Asthma and odors: The role of risk perception in asthma exacerbation

Objective

Fragrances and strong odors have been characterized as putative triggers that may exacerbate asthma symptoms and many asthmatics readily avoid odors and fragranced products. However, the mechanism by which exposure to pure, non-irritating odorants can elicit an adverse reaction in asthmatic patients is still unclear and may involve both physiological and psychological processes. The aim of this study was to investigate how beliefs about an odor's relationship to asthmatic symptoms could affect the physiological and psychological responses of asthmatics.

Methods

Asthmatics classified as ‘moderate-persistent’, according to NIH criteria, were exposed for 15 min to a fragrance which was described either as eliciting or alleviating asthma symptoms. During exposure, participants were asked to rate odor intensity, perceived irritation and subjective annoyance while physiological parameters such as electrocardiogram, respiratory rate, and end tidal carbon dioxide (etCO₂) were recorded. Before, immediately after, and at 2 and 24 h post-exposure, participants were required to subjectively assess their asthma symptom status using a standardized questionnaire. We also measured asthma status at each of those time points using objective parameters of broncho-constriction (spirometry) and measures of airway inflammation (exhaled nitric oxide, FeNO).

Results

Predictably, manipulations of perceived risk altered both the quality ratings of the fragrance as well as the reported levels of asthma symptoms. Perceived risk also modulated the inflammatory airway response.

Conclusions

Expectations elicited by smelling a perceived harmful odor may affect airway physiology and impact asthma exacerbations.     

Perioperative Breast MRI Is Not Associated with Lower Locoregional Recurrence Rates in DCIS Patients Treated With or Without Radiation

Introduction

For women with ductal carcinoma in situ (DCIS) undergoing breast-conserving surgery (BCS), the benefit of magnetic resonance imaging (MRI) remains unknown. Here we examine the relationship of MRI and locoregional recurrence (LRR) and contralateral breast cancer (CBC) for DCIS treated with BCS, with and without radiotherapy (RT).

Methods

A total of 2,321 women underwent BCS for DCIS from 1997 to 2010. All underwent mammography, and 596 (26 %) also underwent perioperative MRI; 904 women (39 %) did not receive RT, and 1,391 (61 %) did. Median follow-up was 59 months, and 548 women were followed for ≥8 years. The relationship between MRI and LRR was examined using multivariable analysis.

Results

There were 184 LRR events; 5- and 8-year LRR rates were 8.5 and 14.6 % (MRI), respectively, and 7.2 and 10.2 % (no-MRI), respectively (p = 0.52). LRR was significantly associated with age, menopausal status, margin status, RT, and endocrine therapy. After controlling for these variables and family history, presentation, number of excisions, and time period of surgery, there remained no trend toward association of MRI and lower LRR [hazard ratio (HR) 1.18, 95 % confidence interval (CI) 0.79–1.78, p = 0.42]. Restriction of analysis to the no-RT subgroup showed no association of MRI with lower LRR rates (HR 1.36, 95 % CI 0.78–2.39, p = 0.28). No difference in 5- or 8-year rates of CBC was seen between the MRI (3.5 and 3.5 %) and no-MRI (3.5 and 5.1 %) groups (p = 0.86).

Conclusions

We observed no association between perioperative MRI and lower LRR or CBC rates in patients with DCIS, with or without RT. In the absence of evidence that MRI improves outcomes, the routine perioperative use of MRI for DCIS should be questioned.     

Functional Role of Glucose Metabolism,Osmotic Stress,and Sodium-Glucose Cotransporter Isoform-Mediated Transport on Na+/H+ Exchanger Isoform 3 Activity in the Renal Proximal Tubule

Na⁺-glucose cotransporter 1 (SGLT1)-mediated glucose uptake leads to activation of Na⁺-H⁺ exchanger 3 (NHE3) in the intestine by a process that is not dependent on glucose metabolism. This coactivation may be important for postprandial nutrient uptake. However, it remains to be determined whether SGLT-mediated glucose uptake regulates NHE3-mediated NaHCO₃ reabsorption in the renal proximal tubule. Considering that this nephron segment also expresses SGLT2 and that the kidneys and intestine show significant variations in daily glucose availability, the goal of this study was to determine the effect of SGLT-mediated glucose uptake on NHE3 activity in the renal proximal tubule. Stationary in vivo microperfusion experiments showed that luminal perfusion with 5 mM glucose stimulates NHE3-mediated bicarbonate reabsorption. This stimulatory effect was mediated by glycolytic metabolism but not through ATP production. Conversely, luminal perfusion with 40 mM glucose inhibited NHE3 because of cell swelling. Notably, pharmacologic inhibition of SGLT activity by Phlorizin produced a marked inhibition of NHE3, even in the absence of glucose. Furthermore, immunofluorescence experiments showed that NHE3 colocalizes with SGLT2 but not SGLT1 in the rat renal proximal tubule. Collectively, these findings show that glucose exerts a bimodal effect on NHE3. The physiologic metabolism of glucose stimulates NHE3 transport activity, whereas, supraphysiologic glucose concentrations inhibit this exchanger. Additionally, Phlorizin-sensitive SGLT transporters and NHE3 interact functionally in the proximal tubule.The kidney proximal tubule (PT) is the site where the reabsorption of approximately 70% of filtered sodium bicarbonate occurs. It is mainly performed by the Na⁺/H⁺ exchanger isoform 3 (NHE3).¹ The physiologic importance of NHE3 became evident after the development of NHE3 knockout mice, which presented mild metabolic acidosis and volume depletion with reduced BP, underscoring the role of NHE3 in volume homeostasis.²It has been shown that NHE3 physically and functionally interacts with dipeptidyl-peptidase IV, an enzyme that degrades and inactivates the incretin hormone glucagon like peptide-1.³ The inhibition of dipeptidyl-peptidase IV and the action of glucagon like peptide-1 were shown to inhibit NHE3 and promote natriuresis.^3–8 Additionally, various conditions and substances related to glucose metabolism, including diabetes, insulin, ATP, and glucose, modulate NHE3 in different tissues, showing a close relationship between carbohydrate homeostasis and NHE3 activity.^9–12Plasma glucose concentration is maintained at a constant level by a complex system, in which the kidneys perform a pivotal role by reabsorbing all the filtered glucose in the PT.¹³ In addition, the kidneys and liver are the only organs that express the glucose-6-phosphatase enzyme, thus enabling them to perform gluconeogenesis.^14,15 This enzyme is only expressed in the PT,¹⁶ highlighting the importance of this kidney segment in carbohydrate metabolism.It has been shown that the kidneys metabolize 20% of the glucose consumed in a meal.¹⁴ The PT has a low expression of hexokinase but the highest concentration and activity of glucose-6-phosphate dehydrogenase, indicating that this segment is able to metabolize glucose.^16,17 However, it is currently believed that the PT uses noncarbohydrate compounds as energy sources.¹⁷With relation to glucose uptake, the majority of filtered glucose is reabsorbed by the low-affinity, high-capacity sodium-glucose cotransporter isoform 2 (SGLT2). Some glucose is also reabsorbed by the high-affinity, low-capacity sodium-glucose cotransporter isoform 1 (SGLT1).¹³ Recently, SGLT2 inhibitors have been approved for the treatment of hyperglycemia in diabetic patients. The use of these inhibitors has been shown to decrease blood glucose, glycated hemoglobin, postprandial glucose, insulinemia, and body weight.^18–20The role of glucose uptake in the modulation of NHE3 activity in the small intestine has been extensively studied. Experiments have shown that glucose uptake through SGLT1 promotes intracellular NHE3-dependent alkalinization.^21–26 However, functional differences between intestinal and renal NaHCO₃ NHE3-mediated reabsorption have not been established. These two systems differ physiologically, because the gastrointestinal system is exposed to fluctuations in glucose concentration between the periods of fasting and after meals.¹³ The presence of large amounts of solutes within the intestinal cells after meals modulates membrane transporters, such as glucose transporter 2 (GLUT2) and NHE3,^21,27 an important process for nutrient absorption.Although the synergistic activation between SGLT1 and NHE3 has been observed in the intestine,²¹ it is not known if this process also occurs in the kidneys. Considering that the kidneys also express SGLT2 and the particularities of glucose availability in this organ, the goal of the present work was to determine the effect of glucose and SGLT activity on NHE3 in the renal PT.     

Facilitating surgical decisions for patients who are uncertain: a pilot surgical option process within an interdisciplinary functional restoration program

Background contextFor chronic pain patients, recovery may be slowed by indecisiveness over optional surgery. These patients may be delayed from participating in interdisciplinary functional restoration (FR), pending resolution of the surgical decision. Uncertainty about surgery or rehabilitation leads to delayed recovery. A surgical option process (SOP) was developed to permit patients with chronic disabling occupational musculoskeletal disorders to enter FR, make a final determination halfway through treatment, and return to complete rehabilitation after surgery, if surgery was elected.PurposeThis study assessed the frequency with which an FR program can resolve an uncertain surgical option. It also assessed program completion rate and 1-year post-program outcomes for subgroups that decline surgery, request and receive surgery, or request surgery but are denied by surgeon or insurance carrier.Study designRetrospective study of a consecutive cohort.Patient sampleA cohort of 44 consecutively treated chronic disabling occupational musculoskeletal disorder patients were admitted to an FR program and identified as candidates for a surgical procedure but were either ambivalent about undergoing surgery, had a difference of opinion by two or more surgeons, or were denied a surgical request by an insurance carrier. Patients attended half (10 full day visits) of an FR program before making their own final determination to pursue a request or decline surgery.Outcome measuresPatients were assessed on surgical requests and whether surgery was ultimately performed, program completion status after the surgical determination, demographic variables, and 1-year outcomes on work status, additional surgery, and other health utilization measures.MethodsPatients became part of the SOP on program entry and were included in the study if they participated in a surgical-decision interview halfway through the program. Those who elected to decline surgery (DS) completed the program without delay, but those requesting surgery were placed on hold from the program while consultation and preauthorization steps took place. Those requesting surgery, but denied (RSD), and those undergoing surgery (US) were given the opportunity to complete FR following postoperative physical therapy or resolution of the surgical re-evaluation process.ResultsThere were 32 DS patients (73%), indicating that a large majority of patients declined the surgery that was still being considered when offered participation in the SOP. Of the 12 patients wanting a surgery, there were four US patients who received surgery previously denied (9% of cohort), and eight RSD patients (18% of cohort). Patients from the DS group completed the FR program at an 88% rate, as did 75% of US patients. However, despite an opportunity to re-enter and complete rehab, only 50% of RSD patients completed the FR option. Overall, patients who persistently sought surgery, contrary to the recommendations of a surgeon, had poorer outcomes. These 1-year post-FR outcomes included lower return-to-work and work retention rates, with higher rates of treatment seeking from new providers (resulting in higher rates of post-discharge surgery) and higher rates of recurrent injury claims after work return.ConclusionsA SOP tied to participation in an interdisciplinary FR program resolves uncertainty regarding surgical options in a high proportion of cases, resulting in a large majority declining surgery and completing the FR program. Timely surgery is also promoted decisively when needed. Findings suggest that patients who persistently seek surgery, contrary to the recommendations of a surgeon, frequently fail to complete FR and have poorer outcomes overall.     

Impact of Margin Assessment Method on Positive Margin Rate and Total Volume Excised

Background

For breast-conserving surgery, the method of margin assessment that most frequently achieves negative margins without increasing the volume of tissue excised is uncertain. We examined our institutional experience with three different margin assessment methods used by six experienced breast surgeons.

Methods

Patients undergoing breast-conserving surgery for invasive carcinoma during July to December of a representative year during which each method was performed (perpendicular, 2003; tangential, 2004; cavity shave, 2011) were included. The effect of margin method on the positive margin rate at first excision and the total volume excised to achieve negative margins were evaluated by multivariable analysis, by surgeon, and by tumor size and presence of extensive intraductal component (EIC).

Results

A total of 555 patients were identified, as follows: perpendicular, 140; tangential, 124; and cavity shave, 291. The tangential method had a higher rate of positive margins at first excision than the perpendicular and cavity-shave methods (49, 15, 11 %, respectively; p < 0.0001). Median volumes to achieve negative margins were similar (55 ml perpendicular; 64 ml tangential; 62 ml cavity shave; p = 0.24). Four of six surgeons had the lowest rate of positive margins with the cavity-shave method, which was significant when compared to the tangential method (p < 0.0001) but not the perpendicular method (p = 0.37). The volume excised by the three methods varied by surgeon (p < 0.0001). The perpendicular method was optimal for T1 tumors without EIC; the cavity-shave method tended to be superior for T2–T3 tumors and/or EIC.

Conclusions

Although the cavity-shave method may decrease the rates of positive margins, its effect on volume is variable among surgeons and may result in an increase in the total volume excised for some surgeons and for small tumors without EIC.     

Pancreaticoduodenectomy for malignancies in children

Purpose

Malignant tumors of the common bile duct or of the pancreas head are uncommon in childhood [Perez EA, Gutierrez JC, Koniaris LG, Neville HL, Thompson WR, Sola JE. Malignant pancreatic tumors: incidence and outcome in 58 pediatric patients. J Pediatr Surg. 2009; Jan; 44 (1): 197–203]. With radical surgery being the standard cure for nonmetastatic diseases, pancreaticoduodenectomy (PD) is the best choice when the tumor is localized in the head of the pancreas, or in the lower portion of the common bile duct. The purpose of the present study is to describe five consecutive children managed by PD, and reviewing the particular aspects and results of this rare procedure in children.

Methods

Between 2007 and 2010, five patients (median age: 7 years) underwent PD for nonmetastatic malignant tumors. In two cases, PD was performed en bloc with a right hepatectomy in order to achieve the radical resection of a recurrent biliary sarcoma. Four patients benefited from a “pylorus-preserving” PD procedure. In two patients, resection of the portal vein and vascular reconstruction was performed, and in one case, an extended resection of the biliary ductal system was necessary.

Results

All resection margins were clear. The postoperative course was uneventful, with no pancreatic or biliary leakage in all of the patients. Oral refeeding was achieved by the eighth postoperative day. In two cases, a late revision of pancreatic–jejunal anastomosis was performed because of mild steatorrea and a suspected anastomotic stricture. Two of the patients, who were subsequently operated on second hand, for biliary sarcoma, died from the recurrence; while three of the others, with pancreatic malignancies, are alive and well, with a good functional outcome.

Conclusions

Surgical resection is the treatment of choice for tumors of the pancreatic head area. In the absence of regional or metastatic extension, the radicality of primary intervention is associated with favorable outcomes. Good functionality results were observed after the PD was limited to the head of the pancreas and subject to pylorus-preserving techniques.