An Animal Model of Alcohol Dependence to Screen Medications for Treating Alcoholism.

Despite the high prevalence of alcohol use disorders in the United States, only a relatively small percentage of those afflicted seek treatment. This is further compounded by the fact that there are too few medications available to effectively treat this significant public health problem. The need for identifying and evaluating more effective treatments that aid in preventing relapse and/or tempering risky and harmful alcohol consumption cannot be overstated. Use of animal models represents a critical step in the process of screening, identifying, and informing plans for prioritizing the most promising candidate medications that can be advanced to the next stage of evaluation (clinical laboratory paradigms and controlled clinical trials). Numerous animal models have been developed to study excessive levels of alcohol self-administration. In recent years, a large literature has amassed of studies in which rodent models of dependence have been linked with alcohol self-administration procedures. This chapter focuses on studies employing a dependence model that involves chronic exposure to alcohol vapor by inhalation, which yields in both mice and rats significant escalation of voluntary alcohol consumption. These animal models of dependence and alcohol self-administration have revealed valuable insights about underlying mechanisms that drive excessive drinking. Additionally, this preclinical approach is useful in evaluating the effects of medications on escalated drinking associated with dependence vs more stable levels displayed by nondependent animals.

The glucagon-like peptide-1 receptor as a potential treatment target in alcohol use disorder: evidence from human genetic association studies and a mouse model of alcohol dependence.

The hormone glucagon-like peptide-1 (GLP-1) regulates appetite and food intake. GLP-1 receptor (GLP-1R) activation also attenuates the reinforcing properties of alcohol in rodents. The present translational study is based on four human genetic association studies and one preclinical study providing data that support the hypothesis that GLP-1R may have a role in the pathophysiology of alcohol use disorder (AUD). Case-control analysis (N = 908) was performed on a sample of individuals enrolled in the National Institute on Alcohol Abuse and Alcoholism (NIAAA) intramural research program. The Study of Addiction: Genetics and Environment (SAGE) sample (N = 3803) was used for confirmation purposes. Post hoc analyses were carried out on data from a human laboratory study of intravenous alcohol self-administration (IV-ASA; N = 81) in social drinkers and from a functional magnetic resonance imaging study in alcohol-dependent individuals (N = 22) subjected to a Monetary Incentive Delay task. In the preclinical study, a GLP-1R agonist was evaluated in a mouse model of alcohol dependence to demonstrate the role of GLP-1R for alcohol consumption. The previously reported functional allele 168Ser (rs6923761) was nominally associated with AUD (P = 0.004) in the NIAAA sample, which was partially replicated in males of the SAGE sample (P = 0.033). The 168 Ser/Ser genotype was further associated with increased alcohol administration and breath alcohol measures in the IV-ASA experiment and with higher BOLD response in the right globus pallidus when receiving notification of outcome for high monetary reward. Finally, GLP-1R agonism significantly reduced alcohol consumption in a mouse model of alcohol dependence. These convergent findings suggest that the GLP-1R may be an attractive target for personalized pharmacotherapy treatment of AUD.

Repeated episodes of chronic intermittent ethanol promote insensitivity to devaluation of the reinforcing effect of ethanol.

Studies in animal models have shown that repeated episodes of alcohol dependence and withdrawal promote escalation of drinking that is presumably associated with alterations in the addiction neurocircuitry. Using a lithium chloride-ethanol pairing procedure to devalue the reinforcing properties of ethanol, the present study determined whether multiple cycles of chronic intermittent ethanol (CIE) exposure by vapor inhalation also alters the sensitivity of drinking behavior to the devaluation of ethanol's reinforcing effects. The effect of devaluation on operant ethanol self-administration and extinction was examined in mice prior to initiation of CIE (short drinking history) and after repeated cycles of CIE or air control exposure (long drinking history). Devaluation significantly attenuated the recovery of baseline ethanol self-administration when tested either prior to CIE or in the air-exposed controls that had experienced repeated bouts of drinking but no CIE. In contrast, in mice that had undergone repeated cycles of CIE exposure that promoted escalation of ethanol drinking, self-administration was completely resistant to the effect of devaluation. Devaluation had no effect on the time course of extinction training in either pre-CIE or post-CIE mice. Taken together, these results are consistent with the suggestion that repeated cycles of ethanol dependence and withdrawal produce escalation of ethanol self-administration that is associated with a change in sensitivity to devaluation of the reinforcing properties of ethanol.

Contrast-induced acute kidney injury after computed tomography prior to transcatheter aortic valve implantation.

AIM: To identify independent predictors of contrast medium-induced acute kidney injury (CI-AKI) after enhanced multidetector-row computed tomography (MDCT) prior to transcatheter aortic valve implantation (TAVI) in high-risk patients. MATERIALS AND METHODS: The present single-centre study analysed retrospectively 361 patients who were assessed using MDCT prior to TAVI. CI-AKI was defined as an increase in serum creatinine (SCr) of ≥ 25% or ≥ 0.5 mg/dl in at least one sample over baseline (24 h before MDCT) and at 24, 48, and 72 h after MDCT. RESULTS: A total of 38 patients (10.5%) experienced CI-AKI. As compared to patients without CI-AKI, they presented more frequently with estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2), (81.6% versus 64.4%, p = 0.045) and tended to receive higher volumes of iodinated contrast media (ICM; 55.3% versus 39%, p = 0.057). There was a significant interaction between baseline eGFR and the amount of intravenous ICM administered (pfor interaction = <0.001) identifying the amount of ICM >90 ml as independent predictive factor of CI-AKI only in patients with baseline eGFR <60 ml/min/1.73m(2) (OR 2.615; 95% CI: 1.21-5.64). CONCLUSION: One in ten elderly patients with aortic stenosis undergoing MDCT to plan a TAVI procedure experienced CI-AKI after intravenous ICM injection. Intravenous administration of <90 ml of ICM reduces this risk in patients with or without pre-existing impaired renal function. However, in the majority of patients renal function recovers before the TAVI procedure.

Dose reduction in oncological staging multidetector CT: effect of iterative reconstruction.

OBJECTIVE: To compare radiation exposure and image quality of oncological staging multidetector CT (MDCT) examinations of the chest, abdomen and pelvis with and without iterative reconstruction (IR). METHODS: 40 patients with known malignancy underwent staging CT examinations at two time points. Both CT scans were performed on the same scanner (SOMATOM® Definition Flash, Siemens Healthcare, Forchheim, Germany). For the baseline scan, the tube current-time product was set to 250 mAs [image reconstruction: filtered back projection (FBP)] and for the follow-up scan to 150 mAs [reconstruction: iterative reconstruction (IR)]. Effective radiation doses were estimated based on dose-length products for both baseline and follow-up. Noise measurements in defined regions were compared for FBP and IR. Images were also subjectively evaluated for image quality by three radiologists with different levels of experience. RESULTS: Dose reduction was 44.4±8.2% for reduced-dose CT scans with IR compared with baseline with FBP. Image noise was not significantly different between images reconstructed with FBP and IR. The subjective quality of standard-dose FBP images and reduced-dose iteratively reconstructed CT images were identical. CONCLUSION: Our results show the dose-reducing potential of IR of CT image data in oncological patients. ADVANCES IN KNOWLEDGE: The algorithm tested in the present scientific study allows a >45% dose reduction at maintained image quality.

Novel anticonvulsants for reducing alcohol consumption: A review of evidence from preclinical rodent drinking models.

Alcohol use disorders (AUDs) are a major public health issue and have an enormous social and economic burden in developed, developing, and third-world countries. Current pharmacotherapies for treating AUDs suffer from deleterious side effects and are only effective in preventing relapse in a subset of individuals. This signifies an essential need for improved medications to reduce heavy episodic drinking and alcohol-related problems. Growing literature has provided support for the use of anticonvulsants in suppressing symptoms induced by alcohol withdrawal. Emerging clinical and preclinical evidence suggests that a number of well-tolerated anticonvulsants may also decrease alcohol drinking. This review will focus on recent evidence supporting the efficacy of novel anticonvulsants in reducing voluntary alcohol consumption in rodent models. The data demonstrate that anticonvulsants reduce drinking in standard home cage two-bottle choice paradigms, self-administration of alcohol in operant chambers, and cue- and stress-induced reinstatement of alcohol seeking behaviors in rats and mice. This review also highlights evidence that some anticonvulsants were only moderately effective in reducing drinking in select strains of rodents or models. This suggests that genetics, possible neuroadaptations, or the pharmacological target affect the ability of anticonvulsants to attenuate alcohol consumption. Nonetheless, anticonvulsants are relatively safe, have little abuse potential, and can work in combination with other drugs. The results from these preclinical and clinical studies provide compelling evidence that anticonvulsants are a promising class of medication for the treatment of AUDs.

[Possibilities for exposure reduction in computed tomography examination of acute chest pain]. / Möglichkeiten der Dosisreduktion bei CT-Untersuchungen des akuten Thoraxschmerzes.

CLINICAL/METHODICAL ISSUE: Electrocardiogram-gated (ECG) computed tomography (CT) investigations can be accompanied by high amounts of radiation exposure. This is particularly true for the investigation of patients with unclear and acute chest pain. STANDARD RADIOLOGICAL METHODS: The common approach in patients with acute chest pain is standard spiral CT of the chest. METHODICAL INNOVATIONS: The chest pain or triple-rule-out CT protocol is a relatively new ECG-gated protocol of the entire chest. This article reviews and discusses different techniques for the CT investigation of patients with acute chest pain. PERFORMANCE: By applying the appropriate scan technique, the radiation exposure for an ECG-gated protocol must not necessarily be higher than a standard chest CT scan ACHIEVEMENTS: Aortic pathologies are far better depicted by ECG-gated scan protocols and depending on the heart rate coronary artery disease can also be detected at the same time. PRACTICAL RECOMMENDATIONS: The use of ECG-triggered scans will not support the diagnostics of the pulmonary arteries. However, in unspecific chest pain an ECG-triggered scan protocol can provide information on the differential diagnosis.

Comparative mapping of quantitative trait loci involved in heterosis for seedling and yield traits in oilseed rape (Brassica napus L.).

Little is known about the genetic control of heterosis in the complex polyploid crop species oilseed rape (Brassica napus L.). In this study, two large doubled-haploid (DH) mapping populations and two corresponding sets of backcrossed test hybrids (THs) were analysed in controlled greenhouse experiments and extensive field trials for seedling biomass and yield performance traits, respectively. Genetic maps from the two populations, aligned with the help of common simple sequence repeat markers, were used to localise and compare quantitative trait loci (QTL) related to the expression of heterosis for seedling developmental traits, plant height at flowering, thousand seed mass, seeds per silique, siliques per unit area and seed yield. QTL were mapped using data from the respective DH populations, their corresponding TH populations and from mid-parent heterosis (MPH) data, allowing additive and dominance effects along with digenic epistatic interactions to be estimated. A number of genome regions containing numerous heterosis-related QTL involved in different traits and at different developmental stages were identified at corresponding map positions in the two populations. The co-localisation of per se QTL from the DH population datasets with heterosis-related QTL from the MPH data could indicate regulatory loci that may also contribute to fixed heterosis in the highly duplicated B. napus genome. Given the key role of epistatic interactions in the expression of heterosis in oilseed rape, these QTL hotspots might harbour genes involved in regulation of heterosis (including fixed heterosis) for different traits throughout the plant life cycle, including a significant overall influence on heterosis for seed yield.

[C-arm CT-guided 3D navigation of percutaneous interventions]. / C-Bogen-CT-unterstützte 3D-Navigation perkutaner Interventionen.

So far C-arm CT images were predominantly used for a precise guidance of an endovascular or intra-arterial therapy. A novel combined 3D-navigation C-arm system now also allows cross-sectional and fluoroscopy controlled interventions. Studies have reported about successful CT-image guided navigation with C-arm systems in vertebroplasty. Insertion of the radiofrequency ablation probe is also conceivable for lung and liver tumors that had been labelled with lipiodol. In the future C-arm CT based navigation systems will probably allow simplified and safer complex interventions and simultaneously reduce radiation exposure.

Molecular characterisation and chromosomal localisation of a telomere-like repetitive DNA sequence highly enriched in the C genome of Brassica.

The aim of this work was to find C genome specific repetitive DNA sequences able to differentiate the homeologous A (B. rapa) and C (B. oleracea) genomes of Brassica, in order to assist in the physical identification of B. napus chromosomes. A repetitive sequence (pBo1.6) highly enriched in the C genome of Brassica was cloned from B. oleracea and its chromosomal organisation was investigated through fluorescent in situ hybridisation (FISH) in B. oleracea (2n = 18, CC), B. rapa (2n = 20, AA) and B. napus (2n = 38, AACC) genomes. The sequence was 203 bp long with a GC content of 48.3%. It showed up to 89% sequence identity with telomere-like DNA from many plant species. This repeat was clearly underrepresented in the A genome and the in situ hybridisation showed its B. oleracea specificity at the chromosomal level. Sequence pBo1.6 was localised at interstitial and/or telomeric/subtelomeric regions of all chromosomes from B. oleracea, whereas in B. rapa no signal was detected in most of the cells. In B. napus 18 to 24 chromosomes hybridised with pBo1.6. The discovery of a sequence highly enriched in the C genome of Brassica opens the opportunity for detailed studies regarding the subsequent evolution of DNA sequences in polyploid genomes. Moreover, pBo1.6 may be useful for the determination of the chromosomal location of transgenic DNA in genetically modified oilseed rape.

Tolerance to the discriminative stimulus effects of ethanol following chronic inhalation exposure to ethanol in C57BL/6J mice.

A significant consequence of chronic ethanol (EtOH) exposure is the development of tolerance. The present study was designed to investigate tolerance to the discriminative stimulus properties of EtOH following chronic EtOH exposure. Adult male C57BL/6J mice were trained to discriminate EtOH (1.00 g/kg; i.p.) from saline, using a food-reinforced two-lever operant task. Following acquisition and establishment of criterion discrimination performance, a series of generalization tests were conducted to generate a baseline EtOH dose-response curve with a calculated ED50 dose of 0.42 g/kg. Mice were then placed into control (air) or EtOH inhalation chambers for 64 h. In Experiment 1, discriminative stimulus generalization tests with the EtOH ED50 dose conducted 24 h following chronic EtOH (or air) exposure did not yield significantly different EtOH responding, although a trend towards reduced sensitivity to the EtOH cue (tolerance) was evident. In Experiment 2, a cumulative dosing procedure (ED50=0.37 g/kg) was employed, yielding a baseline EtOH dose-response function with a calculated ED50 dose of 0.37 g/kg. At 24 h following chronic EtOH exposure, re-determination of the EtOH dose-response curve revealed a significant shift to the right, with more than a twofold increase in the ED50 value (ED50=1.09 g/kg) compared to the control air exposure condition (ED50=0.49 g/kg). This apparent tolerance to the EtOH cue dissipated in chronic EtOH-exposed mice tested 48 h following the inhalation treatment (ED50=0.51 g/kg). These results demonstrate tolerance to the discriminative stimulus effects of EtOH in C57BL/6J mice following chronic EtOH exposure in inhalation chambers.

The anticancer drug-DNA complex: femtosecond primary dynamics for anthracycline antibiotics function.

The anthracycline-DNA complex, which is a potent agent for cancer chemotherapy, has a unique intercalating molecular structure with preference to the GC bases of DNA, as shown by Rich's group in studies of single-crystal x-ray diffraction. Understanding cytotoxicity and its photoenhancement requires the unraveling of the dynamics under the solution-phase, physiological condition. Here we report our first study of the primary processes of drug function. In a series of experiments involving the drug (daunomycin and adriamycin) in water, the drug-DNA complexes, the complexes with the four nucleotides (dGTP, dATP, dCTP, and dTTP), and the drug-apo riboflavin-binding protein, we show the direct involvement of molecular oxygen and DNA base-drug charge-separation-the rates for the reduction of the drug and dioxygen indicate the crucial role of drug/base/O(2) in the efficient and catalytic redox cycling. These dynamical steps, and the subsequent reactions of the superoxide product(s), can account for the photoenhanced function of the drug in cells, and potentially for the cell death.

Alcohol withdrawal kindling: mechanisms and implications for treatment.

This article represents the proceedings of a workshop at the 2000 ISBRA Meeting in Yokohama, Japan. The chair was Larry P. Gonzalez. The presentations were (1) EEG indices of sensitization in a murine model of repeated ethanol withdrawals, by Lynn M. Veatch; (2) Long-term changes in central nervous system function after repeated alcohol withdrawals: Recommendations for the treatment of acute withdrawal, by Larry P. Gonzalez; (3) Differential regulation of GABAA and NMDA receptors by repeated ethanol treatment in cultured mammalian neurons, by Maharaj K. Ticku; and (4) Involvement of GABAA and NMDA receptors in alcohol withdrawal kindling: Implications for treatment, by Howard C. Becker.

Animal models of alcohol withdrawal.

One diagnostic criterion of alcohol dependence is the appearance of a withdrawal syndrome when alcohol consumption ceases. Researchers have used various animal models, including isolated brain cells, slices of brain tissue, and intact animals, to study the mechanisms and manifestations of withdrawal. Results from these experimental studies have demonstrated that many consequences of withdrawal found in animals resemble those observed in humans. Such signs and symptoms of alcohol withdrawal include enhanced activity of the autonomic nervous system; body posture and motor abnormalities; hyperexcitability of the central nervous system, including sensory hyperreactivity; convulsions; anxiety; and psychological discomfort. Researchers also have used animal models to study the electrophysiological correlates of withdrawal, as well as neurobiological mechanisms underlying alcohol dependence and withdrawal.

Probing DNA conductivity with photoinduced electron transfer and scanning tunneling microscopy.

Abstract The possibility that the stacked DNA bases can mediate vectorial electron transfer has been examined using two different approaches. Experiments on photoinduced electron transfer with intercalated donors and acceptors (either randomly bound or linked dyads of ruthenium complex and viologen) indicate that while DNA may be a better medium than acetonitrile for electron transfer over short distances (2-3-base pair, equivalent to 10-14Å centre-to-centre separation), it is a poor medium for transport over larger separations. Attempts to measure conductivity of individual DNA molecules using scanning tunneling microscopy to image mixed monolayers of mercaptohexanol (MCH) and 30-mer or 10-mer DNAs with alkanethiol linkers also indicate that DNA in its native state is a poor conductor. AFM images of the DNA/MCH mixed monolayers show that the DNA molecules extend vertically upward from the surface in such surface architectures.

Repeated ethanol withdrawal experience selectively alters sensitivity to different chemoconvulsant drugs in mice.

Repeated ethanol withdrawal experience has been shown to result in exacerbated seizures associated with future withdrawal episodes. This sensitization of the withdrawal response has been postulated to represent a "kindling" phenomenon. The present study employed an established model of repeated ethanol withdrawals to examine the potential role of GABA(A), and NMDA and non-NMDA glutamate receptor systems in mediating enhanced seizure activity, as assessed by sensitivity to seizures induced by pentylenetetrazol (PTZ), NMDA, and kainic acid (KA) i.v. infusions, respectively. Adult C3H mice were chronically exposed to ethanol vapor in inhalation chambers. A multiple withdrawal (MW) group received four cycles of 16-h ethanol vapor exposure interrupted by 8-h periods of abstinence; a single withdrawal (SW) group was tested after a single 16-h bout of ethanol intoxication; and the third group was ethanol-naive, serving as controls (C). Results indicated that the MW group evidenced significantly lower PTZ and NMDA seizure thresholds compared to SW and C groups at 8 and 24 h post-withdrawal. In contrast, MW and SW groups exhibited reduced sensitivity (higher seizure threshold) to KA in comparison to controls, and this effect only emerged at 24 h post-withdrawal. Further, MW mice required significantly less additional PTZ or NMDA to induce more severe convulsions once initial signs of seizures were elicited. Conversely, latency and amount of KA required to transition from initial seizure signs to more severe end-stage convulsions was significantly greater for MW and SW groups compared to controls. Taken together, these results suggest that repeated ethanol withdrawal experience does not result in a global non-specific lowering of threshold to convulsive stimuli, but rather, selective changes in CNS mechanisms associated with neural excitability may underlie potentiated withdrawal responses. Thus, reduced GABA(A) receptor function and increased NMDA receptor activity may become exaggerated as a consequence of repeated withdrawal experience, while reduced sensitivity to KA induced seizures may represent a compensatory response to withdrawal-related CNS hyperexcitability.

Single and repeated episodes of ethanol withdrawal increase adenosine A1, but not A2A, receptor density in mouse brain.

A history of multiple ethanol withdrawal experiences has been shown to exacerbate the severity of future withdrawal episodes, and this sensitization of the withdrawal response has been hypothesized to represent a 'kindling' phenomenon. Since adenosine functions as an inhibitory modulator of seizure activity and may interact with ethanol to influence neuronal excitability, the present study was conducted to examine the effects of single and repeated episodes of ethanol withdrawal on adenosine A1 and A2A receptors in adult C3H/He mice. Mice were chronically exposed to ethanol vapor in inhalation chambers and tested for withdrawal seizures following multiple withdrawal (MW) experience (four cycles of 16 h ethanol intoxication interrupted by 8 h periods of abstinence), single withdrawal experience following 16 h (SW) or 64 h (CE) continuous ethanol intoxication, or no ethanol exposure (controls). Separate groups of mice from each withdrawal condition were used to generate pooled cortical and striatal tissue for ligand saturation experiments using [3H]cyclohexyladenosine to label A1 receptors and [3H]CGS 21680 to label A2A receptors. Results indicated that withdrawal seizures were significantly more severe in mice with multiple withdrawal experience in comparison to animals that experienced only a single withdrawal episode, even when total amount of ethanol exposure was equated among groups. The density of A1 receptors in cerebral cortex was significantly increased over controls 8 h following final ethanol withdrawal by approximately 35% in SW and CE groups, with the largest increase observed in the MW group (56%). Withdrawal treatment groups did not differ in cortical A1 binding sites immediately upon withdrawal from ethanol, and no significant differences in binding of [3H]CGS 21680 to striatal A2A receptors were observed following ethanol withdrawal. Ethanol exposure and withdrawal did not significantly alter ligand affinity for either adenosine receptor. These results indicate that adenosine A1 receptors are selectively upregulated during ethanol withdrawal and that the degree of upregulation may be enhanced following multiple withdrawal episodes. Further, these observations suggest that the upregulation of brain A1 receptors during ethanol withdrawal may represent a compensatory inhibitory response to increased seizure severity associated with repeated episodes of ethanol withdrawal.

Kindling in alcohol withdrawal.

In many alcoholics, the severity of withdrawal symptoms increases after repeated withdrawal episodes. This exacerbation may be attributable to a kindling process. Kindling is a phenomenon in which a weak electrical or chemical stimulus, which initially causes no overt behavioral responses, results in the appearance of behavioral effects, such as seizures, when it is administered repeatedly. Both clinical and experimental evidence support the existence of a kindling mechanism during alcohol withdrawal. Withdrawal symptoms, such as seizures, result from neurochemical imbalances in the brain of alcoholics who suddenly reduce or cease alcohol consumption. These imbalances may be exacerbated after repeated withdrawal experiences. The existence of kindling during withdrawal suggests that even patients experiencing mild withdrawal should be treated aggressively to prevent the increase in severity of subsequent withdrawal episodes. Kindling also may contribute to a patient's relapse risk and to alcohol-related brain damage and cognitive impairment.