The use of freshwater planarians in environmental toxicology studies: Advantages and potential.

Regarding the humane use of animals in scientific research, invertebrates are often recommended in toxicological studies. "Freshwater planarians" refers to numerous free-living freshwater members of the Class "Turbellaria" of the phylum Platyhelminthes. This group of invertebrates has received extensive attention from biologists for many years because of their unique biological characteristics, such as the primitive form of the central nervous system and notable capability to regenerate tissues.

Inhibitory effects of pain relief drugs on neurological enzymes: implications on their potential neurotoxicity to aquatic animals.

Pain relief medications commonly occur in the aquatic environment at measurable levels. While the neurotoxicity of pain relievers to higher vertebrates is currently known, little is known about their effects on aquatic animals. This study investigated the neurotoxicity of pain relievers to aquatic animals.

Disturbances to neurotransmitter levels and their metabolic enzyme activity in a freshwater planarian exposed to cadmium.

Using specific neurobehaviors as endpoints, previous studies suggested that planarian neurotransmission systems could be targets of Cd neurotoxicity. However, direct evidence for disturbed neurotransmission systems by Cd in treated planarians is still lacking. In planarians, dopamine (DA) and serotonin (5-HT) play critical roles in neuromuscular function, but little is known about their metabolic degradation.

Alterations of biochemical indicators in hepatopancreas of the golden apple snail, Pomacea canaliculata, from paddy fields in Taiwan.

The freshwater golden apple snail, Pomacea canaliculata, is one of the world's 100 worst invasive alien species. The snails' wide distribution, high abundance, and sensitivity to environmental pollution make them a potential bioindicator for environmental contamination. In this study, the biochemical status of golden apple snails collected from paddy fields throughout the island of Taiwan was examined.

Cadmium neurotoxicity to a freshwater planarian.

Although freshwater planarians are evolutionarily primitive, they are some of the simplest bilateral animals possessing integrated neural networks similar to those in vertebrates. We attempted to develop planarian Dugesia japonica as a model for investigating the neurotoxicity of environmental pollutants such as cadmium (Cd). This study was therefore designed to study the effects of Cd on the locomotor activity, neurobehavior, and neurological enzymes of D.

Photonic generation of ultra-wide-band doublet pulse through monolithic integration of tapered directional coupler and quantum well waveguide.

We proposed and demonstrated a novel scheme of photonic ultra-wide-band (UWB) doublet pulse based on monolithic integration of tapered optical-direction coupler (TODC) and multiple-quantum-well (MQW) waveguide. TODC is formed by a top tapered MQW waveguide vertically integrating with an underneath passive waveguide. Through simultaneous field-driven optical index- and absorption- change in MQW, the partial optical coupling in TODC can be used to get a valley-shaped of optical transmission against voltage.

Broadband multiple-cascaded integration of electroabsorption modulators and high impedance transmission lines by lowering standing-wave effect.

Standing wave effect of applied electrical field on optical modulation in multiple-cascaded integration (CI) electroabsorption modulator (EAM) and high-impedance transmission line (HITL) has been investigated in this paper. As modulation frequency is increased to the scale that electrical wavelength is in the order of optical modulator length, multiple electrical reflection and self-interference on impedance-mismatch boundaries becomes significant, leading to strong position-dependent field distribution and degrading modulation bandwidth. Sharp bandwidth roll of electrical-optical (EO) conversion by standing wave has been found experimentally in CI structure, consistent with simulation results.

Bioaccumulation and toxicodynamics of cadmium to freshwater planarian and the protective effect of N-acetylcysteine.

Although toxic responses of freshwater planarians after exposure to environmental toxicants can be observed through external toxicological end points, physiological responses inside the bodies of treated planarians have rarely been investigated. The present study was designed, using cadmium (Cd) as a reference toxicant, to determine its bioaccumulation and toxicodynamics in the freshwater planarian, Dugesia japonica, after acute toxicity was obtained. Accumulated Cd concentrations, metallothionein levels, and the oxidative status in planarians were determined after exposure to Cd.

Alterations of biochemical parameters in malformed Indian rice frogs, Rana limnocharis from Southern Taiwan.

The purpose of this study is to investigate the factors that cause malformed frogs in upstream Kaoping river (KP site) and Tungkang river (T site) of Southern Taiwan. In this experiment, the activities of monooxygenase (MO), glutathione-S-transferase (GST), acetylcholinesterase (AchE) as well as the concentration of vitellogenin (Vg) in the liver were measured. Results show that activities of MO, GST and AchE, and Vg levels in normal frogs (male/female) were 0.

In vivo and in vitro metabolism of tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), by the freshwater planarian, Dugesia japonica.

Cigarette smoke is a risk factor for human health, and many studies were conducted to investigate its adverse effects on humans and other mammals. However, since large amounts of cigarette products are produced and consumed, it is possible that tobacco chemicals can end up in aquatic environments through several routes, thus influencing aquatic organisms. In this study, the presence of tobacco-specific nitrosamine (TSNA), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), in aquatic environment was demonstrated.

Field-driven all-optical wavelength converter using novel InGaAsP/InAlGaAs quantum wells.

A new type of semiconductor quantum well (QW) for high-speed all optical wavelength converter (AOWC) is proposed and demonstrated in this work. Based on InGaAsP (well)/InGaAlAs (barrier) multiple QW, large electron band offset ratio relative to heavy hole can be attained to shorten sweep rate of photocarrier driven by electric field, realizing high-speed efficient AOWC through cross absorption modulation (XAM). By such QWs, an optical waveguide with high-speed electrode connection is fabricated.

The preferential accumulation of cadmium in the head portion of the freshwater planarian, Dugesia japonica (Platyhelminthes: Turbellaria).

Free-living freshwater planarians are considered to have the potential for development as an experimental model for toxicological studies on xenobiotics, including metals. However, little was known about the distribution patterns of metals in the body of treated planarians. This study was conducted to determine the tissue distribution patterns of cadmium (Cd) in different body portions of the treated planarian, Dugesia japonica.

Comparative tissue distributions of cadmium chloride and cadmium-based quantum dot 705 in mice: Safety implications and applications.

Cadmium (Cd) is a component in quantum dot 705 (QD705). Whether QD705 behaves similar to Cd in vivo is of great concern. We compared the distributional kinetics of cadmium chloride (CdCl(2)) and QD705 in mice after intravenous injection.

Novel ultra-wideband (UWB) photonic generation through photodetection and cross-absorption modulation in a single electroabsorption modulator.

We propose and demonstrate, by proof of concept, a novel method of ultra-wide band (UWB) photonic generation using photodetection and cross-absorption modulation (XAM) of multiple quantum wells (MQW) in a single short-terminated electroabsorption modulator (SEAM). As an optical pump pulse excite the MQWs of SEAM waveguide, the probe light pulse with the same polarity can be generated through XAM, simultaneously creating photocurrent pulse propagating along the waveguide. Using the short termination of SEAM accompanied by the delayed microwave line, the photocurrent pulse can be reversed in polarity and re-modulated the waveguide, forming a monocycle UWB optical pulse.

Involvement of oxidative stress and activation of aryl hydrocarbon receptor in elevation of CYP1A1 expression and activity in lung cells and tissues by arsenic: an in vitro and in vivo study.

Epidemiological evidence indicated that there was a synergistic interaction between arsenic and cigarette smoke on enhancement of lung cancer risk. Benzo[a]pyrene (B[a]P), a component in cigarette smoke, is one of the most carcinogenic compounds known. Animal studies have demonstrated that there were increased benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE) adduct formation and lung tumorigenesis in animals when they were coexposed to B[a]P and arsenic.

Histopathological and biochemical evidence of hepatopancreatic toxicity caused by cadmium and zinc in the white shrimp, Litopenaeus vannamei.

The white shrimp, Litopenaeus vannamei, a globally important cultured prawn species, is an ideal animal for studying the impairment caused by the effects of heavy metals that are often detected in coastal areas. In this study, L. vannamei was exposed to different concentrations of cadmium (Cd) and zinc (Zn) for up to 28 d.

Computational and ultrastructural toxicology of a nanoparticle, Quantum Dot 705, in mice.

We conducted pharmacokinetic and toxicology studies on Quantum Dot 705 (QD705) in male ICR mice for up to 6 months after a single intravenous dose. Time-course sacrifices were carried out at 1, 4, and 24 h; 3, 7, 14, and 28 days; and 6 months on groups of six mice per time point. Mass balance studies were also carried out at 24 h, 28 days, and 6 months.

Enhancements of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) metabolism and carcinogenic risk via NNK/arsenic interaction.

Epidemiological studies indicated an enhancement of cigarette smoke-induced carcinogenicity, including hepatocellular carcinoma, by arsenic. We believe that arsenic will enhance the expression of hepatic CYP2A enzyme and NNK metabolism (a cigarette smoke component), thus its metabolites, and carcinogenic DNA adducts. Male ICR mice were exposed to NNK (0.

Persistent tissue kinetics and redistribution of nanoparticles, quantum dot 705, in mice: ICP-MS quantitative assessment.

Background: Quantum dots (QDs) are autofluorescent semiconductor nanocrystals that can be used for in vivo biomedical imaging. However, we know little about their in vivo disposition and health consequences.

Objectives: We assessed the tissue disposition and pharmacokinetics of QD705 in mice.

Reproduction obstacles for the female green neon shrimp (Neocaridina denticulata) after exposure to chlordane and lindane.

The purpose of this study was to investigate the effects of chlordane and lindane on reproduction obstacles and endocrine disruption in female green neon shrimp (Neocaridina denticulata). Individuals of N. denticulata, a common inhabitant of freshwater systems in Taiwan, was exposed to different levels of chlordane (1 and 10 ngl(-1)) and lindane (0.

Metallothionein induction and heavy metal accumulation in white shrimp Litopenaeus vannamei exposed to cadmium and zinc.

Metallothioneins (MTs) have been widely considered for their potential use as specific biomarkers to reflect the existence of heavy metal pollution, because their induction has been observed to be obviously elevated after heavy metal exposure in a large number organism studied. However, relatively fewer efforts have been made in MT-related studies of prawn species, such as the white shrimp Litopenaeus vannamei, a globally important aquaculture species. With the results from gel filtration chromatography, we demonstrate the existence of MTs or MT-like proteins in L.

Effects of cadmium and zinc on oxygen consumption, ammonium excretion, and osmoregulation of white shrimp (Litopenaeus vannamei).

White shrimp, Litopenaeus vannamei, a globally important cultured prawn species, is an ideal animal for studying the impairment caused by the effects of heavy metals that are often detected in coastal areas. The main purpose of the present study was to detect the acute toxicity of Cd and Zn to L. vannamei, and to investigate their effects on gill functions, which have not been carried out in this species before, hoping to obtain some important significance.