Determinants of exposure to endocrine disruptors following hurricane Harvey.

Hurricane Harvey was a category four storm that induced catastrophic flooding in the Houston metropolitan area. Following the hurricane there was increased concern regarding chemical exposures due to damage caused by flood waters and emergency excess emissions from industrial facilities. This study utilized personal passive samplers in the form of silicone wristbands in Houston, TX to both assess chemical exposure to endocrine disrupting chemicals (EDCs) immediately after the hurricane and determine participant characteristics associated with higher concentrations of exposure. Participants from the Houston-3H cohort (n = 172) wore a wristband for seven days and completed a questionnaire to determine various flood-related and demographic variables. Bivariate and multivariate analysis indicated that living in an area with a high Area Deprivation Index (ADI) (indicative of low socioeconomic status), identifying as Black/African American or Latino, and living in the Houston neighborhoods of Baytown and East Houston were associated with increased exposure to EDCs. These results provide evidence of racial/ethnic and socioeconomic injustices in exposure to EDCs in the Houston Metropolitan Area. Since the multiple regression models conducted did not fully explain exposure (0.047 < R2 < 0.34), more research is needed on the direct sources of EDCs within this area to create effective exposure mitigation strategies.

Effects of stocking density on large white, commercial tom turkeys reared to 20 weeks of age: 1. growth and performance.

Industry standards for turkey stocking densities are variable and may not represent the more rapidly growing strains currently available. Therefore, a study was completed to evaluate 4 stocking densities: a nominal density (0.3525 m2/bird), 10% tighter density (0.3169 m2/bird), 10% looser density (0.3882 m2/bird), and 20% looser density (0.4238 m2/bird) on the effects on large white, commercial male turkeys with regard to performance from 5 to 20 wk of age. Brooding stocking density was fixed for all pens of birds with 60 birds per replicate pen at 0.46 m2/bird to 5 wk of age. Density treatments were applied from 5 to 20 wk by altering pen size with pen population held constant at 60 per pen. There were 4 pens of birds per density treatment. Birds were weighed individually at 0, 5, and 20 wk of age and performance parameters were calculated. There were no differences in bird performance at 5 wk, which was expected because stocking density was fixed. From 5 to 20 wk and at 20 wk, birds that were reared at the nominal standard (0.3525 m2/bird) and 10% tighter density (0.3169 m2/bird) had significantly lower body weight compared with the 10% looser density (0.3882 m2/bird) and 20% looser density (0.4238 m2/bird) (P = 0.03 and 0.01, respectfully). The feed conversion ratio (FCR) tended (P = 0.08) to be improved for birds reared at looser density. In addition, based on linear regression, as stocking density decreased (i.e., m2/bird increased), BW (P < 0.05) increased, and FCR (P = 0.10) tended to decrease (improve) at 20 wk. It was concluded that birds reared at looser density had improved performance.

Indoor versus Outdoor Air Quality during Wildfires.

The human behavioral modification recommendations during wildfire events are based on particulate matter and may be confounded by the potential risks of gas-phase pollutants such as polycyclic aromatic hydrocarbons (PAHs). Moreover, the majority of adults spend over 90 percent of their time indoors where there is an increased concern of indoor air quality during wildfire events. We address these timely concerns by evaluating paired indoor and outdoor PAH concentrations in residential locations and their relationship with satellite model-based categorization of wildfire smoke intensity. Low-density polyethylene passive air samplers were deployed at six urban sites for 1 week in Eugene, Oregon with matched indoor and outdoor samples and 24 h time resolution. Samples were then quantitatively analyzed for 63 PAH concentrations using gas-chromatography-tandem mass spectrometry. A probabilistic principal components analysis was used to reduce all 63 PAHs into an aggregate measure. Linear regression of the first principal component against indoor versus outdoor shows that indoor gas-phase PAH concentrations are consistently equal to or greater than outdoor concentrations. Regression against a satellite-based model for wildfire smoke shows that outdoor, but not indoor gas-phase PAH concentrations are likely associated with wildfire events. These results point toward the need to include gas-phase pollutants such as PAHs in air pollution risk assessment.

Organophosphorus pesticide degradation product in vitro metabolic stability and time-course uptake and elimination in rats following oral and intravenous dosing.

Levels of urinary dialkylphosphates (DAPs) are currently used as a biomarker of human exposure to organophosphorus insecticides (OPs). It is known that OPs degrade on food commodities to DAPs at levels that approach or exceed those of the parent OP. However, little has been reported on the extent of DAP absorption, distribution, metabolism and excretion. The metabolic stability of O,O-dimethylphosphate (DMP) was assessed using pooled human and rat hepatic microsomes. Time-course samples were collected over 2 h and analyzed by LC-MS/MS. It was found that DMP was not metabolized by rat or pooled human hepatic microsomes. Male Sprague-Dawley rats were administered DMP at 20 mg kg(-1) via oral gavage and i.v. injection. Time-course plasma and urine samples were collected and analyzed by LC-MS/MS. DMP oral bioavailability was found to be 107 ± 39% and the amount of orally administered dose recovered in the urine was 30 ± 9.9% by 48 h. The in vitro metabolic stability, high bioavailability and extent of DMP urinary excretion following oral exposure in a rat model suggests that measurement of DMP as a biomarker of OP exposure may lead to overestimation of human exposure.

Regional-scale assessment of soil salinity in the Red River Valley using multi-year MODIS EVI and NDVI.

The ability to inventory and map soil salinity at regional scales remains a significant challenge to scientists concerned with the salinization of agricultural soils throughout the world. Previous attempts to use satellite or aerial imagery to assess soil salinity have found limited success in part because of the inability of methods to isolate the effects of soil salinity on vegetative growth from other factors. This study evaluated the use of Moderate Resolution Imaging Spectroradiometer (MODIS) imagery in conjunction with directed soil sampling to assess and map soil salinity at a regional scale (i.e., 10-10(5) km(2)) in a parsimonious manner. Correlations with three soil salinity ground truth datasets differing in scale were made in Kittson County within the Red River Valley (RRV) of North Dakota and Minnesota, an area where soil salinity assessment is a top priority for the Natural Resource Conservation Service (NRCS). Multi-year MODIS imagery was used to mitigate the influence of temporally dynamic factors such as weather, pests, disease, and management influences. The average of the MODIS enhanced vegetation index (EVI) for a 7-yr period exhibited a strong relationship with soil salinity in all three datasets, and outperformed the normalized difference vegetation index (NDVI). One-third to one-half of the spatial variability in soil salinity could be captured by measuring average MODIS EVI and whether the land qualified for the Conservation Reserve Program (a USDA program that sets aside marginally productive land based on conservation principles). The approach has the practical simplicity to allow broad application in areas where limited resources are available for salinity assessment.

Field trial and modeling of uptake rates of in situ lipid-free polyethylene membrane passive sampler.

Lipid-free polyethylene membrane tubing (LFT) has been further developed in response to a growing need for an inexpensive and simple time-integrative sampling device for dissolved hydrophobic contaminants in water. The LFT sampler is based on the diffusion of dissolved hydrophobic target compounds through the aqueous boundary layer and into the polyethylene membrane, mimicking uptake by organisms. We demonstrate through laboratory and field validation studies that LFT provided the same benefits as many other passive sampling devices, withoutthe potential of analytical interference from lipid impurities. A total of 370 LFTs and semipermeable membrane devices were deployed for 21 days in paired studies at highly urbanized, undeveloped, and two Superfund sites, representing several river conditions. A simple internal surrogate spiking method served as an in situ calibration indicator of the effects of environmental conditions on the uptake rates. A modified extraction method for the LFT increased recoveries while decreasing solvent use and labor compared to other organic extraction procedures. LFT sampling rates were estimated using ratios, in situ calibration and modeling for over 45 target analytes, including PAHs, PCBs, and pesticides.

Temporal bioavailability of organochlorine pesticides and PCBs.

Because PCBs and organochlorine pesticides continue to be of global concern, studies that address information gaps, such as factors and influences of spatial and temporal effects on contaminant bioavailability, are valuable. The present study focused on the spatial and temporal distribution of bioavailable organochlorine pesticides and PCBs in surface waters of a contaminated harbor. Passive sampling devices were intensively deployed adjacent to various land uses on the Willamette River, OR, including Portland Harbor and McCormick and Baxter Superfund sites, during summer and fall, extreme conditions, 2001-2004. An increase of bioavailable sigmaDDTs (sum of p,p'-DDT, p,p'-DDD, and p,p'-DDE) concentrations was strongly affected bythe local historic production of DDTs and temporal changes in river conditions. The increase of bioavailable p,p'-DDD and high DDD/DDE ratios observed during summer indicates conditions favoring anaerobic reductive processes. In contrast to sigmaDDTs, the bioavailable concentrations and daily loads of dieldrin and PCBs increased during fall, especially during episodic rainstorms. On the basis of the PCB congener profiles, PCB inputs from urban runoff /sewer overflows were considered likely current sources of bioavailable PCB into the Harbor. The exceedence of the U.S. national and Oregon water quality criteria was a function of the temporal variability of each bioavailable contaminant. This illustrates the impacts associated with temporal changes of bioavailable organochlorine distributions in surface waters and the significance of considering realistic temporal, bioavailability, and site-specific conditions in risk assessment and water quality management.

Bioaccumulation profiles of chemical contaminants in fish from the lower Willamette River, Portland Harbor, Oregon.

Twenty-five PCBs (polychlorinated biphenyls), 15 organochlorine (OC) pesticides, and mercury were determined in fish from the Willamette River in Oregon, including a Portland Harbor superfund site. Fish were collected during the summer of 2000 along a 20-mile stretch of the lower Willamette River. Concentrations of sumPCBs (sum of 25 individually determined PCB congeners) and sumDDTs (sum of p,p'-DDT, p,p'-DDE, and p,p'-DDD) in fish ranged from 14 to 530 and from 18 to 510 ng/g-wet weight, respectively. SumPCBs concentrations at all sites exceeded US EPA fish advisory's screening values. Hexachlorobiphenyl congener 153 was the most abundant of the PCBs detected and p,p'-DDE was the most abundant OC pesticide detected. Low levels of dieldrin were detected in fish at all sites with the highest concentration at the superfund site (4.6 ng/g-wet weight), while other OC pesticides tested were near or below detection limits (approximately 2 ng/g). In general, organic chemical contaminant concentrations were highest in fish from the superfund site and were lower further upriver. Smallmouth bass had the highest levels of OC compounds of three fish species examined. They also had the largest site-to-site variations whereas black crappie had little variation throughout the study area. Mercury levels in fish ranged from 13 to 520 ng/g. Historical fish residue data are limited from the Portland Harbor superfund site, what data is available is over a decade old, generally consisted of only a few fish (< or = 3) and analyses quantified only a few PCB congeners (< 3).

Family involvement in nursing homes: effects on stress and well-being.

While it is clear that families remain involved in the lives of loved ones following placement in a nursing home, little research has examined whether visiting and the provision of care has effects on the emotional stress and psychological well-being of family members. Utilizing pre-placement and post-placement data from the Caregiver Stress and Coping Study (n = 185) as well as a theoretical framework to delineate the manifestation of caregiver stress (i.e., the stress process model), the goal of this analysis was to determine whether frequency of visits and provision of personal and instrumental activities of daily living assistance following institutionalization were related to post-placement emotional distress, family conflict, and psychological well-being among family members. Following control of a wide array of pre-placement and post-placement covariates, multiple regression models found that visiting was negatively associated with post-placement role overload; moreover, the provision of instrumental activities of daily living help was negatively related to loss of intimate exchange at post-placement. The results suggest that family involvement following institutionalization may operate differently than when in the community, and add to the literature emphasizing the positive implications of family involvement in residential long-term care.

Bioavailable organochlorine pesticides in a semi-arid region of eastern Oregon, USA, as determined by gas chromatography with electron-capture detection.

A group of dissolved-bioavailable organochlorine (OC) pesticides and inorganic anions in water and total OC pesticides in sediments were measured in the Malheur Watershed, a semi-arid region in the western United States, over a 2-year period. OC pesticide levels were compared with those from a 1990 study of the lower section of the river, the most recent data available. After calculating the dissolved fraction from the 1990, study it seems that DDD and dieldrin levels have decreased in the water by 50-70%, while DDE and DDT have changed little. Although banned nearly 30 years ago, DDT is still persistent throughout the Malheur River basin/watershed because it was found in all water samples tested. All of the OC pesticides tested during the 2-year study are well below the criterion continuous concentration for aquatic community exposure as defined by the U.S. Environmental Protection Agency (EPA). OC pesticides appear to be decreasing, however, at lower Ontario there remains a human health risk (EPA Human Health Risk Water Quality Criteria) for DDT, because this criteria includes daily consumption of water and fish from the river. Overall, although the upper forest watershed sites have lower OC pesticide concentrations, they represent an important contribution to the total DDT load to this watershed, a source not previously acknowledged. The large increase in DDT and sigmaDDT between the Ontario sites may indicate a possible historical point source of contamination or historical preferential deposition of contamination. Normalized sediment (sigmaDDT/organic carbon) strongly correlates with dissolved water sigmaDDT.

Analgesia induced by chronic nicotine infusion in rats: differences by gender and pain test.

RATIONALE: Acute administration of nicotine induces analgesia with subsequent development of tolerance. In human studies, females are less sensitive to the analgesic effects of nicotine than males. Few previous animal studies have investigated analgesic effects of chronic nicotine administration or addressed gender differences. OBJECTIVES: To investigate whether chronic administration of nicotine induces analgesia in male and female rats as assessed by a battery of standard pain assays, if tolerance develops, and if hyperalgesia occurs following cessation of nicotine. METHODS: Nicotine (free base; 6 mg/kg/day i.v.) or saline was administered for 2 weeks via implanted osmotic pumps. Pain behavior was assessed before, during, and for 3 weeks after nicotine infusion by measuring tail flick latency, hot-plate latency, and thermal paw withdrawal latency. The paw-withdrawal threshold to non-noxious mechanical stimuli was also measured. Effects of nicotine infusion, gender, and time were assessed by three-way analyses of variance. RESULTS: Both male and female rats exhibited a comparable degree of analgesia in the hot-plate test with development of tolerance during the 2-week infusion period. Males, but not females, showed analgesia in the tail flick test. Analgesia was not observed for thermally evoked paw withdrawal in either males or females, nor did nicotine affect non-noxious mechanically evoked paw withdrawals. Males and females showed cessation of weight gain during the first week of nicotine infusion. CONCLUSIONS: Chronic nicotine-induced analgesia was confirmed in both male and female rats as assessed using the hot-plate test which reflects integrated pain behavior. Males, but not females, exhibited analgesia in a nociceptive withdrawal reflex test (tail flick), indicating that nicotine-induced analgesia may depend on both the type of pain test and gender. The lack of nicotine-induced analgesia assessed by the tail flick reflex test in female rats is consistent with recent human studies showing that nicotine reduces pain elicited by brief noxious cutaneous stimulation in male but not female subjects.

Nedocromil sodium inhibits canine adenovirus bronchiolitis in beagle puppies.

Nedocromil sodium is a nonsteroidal anti-inflammatory drug used to control asthmatic attacks. Our hypothesis is that nedocromil sodium inhibits virus-induced airway inflammation, a common trigger of asthma. We nebulized nedocromil sodium into beagle dogs (n = 10, mean +/- SEM ages: 149 +/- 13 days) before and after inoculation with canine adenovirus type 2 (CAV2). Control dogs (n = 10) received saline aerosols and were either infected with CAV2 (Sal/CAV2, n = 7, mean +/- SEM ages: 140 +/- 11 days) or were not infected (Sal/Sal, n = 3, ages: 143 +/- 0 days). All dogs were anesthetized with choralose (80 mg/kg i.v.), intubated, and mechanically ventilated. Pulmonary function tests and bronchoalveolar lavage (BAL) were performed using standard techniques. Pulmonary function tests revealed no significant change between the nedocromil sodium and non-nedocromil-treated groups. The percentage of infected bronchioles was quantitated as the number of inflamed airways of 40 bronchioles examined times 100 for each dog. Nedocromil-treated dogs had significantly (p < 0.05) less mucosal inflammation (mean +/- SEM, 39% +/- 5%), epithelial denudation (36% +/- 5%), and BAL neutrophilia (11 +/- 3) than did Sal/CAV2 dogs (51% +/- 6%, 57% +/- 4%, and 33% +/- 8%, respectively). We concluded that pretreatment with nedocromil sodium aerosols attenuated CAV2-induced airway inflammation in these beagle puppies.

Speciation of iodide, iodine, and iodate in environmental matrixes by inductively coupled plasma atomic emission spectrometry using in situ chemical manipulation.

Dissolved iodine, iodide, and iodate are determined in environmental matrixes by in situ chemical manipulation and inductively coupled plasma atomic emission spectrometry (ICPAES). The method uses equipment commonly available to most laboratories involved in environmental inorganic analysis. Total dissolved iodine, iodide, and iodate are determined by ICPAES using iodine vapor generation. Total iodine is determined directly by ICPAES after filtration. Total dissolved iodide (I-) is oxidized in situ to iodine by the addition of sodium nitrite in sulfuric acid in a simplified continuous flow manifold. Iodate is determined by prereduction at the instrument before analysis by the in situ oxidation ICPAES procedure. A standard nebulizer produces the gas-liquid separation of the total iodine, which is then quantified by ICPAES at 206.16 nm. The instrument detection limit for the iodine analysis was 0.04 microgram/mL. Recoveries from seawater, saltwater, and freshwater standard reference materials ranged from 85 to 118% and averaged 98%. For samples containing both iodine and iodide, the total is determined with in situ oxidation, iodine is determined without the oxidizing reagents, and iodine is calculated from the difference. For samples containing all 3 species, pre-reduction is used and the iodine and iodide concentrations are subtracted for quantitation of iodate. The analysis is selective for these 3 species (I-, I2, and IO3). A group of 20-30 samples may be analyzed and quantitated for all 3 individual, commonly occurring iodide species in less than 1 h. The procedure is considerably faster than any other reported techniques. This method is especially well-suited to the analysis of small environmental samples.

Intrathoracic and concurrent orthopedic injury associated with traumatic rib fracture in cats: 75 cases (1980-1998).

OBJECTIVE: To characterize rib, intrathoracic, and concurrent orthopedic injuries, and prognosis associated with traumatic rib fracture in cats. DESIGN: Retrospective study. ANIMALS: 75 cats. PROCEDURE: Medical records from January 1980 to August 1998 were examined for cats with traumatic rib fracture. Signalment, cause of trauma, interval from trauma to evaluation at a veterinary teaching hospital, referral status and date, method of diagnosis, duration of hospitalization, number and location of rib fractures, presence of flail chest, costal cartilage involvement, intrathoracic and concurrent orthopedic injury, and clinical outcome were reviewed. RESULTS: Median age was 3 years. Twenty-five (58%) cats with reported cause of trauma were injured by interaction with another animal. Forty-seven (78%) cats that were treated survived. Cats that died had a median duration of hospitalization of < 1 day. Ten (13%) cats had flail chest. Sixty-five (87%) cats had intrathoracic injury (median, 2 injuries). Nine (100%) cats without detected intrathoracic injury that were treated survived. Thirty-five (47%) cats had concurrent orthopedic injury. Cats with flail chest, pleural effusion, or diaphragmatic hernia were significantly more likely to die than cats without each injury. CONCLUSIONS AND CLINICAL RELEVANCE: Traumatic rib fracture in cats is associated with intrathoracic and concurrent orthopedic injury. Aggressive treatment of cats with traumatic rib fracture is warranted, because the prognosis is generally favorable. Diagnosis and treatment of intrathoracic injury associated with traumatic rib fracture in cats should precede management of concurrent orthopedic injury.

Determining the geographic origin of potatoes with trace metal analysis using statistical and neural network classifiers.

The objective of this research was to develop a method to confirm the geographical authenticity of Idaho-labeled potatoes as Idaho-grown potatoes. Elemental analysis (K, Mg, Ca, Sr, Ba, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, S, Cd, Pb, and P) of potato samples was performed using ICPAES. Six hundred eight potato samples were collected from known geographic growing sites in the U.S. and Canada. An exhaustive computational evaluation of the 608 x 18 data sets was carried out using statistical (PCA, CDA, discriminant function analysis, and k-nearest neighbors) and neural network techniques. The neural network classification of the samples into two geographic regions (defined as Idaho and non-Idaho) using a bagging technique had the highest percentage of correct classifications, with a nearly 100% degree of accuracy. We report the development of a method combining elemental analysis and neural network classification that may be widely applied to the determination of the geographical origin of unprocessed, fresh commodities.

Components of a calmodulin-dependent protein kinase cascade. Molecular cloning, functional characterization and cellular localization of Ca2+/calmodulin-dependent protein kinase kinase beta.

Ca2+/calmodulin-dependent protein kinases I and IV (CaMKI and CaMKIV, respectively) require phosphorylation on an equivalent single Thr in the activation loop of subdomain VIII for maximal activity. Two distinct CaMKI/IV kinases, CaMKKalpha and CaMKKbeta, were purified from rat brain and partially sequenced (Edelman, A. M., Mitchelhill, K., Selbert, M. A., Anderson, K. A., Hook, S. S., Stapleton, D., Goldstein, E. G., Means, A. R., and Kemp, B. E. (1996) J. Biol. Chem. 271, 10806-10810). We report here the cloning and sequencing of cDNAs for human and rat CaMKKbeta, tissue and regional brain localization of CaMKKbeta protein, and mRNA and functional characterization of recombinant CaMKKbeta in vitro and in Jurkat T cells. The sequences of human and rat CaMKKbeta demonstrate 65% identity and 80% similarity with CaMKKalpha and 30-40% identity with CaMKI and CaMKIV themselves. CaMKKbeta is broadly distributed among rat tissues with highest levels in CaMKIV-expressing tissues such as brain, thymus, spleen, and testis. In brain, CaMKKbeta tracks more closely with CaMKIV than does CaMKKalpha. Bacterially expressed CaMKKbeta undergoes intramolecular autophosphorylation, is regulated by Ca2+/CaM, and phosphorylates CaMKI and CaMKIV on Thr177 and Thr200, respectively. CaMKKbeta activates both CaMKI and CaMKIV when coexpressed in Jurkat T cells as judged by phosphorylated cAMP response element-binding protein-dependent reporter gene expression. CaMKKbeta activity is enhanced by elevation of intracellular Ca2+, although substantial activity is observed at the resting Ca2+ concentration. The strict Ca2+ requirement of CaMKIV-dependent phosphorylation of cAMP response element-binding protein, is therefore controlled at the level of CaMKIV rather than CaMKK.

Neuromuscular blocking and cardiovascular effects of Org 9487, a new short-acting aminosteroidal blocking agent, in anaesthetized animals and in isolated muscle preparations.

This study was undertaken to investigate the neuromuscular blocking profile and cardiovascular effects of Org 9487, a new aminosteroidal, non-depolarizing, neuromuscular blocking agent structurally related to vecuronium, in anaesthetized animals and in isolated muscle preparations. In in vitro functional assays of neuromuscular blocking activity, Org 9487 was between eight and 15 times less potent than vecuronium. In cats and monkeys the potency of Org 9487 was approximately one-seventh and one-twentieth, respectively, that of vecuronium. In both species, Org 9487 induced rapidly developing (onset times between 1.5 min and 1.9 min) neuromuscular paralysis, which was shorter-lasting than that of vecuronium and similar in time course to suxamethonium. The vagal: neuromuscular blocking dose ratio for Org 9487 was 3 and ganglion block was seen only at approximately 20 times the neuromuscular blocking dose. There was no evidence in the rat that Org 9487, administered at doses up to 3 mg kg-1, inhibited noradrenaline re-uptake. In anaesthetized dogs, Org 9487 (3 x 90% blocking dose) induced only relatively small and transient haemodynamic effects. The administration of clinically relevant doses of neostigmine or pyridostigmine shortened the time-course profile of Org 9487, even when administered during profound neuromuscular block. In animals, Org 9487 is a low potency, nondepolarizing neuromuscular blocking agent with a time course profile similar to that of suxamethonium. Although Org 9487 is less selective than vecuronium for the neuromuscular junction, it is unlikely to produce prohibitive cardiovascular side effects in man.

A signaling complex of Ca2+-calmodulin-dependent protein kinase IV and protein phosphatase 2A.

Stimulation of T lymphocytes results in a rapid increase in intracellular calcium concentration ([Ca2+]i) that parallels the activation of Ca2+-calmodulin-dependent protein kinase IV (CaMKIV), a nuclear enzyme that can phosphorylate and activate the cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB). However, inactivation of CaMKIV occurs despite the sustained increase in [Ca2+]i that is required for T cell activation. A stable and stoichiometric complex of CaMKIV with protein serine-threonine phosphatase 2A (PP2A) was identified in which PP2A dephosphorylates CaMKIV and functions as a negative regulator of CaMKIV signaling. In Jurkat T cells, inhibition of PP2A activity by small t antigen enhanced activation of CREB-mediated transcription by CaMKIV. These findings reveal an intracellular signaling mechanism whereby a protein serine-threonine kinase (CaMKIV) is regulated by a tightly associated protein serine-threonine phosphatase (PP2A).

Ca2+/calmodulin-dependent protein kinase IV and calcium signaling.

Ca2+/calmodulin dependent protein kinase IV (CaMKIV) is a multifunctional, serine-threonine protein kinase that is activated in the presence of increased intracellular calcium (Ca2+). CaMKIV is a potent mediator of Ca2+ induced gene expression, primarily through its ability to phosphorylate and activate transcription factors such as CREB. CaMKIV-dependent activation of CREB is a key event in the expression of genes involved in the processes of T-cell activation and neuronal long term potentiation. The focus of this review is to describe the biochemical regulation of CaMKIV and examine how CaMKIV activates transcription in response to calcium in both cell and animal models.

Determination of trace boron in microsamples of biological tissues.

A benign-by-design method for the determination of boron (B) in microsamples of biological tissues was developed. This is a simple, automated, microdigestion method. Use of reagents and generation of waste are minimized, and the use of toxic/hazardous reagents is eliminated as compared to currently available B methodology. Microsamples are accommodated by the method; 100-400 mg samples were used in this study. B is determined by inductively coupled plasma atomic emission spectrometry (ICPAES) at 249.678 nm. The instrument detection limit for B is 0.01 microgram/mL. Interference studies have been investigated for 21 common elements. Over 250 analyses of standard reference materials were analyzed during the study duration. Recoveries for a series of biological tissues, both plant and animal, ranged from 82-104%.