Pseudo-pheochromocytoma due to obstructive sleep apnea: a case report

SUMMARY

Obstructive sleep apnea (OSA) is a condition of intermittent nocturnal upper airway obstruction. OSA increases sympathetic drive which may result in clinical and biochemical features suggestive of pheochromocytoma. We present the case of a 65-year-old male with a 2.9-cm left adrenal incidentaloma on CT, hypertension, symptoms of headache, anxiety and diaphoresis, and persistently elevated 24-h urine norepinephrine (initially 818 nmol/day (89-470)) and normetanephrine (initially 11.2 µmol/day (0.6-2.7)). He was started on prazosin and underwent left adrenalectomy. Pathology revealed an adrenal corticoadenoma with no evidence of pheochromocytoma. Over the next 2 years, urine norepinephrine and normetanephrine remained significantly elevated with no MIBG avid disease. Years later, he was diagnosed with severe OSA and treated with continuous positive airway pressure. Urine testing done once OSA was well controlled revealed complete normalization of urine norepinephrine and normetanephrine with substantial symptom improvement. It was concluded that the patient never had a pheochromocytoma but rather an adrenal adenoma with biochemistry and symptoms suggestive of pheochromocytoma due to untreated severe OSA. Pseudo-pheochromocytoma is a rare presentation of OSA and should be considered on the differential of elevated urine catecholamines and metanephrines in the right clinical setting.

LEARNING POINTS

Obstructive sleep apnea (OSA) is a common condition among adults. OSA may rarely present as pseudo-pheochromocytoma with symptoms of pallor, palpitations, perspiration, headache, or anxiety. OSA should be considered on the differential of elevated urine catecholamines and metanephrines, especially in patients with negative metaiodobenzylguanidine (MIBG) scan results.

Migratory Metrics of Wound Healing: A Quantification Approach for in vitro Scratch Assays

Metastatic dissemination generates an aggressive disease facilitated by enhanced migratory and invasive properties. Experimental approaches employ several in vitro and in vivo assays toward quantification of these functionalities. In vitro assessments of cell motility often employ endpoint assays that rely on the global efficacy of wound closure and thwart quantification of migratory phenotypes observed during metastatic dissemination. Recent studies highlight the distinct signatures associated with individual vs. collective cell migration and necessitate the incorporation of these modalities into routine analyses. Advances in live cell imaging that permit real-time visualization of pathophysiological processes can be employed toward elucidating phenotypic plasticity associated with cell migration to overcome caveats inherent to end-point assays. Herein, we corroborate live cell imaging with the in vitro scratch assay toward quantification of migratory modalities in transformed cells. Our protocol describes a step-by-step approach for live cell setup of the scratch assay, and details analyses employed toward definition of three quantitative metrics viz., displacement, velocity and number of nearest neighbors. The current protocol (from scratch induction to data acquisition) is implemented for ~30 h and provides global/single-cell resolution of migratory phenotypes as opposed to the endpoint assays. Routine application of this protocol in cancer biology can aid the design of therapeutic regimes targeting specific migratory modalities and significantly contribute to the dissection of associated molecular networks.

Confocal Microscopy Reveals Cell Surface Receptor Aggregation Through Image Correlation Spectroscopy

Confocal microscopy provides an accessible methodology to capture sub-cellular interactions critical for the characterization and further development of pre-clinical agents labeled with fluorescent probes. With recent advancements in antibody based cytotoxic drug delivery systems, understanding the alterations induced by these agents within the realm of receptor aggregation and internalization is of critical importance. This protocol leverages the well-established methodology of fluorescent immunocytochemistry and the open source FIJI distribution of ImageJ, with its inbuilt autocorrelation and image mathematical functions, to perform spatial image correlation spectroscopy (ICS). This protocol quantitates the fluorescent intensity of labeled receptors as a function of the beam area of the confocal microscope. This provides a quantitative measure of the state of target molecule aggregation on the cell surface. This methodology is focused on the characterization of static cells with potential to expand into temporal investigations of receptor aggregation. This protocol presents an accessible methodology to provide quantification of clustering events occurring at the cell surface, utilizing well established techniques and non-specialized imaging apparatus.

Genetic Evidence for Modifying Oceanic Boundaries Relative to Fiji

We present the most comprehensive genetic characterization to date of five Fijian island populations: Viti Levu, Vanua Levu, Kadavu, the Lau Islands, and Rotuma, including nonrecombinant Y (NRY) chromosome and mitochondrial DNA (mtDNA) haplotypes and haplogroups. As a whole, Fijians are genetically intermediate between Melanesians and Polynesians, but the individual Fijian island populations exhibit significant genetic structure reflecting different settlement experiences in which the Rotumans and the Lau Islanders were more influenced by Polynesians, and the other Fijian island populations were more influenced by Melanesians. In particular, Rotuman and Lau Islander NRY chromosomal and mtDNA haplogroup frequencies and Rotuman mtDNA hypervariable segment 1 region haplotypes more closely resemble those of Polynesians, while genetic markers of the other populations more closely resemble those of the Near Oceanic Melanesians. Our findings provide genetic evidence supportive of modifying regional boundaries relative to Fiji, as has been suggested by others based on a variety of nongenetic evidence. Specifically, for the traditional Melanesia/Polynesia/Micronesia scheme, our findings support moving the Melanesia-Polynesia boundary to include Rotuma and the Lau Islands in Polynesia. For the newer Near/Remote Oceania scheme, our findings support keeping Rotuma and the Lau Islands in Remote Oceania and locating the other Fijian island populations in an intermediate or "Central Oceania" region to better reflect the great diversity of Oceania.

Using Light Sheet Fluorescence Microscopy to Image Zebrafish Eye Development

Light sheet fluorescence microscopy (LSFM) is gaining more and more popularity as a method to image embryonic development. The main advantages of LSFM compared to confocal systems are its low phototoxicity, gentle mounting strategies, fast acquisition with high signal to noise ratio and the possibility of imaging samples from various angles (views) for long periods of time. Imaging from multiple views unleashes the full potential of LSFM, but at the same time it can create terabyte-sized datasets. Processing such datasets is the biggest challenge of using LSFM. In this protocol we outline some solutions to this problem. Until recently, LSFM was mostly performed in laboratories that had the expertise to build and operate their own light sheet microscopes. However, in the last three years several commercial implementations of LSFM became available, which are multipurpose and easy to use for any developmental biologist. This article is primarily directed to those researchers, who are not LSFM technology developers, but want to employ LSFM as a tool to answer specific developmental biology questions. Here, we use imaging of zebrafish eye development as an example to introduce the reader to LSFM technology and we demonstrate applications of LSFM across multiple spatial and temporal scales. This article describes a complete experimental protocol starting with the mounting of zebrafish embryos for LSFM. We then outline the options for imaging using the commercially available light sheet microscope. Importantly, we also explain a pipeline for subsequent registration and fusion of multiview datasets using an open source solution implemented as a Fiji plugin. While this protocol focuses on imaging the developing zebrafish eye and processing data from a particular imaging setup, most of the insights and troubleshooting suggestions presented here are of general use and the protocol can be adapted to a variety of light sheet microscopy experiments.

Absolute cardiovascular risk in a Fiji medical zone

BACKGROUND

The population of Fiji has experienced emergence of non-communicable disease (NCD) and a plateau in life expectancy over the past 20 years.

METHODS

A mini-STEPS survey (n = 2765) was conducted in Viseisei in Western Fiji to assess NCD risk factors (RFs) in i-Taukei (Melanesians) and those of Indian descent aged 25-64 years (response 73 %). Hypertension (HT) was defined as systolic blood pressure (BP) ≥140 mmHg or diastolic BP ≥90 mmHg or on medication for HT; type 2 diabetes mellitus (T2DM) as fasting plasma glucose ≥7.0 mmol/L or on medication for T2DM; and obesity as a body mass index (kilograms/height(metres)(2)) ≥30. Data were age-adjusted to 2007 Fiji Census. Associations between RFs and ethnicity/education were investigated. Comparisons with Fiji STEPS surveys were undertaken, and the absolute risk of a cardiovascular disease (CVD) event/death in 10 years was estimated from multiple RF charts.

RESULTS

NCD/RFs increased with age except excessive alcohol intake and daily smoking (women) which declined. Daily smoking was higher in men 33 % (95 % confidence interval: 31-36) than women 14 % (12-116); women were more obese 40 % (37-43) than men 23 % (20-26); HT was similar in men 37 % (34-40) and women 34 % (31-36), as was T2DM in men 15 % (13-17) and women 17 % (15-19). i-Taukei men had an odds ratio (OR) of 0.41 (0.28-0.58) for T2DM compared to Indians (1.00); and i-Taukei (both sexes) had a higher OR for obesity and low fruit/vegetable intake, daily smoking, excessive alcohol intake and HT in females. Increasing education correlated with lesser smoking, but with higher obesity and lower fruit/vegetable intake. Compared to the 2011 Fiji STEPS survey, no significant differences were evident in obesity, HT or T2DM prevalences. The proportion (40-64 years) classified at high or very high risk (≥20 %) of a CVD event/death (over 10 years) based on multiple RFs was 8.3 % for men (8.1 % i-Taukei, 8.5 % Indian), and 6.7 % for women (7.9 % i-Taukei, 6.0 % Indian).

CONCLUSIONS

The results of the survey highlight the need for individual and community interventions to address the high levels of NCD/RFs. Evaluation of interventions is needed in order to inform NCD control policies in Fiji and other Pacific Island nations.

Human adipose tissue expansion in pregnancy is impaired in gestational diabetes mellitus

AIMS/HYPOTHESIS

During pregnancy, adipose tissue (AT) must expand to support the growing fetus and the future nutritional needs of the offspring. Limited expandability of AT is associated with insulin resistance, attributed to ectopic lipid deposition. This study aimed to investigate human AT expandability during pregnancy and its role in the pathogenesis of gestational diabetes mellitus (GDM).

METHODS

This cross-sectional study of omental (OM) and subcutaneous (SQ) AT collected at Caesarean delivery included 11 pregnant and three non-pregnant women with normal glucose tolerance (NGT), five with GDM, three with type 2 diabetes mellitus. Adipocyte size, capillary density, collagen content and capillary growth were measured. Affymetrix arrays and real-time PCR studies of gene expression were performed.

RESULTS

Mean OM adipocyte size was greater in women with GDM than in those with NGT (p = 0.004). Mean OM and SQ capillary density was lower in GDM compared with NGT (p = 0.015). Capillary growth did not differ significantly between groups. The most differentially expressed AT transcript when comparing non-pregnant and pregnant women corresponded to the IGF binding protein (IGFBP)-5, the expression levels of which was found by subsequent quantitative real-time PCR to be lower in women with GDM vs women with NGT (p < 0.0001).

CONCLUSIONS/INTERPRETATION

The relative OM adipocyte hypertrophy and decreased OM and SQ capillary density are consistent with impaired AT expandability in GDM. The induction of adipose tissue IGFBP5 in pregnancy and its decrease in GDM point to the importance of the IGF-1 signalling pathway in AT expansion in pregnancy and GDM susceptibility.

Effects of herbivory, nutrients, and reef protection on algal proliferation and coral growth on a tropical reef

Maintaining coral reef resilience against increasing anthropogenic disturbance is critical for effective reef management. Resilience is partially determined by how processes, such as herbivory and nutrient supply, affect coral recovery versus macroalgal proliferation following disturbances. However, the relative effects of herbivory versus nutrient enrichment on algal proliferation remain debated. Here, we manipulated herbivory and nutrients on a coral-dominated reef protected from fishing, and on an adjacent macroalgal-dominated reef subject to fishing and riverine discharge, over 152 days. On both reefs, herbivore exclusion increased total and upright macroalgal cover by 9-46 times, upright macroalgal biomass by 23-84 times, and cyanobacteria cover by 0-27 times, but decreased cover of encrusting coralline algae by 46-100% and short turf algae by 14-39%. In contrast, nutrient enrichment had no effect on algal proliferation, but suppressed cover of total macroalgae (by 33-42%) and cyanobacteria (by 71% on the protected reef) when herbivores were excluded. Herbivore exclusion, but not nutrient enrichment, also increased sediment accumulation, suggesting a strong link between herbivory, macroalgal growth, and sediment retention. Growth rates of the corals Porites cylindrica and Acropora millepora were 30-35% greater on the protected versus fished reef, but nutrient and herbivore manipulations within a site did not affect coral growth. Cumulatively, these data suggest that herbivory rather than eutrophication plays the dominant role in mediating macroalgal proliferation, that macroalgae trap sediments that may further suppress herbivory and enhance macroalgal dominance, and that corals are relatively resistant to damage from some macroalgae but are significantly impacted by ambient reef condition.

A latent profile analysis of the typology of bulimic symptoms in an indigenous Pacific population: evidence of cross-cultural variation in phenomenology

BACKGROUND

Previous efforts to derive empirically based eating disorder (ED) typologies through latent structure modeling have been limited by the ethnic and cultural homogeneity of their study populations and their reliance on DSM-IV ED signs and symptoms as indicator variables.

METHOD

Ethnic Fijian schoolgirls (n=523) responded to a self-report battery assessing ED symptoms, herbal purgative use, co-morbid psychopathology, clinical impairment, cultural orientation, and peer influences. Participants who endorsed self-induced vomiting or herbal purgative use in the past 28 days (n=222) were included in a latent profile analysis (LPA) to identify unique subgroups of bulimic symptomatology.

RESULTS

LPA identified a bulimia nervosa (BN)-like class (n=86) characterized by high rates of binge eating and self-induced vomiting, and a herbal purgative class (n=136) characterized primarily by the use of indigenous Fijian herbal purgatives. Both ED classes endorsed greater eating pathology and general psychopathology than non-purging participants, and the herbal purgative class endorsed greater clinical impairment than either the BN-like or non-purging participants. Cultural orientation did not differ between the two ED classes.

CONCLUSIONS

Including study populations typically under-represented in mental health research and broadening the scope of relevant signs and symptoms in latent structure models may increase the generalizability of ED nosological schemes to encompass greater cultural diversity.

Development of a measure of "acculturation" for ethnic Fijians: methodologic and conceptual considerations for application to eating disorders research

Acculturation has been examined as a risk factor for eating disorders, but interpretation of findings has been limited by inconsistent operationalization of this construct across studies. The study aim was to develop and evaluate a population-specific measure of acculturation for ethnic Fijian adolescent schoolgirls, to use in future analyses related to eating disorders. Our findings suggest that acculturation is a multidimensional construct characterized by distinct, though related, dimensions of orientation to ethnic Fijian and/or western/global culture with respect to a range of behaviors and attitudes. In contrast to theoretical models positing uni-dimensional, orthogonal, or oblique relations between cultural identities in individuals undergoing acculturation, our study findings support a heterogeneous pattern among correlations of dimensions across contrasting cultural identities. We suggest multidimensional measures of acculturation are optimal--and socio-demographic proxies inadequate--for characterization of this complex process for health research.

Youth health-risk behavior assessment in Fiji: the reliability of Global School-based Student Health Survey content adapted for ethnic Fijian girls

OBJECTIVE

The Global School-based Student Health Survey (GSHS) is an assessment for adolescent health-risk behaviors and exposures, supported by the World Health Organization. Although already widely implemented - and intended for youth assessment across diverse ethnic and national contexts - no reliability data have yet been reported for GSHS-based assessment in any ethnicity or country-specific population. This study reports test-retest reliability for GSHS content adapted for a female adolescent ethnic Fijian study sample in Fiji.

DESIGN

We adapted and translated GSHS content to assess health-risk behaviors as part of a larger study investigating the impact of social transition on ethnic Fijian secondary schoolgirls in Fiji. In order to evaluate the performance of this measure for our ethnic Fijian study sample (n=523), we examined its test-retest reliability with kappa coefficients, % agreement, and prevalence estimates in a sub-sample (n=81). Reliability among strata defined by topic, age, and language was also examined.

RESULTS

Average agreement between test and retest was 77%, and average Cohen's kappa was 0.47. Mean kappas for questions from core modules about alcohol use, tobacco use, and sexual behavior were substantial, and higher than those for modules relating to other risk behaviors.

CONCLUSIONS

Although test-retest reliability of responses within this country-specific version of GSHS content was substantial in several topical domains for this ethnic Fijian sample, only fair reliability for the module assessing dietary behaviors and other individual items suggests that population-specific psychometric evaluation is essential to interpreting language and country-specific GSHS data.

Validity and reliability of a Fijian translation and adaptation of the Eating Disorder Examination Questionnaire

OBJECTIVE

Assessment of disordered eating has uncertain validity across culturally diverse populations. This study evaluated Eating Disorder Examination Questionnaire (EDE-Q) performance in an ethnic Fijian study population.

METHOD

The EDE-Q was translated, adapted, and administered to school-going Fijian adolescent females (N = 523). A subsample (n = 81) completed it again within approximately 1 week. We assessed feasibility, internal consistency, and test-retest reliability; evaluated construct validity through factor analysis and correlation with similar constructs; and examined the marginal utility of an additional question on traditional purgative use.

RESULTS

Internal consistency reliability was adequate for the global scale and subscales (Cronbach's alpha = 0.66-0.91); retest reliability was adequate for both the languages (range of ICCs, 0.50-0.79, and of kappas, 0.46-0.81, excluding purging items). Construct validity was supported by significant correlations with measures of similar constructs. Factor analysis confirms multiple dimensions of eating disorder symptoms but suggests possible culture-specific variation in this population. The majority of respondents endorsing traditional purgative use (58%) did not endorse conventional EDE-Q items assessing purging.

DISCUSSION

The EDE-Q is a valid measure of eating disorder pathology for ethnic Fijian adolescent females and measures a unitary underlying construct.

Adaptation and evaluation of the Clinical Impairment Assessment to assess disordered eating related distress in an adolescent female ethnic Fijian population

OBJECTIVE

Measurement of disease-related impairment and distress is central to diagnostic, therapeutic, and health policy considerations for eating disorders across diverse populations. This study evaluates psychometric properties of a translated and adapted version of the Clinical Impairment Assessment (CIA) in an ethnic Fijian population.

METHOD

The adapted CIA was administered to ethnic Fijian adolescent schoolgirls (N = 215). We calculated Cronbach's alpha to assess the internal consistency, examined the association between indicators of eating disorder symptom severity and the CIA to assess construct and criterion validity, and compared the strength of relation between the CIA and measures of disordered eating versus with measures of generalized distress.

RESULTS

The Fijian version of the CIA is feasible to administer as an investigator-based interview. It has excellent internal consistency (alpha = 0.93). Both construct and criterion validity were supported by the data, and regression models indicated that the CIA predicts eating disorder severity, even when controlling for generalized distress and psychopathology.

DISCUSSION

The adapted CIA has excellent psychometric properties in this Fijian study population. Findings suggest that the CIA can be successfully adapted for use in a non-Western study population and that at least some associated distress and impairment transcends cultural differences.

Breakfast skipping as a risk correlate of overweight and obesity in school-going ethnic Fijian adolescent girls

The prevalence of overweight and obesity has increased globally, and population data suggest that it is also increasing among ethnic Fijian youth. Among numerous behavioural changes contributing to overweight in youth residing in nations undergoing rapid economic and social change, meal skipping has not been examined as a potential risk factor. The study objectives were to assess the prevalence of overweight, obesity, and breakfast skipping and examine their cross-sectional association in a community sample of school-going ethnic Fijian adolescent girls (N=523). We measured height and weight, and assessed dietary patterns, eating pathology, dimensions of acculturation, and other socio-demographic and cultural data by self-report. We observed a high prevalence of both overweight (41%, including 15% who were obese) and breakfast skipping (68%). In addition, in multivariable analyses unadjusted for eating pathology, we found that more frequent breakfast skipping was associated with greater odds of overweight (odds ratio (OR)=1.15, confidence interval (CI)=1.06, 1.26, p<0.01) and obesity (OR=1.18, CI=1.05, 1.33, p<0.01). Regression models adjusting for eating pathology attenuated this relation so that it was non-significant, but demonstrated that greater eating pathology was associated with greater odds of both overweight and obesity. Future research is necessary to clarify the relation among breakfast skipping, eating pathology, and overweight in ethnic Fijian girls, and to identify whether breakfast skipping may be a modifiable risk factor for overweight in this population.

Beyond barcodes: complex DNA taxonomy of a South Pacific Island radiation

DNA barcodes can provide rapid species identification and aid species inventories in taxonomically unstudied groups. However, the approach may fail in recently diverged groups with complex gene histories, such as those typically found on oceanic islands. We produced a DNA-based inventory of taxonomically little known diving beetles (genus Copelatus) in the Fiji archipelago, where they are a dominant component of the aquatic invertebrate fauna. Sampling from 25 localities on five islands and analysis of sequences from one nuclear (328bp histone 3) and three mitochondrial (492bp rrnL, 786bp cox1, 333bp cob) gene regions revealed high haplotype diversity, mainly originated since the Pleistocene, and subdivided into three major phylogenetic lineages and 22 statistical parsimony networks. A traditional taxonomic study delineated 25 morphologically defined species that were largely incongruent with the DNA-based groups. Haplotype diversity and their spatial arrangement demonstrated a continuum of relatedness in Fijian Copelatus, with evidence for introgression at various hierarchical levels. The study illustrates the difficulties for formal classification in evolutionarily complex lineages, and the potentially misleading conclusions obtained from either DNA barcodes or morphological traits alone. However, the sequence profile of Fijian Copelatus provides an evolutionary framework for the group and a DNA-based reference system for the integration of ecological and other biodiversity data, independent of the Linnaean naming system.