Acute phase proteins and pesticide exposure

Rare Opportunities for Insights Into Serotonergic Contributions to Brain and Bowel Disorders: Studies of the SERT Ala56 Mouse

Altered structure, expression, and regulation of the presynaptic serotonin (5-HT) transporter (SERT) have been associated with multiple neurobehavioral disorders, including mood disorders, obsessive-compulsive disorder (OCD), and autism spectrum disorder (ASD). Opportunities to investigate mechanistic links supporting these associations were spurred with the identification of multiple, rare human SERT coding variants in a study that established a male-specific linkage of ASD to a linkage marker on chromosome 17 which encompassed the location of the SERT gene (SLC6A4). We have explored the most common of these variants, SERT Ala56, in vitro and in vivo. Results support a tonic elevation of 5-HT transport activity in transfected cells and human lymphoblasts by the variant in vitro that leads to an increased 5-HT clearance rate in vivo when studied in the SERT Ala56 mouse model, along with altered sensitivity to SERT regulatory signaling pathways. Importantly, hyperserotonemia, or an elevated whole blood 5-HT, level, was found in SERT Ala56 mice, reproducing a well-replicated trait observed in a significant fraction of ASD subjects. Additionally, we found multiple biochemical, physiological, and behavioral alterations in the SERT Ala56 mice that can be analogized to those observed in ASD and its medical comorbidities. The similarity of the functional impact of the SERT Ala56 variant to the consequences of p38α MAPK activation, ascribed to the induction of a biased conformation of the transporter toward an outward-facing conformation, has resulted in successful efforts to restore normal behavioral and bowel function via pharmacological and genetic p38α MAPK targeting. Moreover, the ability of the inflammatory cytokine IL-1β to enhance SERT activity via a p38α MAPK-dependent pathway suggests that the SERT Ala56 conformation mimics that of a chronic inflammatory state, supporting findings in ASD of elevated inflammatory cytokine levels. In this report, we review studies of the SERT Ala56 variant, discussing opportunities for continued insight into how chronically altered synaptic 5-HT homeostasis can drive reversible, functional perturbations in 5-HT sensitive pathways in the brain and periphery, and how targeting the SERT regulome, particularly through activating pathways such as those involving IL-1β/p38α MAPK, may be of benefit for neurobehavioral disorders, including ASD.

Effects of Environmental Pollutants on Cellular Iron Homeostasis and Ultimate Links to Human Disease

Chronic disease has increased in the past several decades, and environmental pollutants have been implicated. The magnitude and variety of diseases may indicate the malfunctioning of some basic mechanisms underlying human health. Environmental pollutants demonstrate a capability to complex iron through electronegative functional groups containing oxygen, nitrogen, or sulfur. Cellular exposure to the chemical or its metabolite may cause a loss of requisite functional iron from intracellular sites. The cell is compelled to acquire further iron critical to its survival by activation of iron-responsive proteins and increasing iron import. Iron homeostasis in the exposed cells is altered due to a new equilibrium being established between iron-requiring cells and the inappropriate chelator (the pollutant or its catabolite). Following exposure to environmental pollutants, the perturbation of functional iron homeostasis may be the mechanism leading to adverse biological effects. Understanding the mechanism may lead to intervention methods for this major public health concern.

Potency of andrographolide as an antitumor compound in BHC-induced liver damage

RELEVANCE

The present investigation relates to the influence of andrographolide, an active compound of Andrographis paniculata Nees. It reverses an experimental liver carcinogenic condition of mice to normal and might be a potential therapeutic/preventive agent for human liver cancer.

OBJECTIVE

A. paniculata (Kalmegh) is extensively used in the Indian traditional system of medicine as a hepatoprotective and hepatostimulative agent and has been reported to have protective effect against different hepatotoxins.

MATERIALS AND METHODS

Histomorphological, ultrastructural, and biochemical studies were performed for the effect of the andrographolide on control mice, mice treated with hexachlorocyclohexane (BHC) only and BHC + andrographolide. Enzymes for liver function tests were analyzed by spectrophotometric method.

RESULTS

The BHC experimental model forms an irreversible liver tumor in male mice. The histological and ultrastructural changes observed in andrographolide supplementation emphasize the recovery of the damaged liver. This recovery was also reflected in the neoplastic nodule formation. The activity of phosphorylase and glucose-6-phosphatase in the liver of the andrographolide-supplemented group suggests improved glycogenolysis in liver. Serum glutamate pyruvate transaminase, serum glutamate oxalate transaminase, alkaline phosphatase, acid phosphatase, and gamma-glutamyl transpeptidase showed a significant decrease in andrographolide-supplemented animals as compared with BHC-treated animals, suggesting regenerative effects elicited by andrographolide.

CONCLUSION

The study indicates that the regenerative capability elicited by andrographolide is possibly due to its ability to reactivate liver function enzymes that catalyze the reaction of several biochemical and synthetic processes and that it may be useful for severe liver damage conditions.

Suppression of mouse complement activity by contaminants of technical grade pentachlorophenol

Pentachlorophenol (PCP) is an antimicrobial agent used chiefly for the preservation of wood. Subchronic oral exposure (14 days) to Technical Grade PCP significantly inhibited the functional activity of female B6C3F1 mouse complement when measured in a microtiter hemolytic assay. When evaluated one day following the final exposure the highest administered dose (100 mg/kg) significantly suppressed the Classical complement pathway, the Spontaneous C1 autoactivation pathway, the Alternate pathway and the level of complement component, C3. Reconstitution studies using C5-deficient serum also demonstrated deleterious effects on this complement component. The Classical pathway was the most sensitive to Technical Grade PCP effects. Animals treated with 100 mg/kg Technical Grade PCP had CH 50 levels 30% of vehicle controls. Animals treated for 14 days and allowed a 15 day recovery period had CH 50 values 36% of control and animals which recovered for 30 days had only 52% of the complement activity of control animals. C3 recovery studies also demonstrated continued suppression on days 15 and 30 post-final exposure. Doses of 10 and 30 mg/kg did not produce the marked effects observed with the highest dose; however, a dose-dependent trend was observed for all responses. Animals treated with 100 mg/kg of EC-7, a PCP preparation with reduced amounts of contaminating dioxins and dibenzofurans, did not demonstrate detrimental effects on the complement system.

Health effects of chlorophenol wood preservatives on sawmill workers

At the request of the International Woodworkers of America, Local 1-85, woodworkers in two Port Alberni, British Columbia, sawmills were surveyed for health complaints possibly associated with chlorophenol exposure. On the basis of their exposure to anti-sapstain, workers were divided into low/moderate and high exposure groups. Health status was determined through a questionnaire that included lists of symptoms associated with exposure to chlorophenates and their contaminants. Extensive differences were found between exposure groups, especially in terms of the prevalence and extensiveness of symptoms related to dermatological, upper and general respiratory, and neurological structures and functions. Significant elevations of a wide range of other symptom complaints directly related to chemical exposure were also found. While improved spray control operations and the use of personal protective equipment will decrease injury among workers, they cannot be expected to decrease the hazards of chlorophenol exposure to an acceptable level. The only effective means of eliminating worker and public health risks attendant with these chemical exposures is to implement an alternative means of anti-sapstain treatment and to seek an end to the use of chlorophenol for this purpose.

Clinical findings in workers exposed to pentachlorophenol

Comparative findings are presented on the health and exposure status of groups of individuals in Hawaii with and without occupational exposure to pentachlorophenol (PCP). Occupational exposure to PCP occurred through employment at firms engaged in the treatment of wood with either PCP alone or PCP plus other compounds as preservative chemicals. Mean serum levels were 0.32 ppm for 32 control individuals, 1.72 ppm for 24 workers exposed to PCP and other wood preservative chemicals, and 3.78 ppm for 22 workers exposed to PCP as the sole preservative chemical. Age-standardized prevalence rates were significantly higher among the PCP-exposed than among the controls for low-grade infections or inflammations of the skin and subcutaneous tissue, protective membrane of the eyes and the mucosa membrane of the upper respiratory tract. Strong to moderate statistical associations were observed between PCP exposure and increased occurrence of bands (immature leucocytes) and basophils, increased plasma cholinesterase, alkaline phosphatase, gamma globulin and uric acid, and decreased serum calcium. Despite these statistical associations, laboratory values considered to be clinically abnormal were few and not significantly greater in occurrence among the PCP-exposed individuals.