Food memory circuits regulate eating and energy balance.

In mammals, learning circuits play an essential role in energy balance by creating associations between sensory cues and the rewarding qualities of food. This process is altered by diet-induced obesity, but the causes and mechanisms are poorly understood. Here, we exploited the relative simplicity and wealth of knowledge about the D. melanogaster reinforcement learning network, the mushroom body, in order to study the relationship between the dietary environment, dopamine-induced plasticity, and food associations. We show flies that are fed a high-sugar diet cannot make associations between sensory cues and the rewarding properties of sugar. This deficit was caused by diet exposure, not fat accumulation, and specifically by lower dopamine-induced plasticity onto mushroom body output neurons (MBONs) during learning. Importantly, food memories dynamically tune the output of MBONs during eating, which instead remains fixed in sugar-diet animals. Interestingly, manipulating the activity of MBONs influenced eating and fat mass, depending on the diet. Altogether, this work advances our fundamental understanding of the mechanisms, causes, and consequences of the dietary environment on reinforcement learning and ingestive behavior.

Blockade of the endovanilloid receptor, TRPV1, and of the endocannabinoid enzyme, FAAH, within the nucleus accumbens shell elicits anxiolytic-like effects in male rats.

RATIONALE: The functional role of the endocannabinoid system (ECS) and Transient Receptor Potential Vanilloid type-1 (TRPV1) within the Nucleus Accumbens shell (NAc shell) remains unknown. Preclinical studies in rodents have reported that the ECS modulates emotional responses such as anxiety. The NAc shell has a high density of synaptically co-localized cannabinoid receptor type-1 (CB1R) and TRPV1, suggesting a potential involvement in the modulation of anxiety. OBJECTIVES: The present study aims to establish the role of ECS-TRPV1 interactions within the NAc shell and its effects on anxiety. It is hypothesized that the neurochemical regulation elicited by ECS within the NAc shell mediates anxiety-like behaviors in rodents. METHODS: In this study, male Sprague Dawley rats were implanted with bilateral brain cannula targeting the NAc shell. Following recovery from surgery, animals received microinfusion pretreatments (0, 0.125, 0.5 nmol/0.4 µl) of N-arachidonoyl-serotonin (AA-5-HT), a dual blocker of the endocannabinoid-inactivating enzyme, fatty acid amide hydrolase (FAAH) and a TRPV1 antagonist in the NAc shell. Following treatment, animals were tested in an elevated plus maze (EPM) paradigm for a period of 5 minutes. At the end of the experiment, animals were sacrificed and their brains collected for histological and biochemical analysis. RESULTS: Results showed that animals treated with AA-5-HT in a dose dependent manner spent significantly more time in the open arms than vehicle-treated animals. In addition, AA-5-HT administration induced a significant downregulation of CB1R expression in the NAc shell. CONCLUSIONS: The present findings suggest that the ECS within the NAc shell modulates anxiety-like behaviors via FAAH and CB1R activity.

Application of electrocoagulation for the efficient pollutants removal to reuse the treated wastewater in the dyeing process of the textile industry.

The possibility of using electrocoagulation for efficient removal of pollutants in the industrial liquid waste of a textile industry was studied. The performance of the process was evaluated through the analysis of color, turbidity, and chemical oxygen demand (COD). The analysis was first done with the wastewater coming from the process of dyeing linen, which is the most polluting of all effluents that reach the residual effluent pool (REP). For the analysis, the MODDE 7.0 software was used to construct a statistical model. With the results obtained from this model and the experimental measurements, response surfaces were obtained. These response surfaces predicted the behavior of electrocoagulation for different values of the studied variables (pH, current density, and treatment time). Based on the obtained results, the wastewater coming from the REP was treated using the optimum values for the operational variables. After the treatment it was possible to remove 86% color, 82% turbidity, and 59% COD. It was demonstrated that reusing the treated water in the process of wool dyeing does not have a negative effect on the quality of the dyed fabric. Thus, it is possible to implement the process in the textile industry to reduce the consumption of water.

Ventral Pallidum Is the Primary Target for Accumbens D1 Projections Driving Cocaine Seeking.

Outputs from the nucleus accumbens (NAc) include projections to the ventral pallidum and the ventral tegmental area and subtantia nigra in the ventral mesencephalon. The medium spiny neurons (MSN) that give rise to these pathways are GABAergic and consist of two populations of equal number that are segregated by differentially expressed proteins, including D1- and D2-dopamine receptors. Afferents to the ventral pallidum arise from both D1- and D2-MSNs, whereas the ventral mesencephalon is selectively innervated by D1-MSN. To determine the extent of collateralization of D1-MSN to these axon terminal fields we used retrograde labeling in transgenic mice expressing tdTomato selectively in D1-MSN, and found that a large majority of D1-MSN in either the shell or core subcompartments of the accumbens collateralized to both output structures. Approximately 70% of D1-MSNs projecting to the ventral pallidum collateralized to the ventral mesencephalon, whereas >90% of mesencephalic D1-MSN afferents collateralized to the ventral pallidum. In contrast, <10% of dorsal striatal D1-MSNs collateralized to both the globus pallidus and ventral mesencephalon. D1-MSN activation is required for conditioned cues to induce cocaine seeking. To determine which D1-MSN projection mediates cued cocaine seeking, we selectively transfected D1-MSNs in transgenic rats with an inhibitory Gi-coupled DREADD. Activation of the transfected Gi-DREADD with clozapine-N-oxide administered into the ventral pallidum, but not into the ventral mesencephalon, blocked cue-induced cocaine seeking. These data show that, although accumbens D1-MSNs largely collateralize to both the ventral pallidum and ventral mesencephalon, only D1-MSN innervation of the ventral pallidum is necessary for cue-induced cocaine seeking.SIGNIFICANCE STATEMENT Activity in D1 dopamine receptor-expressing neurons in the NAc is required for rodents to respond to cocaine-conditioned cues and relapse to drug seeking behaviors. The D1-expressing neurons project to both the ventral pallidum and ventral mesencephalon, and we found that a majority of the neurons that innervate the ventral pallidum also collateralize to the ventral mesencephalon. However, despite innervating both structures, only D1 innervation of the ventral pallidum mediates cue-induced cocaine seeking.

Dorsal Cochlear Nucleus Fusiform-cell Plasticity is Altered in Salicylate-induced Tinnitus.

Following noise overexposure and tinnitus-induction, fusiform cells of the dorsal cochlear nucleus (DCN) show increased spontaneous firing rates (SFR), increased spontaneous synchrony and altered stimulus-timing-dependent plasticity (StDP), which correlate with behavioral measures of tinnitus. Sodium salicylate, the active ingredient in aspirin, which is commonly used to induce tinnitus, increases SFR and activates NMDA receptors in the ascending auditory pathway. NMDA receptor activation is required for StDP in many brain regions, including the DCN. Blocking NMDA receptors can alter StDP timing rules and decrease synchrony in DCN fusiform cells. Thus, systemic activation of NMDA receptors with sodium salicylate should elicit pathological changes to StDP, thereby increasing SFR and synchrony and induce tinnitus. Herein, we examined the action of salicylate in tinnitus generation in guinea pigs in vivo by measuring tinnitus using two behavioral measures and recording single-unit responses from DCN fusiform cells pre- and post-salicylate administration in the same animals. First, we show that animals administered salicylate show evidence of tinnitus using both behavioral paradigms, cross-validating the tests. Second, fusiform cells in animals with tinnitus showed increased SFR, synchrony and altered StDP timing rules, like animals with noise-induced tinnitus. These findings suggest that alterations to fusiform-cell plasticity are an essential component of tinnitus, regardless of induction technique.

Regio-specific hydroxylation of nonylphenol and the involvement of CYP2K- and CYP2M-like iso-enzymes in Atlantic salmon (Salmo salar).

Previously, it has been demonstrated that nonylphenol (NP) has a dual function in regulating reproductive hormones by: (1) increasing the activity of steroid metabolizing enzymes at low concentration, that does not induce vitellogenin (Vtg) and zona radiata proteins and (2) decreasing the activity of these enzymes at higher concentration [Environ. Health Perspect. 105 (1997) 109; Environ. Toxicol Chem. 16 (1997) 2576]. To more precisely understand the estrogenic effects of NP in fish and a possible interference with steroid hormone metabolism, we investigated in the Atlantic salmon the identity of the cytochrome P450 enzymes involved in NP hydroxylation. Up to 9 metabolites were separated by radio-HPLC when [R-(14)C]-4n-NP was incubated with hepatic microsomes from juvenile salmon. In control fish the major metabolites were identified as monohydroxylated products at omega-, (omega-1)- and (omega-2)-positions of the alkyl chain of 4n-NP. Salmon hepatic microsomes formed omega-, (omega-1)- and (omega-2)-lauric acid (LA) hydroxylation products. The potency of alpha-naphthoflavone, ketoconazole and ethynylestradiol (non-specific, but strong inhibitors of CYP1A, 2K and 3A, respectively) on LA and NP hydroxylations were assessed in the present study. Ketoconazole inhibited omega-, (omega-1)- and (omega-2)-hydroxylations of LA and 4n-NP and was the only inhibitor of omega-hydroxylation of both substrates. Ethynylestradiol specifically inhibited (omega-1)- and (omega-2)-hydroxylations of LA as well as 4n-NP. Interestingly, the lowest NP dose (1 mg/kg) was the most potent inducer of NP-metabolites formation. These results suggest the involvement of CYP2M- and 2K-like enzymes in terminal and subterminal hydroxylations of 4n-NP respectively, and was confirmed by the competitive inhibition between LA and 4n-NP. The production of one unidentified 4n-NP metabolite was not affected by any of the chemicals used, suggesting a possible ring hydroxylation with involvement of another cytochrome P450 isoform. Our data reveal a novel aspect of CYP isozymes involvement in NP metabolism that may complicate the assessment of its endocrine effects. Hence, the regio-selective hydroxylation of endocrine disruptors, such as NP, by CYP isozymes is revealed as a possible new marker of estrogenicity.

In vivo and in vitro metabolism and organ distribution of nonylphenol in Atlantic salmon (Salmo salar).

In the environment, nonylphenol (NP) occurs predominantly as a degradation product of nonylphenol ethoxylate (NPE). They can be found in many types of products including detergents, plastics, emulsifiers, pesticides, and industrial and consumer cleaning products. As a consequence of their use in a variety of products, they are quite common in rivers and other aquatic environments that receive sewage discharges. Because of its enhanced resistance towards biodegradation, toxicity, estrogenic effects, and ability to bioaccumulate in aquatic organisms NP has been regarded as the most critical metabolite of APEs. We have studied the in vivo and in vitro metabolism and organ distribution of NP in juvenile salmon. Fish were exposed in vivo to waterborne [3H]-4-n-NP for a period up to 72 h or were administered a single oral dose of [3H]-4-n-NP. In vitro biotransformation of NP was studied by exposure of cultured salmon hepatocytes to [3H]-4-n-NP in the presence or absence of a CYP1A-inducer, beta-naphthoflavone (betaNF). Our results show that 4-n-NP was mainly metabolized in vivo, to its corresponding glucuronide conjugates and hydroxylates. The major route of excretion was the bile. The half-life of residues in carcass and muscle was between 24 and 48 h in both waterborne and dietary exposure. In whole body autoradiography, intragastric administered [3H]-4-n-NP was mainly present in the gastrointestinal tract and bile. NP-derived radioactivity in fish exposed via water was more evenly distributed in the organs compared to intragastric exposure and were observed in the intestinal contents, liver, kidney, gills, skin, abdominal fat and brain. In vitro pretreatment of hepatocytes with betaNF had no effect on rates or patterns of NP biotransformation. The in vitro metabolic rate of NP were 118 pmol NP metabolized/h/0.5x10(6) cells without betaNF, and 98 pmol NP metabolized/h/0.5x10(6) cells when betaNF was added to the culture medium.

Metabolism and organ distribution of nonylphenol in Atlantic salmon (Salmo salar).

Nonylphenol (NP) is a breakdown product of alkylphenol polyethoxylates (APEs), an important class of non-ionic surfactants that are widely used in many detergent formulations and plastic products for industrial and domestic use. A complex microbial degradation pattern, characterized by the formation of several metabolic products that are more toxic than the parent compound, has been established for APEs. We have studied the in vivo metabolism and organ distribution of NP in juvenile salmon. Fish were exposed to a single oral dose of [3H]-4-n-NP (1295 KBq, 25 micrograms) and sampled at 24, 48 and 72 h after exposure. Metabolites were separated by radio-high-performance liquid chromatography and tentatively identified by cochromatography with standards characterized by mass spectrometry. Our results show that 4-n-NP was mainly metabolized in vivo to its corresponding glucuronide conjugate and to a lesser extent to various hydroxylated and oxidated compounds. Biliary excretion at 72 h after dosing amounted to 2.83 +/- 0.75% of the administered radioactivity. Kinetic analysis shows that NP-glucuronide accounted for 83, 95 and 81% of total radioactivity in the HPLC-injected bile sample at 24, 48 and 72 h, respectively, after exposure. The half-life of residues in carcass and muscle was between 24 and 48 h after exposure.

Urinary metabolites of 4-n-nonylphenol in rainbow trout (Oncorhynchus mykiss).

Nonylphenol is present in surface water and aquatic sediments and because of its lipophilic characteristics shows a considerable potential to bioaccumulate in aquatic organisms. Nonylphenol inhibits testicular growth and induces vitellogenin synthesis in male rainbow trout. In order to better understand the effects of nonylphenol on fish and its impact in the aquatic environment, it is essential to elucidate the metabolic fate of this compound. A single oral dose (5 mg, 1850 KBq) of [3H]4-n-nonylphenol resulted in 1.1% and 3.0% of the ingested radioactivity eliminated in urine after 24 and 48 h, respectively. Four metabolites were separated by radio-HPLC and tentatively identified by mass spectrometry. Urinary metabolites likely resulted from the initial omega-oxidation of 4-n-nonylphenol to the putative 9-(4-hydroxyphenyl)-nonanoic acid which subsequent beta-oxidation led to 4-hydroxybenzoic acid as major metabolite. Intermediary metabolites, namely 3-(4-hydroxyphenyl) propionic acid and 3-(4-hydroxyphenyl)-2-propenoic acid confirmed the occurrence of this beta-oxidative pathway. Urinary metabolites identified in this study were quite different from biotransformation products previously described in bile of trout treated with 4-n-nonylphenol.

Characterization of biliary metabolites of 4-n-nonylphenol in rainbow trout (Oncorhynchus mykiss).

1. [R-2,6-3H]-4-n-nonylphenol was synthesized and a single dose (5 mg, 1850 KBq) orally administered to rainbow trout. After 48 h, the radioactivity present in the bile amounted 5.5%. More than ten biliary metabolites were separated by hplc and collected for subsequent mass spectrometry analysis. The metabolic profile was totally modified by beta-glucuronidase hydrolysis, showing that most of the metabolites were glucuronic acid conjugates. 2. Conjugated metabolites were identified by lc-ms analysis and their aglycones were analysed by gc-ms analysis as TMS and acetyl derivatives. 3. The major metabolite accounted for 52+/-11% of the biliary radioactivity and was identified as nonylphenol-glucuronide. 4. Nonylphenol was hydroxylated at both omega and omega-1 positions of the alkyl chain, giving 9-hydroxynonylphenol and 8-hydroxynonylphenol. 5. 9-Hydroxynonylphenol was oxidized to the corresponding acid, and subsequently beta-oxidized, yielding 7-(4-hydroxyphenyl)heptanoic acid, 5-(4-hydroxyphenyl)pentanoic acid, 3-(4-hydroxyphenyl)propionic acid and 3-(4-hydroxyphenyl)-2-propenoic acid.

Revision of total hip arthroplasty using the R.M. isoelastic prosthesis.

A cemented revision of failed total hip arthroplasty is prone to early mechanical failure. Cementless revision seems to be much more promising. We present our 2 year follow-up of 19 cementless revisions using the R.M. isoelastic stem. During follow-up special attention focused on the restoration of bone stock on the femoral side of the arthroplasty. Bone stock deficiencies encountered during the operation were managed with grafts. Other complications to solve during the procedure were encountered frequently. The average follow-up was 58 months. Rating the results following Merle d'Aubigné and Postel showed very good or good result only in half of the cases, one case needed a revision. Nevertheless good restoration of bone stock was observed in nearly all cases. A greater number of patients should be followed for a longer period of time to establish the exact role of this prosthesis design.

Surgical treatment of spinal metastases.

Between 1985 and 1991, thirty-one patients with spinal metastases were operated in our department. The aim of the surgical treatment is to abolish pain and instability caused by neurological involvement and bony invasion. Anterior decompression with fixation by means of a methylmethacrylate cement block was used. In some cases additional posterior fixation was used in a second procedure. Pain was reduced in 78% of the patients, and 70% underwent improvement of their neurological status. The quality of life was improved, but the short survival confirms the palliative nature of this kind of surgery.