Use of δ18Oatm in dating a Tibetan ice core record of Holocene/Late Glacial climate.

Ice cores from the northwestern Tibetan Plateau (NWTP) contain long records of regional climate variability, but refrozen meltwater and dust in these cores has hampered development of robust timescales. Here, we introduce an approach to dating the ice via the isotopic composition of atmospheric O2 in air bubbles (δ18Oatm), along with annual layer counting and radiocarbon dating. We provide a robust chronology for water isotope records (δ18Oice and d-excess) from three ice cores from the Guliya ice cap in the NWTP. The measurement of δ18Oatm, although common in polar ice core timescales, has rarely been used on ice cores from low-latitude, high-altitude glaciers due to (1) low air pressure, (2) the common presence of refrozen melt that adds dissolved gases and reduces the amount of air available for analysis, and (3) the respiratory consumption of molecular oxygen (O2) by micro-organisms in the ice, which fractionates the δ18O of O2 from the atmospheric value. Here, we make corrections for melt and respiration to address these complications. The resulting records of water isotopes from the Guliya ice cores reveal climatic variations over the last 15,000 y, the timings of which correspond to those observed in independently dated lake and speleothem records and confirm that the Guliya ice cap existed before the Holocene. The millennial-scale drivers of δ18Oice are complex and temporally variable; however, Guliya δ18Oice values since the mid-20th century are the highest since the beginning of the Holocene and have increased with regional air temperature.

Assessing Telehealth Through the Lens of the Provider: Considerations for the Post-COVID-19 Era.

Introduction: Following the coronavirus disease (COVID-19) pandemic restrictions, many health care systems turned to telehealth as an alternative to in-person care. Current literature describes sustained patient satisfaction levels with virtual care throughout the pandemic era. However, provider opinions on the transforming landscape are largely unknown. Objectives: The aim of this study is to better understand provider intentions and limitations to telehealth adoption, along with preferences by various specialties and in various settings. Methods: A mixed-methods study design was used. An attitudinal survey was sent to 2,633 health care providers at a large, quaternary, integrated health system. The survey collected deidentified quantitative and qualitative data on factors influencing provider use, satisfaction, and concerns with telehealth during and after the initial pandemic-era restrictions. Results: Five hundred eighteen providers participated in the survey. Utilization of telehealth was largely motivated by (1) improving patient access (mean 29.3%; range 28-31.6%) and (2) patient interest (mean 23%; range 17.1-28.8%). Barriers included (1) technology limitations (mean 16.1%; range 12.4-23.8%) and (2) reimbursement uncertainties (mean 15.2%; range 4.8-18.8%). Preference for virtual care was reported to be highest in ambulatory settings, including direct-to-patient care and outpatient care. Discussion: Provider preference for telehealth, regardless of specialty or health care setting, revolves around a consumer-centric care delivery model, with increased access to care being a central theme. While provider values are patient oriented, this study found that concerns included connectivity, quality, and patient privacy. Amid changing care standards and regulations, provider preference is supportive of virtual care platforms, both now and postpandemic.

Aminotransferase levels are associated with cardiometabolic risk above and beyond visceral fat and insulin resistance: the Framingham Heart Study.

OBJECTIVE: We sought to characterize associations between aminotransferase levels and cardiometabolic risk after accounting for visceral adipose tissue and insulin resistance. METHODS AND RESULTS: Participants (n=2621) from the Framingham Heart Study (mean age 51, 49.8% women) were included. Sex-specific linear and logistic regressions were used to evaluate associations between aminotransferase levels and cardiometabolic risk factors. In multivariable models, increased alanine aminotransferase levels were associated with elevated blood pressure, fasting plasma glucose, and triglycerides and lower high-density lipoprotein levels (all P≤0.007). Furthermore, each 1-SD increase in alanine aminotransferase corresponded to an increased odds of hypertension, diabetes mellitus, the metabolic syndrome, impaired fasting glucose, and insulin resistance estimated by the homeostasis model assessment of insulin resistance (odds ratio, 1.29-1.85, all P≤0.002). Associations with alanine aminotransferase persisted after additional adjustment for visceral adipose tissue, insulin resistance, and body mass index with the exception of high-density lipoprotein cholesterol in both sexes and blood pressure in women. Results were materially unchanged when moderate drinkers were excluded, when the sample was restricted to those with alanine aminotransferase <40 U/L, and when the sample was restricted to those without diabetes mellitus. Similar trends were observed for aspartate aminotransferase levels, but associations were more modest. CONCLUSIONS: Aminotransferase levels are correlated with multiple cardiometabolic risk factors above and beyond visceral adipose tissue and insulin resistance.

Development and reproducibility of a computed tomography-based measurement of renal sinus fat.

BACKGROUND: Renal sinus fat may mediate obesity-related vascular disease, although this fat depot has not been assessed in a community-based sample. We sought to develop a protocol to quantify renal sinus fat accumulation using multi-detector computed tomography (MDCT). METHODS: Protocol development was performed in participants in the Framingham Offspring cohort who underwent MDCT. Volumetric renal sinus fat was measured separately within the right and left kidneys, and renal sinus fat area within a single MDCT scan slice was measured in the right kidney. Due to the high correlation of volumetric and single-slice renal sinus fat in the right kidney (Pearson correlation [r] = 0.85, p < 0.0001), we optimized a single-slice protocol to capture renal sinus fat in the right kidney alone. Pearson correlation coefficients were used to compare to assess the correlation of volumetric and single-slice renal sinus fat in the right kidney with other measures of adiposity. Inter- and intra-reader reproducibility was assessed using intra-class correlation coefficients. RESULTS: Single-slice measurements were obtained in 92 participants (mean age 60 years, 49% women, median renal sinus fat 0.43 cm2). Intra- and inter-reader intra-class correlation coefficients were 0.93 and 0.86, respectively. Single-slice renal sinus fat was correlated with body mass index (r = 0.35, p = 0.0006), waist circumference (r = 0.31, p = 0.003), and abdominal visceral fat (r = 0.48, p < 0.0001). Similar correlations were observed for volumetric renal sinus fat in the right kidney. CONCLUSIONS: Measuring renal sinus fat is feasible and reproducible using MDCT scans in a community-based sample.

Fatty kidney, hypertension, and chronic kidney disease: the Framingham Heart Study.

Ectopic fat depots may mediate local and systemic disease. Animal models of diet-induced obesity demonstrate increased fat accumulation in the renal sinus. The association of renal sinus fat with hypertension, chronic kidney disease, and other metabolic disorders has not been studied in a large, community-based sample. Participants from the Framingham Heart Study (n=2923; mean age: 54 years; 51% women) underwent quantification of renal sinus fat area using computed tomography. High renal sinus fat ("fatty kidney") was defined using sex-specific 90th percentiles in a healthy referent subsample. Multivariable linear and logistic regression was used to model metabolic risk factors as a function of fatty kidney and log-transformed renal sinus fat. Multivariable models were adjusted for age, sex, and outcome-specific covariates and then additionally adjusted for body mass index or abdominal visceral adipose tissue. The prevalence of fatty kidney was 30.1% (n=879). Individuals with fatty kidney had a higher odds ratio (OR) of hypertension (OR: 2.12; P<0.0001), which persisted after adjustment for body mass index (OR: 1.49; P<0.0001) or visceral adipose tissue (OR: 1.24; P=0.049). Fatty kidney was also associated with an increased OR for chronic kidney disease (OR: 2.30; P=0.005), even after additionally adjusting for body mass index (OR: 1.86; P=0.04) or visceral adipose tissue (OR: 1.86; P=0.05). We observed no association between fatty kidney and diabetes mellitus after adjusting for visceral adipose tissue. In conclusion, fatty kidney is a common condition that is associated with an increased risk of hypertension and chronic kidney disease. Renal sinus fat may play a role in blood pressure regulation and chronic kidney disease.

Receipt of appropriate surgical care for Medicare beneficiaries with cancer.

OBJECTIVE: To investigate receipt of appropriate surgical care in Medicare beneficiaries with cancer. DESIGN: Retrospective cohort study. SETTING: National Surveillance, Epidemiology, and End Results registry linked to Medicare claims data. PATIENTS: Fee-for-service Medicare patients aged 65 years or older who underwent a definitive surgical resection for breast, colon, gastric, rectal, or thyroid cancer diagnosed between January 2000 and December 2005. Claims data were available from January 1999 through December 2007. MAIN OUTCOME MEASURES: Receipt of care concordant with established practice guidelines in surgical oncology in the aggregate and by hospital. RESULTS: Concordance with guidelines was greater than 90% for 7 of 11 measures. All guidelines regarding adjuvant therapy had concordance rates greater than 90%. Only 2 of 5 measures for nodal management had concordance rates greater than 90%. At least 50% of hospitals provided guideline-concordant care to 100% of their patients for 6 of 11 guidelines. Patients receiving appropriate care tended to be younger, healthier, white, and more affluent, to have less advanced disease, and to live in the Midwest. CONCLUSIONS: We found a high level of concordance with guidelines in some domains of surgical oncology care but far less so in others, particularly for gastric and colon nodal management. Given the current national focus on improving the quality of health care, surgeons must focus on generating data to define appropriate care and translating those data into everyday practice.

Pericardial fat, intrathoracic fat, and measures of left ventricular structure and function: the Framingham Heart Study.

BACKGROUND: Pericardial fat has been implicated in the pathogenesis of obesity-related cardiovascular disease. Whether the associations of pericardial fat and measures of cardiac structure and function are independent of the systemic effects of obesity and visceral adiposity has not been fully explored. METHODS AND RESULTS: Participants from the Framingham Heart Study (n=997; 54.4% women) underwent chest and abdominal computed tomography and cardiovascular magnetic resonance imaging between 2002 and 2005. Pericardial fat, intrathoracic fat, and visceral adipose tissue quantified from multidetector computed tomography, along with body mass index and waist circumference, were examined in relation to cardiovascular magnetic resonance measures of left ventricular (LV) mass, LV end-diastolic volume, and left atrial dimension. In women, pericardial fat (r=0.20 to 0.35, P<0.001), intrathoracic fat (r=0.25 to 0.37, P<0.001), visceral adipose tissue (r=0.24 to 0.45, P<0.001), body mass index (r=0.36 to 0.53, P<0.001), and waist circumference (r=0.30 to 0.48, P<0.001) were directly correlated with LV mass, LV end-diastolic volume, and left atrial dimension. In men, pericardial fat (r=0.19 to 0.37, P<0.001), intrathoracic fat (r=0.17 to 0.31, P<0.001), visceral adipose tissue (r=0.19 to 0.36, P<0.001), body mass index (r=0.32 to 0.44, P<0.001), and waist circumference (r=0.34 to 0.44, P<0.001) were directly correlated with LV mass and left atrial dimension, but LV end-diastolic volume was not consistently associated with adiposity measures. Associations persisted after multivariable adjustment but not after additional adjustment for body weight and visceral adipose tissue, except for pericardial fat and left atrial dimension in men. CONCLUSIONS: Pericardial fat is correlated with cardiovascular magnetic resonance measures, but the association is not independent of or stronger than other ectopic fat stores or proxy measures of visceral adiposity. An important exception is left atrial dimension in men. These results suggest that the systemic effects of obesity on cardiac structure and function may outweigh the local pathogenic effects of pericardial fat.

Abdominal subcutaneous adipose tissue: a protective fat depot?

OBJECTIVE: Obesity is associated with increased metabolic and cardiovascular risk. The ectopic fat hypothesis suggests that subcutaneous fat may be protective, but this theory has yet to be fully explored. RESEARCH DESIGN AND METHODS: Participants from the Framingham Heart Study (n = 3,001, 48.5% women) were stratified by visceral adipose tissue (VAT) into sex-specific tertiles. Within these tertiles, age-adjusted abdominal subcutaneous adipose tissue (SAT) tertiles were examined in relation to cardiometabolic risk factors. RESULTS: In the lowest VAT tertile, risk factor prevalence was low, although systolic blood pressure in women and rates of high triglycerides, impaired fasting glucose, hypertension, and the metabolic syndrome in men increased with increasing SAT tertile (all P < 0.04). In contrast, in the top VAT tertile, lower triglycerides were observed in men with increasing SAT (64.4% high triglycerides in SAT tertile 1 vs. 52.7% in SAT tertile 3, P = 0.03). Similar observations were made for women, although results were not statistically significant (50.6% high triglycerides in SAT tertile 1 vs. 41.0% in tertile 3, P = 0.10). Results in the highest VAT tertile were notable for a lack of increase in the prevalence of low HDL in men and women and in rates of impaired fasting glucose in men with increasing subcutaneous fat, despite sizable differences in BMI across SAT tertiles (27.1 to 36.3 kg/m(2)[women]; 28.1 to 35.7 kg/m(2)[men]). CONCLUSIONS: Although adiposity increases the absolute risk of metabolic and cardiovascular disease, abdominal subcutaneous fat is not associated with a linear increase in the prevalence of all risk factors among the obese, most notably, high triglycerides.

Heat injury to cells in perfused systems.

Tissue injury in response to excessive heat results in a clinical burn. Burns cause a range of physiologic derangements, including denaturation of macromolecular structures, leakage of cell membranes, activation of cytokines, and cessation of blood flow, all leading to tissue death. The purpose of this paper is to examine the mechanisms and consequences of burn injury and to discuss potential therapies based on these mechanisms. Knowledge of the thermal properties of tissues can predict the time-temperature relationship necessary to cause a specified thermal insult. Changes in cell membrane biochemistry and the stabilization of proteins through the heat-shock response can enable biomacromolecules to withstand supraphysiological temperatures. Mechanisms of cellular repair allow recovery of cellular function after thermal insult. An understanding of the response of proteins, cellular organelles, and cells to heat provides the foundation for understanding the pathophysiology and treatment of burn injury. The physics, biochemistry, and cellular biology behind the host response to thermal injury in perfused systems are reviewed.

Subluxation of transscleral sutured posterior chamber intraocular lens (TSIOL).

PURPOSE: To evaluate factors related to late-onset transscleral sutured posterior chamber intraocular lens (TSIOL) subluxation. METHODS: Retrospective observational case series. Analysis of subluxated TSIOLs in seven eyes from seven patients treated between May 1999 and May 2001. RESULTS: Mean age at the time of TSIOL surgery was 33 +/- 6 years. Mean time from TSIOL surgery to its subluxation was 78 +/- 19 months. Initial diagnoses requiring TSIOL surgeries were previous history of trauma and Marfan syndrome. Subluxation of TSIOLs was associated with blunt trauma in three eyes, whereas the other four eyes experienced spontaneous lens dislocation. CONCLUSION: Subluxation of TSIOL is not uncommon in younger patients with history of trauma or Marfan syndrome.