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This lecture reviews the progress of the Association for Academic Surgery during the 1990s, a decade of sweeping innovations in technology, communication, and biomedical sciences; a well as a decade of transition in the demographics of surgical trainees; and a decade of new and previously unimagined possibilities for new directions in academic surgical careers. [ABSTRACT FROM AUTHOR]

Adipose tissue is an important energy depot and endocrine organ, and the degree of adiposity impacts the host response to infection. However, little is known regarding the mechanisms by which white adipose tissue (WAT) is lost acutely and then restored after the resolution of sepsis. Therefore, the signaling pathways governing protein synthesis, autophagy, apoptosis, and the ubiquitin-proteasome were investigated to identify potential mechanisms mediating the acute (24 h) loss of WAT after cecal ligation and puncture as well as the failure to replenish WAT during recovery (day 10). While whole body fat mass was decreased equally in pair-fed control and septic mice at 5 days after cecal ligation and puncture, fat mass remained 35% lower in septic mice at day 10. During sepsis-recovery, protein synthesis in epididymal WAT was increased compared with control values, and this increase was associated with an elevation in eukaryotic translation initiation factor (eIF)2Bε but no change in mammalian target of rapamycin complex 1 activity (eIF4E-binding protein-1 or S6 kinase 1 phosphorylation). Protein breakdown was increased during sepsis-recovery, as evidenced by the elevation in ubiquitin-proteasome activity. Moreover, indexes of autophagy (light chain 3B-II, autophagy-related protein 5/12, and beclin) were increased during sepsis-recovery and associated with increased AMP-activated kinase-dependent Ser555-phosphorylated Unc-51-like autophagy activating kinase-1. Apoptosis was increased, as suggested by the increased cleavage of caspase-3 and poly(ADP-ribose) polymerase. These changes were associated with increased inflammasome activity (increased NLR family, pyrin domain containing 3; TMS1; and caspase-1 cleavage) and the endoplasmic reticulum stress response (increased eIF2α and activating transcription factor-4) and browning (uncoupling protein-1) in epididymal WAT. Our data suggest that WAT stores remain depleted during recovery from sepsis due to sustained inflammation and elevations in protein and cellular degradation, despite the increase in protein synthesis. [ABSTRACT FROM AUTHOR]

Presents a study using reverse transcriptase-polymerase chain reaction to generate a 1,200-bp fragment specific to a basolateral isoform of the Na+-K+-Cl- cotransporter in the gastric fundus of Necturus maculosus. Findings suggesting that this basolateral transporter has a dominant and previously unsuspected role in secretion of HCL across the apical membrane.

At the 2007 Digestive Diseases Week, the Education Committee of the Society for Surgery of the Alimentary Tract sponsored a symposium entitled "Simulation in Gastrointestinal Surgery." Four panelists presented perspectives on the role of simulation in education and training of medical students and residents in operations of Gastrointestinal Surgery in the gastrointestinal surgeon's practice, in the certification of centers for training and maintenance of skills, and in the credentialing of surgeons in new procedures. The consensus of the panel is that over the next several years, simulation will play an expanding role in all of these spheres of the GI surgeon's activities. [ABSTRACT FROM AUTHOR]

Severe zinc deficiency is associated with an increased systemic inflammatory response and mortality after sepsis. However, the impact of mild zinc deficiency, which is more common in populations with chronic illnesses and sepsis, is unknown. In this study, we hypothesized that marginal dietary Zn deprivation (ZM) would amplify tissue inflammation and exacerbate the sepsis-induced decrease in muscle protein synthesis. Adult male C57BL/6 mice were fed a zinc-adequate (ZA) or ZM diet (30 or 10 mg Zn/kg, respectively) over 4 weeks, peritonitis was induced by cecal ligation and puncture (CLP), and mice were examined at either 24 h (acute) or 5 days (chronic) post-CLP. Acute sepsis decreased the in vivo rate of skeletal muscle protein synthesis and the phosphorylation of the mTOR substrate 4E-BP1. Acutely, sepsis increased TNF-α and IL-6 mRNA in muscle, and the increase in TNF-α was significantly greater in ZM mice. However, muscle protein synthesis and 4E-BP1 phosphorylation returned to baseline 5 days post-CLP in both ZA and ZM mice. Protein degradation via markers of the ubiquitin proteasome pathway was increased in acute sepsis, yet only MuRF1 mRNA was increased in chronic sepsis and ZM amplified this elevation. Our data suggest that mild zinc deficiency increases TNF-α in muscle acutely after sepsis but does not significantly modulate the rate of muscle protein synthesis. [ABSTRACT FROM AUTHOR]

Abstract: Prolactin receptor (PRL-R) activation regulates cell differentiation, proliferation, cell survival and motility of breast cells. Prolactin (PRL) and PRL-R over-expression are strongly implicated in breast cancer, particularly contributing to tumor growth and invasion in the more aggressive estrogen-receptor negative (ER−) disease. PRL-R antagonists have been suggested as potential therapeutic agents; however, mechanisms through which PRL-R antagonists exert their actions are not well-understood. Zinc (Zn) is a regulatory factor for over 10% of the proteome, regulating critical cell processes such as proliferation, cell signaling, transcription, apoptosis and autophagy. PRL-R signaling regulates Zn metabolism in breast cells. Herein we determined effects of PRL-R attenuation on cellular Zn metabolism and cell function in a model of ER-, PRL-R over-expressing breast cancer cells (MDA-MB-453). PRL-R attenuation post-transcriptionally increased ZnT2 abundance and redistributed intracellular Zn pools into lysosomes and mitochondria. ZnT2-mediated lysosomal Zn sequestration was associated with reduced matrix metalloproteinase 2 (MMP-2) activity and decreased invasion. ZnT2-mediated Zn accumulation in mitochondria was associated with increased mitochondrial oxidation. Our results suggest that PRL-R antagonism in PRL-R over-expressing breast cancer cells may reduce invasion through the redistribution of intracellular Zn pools critical for cellular function. [Copyright &y& Elsevier]

Abstract: Background: Experts become automated when performing surgery, making it difficult to teach complex procedures to trainees. Cognitive task analysis (CTA) enables experts to articulate operative steps and cognitive decisions in complex procedures such as laparoscopic appendectomy, which can then be used to identify central teaching points. Methods: Three local surgeon experts in laparoscopic appendectomy were interviewed using critical decision method-based CTA methodology. Interview transcripts were analyzed, and a cognitive demands table (CDT) was created for each expert. The individual CDTs were reviewed by each expert for completeness and then combined into a master CDT. Percentage agreement on operative steps and decision points was calculated for each expert. The experts then participated in a consensus meeting to review the master CDT. Each surgeon expert was asked to identify in the master CDT the most important teaching objectives for junior-level and senior-level residents. The experts'' responses for junior-level and senior-level residents were compared using a χ2 test. Results: The surgeon experts identified 24 operative steps and 27 decision points. Eighteen of the 24 operative steps (75%) were identified by all 3 surgeon experts. The percentage of operative steps identified was high for each surgeon expert (96% for surgeon 1, 79% for surgeon 2, and 83% for surgeon 3). Of the 27 decision points, only 5 (19%) were identified by all 3 surgeon experts. The percentage of decision points identified varied by surgeon expert (78% for surgeon 1, 59% for surgeon 2, and 48% for surgeon 3). When asked to identify key teaching points, the surgeon experts were more likely to identify operative steps for junior residents (9 operative steps and 6 decision points) and decision points for senior residents (4 operative steps and 13 decision points) (P < .01). Conclusions: CTA can deconstruct the essential operative steps and decision points associated with performing a laparoscopic appendectomy. These results provide a framework to identify key teaching principles to guide intraoperative instruction. These learning objectives could be used to guide resident level–appropriate teaching of an essential general surgery procedure. [Copyright &y& Elsevier]

Appendectomy is the most common non-gynecologic surgery performed during pregnancy. Little data exist on the accuracy of imaging studies in the diagnosis of appendicitis in pregnancy. The objective of this study was to evaluate the probability of ultrasound and computed tomography (CT) scan in diagnosing appendicitis in pregnancy, as reflected in the negative appendectomy rate. We retrospectively reviewed the charts of 86 pregnant women who underwent an appendectomy between January 1, 1997 and January 1, 2006. Patients were divided into three groups: clinical evaluation, ultrasound, and ultrasound followed by a CT scan. The clinical evaluation group had 13 patients, with a negative appendectomy rate of 54% (7/13). Fifty-five patients underwent an ultrasound alone, with a negative appendectomy rate 36% (20/55). In the ultrasound/CT group (n=13), the negative appendectomy rate was 8% (1/13). There was a significant reduction in the negative appendectomy rate in the ultrasound/CT scan group compared to clinical evaluation group (54 vs 8%, p<0.05). This reduction was not achieved in the ultrasound group when compared to the clinical evaluation group or the ultrasound/CT group (p=0.05). A significant reduction was achieved when the ultrasound/CT group was compared to the patients in the ultrasound only group who had a normal or inconclusive ultrasound (p<0.05). Our data documents a very high negative appendectomy rate in the pregnant patient. We recommend an ultrasound followed by a CT scan in patients with a normal or inconclusive ultrasound. [ABSTRACT FROM AUTHOR]

Background: Early postoperative hyperglycemia (POHG) is common and associated with poor postoperative outcomes. Currently, there is no systematic review and meta-analysis that addresses the knowledge gap of the incidence of POHG in surgical patients and that explores the associated risk factors and complications. The objective of this study will be to estimate the pooled incidence, risk factors, and clinical outcomes of early postoperative hyperglycemia in men and women globally. Methods: We designed and registered a study protocol for a systematic review and meta-analysis of studies reporting the incidence of postoperative hyperglycemia (POHG). We will search PubMed (MEDLINE), Scopus, Web of Science, EMBASE, Cochrane Library, OVID (HEALTH STAR), OVID (MEDLINE), and Joana Briggs Institute EBF Database (from inception onwards). Randomized controlled trials and observational cohort studies reporting the incidence of POHG and conducted in surgical patients will be included. No age, geographical location, study design, or language limits will be applied. The primary outcome will be the incidence of POHG. Secondary outcomes will be risk factors and clinical outcomes of POHG. Two reviewers will independently screen citations, full text articles, and abstract data, extract data, and evaluate the quality and bias of included studies. Discrepancies will be resolved through discussion or consultation with a third researcher. The risk of bias and study methodological quality of included studies will be evaluated by the appropriate Cochrane risk of bias tool for randomized trials and Newcastle-Ottawa Scale for cohort studies. If feasible, we will conduct random effects meta-analysis with a logit transformation of proportions. We will report the probability of postoperative hyperglycemia as a measure of incidence rate, relative risk ratios (RR), and 95% confidence intervals to report the effects of the risk factors and postoperative outcomes. Additional analyses will be conducted to explore the potential sources of heterogeneity (e.g., age, gender, geographical location, publication year, comorbidities, type of surgical procedure). The Egger test and funnel plots will be used to assess small study effects (publication bias). Discussion: This systematic review and meta-analysis will identify, evaluate, and integrate the evidence on the incidence, risk factors, and outcomes of early POHG in surgical patients. The results of this study can be used to identify populations which may be at particular risk for POHG. Future studies which use this information to better guide post-operative glycemic control in surgical patients could be considered. Systematic review registration: PROSPERO registration number CRD42020167138 [ABSTRACT FROM AUTHOR]

Suboptimal lactation is a common, yet underappreciated cause for early cessation of breastfeeding. Molecular regulation of mammary gland function is critical to the process lactation; however, physiological factors underlying insufficient milk production are poorly understood. The zinc (Zn) transporter ZnT2 is critical for regulation of mammary gland development and maturation during puberty, lactation, and post lactation gland remodeling. Numerous genetic variants in the gene encoding ZnT2 (SLC30A2) are associated with low milk Zn concentration and result in severe Zn deficiency in exclusively breastfed infants. However, the functional impacts of genetic variation in ZnT2 on key mammary epithelial cell functions have not yet been systematically explored at the cellular level. Here we determined a common mutation in SLC30A2/ZnT2 substituting serine for threonine at amino acid 288 (Thr288Ser) was found in 20% of women producing low milk volume (n = 2/10) but was not identified in women producing normal volume. Exploration of cellular consequences in vitro using phosphomimetics showed the serine substitution promoted preferential phosphorylation of ZnT2, driving localization to the lysosome and increasing lysosome biogenesis and acidification. While the substitution did not initiate lysosome-mediated cell death, cellular ATP levels were significantly reduced. Our findings demonstrate the Thr288Ser mutation in SLC30A2/ZnT2 impairs critical functions of mammary epithelial cells and suggest a role for genetic variation in the regulation of milk production and lactation performance. [ABSTRACT FROM AUTHOR]

Background: Minimally invasive surgical approaches for gastric adenocarcinoma are increasing in prevalence. Although recent studies suggest such approaches are associated with improvements in short-term outcomes, long-term outcomes have not been well studied. This study aimed to evaluate the impact of minimally invasive gastrectomy on long-term survival.Methods: The National Cancer Database (NCDB) was used to identify patients who underwent gastrectomy for adenocarcinoma between 2010 and 2015. Patient characteristics were stratified by open and minimally invasive approaches and compared using chi-square and t tests. Unadjusted survival functions were estimated using Kaplan-Meier methodology. Multivariable modeling of risks factors for survival was analyzed with Cox proportional hazard models. Covariate imbalance was controlled using propensity score matching.Results: The study included 17,449 patients who underwent gastrectomy. Cox proportional hazard modeling demonstrated that minimally invasive surgery improved survival (hazard ratio = 0.86, P < 0.0001). Predictors of worsened survival included community facility type, comorbidities, tumor size, extent of gastrectomy, clinical T and N staging (P < 0.0060 for all). After propensity score matching, minimally invasive surgery had a significantly improved survival at 5 years compared to an open approach, 51.9% versus 47.7% (P < 0.0001). Survival was not significantly different between propensity score-matched patients who received laparoscopic and robotic approaches (P = 0.2611).Conclusions: Minimally invasive approaches for gastric carcinoma are associated with improved long-term survival. There was no significant difference in survival when comparing laparoscopic to robotic gastrectomy. The mechanisms that drive these improvements deserve further investigation. [ABSTRACT FROM AUTHOR]

Background: The survival rates from breast cancer in Africa are poor and yet the incidence rates are on the rise. In this study, we hypothesized that, in Africa, a continent with great disparities in socio-economic status, race, tumor biology, and cultural characteristics, the survival rates from breast cancer vary greatly based on region, tumor biology (hormone receptor), gender, and race. We aimed to conduct the first comprehensive systematic review and meta-analysis on region, gender, tumor-biology and race-specific 5-year breast cancer survival rates in Africa and compared them to 20-year survival trends in the United States. Methods: We searched MEDLINE, EMBASE, and Cochrane Library to identify studies on breast cancer survival in African published before October 17, 2018. Pooled 5-year survival rates of breast cancer were estimated by random-effects models. We explored sources of heterogeneity through subgroup meta-analyses and meta-regression. Results were reported as absolute difference (AD) in percentages. We compared the survival rates of breast cancer in Africa and the United States. Findings: There were 54 studies included, consisting of 18,970 breast cancer cases. There was substantial heterogeneity in the survival rates (mean 52.9%, range 7–91%, I2 = 99.1%; p for heterogeneity <0.0001). Meta-regression analyses suggested that age and gender-adjusted 5-year survival rates were lower in sub-Saharan Africa compared to north Africa (AD: –25.4%; 95% CI: –34.9 - –15.82%), and in predominantly black populations compared to predominantly non-black populations (AD: –25.9%; 95% CI: 35.40 - –16.43%). Survival rates were 10 percentage points higher in the female population compared to male, but the difference was not significant. Progesterone and estrogen receptor-positive breast cancer subtypes were positively associated with survival (r = 0.39, p = 0.08 and r = 0.24, p = 0.29 respectively), but triple-negative breast cancer was negatively associated with survival. Survival rates are increasing over time more in non-black Africans (55% in 2000 versus 65% in 2018) compared to black Africans (33% in 2000 versus 40% in 2018); but, the survival rates for Africans are still significantly lower when compared to black (76% in 2015) and white (90% in 2015) populations in the United States. Conclusion: Regional, sub-regional, gender, and racial disparities exist, influencing the survival rates of breast cancer in Africa. Therefore, region and race-specific public health interventions coupled with prospective genetic studies are urgently needed to improve breast cancer survival in this region. [ABSTRACT FROM AUTHOR]

Background Mild dietary zinc (Zn) deficiency is widespread in human populations, but its influence on recovery after acute illness is poorly understood. In a mouse model of abdominal sepsis (cecal ligation puncture), systemic immune responses and liver metabolism were monitored in early (24 h) and late (5 d) phases, under control conditions and during mild dietary Zn restriction. Methods Mice were fed diets adequate or marginally deficient (ZM) in Zn (30 versus 10 mg zinc/kg diet) for 4 wk, before undergoing laparotomy alone (nonseptic control) or cecal ligation puncture (septic). Results Among nonseptic mice, the ZM state was not associated with differences in inflammation or metabolic responses. Among septic mice, mortality did not differ between the zinc adequate and ZM groups. In the early phase, the ZM state amplified increases in plasma interleukin (IL) 6, tumor necrosis factor alpha, and IL-10, while dampening the interferon gamma response. In the late phase, subtle but significant ZM-associated increases were observed in plasma IL-5 and interferon gamma levels and hepatic protein synthesis, the latter of which appeared to be mammalian target of rapamycin independent and was associated with increased hepatic tumor necrosis factor alpha messenger RNA content. Conclusions Without increasing mortality, the ZM state is associated with a more disordered acute systemic inflammatory response and persistence or enhancement of acute phase responses within the liver parenchyma. [ABSTRACT FROM AUTHOR]

Background Recent studies suggest that purified omega-3 fatty acids may attenuate acute inflammation and hasten the transition to healing. In this study, we tested the hypothesis that pretreatment with omega-3–rich fish oil (FO) would promote resolution of peritoneal inflammation through production of specific lipid mediators. Methods C57/BL6 mice were given a daily 200-μL oral gavage of saline (CTL) or FO (1.0-1.5 g/kg/d docosahexaenoic acid and 1.3-2.0 g/kg/d eicosapentaenoic acid) for 7 d before chemical peritonitis was induced with thioglycollate. Peritoneal lavage fluid was collected before induction and at days 2 and 4 after peritonitis onset. Prostaglandin E2 (PGE2), Leukotriene B4 (LTB4), Resolvin D1 (RvD1), and the composition of immune cell populations were examined in peritoneal lavage exudates. Cells harvested from the peritoneum were assessed for macrophage differentiation markers, phagocytosis, and lipopolysaccharide-induced cytokine secretion profiles (interleukin [IL]-6, IL-10, IL-1β, TNFα). Results The ratio of RvD1 to pro-inflammatory PGE2 and LTB4 was increased in the peritoneal cavity of FO-supplemented animals. FO induced a decrease in the number of monocytes in the lavage fluid, with no change in the number of macrophages, neutrophils, or lymphocytes. Macrophage phagocytosis and M1/M2 messenger RNA markers were unchanged by FO with the exception of decreased PPARγ expression. FO increased ex vivo TNFα secretion after stimulation with lipopolysaccharide. Conclusions Our findings provide evidence that nutraceutically relevant doses of FO supplements given before and during chemical peritonitis shift the balance of lipid mediators towards a proresolution, anti-inflammatory state without drastically altering the number or phenotype of local innate immune cell populations. [ABSTRACT FROM AUTHOR]

Background: Zinc (Zn) hyper-accumulates in breast tumors and malignant cell lines compared to normal mammary epithelium. The mechanisms responsible for Zn accumulation and the consequence of Zn dysregulation are poorly understood. Methods: Microarrays were performed to assess differences in the expression of Zn transporters and metallothioneins (MTs) in human breast tumors and breast cancer cell lines. Real-time PCR and immunoblotting were employed to profile Zn transporter expression in representative luminal (T47D), basal (MDA-MB-231), and non-malignant (MCF10A) cell lines. Zn distribution in human tumors was assessed by X-ray fluorescence imaging. Zn distribution and content in cell lines was measured using FluoZin-3 imaging, and quantification and atomic absorption spectroscopy. Functional consequences of ZnT2 over-expression in MDA-MB-231 cells including invasion, proliferation, and cell cycle were measured using Boyden chambers, MTT assays, and flow cytometry, respectively. Results: Gene expression profiling of human breast tumors and breast cancer cell lines identified subtype-specific dysregulation in the Zn transporting network. X-ray fluorescence imaging of breast tumor tissues revealed Zn hyper-accumulation at the margins of Luminal breast tumors while Zn was more evenly distributed within Basal tumors. While both T47D and MDA-MB-231 cells hyper-accumulated Zn relative to MCF10A cells, T47D cells accumulated 2.5-fold more Zn compared to MDA-MB-231 cells. FluoZin-3 imaging indicated that Zn was sequestered into numerous large vesicles in T47D cells, but was retained in the cytoplasm and found in fewer and larger, amorphous sub-cellular compartments in MDA-MB-231 cells. The differences in Zn localization mirrored the relative abundance of the Zn transporter ZnT2; T47D cells over-expressed ZnT2, whereas MDA-MB-231 cells did not express ZnT2 protein due to proteasomal degradation. To determine the functional relevance of the lack of ZnT2 in MDA-MB-231cells, cells were transfected to express ZnT2. ZnT2 over-expression led to Zn vesicularization, shifts in cell cycle, enhanced apoptosis, and reduced proliferation and invasion. Conclusions: This comprehensive analysis of the Zn transporting network in malignant breast tumors and cell lines illustrates that distinct subtype-specific dysregulation of Zn management may underlie phenotypic characteristics of breast cancers such as grade, invasiveness, metastatic potential, and response to therapy. [ABSTRACT FROM AUTHOR]

Zinc (Zn) regulates numerous cellular functions. Zn deficiency is common in females; ∼80% of women and 40% of adolescent girls consume inadequate Zn. Zn deficiency enhances oxidative stress, inflammation and DNA damage. Oxidative stress and inflammation is associated with breast disease. We hypothesized that Zn deficiency increases oxidative stress in the mammary gland, altering the microenvironment and architecture. Zn accumulated in the mammary glands of Zn deficient mice and this was associated with macrophage infiltration, enhanced oxidative stress and over-expression of estrogen receptor α. Ductal and stromal hypercellularity was associated with aberrant collagen deposition and disorganized e-cadherin. Importantly, these microenvironmental alterations were associated with substantial impairments in ductal expansion and mammary gland development. This is the first study to show that marginal Zn deficiency creates a toxic microenvironment in the mammary gland impairing breast development. These changes are consistent with hallmarks of potential increased risk for breast disease and cancer. [ABSTRACT FROM AUTHOR]

Targeted delivery of drugs and sensors into cells is an attractive technology with both medical and scientific applications. Existing delivery vehicles are generally limited by the complexity of their design, dependence on active transport, and inability to function within cellular compartments. Here, we developed self-assembled nanofibrous hydrogel fibers using a biologically inert, low-molecular-weight amphiphile. Self-assembled nanofibrous hydrogels offer unique physical/mechanical properties and can easily be loaded with a diverse range of payloads. Unlike commercially available E. coli membrane particles covalently bound to the pH reporting dye pHrodo, pHrodo encapsulated in self-assembled hydrogel-fibers internalizes into macrophages at both physiologic (37°C) and sub-physiologic (4°C) temperatures through an energy-independent, passive process. Unlike dye alone or pHrodo complexed to E. coli, pHrodo-SAFs report pH in both the cytoplasm and phagosomes, as well the nucleus. This new class of materials should be useful for next-generation sensing of the intracellular milieu. [ABSTRACT FROM AUTHOR]

Background and Aims: Recent work has suggested that Zn2+ plays a critical role in regulating acidity within the secretory compartments of isolated gastric glands. Here, we investigate the content, distribution and demand for Zn2+ in gastric mucosa under baseline conditions and its regulation during secretory stimulation. Methods and Findings: Content and distribution of zinc were evaluated in sections of whole gastric mucosa using X-ray fluorescence microscopy. Significant stores of Zn2+ were identified in neural elements of the muscularis, glandular areas enriched in parietal cells, and apical regions of the surface epithelium. In in vivo studies, extraction of the low abundance isotope, 70Zn2+, from the circulation was demonstrated in samples of mucosal tissue 24 hours or 72 hours after infusion (250 mg/kg). In in vitro studies, uptake of 70Zn2+ from media was demonstrated in isolated rabbit gastric glands following exposure to concentrations as low as 10 nM. In additional studies, demand of individual gastric parietal cells for Zn2+ was monitored using the fluorescent zinc reporter, fluozin-3, by measuring increases in free intracellular concentrations of Zn2+ {[Zn2+]i} during exposure to standard extracellular concentrations of Zn2+ (10 mM) for standard intervals of time. Under resting conditions, demand for extracellular Zn2+ increased with exposure to secretagogues (forskolin, carbachol/histamine) and under conditions associated with increased intracellular Ca2+ {[Ca2+]i}. Uptake of Zn2+ was abolished following removal of extracellular Ca2+ or depletion of intracellular Ca2+ stores, suggesting that demand for extracellular Zn2+ increases and depends on influx of extracellular Ca2+. Conclusions: This study is the first to characterize the content and distribution of Zn2+ in an organ of the gastrointestinal tract. Our findings offer the novel interpretation, that Ca2+ integrates basolateral demand for Zn2+ with stimulation of secretion of HCl into the lumen of the gastric gland. Similar connections may be detectable in other secretory cells and tissues. [ABSTRACT FROM AUTHOR]

Abstract: Omeprazole is a mainstay of therapy for gastroesophageal reflux disease (GERD) and gastritis, and is increasingly used as an over-the-counter remedy for dyspepsia. Omeprazole acts by selectively oxidizing thiol targets in the gastric proton pump, but it also appears to be toxic to the gastric mucosa. We hypothesized that omeprazole toxicity is due to non-specific oxidation of cell structures other than the proton pump, and tested the efficacy of antioxidants to prevent omeprazole-induced toxicity in isolated rabbit gastric glands. Toxicity was measured by uptake and converstion of calcein-AM, following three hours of exposure to omeprazole and a non-selective thiol-oxidant, monochloramine. Intracellular concentration of Zn2+ and the capacity to maintain luminal acidity were monitored using the fluorescent reporters fluozin-3 and Lysosensor DND-160, respectively. Both omeprazole and monochloramine caused marked reduction in cell viability. The toxicity of omeprazole was independent of monochloramine toxicity. The thiol reducing agent dithiothreitol protected gastric glands from injury. The oxidant scavenger Vitamin C also protected, and did not impair the anti-secretory effects of omeprazole. Thus, omeprazole toxicity appears to be oxidative and preventable with antioxidant therapy, including Vitamin C. Vitamin C may be a safe and efficacious addition to treatments requiring the use of PPIs. [Copyright &y& Elsevier]

Monochloramine (NH2Cl) is a potent, thiol-directed oxidant capable of oxidizing thiol (S-H) residues in a wide variety of proteins. Generated in the stomach by the interaction of bacterial and host products, monochloramine has been shown to dysregulate Ca2+ homeostasis and disrupt mucosal integrity. In this report, we show that monochloramine also leads to disturbances in intracellular free zinc concentration ([Zn2+]i) in the gastric gland of the rabbit and that the increased Zn2+ within the cell causes an independent decrease in cell viability. Changes in [Zn2+]i were measured by using the fluorescent reporter FluoZin-3, whereas cell viability was assessed by measuring the conversion of calcein-AM to fluorescent calcein, an assay that is not affected by intracellular oxidation state. Cell death was confirmed using propidium iodide and YO-PRO-1 dye uptake measurements. Our experiments demonstrate that [Zn2+]i is increased in gastric glands exposed to NH2Cl and that elevated [Zn2+]i decreases cell viability. Chelation of Zn2+ with tetrakis-(2-pyridylmethyl) ethylenediamine decreases the toxicity of NH2Cl, but only when administered concurrently. These findings suggest that the toxic effect of thiol oxidants present during chronic gastritis is partially due to dysregulation of [Zn2+]i early in the process and that zinc chelation can protect, but not rescue, gastric glands exposed to toxic doses of NH2Cl. [ABSTRACT FROM AUTHOR]

Secretory compartments of neurons, endocrine cells, and exocrine glands are acidic and contain high levels of labile Zn2t Previously, we reported evidence that acidity is regulated, in part, by the content of Zn2+ in the secretory [i.e., tubulovesicle (TV)] compartment of the acid-secreting gastric parietal cell. Here we report studies focusing on the mechanisms of Zn2+ transport by the TV compartment in the mammalian (rabbit) gastric parietal cell. Uptake of Zn2+ by isolated TV structures was monitored with a novel application of the fluorescent Zn2+ reporter N-(6-methoxy-8-quinolyl)-para-toluenesulfonamide (TSQ). Uptake was suppressed by removal of external AlP or blockade of H+-K+-ATPase that mediates luminal acid secretion. Uptake was diminished with dissipation of the proton gradient across the TV membrane, suggesting Zn2+/H+ antiport as the connection between Zn2+ uptake and acidity in the TV lumen. In isolated gastric glands loaded with the reporter fluozin-3, inhibition of H+-K+-ATPase arrested the flow of Zn2+ from the cytoplasm to the TV compartment and secretory stimulation with forskolin enhanced vectorial movement of cytoplasmic Zn2+ into the tubulovesicle/lumen (TV/L) cornpartment. Our findings suggest that Zn2+ accumulation in the TV/L compartment is physiologically coupled to secretion of acid. These findings offer novel insight into mechanisms regulating Zn2+ homeostasis in the gastric parietal cell and potentially other cells in which acidic subcellular compartments serve signature functional roles. [ABSTRACT FROM AUTHOR]

Background: Caspase-3, a pro-apoptotic enzyme, represents a class of proteins in which the active site contains reduced thiol (S-H) groups and is modulated by heavy metal cations, such as Zn2+. We explored the effects of the thiol oxidant monochloramine (NH2Cl) on caspase-3 activity within cells of isolated rabbit gastric glands. In addition, we tested the hypothesis that NH2Cl-induced alterations of caspase-3 activity are modulated by oxidant-induced accumulation of Zn2+ within the cytoplasm. Materials and methods: Isolated gastric glands were prepared from rabbit mucosa by collagenase digestion. Caspase-3 activity was measured colorimetrically in suspensions of healthy rabbit gastric glands, following exposure to various concentrations of NH2Cl with or without the zinc chelator TPEN [tetrakis-(2-pyridylmethyl)ethylene diamine] for 1 h, and re-equilibration in Ringer''s solution for 5 h. Conversion of procaspase-3 to active caspase-3 was monitored by Western blot. Results: Monochloramine inhibited caspase-3 activity in a dose-dependent fashion. At concentrations of NH2Cl up to 100 μm, these effects were prevented if TPEN was given concurrently and were partly reversed if TPEN was given 1 h later. Caspase-3 activity was preserved by concurrent treatment with a thiol-reducing agent, dithiothreitol. Conclusions: At pathologically relevant concentrations, NH2Cl impairs caspase-3 activity through oxidation of its thiol groups. Independently from its thiol oxidant effects on the enzyme, NH2Cl-induced accumulation of Zn2+ in the cytoplasm is sufficient to restrain endogenous caspase-3 activity. Our studies suggest that some bacterially generated oxidants, such as NH2Cl, impair host pathways of apoptosis through release of Zn2+ from endogenous pools. [Copyright &y& Elsevier]

In Helicobacter pylori-induced gastritis, oxidants are generated through the interactions of bacteria in the lumen, activated granulocytes, and cells of the gastric mucosa. In this study we explored the ability of one such class of oxidants, represented by monochloramine (NH2Cl), to serve as agonists of Ca2+ accumulation within the parietal cell of the gastric gland. Individual gastric glands isolated from rabbit mucosa were loaded with fluorescent reporters for Ca2+ in the cytoplasm (fura-2 AM) or intracellular stores (mag-fura-2 AM). Conditions were adjusted to screen out contributions from metal cations such as Zn2+, for which these reporters have affinity. Exposure to NH2CI (up to 200 µM) led to dose-dependent increases in intracellular Ca2+ concentration ([Ca2+]i), in the range of 200-400 nM above baseline levels. These alterations were prevented by pretreatment with the oxidant scavenger vitamin C or a thiol-reducing agent, dithiothreitol (DTT), which shields intracellular thiol groups from oxidation by chlorinated oxidants. Introduction of vitamin C during ongoing exposure to NH2CI arrested but did not reverse accumulation of Ca2+ in the cytoplasm. In contrast, introduction of DTT or N-acetylcysteine permitted arrest and partial reversal of the effects of NH2CI. Accumulation of Ca2+ in the cytoplasm induced by NH2CI is due to release from intracellular stores, entry from the extracellular fluid, and impaired extrusion. Ca2+-handling proteins are susceptible to oxidation by chloramines, leading to sustained increases in [Ca2+]i. Under certain conditions, NH2CI may act not as an irritant but as an agent that activates intracellular signaling pathways. Anti-NH2Cl strategies should take into account different effects of oxidant scavengers and thiol-reducing agents. [ABSTRACT FROM AUTHOR]

During acute exacerbations of inflammatory bowel diseases, oxidants are generated through the interactions of bacteria in the lumen, activated granulocytes, and cells of the colon mucosa. In this study we explored the ability of one such class of oxidants, represented by monochloramine (NH2CI), to serve as agonists of Ca2+ and Zn2+ accumulation within the colonocyte. Individual colon crypts prepared from Sprague-Dawley rats were mounted in perfusion chambers after loading with fluorescent reporters fura 2-AM and fluozin 3-AM. These reporters were characterized, in situ, for responsiveness to Ca2+ and Zn2+ in the cytoplasm. Responses to different concentrations of NH2Cl (50, 100, and 200 µM) were monitored. Subsequent studies were designed to identify the sources and mechanisms of NH2Cl-induced increases in Ca2+ and Zn2+ in the cytoplasm. Exposure to NH2CI led to dose-dependent increases in intracellular Ca2+ concentration ([Ca2+]i) in the range of 200-400 nM above baseline levels. Further studies indicated that NH2CI-induced accumulation of Ca2+ in the cytoplasm is the result of release from intracellular stores and basolateral entry of extracellular Ca2+ through store-operated channels. In addition, exposure to NH2CI resulted in dose-dependent and sustained increases in intracellular Zn2+ concentration ([Zn2+]i) in the nanomolar range. These alterations were neutralized by dithiothreitol, which shields intracellular thiol groups from oxidation. We conclude that Ca2+- and Zn2+-handling proteins are susceptible to oxidation by chloramines, leading to sustained, but not necessarily toxic, increases in [Ca2+]i and [Zn2+]i. Under certain conditions, NH2CI may act not as a toxin but as an agent that activates intracellular signaling pathways. [ABSTRACT FROM AUTHOR]

It is well recognized that ileostomy patients suffer from chronic depletion of Na+ through the stoma effluent. In this study we evaluated the effects of ileostomy on messenger RNA levels that encode different Na+/H+ exchanger isoforms (NHE-2 and NHE-3). Loop ileostomies were created in Sprague-Dawley rats. Segments of diverted ileum were harvested for quantitation of mRNA levels encoding these isoforms and the Na+/K+ ATPase in mucosal scrapings and for immunofluorescence microscopy, specifically of the NHE-3 protein. Our studies indicate that as early as 8 days after diversion, NHE-3 gene expression is selectively attenuated in poststomal ileal mucosa. Mucosal morphology remains undisturbed, and the distribution of protein expression along the crypt/villus axis is not altered. Infusion of Na+ or the enterocyte nutrient, glutamine, into the lumen of the diverted segment restores or even augments mRNA levels for NHE-3, again without altering the histologic appearance or distribution of the protein along the crypt/villus axis. These effects are specific because nonpolar osmolytes (mannitol) and related organic nutrients not specific for the enterocyte (i.e., butyrate) have no effect on mRNA levels of NHE-3. Further work is required to understand how the early changes in mRNA contribute to mucosal function and response to luminal diversion. (J Gastrointest Surg 2002;6:387–395.) [ABSTRACT FROM AUTHOR]

We recently proposed that extracellular Ca2+ ions participate in a novel form of intercellular communication involving the extracellular Ca2+-sensing receptor (CaR). Here, using Ca2+-selective microelectrodes, we directly measured the profile of agonist-induced [Ca2+]ext changes in restricted domains near the basolateral or luminal membranes of polarized gastric acid-secreting cells. The Ca2+-mobilizing agonist carbachol elicited a transient, La3+-sensitive decrease in basolateral [Ca2+] (average &ap;250 μM, but as large as 530 μM). Conversely, carbachol evoked an HgCl2- sensitive increase in [Ca2+] (average &ap;400 μM, but as large as 520 μM) in the lumen of single gastric glands. Both responses were significantly reduced by pretreatment with sarco-endoplasmic reticulum Ca2+ ATPase (SERCA) pump inhibitors or with the intracellular Ca2+ chelator BAPTA-AM. Immunofluorescence experiments demonstrated an asymmetric localization of plasma membrane Ca2+ ATPase (PMCA), which appeared to be partially co-localized with CaR and the gastric H+/K+-ATPase in the apical membrane of the acid-secreting cells. Our data indicate that agonist stimulation results in local fluctuations in [Ca2+]ext that would be sufficient to modulate the activity of the CaR on neighboring cells. [ABSTRACT FROM AUTHOR]

Agonist-evoked, intracellular Ca[sup 2+]-signalling events are associated with active extrusion of Ca[sup 2+] across the plasma membrane, implying a local increase in Ca[sup 2+] concentration ([Ca[sup 2+]]) at the extracellular face of the cell. The possibility that these external [Ca[sup 2+]] changes may have specific physiological functions has received little consideration in the past. Here we show that, at physiological ambient [Ca[sup 2+]], Ca[sup 2+] mobilization in one cell produces an extracellular signal that can be detected in nearby cells expressing the extracellular Ca[sup 2+]-sensing receptor (CAR), a cell-surface receptor for divalent cations with a widespread tissue distribution. The CaR may therefore mediate a universal form of intercellular communication that allows cells to be informed of the Ca[sup 2+]-signalling status of their neighbours. [ABSTRACT FROM AUTHOR]

Focuses on the localization and identification of extracellular Ca2+ -sensing receptor in rat intestine. Methodologies and materials used; Results of experiments conducted; Discussion on the topic; Further information.

Examines the genetic properties and localization of extracellular Ca2+-sensing receptor (CaR) in small and large intestine of rats. Distribution of CaR mRNA in small and large intestine by RT-PCR; Distribution of CaR mRNA in various intestinal segments by Northern blot analysis; Immunocytochemistry of CaR in small and large intestine.

Background: The reported incidence rates of sexual dysfunction (SD) and pain with sexual activity (PSA) after inguinal hernia repair in males vary considerably. This meta-analysis explores the rates of SD and PSA after different surgical and anesthesia types to understand patient risk after inguinal hernia repair.Study Design: We performed a systematic review and meta-analysis using Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines to search 3 databases (EMBASE, MEDLINE, and Cochrane Library). We identified retrospective, prospective, and randomized controlled trial studies, published on or before March 1, 2019, reporting on SD and PSA after inguinal hernia repair. We used random-effects models to calculate pooled estimates of incidence rates of SD and PSA after inguinal hernia repair. Subgroup meta-analyses and meta-regression were used to explore sources of variation.Results: A total of 4,884 patients from 12 studies were identified. Study-level median age at the time of repair was 52.3 years old, and study-level median follow-up was 10.5 months. Definitions of SD and PSA focused on completion of intercourse for the former and pain with erection/ejaculation for the latter. The overall incidence of new-onset, postoperative SD was 5.3% (95% CI 3.6% to 7.9%) and of PSA was 9.0% (95% CI 5.8% to 13.6%). Rates of SD associated with minimally invasive surgical (MIS) and open repair were, respectively, 7.8% (95% CI 5.4% to 11.3%) and 3.7% (95% CI 2.0% to 6.8%); rates of PSA were 7.4% (95% CI 4.7% to 11.5%) and 12.5% (95% CI 6.4% to 23.3%), respectively.Conclusions: Sexual dysfunction and PSA are not rare after inguinal hernia repair. They should be included in preoperative discussions and as standard metrics in reporting outcomes of repair in large cohorts or trials. [ABSTRACT FROM AUTHOR]

Background: For patients undergoing major abdominal operations, acute postoperative hyperglycemia (POHG) is associated with suboptimal outcomes and higher costs of care. This study was performed to determine whether CT-derived indices of nonalcoholic fatty liver disease (hepatic steatosis) or visceral adiposity may serve as predictors of POHG and its consequences in such patients.Study Design: We reviewed records and preoperative abdominal CT images of 129 patients undergoing complex open ventral hernia repair (cVHR) from 2012 to 2016, with 90-day follow-up. Univariate and multivariate regressions were performed to estimate associations between CT-detected steatosis or visceral adiposity with POHG (serum glucose > 140 mg/dL within 48 hours), surgical site occurrence (SSO), and subsequent interventions (SSO-I).Results: Type-2 diabetes (T2D) was present in 23% and POHG in 52%; SSO events occurred in 28% and SSO-I in 21%. Highest-effect associations with POHG were observed for T2D (odds ratio [OR] 21.54; 95% CI 4.85, 95.58), hepatic steatosis (OR 2.20, 95% CI 1.07, 4.52), and waist circumference-to-height ratio (WCHR > 0.65; OR 2.37, 95% CI 1.16, 4.83). After multivariate analysis, the effects of T2D (OR 16.73; CI 5.42, 73.87; p < 0.0001) and steatosis (OR 2.55; CI 1.17, 5.69; p = 0.02) remained independently associated with POHG. Independent associations with SSO were observed for steatosis (OR 3.31; CI 1.41, 8.06; p = 0.007), POHG (OR 2.85; CI 1.17, 7.38; p = 0.024), and WCHR (OR 2.68; CI 1.11, 6.85; p = 0.03).Conclusions: Image-based indices of chronic metabolic disturbance in the liver and adipose tissues may offer novel opportunities for identifying patients at risk for POHG and those who would benefit from preoperative metabolic optimization. [ABSTRACT FROM AUTHOR]

Mammary gland involution is the most dramatic example of physiological cell death. It occurs through an initial phase of lysosomal-mediated cell death (LCD) followed by mitochondrial-mediated apoptosis. Zinc (Zn) activates both LCD and apoptosis in vitro. The Zn transporter ZnT2 imports Zn into vesicles and mitochondria and ZnT2-overexpression activates cell death in mammary epithelial cells (MECs). We tested the hypothesis that ZnT2-mediated Zn transport is critical for mammary gland involution in mice. Following weaning, ZnT2 abundance increased in lysosomes and mitochondria, which paralleled Zn accumulation in each of these organelles. Adenoviral expression of ZnT2 in lactating mouse mammary glands in vivo increased Zn in lysosomes and mitochondria and activated LCD and apoptosis, promoting a profound reduction in MECs and alveoli. Injection of TNFα, a potent activator of early involution, into the mammary gland fat pads of lactating mice increased ZnT2 and Zn in lysosomes and activated premature involution. Exposure of cultured MECs to TNFα redistributed ZnT2 to lysosomes and increased lysosomal Zn, which activated lysosomal swelling, cathepsin B release, and LCD. Our data implicate ZnT2 as a critical mediator of cell death during involution and importantly, that as an initial involution signal, TNFα redistributes ZnT2 to lysosomes to activate LCD. [ABSTRACT FROM AUTHOR]