Recent Publications by CFE Educators

Pulse oximetry is a standard of care during anaesthesia in high-income countries. However, 70% of operating environments in low- and middle-income countries have no pulse oximeter. The 'Lifebox' oximetry project set out to bridge this gap with an inexpensive oximeter meeting CE (European Conformity) and ISO (International Organization for Standardization) standards. To date, there are no performance-specific accuracy data on this instrument. The aim of this study was to establish whether the Lifebox pulse oximeter provides clinically reliable haemoglobin oxygen saturation (Sp O2 ) readings meeting USA Food and Drug Administration 510(k) standards. Using healthy volunteers, inspired oxygen fraction was adjusted to produce arterial haemoglobin oxygen saturation (Sa O2 ) readings between 71% and 100% measured with a multi-wavelength oximeter. Lifebox accuracy was expressed using bias (Sp O2 - Sa O2 ), precision (SD of the bias) and the root mean square error (Arms). Simultaneous readings of Sa O2 and Sp O2 in 57 subjects showed a mean (SD) bias of -0.41% (2.28%) and Arms 2.31%. The Lifebox pulse oximeter meets current USA Food and Drug Administration standards for accuracy, thus representing an inexpensive solution for patient monitoring without compromising standards.

The principle neurons of the striatum are GABAergic medium spiny neurons (MSNs), whose collateral synapses onto neighboring neurons play critical roles in striatal function. MSNs can be divided by dopamine receptor expression into D1-class and D2-class MSNs, and alterations in D2 MSNs are associated with various pathological states. Despite overwhelming evidence for D2 receptors (D2Rs) in maintaining proper striatal function, it remains unclear how MSN collaterals are specifically altered by D2R activation. Here, we report that chronic D2R stimulation regulates MSN collaterals in vitro by presynaptic and postsynaptic mechanisms. We used corticostriatal cultures from mice in which MSN subtypes were distinguished by fluorophore expression. Quinpirole, an agonist for D2/3 receptors, was used to chronically activate D2Rs. Quinpirole increased the rate and strength of collateral formation onto D2R-containing MSNs as measured by dual whole-cell patch-clamp recordings. Additionally, these neurons were more sensitive to low concentrations of GABA and exhibited an increase in gephyrin puncta density, suggesting increased postsynaptic GABAA receptors. Last, quinpirole treatment increased presynaptic GABA release sites, as shown by increased frequency of sIPSCs and mIPSCs, correlating with increased VGAT (vesicular GABA transporter) puncta. Combined with the observation that there were no detectable differences in sensitivity to specific GABAA receptor modulators, we provide evidence that D2R activation powerfully transforms MSN collaterals via coordinated presynaptic and postsynaptic alterations. As the D2 class of MSNs is highly implicated in Parkinson's disease and other neurological disorders, our findings may contribute to understanding and treating the changes that occur in these pathological states.

BACKGROUND

There is a scarcity of evidence regarding outcomes of patients with follicular thyroid microcarcinoma and Hurthle cell microcarcinoma (1 cm); optimal treatment for these tumors remains unclear.

METHODS

Patients with follicular and Hurthle cell microcarcinomas, together (mFHCC), were selected from the Surveillance, Epidemiology, and End Results database (1988-2009) and compared with papillary thyroid microcarcinoma (mPTC). Data were analyzed with Chi-square tests, analysis of variance, the Kaplan-Meier method, log-rank tests, and Cox proportional hazards.

RESULTS

We identified 564 cases of mFHCC (371 mFTC and 193 mHCC) and 22,174 cases of mPTC. mFHCC had >8 times the rate of distant (extracervical) metastases compared with mPTC (4.1% vs. 0.5%; P .001). The 10-year disease-specific survival rate was decreased in mFHCC compared with mPTC (95.4% vs. 99.3%; P .001), and after adjustment, follicular or Hurthle cell histology remained an independent predictor of increased mortality (hazard ratio, 5.30; P .001). There was no difference in survival for patients who underwent total thyroidectomy versus thyroid lobectomy.

CONCLUSION

In comparison with mPTC, mFHCC is rare, presents more often with distant metastases, and patients have compromised survival. Additional studies are necessary in defining the extent of surgery and role of radioactive iodine for the treatment of mFHCC.

BACKGROUND

We report a patient with pantothenate kinase-associated neurodegeneration presenting as idiopathic basal ganglia calcifications, previously known as Fahr's disease.

METHODS

A teenage girl presented with slowly progressive dystonia. Her brain magnetic resonance imaging scan revealed T1 and T2 hypointensities in both globus pallidi, and no eye-of-the-tiger sign. Computed tomography showed dense globus pallidi calcifications. Metabolic evaluation was negative. The patient was diagnosed with idiopathic basal ganglia calcifications, a poorly understood syndrome of unknown cause. Whole exome sequencing was performed.

RESULTS

The patient was found to have two mutations in the pantothenate kinase 2 (PANK2) gene that have been previously associated with pantothenate kinase-associated neurodegeneration: a paternally inherited p.G521R and maternally inherited p.T528M. No deleterious changes were identified in genes associated with idiopathic basal ganglia calcifications or dystonia.

CONCLUSIONS

Pantothenate kinase-associated neurodegeneration should be considered in patients with idiopathic basal ganglia calcifications, especially when findings are confined to the globus pallidus.

Compared to proprioceptive afferent collateral projections, less is known about the anatomical, neurochemical, and functional basis of nociceptive collateral projections modulating lumbar central pattern generators (CPG). Quick response times are critical to ensure rapid escape from aversive stimuli. Furthermore, sensitization of nociceptive afferent pathways can contribute to a pathological activation of motor circuits. We investigated the extent and role of collaterals of capsaicin-sensitive nociceptive sacrocaudal afferent (nSCA) nerves that directly ascend several spinal segments in Lissauer's tract and the dorsal column and regulate motor activity. Anterograde tracing demonstrated direct multisegmental projections of the sacral dorsal root 4 (S4) afferent collaterals in Lissauer's tract and in the dorsal column. Subsets of the traced S4 afferent collaterals expressed transient receptor potential vanilloid 1 (TRPV1), which transduces a nociceptive response to capsaicin. Electrophysiological data revealed that S4 dorsal root stimulation could evoke regular rhythmic bursting activity, and our data suggested that capsaicin-sensitive collaterals contribute to CPG activation across multiple segments. Capsaicin's effect on S4-evoked locomotor activity was potent until the lumbar 5 (L5) segments, and diminished in rostral segments. Using calcium imaging we found elevated calcium transients within Lissauer's tract and dorsal column at L5 segments when compared to the calcium transients only within the dorsal column at the lumbar 2 (L2) segments, which were desensitized by capsaicin. We conclude that lumbar locomotor networks in the neonatal mouse spinal cord are targets for modulation by direct multisegmental nSCA, subsets of which express TRPV1 in Lissauer's tract and the dorsal column. J. Comp. Neurol. 521:2870-2887, 2013. © 2013 Wiley Periodicals, Inc.

OBJECTIVE We evaluated relationships of oral glucose tolerance testing (OGTT)-derived measures of insulin sensitivity and pancreatic β-cell function with indices of diabetes complications in a cross-sectional study of patients with type 2 diabetes who are free of overt cardiovascular or renal disease. RESEARCH DESIGN AND METHODS A subset of participants from the Penn Diabetes Heart Study (n = 672; mean age 59 ± 8 years; 67% male; 60% Caucasian) underwent a standard 2-h, 75-g OGTT. Insulin sensitivity was estimated using the Matsuda Insulin Sensitivity Index (ISI), and β-cell function was estimated using the Insulinogenic Index. Multivariable modeling was used to analyze associations between quartiles of each index with coronary artery calcification (CAC) and microalbuminuria. RESULTS The Insulinogenic Index and Matsuda ISI had distinct associations with cardiometabolic risk factors. The top quartile of the Matsuda ISI had a negative association with CAC that remained significant after adjusting for traditional cardiovascular risk factors (Tobit ratio -0.78 [95% CI -1.51 to -0.05]; P = 0.035), but the Insulinogenic Index was not associated with CAC. Conversely, the highest quartile of the Insulinogenic Index, but not the Matsuda ISI, was associated with lower odds of microalbuminuria (OR 0.52 [95% CI 0.30-0.91]; P = 0.022); however, this association was attenuated in models that included duration of diabetes. CONCLUSIONS Lower β-cell function is associated with microalbuminuria, a microvascular complication, while impaired insulin sensitivity is associated with higher CAC, a predictor of macrovascular complications. Despite these pathophysiological insights, the Matsuda ISI and Insulinogenic Index are unlikely to be translated into clinical use in type 2 diabetes beyond established clinical variables, such as obesity or duration of diabetes.

BACKGROUND

Laryngomalacia is the most common congenital laryngeal anomaly and is associated with several disorders including gastric reflux, sleep apnea, hypotonia and failure to thrive. Pectus excavatum (PE) is the most common chest wall deformity affecting 1-300/1000 individuals. Though many authors presume a relationship between PE and laryngomalacia, there is no published data to establish this association.

GOAL

To test the hypothesis that patients referred to our pediatric otolaryngology clinic for evaluation of laryngomalacia exhibit higher rates of PE than the general population.

METHODS

Retrospective review of prospectively enrolled children who presented with laryngomalacia (January 2008-June 2012) to a tertiary care, hospital based, pediatric otolaryngology practice. Each chart was examined for a concurrent diagnosis of pectus deformity.

RESULTS

Of the 137 laryngomalacia patients, 9 (6.6%) had documented PE. This represents a significantly increased rate of PE when compared to children without laryngomalacia (p = 0.001). Four of the 9 children with PE underwent supraglottoplasty for laryngomalacia, a significantly greater proportion than the 9/128 of the children with isolated laryngomalacia who underwent supraglottoplasty (p = 0.004).

CONCLUSIONS

This study suggests an association between laryngomalacia and PE. Pediatric otolaryngologists should be cognizant of this relationship, though further studies are needed to elucidate the nature of this association.