Leah Grossman

Characterization of behavioral and endocrine effects of LSD on zebrafish

Lysergic acid diethylamide (LSD) is a potent hallucinogenic drug that strongly affects animal and human behavior. Although adult zebrafish (Danio rerio) are emerging as a promising neurobehavioral model, the effects of LSD on zebrafish have not been investigated previously. Several behavioral paradigms (the novel tank, observation cylinder, light-dark box, open field, T-maze, social preference and shoaling tests), as well as modern video-tracking tools and whole-body cortisol assay were used to characterize the effects of acute LSD in zebrafish. While lower doses (5-100 microg/L) did not affect zebrafish behavior, 250 microg/L LSD increased top dwelling and reduced freezing in the novel tank and observation cylinder tests, also affecting spatiotemporal patterns of activity (as assessed by 3D reconstruction of zebrafish traces and ethograms). LSD evoked mild thigmotaxis in the open field test, increased light behavior in the light-dark test, reduced the number of arm entries and freezing in the T-maze and social preference test, without affecting social preference. In contrast, LSD affected zebrafish shoaling (increasing the inter-fish distance in a group), and elevated whole-body cortisol levels. Overall, our findings show sensitivity of zebrafish to LSD action, and support the use of zebrafish models to study hallucinogenic drugs of abuse.

Modeling seizure-related behavioral and endocrine phenotypes in adult zebrafish

Larval zebrafish (Danio rerio) have recently been suggested as a high-throughput experimental model of epilepsy-related pathogenetic states. Here we use adult zebrafish to study behavioral symptoms associated with drug-evoked seizures. Experimental epilepsy-like states were evoked in zebrafish by exposure for 20min to three chemoconvulsant drugs: caffeine (250mg/L; 1.3mM), pentylenetetrazole (1.5g/L; 11.0mM) and picrotoxin (100mg/L; 0.17mM). Fish behavior was analyzed using manual and video-tracking methods (Noldus Ethovision XT7). Compared to their respective controls, all three drug-treated groups showed robust seizure-like responses (hyperactivity bouts, spasms, circular and corkscrew swimming) accompanied by elevated whole-body cortisol levels (assessed by ELISA). In contrast, control fish did not display seizure-like behaviors and had significantly lower cortisol levels. Paralleling behavioral and endocrine phenotypes observed in clinical and rodent studies, our data implicates adult zebrafish as an emerging experimental model for epilepsy research.

Behavioral and physiological effects of RDX on adult zebrafish

1,3,5-Trinitroperhydro-1,3,5-triazine (RDX) is a nitroamine explosive, with common toxic effects including seizures. Here, we explore the behavioral effects of acute RDX exposure in adult zebrafish Danio rerio, a rapidly developing model in neuroscience and neurotoxicology research. Overall, a 30-min exposure to RDX low dose of 0.1 mM evoked behavioral activation in zebrafish, while a higher dose of 1 mM markedly reduced exploration, increased freezing and evoked seizure-like responses (i.e., bouts of hyperactivity, spasms, and corkscrew swimming). Likewise, whole-body cortisol levels were also significantly elevated in fish exposed to 1 mM (but not 0.1 mM) RDX. In line with clinical and animal data, our study demonstrates the dose-dependent behavioral activation and pro-convulsant effects of RDX in zebrafish-based models.

Underutilization of Partial Nephrectomy for Stage T1 Renal Cell Carcinoma in the United States, Trends From 2000 to 2008. A Long Way to Go

INTRODUCTION Recent American Urologic Association Guidelines for small renal masses recommend partial nephrectomy for surgical treatment of T1 renal masses to preserve renal function and minimize cardiovascular comorbidities. This procedure is performed more often than in the past, after the technical issues of hemorrhage, fistula, and technique evolved. We reviewed the trends, practice patterns, and application of partial nephrectomy for T1 renal cell carcinoma in the United States from 2000 to 2008, before the American Urologic Association Guidelines. The objective is to investigate whether economic or societal factors favor the use of partial over radical nephrectomy surgery. METHODS Data on 142,194 cases from 1267 hospitals diagnosed with kidney and renal pelvis cancer in the National Cancer DataBase from 2000 to 2008 were the basis of the study. RESULTS Partial nephrectomy rates for stage T1 kidney and renal pelvis cancer have increased from 17% in 2000 to 31% in 2008. Differences in partial nephrectomy rates that arise from sex or race were not large. However, there was a disproportionate increase based on income and education. Also, there were differences based on insurance status; patients with managed care, in the military and veterans had higher partial nephrectomy rates. Partial nephrectomy rates were higher in teaching and research hospitals and in veterans hospitals. Geographically, the procedure was performed at higher rates in the eastern and midwestern parts of the country. CONCLUSIONS Partial nephrectomy rates for stage T1 renal cell carcinoma increased from 17% in 2000 to 31% in 2008. The procedure has been used preferentially with patients who are more educated and have high incomes.

Aquatic toxicology of fluoxetine: understanding the knowns and the unknowns.

Fluoxetine is one of the most prescribed psychotropic medications, and is an agent of increasing interest for environmental toxicology. Fish and other aquatic organisms are excellent models to study neuroactive small molecules like fluoxetine. However, prone to variance due to experimental factors, data obtained in these models need to be interpreted with caution, using proper experimental protocols, study designs, validated endpoints as well as well-established models and tests. Choosing the treatment protocol and dose range for fluoxetine and other serotonergic drugs is critical for obtaining valid test results and correct data interpretation. Here we discuss the value of aquatic models to study fluoxetine effects, based on prior high-quality research, and outline the directions of future translational studies in the field. We review fluoxetine-evoked phenotypes in acute vs. chronic protocols, discussing them in the contact of complex role of serotonin in behavioral regulation. We conclude that zebrafish and other aquatic models represent a useful in-vivo tool for fluoxetine pharmacology and (eco)toxicology research.

Anxiogenic-like effects of chronic nicotine exposure in zebrafish

Nicotine is one of the most widely used and abused legal drugs. Although its pharmacological profile has been extensively investigated in humans and rodents, nicotine CNS action remains poorly understood. The importance of finding evolutionarily conserved signaling pathways, and the need to apply high-throughput in vivo screens for CNS drug discovery, necessitate novel efficient experimental models for nicotine research. Zebrafish (Danio rerio) are rapidly emerging as an excellent organism for studying drug abuse, neuropharmacology and toxicology and have recently been applied to testing nicotine. Anxiolytic, rewarding and memory-modulating effects of acute nicotine treatment in zebrafish are consistently reported in the literature. However, while nicotine abuse is more relevant to long-term exposure models, little is known about chronic effects of nicotine on zebrafish behavior. In the present study, chronic 4-day exposure to 1-2mg/L nicotine mildly increased adult zebrafish shoaling but did not alter baseline cortisol levels. We also found that chronic exposure to nicotine evokes robust anxiogenic behavioral responses in zebrafish tested in the novel tank test paradigm. Generally paralleling clinical and rodent data on anxiogenic effects of chronic nicotine, our study supports the developing utility of zebrafish for nicotine research.

First Prize: Isoprostane: Quantitation of Renal Ischemia and Reperfusion Injury After Renal Artery Clamping in an Animal Model

BACKGROUND AND PURPOSE Laparoscopic and robotic partial nephrectomy involves temporary clamping of the renal artery, making the kidney susceptible to ischemic damage. Isoprostane represents one potential marker of oxidative injury. The objective was to determine if renal interstitial isoprostane levels can quantitate renal damage secondary to warm ischemia. A second goal is to investigate allopurinol for renoprotective abilities using this model. We chose to investigate potential renoprotection of allopurinol because previous studies have demonstrated transplant kidneys pretreated with allopurinol to have less damage from ischemia. MATERIALS AND METHODS A microdialysis probe was inserted into the renal parenchyma of rats to allow continuous dialysis and collection of the effluent for isoprostane levels. After clamping of the renal vessels for predefined intervals of ischemia, the interstitial effluent from the probe was collected and subsequently analyzed for isoprostane levels with and without allopurinol pretreatment. RESULTS Clamping of the renal artery and vein produced increases in isoprostane levels during the ischemic period and larger increases during reperfusion. There was a trend for increased postclamp isoprostane levels as clamp times increased. When comparing isoprostane levels in rats that did not receive allopurinol, there were significant differences between the clamp and postclamp levels of isoprostane, with allopurinol offering protection to the kidney from ischemic changes caused by clamping the renal hilum. CONCLUSIONS Our data have demonstrated that isoprostane levels are a potential real-time marker of renal ischemia and reperfusion injury. We also found allopurinol administration demonstrated a trend toward renoprotective abilities in the hilar occluded kidney.

Phenotyping of Zebrafish Homebase Behaviors in Novelty-Based Tests

Various novelty-based assays used to quantify zebrafish (Danio rerio) behavior show a striking similarity to behavioral responses in rodents. Exposed to the open field test, zebrafish establish overt homebases demonstrating clear preference for a particular area of the tank. This behavior aims to establish a “safe zone” that zebrafish can familiarize themselves with and feel secure in, and is similar to homebase behaviors of various laboratory rodent species. Here we outline a simple protocol for homebase phenotyping

Retrograde Renal Cooling to Minimize Ischemia

OBJECTIVE During partial nephrectomy, renal hypothermia has been shown to decrease ischemia induced renal damage which occurs from renal hilar clamping. In this study we investigate the infusion rate required to safely cool the entire renal unit in a porcine model using retrograde irrigation of iced saline via dual-lumen ureteral catheter. MATERIALS AND METHODS Renal cortical, renal medullary, bowel and rectal temperatures during retrograde cooling in a laparoscopic porcine model were monitored in six renal units. Iced normal saline was infused at 300 cc/hour, 600 cc/hour, 1000 cc/hour and gravity (800 cc/hour) for 600 seconds with and without hilar clamping. RESULTS Retrograde cooling with hilar clamping provided rapid medullary renal cooling and significant hypothermia of the medulla and cortex at infusion rates ≥ 600 cc/hour. With hilar clamping, cortical temperatures decreased at -0.90 C/min. reaching a threshold temperature of 26.90 C, and medullary temperatures decreased at -0.90 C/min. reaching a temperature of 26.10 C over 600 seconds on average for combined data at infusion rates = 600 cc/hour. The lowest renal temperatures were achieved with gravity infusion. Without renal hilum clamping, retrograde cooling was minimal at all infusion rates. CONCLUSIONS Significant renal cooling by gravity infusion of iced cold saline via a duel lumen catheter with a clamped renal hilum was achieved in a porcine model. Continuous retrograde irrigation with iced saline via a two way ureteral catheter may be an effective method to induce renal hypothermia in patients undergoing robotic assisted and/or laparoscopic partial nephrectomy.