The P7C3 class of neuroprotective compounds exerts antidepressant efficacy in mice by increasing hippocampal neurogenesis.

Augmenting hippocampal neurogenesis represents a potential new strategy for treating depression. Here we test this possibility by comparing hippocampal neurogenesis in depression-prone ghrelin receptor (Ghsr)-null mice to that in wild-type littermates and by determining the antidepressant efficacy of the P7C3 class of neuroprotective compounds. Exposure of Ghsr-null mice to chronic social defeat stress (CSDS) elicits more severe depressive-like behavior than in CSDS-exposed wild-type littermates, and exposure of Ghsr-null mice to 60% caloric restriction fails to elicit antidepressant-like behavior. CSDS resulted in more severely reduced cell proliferation and survival in the ventral dentate gyrus (DG) subgranular zone of Ghsr-null mice than in that of wild-type littermates. Also, caloric restriction increased apoptosis of DG subgranular zone cells in Ghsr-null mice, although it had the opposite effect in wild-type littermates. Systemic treatment with P7C3 during CSDS increased survival of proliferating DG cells, which ultimately developed into mature (NeuN+) neurons. Notably, P7C3 exerted a potent antidepressant-like effect in Ghsr-null mice exposed to either CSDS or caloric restriction, while the more highly active analog P7C3-A20 also exerted an antidepressant-like effect in wild-type littermates. Focal ablation of hippocampal stem cells with radiation eliminated this antidepressant effect, further attributing the P7C3 class antidepressant effect to its neuroprotective properties and resultant augmentation of hippocampal neurogenesis. Finally, P7C3-A20 demonstrated greater proneurogenic efficacy than a wide spectrum of currently marketed antidepressant drugs. Taken together, our data confirm the role of aberrant hippocampal neurogenesis in the etiology of depression and suggest that the neuroprotective P7C3-compounds represent a novel strategy for treating patients with this disease.

Effect of cigarette menthol content on mainstream smoke emissions.

The 2009 Family Smoking Prevention and Tobacco Control Act empowered the U.S. Food and Drug Administration to study "the impact of the use of menthol in cigarettes on the public health, including such use among children, African Americans, Hispanics and other racial and ethnic minorities," and develop recommendations. Current scientific evidence comparing human exposures between menthol and nonmenthol smokers shows mixed results. This is largely because of the many differences between commercial menthol and nonmenthol cigarettes other than their menthol content. We conducted an innovative study using two types of test cigarettes: a commercial nonmenthol brand that we mentholated at four different levels, and Camel Crush, a commercial cigarette containing a small capsule in the filter that releases menthol solution into the filter when crushed. Cigarettes were machine-smoked at each of the menthol levels investigated, and the total particulate matter (TPM) was collected on a quartz fiber filter pad and analyzed by gas chromatography/mass spectrometry for menthol, nicotine, tobacco-specific nitrosamines (TSNAs), polycyclic aromatic hydrocarbons (PAHs), cotinine, and quinoline. The mainstream smoke was also monitored continuously in real time on a puff-by-puff basis for seven gas-phase constituents (acetaldehyde, acetonitrile, acrylonitrile, benzene, 1,3-butadiene, isoprene, and 2,5-dimethylfuran), using a proton transfer reaction-mass spectrometer. Average yields (in micrograms/cigarette) for the analytes were determined. Menthol in the TPM samples increased linearly with applied menthol concentration, but the amounts of nicotine along with the target TSNAs, PAHs, cotinine, and quinoline in the cigarettes remained essentially unchanged. Similarly, yields of the targeted volatile organic compounds (VOCs) in whole smoke from the mentholated nonmenthol cigarettes that were measured in real-time were largely unaffected by their menthol levels. In the Camel Crush cigarettes, however, the VOC yields appeared to increase in the presence of menthol, especially in the gas phase. Although we succeeded in characterizing key mainstream smoke constituents in cigarettes that differ only in menthol content, further study is needed to definitively answer whether menthol affects exposure to selected cigarette constituents and thereby influences harm.

Lung cancer and indoor air pollution in Xuan Wei, China.

In Xuan Wei County, Yunnan Province, lung cancer mortality is among China's highest and, especially in females, is more closely associated with indoor burning of "smoky" coal, as opposed to wood or "smokeless" coal, than with tobacco smoking. Indoor air samples were collected during the burning of all three fuels. In contrast to wood and smokeless coal emissions, smoky coal emission has high concentrations of submicron particles containing mutagenic organics, especially in aromatic and polar fractions. These studies suggested an etiologic link between domestic smoky coal burning and lung cancer in Xuan Wei.

Expression of three Rx homeobox genes in embryonic and adult zebrafish.

The paired-class homeobox gene, Rx, is important in eye development. In this study we analyze expression patterns of three zebrafish Rx genes (Zrx1, 2, 3) in embryos and adults. All three genes show dynamic spatiotemporal patterns of expression. Zrx3 is expressed earliest, in the anteriormost region of the neural plate, in regions that give rise to ventral diencephalon and retinae. As development proceeds, Zrx3 expression is reduced in the lateral optic primordia, and is absent in the optic cup, but is retained at the ventral midline of the diencephalon, and is expressed in hypothalamus in the adult. As the neural retina begins to differentiate, Zrx3 is re-expressed in a subset of cells in the inner nuclear layer, presumably bipolar cells, and this expression is retained in the adult. In contrast, Zrx1/2 have a slightly later onset of expression, are initially coincident with Zrx3, but then become complementary, remaining on in the optic primordia but disappearing from the ventral midline of the diencephalon. Zrx1/2 are down-regulated as the retina differentiates, except in the outer nuclear layer where they continue to be expressed at high levels in cone, but not rod, photoreceptors. This is the first transcription factor described that distinguishes between cone and rod photoreceptors.

Cadherin-4 expression in the zebrafish central nervous system and regulation by ventral midline signaling.

In this study we show that zebrafish cadherin-4 (R-cadherin) transcript (cad4) and protein are expressed in several defined regions in the embryonic forebrain and in distinctive clusters in the hindbrain and spinal cord. This is the first report of a segmental pattern of expression of cadherin-4 in the hindbrain and spinal cord. Expression domains of cadherin-4 transcript and protein were compared with that of pax6.1. In the forebrain of zebrafish embryos, cad4 and pax6.1 expression domains overlapped extensively, although they were not completely coincident. Injection of pax6.1 mRNA resulted in an increase in cad4 expression, whereas overexpression of sonic hedgehog (shh), a midline signaling molecule that reduces pax6.1 expression, caused a reduction in cad4 expression throughout the brain. cad4 expression was increased in both forebrain and hindbrain in cyclops mutant embryos, which have a defect in midline signaling and an enlarged expression domain of pax6.1. These results suggest that zebrafish cadherin-4 may play a role in organization of neuronal architecture throughout the neural axis, and that its expression is regulated by a ventral midline signaling pathway that involves shh and pax6.1.

Levels of persistent organic pollutants in several child day care centers.

The concentrations of a suite of persistent organic chemicals were measured in multiple media in 10 child day care centers located in central North Carolina. Five centers served mainly children from low-income families, as defined by the federal Women, Infants, and Children (WIC) assistance program, and five served mainly children from middle-income families. The targeted chemicals were chosen because of their probable carcinogenicity, acute or chronic toxicity, or hypothesized potential for endocrine system disruption. Targeted compounds included polycyclic aromatic hydrocarbons (PAHs), pentachloro- and nonyl-phenol, bisphenol-A, dibutyl and butylbenzyl phthalate, polychlorinated biphenyls (PCBs), organochlorine pesticides, the organophosphate pesticides diazinon and chlorpyrifos, and the herbicide 2,4-dichlorophenoxyacetic acid (2,4D). Sampled media were indoor and outdoor air, food and beverages, indoor dust, and outdoor play area soil. Concentrations of the targeted compounds were determined using a combination of extraction and analysis methods, depending on the media. Analysis was predominantly by gas chromatography/mass spectrometry (GC/MS) or gas chromatography with electron capture detection (GC/ECD). Concentrations of the targeted pollutants were low and well below the levels generally considered to be of concern as possible health hazards. Potential exposures to the target compounds were estimated from the concentrations in the various media, the children's daily time-activity schedules at day care, and the best currently available estimates of the inhalation rates (8.3 m(3)/day) and soil ingestion rates (100 mg/day) of children ages 3-5. The potential exposures for the target compounds differed depending on the compound class and the sampled media. Potential exposures through dietary ingestion were greater than those through inhalation, which were greater than those through nondietary ingestion, for the total of all PAHs, the phenols, the organophosphate pesticides, and the organochlorine pesticides. Potential exposures through dietary ingestion were greater than those through nondietary ingestion, which were greater than those through inhalation, for those PAHs that are probable human carcinogens (B2 PAH), the phthalate esters, and 2,4D. For the PCBs, exposures through inhalation were greater than those through nondietary ingestion, and exposures through dietary ingestion were smallest. Differences in targeted compound levels between the centers that serve mainly low-income clients and those that serve mainly middle-income clients were small and depended on the compound class and the medium.

Polycyclic aromatic hydrocarbon exposures of children in low-income families.

Children in low-income families may have high exposures to polycyclic aromatic hydrocarbons (PAH). Such exposures could result from household proximity to heavy traffic or industrial sources, environmental tobacco smoke, contaminated house dust or soil, among others. The objectives of this study were: to establish methods for measuring total PAH exposure of children in low-income families, to estimate the PAH exposures of these children, and to estimate the relative importance of the environmental pathways for PAH exposure. Analytical methods to determine PAH in air, dust, soil, and food and to determine hydroxy-PAH in urine samples were evaluated and validated. A two-home pilot study was conducted in downtown Durham, North Carolina (NC) during February 1994. One smoker's and one nonsmoker's household, which had preschool children and income at or below the official U.S. poverty level, participated. A nine-home winter and a nine-home summer study were conducted in Durham and the NC Piedmont area during February 1995 and August 1995, respectively. A summer study in four smokers' homes was also conducted. In each of these studies, multimedia samples were collected and analyzed for PAH or hydroxy-PAH. Summary statistics, Pearson correlations, and analysis of variance were performed on the combined data from these four field studies. An effective screening method was established for recruiting low-income families. The field protocol involved measurements of three homes in 2-day periods. This protocol should be suitable for large-scale studies. The results showed that indoor PAH levels were generally higher than outdoor PAH levels. Higher indoor PAH levels were observed in the smokers' homes compared to nonsmokers' homes. Higher outdoor PAH levels were found in inner city as opposed to rural areas. The relative concentration trend for PAH in dust and soil was: house dust > entryway dust > pathway soil. The PAH concentrations in adults' food samples were generally higher than those in children's food samples. Children's potential daily doses of PAH were higher than those of adults in the same household, when intakes were normalized to body weights. Inhalation is an important pathway for children's exposure to total PAH because of the high levels of naphthalene present in both indoor and outdoor air. Dietary ingestion and nondietary ingestion pathways became more important for children's exposure to the B2 PAH (ranked as probable human carcinogens, B2 by the U.S. EPA's Integrated Risk System), most of which are of low volatility. The analysis of variance results showed that inner city participants had higher total exposure to B2 PAH than did rural participants.

Evaluation of enzyme-linked immunosorbent assay for the determination of polycyclic aromatic hydrocarbons in house dust and residential soil.

Two commercially available enzyme-linked immunosorbent assays (ELISA) for total polycyclic aromatic hydrocarbon (PAH) and carcinogenic PAH (C-PAH) were evaluated. The testing procedures were refined for application to screening PAH and C-PAH in house dust and soil samples for human exposure studies. The overall method precision expressed as percent relative standard deviation (%RSD) of triplicate real world dust and soil samples was within +/- 29% (12-29%) for PAH ELISA and +/- 21% (5.9-21%) for C-PAH ELISA. Spike recoveries from real world dust/soil samples were 114 +/- 30% for phenanthrene from PAH ELISA and 120 +/- 8.2% for benzo[a]pyrene from C-PAH ELISA. The overall method accuracy for PAH and C-PAH assays cannot be assessed for multiple PAH components in dust/soil samples (which represent real-world samples), because of the assays' cross reactivities with other PAH components. Over 100 dust/soil samples from 13 North Carolina homes and 22 Arizona homes were analyzed by PAH and C-PAH assays, as well as by the conventional gas chromatography/mass spectrometry (GC/MS) method. Statistical analysis showed that dust/soil PAH data from ELISA and GC/MS methods are significantly different. In general PAH ELISA responses were higher than PAH GC/MS responses. The regression analysis showed that the linear relationship between ELISA and GC/MS measurements is not strong in the combined data. The relationship became stronger for the data from the same type of dust/soil samples. The screening performance of ELISA was evaluated based on the frequency distribution of ELISA and GC/MS data. The results indicated that the ELISA PAH and C-PAH assays cannot be used as a quantitative analytical tool for determining PAH in real-world dust/soil samples. However, the ELISA is an effective screening tool for ranking PAH concentrations in similar types of real world dust/soil samples.

Development of emission factors for polyamide processing.

Emission factors for selected volatile organic compounds (VOCs) and particulate material were developed during processing of commercial grades of polyamide 6, polyamide 66, and polyamide 66/6 resins. A small commercial-type extruder was used, and melt temperatures ranged from 475 to 550 degrees F. An emission factor was calculated for each substance measured and is reported as pounds released to the atmosphere per million pounds of polymer resin processed. Scaled to production volumes, these emission factors can be used by processors to estimate emission quantities from similar polyamide extrusion operations.

Development of emission factors for polycarbonate processing.

Emission factors for selected volatile organic compounds (VOCs) and particulate emissions were developed while processing eight commercial grades of polycarbonate (PC) and one grade of a PC/acrylonitrile-butadiene-styrene (ABS) blend. A small commercial-type extruder was used, and the extrusion temperature was held constant at 304 degrees C. An emission factor was calculated for each substance measured and is reported as pounds released to the atmosphere/million pounds of polymer resin processed [ppm (wt/wt)]. Scaled to production volumes, these emission factors can be used by processors to estimate emission quantities from similar PC processing operations.

Zebrafish genes rx1 and rx2 help define the region of forebrain that gives rise to retina.

Zebrafish retinal homeobox genes rx1 and rx2 are expressed exclusively in the optic primordia and then in cone photoreceptors of the differentiated neural retina. In this study, we show that the rx expression domain is coextensive with the region identified as the retinal field in published fate maps of the neural plate in zebrafish embryos. Analysis of the spatiotemporal relationships between retinal and forebrain precursors suggests that lateral movement of retinal precursors is responsible for evagination of the optic primordia. Overexpression of either rx1 or rx2 results in the loss of forebrain tissue and the ectopic formation of retinal tissue. We asked whether the deletion of forebrain and expansion of retinal tissue could be explained by the death of telencephalic precursors and enhanced proliferation of retinal precursors, and we found that it could not. Instead, our data are consistent with a change in cell fate of forebrain precursors associated with reduced expression of telencephalic markers (emx1 and BF-1) and ectopic expression of retinal markers (rx1/2/3, pax6, six6, and vsx2) at the neural keel stage. The rx homeodomain alone is sufficient to induce ectopic retinal tissue, although weakly so, and this observation, together with results from deletion constructs, suggests that interactions with unidentified transcriptional regulators are important for rx1 and rx2 function during early eye development. We conclude that regulated expression of zebrafish rx1 and rx2 helps to define the region of the forebrain fated to give rise to retinal tissue and may be involved in the cellular migrations that lead to splitting of the retinal field and formation of the optic primordia.

Modulation of lymphocyte proliferation by enzymes that degrade amino acids.

In a previous study we demonstrated thirteen amino acids to be essential and two to be partially essential for lymphocyte proliferation. Arginine is one of the essential amino acids, and the highly purified arginase strongly inhibited lymphocyte proliferation. The modulation of lymphocyte growth by various amino acid-degrading enzymes was studied. Peripheral lymphocytes were cultured in RPMI 1640 with or without amino acid-degrading enzyme for 72 h. A total of 17 commercial L-amino acid-degrading enzymes were studied. At 10 micrograms/ml, both lysine decarboxylase and asparaginase completely inhibited lymphocyte proliferation, arginase resulted in 78% inhibition and tyrosinase 57% inhibition. Other enzymes inhibited less than 20% lymphocyte proliferation; they included alanine dehydrogenase, arginine decarboxylase, aspartase, glutamic decarboxylase, glutamic dehydrogenase, glutaminase, histidase, histidine decarboxylase, leucine dehydrogenase, phenylalanine decarboxylase, phenylalanine hydroxylase, tryptophanase, and tyrosine decarboxylase. All four enzymes that strongly inhibited lymphocyte proliferation degraded amino acids that are essential for lymphocyte growth.

Modulation of human lymphocyte proliferation by amino acids.

The amino acids required for phytohaemagglutinin (PHA) induced lymphocyte proliferation were determined by the 3H-thymidine incorporation in amino acid-deficient media. Results indicate that the PHA-stimulated lymphocytes require alanine and serine in addition to 13 other amino acids present in Eagle's minimal essential medium (arginine, cysteine, glutamine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, tyrosine, and valine). The omission of any one of the 13 amino acids would stop almost completely the proliferation of PHA-stimulated lymphocytes. The omission of serine from RPMI 1640 medium caused a mean reduction of 64% of cell proliferation, while the addition of alanine to PRMI 1640 culture medium caused a mean increment of 52%. The lymphocyte proliferation appears to be modulated by amino acids in the culture medium, and for optimal growth of lymphocytes, all these 15 amino acids are essential.

Myositis ossificans progressiva mimicking ankylosing spondylitis: a case report.

Myositis ossificans progressiva is a rare disorder of young adults characterized by ossification of the connective tissue of the voluntary muscles and ligaments. Although it is trauma-related, up to 40-60% of these patients have no history of previous injury. A young female with marked kyphosis and ankylosis of the spine presented with a recent onset of a rapidly growing painful mass over the anterior aspect of her left shoulder. She received an excisional biopsy but recurrent ossification developed soon after. It then spread to the biceps muscle with subsequent contracture deformities of the shoulder and elbow joints. A plain radiogram of her spine revealed similar characteristics of ankylosing spondylitis. However, the final diagnosis was made by the pathognomonic ectopic ossification of muscles and para-articular soft tissue. Despite poor response of the established constracture, the painful mass did respond well to prednisolone treatment within 2 months, in terms of size and consistency.

Human exposure and dosimetry of polycyclic aromatic hydrocarbons in urine from Xuan Wei, China with high lung cancer mortality associated with exposure to unvented coal smoke.

The lung cancer mortality rate in Xuan Wei (XW) county, China, is 5-fold the national average of China; the rate for women is the highest in China. Xuan Wei residents have been exposed to unvented coal or wood smoke during cooking or heating in homes. This study investigated indoor air exposure and dosimetry of polycyclic aromatic hydrocarbons (PAHs) in XW residents using smoky coal. Indoor air particles collected during cooking in four XW homes using smoky coal were analyzed for PAHs by GC/MS. Urine samples from 16 XW non-smoking women and six XW smoking men, eight Kunming non-smoking controls and four non-smoking Chinese American controls were analyzed for PAHs and hydroxy-PAHs by GC/MS. The results showed that XW residents were exposed to PAHs at occupational levels. The potent carcinogen, dibenzo[a,l] pyrene (4.9 +/- 1.3 micrograms/m3) was found in the indoor air of the XW homes. The levels of urinary hydroxy-PAH were higher than those of the parent compounds in most subjects, indicating that most PAHs were metabolized. In urine, the mean levels of 9-hydroxy BaP (BaP) and BaP are 1.5 +/- 0.5 mumol/mol creatinine and 0.5 +/- 0.3 microns/mol for XW men, 1.9 +/- 0.9 microns/mol and 0.5 +/- 0.3 microns/mol for XW women. In general, the levels of PAH metabolites in urine were higher in the XW residents than in Kunming and Chinese American controls; however only the concentrations of 9-hydroxy BaP in XW women showed statistically significant difference from the Kunming controls (P < 0.05 by ranking test). The mean levels of 3 methylated-PAHs analyzed were 4.8-fold higher than that of the parent PAHs in XW subjects. This is consistent with previous findings that alkylated PAHs are the major mutagens in the XW indoor air and may be etiologically important in XW lung cancer.