Different factors limit early- and late-season windows of opportunity for monarch development.

Seasonal windows of opportunity are intervals within a year that provide improved prospects for growth, survival, or reproduction. However, few studies have sufficient temporal resolution to examine how multiple factors combine to constrain the seasonal timing and extent of developmental opportunities. Here, we document seasonal changes in milkweed (Asclepias fascicularis)-monarch (Danaus plexippus) interactions with high resolution throughout the last three breeding seasons prior to a precipitous single-year decline in the western monarch population. Our results show early- and late-season windows of opportunity for monarch recruitment that were constrained by different combinations of factors. Early-season windows of opportunity were characterized by high egg densities and low survival on a select subset of host plants, consistent with the hypothesis that early-spring migrant female monarchs select earlier-emerging plants to balance a seasonal trade-off between increasing host plant quantity and decreasing host plant quality. Late-season windows of opportunity were coincident with the initiation of host plant senescence, and caterpillar success was negatively correlated with heatwave exposure, consistent with the hypothesis that late-season windows were constrained by plant defense traits and thermal stress. Throughout this study, climatic and microclimatic variations played a foundational role in the timing and success of monarch developmental windows by affecting bottom-up, top-down, and abiotic limitations. More exposed microclimates were associated with higher developmental success during cooler conditions, and more shaded microclimates were associated with higher developmental success during warmer conditions, suggesting that habitat heterogeneity could buffer the effects of climatic variation. Together, these findings show an important dimension of seasonal change in milkweed-monarch interactions and illustrate how different biotic and abiotic factors can limit the developmental success of monarchs across the breeding season. These results also suggest the potential for seasonal sequences of favorable or unfavorable conditions across the breeding range to strongly affect monarch population dynamics.

System-Wide Improvement for Transitions After Ileostomy Surgery: Can Intensive Monitoring of Protocol Compliance Decrease Readmissions? A Randomized Trial.

BACKGROUND: Hospital readmission is common after ileostomy formation and frequently associated with dehydration. OBJECTIVE: This study was conducted to evaluate a previously published intervention to prevent dehydration and readmission. DESIGN: This is a randomized controlled trial. SETTING: This study was conducted in 3 hospitals within a single health care system. PATIENTS: Patients undergoing elective or nonelective ileostomy as part of their operative procedure were selected. INTERVENTION: Surgeons, advanced practice providers, inpatient and outpatient nurses, and wound ostomy continence nurses participated in a robust ileostomy education and monitoring program (Education Program for Prevention of Ileostomy Complications) based on the published intervention. After informed consent, patients were randomly assigned to a postoperative compliance surveillance and prompting strategy that was directed toward the care team, versus usual care. OUTCOME MEASURES: Unplanned hospital readmission within 30 days of discharge, readmission for dehydration, acute renal failure, estimated direct costs, and patient satisfaction were the primary outcomes measured. RESULTS: One hundred patients with an ileostomy were randomly assigned. The most common indications were rectal cancer (n = 26) and ulcerative colitis (n = 21), and 12 were emergency procedures. Although intervention patients had better postdischarge phone follow-up (90% vs 72%; p = 0.025) and were more likely to receive outpatient intravenous fluids (25% vs 6%; p = 0.008), they had similar overall hospital readmissions (20.4% vs 19.6%; p = 1.0), readmissions for dehydration (8.2% vs 5.9%; p = 0.71), and acute renal failure events (10.2% vs 3.9%; p = 0.26). Multivariable analysis found that weekend discharges to home were significantly associated with readmission (OR, 4.5 (95% CI, 1.2-16.9); p = 0.03). Direct costs and patient satisfaction were similar. LIMITATIONS: This study was limited by the heterogeneous patient population and by the potential effect of the intervention on providers taking care of patients randomly assigned to usual care. CONCLUSIONS: A surveillance strategy to ensure compliance with an ileostomy education program tracked patients more closely and was cost neutral, but did not result in decreased hospital readmissions compared with usual care. See Video Abstract at http://links.lww.com/DCR/A812.

Nodular Lymphocyte Predominant Hodgkin Lymphoma of the Ileum.

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is a rare lymphoma derived from germinal center B lymphocytes that typically presents with localized lymph node involvement and can mimic a variety of both reactive and other neoplastic conditions. Extranodal involvement is uncommon in NLPHL and typically occurs in the context of previously documented or synchronous nodal disease. Involvement of the gastrointestinal tract is exceedingly rare. Here, we present the first case to our knowledge of NLPHL involving the ileum that was discovered incidentally on routine screening colonoscopy in an asymptomatic patient. An awareness of the spectrum of clinical presentations, careful morphologic evaluation, and a comprehensive panel of immunohistochemical stains are essential for correct diagnosis of NLPHL presenting in unusual anatomic sites.

Serine proteases mediate inflammatory pain in acute pancreatitis.

Acute pancreatitis is a life-threatening inflammatory disease characterized by abdominal pain of unknown etiology. Trypsin, a key mediator of pancreatitis, causes inflammation and pain by activating protease-activated receptor 2 (PAR(2)), but the isoforms of trypsin that cause pancreatitis and pancreatic pain are unknown. We hypothesized that human trypsin IV and rat P23, which activate PAR(2) and are resistant to pancreatic trypsin inhibitors, contribute to pancreatic inflammation and pain. Injections of a subinflammatory dose of exogenous trypsin increased c-Fos immunoreactivity, indicative of spinal nociceptive activation, but did not cause inflammation, as assessed by measuring serum amylase and myeloperoxidase activity and by histology. The same dose of trypsin IV and P23 increased some inflammatory end points and caused a more robust effect on nociception, which was blocked by melagatran, a trypsin inhibitor that also inhibits polypeptide-resistant trypsin isoforms. To determine the contribution of endogenous activation of trypsin and its minor isoforms, recombinant enterokinase (ENK), which activates trypsins in the duodenum, was administered into the pancreas. Intraductal ENK caused nociception and inflammation that were diminished by polypeptide inhibitors, including soybean trypsin inhibitor and a specific trypsin inhibitor (type I-P), and by melagatran. Finally, the secretagogue cerulein induced pancreatic nociceptive activation and nocifensive behavior that were reversed by melagatran. Thus trypsin and its minor isoforms mediate pancreatic pain and inflammation. In particular, the inhibitor-resistant isoforms trypsin IV and P23 may be important in mediating prolonged pancreatic inflammatory pain in pancreatitis. Our results suggest that inhibitors of these isoforms could be novel therapies for pancreatitis pain.

Factors that increase risk of colon polyps.

Adenomatous polyps are common and factors that increase risk include race, gender, smoking, and obesity. This author summarizes the evidence supporting increased risk with these factors and describes how epidemiological data may be used to tailor screening programs.

Trends in laparoscopic splenectomy for massive splenomegaly.

HYPOTHESIS: During the past 10 years, expertise with minimally invasive techniques has grown, leading to an increase in successful laparoscopic splenectomy (LS) even in the setting of massive and supramassive spleens. DESIGN: Retrospective series of patients who underwent splenectomy from November 1, 1995, to August 31, 2005. SETTING: Academic tertiary care center. PATIENTS: Adult patients who underwent elective splenectomy as their primary procedure (n = 111). MAIN OUTCOME MEASURES: Demographics, spleen size and weight, conversion from LS to open splenectomy, postoperative length of stay, and perioperative complications and mortality. Massive splenomegaly was defined as the spleen having a craniocaudal length greater than 17 cm or weight more than 600 g, and supramassive splenomegaly was defined as the spleen having a craniocaudal length greater than 22 cm or weight more than 1600 g. RESULTS: Eighty-five (77%) of the 111 patients underwent LS. Of these 85 patients, 25 (29%) had massive or supramassive spleens. These accounted for 40% of LSs performed in 2004 and 50% in 2005. Despite this increase in giant spleens, the conversion rate for massive or supramassive spleens has declined from 33% prior to 1999 to 0% in 2004 and 2005. Since January 2004 at our institution, all of the massive or supramassive spleens have been removed with a laparoscopic approach. Patients with massive or supramassive spleens who underwent LS had no reoperations for bleeding or deaths and had a significantly shorter postoperative length of stay (mean postoperative length of stay, 3.8 days for patients who underwent LS vs 9.0 days for patients who underwent open splenectomy; P<.001). CONCLUSIONS: Despite conflicting reports regarding the safety of LS for massive splenomegaly, our data indicate that with increasing institutional experience, the laparoscopic approach is safe, shortens the length of stay, and improves mortality.

Transient receptor potential vanilloid 1, calcitonin gene-related peptide, and substance P mediate nociception in acute pancreatitis.

The mechanism of pancreatitis-induced pain is unknown. In other tissues, inflammation activates transient receptor potential vanilloid 1 (TRPV1) on sensory nerves to liberate CGRP and substance P (SP) in peripheral tissues and the dorsal horn to cause neurogenic inflammation and pain, respectively. We evaluated the contribution of TRPV1, CGRP, and SP to pancreatic pain in rats. TRPV1, CGRP, and SP were coexpressed in nerve fibers of the pancreas. Injection of the TRPV1 agonist capsaicin into the pancreatic duct induced endocytosis of the neurokinin 1 receptor in spinal neurons in the dorsal horn (T10), indicative of SP release upon stimulation of pancreatic sensory nerves. Induction of necrotizing pancreatitis by treatment with L-arginine caused a 12-fold increase in the number of spinal neurons expressing the proto-oncogene c-fos in laminae I and II of L1, suggesting activation of nociceptive pathways. L-arginine also caused a threefold increase in spontaneous abdominal contractions detected by electromyography, suggestive of referred pain. Systemic administration of the TRPV1 antagonist capsazepine inhibited c-fos expression by 2.5-fold and abdominal contractions by 4-fold. Intrathecal, but not systemic, administration of antagonists of CGRP (CGRP(8-37)) and SP (SR140333) receptors attenuated c-fos expression in spinal neurons by twofold. Thus necrotizing pancreatitis activates TRPV1 on pancreatic sensory nerves to release SP and CGRP in the dorsal horn, resulting in nociception. Antagonism of TRPV1, SP, and CGRP receptors may suppress pancreatitis pain.