The Emergence of Specialized Roles Within Groups

Humans routinely form groups to achieve goals that no individual can accomplish alone. Group coordination often brings to mind synchrony and alignment, where all individuals do the same thing (e.g., driving on the right side of the road, marching in lockstep, or playing musical instruments on a regular beat). Yet, effective coordination also typically involves differentiation, where specialized roles emerge for different members (e.g., prep stations in a kitchen or positions on an athletic team). Role specialization poses a challenge for computational models of group coordination, which have largely focused on achieving synchrony. Here, we present the CARMI framework, which characterizes role specialization processes in terms of five core features that we hope will help guide future model development: Communication, Adaptation to feedback, Repulsion, Multi-level planning, and Intention modeling. Although there are many paths to role formation, we suggest that roles emerge when each agent in a group dynamically allocates their behavior toward a shared goal to complement what they expect others to do. In other words, coordination concerns beliefs (who will do what) rather than simple actions. We describe three related experimental paradigms-"Group Binary Search," "Battles of the Exes," and "Find the Unicorn"-that we have used to study differentiation processes in the lab, each emphasizing different aspects of the CARMI framework.

Mental health and academic experiences among U.S. college students during the COVID-19 pandemic

When the COVID-19 pandemic began, U.S. college students reported increased anxiety and depression. This study examines mental health among U.S college students during the subsequent 2020-2021 academic year by surveying students at the end of the fall 2020 and the spring 2021 semesters. Our data provide cross-sectional snapshots and longitudinal changes. Both surveys included the PSS, GAD-7, PHQ-8, questions about students' academic experiences and sense of belonging in online, in-person, and hybrid classes, and additional questions regarding behaviors, living circumstances, and demographics. The spring 2021 study included a larger, stratified sample of eight demographic groups, and we added scales to examine relationships between mental health and students' perceptions of their universities' COVID-19 policies. Our results show higher-than-normal frequencies of mental health struggles throughout the 2020-2021 academic year, and these were substantially higher for female college students, but by spring 2021, the levels did not vary substantially by race/ethnicity, living circumstances, vaccination status, or perceptions of university COVID-19 policies. Mental health struggles inversely correlated with scales of academic and non-academic experiences, but the struggles positively correlated with time on social media. In both semesters, students reported more positive experiences with in-person classes, though all class types were rated higher in the spring semester, indicating improvements in college students' course experiences as the pandemic continued. Furthermore, our longitudinal data indicate the persistence of mental health struggles across semesters. Overall, these studies show factors that contributed to mental health challenges among college students as the pandemic continued.

Nitrogen processing by treatment wetlands in a tropical catchment dominated by agricultural landuse

Agriculture is a major contributor to marine nitrogen pollution, and treatment wetlands can be a strategy to reduce it. However, few studies have assessed the potential of treatment wetlands to mitigate nitrogen pollution in tropical regions. We quantify the nitrogen removal rates of four recently constructed treatment wetlands in tropical Australia. We measured denitrification potential (D_t), the inflow-outflow of nutrients, and tested whether the environment in these tropical catchments is favourable for nitrogen removal. D_t was detected in three of the four systems with rates between 2.0 and 12.0 mg m^-2 h^-1; the highest rates were measured in anoxic soils (ORP -100 to 300 mV) that were rich in carbon and nitrogen (>2% and >0.2%, respectively). The highest nitrogen removal rates were measured when NO₃^--N concentrations were >0.4 mg L^-1 and when water flows were slow. Treatment wetlands in tropical regions can deliver high removal rates of nitrogen and other pollutants when adequately managed. This strategy can reduce nutrient loads and their impacts on sensitive coastal zones such as the Great Barrier Reef.

Trend differences in men and women in rural and urban U.S. settings

BACKGROUND

Smoking prevalence is declining at a slower rate in rural than urban settings in the United States (U.S.), and known predictors of smoking do not readily account for this trend difference. Given that socioeconomic and psychosocial determinants of health disparities accumulate in rural settings and that life-course disadvantages are often greater in women than men, we examined whether smoking trends are different for rural and urban men and women.

METHOD

We used yearly cross-sectional data (n = 303,311) from the U.S. National Survey on Drug Use and Health (NSDUH) from 2007 through 2014 to compare cigarette smoking trends in men and women across rural and urban areas. Current smoking status was modelled using logistic regression controlling for confounding risk factors.

RESULTS

Regression derived graphs predicting unadjusted prevalence estimates and 95% confidence bands revealed that whereas the smoking trends of rural men, urban men, and urban women significantly declined from 2007 to 2014, the trend for rural women was flat. Controlling for demographic, socioeconomic and psychosocial predictors of smoking did not explain rural women's significantly different trend from those of the other three groups.

CONCLUSION

Rural women lag behind rural men, urban men and urban women in decreasing smoking, a health disparity finding that supports the need for tobacco control and regulatory policies and interventions that are more effective in reducing smoking among rural women.

Regional Rural-Urban Differences in E-Cigarette Use and Reasons for Use in the United States

PURPOSE

To determine whether there are rural/urban differences in e-cigarette use and reasons for use that vary across the 10 Health & Human Services (HHS) regions.

METHODS

Age-adjusted bivariate and multivariable analyses were conducted for n = 225,413 respondents to the 2014-2015 Tobacco Use Supplement-Current Population Survey to estimate the prevalence of e-cigarette use. Reasons for e-cigarette use were collected from n = 16,023 self-respondents who reported ever using e-cigarettes.

FINDINGS

While nationally rural residents appeared more likely to use e-cigarettes, adjusted results indicated that current e-cigarette use was significantly less likely across the northern and western regions (New England, East North Central, Heartland, North Central Mountain, Northwest, and Southwest Pacific regions). Reasons for e-cigarette use differed by urban/rural status and region; for example, the rationale to use e-cigarettes as a smoking cessation aid was significantly more common among rural compared to urban adults in the New England and New York/New Jersey regions, but less common in the Southeast.

CONCLUSIONS

For several regions, there were no significant rural/urban differences in e-cigarette use and reasons for use. Yet those regions that present differences face the need to develop public health approaches to minimize urban/rural disparities in health education, services, and outcomes related to tobacco use, particularly where access to health care is limited. Public health campaigns and guidance for clinical care within HHS regions should be tailored to reflect regional differences in beliefs about e-cigarettes.

A growing geographic disparity: Rural and urban cigarette smoking trends in the United States

Rural areas of the United States have a higher smoking prevalence than urban areas. However, no recent studies have rigorously examined potential changes in this disparity over time or whether the disparity can be explained by demographic or psychosocial characteristics associated with smoking. The present study used yearly cross sectional data from the National Survey on Drug Use and Health from 2007 through 2014 to examine cigarette smoking trends in rural versus urban areas of the United States. The analytic sample included 303,311 respondents. Two regression models were built to examine (a) unadjusted rural and urban trends in prevalence of current smoking and (b) whether differences remained after adjusting for demographic and psychosocial characteristics. Results of the unadjusted model showed disparate and diverging cigarette use trends during the 8-year time period. The adjusted model also showed diverging trends, initially with no or small differences that became more pronounced across the 8-year period. We conclude that differences reported in earlier studies may be explained by differences in rural versus urban demographic and psychosocial risk factors, while more recent and growing disparities appear to be related to other factors. These emergent differences may be attributable to policy-level tobacco control and regulatory factors that disproportionately benefit urban areas such as enforcement of regulations around the sale and marketing of tobacco products and treatment availability. Strong federal policies and targeted or tailored interventions may be important to expanding tobacco control and regulatory benefits to vulnerable populations including rural Americans.

Belatacept-Resistant Rejection Is Associated With CD28+ Memory CD8 T Cells

Recently, newer therapies have been designed to more specifically target rejection in an effort to improve efficacy and limit unwanted toxicity. Belatacept, a CD28-CD80/86 specific reagent, is associated with superior patient survival and graft function compared with traditional therapy, but its adoption as a mainstay immunosuppressive therapy has been tempered by increased rejection rates. It is essential that the underlying mechanisms associated with this rejection be elucidated before belatacept is more widely used. To that end, we designed a study in a nonhuman primate kidney transplant model where animals were treated with either a belatacept- or a tacrolimus-based immunosuppressive regimen. Interestingly, we found that elevated pretransplant frequencies of CD28⁺ CD8⁺ T_EMRA cells are associated with rejection on belatacept but not tacrolimus treatment. Further analysis showed that the CD28⁺ CD8⁺ T_EMRA cells rapidly lose CD28 expression after transplant in those animals that go on to reject with the allograft infiltrate being predominantly CD28^- . These data suggest that CD28⁺ memory T cells may be resistant to belatacept, capable of further differentiation including loss of CD28 expression while maintaining effector function. The unique signaling requirements of CD28⁺ memory T cells provide opportunities for the development of targeted therapies, which may synergize with belatacept to prevent costimulation-independent rejection.

Cytosolic 5'-nucleotidase 1A autoantibody profile and clinical characteristics in inclusion body myositis

OBJECTIVES

Autoantibodies directed against cytosolic 5'-nucleotidase 1A have been identified in many patients with inclusion body myositis. This retrospective study investigated the association between anticytosolic 5'-nucleotidase 1A antibody status and clinical, serological and histopathological features to explore the utility of this antibody to identify inclusion body myositis subgroups and to predict prognosis.

MATERIALS AND METHODS

Data from various European inclusion body myositis registries were pooled. Anticytosolic 5'-nucleotidase 1A status was determined by an established ELISA technique. Cases were stratified according to antibody status and comparisons made. Survival and mobility aid requirement analyses were performed using Kaplan-Meier curves and Cox proportional hazards regression.

RESULTS

Data from 311 patients were available for analysis; 102 (33%) had anticytosolic 5'-nucleotidase 1A antibodies. Antibody-positive patients had a higher adjusted mortality risk (HR 1.89, 95% CI 1.11 to 3.21, p=0.019), lower frequency of proximal upper limb weakness at disease onset (8% vs 23%, adjusted OR 0.29, 95% CI 0.12 to 0.68, p=0.005) and an increased prevalence of excess of cytochrome oxidase deficient fibres on muscle biopsy analysis (87% vs 72%, adjusted OR 2.80, 95% CI 1.17 to 6.66, p=0.020), compared with antibody-negative patients.

INTERPRETATION

Differences were observed in clinical and histopathological features between anticytosolic 5'-nucleotidase 1A antibody positive and negative patients with inclusion body myositis, and antibody-positive patients had a higher adjusted mortality risk. Stratification of inclusion body myositis by anticytosolic 5'-nucleotidase 1A antibody status may be useful, potentially highlighting a distinct inclusion body myositis subtype with a more severe phenotype.

Targeting Lyn regulates Snail family shuttling and inhibits metastasis

The acquisition of an invasive phenotype by epithelial cells occurs through a loss of cellular adhesion and polarity, heralding a multistep process that leads to metastatic dissemination. Since its characterization in 1995, epithelial-mesenchymal transition (EMT) has been closely linked to the metastatic process. As a defining aspect of EMT, loss of cell adhesion through downregulation of E-cadherin is carried out by several transcriptional repressors; key among them the SNAI family of transcription factors. Here we identify for the first time that Lyn kinase functions as a key modulator of SNAI family protein localization and stability through control of the Vav-Rac1-PAK1 (Vav-Rac1-p21-activated kinase) pathway. Accordingly, targeting Lyn in vitro reduces EMT and in vivo reduces metastasis of primary tumors. We also demonstrate the clinical relevance of targeting Lyn as a key player controlling EMT; patient samples across many cancers revealed a strong negative correlation between Lyn and E-cadherin, and high Lyn expression in metastatic tumors as well as metastasis-prone primary tumors. This work reveals a novel pancancer mechanism of Lyn-dependent control of EMT and further underscores the role of this kinase in tumor progression.

An international systematic mapping review of fieldwork education in occupational therapy

BACKGROUND

Owing to its importance in preparing occupational therapists, fieldwork education has generated numerous studies. These have not been collected and reviewed, leaving researchers without a map for growing a science of fieldwork education.

PURPOSE

This study aimed to systematically categorize the topics, research designs, methods, levels of impact, and themes that have and have not been addressed in fieldwork education scholarship.

METHOD

Guided by a systematic mapping review design, 124 articles, identified through database searches and inclusion coding, were studied. Data were collected using a data extraction instrument and analyzed using Microsoft Access queries.

FINDINGS

Papers primarily addressed curriculum (n = 51) and students (n = 32). Conceptual/descriptive inquiry methods (n = 57) were predominant. Qualitative (n = 48) and quantitative methods (n = 49) were used equally. Research outcomes mainly targeted perceived participation in fieldwork. Recurring themes included student perceptions, external influences, and transition to practice.

IMPLICATIONS

Three recommendations were identified: strengthen procedures for studying singular fieldwork experiences, broaden rationales for studying fieldwork, and translate educational concepts for occupational therapy.

Lyn activity protects mice from DSS colitis and regulates the production of IL-22 from innate lymphoid cells

Intestinal homeostasis requires a complex balance of interactions between diverse resident microbial communities, the intestinal epithelium, and the underlying immune system. We show that the Lyn tyrosine kinase, a critical regulator of immune cell function and pattern-recognition receptor (PRR) responses, has a key role in controlling gastrointestinal inflammation. Lyn⁻/⁻ mice were highly susceptible to dextran sulfate sodium (DSS)-induced colitis, whereas Lyn gain-of-function (Lyn(up)) mice exhibited attenuated colitis during acute and chronic models of disease. Lyn(up) mice were hypersensitive to lipopolysaccharide (LPS), driving enhanced production of cytokines and factors associated with intestinal barrier function, including interleukin (IL)-22. Oral administration of LPS was sufficient to protect antibiotic-treated Lyn(up) but not wild-type mice from DSS, highlighting how Lyn-dependent changes in the nature/magnitude of PRR responses can impact intestinal health. Furthermore, protection from DSS-induced colitis and increased IL-22 production in response to LPS did not depend on the adaptive immune system, with increased innate lymphoid cell-derived IL-22 correlating with Lyn activity in dendritic cells. These data reveal a key role for Lyn in the regulation of innate immune responses and control of intestinal inflammation.

Socioeconomic deprivation, readmissions, mortality and acute exacerbations of bronchiectasis

BACKGROUND

Bronchiectasis is known to cause significant morbidity in children in New Zealand. Little is known of the disease in adults.

AIM

Our objective was to characterise a cohort of adults who presented to hospital with acute exacerbations of the disease.

METHODS

We retrospectively collected information on all exacerbations treated as inpatients from a single hospital in South Auckland, New Zealand during 2002.

RESULTS

We collected information on 307 exacerbations in 152 patients. Twenty-seven per cent were of Maaori ethnic origin, and 44% Pacific. Seventy per cent lived in areas categorised as the 20% most deprived in New Zealand. Comorbid conditions were present in 80% of patients - most commonly chronic obstructive pulmonary disease, asthma, diabetes and cardiac disease. Seventy (46%) patients had at least one readmission and 32 patients (21%) died within 12 months of admission to hospital. Greater deprivation was associated with increased mortality at 12 months after admission after adjusting for other factors (OR 11, 95% CI 2.0-61, P= 0.006). In the subgroup who underwent high-resolution computed tomographic scanning (93), increasing severity of bronchiectasis (modified Bhalla score) was associated with readmission within 12 months (P= 0.004), but not mortality (P= 0.419).

CONCLUSIONS

We have shown that exacerbations of bronchiectasis in South Auckland are more common in patients who are predominantly of Maaori or Pacific descent and are socioeconomically deprived. Admission to hospital for an exacerbation is associated with high readmission and mortality rates.

CCR3 induced-p42/44 MAPK activation protects against staurosporine induced-DNA fragmentation but not apoptosis in airway smooth muscle cells

BACKGROUND

Chemokine receptors (CCRs) are expressed on airway smooth muscle (ASM) cells. As their ligands are present in the airways in asthma, we hypothesized that ASM CCR activation could promote the increase in ASM mass seen in patients with chronic asthma.

OBJECTIVE

To determine which CCRs are expressed by ASM cells and their potential functional relevance to the chronic airway changes seen in asthma.

METHODS

CCR expression in primary ASM cell cultures and airway biopsies from patients with and without asthma was examined by RT-PCR, fluorescence-activated cell sorting and immunohistochemistry. ASM p42/44 MAPK activity, proliferation, migration and apoptosis were examined by western blotting, thymidine incorporation, transwell assay and TUNEL assay respectively.

RESULTS

CCR3 was the most frequently expressed CCR protein and was present on 79 ± 14% of cells. CX3CR1 and CXCR6 were present on 6% and 11% of cells respectively. CCR3 ligands CCL11 and CCL24 caused rapid activation of p42/44 MAPK but not Akt. CCR3 activation did not affect ASM proliferation, migration or VEGF secretion. DNA fragmentation detected by TUNEL staining could be induced by staurosporine and Fas activation although only Fas activation resulted in caspase 3 cleavage. CCL11 and CCL24 protected ASM cells against DNA fragmentation dependent upon p42/44 MAPK activity only via caspase 3 independent pathways. CCR3 was expressed in the smooth muscle and epithelium in the airways of patients with and without asthma. Smooth muscle cell DNA fragmentation in the airways of patients with stable asthma and controls was very uncommon.

CONCLUSIONS AND CLINICAL RELEVANCE

CCR3 is strongly expressed by ASM cells in vitro and in vivo. Protection against cell death by CCR3 activation is dependent on p42/44 MAPK but does not affect caspase 3 mediated apoptosis.

Knowledge of resources and competitors in human foraging

The allocation of human participants to resources was studied by observing the population dynamics of people interacting in real time within a common virtual world. Resources were distributed in two spatially separated pools with varying relative reinforcement rates (50-50, 65-35, or 80-20). We manipulated whether the participants could see each other and the distribution of the resources. When the participants could see each other but not the resources, the richer pool was underutilized. When the participants could see the resources but not each other, the richer pool was overutilized. In conjunction with prior experiments that correlated the visibility of agents and resources (Goldstone & Ashpole, 2004), these results indicate that participants' foraging decisions are influenced by both forager and resource information. The results suggest that the presence of a crowd at a resource is a deterring, rather than an attractive, factor. Both fast and slow oscillations in the harvesting rates of the pools across time were revealed by Fourier analyses. The slow waves of crowd migration were most prevalent when the resources were invisible, whereas the fast cycles were most prevalent when the resources were visible and the participants were invisible.

Chronic cold acclimation increases thermogenic capacity, non-shivering thermogenesis and muscle citrate synthase activity in both wild-type and brown adipose tissue deficient mice

The purpose of this study was to determine whether chronic cold exposure would increase the aerobic capacity of skeletal muscle in UCP-dta mice, a transgenic line lacking brown adipose tissue (BAT). Wild type and UCP-dta mice were acclimated to either warm (23 °C), or cold (4 °C) conditions. Cold increased muscle oxidative capacity nearly equivalently in wild-type and UCP-dta mice, but did not affect the respiratory function of isolated mitochondria. Summit metabolism ( ̇V O2summit) and norepinephrine-induced thermogenesis ( ̇V O2NST) were significantly lower in UCP-dta mice relative to wild-type mice regardless of temperature treatment, but both were significantly higher in cold relative to warm acclimated mice. BAT mass was significantly higher in the cold relative to warm acclimated wild-type mice, but not in cold acclimated UCP-dta mice. BAT citrate synthase activity was lower in transgenic animals regardless of acclimation temperature and BAT citrate synthase activity per depot was significantly higher only in the cold acclimated wild-type mice. Muscle citrate synthase activity was increased in both genotypes. As defects in muscle oxidative function have been observed with obesity and type 2 diabetes, these results suggest that chronic cold exposure is a useful intervention to drive skeletal muscle oxidative capacity in mouse models of obesity.

Adaptive group coordination and role differentiation

Many real world situations (potluck dinners, academic departments, sports teams, corporate divisions, committees, seminar classes, etc.) involve actors adjusting their contributions in order to achieve a mutually satisfactory group goal, a win-win result. However, the majority of human group research has involved situations where groups perform poorly because task constraints promote either individual maximization behavior or diffusion of responsibility, and even successful tasks generally involve the propagation of one correct solution through a group. Here we introduce a group task that requires complementary actions among participants in order to reach a shared goal. Without communication, group members submit numbers in an attempt to collectively sum to a randomly selected target number. After receiving group feedback, members adjust their submitted numbers until the target number is reached. For all groups, performance improves with task experience, and group reactivity decreases over rounds. Our empirical results provide evidence for adaptive coordination in human groups, and as the coordination costs increase with group size, large groups adapt through spontaneous role differentiation and self-consistency among members. We suggest several agent-based models with different rules for agent reactions, and we show that the empirical results are best fit by a flexible, adaptive agent strategy in which agents decrease their reactions when the group feedback changes. The task offers a simple experimental platform for studying the general problem of group coordination while maximizing group returns, and we distinguish the task from several games in behavioral game theory.

Discoidin domain receptor 1 regulates bronchial epithelial repair and matrix metalloproteinase production

Discoidin domain receptor (DDR)1 is an extracellular matrix (ECM)-sensing receptor tyrosine kinase, which is activated by collagen and expressed in bronchial epithelium. DDR1 is responsible for maintaining the normal structure of skin and kidney epithelia and we hypothesised that DDR1 plays a regulatory role in bronchial epithelial integrity by transducing signals from the airway ECM. Effects of DDR1 depletion were studied using RNA interference in primary human bronchial epithelial cells (HBECs) and BEAS-2B cells. The effects of overexpression of DDR1a and DDR1b in BEAS-2B cells were studied using a plasmid vector. We measured the effects on epithelial repair using a scratch wounding model, and levels of matrix metalloproteinases (MMPs) by gelatin zymography (MMP-2 and -9) and ELISA (MMP-7). We showed that knockdown of DDR1 slowed epithelial repair by 50%, which was associated with a reduction in levels of MMP-7, whilst DDR1 overexpression enhanced epithelial repair. DDR1 knockdown reduced proliferation of HBECs, but had no significant effect on adhesion to collagen I or other matrix substrates. These data suggest that ECM signalling via DDR1 regulates aspects of bronchial epithelial repair, integrity and MMP expression in the airways.

Emergent Processes in Group Behavior

Just as neurons interconnect in networks that create structured thoughts beyond the ken of any individual neuron, so people spontaneously organize themselves into groups to create emergent organizations that no individual may intend, comprehend, or even perceive. Recent technological advances have provided us with unprecedented opportunities for conducting controlled laboratory experiments on human collective behavior. We describe two experimental paradigms in which we attempt to build predictive bridges between the beliefs, goals, and cognitive capacities of individuals and patterns of behavior at the group level, showing how the members of a group dynamically allocate themselves to resources and how innovations diffuse through a social network. Agent-based computational models have provided useful explanatory and predictive accounts. Together, the models and experiments point to tradeoffs between exploration and exploitation—that is, compromises between individuals using their own innovations and using innovations obtained from their peers—and the emergence of group-level organizations such as population waves, bandwagon effects, and spontaneous specialization.

Withdrawal of somatostatin analogue therapy in patients with acromegaly is associated with an increased risk of acute biliary problems

BACKGROUND

The prevalence of gallstones (GS) is increased in acromegaly and further increased by somatostatin analogue (SA) therapy. The incidence is reported at 10-63%, but they are often asymptomatic and rarely require definitive management. Evidence suggests discontinuation of SA may precipitate acute biliary problems.

OBJECTIVE

To determine the frequency of symptomatic gallstones in patients treated with SA.

DESIGN

Retrospective analysis of prospectively followed patients in our centre.

RESULTS

Fifty patients (30 male, mean age 54 +/- 16 years) were on treatment with SA on 1 January 2003. Fifteen (11 male, mean age 50 +/- 17 years) have since discontinued SA with three proceeding to develop acute cholecystitis and two, biliary colic necessitating cholecystectomy. Three of the five had abnormal liver enzymes at or within 3 months of symptomatic presentation. Two of the remaining 35 patients experienced biliary colic necessitating cholecystectomy. These data indicate a highly significant increase in acute biliary problems on discontinuing SA (5 in 27.67 patient 'off-treatment' years vs. 2 in 299 patient treatment years, chi(2), P < 0.0001). All seven patients experiencing problems were male (P = 0.01).

CONCLUSION

This analysis demonstrates the high incidence of symptomatic GS following SA withdrawal, particularly in men. Although liver enzymes were raised no common abnormality was evident to aid as a predictor of future symptoms. We recommend all patients due to stop SA be forewarned of the risk of acute biliary problems. Further work is required to confirm if there is a gender-related difference in the incidence of acute biliary problems on discontinuing SA therapy.

Reductions of circulating matrix metalloproteinase 2 and vascular endothelial growth factor levels after treatment with pegvisomant in subjects with acromegaly

BACKGROUND

Vascular endothelial growth factor (VEGF) is involved in activation of the matrix metalloproteinase (MMP) system; the latter is implicated in atherosclerosis and cardiovascular disease. Patients with acromegaly have reduced life expectancy primarily due to cardiac disease.

AIM

This study assessed plasma MMPs and VEGF levels in patients with active acromegaly (IGF-I > 130% upper limit of normal), and on treatment with pegvisomant.

SUBJECTS AND METHODS

Twenty patients [nine female, mean age 56.1 +/- 13.8 yr (mean +/- sd)] were studied at baseline and on pegvisomant therapy and compared with data from 25 healthy volunteers (12 female; 56.6 +/- 14.2 yr). Plasma MMP-2, MMP-9, and VEGF levels were measured.

RESULTS

Serum IGF-I fell from a baseline (mean +/- sd) level of 620.1 +/- 209.3 ng/ml to 237.5 +/- 118.5 ng/ml on pegvisomant (doses 10-60 mg; P < 0.001). MMP-2 levels at baseline were significantly higher in patients compared with healthy controls (380.7 +/- 204.8 vs. 207.4 +/- 62.6 ng/ml; P < 0.001), but with treatment a significant reduction in MMP-2 [380.7 +/- 204.8 vs. 203.0 +/- 77.4 ng/ml; P < 0.001] and VEGF (283.4 +/- 233.6 vs. 229.1 +/- 157.4 pg/ml; P = 0.008) was noted. There was no significant difference in MMP-9 levels between patients and controls at baseline (797.5 +/- 142.1 vs. 788.3 +/- 218.0 ng/ml; P = 0.87) or between baseline and posttreatment levels (797.5 +/- 142.1 vs. 780.0 +/- 214 ng/ml; P = 0.76).

CONCLUSIONS

Our novel data demonstrate that treatment of acromegaly with pegvisomant leads to reductions in MMP-2 and VEGF concentrations. Further studies are required to determine the significance of these findings with relation to cardiac disease.

Insulin sensitivity and glucose tolerance improve in patients with acromegaly converted from depot octreotide to pegvisomant

AIM AND METHOD

Insulin resistance leading, in some cases, to glucose intolerance is an important contributory factor to the cardiovascular morbidity and mortality associated with acromegaly. The aim of this study was to document changes in insulin sensitivity (IS) in a group of seven patients with acromegaly (three male, four female, mean+/-s.d. age 59+/-13 Years) treated initially with a stable dose of depot octreotide (OT; median dose 30 mg four times weekly, range 10-30 mg) for a median of 18 Months (range 16-19 Months) and who were then transferred to treatment with pegvisomant (median dose 15 mg daily, range 10-20 mg) for a median of 8 Months (range 7-9 Months). IS was assessed by homeostatic model assessment (HOMA) using fasting glucose and insulin concentrations and by a short insulin tolerance test (sITT). Body composition was assessed by dual energy X-ray absorptiometry.

RESULTS

Mean+/-s.d. serum IGF-I concentrations during therapy with OT and with pegvisomant were not statistically different (283+/-119 ng/ml on OT vs 191+/-39 ng/ml on pegvisomant (P=0.4)). However, mean+/-s.d. fasting plasma glucose fell from 6.2+/-1.0 mmol/l on OT to 5.2+/-0.6 mmol/l on pegvisomant (P=0.017) and was lower on pegvisomant in all seven patients. In four patients, fasting plasma glucose fell from values diagnostic of diabetes mellitus or impaired fasting glucose on OT to within the normal range on pegvisomant. Mean+/-s.d. peripheral IS (by sITT) increased from 139+/-39 micromol/l per min on OT to 169+/-59 micromol/l per min on pegvisomant (P=0.037). Mean+/-s.d. IS (by HOMA %S) was unchanged over the course of the study (149.1+/-43.7% on OT vs 139.9+/-76.6% on pegvisomant, P=0.28). Mean+/-s.d. pancreatic beta-cell secretory function (HOMA %B) improved significantly on pegvisomant compared with OT (49.4+/-19.2% vs 82.4+/-43.5%, P=0.01). No statistically significant change in total fat (P=0.3), % fat (P=0.28) or circulating non-esterified fatty acids (P=0.35) was observed.

CONCLUSIONS

IS and glucose tolerance improved in patients converted from OT therapy to pegvisomant, without a change in body composition and even when serum IGF-I concentrations remained equally well controlled. This may be an important factor in the choice of medical therapy for patients with acromegaly.

A comparison of the effects of pegvisomant and octreotide on glucose, insulin, gastrin, cholecystokinin, and pancreatic polypeptide responses to oral glucose and a standard mixed meal

Standard medical therapy for patients with acromegaly includes somatostatin analogs. Owing to the widespread expression of somatostatin receptors, these may be associated with unwanted effects, such as altered glucose tolerance and impaired gut hormone release. Pegvisomant is a novel pegylated GH analog that competes with wild-type GH for GH-receptor binding sites but contains a position 120, amino acid substitution that prevents functional GH receptor dimerization, a known prerequisite for GH signal transduction and generation of IGF-I. We have studied the short-term effects of these two therapies (pegvisomant 20 mg/d for 7 d and octreotide 50 microg thrice daily for 7 d) on glucose tolerance and stimulated gut hormone release in six healthy male volunteers in an open-label, random-order, cross-over study. Subjects were assessed at baseline (oral glucose tolerance test and standard mixed meal) and on d 6 and 7 of each therapy with a minimum washout of 2 wk between treatments. Area under the curve and peak responses were analyzed using one-way repeated-measures ANOVA (on ranks where appropriate). Pegvisomant had no effect on glucose tolerance or stimulated gut hormone response during an oral glucose tolerance test and a standard meal. In contrast, octreotide significantly increased fasting plasma glucose, lowered fasting plasma insulin, and led to deterioration in glucose tolerance; three subjects developed impaired glucose tolerance and one diabetes mellitus by World Health Organization criteria. Octreotide significantly impaired stimulated release of cholecystokinin, gastrin, insulin, and pancreatic polypeptide. In conclusion, pegvisomant, unlike octreotide, is not associated with deterioration in glucose tolerance and impairment of stimulated gut hormone release in normal males.

Orthopedic footwear. Custom-made and commercially manufactured footwear

Shoes and footwear have been a part of human lives for centuries. Many take good foot health for granted. For those individuals, the commercial shoe store has hundreds of varieties of shoes in every price range. For individuals with compromised, at-risk feet, the options are reduced greatly. The foot health industry today has made available many viable options to meet specific needs. Footwear can augment successfully the treatment of foot and ankle pathology and when properly applied improve the health and lifestyle of patients.

Efficacy of once-daily tobramycin monotherapy for acute pulmonary exacerbations of cystic fibrosis: a preliminary study

Our objective was to compare the efficacy, safety, and microbiology of once-daily intravenous (IV) tobramycin with conventional 8-hourly tobramycin/ceftazidime IV therapy for acute Pseudomonas aeruginosa (PA) pulmonary exacerbations in cystic fibrosis (CF). CF patients with PA-induced pulmonary exacerbations were allocated to receive either once-daily tobramycin (Mono) or conventional therapy with tobramycin/ceftazidime given 8-hourly (Conv). The two longitudinal groups received therapy in a double-blind, randomized manner over a period of 2 years. Tobramycin doses were adjusted to achieve a daily area under the time-concentration curve of 100 mg x hr/L in both groups. Results were assessed for both short-term changes (efficacy and safety after 10 days of IV antibiotics during acute exacerbations) and long-term changes (efficacy, safety, and sputum microbiology between study entry and exit). Pulmonary function tests (PFTs) on admission were similar in both groups. After 10 days of IV antibiotics, absolute mean improvements in percent of predicted PFTs were 12.8, 12.1, and 13.7 for forced expiratory volume in 1 sec (FEV(1)), forced vital capacity (FVC), and forced expired flow between 25--75% of FVC (FEF(25--75%)) in the Conv group (n = 51 admissions) compared to 10.6, 9.9, and 10.6 in the Mono group (n = 47)(P<0.05 for all). Sixteen percent in the Conv group and 15% of patients in the Mono group did not respond to therapy by day 10. Long-term PFT patterns were similar for the Conv and Mono groups. The time between admissions did not differ. The Mono group showed a significant increase in tobramycin minimum inhibitory concentrations (MICs) against PA from study entry to study exit (P = 0.02, n = 27 strains); this failed to reach significance in the Conv group (P = 0.08, n = 25). There was no significant increase in the number of isolates, with MIC> or =8 mg/L in both groups. No short- or long-term changes in audiology or serum creatinine were found in either group. After 10 days of IV therapy, the urinary enzyme N-acetyl-beta-d-glucosaminidase/creatinine ratios increased in both groups (P0.05). This increase was greater in the Conv compared to the Mono group (P < 0.05). We conclude that this pilot study indicates once-daily tobramycin therapy to be as effective and safe as conventional 8-hourly tobramycin/ceftazidime therapy. Combination antibacterial therapy appears to offer no clinical advantage over once-daily tobramycin monotherapy. Tobramycin once-daily monotherapy is a potential alternative to conventional IV antibacterial therapy which deserves further investigation, including the impact on susceptibility of PA to tobramycin.

Efficiency of spermatogenesis: a comparative approach

Efficiency of spermatogenesis is the estimated number of spermatozoa produced per day per gram of testicular parenchyma. Spermatogenesis is the process of cell division and cell differentiation by which spermatozoa are produced in testes. Efficiency of spermatogenesis is influenced by species differences in the numerical density of germ cell nuclei and in the life span of these cells. Activities of spermatogonia, spermatocytes, and spermatids partition spermatogenesis into three major divisions (spermatocytogenesis, meiosis, and spermiogenesis, respectively). Spermatocytogenesis involves mitotic germ cell division to produce stem cells and primary spermatocytes. Meiosis involves duplication of chromosomes, exchange of genetic material, and two cell divisions that reduce the chromosome number and yield four spermatids. In spermiogenesis, spherical spermatids differentiate into mature spermatids which are released in the lumen of seminiferous tubules as spermatozoa. Spermatogenesis and germ cell degeneration can be quantified from numbers of germ cells in various developmental steps throughout spermatogenesis. Germ cell degeneration occurs throughout spermatogenesis; however, the greatest impact occurs during spermatocytogenesis and meiosis. There are species and seasonal influences on the developmental steps in spermatogenesis at which germ cell degeneration occurs. Number of Sertoli cells, amount of smooth endoplasmic reticulum of Leydig cells, and the number of missing generations of germ cells within the spermatogenic stage of the cycle influence efficiency of spermatogenesis. Efficiency of spermatogenesis is influenced to the amount of germ cell degeneration, pubertal development, season of the year, and aging of humans and animals.

Metamorphosis of tangential visual system neurons in Drosophila

To learn about construction of the adult nervous system, we studied the differentiation of imaginal neurons in the Drosophila visual system. OL2-A and OL3 are tangential neurons that display dFMRFa neuropeptide gene expression in adults but not in larvae. The two large OL2-A neurons are generated near the end of the embryonic period and already show morphological differentiation at the start of metamorphosis. The numerous small OL3 neurons are generated postembryonically and first detected later in metamorphosis. The onset of dFMRFa transcription coincides with that of neuropeptide accumulation in OL2-A neurons, but it precedes peptide accumulation in the OL3 neurons by days. Altering each of the five conserved sequences within the minimal 256-bp OL dFMRFa enhancer affected in vivo OL transcriptional activity in two cases: alteration of a TAAT element greatly diminished and alteration of a 9-bp tandem repeat completely abolished OL2-A/OL3 reporter activity. A 46-bp concatamer containing the TAAT element, tested separately, was not active in OL neurons. We propose a model of neuronal differentiation at metamorphosis that features developmental differences between classes of imaginal neurons.

The inhibitory effect of intracerebroventricularly injected interleukin 1beta on testosterone secretion in the rat: role of steroidogenic acute regulatory protein

Exposure to disease or injury often results in impaired reproductive activity accompanied by decreased testosterone levels. After immune activation, the cytokine interleukin 1-beta (IL-1beta) circulates in high concentrations, and its exogenous administration evokes many of the sequelae of immune activation. Previously, we have shown that the administration of this cytokine into the cerebral ventricles blunts hCG-stimulated testosterone secretion. This effect, though time-dependent, occurs before significant elevation of interleukin 6 in the peripheral bloodstream, does not depend on adrenal activation, and/or changes in LH concentrations, leading us to hypothesize a direct connection between the brain and testis. To explore this mechanism further, we isolated testicular tissue from rats treated intracerebroventricularly (icv) with vehicle or IL-1beta 30 or 90 min before they were killed. We found that in vivo cytokine treatment blunted ex vivo testosterone secretion in response to hCG, showing that the mechanism is independent of circulating cytokines. Though hCG binding was moderately reduced by icv IL-1beta in these preparations, the extent of this inhibition did not explain our observations. As the first acutely and hormonally regulated step in the biosynthesis of testosterone is the transfer of cholesterol into the inner mitochondrial membrane, which is mediated by steroidogenic acute regulatory (StAR) protein, we hypothesized that the rapid effects of icv IL-1beta on testicular responsiveness to hCG might be due to reduced levels of StAR. We report here that StAR protein was indeed reduced in Leydig cells isolated from rats treated in vivo with IL-1beta. Furthermore, treatment with a water-permeable form of cholesterol that bypasses the requirement for StAR partially restored hCG-stimulated testosterone secretion from testes isolated from rats treated icv with IL-1beta. Taken together, our data indicate that StAR plays a role in the suppression of testicular function evoked by central administration of IL-1beta.

Reflex decreases in intragastric pressure in response to cholecystokinin in rats

The actions of intravenous sulfated cholecystokinin octapeptide (CCK-8) on intraluminal pressure in the body of the stomach were studied in urethan-anesthetized rats. There was a dose-related decrease in pressure in response to CCK-8 over the range 0.3-33 pmol. Bilateral cervical vagotomy alone reduced the response to CCK-8 and together with splanchnic section abolished it. Hexamethonium also reduced the response. Vagotomy did not change the response to CCK-8 in hexamethonium-treated rats, but celiac ganglionectomy abolished it. Guanethidine and phentolamine, but not propranolol, significantly decreased the response to CCK-8; subsequent vagotomy abolished the response. Similarly, depletion of tissue catecholamines by pretreatment with 6-OH dopamine, reserpine, or celiac ganglionectomy together with vagal section abolished the effect of CCK-8. It concluded that CCK-8 decreases mean intragastric pressure in the rat by pathways involving both vagal and splanchnic nerves. The splanchnic pathway involves an alpha-adrenergic mechanism but is hexamethonium resistant. The vagal pathway is hexamethonium sensitive and nonadrenergic. Similar pathways may mediate the effect of CCK on gastric emptying.

The therapeutic value in the autopsy request

Recently the number of autopsies performed in the United States has declined. Although the benefits of the autopsy for physicians are many, we maintain, based on our own experiences, that it helps them accept the reality of loss of a loved one and enables them to begin the process of "letting go". Realization of the therapeutic value of the autopsy request should enable those who work with the recently bereaved, such as physicians and clergy, to fulfill more effective roles.

Auditory and vestibular damage in head injuries at work

A series of 50 unselected patients who reported a head injury to the Workers' Compensation Board of British Columbia were referred to the AudioVestibular Unit of the Vancouver General Hospital for studies of auditory and vestibular function. All patients were interviewed and examined by a neuro-otology team during the course of their investigation. It was found that dizziness was the most common symptom of which they complained (60%), and bleeding from the ear was the least common (4%). Of the 50 patients studied, 32% showed evidence of either auditory and/or vestibular injury. Of the total number studied, 16% had auditory injuries and 26% had vestibular injuries. The most common auditory injury was unilateral partial loss of hearing. Central vestibular dysfunction was the most common vestibular injury. A study of the most effective means of selecting patients from the population with head injuries for referral for audiology and vestibular testing was undertaken. The most effective combination of symptoms for referral is the presence of one or more of the triad: hearing loss, unsteadiness, or loss of consciousness/amnesia.

Comparative study of pure-tone, impedance, and otoscopic hearing screening methods. A survey of native Indian children in British Columbia

A survey of 1,109 native Indian children in five communities in British Columbia was conducted to determine incidence of middle ear pathologic features and to compare impedance and pure-tone audiometry as hearing screening methods. Survey teams included a public health nurse, two otologists, and two audiologists. On ear, nose, and throat (ENT) otoscopic examination, the incidence of middle ear disease requiring treatment was 12%. Disease was most prevalent in the preschool- and primary school-aged children. Pure-tone audiometry yielded 62% normal and 19% abnormal results. Nineteen percent of the children could not be tested by this method. Impedance audiometry yielded 54% normal and 38% abnormal results on the stringent criteria used to define the parameters of normality. Eight percent of the children could not be tested. Since there was a high incidence of middle ear pathologic features in the preschool group of children who could not be successfully evaluated by pure-tone audiometry, it is suggested that further investigation of impedance audiometry be undertaken in order to define parameters that will provide the most reliable referral criteria.

Psoriatic arthritis. Follow-up study

227 patients with psoriasis and various forms of arthritis have been kept under review. Psoriasis and inflammatory arthropathy was present in 168 patients, of whom 94 have been followed up for more than 10 years. An arthritis indistinguishable from rheumatoid disease was present in 78%, distal joint arthritis in 16-6%, and deforming arthritis in 4-8%. There was a female predominance in the sex ratio of patients, although males predominated in the distal joint group (male:female 1-5:1). The peak age of onset was between 36 and 45 years, although in the deforming group the arthritis began before the age of 20 three times as commonly as it did in the indistinguishable group. Onset was acute in nearly half of the patients. At onset the distal joints were affected in one-third of the distal joint group. A synchronous onset of skin and joint changes was uncommon. Skin lesions usually preceded the arthritis but occurred after onset in 16%. Apart from in the deforming group, the arthritis was mild, judged by the number of admissions to hospital for treatment of the joint disease, and the time off work. Deterioration clinically and radiographically occurred in only a small portion of the distal joint and indistinguishable groups. Antimalarial drugs have been used in 7 patients, with deterioration of the skin condition in 4. Uveitis occurred particularly in the men of all three groups, but was most frequent in those with deforming arthritis. A family history of psoriasis was obtained in 26% of first-degree relatives and 13% of second-degree relatives. A history of polyarthritis was most common in patients in the deforming group. The sheep cell agglutination test was negative in the majority, but was positive in 16% of the indistinguishable group, fluctuating in a further 10%. A small number of joints only deteriorated radiographically (10% of the distal and indistinguishable groups). The men in the distal group showed greater radiographic changes and more deterioration in the terminal interphalangeal joints of the fingers than the women. Similarly they showed more deterioration of the metatarsophalangeal joints than the women. 18 patients died, one with gastric haemorrhage resulting from treatment of exfoliative psoriasis with immunosuppressive therapy, and 2 from bronchopneumonia thought to be related to immobility caused by the arthritis.