Bipedal locomotion in zoo apes: Revisiting the hylobatian model for bipedal origins.

Bipedal locomotion is a hallmark of being human. Yet the body form from which bipedalism evolved remains unclear. Specifically, the positional behaviour (i.e. orthograde vs. pronograde) and the length of the lumbar spine (i.e. long and mobile vs. short and stiff) of the last common ancestor (LCA) of the African great apes and humans require further investigation. While fossil evidence would be the most conclusive, the paucity of hominid fossils from 5-10 million years ago makes this field of research challenging. In their absence, extant primate anatomy and behaviour may offer some insight into the ancestral body form from which bipedalism could most easily evolve. Here, we quantify the frequency of bipedalism in a large sample (N = 496) of zoo-housed hominoids and cercopithecines. Our results show that while each studied species of ape and monkey can move bipedally, hylobatids are significantly more bipedal and engage in bipedal locomotion more frequently and for greater distances than any other primate sampled. These data support hypotheses of an orthograde, long-backed and arboreal LCA, which is consistent with hominoid fossils from the middle-to-late Miocene. If true, knuckle-walking evolved in parallel in Pan and Gorilla, and the human body form, particularly the long lower back and orthograde posture, is conserved.

Who is there? Captive western gorillas distinguish human voices based on familiarity and nature of previous interactions.

The ability to recognize conspecifics by their acoustic signals is of crucial importance to social animals, especially where visibility is limited, because it allows for discrimination between familiar and unfamiliar individuals and facilitates associations with and the avoidance of particular conspecifics. Animals may also benefit from an ability to recognize and use the information coded into the auditory signals of other species. Companion species such as dogs, cats, and horses are able to discriminate between familiar and unfamiliar human voices; however, whether this ability is widespread across vertebrates is still unknown. Using playback experiments, we tested whether western gorillas living at Zoo Atlanta were able to discriminate between the voices of subgroups of people: i.e., unfamiliar individuals, familiar individuals with whom the gorillas had positive interactions, and familiar individuals with whom they had negative interactions. Gorillas responded significantly more often (longer gazing duration, higher gazing frequency, shorter latency, and larger number of distress behaviors) to the voices of unfamiliar and familiar-negative individuals than to those of familiar-positive individuals, indicating that they recognized the voices of subgroup of people based on familiarity and possibly the nature of the relationship with them. Future studies should determine whether this is also the case in the wild, where interspecific associations with humans are less intense than they are in captive settings.

Isotopic and elemental corroborates for wild bearded capuchin (Sapajus libidinosus) omnivorous dietary adaptation at Fazenda Boa Vista, Brazil.

RATIONALE: This study analyzes variability in the diets of wild bearded capuchin monkeys, Sapajus libidinosus, by analyzing stable carbon (δ13 C) and nitrogen (δ15 N) isotope ratios and elemental concentrations (%C and %N) of fecal samples and food items. Developing isotopic and elemental correlates for diets of habituated subjects is a necessary step towards applying similar methods to interpret diets of unhabituated or cryptic subjects. METHODS: Fecal samples from wild capuchins and their foods were collected at Fazenda Boa Vista, Brazil. Fecal samples from laboratory-housed Sapajus spp. and their foods were analyzed to establish diet-feces offsets for δ13 C, δ15 N, %C, and %N. Samples were dried, powdered, and measured for isotopic and elemental values. A Bayesian mixing model commutes isotopic and elemental data from wild capuchins into likely proportions of different food categories. RESULTS: The captive study shows small diet-feces spaces for Sapajus spp. of -0.8 ± 0.7‰ for δ13 C, -0.2 ± 0.4‰ for δ15 N, -6.1 ± 1.7% for %C, and -1.0 ± 0.6% for %N. The wild study shows omnivorous diets based on C3 , C4 , and CAM plants, and fauna. Subject diets are highly varied within and between days. Fecal data show age-related differences in diet and crop-raiding. There is no consistent isotopic or elemental difference between mothers and infants. CONCLUSIONS: Fecal stable isotope and elemental evidence employed in a Bayesian mixing model reflects the highly varied diets of capuchin monkeys in an isotopically heterogeneous environment. The isotopic and elemental variability reported here will aid similar diet reconstructions among unhabituated subjects in the future, but precludes tracking weaning isotopically among capuchins in this environment.

Compound grips in tufted capuchin monkeys (Sapajus spp and Sapajus libidinosus).

An experimental study with captive individuals and study of video recordings of wild monkeys explored whether and how tufted capuchin monkeys use onehand to hold one or more objects with multiple grips (compound grips). A task designed to elicit compound grip was presented to five captive tufted capuchin monkeys (Sapajus spp). The monkeys held one to four balls in onehand and dropped the balls individually into a vertical tube. Multiple simple grips and independent digit movements enabled separate control of multiple objects in one hand. Monkeys always supported the wrist on the horizontal edge of the tube before releasing the ball. Increasing the number of balls decreased the likelihood that the monkeys managed the task. Wild bearded capuchins (Sapajus libidinosus) used compound grips spontaneously to store multiple food items. Compound grips have been described in macaques, gorillas, chimpanzees, and humans, and now in a New World primate. We predict that any primate species that exhibits precision grips and independent digit movement can perform compound grips. Our findings suggest many aspects of compound grip that await investigation.

Treatment patterns for ductal carcinoma in situ with close or positive mastectomy margins.

BACKGROUND: Mastectomy remains an effective treatment for ductal carcinoma in situ (DCIS) but whether further therapy is warranted for close or positive margins is controversial. We aim to characterize the treatment practices of DCIS throughout the United States in patients who undergo mastectomy with close or positive margins to better understand the use of postmastectomy radiation therapy (PMRT). MATERIALS AND METHODS: Using the 2004-2013 National Cancer Database, we identified all female patients with a diagnosis of DCIS who underwent mastectomy. Distributional characteristics were summarized for overall and margin-stratified samples. Characteristic differences were assessed by region and receipt of radiation. Chi-square and independent sample t-tests were used to assess differences for categorical and continuous variables, respectively. RESULTS: In 21,591 patients who met inclusion criteria, 470 patients with close/positive margins were identified. Sixteen percent of patients with close/positive margins received PMRT compared to 1.5% with negative margins (P < 0.01). There was no difference in PMRT and patient race, insurance status, treatment facility, or endocrine therapy. Patients with close/positive margins who received PMRT were more likely to be in an urban setting from the Midwest (24.6%) and Northeast (21.8%) compared to the West (11.0%) and South (10.7%) (P < 0.01). CONCLUSIONS: Use of PMRT for DCIS following mastectomy with close/positive margins differs across the country. Regional variations in treatment patterns reinforce a need to determine whether PMRT improves survival to establish treatment guidelines.

Association Between Preoperative Proteinuria and Postoperative Acute Kidney Injury and Readmission.

Importance: Proteinuria indicates renal dysfunction and is a risk factor for morbidity among medical patients, but less is understood among surgical populations. There is a paucity of studies investigating how preoperative proteinuria is associated with surgical outcomes, including postoperative acute kidney injury (AKI) and readmission. Objective: To assess preoperative urine protein levels as a biomarker for adverse surgical outcomes. Design, Setting, and Participants: A retrospective, population-based study was conducted in a cohort of patients with and without known preoperative renal dysfunction undergoing elective inpatient surgery performed at 119 Veterans Affairs facilities from October 1, 2007, to September 30, 2014. Data analysis was conducted from April 4 to December 1, 2016. Preoperative dialysis, septic, cardiac, ophthalmology, transplantation, and urologic cases were excluded. Exposures: Preoperative proteinuria as assessed by urinalysis using the closest value within 6 months of surgery: negative (0 mg/dL), trace (15-29 mg/dL), 1+ (30-100 mg/dL), 2+ (101-300 mg/dL), 3+ (301-1000 mg/dL), and 4+ (>1000 mg/dL). Main Outcomes and Measures: Primary outcome was postoperative predischarge AKI and 30-day postdischarge unplanned readmission. Secondary outcomes included any 30-day postoperative outcome. Results: Of 346 676 surgeries, 153 767 met inclusion criteria, with the majority including orthopedic (37%), general (29%), and vascular procedures (14%). Evidence of proteinuria was shown in 43.8% of the population (trace: 20.6%, 1+: 16.0%, 2+: 5.5%, 3+: 1.6%) with 20.4%, 14.9%, 4.3%, and 0.9%, respectively, of the patients having a normal preoperative estimated glomerular filtration rate (eGFR). In unadjusted analysis, preoperative proteinuria was significantly associated with postoperative AKI (negative: 8.6%, trace: 12%, 1+: 14.5%, 2+: 21.2%, 3+: 27.6%; P < .001) and readmission (9.3%, 11.3%, 13.3%, 15.8%, 17.5%, respectively, P < .001). After adjustment, preoperative proteinuria was associated with postoperative AKI in a dose-dependent relationship (trace: odds ratio [OR], 1.2; 95% CI, 1.1-1.3, to 3+: OR, 2.0; 95% CI, 1.8-2.2) and 30-day unplanned readmission (trace: OR, 1.0; 95% CI, 1.0-1.1, to 3+: OR, 1.3; 95% CI, 1.1-1.4). Preoperative proteinuria was associated with AKI independent of eGFR. Conclusions and Relevance: Proteinuria was associated with postoperative AKI and 30-day unplanned readmission independent of preoperative eGFR. Simple urine assessment for proteinuria may identify patients at higher risk of AKI and readmission to guide perioperative management.

Association Between Preoperative Hemoglobin A1c Levels, Postoperative Hyperglycemia, and Readmissions Following Gastrointestinal Surgery.

IMPORTANCE: Preoperative hyperglycemia is associated with adverse postoperative outcomes among patients who undergo surgery. Whether preoperative hemoglobin A1c (HbA1c) or postoperative glucose levels are more useful in predicting adverse events following surgery is uncertain in the current literature. OBJECTIVE: To examine the use of preoperative HbA1c and early postoperative glucose levels for predicting postoperative complications and readmission. DESIGN, SETTING, AND PARTICIPANTS: In this observational cohort study, inpatient gastrointestinal surgical procedures performed at 117 Veterans Affairs hospitals from 2007 to 2014 were identified, and cases of known infection within 3 days before surgery were excluded. Preoperative HbA1c levels were examined as a continuous and categorical variable (<5.7%, 5.7%-6.5%, and >6.5%). A logistic regression modeled postoperative complications and readmissions with the closest preoperative HbA1c within 90 days and the highest postoperative glucose levels within 48 hours of undergoing surgery. MAIN OUTCOMES AND MEASURES: Postoperative complications and 30-day unplanned readmission following discharge. RESULTS: Of 21 541 participants, 1193 (5.5%) were women, and the mean (SD) age was 63.7 (10.6) years. The cohort included 23 094 operations with measurements of preoperative HbA1c levels and postoperative glucose levels. The complication and 30-day readmission rates were 27.2% and 14.7%, respectively. In logistic regression models adjusting for HbA1c, postoperative glucose levels, postoperative insulin use, diabetes, body mass index (calculated as weight in kilograms divided by height in meters squared), and other patient and procedural factors, peak postoperative glucose levels of more than 250 mg/dL were associated with increased 30-day readmissions (odds ratio, 1.18; 95% CI, 0.99-1.41; P = .07). By contrast, a preoperative HbA1c of more than 6.5% was associated with decreased 30-day readmissions (odds ratio, 0.85; 95% CI, 0.74-0.96; P = .01). As preoperative HbA1c increased, the frequency of 48-hour postoperative glucose checks increased (4.92, 6.89, and 9.71 for an HbA1c <5.7%, 5.7%-6.4%, and >6.5%, respectively; P < .001). Patients with a preoperative HbA1c of more than 6.5% had lower thresholds for postoperative insulin use. CONCLUSIONS AND RELEVANCE: Early postoperative hyperglycemia was associated with increased readmission, but elevated preoperative HbA1c was not. A higher preoperative HbA1c was associated with increased postoperative glucose level checks and insulin use, suggesting that heightened postoperative vigilance and a lower threshold to treat hyperglycemia may explain this finding.

Association of the Modified Frailty Index With 30-Day Surgical Readmission.

IMPORTANCE: Frail patients are known to have poor perioperative outcomes. There is a paucity of literature investigating how the Modified Frailty Index (mFI), a validated measure of frailty, is associated with unplanned readmission among military veterans following surgery. OBJECTIVE: To understand the association between frailty and 30-day postoperative unplanned readmission. DESIGN, SETTING, AND PARTICIPANTS: A retrospective cohort study was conducted among adult patients who underwent surgery and were discharged alive from Veterans Affairs hospitals for orthopedic, general, and vascular conditions between October 1, 2007, and September 30, 2014, with a postoperative length of stay between 2 and 30 days. EXPOSURE: Frailty, as calculated by the 11 variables on the mFI. MAIN OUTCOMES AND MEASURES: The primary outcome of interest is 30-day unplanned readmission. Secondary outcomes included any 30-day predischarge or postdischarge complication, 30-day postdischarge mortality, and 30-day emergency department visit. RESULTS: The study sample included 236 957 surgical procedures (among 223 877 men and 13 080 women; mean [SD] age, 64.0 [11.3] years) from high-volume surgical specialties: 101 348 procedures (42.8%) in orthopedic surgery, 92 808 procedures (39.2%) in general surgery, and 42 801 procedures (18.1%) in vascular surgery. The mFI was associated with readmission (odds ratio [OR], 1.11; 95% CI, 1.10-1.12; R2 = 10.3%; C statistic, 0.71). Unadjusted rates of overall 30-day readmission (26 262 [11.1%]), postdischarge emergency department visit (34 204 [14.4%]), any predischarge (13 855 [5.9%]) or postdischarge (14 836 [6.3%]) complication, and postdischarge mortality (1985 [0.8%]) varied by frailty in a dose-dependent fashion. In analysis by individual mFI components using Harrell ranking, impaired functional status, identified as nonindependent functional status (OR, 1.16; 95% CI, 1.11-1.21; P < .01) or having a residual deficit from a prior cerebrovascular accident (OR, 1.17; 95% CI, 1.11-1.22; P < .01), contributed most to the ability of the mFI to anticipate readmission compared with the other components. Acutely impaired sensorium (OR, 1.12; 95% CI, 0.99-1.27; P = .08) and history of a myocardial infarction within 6 months (OR, 0.93; 95% CI, 0.81-1.06; P = .28) were not significantly associated with readmission. CONCLUSIONS AND RELEVANCE: The mFI is associated with poor surgical outcomes, including readmission, primarily due to impaired functional status. Targeting potentially modifiable aspects of frailty preoperatively, such as improving functional status, may improve perioperative outcomes and decrease readmissions.

Venous thromboembolic events: How low can you go?

BACKGROUND: We evaluated postoperative venous thromboembolism (VTE) chemical prophylaxis adherence to assess the preventability of VTEs. METHODS: A case-control study was performed using the 2011-2015 ACS-NSQIP single institution database. Cases were identified as patients who experienced postoperative VTE within 30 days following surgery. Controls were matched 2:1 on procedure, age, and BMI. Association between inpatient chemical prophylaxis adherence and postoperative VTE was evaluated with conditional logistic regression. RESULTS: Seventy-three cases were matched to 145 controls. Complete inpatient VTE chemical prophylaxis adherence did not differ between cases and controls (45.2% vs. 46.2%, p = 1.00). Odds of postoperative VTE increased if a patient's prophylaxis was interrupted (OR 6.34, 95% CI 1.82-22.13). However, 53.7% of instances of interrupted prophylaxis were medically justified by concern for bleeding, spine operation, or for additional upcoming procedure. CONCLUSIONS: Nearly half of patients who experienced postoperative VTEs received appropriate guideline-driven care. Most interruptions in chemical prophylaxis were justified medically. This further questions the preventability of postoperative VTEs and the utility of this outcome as a valid measure of hospital quality.

Transitional care interventions and hospital readmissions in surgical populations: a systematic review.

BACKGROUND: Despite hospital readmission being a targeted quality metric, few studies have focused on the surgical patient population. We performed a systematic review of transitional care interventions and their effect on hospital readmissions after surgery. DATA SOURCES: PubMed was searched for studies evaluating transitional care interventions in surgical populations within the years 1995 to 2015. Of 3,527 abstracts identified, 3 randomized controlled trials and 7 observational cohort studies met inclusion criteria. CONCLUSIONS: Discharge planning programs reduced readmissions by 11.5% (P = .001), 12.5% (P = .04), and 23% (P = .26). Patient education interventions reduced readmissions by 14% (P = .28) and 23.5% (P < .05). Primary care follow-up reduced readmissions by 8.3% for patients after high-risk surgeries (P < .001). Home visits reduced readmissions by 7.69% (P = .023) and 4% (P = .161), respectively. Therefore, improving discharge planning, patient education, and follow-up communication may reduce readmissions.

Postoperative 30-day Readmission: Time to Focus on What Happens Outside the Hospital.

OBJECTIVE: The aim of this study is to understand the relative contribution of preoperative patient factors, operative characteristics, and postoperative hospital course on 30-day postoperative readmissions. BACKGROUND: Determining the risk of readmission after surgery is difficult. Understanding the most important contributing factors is important to improving prediction of and reducing postoperative readmission risk. METHODS: National Veterans Affairs Surgical Quality Improvement Program data on inpatient general, vascular, and orthopedic surgery from 2008 to 2014 were merged with laboratory, vital signs, prior healthcare utilization, and postoperative complications data. Variables were categorized as preoperative, operative, postoperative/predischarge, and postdischarge. Logistic models predicting 30-day readmission were compared using adjusted R and c-statistics with cross-validation to estimate predictive discrimination. RESULTS: Our study sample included 237,441 surgeries: 43% orthopedic, 39% general, and 18% vascular. Overall 30-day unplanned readmission rate was 11.1%, differing by surgical specialty (vascular 15.4%, general 12.9%, and orthopedic 7.6%, P < 0.001). Most common readmission reasons were wound complications (30.7%), gastrointestinal (16.1%), bleeding (4.9%), and fluid/electrolyte (7.5%) complications. Models using information available at the time of discharge explained 10.4% of the variability in readmissions. Of these, preoperative patient-level factors contributed the most to predictive models (R 7.0% [c-statistic 0.67]); prediction was improved by inclusion of intraoperative (R 9.0%, c-statistic 0.69) and postoperative variables (R 10.4%, c-statistic 0.71). Including postdischarge complications improved predictive ability, explaining 19.6% of the variation (R 19.6%, c-statistic 0.76). CONCLUSIONS: Postoperative readmissions are difficult to predict at the time of discharge, and of information available at that time, preoperative factors are the most important.

Readmission rates after lower extremity bypass vary significantly by surgical indication.

OBJECTIVE: Readmission rates after vascular surgery are among the highest within surgical specialties, and lower extremity bypass has the highest readmission rate of vascular surgery procedures. We analyzed how 30-day readmissions and risk factors for readmissions vary by indication for lower extremity bypass. METHODS: We queried the 2012-2014 American College of Surgeons National Surgical Quality Improvement Program procedure-targeted vascular cohort to identify all patients who underwent lower extremity bypass. Emergent procedures and planned readmissions were excluded. Patients were stratified by surgical indication: claudication, critical limb ischemia rest pain (CLI RP), critical limb ischemia tissue loss (CLI TL), and other. The χ2 and Wilcoxon rank sum tests were used to test the differences between categorical and continuous variables, respectively. Logistic regression was used to estimate odds ratios for predictors of readmission adjusted for preoperative factors that were selected a priori. RESULTS: The overall 30-day readmission rate among the 6112 patients who underwent lower extremity bypass was 14.8%. Readmission rates varied significantly on the basis of the indication for surgery. In unadjusted comparisons, 18.8% of patients with CLI TL were readmitted compared with 16.5% with CLI RP, 9.4% with claudication, and 8.2% with other indications (P < .001). After adjustment for preoperative factors, 30-day readmissions were higher for patients with CLI TL (odds ratio, 1.67; 95% confidence interval, 1.35-2.06) and CLI RP (odds ratio, 1.70; 95% confidence interval, 1.38-2.09) compared with patients with claudication. CONCLUSIONS: The 30-day readmission rates after lower extremity bypass vary significantly by surgical indication. Because lower extremity bypasses are performed for multiple indications, if readmission rates are publically reported and hospitals can be penalized for higher than expected readmission rates, the expected readmission rates should be adjusted for surgical indication.

Evaluation of environmental scanning electron microscopy for analysis of Proteus mirabilis crystalline biofilms in situ on urinary catheters.

Proteus mirabilis is a common cause of catheter-associated urinary tract infections and frequently leads to blockage of catheters due to crystalline biofilm formation. Scanning electron microscopy (SEM) has proven to be a valuable tool in the study of these unusual biofilms, but entails laborious sample preparation that can introduce artefacts, undermining the investigation of biofilm development. In contrast, environmental scanning electron microscopy (ESEM) permits imaging of unprocessed, fully hydrated samples, which may provide much insight into the development of P. mirabilis biofilms. Here, we evaluate the utility of ESEM for the study of P. mirabilis crystalline biofilms in situ, on urinary catheters. In doing so, we compare this to commonly used conventional SEM approaches for sample preparation and imaging. Overall, ESEM provided excellent resolution of biofilms formed on urinary catheters and revealed structures not observed in standard SEM imaging or previously described in other studies of these biofilms. In addition, we show that energy-dispersive X-ray spectroscopy (EDS) may be employed in conjunction with ESEM to provide information regarding the elemental composition of crystalline structures and demonstrate the potential for ESEM in combination with EDS to constitute a useful tool in exploring the mechanisms underpinning crystalline biofilm formation.