Reduced lateralization of multiple functional brain networks in autistic males

BACKGROUND

Autism spectrum disorder has been linked to a variety of organizational and developmental deviations in the brain. One such organizational difference involves hemispheric lateralization, which may be localized to language-relevant regions of the brain or distributed more broadly.

METHODS

In the present study, we estimated brain hemispheric lateralization in autism based on each participant's unique functional neuroanatomy rather than relying on group-averaged data. Additionally, we explored potential relationships between the lateralization of the language network and behavioral phenotypes including verbal ability, language delay, and autism symptom severity. We hypothesized that differences in hemispheric asymmetries in autism would be limited to the language network, with the alternative hypothesis of pervasive differences in lateralization. We tested this and other hypotheses by employing a cross-sectional dataset of 118 individuals (48 autistic, 70 neurotypical). Using resting-state fMRI, we generated individual network parcellations and estimated network asymmetries using a surface area-based approach. A series of multiple regressions were then used to compare network asymmetries for eight significantly lateralized networks between groups.

RESULTS

We found significant group differences in lateralization for the left-lateralized Language (d = -0.89), right-lateralized Salience/Ventral Attention-A (d = 0.55), and right-lateralized Control-B (d = 0.51) networks, with the direction of these group differences indicating less asymmetry in autistic males. These differences were robust across different datasets from the same participants. Furthermore, we found that language delay stratified language lateralization, with the greatest group differences in language lateralization occurring between autistic males with language delay and neurotypical individuals.

CONCLUSIONS

These findings evidence a complex pattern of functional lateralization differences in autism, extending beyond the Language network to the Salience/Ventral Attention-A and Control-B networks, yet not encompassing all networks, indicating a selective divergence rather than a pervasive one. Moreover, we observed an association between Language network lateralization and language delay in autistic males.

One leg testing in hip and knee osteoarthritis: A comparison with a two-leg oriented functional outcome measure and self-reported functional measures

OBJECTIVE

To compare the responsiveness of two unilateral lower-limb performance-based tests, the one-leg rise test and the maximal step-up test, with the bilateral 30-second chair-stand test and the self-reported measure of physical function (HOOS/KOOS). Specific aims were to evaluate responsiveness, floor/ceiling effect and association between the instruments.

METHOD

Data was included from 111 participants, mean age 61.3 years (8.3), with clinically verified hip or knee osteoarthritis, who reported less than 150 minutes/week of moderate or vigorous intensity physical activity. Responsiveness, how well the instruments captured improvements, was measured as Cohen's standardised mean difference for effect size, and was assessed from baseline to 12 months following a physical activity intervention. Other assessments were floor and ceiling effects, and correlations between tests.

RESULTS

The maximal step-up test had an effect size of 0.57 (95% CI 0.37, 0.77), the 30-second chair-stand 0.48 (95% CI 0.29, 0.68) and the one-leg rise test 0.12 (95% CI 0.60, 0.31). The one-leg rise test had a floor effect as 72% of the participants scored zero at baseline and 63% at 12 months. The correlation between performance-based tests and questionnaires was considered to be minor (r = 0.188 to 0.226) (p = 0.018 to 0.048).

CONCLUSION

The unilateral maximal step-up test seems more responsive to change in physical function compared to the bilateral 30-second chair-stand test, although the tests did not differ statistically in effect size. The maximal step-up test provides specific information about each leg for the individual and allows for comparison between the legs.

Parsing Brain Network Specialization: A Replication and Expansion of Wang et al. (2014)

One organizing principle of the human brain is hemispheric specialization, or the dominance of a specific function or cognitive process in one hemisphere or the other. Previously, Wang et al. (2014) identified networks putatively associated with language and attention as being specialized to the left and right hemispheres, respectively; and a dual-specialization of the executive control network. However, it remains unknown which networks are specialized when specialization is examined within individuals using a higher resolution parcellation, as well as which connections are contributing the most to a given network's specialization. In the present study, we estimated network specialization across three datasets using the autonomy index and a novel method of deconstructing network specialization. After examining the reliability of these methods as implemented on an individual level, we addressed two hypotheses. First, we hypothesized that the most specialized networks would include those associated with language, visuospatial attention, and executive control. Second, we hypothesized that within-network contributions to specialization would follow a within-between network gradient or a specialization gradient. We found that the majority of networks exhibited greater within-hemisphere connectivity than between-hemisphere connectivity. Among the most specialized networks were networks associated with language, attention, and executive control. Additionally, we found that the greatest network contributions were within-network, followed by those from specialized networks.

Reduced Lateralization of Multiple Functional Brain Networks in Autistic Males

Background

Autism spectrum disorder has been linked to a variety of organizational and developmental deviations in the brain. One such organizational difference involves hemispheric lateralization, which may be localized to language-relevant regions of the brain or distributed more broadly.

Methods

In the present study, we estimated brain hemispheric lateralization in autism based on each participant's unique functional neuroanatomy rather than relying on group-averaged data. Additionally, we explored potential relationships between the lateralization of the language network and behavioral phenotypes including verbal ability, language delay, and autism symptom severity. We hypothesized that differences in hemispheric asymmetries in autism would be limited to the language network, with the alternative hypothesis of pervasive differences in lateralization. We tested this and other hypotheses by employing a cross-sectional dataset of 118 individuals (48 autistic, 70 neurotypical). Using resting-state fMRI, we generated individual network parcellations and estimated network asymmetries using a surface area-based approach. A series of multiple regressions were then used to compare network asymmetries for eight significantly lateralized networks between groups.

Results

We found significant group differences in lateralization for the left-lateralized Language (d = -0.89), right-lateralized Salience/Ventral Attention-A (d = 0.55), and right-lateralized Control-B (d = 0.51) networks, with the direction of these group differences indicating less asymmetry in autistic individuals. These differences were robust across different datasets from the same participants. Furthermore, we found that language delay stratified language lateralization, with the greatest group differences in language lateralization occurring between autistic individuals with language delay and neurotypical individuals.

Limitations

The generalizability of our findings is restricted due to the male-only sample and greater representation of individuals with high verbal and cognitive performance.

Conclusions

These findings evidence a complex pattern of functional lateralization differences in autism, extending beyond the Language network to the Salience/Ventral Attention-A and Control-B networks, yet not encompassing all networks, indicating a selective divergence rather than a pervasive one. Furthermore, a differential relationship was identified between Language network lateralization and specific symptom profiles (namely, language delay) of autism.

Evidence for a Compensatory Relationship between Left- and Right-Lateralized Brain Networks

The two hemispheres of the human brain are functionally asymmetric. At the network level, the language network exhibits left-hemisphere lateralization. While this asymmetry is widely replicated, the extent to which other functional networks demonstrate lateralization remains a subject of Investigation. Additionally, it is unknown how the lateralization of one functional network may affect the lateralization of other networks within individuals. We quantified lateralization for each of 17 networks by computing the relative surface area on the left and right cerebral hemispheres. After examining the ecological, convergent, and external validity and test-retest reliability of this surface area-based measure of lateralization, we addressed two hypotheses across multiple datasets (Human Connectome Project = 553, Human Connectome Project-Development = 343, Natural Scenes Dataset = 8). First, we hypothesized that networks associated with language, visuospatial attention, and executive control would show the greatest lateralization. Second, we hypothesized that relationships between lateralized networks would follow a dependent relationship such that greater left-lateralization of a network would be associated with greater right-lateralization of a different network within individuals, and that this pattern would be systematic across individuals. A language network was among the three networks identified as being significantly left-lateralized, and attention and executive control networks were among the five networks identified as being significantly right-lateralized. Next, correlation matrices, an exploratory factor analysis, and confirmatory factor analyses were used to test the second hypothesis and examine the organization of lateralized networks. We found general support for a dependent relationship between highly left- and right-lateralized networks, meaning that across subjects, greater left lateralization of a given network (such as a language network) was linked to greater right lateralization of another network (such as a ventral attention/salience network) and vice versa. These results further our understanding of brain organization at the macro-scale network level in individuals, carrying specific relevance for neurodevelopmental conditions characterized by disruptions in lateralization such as autism and schizophrenia.

Endergonic Hydrogenation at Ambient Conditions Using an Electrochemical Membrane Reactor

Here, we determine how the hydrogen loading (x) of an electrochemical palladium membrane reactor (ePMR) varies with electrochemical conditions (e.g., applied current density, electrolyte concentration). We detail how x influences the thermodynamic driving force of an ePMR. These studies are accomplished by measuring the fugacity (P) of hydrogen desorbing from the palladium-hydrogen membrane and subsequently relating P to pressure-composition isotherms to determine x. We find that x increases with both applied current density and electrolyte concentration, but plateaus at a loading of x ≅ 0.92 in 1.0 M H₂SO₄ at -200 mA·cm^-2. The validity of the fugacity measurements is supported experimentally and computationally by: (a) electrochemical hydrogen permeation studies; and (b) a palladium-hydrogen porous flow finite element analysis (FEA) model. Both (a) and (b) agree with the fugacity measurements on the following x-dependent properties of the palladium-hydrogen system during electrolysis: (i) the onset for spontaneous hydrogen desorption; (ii) the point of steady-state hydrogen loading; and (iii) the function describing hydrogen desorption between (i) and (ii). We proceed to detail how x defines the free energy of palladium-hydrogen alloy formation (ΔG(x)_PdH), which is a descriptor for the thermodynamic driving force of hydrogenation at the PdH_x surface of an ePMR. A maximum value ΔG_PdH of 11 kJ·mol^-1 is observed, suggesting that an ePMR is capable of driving endergonic hydrogenation reactions. We empirically demonstrate this capability by reducing carbon dioxide to formate (ΔG_CO2/HCO2H = 3.4 kJ·mol^-1) at ambient conditions and neutral pH.

No difference in extra-axial cerebrospinal fluid volumes across neurodevelopmental and psychiatric conditions in later childhood and adolescence

BACKGROUND

While autism spectrum disorder has been associated with various organizational and developmental aberrations in the brain, an increase in extra-axial cerebrospinal fluid volume has recently garnered attention. A series of studies indicate that an increased volume between the ages of 6 months and 4 years was both predictive of the autism diagnosis and symptom severity regardless of genetic risk for the condition. However, there remains a minimal understanding regarding the specificity of an increased volume of extra-axial cerebrospinal fluid to autism.

METHODS

In the present study, we explored extra-axial cerebrospinal fluid volumes in children and adolescents ages 5-21 years with various neurodevelopmental and psychiatric conditions. We hypothesized that an elevated extra-axial cerebrospinal fluid volume would be found in autism compared with typical development and the other diagnostic group. We tested this hypothesis by employing a cross-sectional dataset of 446 individuals (85 autistic, 60 typically developing, and 301 other diagnosis). An analysis of covariance was used to examine differences in extra-axial cerebrospinal fluid volumes between these groups as well as a group by age interaction in extra-axial cerebrospinal fluid volumes.

RESULTS

Inconsistent with our hypothesis, we found no group differences in extra-axial cerebrospinal fluid volume in this cohort. However, in replication of previous work, a doubling of extra-axial cerebrospinal fluid volume across adolescence was found. Further investigation into the relationship between extra-axial cerebrospinal fluid volume and cortical thickness suggested that this increase in extra-axial cerebrospinal fluid volume may be driven by a decrease in cortical thickness. Furthermore, an exploratory analysis found no relationship between extra-axial cerebrospinal fluid volume and sleep disturbances.

CONCLUSIONS

These results indicate that an increased volume of extra-axial cerebrospinal fluid may be limited to autistic individuals younger than 5 years. Additionally, extra-axial cerebrospinal fluid volume does not differ between autistic, neurotypical, and other psychiatric conditions after age 4.

Evidence for normal extra-axial cerebrospinal fluid volume in autistic males from middle childhood to adulthood

Autism spectrum disorder has long been associated with a variety of organizational and developmental abnormalities in the brain. An increase in extra-axial cerebrospinal fluid volume in autistic individuals between the ages of 6 months and 4 years has been reported in recent studies. Increased extra-axial cerebrospinal fluid volume was predictive of the diagnosis and severity of the autistic symptoms in all of them, irrespective of genetic risk for developing the disorder. In the present study, we explored the trajectory of extra-axial cerebrospinal fluid volume from childhood to adulthood in both autism and typical development. We hypothesized that an elevated extra-axial cerebrospinal fluid volume would be found in autism persisting throughout the age range studied. We tested the hypothesis by employing an accelerated, multi-cohort longitudinal data set of 189 individuals (97 autistic, 92 typically developing). Each individual had been scanned between 1 and 5 times, with scanning sessions separated by 2-3 years, for a total of 439 T1-weighted MRI scans. A linear mixed-effects model was used to compare developmental, age-related changes in extra-axial cerebrospinal fluid volume between groups. Inconsistent with our hypothesis, we found no group differences in extra-axial cerebrospinal fluid volume in this cohort of individuals 3 to 42 years of age. Our results suggest that extra-axial cerebrospinal fluid volume in autistic individuals is not increased compared with controls beyond four years of age.

POS0023 RACIAL/ETHNIC AND REGIONAL DIFFERENCES IN MULTIMORBIDITY BETWEEN PATIENTS WITH RHEUMATOID ARTHRITIS AND COMPARATORS IN A LARGE NATIONWIDE US STUDY

Background:

Patients with rheumatoid arthritis (RA) have an increased burden of multimorbidity. Racial/ethnic disparities have also been associated with an increased burden of multimorbidity.

Objectives:

We aimed to compare multimorbidity among different racial/ethnic groups and geographic regions of the US in patients with RA and comparators without RA.

Methods:

We used a large longitudinal, real-world data warehouse with de-identified administrative claims for commercial and Medicare Advantage enrollees, to identify cases of RA and matched controls. Cases were defined as patients aged ≥18 years with ≥2 diagnoses of RA in January 1, 2010 - June 30, 2019 and ≥1 prescription fill for methotrexate in the year after the first RA diagnosis. Controls were persons without RA matched 1:1 to RA cases on age, sex, census region, calendar year of index date (corresponding to the date of second diagnosis code for RA), and length of prior medical/pharmacy coverage. Race was classified as non-Hispanic White (White), non-Hispanic Black (Black), Asian, Hispanic, or other/unknown, based on self-report or derived rule sets. Multimorbidity (2 or more comorbidities) was defined using 25 chronic comorbidities from a combination of the Charlson and Elixhauser Comorbidity Indices assessed during the year prior to index date. Rheumatic comorbidities were not included. Logistic regression models were used to estimate odds ratios (OR) with 95% confidence intervals (CI).

Results:

The study included 16,363 cases with RA and 16,363 matched non-RA comparators (mean age 58.2 years, 70.7% female for both cohorts). Geographic regions were the same in both cohorts: 50% South, 26% Midwest, 13% West, and 11% Northeast. Race/ethnicity was not part of the matching criteria and varied slightly between the cohorts: among RA (non-RA) patients, 74% (74%) were White, 11% (9%) Hispanic, 10% (9%) Black, 3% (4%) Asian, and 3% (4%) other/unknown. Patients with RA had more multimorbidity than non-RA subjects (51.3% vs 44.8%). Multimorbidity comparisons across US geographic regions were similar in both cohorts, with comparable multimorbidity levels for patients in the West and Midwest and higher levels for those in the Northeast and South (Figure 1). Among the non-RA patients, 43.5% of Whites experienced multimorbidity, compared to 33.9% of Asians, 46.1% of Hispanics, and 58.4% of Blacks. These associations remained after adjustment for age, sex, and geographic region, with significantly lower multimorbidity among Asians (OR: 0.81; 95%CI: 0.67-0.99) and significantly higher multimorbidity among Hispanics (OR: 1.21; 95%CI: 1.07-1.37) and Blacks (OR: 1.74; 95%CI: 1.54-1.97), compared to Whites in the non-RA cohort. Among the RA patients, racial/ethnic differences were less pronounced; 50.6% of Whites, 42.8% of Asians, 48.8% of Hispanics, and 58.4% of Blacks experienced multimorbidity. Adjusted analyses revealed no significant differences in multimorbidity for Asians (OR: 0.88; 95%CI: 0.70-1.08) and Hispanics (OR: 1.06; 95%CI: 0.95-1.19) and a less pronounced increase in multimorbidity among Blacks (OR: 1.32; 95%CI: 1.17-1.49) compared to Whites in the RA cohort.

Conclusion:

This large nationwide study showed increased occurrence of multimorbidity in RA versus non-RA patients and in both cohorts for residents of the Northeast and South regions of the US. Racial/ethnic disparities in multimorbidity were more pronounced among patients without RA compared to RA patients. This indicates the effects of RA and race/ethnicity on multimorbidity do not aggregate. The underlying mechanisms for these associations require further investigation.

Figure 1.

Logistic regression models comparing multimorbidity levels in RA and non-RA cohorts.

Disclosure of Interests:

Hayley J. Dykhoff: None declared, Elena Myasoedova: None declared, Madeline Peterson: None declared, John M Davis III Grant/research support from: Research grant from Pfizer, Vanessa Kronzer: None declared, Caitrin Coffey: None declared, Tina Gunderson: None declared, Cynthia S. Crowson: None declared.

OP0213 SEX DIFFERENCES IN MULTIMORBIDITY BETWEEN PATIENTS WITH RHEUMATOID ARTHRITIS AND COMPARATORS IN A LARGE NATIONWIDE US STUDY

Background:

Patients with rheumatoid arthritis (RA) have an increased burden of multimorbidity. Although many comorbidities vary by sex, sex differences in multimorbidity among individuals with RA have not been examined.

Objectives:

We aimed to compare multimorbidity between women and men with RA and comparators without RA.

Methods:

We used a large longitudinal, real-world data warehouse with de-identified administrative claims for commercial and Medicare Advantage enrollees, to identify cases of RA and matched controls. Cases were defined as patients aged ≥18 years with ≥2 diagnoses of RA in January 1, 2010 - June 30, 2019 and ≥1 prescription fill for methotrexate in the year after the first RA diagnosis. Controls were persons without RA matched 1:1 to RA cases on age, sex, census region, calendar year of index date (corresponding to the date of second diagnosis code for RA), and length of prior medical/pharmacy coverage. Race was classified as non-Hispanic White (White), non-Hispanic Black (Black), Asian, Hispanic, or other/unknown, based on self-report or derived rule sets. Multimorbidity (2 or more comorbidities) was defined using 25 chronic comorbidities from a combination of the Charlson and Elixhauser Comorbidity Indices assessed during the year prior to index date. Rheumatic comorbidities were not included. Logistic regression models were used to estimate odds ratios (OR) with 95% confidence intervals (CI).

Results:

The study included 16,363 cases with RA and 16,363 matched non-RA comparators (mean age 58.2 years, 70.7% female for both cohorts). In both cohorts, women were slightly younger (mean age 57.5 vs. 59.8 years). Among RA patients, women were more racially/ethnically diverse than men, with 72% of women (78% men) being White, 12% (10%) Hispanic, 11% (7%) Black, 3% (3%) Asian, and 3% (3%) other/unknown. Racial/ethnic diversity was similar among non-RA women and men with 74% women (75% men) being White, 9% (9%) Hispanic, 10% (8%) Black, 4% (4%) Asian, and 3% (4%) other/unknown. Patients with RA had more multimorbidity than non-RA subjects (51.3% vs 44.8%). Observed rates of multimorbidity were similar in women and men with RA (51.6% vs 50.5%, p=0.18), but among non-RA patients, women had lower observed rates of multimorbidity than men (43.7% vs 47.4%, p<0.0001). However, following adjustment for age, race/ethnicity, and geographic region, multimorbidity among RA patients was greater in women versus men (OR: 1.19; 95% CI: 1.11-1.28) and similar among non-RA women and men (OR: 0.97 for females; 95% CI: 0.90-1.05). Examination of individual comorbidities showed that women with RA had more depression, hypothyroidism, diabetes mellitus, and chronic pulmonary disease compared to men with RA and women without RA.

Conclusion:

This large nationwide study showed increased occurrence of multimorbidity in women with RA compared to men with RA, while women and men without RA had similar levels of multimorbidity following adjustment for age, race/ethnicity, and geographic region. The underlying mechanisms for these sex differences require further investigation.

Disclosure of Interests:

Hayley J. Dykhoff: None declared, Elena Myasoedova: None declared, Madeline Peterson: None declared, John M Davis III Grant/research support from: Research grant from Pfizer, Vanessa Kronzer: None declared, Caitrin Coffey: None declared, Tina Gunderson: None declared, Cynthia S. Crowson: None declared

FRI0560 INCREASED RISK OF RHEUMATOID ARTHRITIS DIAGNOSIS IN STATIN USERS IN A LARGE NATIONWIDE US STUDY

Background:

Studies evaluating the effect of statin use on the risk of rheumatoid arthritis (RA) onset have shown conflicting results. Most of these studies evaluated European populations while data from the US are scarce.

Objectives:

We aimed to assess the association between statin use (and intensity) and RA occurrence using claims data from the US population.

Methods:

For this case-control study, we used the OptumLabs Data Warehouse, a large administrative database of commercially insured and Medicare Advantage beneficiaries, to identify cases of RA and matched controls. Cases were defined as patients with 2 or more diagnoses of RA in January 1, 2010 - June 30, 2019 who were ≥18 years old, filled ≥1 prescription for a conventional or biologic disease modifying anti-rheumatic drug, and had no diagnoses of RA during the prior year. Controls were persons without RA matched 1:1 to RA cases on age, sex, census region, calendar year of index date (corresponding to the date of second diagnosis code for RA), and length of prior medical/pharmacy coverage. Statin use was defined as any filled prescription for a statin medication during prior coverage (excluding any new statin prescriptions filled up to 90 days before first RA diagnosis or index date). Logistic regression models were used to estimate odds ratios (OR)with 95% confidence intervals (CI) adjusted for age, sex, race, census region, calendar year and Charlson comorbidity index (excluding RA component).

Results:

The study included 32,465 cases with RA (mean age 57.0, 72.2% female) and 32,465 matched controls (mean age 57.0, 72.2% female). There were 10,759 (33.1%) statin users among RA patients and 4,016 (12.4%) statin users among the matched controls. Statin use was associated with increased risk of RA (adjusted OR 3.34, 95%CI 3.19-3.49). All levels of statin intensity were associated with increased risk of RA (high OR: 3.60, 95% CI 3.28-3.94; medium OR: 3.20, 95% CI 3.04-3.37; low OR: 3.72, 95% CI 3.34-4.15) compared to non-users. Both former and current statin users showed an increased risk of RA (current OR: 3.04, 95% CI 2.80-3.30 and former OR: 3.37, 95% CI 3.20-3.54) compared to non-users.

Conclusion:

This large nationwide study showed increased risk of RA in statin-users vs non-users. The lack of dose dependence may suggest confounding by indication or a common genetic predisposition for cardiovascular disease and RA. The underlying mechanisms for these associations require further investigation.

Disclosure of Interests:

Madeline Peterson: None declared, Hayley J. Dykhoff: None declared, Cynthia S. Crowson Grant/research support from: Pfizer research grant, John M Davis III Grant/research support from: Research grants from Pfizer, Consultant of: Served on advisory boards for Abbvie and Sanofi-Genzyme, Lindsey Sangaralingham: None declared, Elena Myasoedova: None declared

Synthesis, characterization, and electrochemical properties of a first-row metal phthalocyanine series

A first-row metal phthalocyanine series is synthesized and the effects of axial metal-ligand substitution is investigated electrochemically and in the context of charge carriers for redox-flow batteries.

The Burden of Functional Disabilities for Middle-Aged and Older Adults in the United States

OBJECTIVES

Understanding the role of functional capacity on longevity is important as the population in the United States ages. The purpose of this study was to determine the burden of instrumental activities of daily living (IADL) and activities of daily living (ADL) disabilities for a nationally-representative sample of middle-aged and older adults in the United States.

DESIGN

Longitudinal-Panel.

SETTING

Core interviews were often performed in person or over the telephone.

PARTICIPANTS

A sub-sample of 31,055 participants aged at least 50 years from the 1998-2014 waves of the Health and Retirement Study who reported having a functional disability were included.

MEASUREMENTS

Ability to perform IADLs and ADLs were self-reported at each wave. The National Death Index was used to ascertain date of death. The number of years of life that were lost (YLLs) and years lived with a disability (YLDs) were summed for the calculation of disability-adjusted life years (DALYs). Sampling weights were used in the analyses to make the DALYs nationally-representative. The results for YLLs, YLDs, and DALYs are reported in thousands.

RESULTS

Of the participants included, 14,990 had an IADL disability and 13,136 had an ADL disability. Men and women with an IADL disability had 236,037 and 233,772 DALYs, respectively; whereas, there were 178,594 DALYs for males and 253,630 DALYs for females with an ADL disability. Collectively, there were 469,809 years of healthy life lost from IADL impairments, and 432,224 years of healthy life lost from ADL limitations.

CONCLUSIONS

These findings should be used to inform healthcare providers and guide interventions aiming to preserve the functional capacity of aging adults. Prioritizing health-related resources for mitigating the burden of functional disabilities may help aging adults increase their quality of life and life expectancy over time.

Association between HbA1c and peripheral neuropathy in a 10-year follow-up study of people with normal glucose tolerance, impaired glucose tolerance and Type 2 diabetes

AIMS

To explore the association between HbA_1c and sural nerve function in a group of people with normal glucose tolerance, impaired glucose tolerance or Type 2 diabetes.

METHODS

We conducted a 10-year follow-up study in 87 out of an original 119 participants. At study commencement (2004), 64 men and 55 women (mean age 61.1 years) with normal glucose tolerance (n=39), impaired glucose tolerance (n=29), or Type 2 diabetes (n=51) were enrolled. At the 2014 follow-up (men, n=46, women, n=41; mean age 71.1 years), 36, nine and 42 participants in the normal glucose tolerance, impaired glucose tolerance and Type 2 diabetes categories, respectively, were re-tested. Biometric data and blood samples were collected, with an electrophysiological examination performed on both occasions.

RESULTS

At follow-up, we measured the amplitude of the sural nerve in 74 of the 87 participants. The mean amplitude had decreased from 10.9 μV (2004) to 7.0 μV (2014; P<0.001). A 1% increase in HbA_1c was associated with a ~1% average decrease in the amplitude of the sural nerve, irrespective of group classification. Crude and adjusted estimates ranged from -0.84 (95% CI -1.32, -0.37) to -1.25 (95% CI -2.31, -0.18). Although the mean conduction velocity of those measured at both occasions (n=73) decreased from 47.6 m/s to 45.8 m/s (P=0.009), any association with HbA_1c level was weak. Results were robust with regard to potential confounders and missing data.

CONCLUSIONS

Our data suggest an association between sural nerve amplitude and HbA_1c  at all levels of HbA_1c . Decreased amplitude was more pronounced than was diminished conduction velocity, supporting the notion that axonal degeneration is an earlier and more prominent effect of hyperglycaemia than demyelination.

Towards Catalytic Ammonia Oxidation to Dinitrogen: A Synthetic Cycle by Using a Simple Manganese Complex

Oxidation of the nucleophilic nitride, (salen)Mn≡N (1) with stoichiometric [Ar₃ N][X] initiated a nitride coupling reaction to N₂ , a major step toward catalytic ammonia oxidation (salen=N,N'-bis(salicylidene)-ethylenediamine dianion; Ar=p-bromophenyl; X=[SbCl₆ ]^- or [B(C₆ F₅ )₄ ]^- ). N₂ production was confirmed by mass spectral analysis of the isotopomer, 1-¹⁵ N, and the gas quantified. The metal products of oxidation were the reduced Mn^III dimers, [(salen)MnCl]₂ (2) or [(salen)Mn(OEt₂ )]₂ [B(C₆ F₅ )₄ ]₂ (3) for X=[SbCl₆ ]^- or [B(C₆ F₅ )₄ ]^- , respectively. The mechanism of nitride coupling was probed to distinguish a nitridyl from a nucleophilic/electrophilic coupling sequence. During these studies, a rare mixed-valent Mn^V /Mn^III bridging nitride, [(salen)Mn^V (μ-N)Mn^III (salen)][B(C₆ F₅ )₄ ] (4), was isolated, and its oxidation-state assignment was confirmed by X-ray diffraction (XRD) studies, perpendicular and parallel-mode EPR and UV/Vis/NIR spectroscopies, as well as superconducting quantum interference device (SQUID) magnetometry. We found that 4 could subsequently be oxidized to 3. Furthermore, in view of generating a catalytic system, 2 can be re-oxidized to 1 in the presence of NH₃ and NaOCl closing a pseudo-catalytic "synthetic" cycle. Together, the reduction of 1→2 followed by oxidation of 2→1 yield a genuine synthetic cycle for NH₃ oxidation, paving the way to the development of a fully catalytic system by using abundant metal catalysis.

Low first-trimester PAPP-A in IVF (fresh and frozen-thawed) pregnancies, likely due to a biological cause

PURPOSE

The purpose of this study is to confirm a difference in the first-trimester screen maternal biochemistry and false-positive rates (FPR) between pregnancies conceived spontaneously and those conceived via assisted reproductive technologies (ART).

METHODS

Retrospective analysis of the complete population of women (17,889 pregnancies) who had undergone first-trimester screening between January 2004 and September 2009 at three private ultrasound clinics in Queensland, Australia was used in the study. The age, gestation, method of conception, ultrasound markers, biochemistry markers (PAPP-A, fβ-hCG), and type of biochemical analyzer platform (Brahms Kryptor, Immulite 2000) data was collated. Univariate analysis of variance (ANOVA), Spearman's rank nonparametric correlation analysis, and Binary Logistic Regression analysis were used to analyze data. Spontaneous pregnancies were used as controls. Results were considered significant when the p value was less than 0.05.

RESULTS

After exclusions, 16,363 singleton pregnancies, including 1543 conceived via ART, were analyzed. Results from the two biochemistry platforms, Brahms Kryptor and Immulite 2000 were significantly different (p < 0.001); thus, the data was divided for analysis purposes. PAPP-A was universally significantly lower in IVF pregnancies compared to spontaneously conceived pregnancies (p < 0.001). Using the Brahms Kryptor platform, ICSI was associated with significantly decreased PAPP-A (p < 0.046), and a significantly increased FPR (p = 0.012).

CONCLUSIONS

Consistent with previous studies IVF pregnancies had significantly lower PAPP-A levels supporting the need to appropriately adjust the combined first-trimester screening (cFTS) risk algorithm for IVF conceptions. The Brahms Kryptor and Immulite 2000 platforms are significantly different; however, the universally lower PAPP-A findings support the hypothesis that the lower PAPP-A is due to a biological cause.

Application of denitrifying wood chip bioreactors for management of residential non-point sources of nitrogen

Two important and large non-point sources of nitrogen in residential areas that adversely affect water quality are stormwater runoff and effluent from on-site treatment systems. These sources are challenging to control due to their variable flow rates and nitrogen concentrations. Denitrifying bioreactors that employ a lignocellulosic wood chip medium contained within a saturated (anoxic) zone are relatively new technology that can be implemented at the local level to manage residential non-point nitrogen sources. In these systems, wood chips serve as a microbial biofilm support and provide a constant source of organic substrate required for denitrification. Denitrifying wood chip bioreactors for stormwater management include biofilters and bioretention systems modified to include an internal water storage zone; for on-site wastewater, they include upflow packed bed reactors, permeable reactive barriers, and submerged wetlands. Laboratory studies have shown that these bioreactors can achieve nitrate removal efficiencies as high as 80-100% but could provide more fundamental insight into system design and performance. For example, the type and size of the wood chips, hydraulic loading rate, and dormant period between water applications affects the hydrolysis rate of the lignocellulosic substrate, which in turn affects the amount and bioavailability of dissolved organic carbon for denitrification. Additional field studies can provide a better understanding of the effect of varying environmental conditions such as ambient temperature, precipitation rates, household water use rates, and idle periods on nitrogen removal performance. Long-term studies are also essential for understanding operations and maintenance requirements and validating mathematical models that integrate the complex physical, chemical, and biological processes occurring in these systems. Better modeling tools could assist in optimizing denitrifying wood chip bioreactors to meet nutrient reduction goals in urban and suburban watersheds.

Abstract S4-04: Tumor microenvironment of metastasis (TMEM) score is associated with early distant recurrence in hormone receptor (HR) positive, HER2-negative early stage breast cancer (ESBC)

Background: Metastasis is the primary cause of death in ESBC. We have shown in mouse models that a subpopulation of tumor cells expressing invasive Mena isoforms stream, form microanatomic structures (“TMEM”) with endothelial cells and macrophages, intravasate into the circulation at TMEM sites, and metastasize (Harney et al. Cancer Discovery, 2015). Further, TMEM sites (“MetaSites”) are identifiable in human ESBC, and “MetaSite score” [MS] is positively associated with distant recurrence in HR+/HER2- ESBC independent of clinicopathologic features, including IHC4 (Rohan et al. JNCI 2014). Here we determined the association between MS and recurrence in an independent ESBC cohort (E2197; NCT00003519).

Methods: We evaluated primary tumors from 600 patients (median followup 14.8 years) with ESBC (weighted % = 50% T1, 54% N0, 46% N1) treated with surgery and 4 cycles of adjuvant chemotherapy (AC or AT) and endocrine therapy. Grade, ER, PR, and HER2, and Oncotype DX Recurrence Score (RS) were evaluated in central labs (Badve et al. JCO 2008), and MS was determined in a CLIA-certified lab using an analytically validated, fully automated digital pathology/image analysis method that identifies Mena expressing tumor cells in direct contact with CD68+ macrophages and CD31+ endothelial cells (ie, “TMEMs”, or “MetaSites”). The objectives were to determine the association between MS and distant relapse free interval (DRFI) and relapse free interval (RFI). Kaplan-Meier survival curves were used to estimate time-to-event distributions. Cox proportional hazards models were used to assess hazard ratio associated with MS while controlling for covariates, and allowing time-varying association with MS. Both Kaplan-Meier and Cox regression methods addressed stratified sampling by incorporating proper weights. All analyses were performed in R 3.2.3.

Results: MS ranged from 0-199; the weighted mean MS was lower in HR+/HER2- than TN (16.1 vs. 23.8, p=0.001) and HER2+ disease (26.2, p=0.003). MS was not associated with T or N status, and correlated poorly with RS (r=0.29). Proportional hazards models revealed a significant positive association between continuous MS and DRFI (p=0.001) and RFI (p=0.00006) in HR+/HER2- disease in years 0-5 (and by MS tertiles for DRFI [p=0.04] and RFI [p=0.01]), but not after year 5 or in TN or HER2+ disease. Proportional hazards models including clinical covariates (N0 vs. N1; T1 vs. T2; high vs. int. vs. low grade) also revealed significant positive associations for continuous MS with RFI (p=0.04), and borderline association with DRFI (p=0.08). Similar findings for MS (RFI p=0.05;DRFI p=0.10) were noted in a joint model including categorical RS (&lt;18,18-30, &gt;30).

Conclusions: MS, a novel metastasis biomarker reflecting interaction between streaming and metastasizing tumor cells and microenvironment, provides prognostic information complementary to classical clinicopathologic features and RS in HR+/HER2- ESBC. Further evaluation is warranted in order to identify patients at highest risk of recurrence within 5 years most likely to benefit from adjuvant chemotherapy or novel therapies. (Supported by BCRF and NCI CA21115, CA180794, CA23318, CA66636, CA180820).

Citation Format: Sparano JA, Gray R, Oktay MH, Entenberg D, Rohan T, Xue X, Donovan M, Peterson M, Shuber A, Hamilton D, D'Alfonso T, Goldstein LJ, Gerlter F, Davidson N, Condeelis J, Jones J. Tumor microenvironment of metastasis (TMEM) score is associated with early distant recurrence in hormone receptor (HR) positive, HER2-negative early stage breast cancer (ESBC) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr S4-04.

Population-based cohort study of variation in the use of emergency cholecystectomy for benign gallbladder diseases

Background

The aims of this prospective population-based cohort study were to identify the patient and hospital characteristics associated with emergency cholecystectomy, and the influences of these in determining variations between hospitals.

Methods

Data were collected for consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing the performance of emergency cholecystectomy were analysed by means of multilevel, multivariable logistic regression modelling using a two-level hierarchical structure with patients (level 1) nested within hospitals (level 2).

Results

Data were collected on 4744 cholecystectomies from 165 hospitals. Increasing age, lower ASA fitness grade, biliary colic, the need for further imaging (magnetic retrograde cholangiopancreatography), endoscopic interventions (endoscopic retrograde cholangiopancreatography) and admission to a non-biliary centre significantly reduced the likelihood of an emergency cholecystectomy being performed. The multilevel model was used to calculate the probability of receiving an emergency cholecystectomy for a woman aged 40 years or over with an ASA grade of I or II and a BMI of at least 25·0 kg/m2, who presented with acute cholecystitis with an ultrasound scan showing a thick-walled gallbladder and a normal common bile duct. The mean predicted probability of receiving an emergency cholecystectomy was 0·52 (95 per cent c.i. 0·45 to 0·57). The predicted probabilities ranged from 0·02 to 0·95 across the 165 hospitals, demonstrating significant variation between hospitals.

Conclusion

Patients with similar characteristics presenting to different hospitals with acute gallbladder pathology do not receive comparable care.

Snapshots reflecting the lives of siblings of children with autism spectrum disorders

BACKGROUND

Past research focused on the effects of raising a child with autism spectrum disorder on families. However, most research examined parents' perspectives rather than siblings' perspectives. Therefore, the purpose of this qualitative descriptive design was to use photo elicitation to capture perspectives of siblings living with a child with autism spectrum disorder.

METHODS

Fourteen siblings (nine male) of 13 children with autism spectrum disorder received disposable cameras with 24-27 colour exposures, and were asked to photograph what was important to them within 2 weeks. After developing snapshots, investigators interviewed siblings about their photographs, and used open, axial and selective coding to determine photograph categories and subcategories.

RESULTS

Two major categories were found: people (family members, non-family members) and non-people (personal items/objects, animals, buildings, scenery). Interviews about photographs reflected experiences siblings had with people/non-people in the snapshots and their normal everyday activities. Most photographs revealed family life and activities any sibling would experience whether or not they lived in a family raising a child with autism spectrum disorder.

CONCLUSIONS

Photo elicitation facilitates communication between children and health-care professionals, and provides information about living with a child with autism spectrum disorder from the sibling's perspective. This information contributes to our knowledge base and allows development of specific intervention plans for siblings of these children.