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Introduction: Previous reviews have examined female residents' experiences while ante- and postpartum. However, to our knowledge, no review exists that synthesizes medical students' perception of family planning during surgical residencies. We wanted to synthesize current literature on the perceptions of family planning of medical students interested in surgical fields and current medical school policies or resources related to family planning., Methods: A scoping review was performed of databases including MEDLINE (OVID), Scopus, and PubMed in April and September of 2023. Studies were excluded if they were conducted outside the US, occurred before 2003, were opinions, reviews, or editorials, included only non-surgical specialties, focused on only attending years or training years after medical school, and only mentioned "work/life balance" or "lifestyle.", Results: 2295 studies were identified, and a final 19 studies were included. Four major themes were identified among the studies, including family planning as a barrier to a career in surgery, fertility, onsite childcare, and parental leave. Most studies examined general barriers medical students perceive about surgery and included at least one survey question related to family planning. Only two studies focused solely on medical students' knowledge of oocyte preservation, one on on-site childcare at medical schools and one on parental leave during medical school., Conclusion: There is a lack of research examining medical students' knowledge of family planning during a surgical residency and current childbearing policies and resources offered during residency., (Published by Elsevier Inc.)

Background: The threshold at which active surveillance can be considered is variable, with some algorithms proposing nonoperative treatment for differentiated thyroid carcinomas ≤2 cm and lobectomy alone for lesions 2.1-4 cm. To inform both decision for and extent of initial surgery, we aim to evaluate whether molecular results can complement tumor size to identify differentiated thyroid carcinomas associated with disease recurrence., Methods: Patients from 2007-2013 and 2017-2021 who had initial thyroidectomy (differentiated thyroid carcinoma size 1-4 cm, clinical N0M0) were included. When available, molecular testing results were categorized into 3 previously described molecular risk groups (low, intermediate, and high). Primary outcome was structural recurrence., Results: Recurrence was diagnosed in 3.8% of 1,739 patients with differentiated thyroid carcinomas. Preoperative variables including size (1-2 cm vs 2.1-4 cm, P = .43), age >55 years (P = .92), and male sex (P = .31) were not associated with recurrence. Molecular testing results were available for 1,020, and after excluding molecular risk group high-risk differentiated thyroid carcinoma, structural recurrences were associated with molecular risk group intermediate risk (7.2% vs molecular risk group low, 0.7%, P < .001), and most likely in differentiated thyroid carcinoma, which were both 2.1-4 cm and molecular risk group intermediate risk (11.3% vs size 1-2 cm 5.8%, P = .04)., Conclusion: Overall, structural recurrences for differentiated thyroid carcinomas ≤4 cm were low (<5%) and molecuar testing was the only preoperative variable associated with recurrence. However, when molecular risk group intermediate risk was present, larger tumor size (2.1-4 cm) had a 2-fold greater risk of recurrence compared with tumors 1-2 cm, and size may still be helpful to guide management. When considering de-escalated treatment for the proposed guidelines with a cutoff of 2 cm, initial decision-making may be further optimized with identification of preoperative molecular risk groups., Competing Interests: Conflict of Interest/Disclosure Yuri E. Nikiforov and Marina N. Nikiforova own intellectual property for ThyroSeq, receive royalties from the University of Pittsburgh, and are also consultants for Sonic Healthcare USA. The remaining authors have no conflicts of interest or disclosures., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: To determine whether the timing of parathyroid surgery impacts the risk of renal stone retreatment and cardiovascular interventions., Summary Background Data: Long-term, untreated primary hyperparathyroidism is associated with significant morbidity including nephrolithiasis and cardiovascular disease., Methods: We conducted a Population-based Cohort study of New York and California state-wide data from 2000-2020. Adult patients who underwent renal stone treatment and subsequently diagnosed with primary hyperparathyroidism (pHPT) and underwent parathyroidectomy (PTX) were included. Patients were excluded if PTX was prior to index stone procedure, they underwent second stone treatment within 6 months, with stage V CKD, with secondary or tertiary hyperparathyroidism, with prior kidney transplant or hemodialysis, or with prior cancer diagnosis. Rate of renal stone retreatment and cardiovascular interventions after PTX in pHPT patients with nephrolithiasis who underwent parathyroid surgery at ≤ 2 years and >2 years after index stone procedure was measured., Results: We identified 2,093 patients who underwent first-time stone treatment and subsequent PTX. The median time to PTX was 560 days (IQR 187-1477) and follow-up was 7.4 years (IQR 4.5-13.1). Delaying PTX for more than 2 years increased the risk of renal stone retreatment by 59% (HR 1.59; P<0.001), increased the risk of experiencing coronary disease or associated interventions by 118% (HR=2.18; P=0.01), and increased the risk of experiencing an overall cardiovascular event by 52% (HR 1.52; P<0.01)., Conclusions and Relevance: In symptomatic pHPT, delaying PTX significantly increases the risk of requiring future stone retreatment and cardiac/vascular surgical interventions. This highlights the importance of early surgical referral and multidisciplinary approaches to optimize outcomes and resource utilization in pHPT., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Renal hyperparathyroidism due to end-stage kidney disease is associated with considerable morbidity, and when refractory is treated with parathyroidectomy. Recurrent renal hyperparathyroidism is a major surgical complication, yet initial target parathyroid remnant size and outcomes, including rates of recurrence are not well elucidated., Methods: This is a single-institution retrospective cohort study of patients who underwent initial subtotal parathyroidectomy for renal hyperparathyroidism on dialysis, from 1990-2022. The subtotal parathyroidectomy was defined as resection of 3 parathyroid glands ± partial resection of the fourth gland leaving a remnant of ∼75-100 mg, and postresection intraoperative parathyroid hormone goal was 150-250 pg/mL. Clinical data were examined for outcomes., Results: Among 204 patients who met inclusion criteria, 139 (68%) had follow-up data; 58% (80/139) were women and median age was 45 years. Surgical complications included 2 hematomas (1.4%), 1 recurrent laryngeal nerve injury (<1%), and no patient required readmission for intravenous calcium. Using a target remnant size of 75-100 mg, recurrent renal hyperparathyroidism was uncommon (14/139, 10%) and arose at a median interval of 58.6 months (range, 8-180). In cases of recurrence, the postresection intraoperative parathyroid hormone level was less likely to drop <250 pg/mL (40%, 4/10 vs nonrecurrence 65%, 80/123; P = .11) with a slightly lower median decrease (70% vs 81% in nonrecurrence, P = .8); however, neither were significant. Recurrence did not occur in the 19 patients who later received kidney transplantation (P = .2)., Conclusion: In subtotal parathyroidectomy for renal hyperparathyroidism, use of a target 75-100 mg remnant size results in low complication rates. Durable cure appears to be more likely with renal transplantation., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Indeterminate thyroid cytopathology diagnoses represent differing degrees of risk that are corroborated by follow-up studies. However, traditional cytologic-histologic correlation may overestimate the risk of malignancy (ROM) because only a subset of cases undergo resection. Alternatively, some molecular tests provide probability of malignancy data to calculate the molecular-derived risk of malignancy (MDROM) and the positive call rate (PCR). The authors investigated MDROMs and PCRs of indeterminate diagnoses for individual cytopathologists as quality metrics., Methods: This study was approved by the Department of Pathology Quality Improvement Program. Thyroid cytopathology diagnoses and ThyroSeq v3 results were retrieved for each cytopathologist for a 2-year period with at least 3 years of follow-up for the atypia of undetermined significance (AUS), follicular neoplasia (FN), and follicular neoplasia, oncocytic-type (ONC) cytopathologic diagnoses. MDROMs and PCRs were compared with reference ROMs and cytologic-histologic correlation outcomes., Results: The overall MDROMs (and ranges for cytopathologists) for the AUS, FN, and ONC categories were 13.4% (range, 5.8%-20.8%), 28.1% (range, 22.1%-36.7%), and 27.0% (range, 19.5%-41.5%), respectively, and most individual cytopathologists' MDROMs were within reference ROM ranges. However, PCRs more effectively parsed the differences in cytopathologists' ROM performance. Although the overall PCRs were not significantly different across cytopathologists (p = .06), the AUS PCRs were quite different (p = .002). By cytologic-histologic correlation, six of 55 resected cases (10.9%) were falsely negative, and there were no false-positive cases., Conclusions: MDROMs and PCRs evaluate concordance with reference ROMs and with one another and provide individual feedback, which potentially facilitates quality improvement., (© 2023 American Cancer Society.)

Background: Differences in presenting symptoms of primary hyperparathyroidism and outcomes of parathyroidectomy between sexes have been described, but whether these can be assessed by perioperative use of a validated tool, such as the Pasieka Parathyroidectomy Assessment Score, is unknown., Method: All patients with primary hyperparathyroidism were asked to complete symptom assessment at the preoperative and postoperative visits. The assessment included a query for 13 Pasieka Parathyroidectomy Assessment Score parameters evaluated using a visual analog scale as described by Pasieka (summative score 0-1,300), and general quality of life and wellness. A review of a prospectively maintained database of primary hyperparathyroidism patients (January 2016-December 2019) was performed, and those who had a 6-month cure after initial parathyroidectomy were included., Results: The study cohort was mostly women (77%, 541/701). The median preoperative Pasieka Parathyroidectomy Assessment Score was higher in women (155, 0-1,190) than in men (80.5, 0-855, P < .001), although there were similar rates of asymptomatic primary hyperparathyroidism (Pasieka Parathyroidectomy Assessment Score = 0, 12.5% vs 7%, P = .042). After curative parathyroidectomy, women reported a substantial reduction in symptomatology, with Pasieka Parathyroidectomy Assessment Score declining by 35% at initial postoperative visit (median, 155 vs 100, P < .001), further decreasing to 48% by 6 months (155 vs 80, P < .001). The Pasieka Parathyroidectomy Assessment Score in men did change but to a much smaller degree at both the initial postoperative visit (80.5 vs 70; P = .036) and at 6 months (80.5 vs 57.5; P = .048)., Conclusion: When assessed with the Pasieka Parathyroidectomy Assessment Score, improvement in symptoms was clearly demonstrated for women after curative parathyroidectomy. Whether symptom improvement also occurs in men is less apparent but may be due to disparities in the development and validation of outcomes tools in general., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Normocalcemic hyperparathyroidism can occur, but surgery should not be considered until common etiologies for secondary hyperparathyroidism are comprehensively excluded. Calcium deficiency is an underrecognized cause of normocalcemic parathyroid hormone elevation, and we aim to determine if the implementation of a preoperative calcium challenge can be used to reduce unnecessary parathyroidectomy., Methods: Consecutive patients referred for parathyroidectomy (1/21-6/22) with normocalcemia (serum calcium <10 mg/dL) and concurrently elevated parathyroid hormone levels were routinely treated with supplemental calcium and vitamin D3, and follow-up laboratory studies were assessed., Results: A total of 29/314 (9%) patients had normocalcemic parathyroid hormone elevation with mean calcium, parathyroid hormone, and vitamin D 25OH levels of 9.5 ± 0.3 mg/dL, 109.9 ± 34.9 pg/mL, and 42.7 ± 23.8 ng/mL respectively. Confounding factors included estimated glomerular filtration rate <60 in 2, loop diuretic use in 4, and prior gastric bypass or gastric sleeve surgery in 4. Follow-up biochemical evaluation was available in 27 (92%); results were unchanged in 7 patients (26%); normalization of parathyroid hormone levels with persistently normal calcium levels occurred in 15 (55%), thus confirming secondary hyperparathyroidism and hypercalcemia with elevated parathyroid hormone levels (classic primary hyperparathyroidism) was diagnosed in 5 (19%). Parathyroid exploration has been completed for 3 of 5 patients with classic primary hyperparathyroidism to date., Conclusion: A preoperative calcium challenge was prospectively initiated in normocalcemic patients with parathyroid hormone elevation, and there was high compliance (92%). Short-interval calcium supplementation revealed ∼50% to have resolved secondary hyperparathyroidism due to insufficient calcium intake, which avoided unnecessary surgery. In contrast, classic patients were unveiled in 20%, allowing for prompt and correct surgical intervention., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Molecular testing (MT) is emerging as a potential prognostic factor that can be available before treatment of differentiated thyroid carcinoma begins. Among patients eligible for either lobectomy or total thyroidectomy as their initial therapy, our study aims were to assess (1) if conventionally available preoperative factors are associated with incomplete response to initial therapy, and (2) if MT results can be a surrogate for the ATA Risk Stratification System (RSS) to estimate risk of recurrence. Methods: The data of consecutive thyroid cancer patients without preoperative lateral neck disease or distant metastasis who underwent index thyroidectomy between November 1, 2017 and October 31, 2021 were reviewed. Logistic regression models including preoperative variables such as MT and/or the postoperatively available RSS were constructed to predict disease recurrence, either structural or biochemical. Model discrimination using the c-statistic and goodness-of-fit test were compared. Results: Among 945 patients studied, 50 (5.2%) recurred with 18-month median follow-up. Recurrences were detected in 17 (2.9%), 20 (6.7%), and 13 (22.8%) patients with RSS-low, -intermediate, and -high cancers, respectively ( p  < 0.001). In multivariable analysis, only tumor size was associated with recurrence (odds ratio [OR] 1.3, 95% confidence interval [CI] 1.1-1.5). In a different model analyzing 440 (46.6%) patients with available MT results, recurrence was associated with both larger tumor size (OR 1.4 [95% CI 1.1-1.8]) and MT results ( p  < 0.001). Including MT improved the c-statistic by 27%, which was statistically no different than the model incorporating only the RSS ( p  = 0.15). Conclusions: Disease recurrence was observed across all ATA RSS categories in short-term follow-up, and tumor size was the only conventional preoperative factor associated with recurrence. When MT results were incorporated, they not only improved predictive ability beyond tumor size alone, but also yielded similar ability as the gold standard ATA RSS. Thus, MT results might aid the development of novel preoperative risk stratification algorithms.

Background: Attempts at preoperative localization of abnormal parathyroid gland(s) in primary hyperparathyroidism (pHPT) can be performed with a variety of modalities. Study utilization is surgeon-specific with highly variable opinions in parathyroid surgery. As more people are diagnosed with pHPT, the complexity of the disease has given rise to variation in management. This heterogeneity raises the question of the true clinical practice of imaging among individual endocrine surgeons., Methods: To better understand the preoperative parathyroid imaging practices of endocrine surgeons, an email-based survey was disseminated to the program directors of 22 American Association of Endocrine Surgeons fellowship programs querying them on their initial diagnostic test of choice for pHPT. Clinical support team members from each respective program were subsequently contacted and answers were compared., Results: Sixty-eight percent (15/22) of clinical team members recommended either an additional (12/15) or different imaging test (3/15) than what was recommended by their institution's endocrine surgeon. The most common initial imaging test that was repeated by both the endocrine surgeon and clinical team member was neck ultrasound; 33% of clinical team members (7/22) responded concordantly to their surgeon with ultrasound as the initial recommendation., Discussion: Significant variability exists in the preoperative approach to patients with hyperparathyroidism. Here, we demonstrate that inconsistency in preoperative imaging recommendations even extends to within an individual surgeon's practice based on the impact of the clinical support team, highlighting the role for improved clinical protocols within an institution's clinical team.

Background: Normocalcemic primary hyperparathyroidism (PHPT) has been shown to benefit from parathyroidectomy. PHPT may be localized preoperatively with various imaging modalities, but the utility of preoperative imaging in normocalcemic PHPT compared to hypercalcemic PHPT is not well defined., Methods: Retrospective review was performed on all PHPT patients who underwent parathyroidectomy from 2001 to 2019. Patients were stratified into normocalcemic and hypercalcemic groups. Patient and outcomes data were analyzed., Results: All 2218 patients in this database were included. 433 patients had normocalcemic PHPT (19.5%) and 1785 had hypercalcemic PHPT (80.5%). Among normocalcemic patients, equivalent cure rates were seen between patients with preoperative imaging versus those without (100% vs 99%). No differences in postoperative complications were demonstrated except for a slightly increase in transient hypocalcemia in patients without imaging., Conclusions: Normocalcemic PHPT patients had equivalent cure and similar complication rates with or without preoperative imaging compared to hypercalcemic patients. Routine localization studies in normocalcemic PHPT may be safely omitted in favor of exploration with intraoperative adjuncts by experienced surgeons., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: The decision to pursue lobectomy versus total thyroidectomy is highly individualized. The rate of thyroid hormone replacement therapy after lobectomy varies considerably (15%-48%) and studies are limited by short-term follow-up. We sought to assess long-term thyroid hormone replacement therapy-requirement for lobectomy., Methods: Patients undergoing lobectomy from January 2005 to July 2010 at an academic institution were reviewed. Demographic, laboratory, pathology, and thyroid hormone replacement therapy use were compared., Results: In total, 235 patients were included. The rate of thyroid hormone replacement therapy after lobectomy was 46.8% (110/235). The majority were female (84.7%), with a mean age of 52 ± 1 years, 97% with benign pathology, and the median duration of follow-up was 7.2 years. Among the 110 thyroid hormone replacement therapy, the mean postoperative thyroid stimulating hormone level 9.08 ± 0.96m IU/L and the time to thyroid hormone replacement therapy-initiation was 621 days; 24% started therapy ≥2 years after surgery. There was no difference in age, sex, or malignancy. Hashimoto thyroiditis was diagnosed in 21.8% patients who underwent thyroid hormone replacement therapy versus 8.0% of those without thyroid hormone replacement therapy (odds ratio 3.2; 95% confidence interval, 1.43-6.79; P < .001). On multivariate analysis, only Hashimoto thyroiditis was independently associated with thyroid hormone replacement therapy use (odds ratio 2.88; 95% confidence interval, 1.3-6.6; P = .012)., Conclusion: With long-term follow-up, nearly 50% of patients who underwent lobectomy for benign disease required thyroid hormone replacement therapy and nearly one-quarter of these patients not starting until ≥2 years after surgery. Therefore, patients who undergo thyroid lobectomy should be counseled appropriately and thyroid function followed for a minimum of 2 years., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: The American College of Radiology Thyroid Imaging Reporting and Data System for ultrasound classification of malignancy risk was developed to better triage thyroid nodules for fine-needle aspiration biopsy. To examine further, we compared thyroid cytologic classification rates in nodules before and after institutional Thyroid Imaging Reporting and Data System implementation., Methods: Cytology diagnoses by Bethesda criteria (categories I-VI) from January 2014 to October 2021 were retrieved; observed changes in yearly category frequency were analyzed by linear regression; and pooled cohorts of pre- (2014-2018) and post-Thyroid Imaging Reporting and Data System (2019-2021) cytology call rates were compared., Results: Overall, 7,413 cytologic specimens were included (range/year 715-1,444). From 2014 to 2021, the proportion of benign (Bethesda category II) diagnosis per year declined stepwise from 49.7% to 19.4%, and atypia of undetermined significance/follicular lesion of undetermined significance (Bethesda category III) increased sequentially from 21.3% to 51.5%. Between 2014 and 2021, Bethesda category III diagnosis increased on average by 4.8% per year (95% confidence internal, 3.29-5.54; P < .001) and Bethesda category II results decreased on average by 4.4% per year (95% confidence interval, 6.29-3.42; P < .001). When comparing pre- and post-Thyroid Imaging Reporting and Data System, the proportion of Bethesda category II cytology results decreased (43.1% vs 21%; P = .001) while Bethesda category III (28.3% vs 47.7%; P = .002) and Bethesda category V (1.1% vs 1.7%; P = .015) results increased., Conclusion: After implementation of American College of Radiology Thyroid Imaging Reporting and Data System ultrasound criteria, we observed a 2.5-fold decline in the rate of benign cytology and an increase in the proportion of atypia of undetermined significance/follicular lesion of undetermined significance results., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Molecular testing improves the diagnostic accuracy of thyroid cancer. Whether specific molecular testing results are associated with tumor phenotype or provide prognostic information needs further delineation., Methods: Consecutive thyroid cancer patients after index thyroidectomy with ThyroSeq version 3 (Rye Brook, NY) molecular testing obtained on preoperative fine-needle aspiration or thyroidectomy specimens from patients with thyroid cancer were categorized into 3 molecular risk groups based on detected mutations, fusions, copy number alterations, and/or gene expression alterations and correlated with histopathology and recurrence, defined as biochemical or structural., Results: Of 578 patients, 49.9%, 37.5%, and 12.6% had molecular risk group-low, molecular risk group-intermediate, and molecular risk group-high cancers, respectively. With a median 19-month follow-up, 9.1% patients recurred. Compared with molecular risk group-low, molecular risk group-intermediate cancers were diagnosed in younger patients and more often had microscopic extrathyroidal extension, involved margins, and nodal disease. Compared with molecular risk group-intermediate, molecular risk group-high cancers were diagnosed in older patients and more often had gross extrathyroidal extension and vascular invasion. In multivariable analysis, recurrence was more likely in molecular risk group-high cancers than in molecular risk group-intermediate (hazard ratio = 4.0; 95% confidence interval, 1.9-8.6; P < .001) and more likely in molecular risk group-intermediate than in molecular risk group-low (hazard ratio = 5.0; 95% confidence interval, 2.0-12.5; P < .001)., Conclusion: Using modern comprehensive genotyping, the genetic profile of thyroid cancers can be categorized into 3 novel molecular risk groups that were associated with histopathologic phenotype and recurrence in short-term follow-up., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Liver metastasis from duodenopancreatic neuroendocrine neoplasms (DP-NENs) is a major cause of mortality in multiple endocrine neoplasia type 1 (MEN1) patients, yet much of their natural history is unknown., Methods: This longitudinal, retrospective cohort study analyzed all MEN1 patients with imageable functional (F) and nonfunctional (NF) DP-NENs (1990-2021) for liver metastasis-free survival (LMFS) and overall survival (OS)., Results: Of 138 patients, 85 (61.6%) had imageable DP-NENs (28 F, 57 NF), and the mean largest tumor size was 1.8 ± 1.4 cm. Multifocality was present in 32 patients (37.7%). Surgery was performed for 49 patients (57.7%). During an 11-year median follow-up period (IQR, 6-17 years), 23 (27.1%) of the patients had liver metastasis, and 19 (22.4%) patients died. Death was attributed to liver metastasis in 60% of cases. The patients with F-DP-NENs versus NF-DP-NENs more often had liver metastasis (46.4% vs. 15.8%; p = 0.002) but had similar 10-year LMFS (80.9 vs. 87.0%; p = 0.44) and OS (82.7 vs. 94.3%; p = 0.69). The patients with NF-DP-NENs had surgery when their tumors were larger (p < 0.001). Tumor size was not associated with liver metastasis (p = 0.89). The average growth rate was 0.04 cm/year (SE, 0.02 cm/year; p = 0.01) during active surveillance for NF-DP-NENs (n = 38). Liver metastasis developed in four patients with tumors smaller than 2 cm. The risk of liver metastasis was independent of surgery (hazard ratio [HR], 0.78; 95% confidence interval [CI], 0.21-2.93; p = 0.72) and death (HR, 0.51; 95% CI, 0.08-3.06; p = 0.46)., Conclusions: Although the observed outcomes in this study were better than historical data, small NF-DP-NENs still developed liver metastasis and liver metastasis remains a major cause of death. These results suggest that size as a sole criterion for surgery may be insufficient to predict tumor behavior., (© 2022. Society of Surgical Oncology.)

Expression of the tight junction-associated protein junctional adhesion molecule-A (JAM-A) is increased in sepsis, although the significance of this is unknown. Here, we show that septic JAM-A -/- mice have increased gut permeability, yet paradoxically have decreased bacteremia and systemic TNF and IL-1β expression. Survival is improved in JAM-A-/- mice. However, intestine-specific JAM-A-/- deletion does not alter mortality, suggesting that the mortality benefit conferred in mice lacking JAM-A is independent of the intestine. Septic JAM-A-/- mice have increased numbers of splenic CD44hiCD4+ T cells, decreased frequency of TNF+CD4+ cells, and elevated frequency of IL-2+CD4+ cells. Septic JAM-A-/- mice have increased numbers of B cells in mesenteric lymph nodes with elevated serum IgA and intraepithelial lymphocyte IgA production. JAM-A-/- × RAG-/- mice have improved survival compared with RAG-/- mice and identical mortality as WT mice. Gut neutrophil infiltration and neutrophil phagocytosis are increased in JAM-A-/- mice, while septic JAM-A-/- mice depleted of neutrophils lose their survival advantage. Therefore, increased bacterial clearance via neutrophils and an altered systemic inflammatory response with increased opsonizing IgA produced through the adaptive immune system results in improved survival in septic JAM-A-/- mice. JAM-A may be a therapeutic target in sepsis via immune mechanisms not related to its role in permeability.

Introduction: Parathyroidectomy is the standard management for patients with tertiary hyperparathyroidism (THPT) and hypercalcemia. However, a subset of patients with THPT have normal or mildly-elevated serum calcium levels in the setting of significantly elevated parathyroid hormone (PTH). The purpose of this study is to determine the effectiveness and safety of parathyroidectomy in normocalcemic THPT., Materials and Methods: Retrospective review of 212 consecutive patients with THPT who subsequently underwent parathyroidectomy between 2001 and 2020 was performed. Patients were categorized as normocalcemic, "mild" (Ca ≤ 10.4 mg/dL) or hypercalcemic, "classic" THPT (Ca ≥ 10.5 mg/dL) and clinical data are compared., Results: 71 of 212 (34%) were normocalcemic with median pre-operative Ca and PTH levels of 9.7 mg/dL and 225pg/mL, respectively and 141 of 212 (67%) were hypercalcemic with median preoperative Ca and PTH levels of 11 mg/dL and 211pg/mL, respectively. The mean length of stay was shorter in normocalcemic patients (0.33 versus 0.50 d; P = 0.03). 10 of 71 (14%) normocalcemic patients underwent reoperative parathyroidectomy, more than double that of hypercalcemic patients (5.6%; P = 0.06). Concomitant thymectomy was performed in 28.1% and 22.1% of normocalcemia and hypercalcemic patients, respectively (P = 0.44). No patient in either group required intravenous calcium or had undetectable PTH levels, but permanent hypocalcemia was more frequent in normocalcemic compared to hypercalcemic patients (11.2% versus 1.4%; P = 0.03)., Conclusions: Parathyroidectomy for normocalcemic tertiary hyperthyroidism (HPT) can be performed safely. These data can help guide multidisciplinary discussions for earlier surgical referral and intervention. Future investigations are needed to evaluate the impact of parathyroidectomy on the renal allograft, bone health, and cardiovascular disease., (Copyright © 2022. Published by Elsevier Inc.)

Salt is one of the most common abiotic stresses, causing ionic and osmotic pressure changes that affect plant growth and development. In this work, we present molecular and genetic evidence that Arabidopsis Toxicos en Levadura 12 (ATL12) is involved in both salt stress and in the abscisic acid response to this stress. We demonstrate that ATL12 is highly induced in response to salt stress and that atl12 mutants have a lower germination rate, decreased root length, and lower survival rate compared to the Col-0 wild-type in response to salt stress. Overexpression of ATL12 increases expression of the salt stress-associated genes SOS1/2 , and ABA-responsive gene RD29B . Additionally, higher levels of reactive oxygen species are detected when ATL12 is overexpressed, and qRT-PCR showed that ATL12 is involved in the AtRBOHD/F -mediated signaling. ATL12 expression is also highly induced by ABA treatment. Mutants of atl12 are hypersensitive to ABA and have a shorter root length. A decrease in water loss and reduced stomatal aperture were also observed in atl12 mutants in response to ABA. ABA-responsive genes RD29B and RAB18 were downregulated in atl12 mutants but were upregulated in the overexpression line of ATL12 in response to ABA. Taken together our results suggest that ATL12 modulates the response to salt stress and is involved in the ABA signaling pathway in Arabidopsis thaliana .

Background: Hypoparathyroidism is the most common complication of bilateral operations in the central neck. No formal guidelines exist for the management of permanent hypoparathyroidism. Current treatment involving medical supplementation increases resource utilization and patient morbidity while decreasing quality of life. Parathyroid allotransplant (PA) offers a promising therapy; however, the optimal technique and role of immunosuppression (IS) in PA remain unclear., Methods: We performed a systematic search of the Embase, MEDLINE, and Cochrane Library databases to identify studies investigating PA for treatment of hypoparathyroidism., Results: A total of 24 studies including 186 individual allograft transplants in 146 patients were identified. Pooled graft survival for allotransplants in transplant-naïve vs prior transplant recipients was 29.9% and 80%, respectively., Conclusions: PA using normocellular, fresh parathyroid donor tissue that is ABO-compatible, with induction and, at minimum, short-term maintenance IS presents a potentially safe and effective therapeutic option for permanent hypoparathyroidism in patients tolerating IS., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: The majority of ectopic mediastinal parathyroid adenomas are accessible transcervically and those not amenable to this approach pose a significant clinical and technical challenge., Methods: Retrospective review of transthoracic robot-assisted mediastinal parathyroidectomy (TTRMP) for primary hyperparathyroidism between 2012 and 2019 at a single institution., Results: 16 patients underwent TTRMP, 63% were female with a mean age of 64 ± 2.0 years. Nine of 16 had prior parathyroidectomy; 80% had persistent disease and a mean 2.8-year delay from index operation until TTRMP. Locations included: intrathymic (8), AP window (4), carina (3), and retroesophageal (1). Two patients underwent parathyroid reimplantation. Mean post-operative calcium and PTH were 9.2 ± 0.2 mg/dL and 20.2 ± 5.6 pg/mL, respectively. Complications included: temporary hypocalcemia (4), permanent hypocalcemia (1), DVT (1), hoarseness (1), and subcostal neuralgia (1)., Conclusion: In experienced hands, TTRMP is a safe and effective approach to mediastinal parathyroids not accessible transcervically. A multidisciplinary approach should be used in reoperative cases., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Parathyroidectomy for primary hyperparathyroidism (pHPT) is safely performed in the outpatient setting in the adult population. However, concern that children and adolescents have higher complication rates and are unable to recognize and communicate symptoms of hypocalcemia has limited same-day discharges in the pediatric population., Methods: Nineteen patients aged 8-18 years (14.1 ± 0.7) underwent outpatient parathyroidectomy for pHPT by a single high-volume endocrine surgeon from 2002-2020. Patient demographics, disease, operations, and complications were reviewed., Results: Sixteen of 19 patients were symptomatic with fatigue (62.5%), joint pain (37.5%) and nephrolithiasis (18.7%) most common. Mean preoperative Ca and PTH were 11.7 ± 0.3 mg/dL and 102.3 ± 11.8pg/mL, respectively. Ten of 19 had a single adenoma and 9 had multigland hyperplasia including one MEN1 and one MEN2A patient. We performed 11 four-gland explorations, 8 unilateral parathyroidectomies; including 9 transcervical thymectomies, 1 total thyroidectomy, and 1 bilateral central neck dissection. Mean 6-month postoperative Ca and PTH levels were 9.5 ± 0.3 mg/dL (range 7.3-10.3) and 29±5.0pg/mL (range 6.3-77), respectively. One patient developed permanent hypoparathyroidism and 1 had temporary hypocalcemia. No temporary or permanent hoarseness, unplanned same-day admission, wound complications, or Emergency Department visits occurred., Conclusion: Outpatient parathyroidectomy can be safely and effectively performed in pediatric patients with primary HPT., Level of Evidence: Treatment Study, Level III., Competing Interests: Declaration of Competing Interest None., (Copyright © 2021. Published by Elsevier Inc.)

Plants use diverse strategies to defend themselves from biotic stresses in nature, which include the activation of defense gene expression and a variety of signal transduction pathways. Previous studies have shown that protein ubiquitination plays a critical role in plant defense responses, however the details of its function remain unclear. Our previous work has shown that increasing expression levels of ATL9 , an E3 ubiquitin ligase in Arabidopsis thaliana, increased resistance to infection by the fungal pathogen, Golovinomyces cichoracearum . In this study, we demonstrate that the defense-related proteins PDF1.2, PCC1 and FBS1 directly interact with ATL9 and are targeted for degradation to the proteasome by ATL9. The expression levels of PDF1.2 , PCC1 and FBS1 are decreased in T-DNA insertional mutants of atl9 and T-DNA insertional mutants of pdf1.2 , pcc1 and fbs1 are more susceptible to fungal infection. In addition, callose is more heavily deposited at infection sites in the mutants of atl9 , fbs1 , pcc1 and pdf1.2 . Overexpression of ATL9 and of mutants in fbs1 , pcc1 and pdf1.2 showed increased levels of cell death during infection. Together these results indicate that ubiquitination, cell death and callose deposition may work together to enhance defense responses to fungal pathogens.

Plants, as sessile organisms, have evolved complex systems to respond to changes in environmental conditions. Chitin is a Pathogen-Associated-Molecular Pattern (PAMP) that exists in the fungal cell walls, and can be recognized by plants and induce plant pattern-triggered immunity (PTI). Our previous studies showed that Arabidopsis Toxicos en Levadura 12 (ATL12) is highly induced in response to fungal infection and chitin treatment. We used the model organism Arabidopsis thaliana to characterize ATL12 and explore its role in fungal defense. Histochemical staining showed that pATL12 -GUS was continually expressed in roots, leaves, stems, and flowers. Subcellular co-localization of the ATL12-GFP fusion protein with the plasma membrane-mcherry marker showed that ATL12 localizes to the plasma membrane. Mutants of atl12 are more susceptible to Golovinomyces &nbsp; cichoracearum infection, while overexpression of ATL12 increased plant resistance to the fungus. ATL12 is highly induced by chitin after two hours of treatment and ATL12 may act downstream of MAPK cascades. Additionally, 3,3'-diaminobenzidine (DAB) staining indicated that atl12 mutants generate less reactive oxygen species compared to wild-type Col-0 plants and RT-PCR indicated that ATL12- regulated ROS production may be linked to the expression of respiratory burst oxidase homolog protein D/F ( AtRBOHD/F ). Furthermore, we present evidence that ATL12 expression is upregulated after treatment with both salicylic acid and jasmonic acid. Taken together, these results suggest a role for ATL12 in crosstalk between hormonal, chitin-induced, and NADPH oxidase-mediated defense responses in Arabidopsis.

Introduction: Papillary thyroid cancer (PTC) is the most common form of thyroid cancer. Although the survival rate is excellent, recurrence is as high as 20%. The mainstay of therapy is thyroidectomy and lymph node dissection based on risk factors. Data from other cancers suggest that surgical outcomes are most optimal at comprehensive cancer centers. We hypothesize that patients with PTC who had their initial operation at a comprehensive cancer center would have a better oncologic outcome., Methods: We utilized an IRB-approved cancer care registry database of patients with thyroid cancer who were seen at our institution between 2000 and 2018. Patient records were updated with cancer-specific outcomes including recurrence and need for re-intervention. Clinical and surgical outcomes were then compared between patients who had their initial operation at a comprehensive cancer center (CCC group, n = 503) versus those who did not (non-CCC group, n = 72)., Results: Mean patient age was 49 ± 16 years and 70% were female. Average tumor size was 1.6 ± 1.6 cm. There was no difference in tumor size, age, gender or race between groups. Pre-operative ultrasound was more frequently performed at the CCC (89%) than at non-CCC's (51%, p < 0.001). CCC patients were more likely to undergo initial total thyroidectomies compared to non-CCC patients (76% vs. 21%, p < 0.001). Positive surgical margins were more frequently found in patients at non-CCC's (19%) than at the CCC (9.7%, p = 0.016). Finally, CCC patients had a significantly lower cancer recurrence rate (5.0% vs. 37.5%, p < 0.001). Therefore, the need for additional cancer operations was much greater in patients who had initial thyroid surgery at non-CCC (31.9% vs. 1.4%, p < 0.001)., Conclusions: Patients with PTC who have their initial thyroidectomy at non-CCC have higher recurrence rates, higher rates of positive tumor margins on pathology, and increased need for additional operations. These data suggest that patients who have their initial procedure at a CCC for PTC have better long-term outcomes., Competing Interests: Declaration of competing interest The authors report no proprietary or commercial interest in any product mentioned or concept discussed in this article., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Central neck dissection (CND) remains a controversial intervention for papillary thyroid carcinoma (PTC) patients with clinically negative nodes (cN0) in the central compartment. Proponents state that CND in cN0 patients prevents locoregional recurrence, while opponents deem that the risks of complications outweigh any potential benefit. Thus, there remains conflicting results amongst studies assessing oncologic and surgical outcomes in cN0 PTC patients who undergo CND. To provide clarity to this controversy, we sought to evaluate the efficacy, safety, and oncologic impact of CND in cN0 PTC patients at our institution., Materials and Methods: Six hundred and ninety-five patients with PTC who underwent thyroidectomy at our institution between 1998 and 2018 were identified using an institutional cancer registry and supplemental electronic medical record queries. Patients were stratified by whether or not they underwent CND; identified as CND(+) or CND(-), respectively. Patients were also stratified by whether or not they received adjuvant radioactive iodine (RAI) therapy. Patient demographics, pathologic results, as well as surgical and oncologic outcomes were reviewed. Standard statistical analyses were performed using ANOVA and/or t-test and chi-squared tests as appropriate., Results: Among the 695 patients with PTC, 492 (70.8%) had clinically and radiographically node negative disease (cN0). The mean age was 50 ± 1 years old and 368 (74.8%) were female. Of those with cN0 PTC, 61 patients (12.4%) underwent CND. CND(+) patients were found to have higher preoperative thyroid stimulating hormone (TSH) values, 2.8 ± 0.8 versus 1.5 ± 0.2 mU/L (P = 0.028) compared to CND(-) patients. CND did not significantly decrease disease recurrence, development of distant metastatic disease (P = 0.105) or persistence of disease (P = 0.069) at time of mean follow-up of 38 ± 3 months compared to CND(-) patients. However, surgical morbidity rates were significantly higher in CND(+) patients; including transient hypocalcemia (36.1% versus 14.4%; P < 0.001), transient recurrent laryngeal nerve (RLN) injury (19.7% vers us 7.0%; P < 0.001), and permanent RLN injury (3.3% versus 0.7%; P < 0.001)., Conclusions: The majority of patients at our institution with cN0 PTC did not undergo CND. This data suggests that CND was not associated with improvements in oncologic outcomes during the short-term follow-up period and led to increased postoperative morbidity. Therefore, we conclude that CND should not be routinely performed for patients with cN0 PTC., (Copyright © 2021. Published by Elsevier Inc.)

TIGIT is a recently identified coinhibitory receptor that is upregulated in the setting of cancer and functionally contributes to the impairment of antitumor immunity. However, its role during sepsis is unknown. Because patients with cancer are 10 times more likely to die of sepsis than previously healthy (PH) patients with sepsis, we interrogated the role of TIGIT during sepsis in the context of preexistent malignancy. PH mice or cancer (CA) mice inoculated with lung carcinoma cells were made septic by cecal ligation and puncture (CLP). We found that sepsis induced TIGIT upregulation predominantly on Tregs and NK cells in both PH and CA mice. Anti-TIGIT Ab improved the 7-d survival of CA septic mice but not PH mice after CLP. Treatment of CA septic animals but not PH septic animals with anti-TIGIT mAb significantly reversed sepsis-induced loss of CD4+ T cells, CD8+ T cells, Foxp3+ Treg, and CD19+ B cells in the spleen, which was the result of decreased caspase-3+ apoptotic cells. In sum, we found that anti-TIGIT Ab reversed sepsis-induced T cell apoptosis in CA septic mice and led to a significant survival benefit, suggesting its use as a potential immunotherapy to improve outcomes in septic patients with cancer.

Background: Re-operative parathyroidectomy in patients with recurrent or persistent hyperparathyroidism can be challenging. We review our experience to determine the optimal number of localization studies prior to re-operation., Methods: From 2001 to 2019, 251 patients underwent re-operative parathyroidectomy. Parathyroidectomies were stratified to 4 groups based upon the number of positive localization studies obtained: A) ZERO, B) 1-positive, C) 2-positive, D) 3-positive., Results: The overall cure rate was 97%, where 201 single gland resections, 23 two-gland resections, 22 subtotal/total, and 5 forearm autograft resections were performed. Thirty-two patients had no positive studies (A), 172 patients had 1-positive (B), 42 patients had 2-positive (C), and 5 patients had 3-positive studies (D). There was no difference in surgical cure rates between groups (p = 0.71). The majority of patients had one or no positive imaging studies yet almost all still achieved cure., Conclusion: Successful re-operative parathyroidectomy can be performed with minimal pre-operative scans in certain clinical contexts., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to disclose., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Patients with cancer are at an increased risk of developing and dying from sepsis. We previously reported that blockade of the chemokine receptor CXCR4 resulted in decreased CD4 + T cell exhaustion and improved survival in a model of polymicrobial sepsis in previously healthy mice. Here, we sought to determine whether CXCR4 blockade could improve mortality and immune dysregulation during sepsis complicated with malignancy. Results in animals inoculated with a lung cancer cell line and subjected to CLP 3 weeks later indicated that CXCR4 was up-regulated on naïve and central memory T cells following sepsis. Of note, and in contrast to results in previously healthy mice, CXCR4 blockade failed to improve survival in cancer septic animals; instead, it actually significantly worsened survival. In the setting of cancer, CXCR4 blockade failed to result in T cell egress from the bone marrow, reverse lymphopenia in the spleen, or reverse T cell exhaustion. Mechanistically, elevated expression of CD69 on naïve T cells in the bone marrow of cancer septic animals was associated with their inability to egress from the bone marrow in the setting of CXCR4 blockade. In conclusion, these results illuminate the differential impact of CXCR4 blockade on sepsis pathophysiology in the setting of cancer and highlight the need for personalized therapy during sepsis., (©2020 Society for Leukocyte Biology.)

Insulinomas are rare endocrine malignancies of the pancreas that require surgical resection but can be difficult to localize preoperatively. We sought to review and improve the accuracy of preoperative localization techniques at our institution. We retrospectively reviewed all insulinomas that underwent resection at our institution between 1998 and 2016. Localization techniques include selective arterial calcium stimulation (CaStim), CT, MRI, angiography, and somatostatin receptor scintigraphy. Thirty-eight patients had pathologically proven insulinomas on surgical resection. Localization accuracies of CaStim, CT, and MRI were 89 per cent (31/35), 67 per cent (22/33), and 46 per cent (11/24), respectively. When compared with CT alone and CaStim alone, the combination of these two modalities resulted in 100 per cent preoperative localization (30/30), whereas the use of CaStim alone resulted in 80 per cent (4/5) localization and the use of CT alone resulted in 66 per cent (2/3) localization. Four of our patients had both negative CT and MRI. Among these patients, CaStim was 100 per cent localizing and the only positive modality for these patients. These data confirm that CaStim is accurate in preoperatively identifying single and multiple insulinomas; and when combined with CT, this accuracy is increased to 100 per cent. Based on these data, we propose that a dual imaging approach is a superior means of preoperative localization.

Sepsis is a dysregulated systemic response to infection involving many inflammatory pathways and the induction of counter-regulatory anti-inflammatory processes that results in a state of immune incompetence and can lead to multi-organ failure. CXCR4 is a chemokine receptor that, following ligation by CXCL12, directs cells to bone marrow niches and also plays an important role in T cell cosignaling and formation of the immunological synapse. Here, we investigated the expression and function of CXCR4 in a murine model of polymicrobial sepsis. Results indicate that CXCR4 is selectively upregulated on naïve CD4+ and CD8+ T cells and CD4+ central memory T cells following the induction of sepsis, and that CXCR4 antagonism resulted in a significant decrease in sepsis-induced mortality. We probed the mechanistic basis for these findings and found that CXCR4 antagonism significantly increased the number of peripheral CD4+ and CD8+ T cells following sepsis. Moreover, mice treated with the CXCR4 antagonist contained fewer PD-1+ LAG-3+ 2B4+ cells, suggesting that blockade of CXCR4 mitigates CD4+ T cell exhaustion during sepsis. Taken together, these results characterize CXCR4 as an important pathway that modulates immune dysfunction and mortality following sepsis, which may hold promise as a target for future therapeutic intervention in septic patients.

Plants are continually exposed to a variety of pathogenic organisms, including bacteria, fungi and viruses. In response to these assaults, plants have developed various defense pathways to protect themselves from pathogen invasion. An understanding of the expression and regulation of genes involved in defense signaling is essential to controlling plant disease. ATL9, an Arabidopsis RING zinc finger protein, is an E3 ubiquitin ligase that is induced by chitin and involved in basal resistance to the biotrophic fungal pathogen, Golovinomyces cichoracearum (G. cichoracearum). To better understand the expression and regulation of ATL9, we studied its expression pattern and the functions of its different protein domains. Using pATL9:GUS transgenic Arabidopsis lines we found that ATL9 is expressed in numerous tissues at various developmental stages and that GUS activity was induced rapidly upon wounding. Using a GFP control protein, we showed that ATL9 is a short-lived protein within plant cells and it is degraded via the ubiquitin-proteasome pathway. ATL9 contains two transmembrane domains (TM), a RING zinc-finger domain, and a PEST domain. Using a series of deletion mutants, we found that the PEST domain and the RING domain have effects on ATL9 degradation. Further infection assays with G. cichoracearum showed that both the RING domain and the TM domains are important for ATL9's resistance phenotype. Interestingly, the PEST domain was also shown to be significant for resistance to fungal pathogens. This study demonstrates that the PEST domain is directly coupled to plant defense regulation and the importance of protein degradation in plant immunity.

Postoperative acute renal failure is a major cause of morbidity and mortality in colon and rectal surgery. Our objective was to identify preoperative risk factors that predispose patients to postoperative renal failure and renal insufficiency, and subsequently develop a risk calculator. Using the National Surgical Quality Improvement Program Participant Use Files database, all patients who underwent colorectal surgery in 2009 were selected (n = 21,720). We identified renal complications during the 30-day period after surgery. Using multivariate logistic regression analysis, a predictive model was developed. The overall incidence of renal complications among colorectal surgery patients was 1.6 per cent. Significant predictors include male gender (adjusted odds ratio [OR]: 1.8), dependent functional status (OR: 1.5), preoperative dyspnea (OR: 1.5), hypertension (OR: 1.6), preoperative acute renal failure (OR: 2.0), American Society of Anesthesiologists class ≥3 (OR: 2.2), preoperative creatinine >1.2 mg/dL (OR: 2.8), albumin <3.5 g/dL (OR: 1.8), and emergency operation (OR: 1.5). This final model has an area under the curve (AUC) of 0.79 and was validated with similar excellent discrimination (area under the curve: 0.76). Using this model, a risk calculator was developed with excellent predictive ability for postoperative renal complications in colorectal patients and can be used to aid clinical decision-making, patient counseling, and further research on measures to improve patient care.

CD8 T cell loss and dysfunction have been implicated in the increased susceptibility to opportunistic infections during the later immunosuppressive phase of sepsis, but CD8 T cell activation and attrition in early sepsis remain incompletely understood. With the use of a CLP model, we assessed CD8 T cell activation at 5 consecutive time points and found that activation after sepsis results in a distinct phenotype (CD69 + CD25 int CD62L HI ) independent of cognate antigen recognition and TCR engagement and likely through bystander-mediated cytokine effects. Additionally, we observed that sepsis concurrently results in the preferential depletion of a subset of memory-phenotype CD8 T cells that remain "unactivated" (i.e., fail to up-regulate activation markers) by apoptosis. Unactivated CD44 HI OT-I cells were spared from sepsis-induced attrition, as were memory-phenotype CD8 T cells of mice treated with anti-LFA-1 mAb, 1 h after CLP. Perhaps most importantly, we demonstrate that attrition of memory phenotype cells may have a pathologic significance, as elevated IL-6 levels were associated with decreased numbers of memory-phenotype CD8 T cells in septic mice, and preservation of this subset after administration of anti-LFA-1 mAb conferred improved survival at 7 d. Taken together, these data identify potentially modifiable responses of memory-phenotype CD8 T cells in early sepsis and may be particularly important in the application of immunomodulatory therapies in sepsis., (© Society for Leukocyte Biology.)

Increasing use of iron oxide nanoparticles in medicine and environmental remediation has led to concerns regarding exposure of these nanoparticles to the public. However, limited studies are available to evaluate their effects on the environment, in particular on plants and food crops. Here, we investigated the effects of positive (PC) and negative (NC) charged iron oxide (Fe₂O₃) nanoparticles (IONPs) on the physiology and reproductive capacity of Arabidopsis thaliana at concentrations of 3 and 25 mg/L. The 3 mg/L treated plants did not show evident effects on seeding and root length. However, the 25 mg/L treatment resulted in reduced seedling (positive-20% and negative-3.6%) and root (positive-48% and negative-negligible) length. Interestingly, treatment with polyethylenimine (PEI; IONP-PC coating) also resulted in reduced root length (39%) but no change was observed with polyacrylic acid (PAA; IONP-NC coating) treatment alone. However, treatment with IONPs at 3 mg/L did lead to an almost 5% increase in aborted pollen, a 2%-6% reduction in pollen viability and up to an 11% reduction in seed yield depending on the number of treatments. Interestingly, the treated plants did not show any observable phenotypic changes in overall size or general plant structure, indicating that environmental nanoparticle contamination could go dangerously unnoticed.

Pathogen associated molecular patterns (PAMPs) are signals detected by plants that activate basal defenses. One of these PAMPs is chitin, a carbohydrate present in the cell walls of fungi and in insect exoskeletons. Previous work has shown that chitin treatment of Arabidopsis thaliana induced defense-related genes in the absence of a pathogen and that the response was independent of the salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) signaling pathways. One of these genes is ATL9 ( = ATL2G), which encodes a RING zinc-finger like protein. In the current work we demonstrate that ATL9 has E3 ubiquitin ligase activity and is localized to the endoplasmic reticulum. The expression pattern of ATL9 is positively correlated with basal defense responses against Golovinomyces cichoracearum, a biotrophic fungal pathogen. The basal levels of expression and the induction of ATL9 by chitin, in wild type plants, depends on the activity of NADPH oxidases suggesting that chitin-mediated defense response is NADPH oxidase dependent. Although ATL9 expression is not induced by treatment with known defense hormones (SA, JA or ET), full expression in response to chitin is compromised slightly in mutants where ET- or SA-dependent signaling is suppressed. Microarray analysis of the atl9 mutant revealed candidate genes that appear to act downstream of ATL9 in chitin-mediated defenses. These results hint at the complexity of chitin-mediated signaling and the potential interplay between elicitor-mediated signaling, signaling via known defense pathways and the oxidative burst.

Chitin, a polymer of N-acetyl-d-glucosamine, is found in fungal cell walls but not in plants. Plant cells can perceive chitin fragments (chitooligosaccharides) leading to gene induction and defense responses. We identified a LysM receptor-like protein (LysM RLK1) required for chitin signaling in Arabidopsis thaliana. The mutation in this gene blocked the induction of almost all chitooligosaccharide-responsive genes and led to more susceptibility to fungal pathogens but had no effect on infection by a bacterial pathogen. Additionally, exogenously applied chitooligosaccharides enhanced resistance against both fungal and bacterial pathogens in the wild-type plants but not in the mutant. Together, our data indicate that LysM RLK1 is essential for chitin signaling in plants (likely as part of the receptor complex) and is involved in chitin-mediated plant innate immunity. The LysM RLK1-mediated chitin signaling pathway is unique, but it may share a conserved downstream pathway with the FLS2/flagellin- and EFR/EF-Tu-mediated signaling pathways. Additionally, our work suggests a possible evolutionary relationship between the chitin and Nod factor perception mechanisms due to the similarities between their potential receptors and between the signal molecules perceived by them.

Receptor-like kinases (RLKs) in plants are a large superfamily of proteins that are structurally similar. RLKs are involved in a diverse array of plant responses including development, growth, hormone perception and the response to pathogens. Current studies have focused attention on plant receptor-like kinases as an important class of sentinels acting in plant defense responses. RLKs have been identified that act in both broad-spectrum, elicitor-initiated defense responses and as dominant resistance (R) genes in race-specific pathogen defense. Most defense-related RLKs are of the leucine-rich repeat (LRR) subclass although new data are highlighting other classes of RLKs as important players in defense responses. As our understanding of RLK structure, activation and signaling has expanded, the role of the ubiquitin/proteasome system in the regulation of these receptors has emerged as a central theme.

Summary Chitin oligomers, released from fungal cell walls by endochitinase, induce defence and related cellular responses in many plants. However, little is known about chitin responses in the model plant Arabidopsis. We describe here a large-scale characterization of gene expression patterns in Arabidopsis in response to chitin treatment using an Arabidopsis microarray consisting of 2375 EST clones representing putative defence-related and regulatory genes. Transcript levels for 71 ESTs, representing 61 genes, were altered three-fold or more in chitin-treated seedlings relative to control seedlings. A number of transcripts exhibited altered accumulation as early as 10 min after exposure to chitin, representing some of the earliest changes in gene expression observed in chitin-treated plants. Included among the 61 genes were those that have been reported to be elicited by various pathogen-related stimuli in other plants. Additional genes, including genes of unknown function, were also identified, broadening our understanding of chitin-elicited responses. Among transcripts with enhanced accumulation, one cluster was enriched in genes with both the W-box promoter element and a novel regulatory element. In addition, a number of transcripts had decreased abundance, encoding several proteins involved in cell wall strengthening and wall deposition. The chalcone synthase promoter element was identified in the upstream regions of these genes, suggesting that pathogen signals may suppress the expression of some genes. These data indicate that Arabidopsis should be an excellent model to elucidate the mechanisms of chitin elicitation in plant defence.

Genomic-scale methods, such as cDNA microarrays, cDNA-AFLP analyses and proteomics are revolutionizing the study of plant-pathogen interactions, and are revealing a complex web of signaling cascades involved in plant defense responses. Recent studies have shown that responses to pathogens and environmental stresses are linked, suggesting that genes previously identified as stress-responsive may also play an active role in plant defense. As a result of proteomic analysis, proteins involved in early defense signaling are coming to light.

An unforeseen side-effect on plant growth in reduced oxygen is the loss of seed production at concentrations around 25% atmospheric (50 mmol mol-1 O2). In this study, the model plant Arabidopsis thaliana (L.) Heynh. cv. 'Columbia' was used to investigate the effect of low oxygen on ethylene biosynthesis during seed development. Plants were grown in a range of oxygen concentrations (210 [equal to ambient], 160, 100, 50 and 25 mmol mol-1) with 0.35 mmol mol-1 CO2 in N2. Ethylene in full-sized siliques was sampled using gas chromatography, and viable seed production was determined at maturity. Molecular analysis of ethylene biosynthesis was accomplished using cDNAs encoding 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase in ribonuclease protection assays and in situ hybridizations. No ethylene was detected in siliques from plants grown at 50 and 25 mmol mol-1 O2. At the same time, silique ACC oxidase mRNA increased three-fold comparing plants grown under the lowest oxygen with ambient controls, whereas ACC synthase mRNA was unaffected. As O2 decreased, tissue-specific patterning of ACC oxidase and ACC synthase gene expression shifted from the embryo to the silique wall. These data demonstrate how low O2 modulates the activity and expression of the ethylene biosynthetic pathway during seed development in Arabidopsis.

Plant culture in oxygen concentrations below ambient is known to stimulate vegetative growth, but apart from reports on increased leaf number and weight, little is known about development at subambient oxygen concentrations. Arabidopsis thaliana (L.) Heynh. (cv. Columbia) plants were grown full term in pre-mixed atmospheres with oxygen partial pressures of 2.5, 5.1, 10.1, 16.2, and 21.3 kPa O2, 0.035 kPa CO2 and the balance nitrogen under continuous light. Fully expanded leaves were harvested and processed for light and transmission electron microscopy or for starch quantification. Growth in subambient oxygen concentrations caused changes in leaf anatomy (increased thickness, stomatal density and starch content) that have also been described for plants grown under carbon dioxide enrichment. However, at the lowest oxygen treatment (2.5 kPa), developmental changes occurred that could not be explained by changes in carbon budget caused by suppressed photorespiration, resulting in very thick leaves and a dwarf morphology. This study establishes the leaf parameters that change during growth under low O2, and identifies the lower concentration at which O2 limitation on transport and biosynthetic pathways detrimentally affects leaf development. Grant numbers: NAG5-3756, NAG2-1020, NAG2-1375.