Performance comparison of two Olympus InnovX handheld x-ray analyzers for feasibility of measuring arsenic in skin in vivo - Alpha and Delta models.

The Figure-Of-Merit (FOM) performance, a combination of detection limit and dose, is compared between two generations of handheld X-Ray Fluorescence (XRF) spectrometers for the feasibility of in vivo XRF measurement of arsenic (As) in skin. The Olympus InnovX Delta model analyzer (40 kVp using either 37 or 17µA) was found to show improvements in Minimum Detection Limit (MDL) using arsenic As-doped skin calibration phantoms with bulk tissue backing, when compared to the first generation InnovX Alpha model (40kVp, 20µA) in 120s measurements. Differences between two different definitions of MDL are discussed. On the Delta system, an MDL of (0.462±0.002) µg/g As was found in phantoms, with a nylon backing behind to mimic bulk tissue behind skin. The equivalent and effective doses were found to be (10±2) mSv and ~7×10-3µSv respectively for the Alpha and (15±4) mSv and ~8×10-3µSv respectively for the Delta system in 120s exposures. Combining MDL and effective dose, a lower (better) FOM was found for the Delta, (1.7±0.4) ppm mSv1/2, compared to (4.4±0.5) ppm mSv1/2 for the Alpha model system. The Delta analyzer demonstrates improved overall system performance for a rapid 2-min measurement in As skin phantoms, such that it can be considered for use in populations exposed to arsenic.

Feasibility of measuring arsenic and selenium in human skin using in vivo x-ray fluorescence (XRF)--a comparison of methods.

In recent years, in vivo measurement systems of arsenic in skin by K-shell x-ray fluorescence (XRF) have been developed, including one which was applied in a pilot study of human subjects. Improved tube-based approaches suggest the method can be further exploited for in vivo studies. Recently, it has been suggested that selenium deficiency is correlated with arsenic toxicity. A non-invasive measurement of both elements could therefore be of potential interest. The main aim of this current study was to evaluate and compare the performance of an upgraded portable XRF system and an advanced version of the benchtop XRF system for both selenium and arsenic. This evaluation was performed in terms of arsenic and selenium Kα detection limits for a 4W gold anode Olympus InnovX Delta portable analyzer (40 kVp) in polyester resin skin-mimicking phantoms. Unlike the polychromatic source earlier reported in the literature, the benchtop tube-based technique involves monochromatic excitation (25 W silver anode, manufactured by x-ray optics, XOS) and a higher throughput detector type. Use of a single exciting energy allows for a lower in vivo dose delivered and superior signal-noise ratio. For the portable XRF method, arsenic and selenium minimum detection limits (MDLs) of 0.59 ± 0.03 ppm and 0.75 ± 0.02 ppm respectively were found for 1 min measurement times. The MDLs for arsenic and selenium using the benchtop system were found to be 0.35 ± 0.01 ppm and 0.670 ± 0.004 ppm respectively for 30 min measurement times. In terms of a figure of merit (FOM), allowing for dose as well as MDL, the benchtop system was found to be superior for arsenic and the two systems were equivalent, within error, for selenium. We shall discuss the performance and possible improvements of each system, their ease of use and potential for field application.

Effect of sample preparation techniques on the concentrations and distributions of elements in biological tissues using µSRXRF: a comparative study.

Routine tissue sample preparation using chemical fixatives is known to preserve the morphology of the tissue being studied. A competitive method, cryofixation followed by freeze drying, involves no chemical agents and maintains the biological function of the tissue. The possible effects of both sample preparation techniques in terms of the distribution of bio-metals (calcium (Ca), copper (Cu) zinc (Zn), and iron (Fe) specifically) in human skin tissue samples was investigated. Micro synchrotron radiation x-ray fluorescence (µSRXRF) was used to map bio-metal distribution in epidermal and dermal layers of human skin samples from various locations of the body that have been prepared using both techniques. For Ca, Cu and Zn, there were statistically significant differences between the epidermis and dermis using the freeze drying technique (p = 0.02, p < 0.01, and p < 0.01, respectively). Also using the formalin fixed, paraffin embedded technique the levels of Ca, Cu and Zn, were significantly different between the epidermis and dermis layers (p = 0.03, p < 0.01, and p < 0.01, respectively). However, the difference in levels of Fe between the epidermis and dermis was unclear and further analysis was required. The epidermis was further divided into two sub-layers, one mainly composed of the stratum corneum and the other deeper layer, the stratum basale. It was found that the difference between the distribution of Fe in the two epidermal layers using the freeze drying technique resulted in a statistically significant difference (p = 0.012). This same region also showed a difference in Fe using the formalin fixed, paraffin embedded technique (p < 0.01). The formalin fixed, paraffin embedded technique also showed a difference between the deeper epidermal layer and the dermis (p < 0.01). It can be concluded that studies involving Ca, Cu and Zn might show similar results using both sample preparation techniques, however studies involving Fe would need more special attention.

Expression profile of the copper homeostasis gene, rAtox1, in the rat brain.

In humans the regulation of cellular copper homeostasis is essential for proper organ development and function. A novel cytosolic protein, named Atox 1, was recently identified in yeast that functions in shuttling intracellular mononuclear copper [Cu(I)] to copper-requiring proteins. Atox 1 and its human homolog, hAtox1, are members of an emerging family of proteins termed copper chaperones that are involved in the maintenance of copper homeostasis. Northern blot analysis demonstrates that Atox 1 is widely expressed at varying levels in a variety of rat tissues including brain. Using in situ hybridization histochemistry, we characterized the expression profile for the rat homolog of Atox1 (rAtox1) in the normal adult rat brain. There is widespread expression within the brain that appears to be primarily neuronal. The highest levels of Atox1 message consists of distinct neuronal subtypes that are also characterized by their high levels of metals like copper, iron, and zinc, which include the pyramidal neurons of the cerebral cortex and hippocampus in addition to the neurons of the locus coeruleus. The high levels of a metal chaperone like Atox1 in subsets of neurons that also sequester metals suggests that Atox1 may be important in maintaining the functionality of metal requiring enzymes. A detailed analysis of the restricted expression profile for a novel copper chaperone, rAtox1, is described in the adult rat CNS. Further analysis shows that Atoxl expression is associated with neuronal populations that sequester copper.

Simple strategy for direct identification of medically important yeast species from positive blood culture vials.

We compared direct inoculation of the Auxacolor yeast identification system from positive blood culture vials to standard identification with the API 20C AUX (API 20C), using 44 prospectively collected clinical specimens and 25 seeded blood culture vials. Direct inoculation of the Auxacolor system was accurate and more rapid than standard identification with the API 20C.

Evaluation of the auxacolor system for biochemical identification of medically important yeasts.

We compared the Auxacolor yeast identification system (Sanofi Diagnostics Pasteur) with the API 20C Aux (bioMerieux-Vitek) using 105 isolates of medically important yeasts. The Auxacolor system provided more rapid, accurate results and displayed less interobserver variability than the API 20C Aux.

Immunohistochemical localization of novel CART peptides in rat hypothalamus, pituitary and adrenal gland.

CART peptide specific polyclonal antisera were raised in rabbits. The antisera were raised to CART peptide fragments that span most of the predicted CART protein. The specificity of each antisera was demonstrated by blockade of immunostaining by the immunizing peptide but not by the other CART peptide fragments. In the hypothalamus and pituitary of colchicine and noncolchicine treated rats, immunostaining was observed in cell bodies, fibers and varicosities. Clusters of cells were also stained in the adrenal medulla. It is noteworthy that cellular immunostaining was only found in areas previously shown to express CART mRNA. These findings indicate the presence of CART peptide(s) in the hypothalamus, pituitary, and adrenal gland. Furthermore, we also present evidence for the possible processing of the CART pro-peptide into smaller peptide fragments. These neuroanatomical findings suggest a role of CART peptides in hypothalamic, pituitary and adrenal function.

Functional corticotropin-releasing factor receptors in human neuroblastoma cells.

The present study examined the presence of functional corticotropin-releasing factor (CRF) receptors in IMR-32 neuroblastoma cells. [125I]Tyro-ovine CRF binding was linear with increasing protein concentrations, saturable, reversible and of high affinity. Scatchard analysis indicated a Kd of approximately 0.8 nM and a Bmax of approximately 32 fmol/mg protein. Competition studies with CRF and related peptides revealed a pharmacological profile characteristic of the CRF1 receptor subtype. CRF stimulated cAMP production in a dose-dependent manner with an apparent EC50 of approximately 4 nM. In addition, the putative CRF receptor antagonist alpha-helical CRF9-41 dose-dependently inhibited CRF stimulated (10 nM) cAMP production with an IC50 of approximately 60 nM. CRF treatment down regulated its own receptor while treatment with the protein kinase C activator, phorbol 12-myristate 13-acetate (PMA), increased CRF binding in neuroblastoma cells. Taken together, these data demonstrate the utility of the human neuroblastoma cell line for functional studies on CRF receptors and suggest that CRF may play a regulatory role in the pathophysiology of human neuroblastoma.

Short- and long-term variability of echocardiographic stress-velocity indexes of cardiac function in a pediatric population.

This study determined the short- and long-term variability of stress-velocity relationships at end systole and peak systole. A prospective study during the short term (0 to 15 and 0 to 30 minutes) and long term (0 to 1 and 0 to 12 months) was performed calculating variability by the limits of agreement method. The study was performed in a tertiary-care pediatric echocardiographic laboratory. Twenty-five normal children underwent repeat testing as described. Standard blood pressure, carotid pulse tracing, and M-echocardiography of the left ventricle was performed at the intervals described. The rate-corrected mean velocity of fiber shortening (MVCFC), echocardiographic stress at end systole (SES), and echocardiographic stress at peak systole (SPS) were calculated for all recordings. The slopes of MVCFC-SES and MVCFC-SPS were determined by regression and plotted. With these slopes, the second and third stress values were normalized to the first stress value for the short and long term. The differences in normalized MVCFC and MVCFC (delta MVCFC) for 15 to 0 minutes, 30 to 0 months, 1 to 0 month, and 12 to 1 month were obtained for both SES and SPS, and 95% limits of agreement were estimated. The mean delta MVCFC for SES and SPS for the short and long term were not different from 0 or each other, indicating no bias. The 95% limits of agreement of delta MVCFCs (i.e., variability for SES at 15 to 0 minutes, 30 to 0 minutes, 1 to 0 month, and 12 to 0 month) were +/- 0.18, +/- 0.24, +/- 0.34, and +/- 0.27, respectively, and for SPS +/- 0.18, +/- 0.24, +/- 0.33, and +/- 0.28. Variability showed an increasing trend with time but was significant only from 15 to 0 minutes and 1 to 0 month (p = 0.006). This study has established short- and long-term variability in the stress-velocity relationship that is essential for monitoring acute and chronic changes in ventricular contractility in an individual patient.

Further study of the diagnostic and screening efficiency of the ST-Depression Adjective Check Lists.

In order to provide additional data on the diagnostic efficiency of the DACL in a situation in which dual diagnoses that involve depression also are considered, two groups of psychiatric patients completed DACL list E and independently were assigned psychiatric diagnoses via the Psychiatric Diagnostic Interview. Findings indicate that the DACL may be of considerable use in screening for depression. Sensitivity was high for both males and females (.84 and .80, respectively) with a cutting score of 12/13. Correct classification rates were also between 4 and 10% higher than base rates.

Insulin-dependent reduction in hepatic and splenic contents of interleukin-1 beta in experimental diabetes.

Interleukin-1 beta (IL-1 beta) is a polypeptide produced by a variety of cells of hematological, dermal and neural origin. We have investigated the effect of type I diabetes mellitus and insulin treatment on tissue levels of IL-1 beta using streptozotocin (STZ)-treated mouse as an animal model. Diabetes affected IL-1 beta in a tissue specific manner. For example, IL-1 beta levels (as measured by ELISA) were markedly decreased in the liver and spleen of the STZ diabetic mice. In contrast, the levels of this cytokine remained unalatered in other tissues including kidney, testis, hippocampus and pituitary. Insulin treatment restored the diabetes-related decreases in liver and spleen IL-1 beta levels. Overall, the present data suggest that the abnormalities in hepatic and splenic IL-1 beta levels may contribute, at least in part, to the immunodeficiency and increased susceptibility to infection in diabetes mellitus.

Norms, reliability, and concurrent validity measures of the Portuguese version of the Depression Adjective Check Lists.

This study reports normative data of depressive mood in Brazil, using a Portuguese version of the Depression Adjective Check Lists (DACL; Lubin, 1981, in press). Participants (N = 1,063) were college students drawn from randomly selected courses in 10 Brazilian universities. Cross-cultural comparisons showed that this Brazilian sample had significantly higher depressive scores compared to Hispanic (p < .01), American (p < .01), and Israeli (p < .05) samples. The results also indicated that Brazilian females (p < .05) and young adults (p < .05) reported significantly more depressive mood than males and older adults, respectively. All reliability (internal consistency, split-half, and alternate form) and concurrent validity measures were found to be appropriate and compared well to other cross-cultural samples.

Monoamine oxidase inhibitors inhibit [3H]quinpirole binding in rat striatal membranes.

This study describes interactions of monoamine oxidase inhibitors at binding sites labeled by [3H]quinpirole, a putatively selective ligand for dopamine D2-like receptors, in in vitro binding assays in rat brain. Monoamine oxidase inhibitors potently and competitively inhibited equilibrium binding of [3H]quinpirole in homogenate binding assays with the following rank order of potencies: clorgyline > or = Ro 41-1049 > pargyline > (-)-deprenyl > (+)-deprenyl > Ro 16-6491 > iproniazid. This rank order of potencies does not correlate with the potencies of these drugs at monoamine oxidase-A or monoamine oxidase-B, sigma site(s) or dopamine receptors. Monoamine oxidase inhibitors did not alter the ability of quinpirole to compete for [3H]spiperone binding. Quinpirole did not inhibit monoamine oxidase-A or monoamine oxidase-B activity and had low affinity (200 nM) for sigma site(s). These data suggest a potential novel binding site for [3H]quinpirole in rat brain and/or an alternative site of action for the antidepressant effects of monoamine oxidase inhibitors.

Differential pharmacological profile of striatal and cerebellar dopamine receptors labeled by [3H]quinpirole: identification of a discrete population of putative D3 receptors.

We have previously identified [3H]quinpirole-labeled dopamine receptors in the molecular layer of cerebellar lobule 10 which have a D2-like pharmacological profile, are guanine nucleotide-insensitive, and are juxtaposed to putative D3 receptor mRNA. This study compares the pharmacological profiles of [3H]quinpirole-labeled dopamine receptors in striatum and cerebellar lobule 10 using quantitative autoradiography. Dopaminergic compounds inhibited the specific binding of [3H]quinpirole in the caudate/putamen with the following rank order of potencies: spiperone > haloperidol > or = (+)butaclamol > or = quinpirole > or = 7-OH-DPAT > or = bromocriptine > clozapine > (-)sulpiride. In cerebellar lobule 10, a somewhat different rank order of potencies was observed: 7-OH-DPAT > quinpirole > or = bromocriptine > spiperone > (+)butaclamol > haloperidol > clozapine > (-)sulpiride. Quinpirole possessed equal affinity for [3H]quinpirole-labeled receptors in the caudate/putamen and cerebellum. 7-OH-DPAT exhibited 5-fold greater affinity for cerebellar receptors than those in the caudate/putamen. Spiperone, haloperidol, (+)butaclamol, and clozapine were more potent in competing for [3H]quinpirole binding at striatal dopamine receptors than cerebellar receptors by 83-, 59-, 11-, and 6-fold, respectively. The relative potencies of these compounds at striatal and cerebellar dopamine receptors are generally similar to the differential affinities reported at D2 and D3 dopamine receptors expressed in CHO cells, respectively. These data provide additional evidence that the dopamine receptors observed in cerebellar lobule 10 represent a discrete population of putative D3 receptors.

[3H]quinpirole binding to putative D2 and D3 dopamine receptors in rat brain and pituitary gland: a quantitative autoradiographic study.

The putative D2 dopamine receptor agonist quinpirole (LY 171,555) has been extensively used in a variety of in vivo and in vitro studies of D2 receptor-mediated effects and may have even higher affinity for the recently described D3 dopamine receptor. In the present study, conditions for autoradiographic visualization of [3H]quinpirole-labeled D2-like dopamine receptors were optimized and binding to slide-mounted sections was characterized with respect to pharmacology, guanine nucleotide sensitivity and regional distribution. The pharmacological profile of [3H]quinpirole binding in slide-mounted brain sections was: (+/-)-2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene > or = quinpirole > dopamine for putative dopamine agonists; spiperone > (+)-butaclamol > (-)-sulpiride > SCH 23390 >> cinanserin > (-)-butaclamol for antagonists. [3H]Quinpirole binding was decreased in the presence of guanine nucleotides in most brain regions except in the islands of Calleja and the molecular layer of cerebellar lobules 9 and 10. The regional distribution of [3H]quinpirole binding sites roughly paralleled the distribution of [3H]-(-)-sulpiride binding sites, with greatest densities present in the olfactory bulb glomerular layer, islands of Calleja, pituitary intermediate lobe, caudate/putamen, olfactory tubercles and nucleus accumbens. However, significantly greater densities of [3H]quinpirole binding than [3H]-(-)-sulpiride binding were observed in the molecular layer of cerebellar lobules 9 and 10, the islands of Calleja and olfactory bulb glomerular layer in concordance with the recently reported distribution of D3 receptor mRNA in these brain regions. Higher concentrations of [3H]quinpirole binding were also observed in the dorsomedial caudate and pituitary intermediate lobe. These data indicate the utility of [3H]quinpirole to label D3 as well as D2 dopamine receptors.

An ecological approach to evaluating a special education program.

This study provides further evidence of the value of ecobehavioral measurements in program evaluations, especially since past evaluations have focused on individual-level factors rather than ecological factors. Static (e.g., classroom materials) and dynamic (e.g., group interactions) features of the classroom environment were used to describe the impact of a special education program on 84 behaviorally disturbed adolescent males. The program outcomes assessed included increases in appropriate and decreases in inappropriate behaviors. The findings reveal that the program apparently accomplished its objectives. However, the ecobehavioral data also suggest that these students were mostly involved in busywork; that is, they were working by themselves with instructional materials rather than participating in interactive activities with the teacher or peers. Ecological issues related to increasing student motivation are addressed.

Characterization of [3H]quinpirole binding to D2-like dopamine receptors in rat brain.

The putative D2 dopamine receptor agonist quinpirole (LY 171,555) is the most widely used D2 agonist in in vivo and in vitro studies of D2 receptor-mediated effects. In addition, quinpirole may have even higher affinity for the recently described D3 dopamine receptor. The present study describes the in vitro binding properties of newly developed [3H]quinpirole in rat brain. [3H]Quinpirole binding was characterized in striatal membrane homogenate preparations using a filtration assay. Nonspecific binding was defined by 1 microM (+)-butaclamol. Specific [3H]quinpirole binding was saturable, and dependent on temperature, membrane concentration, sodium concentration and guanine nucleotides. Saturation analysis revealed high affinity binding characteristics (KD = 2.3 +/- 0.3 nM) which were confirmed by association-dissociation kinetics. The pharmacological profile of [3H]quinpirole binding in striatum was: (-)-N-n-propylnorapomorphine (+/-)-2-amino-6,7-dihydroxyl-1,2,3,4-tetrahydronaphthalene greater than or equal to quinpirole greater than apomorphine greater than bromocriptine greater than dopamine greater than SKF 38393 much greater than 5-hydroxytryptamine for putative dopamine agonists; spiperone greater than (+)-butaclamol greater than haloperidol greater than (-)-sulpiride greater than clozapine greater than SCH 23390 much greater than cinanserin for antagonists. [3H]Quinpirole binding exhibited stereoselectivity: (-)-sulpiride greater than (+)-sulpiride and (+)-butaclamol greater than (-)-butaclamol. This pharmacological profile is similar, though-not identical, to that observed for [3H] spiperone-labeled D2 receptors. The regional distribution of [3H]quinpirole binding sites roughly paralleled the distribution of [3H]spiperone binding sites, with greatest densities present in the striatum, nucleus accumbens and olfactory tubercles.(ABSTRACT TRUNCATED AT 250 WORDS)

Impairment of albuterol-induced suppression of food intake in diabetes mellitus.

Albuterol (salbutamol), a beta 2 adrenoreceptor agonist, produced a dose-dependent decrease in food intake in Sprague-Dawley male control rats. This phenomenon appeared to be impaired in streptozotocin (STZ) diabetic rats. The density of beta 2 adrenoreceptors in the ventromedial hypothalamic nucleus was increased as a function of diabetes. In contrast, a decrease in the ventromedial hypothalamic 5-hydroxyindoleacetic acid (5-HIAA) concentration, an indicator of serotonin (5-hydroxytryptamine; 5-HT) release or turnover rate, was observed in this disease state. Neither the beta 2 adrenoreceptor level nor 5-HT turnover rate was altered in the periventricular hypothalamic nucleus of STZ diabetic rats. The concentrations of 5-HT in both hypothalamic nuclei were unchanged in these animals. Neurochemical and behavioral abnormalities featured in the diabetic state were reversed with institution of insulin therapy. These data conclude that diabetes-related impairment in the anorexic action of albuterol may be due to derangements in ventromedial hypothalamic beta 2 adrenoreceptor function.

Demographics, affect, and adolescents' health behaviors.

Considerable research has established that a relationship exists between demographics, emotions, and physical health complaints. Much less is known about the association between demographics, affect, and actual health behaviors, particularly in youngsters. Accordingly, this paper presents findings on the relationship between affect, demographics, and health-related lifestyle among 139 public high school students, a population generally believed to be at high risk for the development of detrimental health habits. Covariation between affect, health practices, and demographics was examined using stepwise multiple regression analyses which revealed distinctive demographic and affective correlates of different health behaviors. The implications of these results are discussed and directions for future research are noted.