patient communication.


Asunto(s)
Neoplasias de la Mama/cirugía , Satisfacción del Paciente , Relaciones Médico-Paciente , Anciano , Neoplasias de la Mama/epidemiología , Femenino , Humanos , Estudios Longitudinales , Persona de Mediana Edad , Recurrencia Local de Neoplasia , Complicaciones Posoperatorias/epidemiología , Factores Socioeconómicos , Resultado del Tratamiento
20.
J Org Chem ; 73(24): 9668-74, 2008 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-18986202

RESUMEN

The stoichiometric reduction of N-carbophenoxypyridinium tetraphenylborate (6) by CpRu(P-P)H (Cp = eta(5)-cyclopentadienyl; P-P = dppe, 1,2-bis(diphenylphosphino)ethane, or dppf, 1,1'-bis(diphenylphosphino)ferrocene), and Cp*Ru(P-P)H (Cp* = eta(5)-pentamethylcyclopentadienyl; P-P = dppe) gives mixtures of 1,2- and 1,4-dihydropyridines. The stoichiometric reduction of 6 by Cp*Ru(dppf)H (5) gives only the 1,4-dihydropyridine, and 5 catalyzes the exclusive formation of the 1,4-dihydropyridine from 6, H(2), and 2,2,6,6-tetramethylpiperidine. In the stoichiometric reductions, the ratio of 1,4 to 1,2 product increases as the Ru hydrides become better one-electron reductants, suggesting that the 1,4 product arises from a two-step (e(-)/H(*)) hydride transfer. Calculations at the UB3LYP/6-311++G(3df,3pd)//UB3LYP/6-31G* level support this hypothesis, indicating that the spin density in the N-carbophenoxypyridinium radical (13) resides primarily at C4, while the positive charge in 6 resides primarily at C2 and C6. The isomeric dihydropyridines thus result from the operation of different mechanisms: the 1,2 product from a single-step H(-) transfer and the 1,4 product from a two-step (e(-)/H(*)) transfer.


Asunto(s)
Compuestos de Piridinio/química , Catálisis , Electroquímica , Espectroscopía de Resonancia por Spin del Electrón , Hidrogenación , Indicadores y Reactivos , Isomerismo , Espectroscopía de Resonancia Magnética , Oxidación-Reducción , Protones , Rutenio/química
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