Comparing complex perspectives on obesity drivers: action-driven communities and evidence-oriented experts

INTRODUCTION

The Foresight obesity map represents an expert-developed systems map describing the complex drivers of obesity. Recently, community-led causal loop diagrams have been developed to support community-based obesity prevention interventions. This paper presents a quantitative comparison between the Foresight obesity systems map and a community-developed map of the drivers of obesity.

METHODS

Variables from a community-developed map were coded against the thematic clusters defined in the Foresight map to allow comparison of their sizes and strength of adjoining causal relationships. Central variables were identified using techniques from network analysis. These properties were compared to understand the similarities and differences between the systems as defined by the two groups.

RESULTS

The community map focused on environmental influences, such as built physical activity environment (18% of variables) and social psychology (38%). The Foresight map's largest cluster was physiology (23%), a minimal focus in the community map (2%). Network analysis highlighted media and available time within both maps, but variables related to school and sporting club environments were unique to the community map.

CONCLUSION

Community stakeholders focus on modifiable social and environmental drivers of obesity. Capturing local perspectives is critical when using systems maps to guide community-based obesity prevention.

Neurodevelopmental Outcomes Following Extensive Cardiopulmonary Resuscitation in the Delivery Room for Infants Born <29 Weeks’ Gestational Age

BACKGROUND: Neurodevelopmental outcomes of preterm infants who receive extensive CPR (ECPR), defined as chest compression with or without epinephrine in the delivery room, remain unclear.

OBJECTIVES: To compare the neurodevelopmental outcomes of preterm infants admitted to Canadian NICUs requiring ECPR versus those who did not require ECPR in the delivery room.

DESIGN/METHODS: Preterm infants born at <29 weeks GA between January 1, 2010 and September 30, 2011 and evaluated at CNFUN centers were retrospectively evaluated. The primary outcome was a composite of death or neurodevelopmental impairment (NDI) at 18-21 months CA defined as presence of any one or more of the following: definitive cerebral palsy or Bayley- III cognitive, language, motor scores <85 on any one of the components or hearing impairment or visual impairment. Demographic factors, neurodevelopmental status including Bayley III cognitive, language and motor scores and sensory impairments were compared between the ECPR and the no ECPR group using univariate and multivariate analyses. RESULTS: Of 2488 eligible infants, 197 (7.9%) received ECPR. 83% of surviving infants had follow-up data. Demographic and outcomes data are summarized below in Table 1 and 2 respectively.

Effect of 10%, 30%, and 60% body weight traction on the straight leg raise test of symptomatic patients with low back pain

STUDY DESIGN

Single group test-retest repeated measures.

OBJECTIVES

To determine the effects of lumbar traction with 3 different amounts of force (10%, 30% and 60% body weight) on pain-free mobility of the lower extremity as measured by the straight leg raise (SLR) test.

BACKGROUND

There are several recommendations on how lumbar traction should be performed, but the duration, frequency, force, and type of technique to be applied differ among the sources.

METHODS AND MEASURES

Ten subjects with subjective complaints of low back pain or radicular symptoms with a positive unilateral SLR test below 45 degrees participated in this study. The pain-free mobility of the lower extremity in the SLR test position was measured prior to and immediately following 5 minutes of static traction in the supine position. Random assignment in the order of the amount of applied traction was implemented.

RESULTS

The straight leg raise measurements were found to be significantly greater immediately following 30% and 60% of body weight traction as compared to pretraction and 10% of body weight traction. The mean (SD) SLR measurements were pretraction (24.1 degrees +/- 13.0), 10% of body weight traction (27.4 degrees +/- 14.5), 30% of body weight traction (34.0 degrees +/- 14.3), 60% of body weight traction (36.5 degrees +/- 15.8).

CONCLUSIONS

The results of this study indicate that traction in this group of patients improved the mobility of the lower extremity during the SLR test. Both 30% and 60% of body weight tractions were shown to be effective for increasing motion beyond pretraction levels.

Maillard reactions in lens proteins: methylglyoxal-mediated modifications in the rat lens

The nonenzymatic Maillard reaction is thought to contribute to aging and cataract formation in the lens. As levels of methylglyoxal (MG) and glutathione (GSH) affect the reaction, we examined the relationship of these factors and determined the effect of a glyoxalase I inhibitor on the Maillard reaction. Rat lens cultures were maintained for up to 3 days in TC-199 medium with or without 20 m m glyceraldehyde (GLD) and 250 microm S-[N-hydroxy-N-(4-chlorophenyl) carbamoyl] glutathione diethyl ester (HCCG diester). We measured GSH, MG, D-lactate, glyoxalase I activity, immunoreactive MG-derived advanced glycation endproducts (MG-AGEs) and imidazolysine in organ cultured rat lenses. In vitro experiments with isolated rat lens proteins revealed that HCCG alone inhibited glyoxalase I activity in a dose-dependent manner. In organ cultured rat lens protein, GLD increased MG levels 24-fold, and the addition of HCCG diester further increased it by about two-fold. GSH levels fell sharply in the presence of GLD and this was prevented to some extent by the presence of HCCG diester. D-lactate production in the lens was suppressed by HCCG diester treatment. Dialysed lens proteins retained glyoxalase I activity, indicating that the enzyme was unaltered during incubation. MG-AGEs and imidazolysine levels were significantly higher (P<0.05) in GLD-treated lenses, but a combination of HCCG diester and GLD lowered immunoreactive MG-AGEs and imidazolysine levels compared to GLD alone. HCCG had no significant effect on MG-AGE formation in lens proteins incubated with GLD or MG. We conclude that exogenous GLD enhances MG and MG-AGE levels in the rat lens and that this increase is accompanied by a loss in GSH. In addition, inhibition of glyoxalase I promotes MG accumulation.

Endothelial cell adaptation to chronic thrombosis

BACKGROUND

The autogenous vein graft has proven to be the most durable conduit in lower extremity vascular bypass grafts. Failures due to thrombosis, intimal hyperplasia, and progression of atherosclerotic disease commonly plague the vascular surgeon. Part of the ability of vein grafts to provide a nonthrombogenic surface relies on the capability of the endothelial cell to produce prostacyclin, a potent vasodilator and inhibitor of platelet aggregation. Once a graft fails and thromboses, little is known as to the effects of the thrombus on the function and morphology of endothelial cells. Earlier studies by this laboratory demonstrated the ability of arterialized canine vein grafts to recover function after 5 days of exposure to thrombus. This investigation sought to explore the limits of endothelial cell viability and recovery to extended periods of thrombosis.

METHODS

Using a canine model of arterialized vein grafts, prostacyclin production (measured as 6-keto-PGF1a) was assessed in an ex vivo perfusion system from grafts exposed to thrombus for 10 days (group I) and 20 days (group II). Both groups underwent thrombectomy and a recovery period of 30 days. The grafts were perfused with Hanks' balanced salt solution and samples were obtained at 5 and 30 minutes to determine prostacyclin levels. Arachidonic acid was then added to a new perfusate of Hanks' solution and samples were again obtained at 5 and 30 minutes. Results were expressed as PGF/graft area (cm2/min). Representative samples of each graft underwent scanning electron microscopy.

RESULTS

Without arachidonic acid, prostacyclin production of group II (20 day) grafts was greater than group I (10 day) grafts at 5 minutes of perfusion (4.31 versus 2.42, P = 0.08) and at 30 minutes (1.86 versus 0.95, P = 0.02). In response to the addition of arachidonic acid both groups increased prostacyclin production (group I, P = 0.004; group II, P = 0.12). A comparison was made between prostacyclin production at baseline and after addition of arachidonic acid. Group I grafts demonstrated a greater percent increase in prostacyclin production compared to group II (385% versus 229%, P = 0.01). Scanning electron microscopy showed no differences in endothelial coverage between the study groups.

CONCLUSIONS

These results demonstrate that although endothelial cells are able to recover a basal level of prostacyclin production, the response to substrate stimulation diminishes with increased exposure time to thrombus. This diminished response may be important in understanding the ability of vein grafts to survive after a period of thrombosis.

The effect of thrombus on the vascular endothelium of arterialized vein grafts

BACKGROUND

It is known that vein grafts can be salvaged by clot removal, but patency rates are diminished. This study was designed to determine the effects of thrombus on vascular endothelium and the ability of the endothelium to recover normal function.

METHODS

Thirty external jugular vein grafts were placed as bilateral femoral artery interposition grafts in 15 mongrel dogs and allowed to arterialize for a period of at least 12 weeks. Six control grafts were not exposed to thrombus (C-NT). Six other control grafts were exposed to thrombus for 7 days and removed, ie, allowed no in vivo recovery (C-T). The remaining 18 grafts in 9 canines were exposed to autologous thrombus for 5 days and then flow was restored. The right femoral graft was removed 7 days after thrombectomy and the left removed 30 days after thrombectomy. At the time of removal, the grafts were perfused with a balanced salt solution alone and then with arachidonic acid added to the same volume of the salt solution. Perfusates were collected at 5, 15, and 30 minutes. These perfusates were assayed for the presence of 6-keto-prosglandin F1 alpha (6-keto-PGF1(1 alpha)), a metabolite of prostacyclin (PGI2). Over the 30-day recovery period, the amounts of 6-keto-PGF1(1 alpha) produced with and without arachidonic acid added were compared to assess endothelial response. Electron micrographs of the endothelium of all vein grafts were compared to the assay findings.

RESULTS

When arachidonic acid was added to the perfusion system, there was a several fold increase in the production of 6-keto-PGF1(1 alpha) over baseline in all grafts allowed recovery. Grafts (C-T) that were allowed no in vivo recovery had no response to arachidonic acid. Ratios of 6-keto-PGF1(1 alpha) production with arachidonic acid stimulation to 6-keto-PGF1(1 alpha) production without stimulation were calculated to compare endothelial function. The electron micrographs showed the vascular endothelium to be severely injured after contact with thrombus, but recovered by 7 days.

CONCLUSIONS

This study suggests that the endothelium of canine vein grafts is injured by contact with thrombus for 5 days but can recover structure and function. This recovery is detectable at 7 days post-thrombectomy.

Flurbiprofen (Ansaid) cross-sensitivity in an aspirin-sensitive asthmatic patient

Flurbiprofen (Ansaid) is a newly released nonsteroidal antiinflammatory drug (NSAID) that is a potent inhibitor of prostaglandin synthesis. We report the first case (to our knowledge) of a flurbiprofen-induced asthmatic reaction confirmed by single-blind oral challenges. Cross-sensitivity and cross-desensitization between aspirin (ASA) and flurbiprofen were also demonstrated in this patient with rhinosinusitis and asthma, thus reinforcing the observation that NSAIDs capable of cyclooxygenase inhibition crossreact with ASA in producing characteristic respiratory reactions.

Treatment of acute vascular occlusions with intra-arterial urokinase

This study reviewed 57 patients with 71 vascular occlusions treated with urokinase from 1985 to 1988. Of these patients, 89% were candidates for urgent surgery. Total clot lysis was achieved in 73% of cases. The success rate rose with increasing experience (p less than 0.05), and recent occlusions had more favorable outcomes than older ones (p less than 0.05). The length and type of occluded conduit (graft or vessel), age, sex, other medical conditions, and concurrent use of heparin had no influence on success. Of 18 cases successfully lysed and not subjected to any adjunctive therapy directed at the cause of occlusion, 9 (50%) reoccluded within 1 to 88 days (mean: 25 days). Cases successfully treated with thrombolysis and surgery or dilation of the causative stenosis had poor 1-year patencies: 17%, 20%, and 55% for vein grafts, prosthetic grafts, and native arteries, respectively. With additional urokinase treatments, surgical operations, and percutaneous procedures, 1-year patencies were 22%, 45%, and 65%, respectively.

Home oxygen therapy. Outcome of infants discharged from NICU on continuous treatment

Forty-four oxygen-dependent infants were discharged home in oxygen from an NICU during an 8-year period. Survivors were followed for 3 years. The infants' discharge diagnoses were bronchopulmonary dysplasia (BPD) (39), sleep apnea (2), and congenital cardiac defects (3). The five infants who had diagnoses other than BPD all died, but 34 of 39 infants with BPD survived. Supplemental oxygen was discontinued at a mean age of 13.4 months. The infants with BPD experienced health, growth, nutritional, neurodevelopmental and sensory problems that necessitated frequent rehospitalizations and utilization of a variety of medical and support services.

Alprazolam reduces stress-induced mortality in cardiomyopathic hamsters

These experiments examined the role of several variables involved in the production of serious, stress-induced disease. Experiments 1 and 2 indicated that stress may not be medically dangerous except in animals with a predisposition or vulnerability to disease. Repeated exposure to cold-immobilization produced no detectable ill effects in healthy hamsters, but it was lethal for cardiomyopathic hamsters (CMHs). Experiment 3 showed that stressor intensity was also critical to the outcome of stress. CMHs succumbed when they were stressed in the supine position, but not when they were immobilized in the less stressful prone position. In Experiment 4, we attempted to reduce the stressfulness of cold-immobilization with the anxiolytic alprazolam. Alprazolam effectively blocked stress-induced mortality. In addition, we found that poststress body temperature was a crude predictor of an animal's ability to cope with stress. Alprazolam prevented CMHs from developing stress-induced hypothermia.

Aging, stress, and chronic disease interact to suppress plasma testosterone in Syrian hamsters

The effects of old age, chronic disease, and stress on testicular function were examined in Syrian hamsters living on a 12-hr photoperiod. Plasma testosterone concentrations and testes weights were maintained in healthy hamsters 16-19 months of age, but chronic stress decreased plasma testosterone in these old hamsters and not in younger ones (8-11 months of age). Chronic disease in the form of congestive heart failure (CHF) in cardiomyopathic hamsters also decreased plasma testosterone and testes weights, although it is not clear what aspects of this disease affected testicular function. There was an interaction between disease and stress, in that chronic stress produced lower plasma testosterone and testes weights in hamsters with heart failure than in age-matched stressed, healthy hamsters. It appears that younger hamsters can maintain reproductive function during stress, but older ones may not be able to do so. Congestive heart failure in hamsters clearly impairs normal reproductive function by itself; it also makes them more susceptible to stress, so that combining stress and disease results in almost complete suppression of plasma testosterone levels.

Adrenal hormonal indices of stress in laboratory rats

When individual rats were exposed to different intensities of a stressor, foot shock, plasma catecholamines were found to be sensitive and reliable indices of the stress. Plasma corticosterone did not perform as well. Similarly, levels of both plasma epinephrine and norepinephrine correlated highly significantly with a behavioral measure of the degree of stress--namely, the amount of movement about the cage seen during the 30 sec shock period. Importantly, this behavioral measure was as sensitive and reliable an index of stress as the catecholamines. However, use of either the catecholamines or this behavioral measure as a clinically useful measure of the level of stress was limited by the fact that their responses to the stressor were extremely short-lived. Nonetheless, because the catecholamines reliably and sensitively track the intensity of a stressor, they appear to be a good visceral measure of stress, perhaps the best currently available. But the behavioral concomitants of stress are quickly and easily quantifiable and present a wide range to study, starting with alerting, through a progression of more aroused motor activity, and ending with fight-flight. Because the behavioral concomitants of stress have not been as intensively studied as the endocrine ones, we believe that future efforts to find a clinically useful index of stress will be rewarded by a refocussing of attention away from the visceral respondent to the overt behavioral one.

An analysis of some sensitizing agents in the pathogenesis of stress-induced gastric erosive disease

Prior surgical implantation of a venous catheter sensitized rats to cold-immobilization stress. Three of six catheterized females succumbed during the stress. The remaining rats fell into two groups in terms of their core temperature at the end of the stress period: Male uncatheterized rats had higher temperatures than rats in the other three groups. No relation was found between catheter patency and magnitude of hypothermia. Degree of gastric disease paralleled the core temperature findings in that the male uncatheterized rats had significantly fewer gastric erosions than the rats in the other three groups. Additionally, a robust effect of gender was found with uncatheterized females showing more hypothermia and more gastric disease than uncatheterized males. A subsequent experiment was conducted to evaluate whether anesthesia or wearing the protective spring was responsible in part for the sensitization seen. Here, the gender difference was less although females consistently averaged lower core temperatures after stress than did males. Despite similar core temperatures after stress, females that were prepared with the protective spring apparatus developed more gastric disease than female controls or similarly treated males. Thus, the additional sensitization exhibited by females in the first experiment may relate to the fact that both catheterization and the taping procedure were sensitizers while only catheterization was a sensitizer for males.

Roles of stress and adaptation in the elicitation of face-immersion bradycardia

Thirteen young healthy human volunteers immersed their faces in warm or cold water on one day while breathing through a snorkel and on another day while breath holding. The magnitude of the elicited bradycardia was most prominently due to water temperature, with apnea playing a less important role. Perceived stress could affect the magnitude of the response, but it was less important than the other variables. Thus statistically significant nonparametric correlations were found for the group but not for most individuals between a scoring technique that assessed perceived stress and heart rate. In contrast to animals, these data indicate that bradycardia may be reliably elicited in humans by face immersion in cold water and that stress is neither necessary nor sufficient to produce this phenomenon. Adaptation did not seem to play a role in the development of this physiological response.