First North American fossil monkey and early Miocene tropical biotic interchange.

New World monkeys (platyrrhines) are a diverse part of modern tropical ecosystems in North and South America, yet their early evolutionary history in the tropics is largely unknown. Molecular divergence estimates suggest that primates arrived in tropical Central America, the southern-most extent of the North American landmass, with several dispersals from South America starting with the emergence of the Isthmus of Panama 3-4 million years ago (Ma). The complete absence of primate fossils from Central America has, however, limited our understanding of their history in the New World. Here we present the first description of a fossil monkey recovered from the North American landmass, the oldest known crown platyrrhine, from a precisely dated 20.9-Ma layer in the Las Cascadas Formation in the Panama Canal Basin, Panama. This discovery suggests that family-level diversification of extant New World monkeys occurred in the tropics, with new divergence estimates for Cebidae between 22 and 25 Ma, and provides the oldest fossil evidence for mammalian interchange between South and North America. The timing is consistent with recent tectonic reconstructions of a relatively narrow Central American Seaway in the early Miocene epoch, coincident with over-water dispersals inferred for many other groups of animals and plants. Discovery of an early Miocene primate in Panama provides evidence for a circum-Caribbean tropical distribution of New World monkeys by this time, with ocean barriers not wholly restricting their northward movements, requiring a complex set of ecological factors to explain their absence in well-sampled similarly aged localities at higher latitudes of North America.

Nanoscale surface reactions by laser irradiation of Al nanoparticles on MoO3 flakes.

Surface reactions between heated aluminum nanoparticles (Al NPs) and thin α-MoO3 sheets are investigated. Localized photothermal heating on Al NP clusters is provided by a Raman spectrometer laser, while enhanced heating rates and imaging resolution are enabled by the use of a plasmonic grating substrate. Prominent linear reaction zones extending from Al NPs in the 〈001〉 crystal direction are observed on the surface of the host MoO3 sheets after heating. Raman spectroscopy and x-ray diffraction indicate that α-Al2O3 is generated within these extended reacted regions, while AFM and SEM indicate that the topology of the reaction regions are indistinguishable from the MoO3 host. We hypothesize that these Al2O3 zones are formed by surface diffusion and subsequent sub-surface adsorption of heated Al adatoms along the low-energy 〈001〉 MoO3 direction. Understanding and controlling these reaction mechanisms could lead to enhanced combustion of Al/MoO3 nanothermite systems.

Early Miocene CO2 estimates from a Neotropical fossil leaf assemblage exceed 400 ppm.

PREMISE OF THE STUDY: The global climate during the early Miocene was warmer than the present and preceded the even warmer middle Miocene climatic optimum. The paleo-CO2 records for this interval suggest paradoxically low concentrations (<450 ppm) that are difficult to reconcile with a warmer-than-present global climate. METHODS: In this study, we use a leaf gas-exchange model to estimate CO2 concentrations using stomatal characteristics of fossil leaves from a late early Miocene Neotropical assemblage from Panama that we date to 18.01 ± 0.17 Ma via 238 U/206 Pb zircon geochronology. We first validated the model for Neotropical environments by estimating CO2 from canopy leaves of 21 extant species in a natural Panamanian forest and from leaves of seven Neotropical species in greenhouse experiments at 400 and 700 ppm. KEY RESULTS: The results showed that the most probable combined CO2 estimate from the natural forests and 400 ppm experiments is 475 ppm, and for the 700 ppm experiments is 665 ppm. CO2 estimates from the five fossil species exhibit bimodality, with two species most consistent with a low mode (528 ppm) and three with a high mode (912 ppm). CONCLUSIONS: Despite uncertainties, it is very likely (at >95% confidence) that CO2 during the late early Miocene exceeded 400 ppm. These results revise upwards the likely CO2 concentration at this time, more in keeping with a CO2 -forced greenhouse climate.

Cranial asymmetry in Eocene archaeocete whales and the evolution of directional hearing in water.

Eocene archaeocete whales gave rise to all modern toothed and baleen whales (Odontoceti and Mysticeti) during or near the Eocene-Oligocene transition. Odontocetes have asymmetrical skulls, with asymmetry linked to high-frequency sound production and echolocation. Mysticetes are generally assumed to have symmetrical skulls and lack high-frequency hearing. Here we show that protocetid and basilosaurid archaeocete skulls are distinctly and directionally asymmetrical. Archaeocete asymmetry involves curvature and axial torsion of the cranium, but no telescoping. Cranial asymmetry evolved in Eocene archaeocetes as part of a complex of traits linked to directional hearing (such as pan-bone thinning of the lower jaws, mandibular fat pads, and isolation of the ear region), probably enabling them to hear the higher sonic frequencies of sound-producing fish on which they preyed. Ultrasonic echolocation evolved in Oligocene odontocetes, enabling them to find silent prey. Asymmetry and much of the sonic-frequency range of directional hearing were lost in Oligocene mysticetes during the shift to low-frequency hearing and bulk-straining predation.

COVID-19 transmission in a resource dependent community with heterogeneous populations: An agent-based modeling approach.

Outbreaks of COVID-19 in crowded work locations led to mass infection events during the pandemic that stressed health capacity in rural communities. This led to disparate responses - either isolating and restricting workers to facilities and potentially amplifying spread between them, more intense community wide restrictions, or an acceptance of higher disease spread. An extreme case is the salmon fishery in Bristol Bay, Alaska, where fishermen, factory workers, and residents all interact during the summer fishing season. During the pandemic, policy measures were debated, including community mask mandates, restricting workers to their boats and factories, and even closing the valuable seasonal fishery. We develop an agent-based SIR model (ABM) to examine COVID-19 transmission in a resource-dependent community populated by distinct subgroups. The model includes a virus spreading within and between three heterogenous populations who interact with other members of their type in their home location, and with different types of agents when out in the community. We simulate various non-pharmaceutical interventions and vaccination rates across these groups. Results demonstrate the efficacy of non-pharmaceutical interventions and vaccinations, as well as tradeoffs between duration and intensity and tradeoffs between groups impacted by the outbreak. This ABM demonstrates the impact of public policy mechanisms on health outcomes in resource-dependent communities with distinct populations.

Associations of Percent Body Fat and Motor Skill Development in Preschool-Aged Children: National Youth Fitness Survey.

Background: Body composition and motor skill development are important for the engagement in physical activity and healthy development of children. This study examined the associations between body composition and motor skill development in 3- to 5-year-old children. Methods: Data from preschool-aged children (N = 342, 51% males) who participated in the 2012 National Youth Fitness Survey were analyzed. Skinfold measurements (subscapular, calf, and triceps) were taken and percent body fat (%BF) was calculated using sex-specific equations. Lean muscle mass and fat mass were also calculated. Motor skill development was determined by the Test of Gross Motor Development-2nd Edition. Regression analyses were performed to determine the associations among %BF and locomotor skills, object control skills, and overall gross motor quotient (GMQ), controlling for sex, race, and poverty index ratio. Results: Most children were classified as with underweight/healthy weight (69%) and 31% were either with overweight or obesity. Average %BF was 17.02% ± 0.27%. The standard scores for locomotor skills, object control skills, and GMQ were 9.99 ± 0.16, 8.52 ± 0.14, and 95.57 ± 0.68, respectively. These scores were considered average. Regression analyses indicated that neither the %BF nor sum of skinfolds was associated with locomotor skills (ß = -0.07 ± 0.05, p = 0.63; ß = -0.03 ± 0.03, p = 0.22), object control skills (ß = 0.03 ± 0.04, p = 0.55; ß = 0.00 ± 0.02, p = 0.87), or GMQ (ß = -0.13 ± 0.28, p = 0.63; ß = -0.09 ± 0.14, p = 0.52). Furthermore, neither lean muscle mass nor fat mass was related with any motor skill measure (p > 0.05). Conclusions: Using different measures of body composition may provide additional insight into associations between obesity and motor skill development in preschool-aged children. Given the inconsistent findings in the literature, additional research is needed to elucidate these associations.

The Test-Retest Reliability of the Bruininks-Oseretsky Test of Motor Proficiency-Short Form in Youth with Down Syndrome-A Pilot Study.

BACKGROUND: It is unclear whether assessments of motor proficiency are reliable for individuals with Down syndrome. The purpose of the study was to evaluate the test-retest reliability of the Bruininks-Oseretsky Test of Motor Proficiency-Short Form (BOT-2 SF) in youth with Down syndrome. METHODS: Ten youth (ages 13.1-20.7 years) with Down syndrome completed the BOT-2 SF (14 items) plus a standing long jump on two separate occasions. Intraclass correlation coefficients (ICC), 95% confidence intervals (CIs), and standard error of measurement (SEM) were calculated to determine the test-retest reliability of the BOT-2 SF and the standing long jump. RESULTS: The test-retest reliability of the BOT-2 SF overall scores and percentile rankings were considered excellent. The test-retest reliability of each of the subtests varied with classifications of poor (n = 5), fair to good (n = 6), and excellent (n = 4). CONCLUSION: Current evidence suggests that children with Down syndrome have reduced motor skills. However, there appears to be a lack of assessment tools that reliably evaluate the motor skills of this population. The results from this investigation suggest that the BOT-2-SF provides "excellent reliability" (≥0.75) to assess the motor skills in youth with Down syndrome.

Fc-dependent expression of CD137 on human NK cells: insights into "agonistic" effects of anti-CD137 monoclonal antibodies.

CD137 (4-1BB) is a costimulatory molecule that can be manipulated for the treatment of cancer and autoimmune disease. Although it is known that agonistic antibodies (mAbs) against CD137 enhance the rejection of murine tumors in a natural killer (NK) cell- and T cell-dependent fashion, the mechanism for NK dependence is poorly understood. In this study, we evaluated the ability of 2 different glycoforms of a chimerized antihuman CD137 mAb, an aglycosylated (GA) and a low fucose form (GG), to react with human NK cells. Both mAbs bound similarly to CD137 and partially blocked the interaction between CD137 and CD137 ligand. However, unlike GA mAb, immobilized GG mAb activated NK cells and enhanced CD137 expression. These effects were seemingly dependent on Fc interaction with putative Fc receptors on the NK-cell surface, as only the immobilized Fc-fragment of GG was required for CD137 expression. Furthermore, CD137 expression could be enhanced with antibodies directed against non-CD137 epitopes, and the expression levels directly correlated with patterns of Fc-glycosylation recognized to improve Fc interaction with Fc gamma receptors. Our data suggest that CD137 can be enhanced on NK cells in an Fc-dependent fashion and that expression correlates with phenotypic and functional parameters of activation.

Physical Activity and Cognitive Aspects of Self-Regulation in Preschool-Aged Children: A Systematic Review.

Previous research showed a positive relationship between physical activity and self-regulation in older children and adolescents, but few publications focused on young children. Therefore, the purpose of this review was to examine the impact of physical activity (PA) on the cognitive aspects of self-regulation (inhibition, attention, and working memory, in preschool-aged (3-6 years old) children. The following databases were searched for articles: PubMed, SPORTDiscus, PsycINFO, and ERIC. References of the reviewed papers were screened for the identification of additional articles to be included in the review. Randomized control trials were reviewed to assess the impact of PA interventions on the cognitive aspects of self-regulation. There were six articles included in this review. Each study assessed at least one cognitive aspect of self-regulation [attention (n = 4), working memory (n = 2), and inhibition (n = 5)]. Attention was the only aspect that consistently showed improvement as a result of the PA interventions (4 of 4 studies). Only one study showed a positive impact on working memory and 60% of studies (3 of 5 studies) reported a positive relationship between PA and inhibition. Overall, the findings from this review showed that a consistent relationship only existed between attention and PA. No clear relationships were evident between working memory and inhibition and PA.

Physical activity types and motor skills in 3-5-year old children: National Youth Fitness Survey.

OBJECTIVE: This study examined relationships between specific types of physical activity (PA) and motor skill development in preschool-aged children. DESIGN: This study was completed using a cross-sectional study design. METHODS: Data from children 3-5years old (N=342, 51% males) who participated in the 2012 National Youth Fitness Survey were analyzed. PA was measured using a questionnaire by parent report and motor skill development determined by Test of Gross Motor Development-2nd Edition (TGMD-2). Multiple regression analyses were conducted to examine the relationship between PA type and overall Gross Motor Quotient (GMQ) controlling for age, sex, race, and parental socioeconomic status. RESULTS: Commonly reported activities were running (43%), playing outdoor games (35%), and riding a bike (34%). Based on the standard scores, participants' motor skill development for Locomotor, Object Control, and overall GMQ were considered average. Participation in the following physical activities were positively associated with GMQ: riding a bike (ß (SE)=5.27 (2.02), p=0.02), scooter riding (ß (SE)=9.83 (2.59), p=0.002), swimming (ß (SE)=4.01 (1.17), p=0.004), and jumping on a trampoline (ß (SE)=7.45 (3.09), p=0.03). With the exception of riding a bike, the physical activities positively related to GMQ had a reported range of participation between 7-12%. CONCLUSIONS: Participation in specific physical activities was related to higher GMQ in preschool-aged children. Also, with the exception of riding a bike, the activities that the children participated in the most were not the same as the activities that were positively related to motor skill development.

FcgammaRIIIa polymorphisms and cetuximab induced cytotoxicity in squamous cell carcinoma of the head and neck.

PURPOSE: The interaction of Fc fragments of antibodies with the Fcgamma receptors is an essential checkpoint in antibody-dependent cellular cytotoxicity (ADCC). Specific polymorphisms at position 158 enhance FcgammaRIIIa affinity for IgG1 and are associated with improved clinical outcome in lymphoma patients treated with IgG1 anti-CD20 antibody. The role of ADCC in the therapeutic effects of the alpha-epidermal growth factor receptor (EGFR) mAb, cetuximab, in patients with squamous cell carcinoma of the head and neck (SCCHN) is poorly defined. We employed three SCCHN cell lines to test two hypotheses: (1) SCCHN is susceptible to cetuximab-mediated ADCC, (2) efficacy of ADCC is associated with polymorphisms at position 158 of FcgammaRIIIa. EXPERIMENTAL DESIGN: FcgammaRIIIa-158 polymorphisms were determined for healthy donors, and their purified NK cells were used as effector cells against three SCCHN cell lines in ADCC assays. Cytotoxicity levels were compared for each polymorphism class. Proliferation and cell cycle assays were done to examine the direct effects of cetuximab. RESULTS: Our results indicate that SCCHN is susceptible to cetuximab-mediated ADCC in vitro. NK cytotoxic efficiency correlates with donor 158-polymorphisms in FcgammaRIIIa. Overall cytotoxicity was greatest for individuals having a single V allele when compared to homozygous F/F individuals; the cumulative percent cytotoxicity for each polymorphism among the cell lines was 58.2% V/V, 50.6% V/F, and 26.1% F/F (P < 0.001). Additionally, the presence of a V allele correlated with superior natural cytotoxicity against NK sensitive targets. CONCLUSION: These data have both prognostic and therapeutic relevance and support the design of a prospective trial to determine the influence of FcgammaRIIIa polymorphisms on the clinical outcome of patients with SCCHN treated with alpha-EGFR mAbs.

Ultrasensitive detection of lipoarabinomannan with plasmonic grating biosensors in clinical samples of HIV negative patients with tuberculosis.

BACKGROUND: Timely diagnosis of tuberculosis disease is critical for positive patient outcomes, yet potentially millions go undiagnosed or unreported each year. Sputum is widely used as the testing input, but limited by its complexity, heterogeneity, and sourcing problems. Finding methods to interrogate noninvasive, non-sputum clinical specimens is indispensable to improving access to tuberculosis diagnosis and care. In this work, economical plasmonic gratings were used to analyze tuberculosis biomarker lipoarabinomannan (LAM) from clinical urine samples by single molecule fluorescence assay (FLISA) and compared with gold standard sputum GeneXpert MTB/ RIF, culture, and reference ELISA testing results. METHODS AND FINDINGS: In this study, twenty sputum and urine sample sets were selected retrospectively from a repository of HIV-negative patient samples collected before initiation of anti-tuberculosis therapy. GeneXpert MTB/RIF and culture testing of patient sputum confirmed the presence or absence of pulmonary tuberculosis while all patient urines were reference ELISA LAM-negative. Plasmonic gratings produced by low-cost soft lithography were bound with anti-LAM capture antibody, incubated with patient urine samples, and biotinylated detection antibody. Fluorescently labeled streptavidin revealed single molecule emission by epifluorescence microscope. Using a 1 fg/mL baseline for limit of detection, single molecule FLISA demonstrated good qualitative agreement with gold standard tests on 19 of 20 patients, including accurately predicting the gold-standard-negative patients, while one gold-standard-positive patient produced no observable LAM in urine. CONCLUSIONS: Single molecule FLISA by plasmonic grating demonstrated the ability to quantify tuberculosis LAM from complex urine samples of patients from a high endemic setting with negligible interference from the complex media itself. Moreover, agreement with patient diagnoses by gold standard testing suggests that single molecule FLISA could be used as a highly sensitive test to diagnose tuberculosis noninvasively.

Modularity of the rodent mandible: integrating bones, muscles, and teeth.

Summary Several models explain how a complex integrated system like the rodent mandible can arise from multiple developmental modules. The models propose various integrating mechanisms, including epigenetic effects of muscles on bones. We test five for their ability to predict correlations found in the individual (symmetric) and fluctuating asymmetric (FA) components of shape variation. We also use exploratory methods to discern patterns unanticipated by any model. Two models fit observed correlation matrices from both components: (1) parts originating in same mesenchymal condensation are integrated, (2) parts developmentally dependent on the same muscle form an integrated complex as do those dependent on teeth. Another fits the correlations observed in FA: each muscle insertion site is an integrated unit. However, no model fits well, and none predicts the complex structure found in the exploratory analyses, best described as a reticulated network. Furthermore, no model predicts the correlation between proximal parts of the condyloid and coronoid, which can exceed the correlations between proximal and distal parts of the same process. Additionally, no model predicts the correlation between molar alveolus and ramus and/or angular process, one of the highest correlations found in the FA component. That correlation contradicts the basic premise of all five developmental models, yet it should be anticipated from the epigenetic effects of mastication, possibly the primary morphogenetic process integrating the jaw coupling forces generated by muscle contraction with those experienced at teeth.

CD8+ memory T lymphocytes from bone marrow--immune function and therapeutic potential.

Immunity to previously encountered diseases is provided in large part by memory T lymphocytes, which may be subdivided based on phenotypic and functional differences, as well as the specific cellular compartments in which these cells reside. The bone marrow (BM) is a unique microenvironment that supports robust proliferation and recall responses of both "central" and "effector" memory T cells, particularly within the CD8+ T cell subset. The recent identification within human BM of a population of CD8+ effector memory T cells with hybrid phenotype and enhanced cytotoxic function has important implications for the development of future immunotherapies. Using activated BM CD8+ memory T cells for adoptive transfer or targeting such cells with tailored vaccines may improve the ability of these classic modalities to produce potent and long-lasting antigen-specific responses, ultimately leading to clinically significant control of viral and malignant diseases.

Joint Relationship Between Physical Activity, Weight Status, and Motor Skills in Children Aged 3 to 10 Years.

While the relationships between physical activity (PA), obesity, and motor skills have been independently examined by previous research, this study explored both independent and combined relationships between children's PA, weight status, and motor skills within a multiple regression analysis. We measured height and weight and calculated body mass index (BMI) z scores for 96 children (3-10 years of age). We measured motor skills using the Movement Assessment Battery for Children-2nd edition (MABC-2), and we measured PA levels through accelerometry. Children with more time in moderate and moderate-to-vigorous PA had higher Total motor skill scores on the MABC-2. Further, children with higher moderate PA levels had higher Balance scores and those with moderate-to-vigorous PA demonstrated higher Aiming and Catching scores. Among children with healthier BMIs, more time spent in PA, regardless of intensity, was related to higher Aiming and Catching scores. Among children with BMI scores suggestive of overweight/obesity, both moderate and moderate-to-vigorous PA were positively related to Balance scores. In conclusion, while BMI z scores were not directly related to motor skills, PA levels were positively related to motor skills, and weight status mediated the relationship between PA and specific components of motor skills.

Single-Molecule Surface Plasmon-Coupled Emission with Plasmonic Gratings.

The ability to image single molecules (SM) has been the dream of scientists for centuries, and because of the substantial recent advances in microscopy, individual fluorescent molecules can now be observed on a regular basis. However, the development of such imaging systems was not without dilemmas, such as the detection and separation of individual fluorescence emissions. One method to solve this problem utilized surface plasmon resonance (SPR) to enhance the emission intensity of SMs. Although enhancing the SM emission intensity has yielded promising results, this method does not fully utilize the unique plasmonic properties that could vastly improve the SM imaging capabilities. Here, we use SPR excitation as well as surface plasmon-coupled emission from a high-definition digital versatile disc grating structure to image and identify different fluorophores using the angular emission of individual molecules. Our results have important implications for research in multiplexed SM spectroscopy and SM fluorescence imaging.

Integrated Chronology, Flora and Faunas, and Paleoecology of the Alajuela Formation, Late Miocene of Panama.

The late Miocene was an important time to understand the geological, climatic, and biotic evolution of the ancient New World tropics and the context for the Great American Biotic Interchange (GABI). Despite this importance, upper Miocene deposits containing diverse faunas and floras and their associated geological context are rare in Central America. We present an integrated study of the geological and paleontological context and age of a new locality from Lago Alajuela in northern Panama (Caribbean side) containing late Miocene marine and terrestrial fossils (plants, invertebrates, and vertebrates) from the Alajuela Formation. These taxa indicate predominantly estuarine and shallow marine paleoenvironments, along with terrestrial influences based on the occurrence of land mammals. Sr-isotope ratio analyses of in situ scallop shells indicate an age for the Alajuela Formation of 9.77 ± 0.22 Ma, which also equates to a latest Clarendonian (Cl3) North American Land Mammal Age. Along with the roughly contemporaneous late Miocene Gatun and Lago Bayano faunas in Panama, we now have the opportunity to reconstruct the dynamics of the Central America seaway that existed before final closure coincident with formation of the Isthmus of Panama.

Evolutionary Patterns among Living and Fossil Kogiid Sperm Whales: Evidence from the Neogene of Central America.

Kogiids are known by two living species, the pygmy and dwarf sperm whale (Kogia breviceps and K. sima). Both are relatively rare, and as their names suggest, they are closely related to the sperm whale, all being characterized by the presence of a spermaceti organ. However, this organ is much reduced in kogiids and may have become functionally different. Here we describe a fossil kogiid from the late Miocene of Panama and we explore the evolutionary history of the group with special attention to this evolutionary reduction. The fossil consists of cranial material from the late Tortonian (~7.5 Ma) Piña facies of the Chagres Formation in Panama. Detailed comparison with other fossil and extant kogiids and the results of a phylogenetic analysis place the Panamanian kogiid, herein named Nanokogia isthmia gen. et sp. nov., as a taxon most closely related to Praekogia cedrosensis from the Messinian (~6 Ma) of Baja California and to Kogia spp. Furthermore our results show that reduction of the spermaceti organ has occurred iteratively in kogiids, once in Thalassocetus antwerpiensis in the early-middle Miocene, and more recently in Kogia spp. Additionally, we estimate the divergence between extant species of Kogia at around the late Pliocene, later than previously predicted by molecular estimates. Finally, comparison of Nanokogia with the coeval Scaphokogia cochlearis from Peru shows that these two species display a greater morphological disparity between them than that observed between the extant members of the group. We hypothesize that this reflects differences in feeding ecologies of the two species, with Nanokogia being more similar to extant Kogia. Nanokogia shows that kogiids have been part of the Neotropical marine mammal communities at least since the late Miocene, and gives us insight into the evolutionary history and origins of one of the rarest groups of living whales.

Preoperative ultrasound is worthwhile for reoperative parathyroid surgery.

OBJECTIVES/HYPOTHESIS: High-resolution ultrasound and sestamibi scanning are regarded as the first-line methods for preoperative localization of parathyroid adenomas. The utility of ultrasound in reoperative cases has been questioned because of concern that scarring will obscure normal tissue planes and vascularity that are critical to identification of an adenoma using this imaging modality. The purposes of the study were to evaluate the ability of high-resolution ultrasound to accurately localize parathyroid adenomas in the reoperative exploration and to identify any factors that influence its accuracy STUDY DESIGN: Retrospective chart review at a tertiary care academic medical center. METHODS: All patients seen in referral for parathyroid surgery between May 1994 and September 2002 underwent high-resolution ultrasound as their initial diagnostic test. Patients who subsequently underwent exploration were included in the study. Intraoperative and ultrasound findings were compared. RESULTS: One hundred forty-two patients were included, 116 without and 26 with prior exploration. The sensitivity and positive predictive value of ultrasound were 86.9% and 89.1%, respectively. These data were not significantly different in patients without (88.2% and 90%) and in patients with (80% and 84.2%) prior thyroid or parathyroid surgery. The overall accuracy was 79% with a false-negative rate of 11.3%. Thyroid nodularity was significantly more common (81.8%) in patients who had a false-positive or false-negative finding on ultrasound than in the total population (61.3%). CONCLUSION: High-resolution ultrasound is an accurate method for localizing parathyroid adenomas even in patients who have previously undergone parathyroid exploration. However, the presence of thyroid nodules can interfere with its accuracy.

L-Arginine Supplementation in Type II Diabetic Rats Preserves Renal Function and Improves Insulin Sensitivity by Altering the Nitric Oxide Pathway.

Rat studies demonstrated that type II diabetes mellitus (T2DM) decreases both the production and bioavailability of nitric oxide (NO). L-arginine (LA) provides the precursor for the production of NO. We hypothesized that LA dietary supplementation will preserve NO production via endothelial nitric oxide synthase (eNOS) causing renal microvascular vasodilation and increased glomerular blood flow and thus increasing glomerular filtration rate (GFR). This would impede the formation of reactive oxygen species which contributes to cell damage and death. LA supplementation preserved GFR in the treated diabetic rats compared to untreated diabetic rats. We provide evidence that this effect may be due to increased levels of eNOS and urinary cyclic guanosine monophosphate, which leads to renal microvascular vasodilation. Plasma nitrotyrosine was decreased in the LA treated rats; however, plasma nitrite levels remained unaffected as expected. Marked improvements in glucose tolerance were also observed in the LA treated diabetic rats. These results demonstrate that LA supplementation preserves NO activity and may delay the onset of insulin resistance and renal dysfunction during hyperglycemic stress. These results suggest the importance of the NO pathway in consequent renal dysfunction and in the development of insulin resistance in diabetic rats.