Food impaction: etiology over 35 years and association with eosinophilic esophagitis.

With the emergence of eosinophilic esophagitis (EoE) as a common cause of food impaction (FI) and a presumed increase in incidence of EoE in the population, the effect on the incidence of FI has not been well described. The aim of this study is to describe the incidence of FI and endoscopic findings in these patients and the association with EoE. A population-based retrospective chart review of the Rochester Epidemiology Project database was performed to identify all patients within Olmsted County that presented with FI from 1976 to 2012. A review of all endoscopic findings, biopsy results, and demographic data was performed. 497 patients were identified with FI from 1976 to 2012. The overall incidence of FI has changed from 1976 to 2012 (Fig. 1) (P < 0.001). The peak incidence of 17.12 per 100,000 people occurred in the time period 1995 to 2000. Both the incidence of comorbid gastroesophageal reflux disease (GERD) and proton pump inhibitor (PPI) use increased over the time period of the study (P < 0.001 for both). Of these patients, 188 (46.7%) had no abnormalities on their endoscopy. The most common endoscopic finding was stricture in 71 (17.6%) patients followed closely by Schatzki's ring in 68 (16.9%) patients. 139 patients had biopsies performed within 2 years of FI and 50 (36.0%) of those were diagnosed with EoE. We present for the first time the changing incidence of FI over the last 35 years in a population-based setting. We also demonstrate the rise of EoE as an important clinical consideration in patients with FI.

Pharmacokinetics of ceftiofur sodium in equine pregnancy.

Eleven pregnant pony mares (D270-326) were administered ceftiofur sodium intramuscularly at 2.2 mg/kg (n = 6) or 4.4 mg/kg (n = 5), once daily. Plasma was obtained prior to ceftiofur administration and at 0.5, 1, 2, 4, 8, 12, and 24 hr after administration. Eight pony mares were re-enrolled in the study at least 3 days from expected foaling to ensure steady-state concentrations of drug at the time of foaling. Mares were administered ceftiofur sodium (4.4 mg/kg, IM) daily until foaling. Parturition was induced using oxytocin 1 hr after ceftiofur sodium administration. Allantoic and amniotic fluid, plasma, and colostrum samples were collected at time of foaling. Serial foal plasma samples were obtained. Placental tissues were collected. Desfuroylceftiofur acetamide (DCA) concentrations were measured in samples by high-performance liquid chromatography (HPLC). Mean (±SD) peak serum concentrations of DCA were 3.97 ± 0.50 µg/ml (low dose) and 7.45 ± 1.05 µg/ml (high dose). Terminal half-life was significantly (p = .014) shorter after administration of the low dose (2.91 ± 0.59 hr) than after administration of the high dose (4.10 ± 0.72 hr). The mean serum concentration of DCA from mares at time of foaling was 7.96 ± 1.39 µg/ml. The mean DCA concentration in colostrum was 1.39 ± 0.70 µg/ml. DCA concentrations in allantoic fluid, amniotic fluid, placental tissues, and foal plasma were below the limit of quantification (<0.1 µg/ml) and below the minimum inhibitory concentration of ceftiofur against relevant pathogens. These results infer incomplete passage of DCA across fetal membranes after administration of ceftiofur sodium to normal pony mares.

Daily salivary cortisol patterns in midlife women with hot flashes.

OBJECTIVE: Diurnal salivary cortisol patterns in healthy adults are well established but have not been studied in midlife women with hot flashes. We hypothesized that frequent hot flashes are associated with aberrant cortisol patterns similar to sleep-deficient individuals. DESIGN: Cross-sectional. PARTICIPANTS: A total of 306 women, ages 40-62, randomized to a behavioural intervention for hot flashes. MEASUREMENTS: Baseline comparisons of cortisol geometric means (nmol/l) from four daily time points averaged over two consecutive days plus other calculated cortisol measures were made between groups defined by baseline: (i) mean daily hot flash frequency tertile (≤5·5, N = 103; >5·5-8·8, N = 103; >8·8, N = 100) and (ii) selected characteristics. Repeated-measures linear regression models of log-transformed cortisol evaluated group differences, adjusting for covariates. RESULTS: Women were 67% White and 24% African American, with 7·6 (SD 3·9) hot flashes per day. Salivary cortisol geometric means (nmol/l) among all women were as follows: 75·0 (SD 44·8) total, 8·6 (SD 5·6) wake, 10·0 (SD 7·5) wake +30 min, 3·7 (SD 3·3) early afternoon and 1·6 (SD 1·8) bedtime. Wake + 30-minute values showed an 18% median rise from wake values (interquartile range -24 to 96%), and means varied by hot flash frequency tertile, from lowest to highest: 11·4(SD 7·3), 10·3 (SD 6·5) and 8·6 (SD 7·8), respectively, P = 0·003. Beside the early afternoon value (P = 0·02), cortisol values did not vary by hot flash frequency. CONCLUSION: Taken together, these findings suggest that high frequency of moderate-to-severe hot flashes may be associated with subtle abnormalities in cortisol concentrations - a pattern consistent with chronic sleep disturbance.

The cost of feeding bred dairy heifers on native warm-season grasses and harvested feedstuffs.

Heifer rearing is one of the largest production expenses for dairy cattle operations, which is one reason milking operations outsource heifer rearing to custom developers. The cost of harvested feedstuffs is a major expense in heifer rearing. A possible way to lower feed costs is to graze dairy heifers, but little research exists on this topic in the mid-south United States. The objectives of this research were to determine the cost of feeding bred dairy heifers grazing native warm-season grasses (NWSG), with and without legumes, and compare the cost of grazing with the cost of rearing heifers using 3 traditional rations. The 3 rations were corn silage with soybean meal, corn silage with dry distillers grain, and a wet distillers grain-based ration. Bred Holstein heifers between 15- and 20-mo-old continuously grazed switchgrass (SG), SG with red clover (SG+RC), a big bluestem and Indiangrass mixture (BBIG), and BBIG with red clover (BBIG+RC) in Tennessee during the summer months. Total grazing days were calculated for each NWSG to determine the average cost/animal per grazing day. The average daily gain (ADG) was calculated for each NWSG to develop 3 harvested feed rations that would result in the same ADG over the same number of grazing day as each NWSG treatment. The average cost/animal per grazing day was lowest for SG ($0.48/animal/grazing d) and highest for BBIG+RC ($1.10/animal/grazing d). For both BBIG and SG, legumes increased the average cost/animal per grazing day because grazing days did not increase enough to account for the additional cost of the legumes. No difference was observed in ADG for heifers grazing BBIG (0.85 kg/d) and BBIG+RC (0.94 kg/d), and no difference was observed in ADG for heifers grazing SG (0.71 kg/d) and SG+RC (0.70 kg/d). However, the ADG for heifers grazing SG and SG+RC was lower than the ADG for heifers grazing either BBIG or BBIG+RC. The average cost/animal per grazing day was lower for all NWSG treatments than the average cost/animal per day for all comparable feed rations at a low, average, and high yardage fee. Results of this study suggest that SG was the most cost-effective NWSG alternative to harvested feeds for bred dairy heifer rearing.

Effect of 2 corpora lutea on blood perfusion, peripheral progesterone, and hepatic steroid-inactivating enzymes in dairy cattle.

The luteal structure that develops postovulation is critical to the facilitation and maintenance of pregnancy in dairy cattle. The objectives of this experiment were to determine if the induction of an accessory corpus luteum (CL), via human chorionic gonadotropin, altered blood perfusion of CL, peripheral concentrations of progesterone, or hepatic steroid-inactivating enzymes. Twenty-eight late-lactation Holstein cows were synchronized using the Ovsynch protocol and randomly assigned to 1 of 2 treatment groups. Cows received either an injection of human chorionic gonadotropin (1,000IU, i.m.) to induce an accessory CL (cows had exactly 2CL in 1 ovary) or no treatment (cows had exactly 1CL). Corpora lutea were examined daily from d 10 to 18 (d 0 was induced ovulation) via Doppler ultrasonography and a blood sample was collected. Volume of the CL was recorded, as well as images and videos of each CL, which were analyzed for blood perfusion. On d 13, a liver biopsy was performed to analyze hepatic steroid-inactivating enzymes. Cows with 1 or 2CL had similar peripheral concentrations of progesterone. Cows with 2CL had similar luteal volumes to cows with 1CL but cows with 2CL had greater total luteal blood perfusion. Hepatic enzyme [cytochrome P450 (CYP) 1A, 3A, and 2C, aldo-keto reductase 1C, and uridine diphosphate glucuronosyltransferase] activities did not differ between cows with 1 and 2CL. Overall, the observed increase in total luteal blood perfusion in cows with 2CL did not correspond to differences in peripheral concentrations of progesterone or clearance of progesterone measured by the hepatic enzyme activity. This could indicate that induction of an accessory CL would not affect concentrations of progesterone necessary to maintain pregnancy.

The structure of the cerebral cortex across adult life: age-related patterns of surface area, thickness, and gyrification.

Older adults exhibit global reductions in cortical surface area, but little is known about the regional patterns of reductions or how these relate to other measures of brain structure. This knowledge is critical to understanding the dynamic relationship between different macrostructural properties of the cortex throughout adult life. Here, cortical arealization, local gyrification index (LGI), and cortical thickness were measured vertex wise across the brain surface in 322 healthy adults (20-85 years), with the aims of 1) characterizing age patterns of the three separate cortical measures and 2) testing the age-independent relationships among cortical surface area, gyrification, and thickness. Surface area showed strong age-related decreases, particularly pronounced in dorsomedial prefrontal, lateral temporal, and fusiform cortices, independently of total white matter volume. LGI decreased with age independently of regional surface area, with strongest effects laterally, extending from the angular gyrus in all directions. As expected, regional surface area and LGI were positively related. However, both measures correlated negatively with thickness, indicating increasing local arealization and gyrification with decreasing cortical thickness. We suggest that this pattern of regional "cortical stretching" reflects the well-established phylogenetic principle of maximizing surface area and gyrification rather than increase thickness to facilitate brain connectivity and functional development.

Dependence of ß3-adrenergic signaling on the adipokine leptin in cardiac myocytes.

ß3-Adrenergic receptors (ß3ARs) negatively regulate ß-adrenergic signaling via nitric oxide and are dependent on the adipokine leptin for normal expression in adipocytes, thus making ß3AR an attractive candidate for cross-talk with leptin in the heart. Accordingly, we tested the hypothesis that cardiac ß3AR expression and function are dependent on leptin and are severely diminished in leptin-deficient ob/ob mice. Using isolated cardiac myocyte physiology studies, we found that ß3AR function was significantly diminished in ob/ob myocytes and in wild-type myocytes treated with leptin antagonist. This finding was supported by quantitative PCR demonstrating markedly decreased ß3AR mRNA levels in ob/ob mice. Both ß3AR mRNA and function were restored in ob/ob mice after in vivo leptin repletion. We propose that diminished ß3AR signaling may be the critical element to explain the direct effects of leptin on the myocardium and suggest that this work reveals a key feature in the role of leptin in obesity-related cardiac hypertrophy and heart failure.

Autologous inferior dermal sling (autoderm) with concomitant skin-envelope reduction mastectomy: an excellent surgical choice for women with macromastia and clinically significant ptosis.

BACKGROUND: Skin-sparing mastectomy and prosthetic reconstruction can be complicated by poor surgical outcomes in large-breasted, obese women. This article describes a single surgeon's experience comparing conventional skin-sparing mastectomy (SSM) and skin-reduction mastectomy using an autologous vascularized inferior dermal/cutaneous sling (autoderm). METHODS: From July 2007 to May 2012, patients undergoing skin-sparing mastectomy were evaluated for surgical outcomes. After July 2009, the surgeon performed skin-reduction mastectomies with autoderm (SRM-AD) on all patients with macromastia or grade 3-4 ptosis. Remaining patients in this time period (SSM-cont) underwent conventional skin-sparing mastectomies while all previous patients (historical) also underwent skin-sparing mastectomies (SSM-hist). A predictive model was used to compare the large historical patients (who would have had reduction mastectomy if available) with the smaller historical patients to evaluate the effect of the procedure. RESULTS: Body mass index (BMI) and specimen weight were higher in both the SRM group and large historical group. The hazard ratio for having skin-reduction mastectomy was 0.53 (P = 0.51) compared with the historical group. There was a total of 16 complications for the whole study. Smoking was the only significant risk factor. CONCLUSIONS: This study shows that mastectomy with prosthetic reconstruction using a skin-reduction technique with autoderm can be done safely with a low complication rate and improved cosmetic outcomes in the traditionally "at-risk" group of women with high BMI and large ptotic breasts.

A query for effective mean particle size in dry and high-moisture corns.

The objective of this study was to investigate whether prediction of fermentation potential (FP) of dry and high-moisture (HM) corns could be improved by using a concept of effective (e) mean particle size (MPS). A set of FP standards was created by processing a single lot of Reid Yellow Dent (RYD) corn to achieve MPS of 3,778, 2,786, 2,282, 1,808, 1,410, 806, 586, 378, 308, 226, and 105 µm. In vitro gas production of RYD standards was measured, and peak absolute rate (PAR) of gas production (mL/0.2 g of DM/h) was used to establish a standard relationship between PAR and MPS. To identify factors other than MPS affecting FP, the MPS and nutrient composition of 36 diverse samples of dry (n=18) and HM (n=18) corns were determined. Composition included dry matter (DM), crude protein, soluble crude protein, neutral detergent fiber, starch, NH3-N, prolamin protein, and fat. In vitro gas production of undried, unground dry and HM corns was measured, and PAR, time of peak absolute rate (h), maximum cumulative gas production (mL/0.2 g of DM), gas production fractional rate (h⁻¹), and lag (h) were determined. Nonlinear relationships between MPS, defined as the dependent variable, and PAR, as an independent variable, were used to identify FP deviations unexplained by MPS. When no variation in nutritional composition was present (RYD standards), the relationship between PAR and MPS was described by an exponential decay model [RYD_MPS=9,006 × e((-0.452 × PAR)); R²=0.96]. For diverse dry and HM corn populations, the variation in MPS explained by PAR was diminished (R²=0.50). To investigate factors that diminish the relationship between MPS and PAR in diverse corns, relative residual (rr) MPS was determined [rrMPS = (MPS - RYD_MPS)/MPS], where RYD_MPS was predicted from the PAR of diverse dry and HM corn. The rrMPS was most highly related to prolamin protein [rrMPS(dry)=0.58-0.15 × (prolamin protein, % of DM); R²=0.43] and NH3-N [rrMPS(HM)=0.21+0.08 × (NH3-N, % of total N); R²=0.46] for dry and HM corns, respectively. An eMPS was calculated as eMPS = MPS - MPS × rrMPS, where rrMPS was predicted from prolamin protein or NH3-N concentration in dry and HM corn, respectively. The natural logarithm of eMPS accounted for 84% of the variability in PAR and 53% of the variability in the fractional rate of gas production. Calculating eMPS by adjusting the MPS of dry corn for prolamin and HM corn for NH3-N concentration improved the assessment of industry corn FP.

Weight and body composition change over a six-week holiday period.

Change in weight and body composition was assessed over a six-week holiday period. Baseline testing occurred the Monday or Tuesday prior to Thanksgiving Day (November 24 or 25, 2008), and the post-holiday assessment was the Monday or Tuesday after New Year's Day (January 5 or 6, 2009). Thirteen men and 21 women ranging in age from 23-61 years completed the study. The majority of participants (24 of 34) perceived that they had gained weight, and four did gain ≥2 kg. However, despite some changes to dietary and exercise habits, on average there was no difference between pre-holiday weight (74.0±17.8 kg) and post-holiday weight (73.9±18.1 kg), nor between pre-holiday body fat percentage (25.4±9.0%) and post-holiday body fat percentage (25.4±8.9%). Despite a perception of substantial weight gain, body weight and body fat remained unchanged over a six-week holiday period.

The influence of context on hemispheric recruitment during metaphor processing.

Although the left hemisphere's prominence in language is well established, less emphasis has been placed on possible roles for the right hemisphere. Behavioral, patient, and neuroimaging research suggests that the right hemisphere may be involved in processing figurative language. Additionally, research has demonstrated that context can modify language processes and facilitate comprehension. Here we investigated how figurativeness and context influenced brain activation, with a specific interest in right hemisphere function. Previous work in our laboratory indicated that novel stimuli engaged right inferior frontal gyrus (IFG) and that both novel and familiar metaphors engaged right IFG and right temporal pole. The graded salience hypothesis proposes that context may lessen integration demands, increase the salience of metaphors, and thereby reduce right hemisphere recruitment for metaphors. In the present study, fMRI was used to investigate brain function, whereas participants read literal and metaphoric sentences that were preceded by either a congruent or an incongruent literal sentence. Consistent with prior research, all sentences engaged traditional left hemisphere regions. Differences between metaphors and literal sentences were observed, but only in the left hemisphere. In contrast, a main effect of congruence was found in the right IFG, the right temporal pole, and the dorsal medial pFC. Partially consistent with the graded salience hypothesis, our results highlight the strong influence of context on language, demonstrate the importance of the right hemisphere in discourse, and suggest that, in a wider discourse context, congruence has a greater influence on right hemisphere recruitment than figurativeness.

In utero gene transfer into the pulmonary epithelium.

In early gestation the internal surface of the lung is structurally simple and an ideal target for somatic gene transfer. The transfer of genes into the growing lung would be particularly useful in the prenatal correction of cystic fibrosis, which has devastating pulmonary complications. In addition, in utero gene therapy has the potential to immunotolerize the individual, and thereby to avoid the immune reactions now seen with the current generation of adenoviral vectors. We injected a replication-defective adenoviral vector containing the lacZ reporter gene (Ad5.CMVlacZ) into the amniotic fluid of rat pups on the 16th day of gestation. At 16 days of gestation, rat lungs are equivalent in maturity to those of a 22-week human fetus as their airways are lined with undifferentiated multipotential stem cells. The pups showed high-level reporter gene expression in their airways a week following birth (13 days following infection). The expression was maintained during a time when the lung volume increased approximately 20-fold, alveolarization occurred, and the epithelial cells differentiated. These data establish gene targeting of undifferentiated fetal cells as an effective means of gene therapy.

Evaluation of surface lead migration in pre-1950 homes: an on-site hand-held X-ray fluorescence spectroscopy study.

Lead-paint concentration on specific surfaces (walls, floors, windowsills, etc.) in pre-1950 homes was measured using a hand-held X-ray fluorescence (XRF) spectroscope. Surface lead was examined concomitantly using wipe sampling and XRF Lead was detected in all 147 samples via XRF; and of these, 29 ( 20%) revealed surface lead contamination via wipe sampling. Seventeen of the positive wipe samples were collected from surfaces with clear visible defects, while 12 samples were collected from surfaces with no visible defects. Curve fitting of surface to lead-paint concentrations generated empirical relationships that described the migration of lead from inner layers at locations with and without visible defects. Curve fitting indicated that lead migration was power-law dependent when surface defects were present and linear when no defects were visible. These correlations may assist surveyors in predicting lead migration to the surface from lead-paint concentration measured with a hand-held XRF instrument.

Impact of MELD on waitlist outcome of retransplant candidates.

Under the current allocation system for liver transplantation (LTx), primary and retransplantation (ReTx) are treated identically. The aims of this study were (1) to compare the risk of death between ReTx and primary LTx candidates at a given MELD score and (2) to gauge the impact of the MELD-based allocation system on the waitlist outcome of ReTx candidates. Based on data of all waitlist registrants in the United States between 2000 and 2006, unique adult patients with chronic liver disease were identified and followed forward to determine mortality within six months of registration. There were a total of 45,943 patients waitlisted for primary LTx and 2081 registered for ReTx. In the MELD era (n = 30,175), MELD was significantly higher among ReTx candidates than primary LTx candidates (median, 21 vs. 15). Within a range of MELD scores where most transplantation took place, mortality was comparable between ReTx and primary candidates after adjusting for MELD. The probability for LTx increased significantly following implementation of the MELD-based allocation in both types of candidates. We conclude that by and large, primary and ReTx candidates fare equitably under the current MELD-based allocation system, which has contributed to a significant increase in the probability of LTx.

Baseline serum estradiol and fracture reduction during treatment with hormone therapy: the Women's Health Initiative randomized trial.

INTRODUCTION: The purpose of the study was to test the hypothesis that the reduction in fractures with hormone therapy (HT) is greater in women with lower estradiol levels. METHODS: We conducted a nested case-control study within the Women's Health Initiative HT Trials. The sample included 231 hip fracture case-control pairs and a random sample of 519 all fracture case-control pairs. Cases and controls were matched for age, ethnicity, randomization date, fracture history, and hysterectomy status. Hormones were measured prior to randomization. Incident cases of fracture were identified over an average follow-up of 6.53 years. RESULTS: There was no evidence that the effect of HT on fracture differed by baseline estradiol (E2) or sex hormone binding globulin (SHBG). Across all quartiles of E2 and SHBG, women randomized to HT had about a 50% lower risk of fracture, including hip fracture, compared to placebo. CONCLUSION: The effect of HT on fracture reduction is independent of estradiol and SHBG levels.

Impact of insufficient admission vitamin D serum concentrations on sepsis incidence and clinical outcomes in patients with thermal injury.

INTRODUCTION: In burn patients, vitamin D has been studied primarily in the pediatric population and focused mainly on the correlation with bone marker measurements and incidence of fractures. There is an association between vitamin D deficiency and the development of sepsis in non-burn critically-ill patients. However, there is limited data on vitamin D concentrations and clinical outcomes in burn patients, such as sepsis. The objective of this study is to evaluate the impact of vitamin D concentrations on the incidence of sepsis in adult burn patients. METHODS: This was a retrospective cohort of patients 18 years of age and older admitted between February 1, 2016 and February 28, 2018 to an American Burn Association (ABA) verified burn center with diagnosis of burn injury. The primary endpoint was incidence of sepsis using the ABA 2007 Sepsis Consensus Criteria between patients with adequate vitamin D concentrations (25[OH]D > 20 ng/mL) and insufficient vitamin D (25[OH]D < 20 ng/mL) concentrations measured on admission. Descriptive statistics were used for baseline demographics. Univariate analysis was conducted using Chi-square, Fisher's exact test or Mann-Whitney U test, as appropriate. RESULTS: A total of 115 patients were screened and 107 patients were included in this study. Sixty three patients (58.9%) had insufficient vitamin D concentrations. Patient demographics were overall similar between groups. The median total body surface area burned was 14.6% in the insufficient vitamin D group, and 12.1% in the adequate vitamin D group (p = 0.2). There was a trend towards greater incidence of sepsis in the insufficient vitamin D group in the univariate analysis (15.9% vs. 4.5%, p = 0.07). The multivariable logistic regression analysis found that adequate vitamin D concentrations was associated with a reduction in the incidence of sepsis (OR 0.10, 95% CI 0.01-0.88). The insufficient vitamin D group had a longer median hospital LOS (19 [IQR 11-37] vs 11.5 [IQR 7-20] days, p < 0.05), longer intensive care unit LOS (17 [IQR 10-37] vs 5 [IQR 2-19.5] days, p < 0.05) and fewer ventilator free days (26 [IQR 18-28] vs 28 [IQR 27-28] days, p < 0.05). There was no difference in mortality between groups (p = 0.69). CONCLUSIONS: Patients with adequate vitamin D concentrations on admission had a reduction in the incidence of sepsis as compared to patients with insufficient vitamin D concentrations. Insufficient vitamin D concentrations may contribute to other worsened clinical outcomes in burn patients. Our findings set the stage for future, multicenter studies to determine the role of vitamin D supplementation in burn patients.

A Quantitative Analysis of Micrurus Coral Snakes Reveals Unexpected Variation in Stereotyped Anti-Predator Displays Within a Mimicry System.

Warning signals in chemically defended organisms are critical components of predator-prey interactions, often requiring multiple coordinated display components for effective communication. When threatened by a predator, venomous coral snakes (genus Micrurus) display a vigorous, non-locomotory thrashing behavior that has previously been qualitatively described. Given the high contrast and colorful banding patterns of these snakes, this thrashing display is hypothesized to be a key component of a complex aposematic signal under strong stabilizing selection across species in a mimicry system. By experimentally testing snake response across simulated predator cues, we analyzed variation in the presence and expression of a thrashing display across five species of South American coral snakes. Although the major features of the thrash display were conserved across species, we found that predator cue type, snake body size, and species identity predict significant inter- and intraspecific variation in the propensity to perform a display, the duration of thrashing, and the curvature of snake bodies. We also found an interaction between curve magnitude and body location that clearly shows which parts of the display vary most across individuals and species. Our results suggest that contrary to the assumption that all Micrurus species and individuals perform the same display, a high degree of variation exists despite presumably strong selection to conserve a common signal. This quantitative behavioral characterization presents a new framework for analyzing the non-locomotory motions displayed by snakes in a broader ecological context, especially for signaling systems with complex interaction across multiple modalities.

Un análisis cuantitativo de las serpientes coral (Genero: Micrurus) revela una variación inesperada de los comportamientos anti-depredadores estereotipados dentro de un sistema de mímicoLas señales de advertencia en organismos con defensas químicas son componentes críticos de las interacciones depredador-presa, que a menudo requieren múltiples componentes de visualización coordinados para una comunicación efectiva. Cuando son amenazadas por un depredador, las serpientes de coral venenosas (género Micrurus) muestran un comportamiento vigoroso de coletazos, no locomotor, que solo se ha descrito cualitativamente. Dado el alto contraste y los patrones de bandas coloridas de estas serpientes, se supone que este comportamiento de coletazos es un componente clave de una señal aposemática compleja bajo una fuerte selección estabilizadora entre especies en un sistema de mímica. Al probar experimentalmente la respuesta de las serpientes a través de señales simuladas de depredadores, analizamos la variación en la presencia y la expresión de coletazos en cinco especies de serpientes de coral de América del Sur. Aunque las principales características de la muestra se conservaron en todas las especies, encontramos que el tipo de señal de depredación, el tamaño del cuerpo de la serpiente y la especie en si predicen una variación significativa inter e intraespecífica en la probabilidad a realizar la conducta, la duración del coletazo y la curvatura del cuerpo de las serpientes. También encontramos una interacción entre la magnitud de la curva y la ubicación del cuerpo que muestra claramente qué partes del cuerpo varían más entre individuos y especies. Nuestros resultados sugieren que, contrariamente a la suposición de que todas las especies e individuos realizan el mismo comportamiento, persiste un alto grado de variación en el comportamiento de coletazos exhibido por las serpientes de coral Micrurus a pesar de una selección presumiblemente fuerte para converger en una señal común. Esta caracterización cuantitativa del comportamiento presenta un nuevo marco para analizar los movimientos no locomotores mostrados por las serpientes en un contexto ecológico más amplio, especialmente para los sistemas de señalización con interacción compleja a través de múltiples modalidades. Translated to Spanish by YE Jimenez (yordano_jimenez@brown.edu).