Optimizing Antibiotic Therapy for Intravenous Drug Users: A Narrative Review Unraveling Pharmacokinetics/Pharmacodynamics Challenges

Intravenous drug users (IVDUs) face heightened susceptibility to life-threatening gram-positive bacterial infections, particularly methicillin-resistant Staphylococcus aureus (MRSA). While the standard antibiotic dosing strategies for special patients, such as obese or critically ill individuals, are known to be inadequate, raising concerns about treatment efficacy, a similar sort of understanding has not been assessed for IVDUs yet. With this in mind, this review examines the pharmacokinetic/pharmacodynamic characteristics of antibiotics commonly used against gram-positive bacteria in IVDUs. Focusing on daptomycin, vancomycin, teicoplanin, aminoglycosides, and the novel lipoglycopeptide dalbavancin, the study reveals significant pharmacokinetic variations in IVDUs, suggesting the need for personalized dosing. Concomitant opioid substitution therapy and other factors, such as malnutrition, contribute to altered pharmacokinetics/pharmacodynamics, emphasizing the importance of targeted therapeutic drug monitoring. Overall, our study calls for increased awareness among clinicians regarding the unique pharmacokinetic/pharmacodynamic challenges in IVDUs and advocates for tailored antibiotic dosing strategies to enhance treatment outcomes in this marginalized population.

The possible role of serum bactericidal titres in long-term suppressive antibiotic treatment for infective endocarditis: report of three cases

INTRODUCTION

long term suppressive antibiotic treatment may be the only feasible option for patients with infective endocarditis (IE) not suitable for surgery.

CASE REPORTS

we present three cases of prosthetic valve endocarditis (PVE) caused by Enterococcus faecalis and Streptococcus gallolyticus which could not undergo surgical intervention due to high risk. Despite this, patients were successfully managed only by medical approach. Following intravenous targeted antimicrobial therapy, patients received chronic suppressive antimicrobial therapy (SAT) for at least twelve months with oral amoxicillin. In all cases, no further febrile episodes nor bacteraemia were observed and in two cases a complete positron emission tomography (PET) response was achieved. Due to a priori uncertainty about antimicrobial exposure during oral SAT, serum bactericidal titres (SBTs) were obtained and compared to those obtained during parenteral therapy.

CONCLUSIONS

long term oral amoxicillin was effective and well-tolerated. SBTs after switch to oral therapy were quite heterogeneous, in some cases not reaching the conventionally established titre to assess bactericidal effect (1:8).Key pointsendovascular infection in non-suitable-for-surgery patients can be managed with long-term oral suppressive therapy.serum bactericidal assay confirmed high effectiveness of parenteral antibiotic therapy.serum bactericidal assay showed highly variable titres during oral therapy.

Is a radiological score needed to define the severity of Nontuberculous mycobacteria lung disease?

High-resolution CT-scan (HRCT) plays a major role in the diagnosis of Nontuberculous mycobacteria lung disease (NTM-LD), but its role in follow-up is controversial. Our aim was first to conceive a radiological score able to quantify the severity of pulmonary involvement by NTM infection and, second, to check its association with the NTM-LD clinical burden. We also intended, if possible, to verify the potential influence of NTM specific treatment on the radiological score. We retrospectively collected the clinical, microbiological and radiological data of all patients who were admitted to our hospital from 1 January 2012 to 1 January 2020 with a confirmed diagnosis of NTM-LD. A radiological score was applied to evaluate lung involvement on HRCT at diagnosis and at 6-18 months follow-up. Twenty-eight patients with NTM-LD performed follow-up HRCT. No association was found between radiological and clinical score (Spearman R -0.05, 95%CI -0.41 to 0.33). Repeated measures analysis showed a significant increase in radiological score over time (change 1.11, 95%CI 0.10 to 2.11; p-value 0.032), while Mann-Whitney test did not show any difference between treated and untreated patients (p value 0.922). Further studies are needed to assess the usefulness of routine radiological follow-up in patients with NTM-LD.

Competing-risk analysis of coronavirus disease 2019 in-hospital mortality in a Northern Italian centre from SMAtteo COvid19 REgistry (SMACORE)

An accurate prediction of the clinical outcomes of European patients requiring hospitalisation for Coronavirus Disease 2019 (COVID-19) is lacking. The aim of the study is to identify predictors of in-hospital mortality and discharge in a cohort of Lombardy patients with COVID-19. All consecutive hospitalised patients from February 21st to March 30th, 2020, with confirmed COVID-19 from the IRCCS Policlinico San Matteo, Pavia, Lombardy, Italy, were included. In-hospital mortality and discharge were evaluated by competing risk analysis. The Fine and Gray model was fitted in order to estimate the effect of covariates on the cumulative incidence functions (CIFs) for in-hospital mortality and discharge. 426 adult patients [median age 68 (IQR 56 to 77 years)] were admitted with confirmed COVID-19 over a 5-week period; 292 (69%) were male. By 21 April 2020, 141 (33%) of these patients had died, 239 (56%) patients had been discharged and 46 (11%) were still hospitalised. Among these 46 patients, updated as of 30 May, 2020, 5 (10.9%) had died, 8 (17.4%) were still in ICU, 12 (26.1%) were transferred to lower intensity care units and 21 (45.7%) were discharged. Regression on the CIFs for in-hospital mortality showed that older age, male sex, number of comorbidities and hospital admission after March 4th were independent risk factors associated with in-hospital mortality. Older age, male sex and number of comorbidities definitively predicted in-hospital mortality in hospitalised patients with COVID-19.

Running out of bullets: The challenging management of acute hepatitis and SARS-COV-2 from the SMatteo COvid19 Registry (SMACORE)

Liver impairment is frequent in patients with novel coronavirus disease (COVID-19) and direct viral tropism for the liver has been proven. Since several of the currently administered drugs against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are possibly hepatotoxic, the management of patients with COVID-19 and liver failure is still an almost unexplored field. Taking this challenging case of acute HBV with persistent hyperbilirubinemia and SARS-COV-2 infection with respiratory distress as a starting point, we here loop through this condition. Where the available therapeutic options are scarce, we here propose hemoperfusion (HP) as an attractive alternative to both delay any late-stage progression of hyper inflammation process in COVID-19 and remove the toxins involved in acute liver failure.

The obesity paradox: Analysis from the SMAtteo COvid-19 REgistry (SMACORE) cohort

BACKGROUND AND AIMS

Obesity has been suggested as a possible risk factor for a more severe course of COVID-19; however, conclusive evidence is lacking and few studies have investigated the role of BMI as a risk factor for admission to intensive care unit (ICU) and mortality. We retrospectively analyzed a COVID-19 cohort recruited during the first 40 days of the epidemic in Italy. We examined the association between obesity and 30-day mortality, admission to ICU, mortality and length of hospital stay in patients with COVID-19.

METHODS AND RESULTS

Demographic, clinical and outcome data were retrospectively analyzed in 331 patients with COVID-19 admitted to hospital between 21 February and 31 March 2020. The predictive effect of obesity on mortality was assessed using a Cox proportional-hazard regression model, its effect on ICU admission and mortality in the ICU using logistic regressions, and its effect on length of hospital stay using a linear regression. Seventy-four of 331 patients had a BMI ≥30 kg/m2. Among obese patients, 21 (28.4%) required admission in ICU and 25 died (33.8%). After controlling for sex, age, comorbidities and clinical data, obesity was not significantly associated with mortality, mortality in ICU and length of hospital stay. The effect of obesity on ICU admission remained significant after controlling for sex, age, interstitial lung disease, heart disease and serum C-reactive protein.

CONCLUSIONS

Obese patients with COVID-19 were more likely to be admitted to ICU than non-obese patients. However, there were no significant differences in mortality between the two groups.

Tocilizumab for Treatment of Severe COVID-19 Patients: Preliminary Results from SMAtteo COvid19 REgistry (SMACORE)

Objective: This study aimed to assess the role of Tocilizumab therapy (TCZ) in terms of ICU admission and mortality rate of critically ill patients with severe COVID-19 pneumonia. Design: Patients with COVID-19 pneumonia were prospectively enrolled in SMAtteo COvid19 REgistry (SMACORE). A retrospective analysis of patients treated with TCZ matched using propensity score to patients treated with Standard Of Care (SOC) was conducted. Setting: The study was conducted at IRCCS Policlinico San Matteo Hospital, Pavia, Italy, from March 14, 2020 to March 27, 2020. Participants: Patients with a confirmed diagnosis of COVID-19 hospitalized in our institution at the time of TCZ availability. Interventions: TCZ was administered to 21 patients. The first administration was 8 mg/kg (up to a maximum 800 mg per dose) of Tocilizumab intravenously, repeated after 12 h if no side effects were reported after the first dose. Main Outcomes and Measures: ICU admission and 7-day mortality rate. Secondary outcomes included clinical and laboratory data. Results: There were 112 patients evaluated (82 were male and 30 were female, with a median age of 63.55 years). Using propensity scores, the 21 patients who received TCZ were matched to 21 patients who received SOC (a combination of hydroxychloroquine, azithromycin and prophylactic dose of low weight heparin). No adverse event was detected following TCZ administration. This study found that treatment with TCZ did not significantly affect ICU admission (OR 0.11; 95% CI between 0.00 and 3.38; p = 0.22) or 7-day mortality rate (OR 0.78; 95% CI between 0.06 and 9.34; p = 0.84) when compared with SOC. Analysis of laboratory measures showed significant interactions between time and treatment regarding C-Reactive Protein (CRP), alanine aminotransferase (ALT), platelets and international normalized ratio (INR) levels. Variation in lymphocytes count was observed over time, irrespective of treatment. Conclusions: TCZ administration did not reduce ICU admission or mortality rate in a cohort of 21 patients. Additional data are needed to understand the effect(s) of TCZ in treating patients diagnosed with COVID-19.

Clinical characteristics of coronavirus disease (COVID-19) early findings from a teaching hospital in Pavia, North Italy, 21 to 28 February 2020

We describe clinical characteristics, treatments and outcomes of 44 Caucasian patients with coronavirus disease (COVID-19) at a single hospital in Pavia, Italy, from 21-28 February 2020, at the beginning of the outbreak in Europe. Seventeen patients developed severe disease, two died. After a median of 6 days, 14 patients were discharged from hospital. Predictors of lower odds of discharge were age > 65 years, antiviral treatment and for severe disease, lactate dehydrogenase > 300 mg/dL.

Negative symptom severity at discharge from an index hospitalization and subsequent use of psychiatric care resources: A retrospective 1-year follow-up study on 450 patients with schizophrenia spectrum disorders

Negative symptoms of schizophrenia have a great impact on patients' functioning and are among the most important contributors to subject's disability. However, few studies have assessed the role of type and severity of symptomatology of schizophrenia on the psychiatric care resource utilization. We investigated if the clinical profile of patients at discharge from an index hospitalization might be associated with a different use of psychiatric care resources in the subsequent 1-year period in a large population of patients with schizophrenia spectrum disorders. Clinical records of 450 patients with schizophrenia spectrum disorders admitted in an acute psychiatric inpatient service and subsequently followed in the outpatient services of the same Department were reviewed. Patients with more severe negative symptoms at discharge from hospital showed a higher number and duration of hospitalizations in the 1-year follow-up, as well as a higher number of rehabilitative residential admissions than patients with milder severity of negative symptoms. The same was true for patients with predominant negative symptoms. A global resource utilization index indicated a higher use of psychiatric resources in patients with higher severity of negative symptoms. In conclusion, showing moderate to severe negative symptoms versus positive symptoms at discharge from a hospitalization for an acute exacerbation of schizophrenia spectrum disorder does predict a higher use of psychiatric care resources. This underlines the importance of relieving negative symptoms even in the acute phase of treatment and the need to develop more effective treatments for this symptom dimension.

The impact of HIV infection and men who have sex with men status on hepatitis A infection: The experience of two tertiary centres in Northern Italy during the 2017 outbreak and in the 2009-2016 period

Hepatitis A is a self-limiting infection representing the most common cause of viral hepatitis worldwide. Despite being a low incidence region, in the European Union, an increasing number of cases have been reported since summer 2016, resulting in a large outbreak in 2017, involving mainly men who have sex with men (MSM). Some reports described a different clinical course of hepatitis A virus in patients infected by human immunodeficiency virus (HIV) or MSM. We consecutively collected all the hospitalized cases of hepatitis A referred to two tertiary centres in Northern Italy in 2017 and retrospectively analysed the electronic records of the 2009-2016 period (pre-2017). We evaluated demographics data, risk factors, comorbidities and laboratory results to see whether MSM status or HIV infection influenced the disease. Overall, 117 cases were identified in 2017:107 (91%) were male, 78 reported themselves as MSM (66%) and 17 (14.5%) were infected by HIV. For the pre-2017 period, 48 cases were reported: 29 (60%) were male and 3 (6.2%) were infected by HIV. After stratification for HIV infection, MSM status and occurrence period, no differences were found in aspartate aminotransferase, alanine aminotransferase, γ-glutamyl transpeptidase; bilirubin, alkaline phosphatase and bilirubin values, hospitalization length, HIV viral load and CD4 + cells count. HIV-positive patients presented a higher number of patients with INR > 1.5 at admission. MSM status and HIV infection did not affect neither the clinical course nor the severity of hepatitis A.

How to Study Boron Biodistribution in Liver Metastases from Colorectal Cancer

The purpose of this study was to evaluate boron distribution for a safe and effective BNCT (Boron Neutron Capture Therapy) of liver metastases. Samples both from healthy and tumour liver parenchyma were analysed, after i.v. boron administration, by: alpha particles counting under neutron irradiation; morphological analysis by standard haematoxylin-eosin staining; neutron autoradiography. Our method was unaffected by the cytological heterogeneity inside tumour nodules; it demonstrated selective boron distribution in tumour tissue and predicted estimated mean therapeutic doses in tumour and safety doses in healthy tissue. The time interval for efficient BNCT was 2 to 4 hours after i.v. boron administration.

The effect of demonstrator age and number on duration of socially-induced food preferences in house mouse (Mus domesticus)

Present research was undertaken to investigate whether the transfer of food preference from a demonstrator mouse to an observer can be influenced by their relative age. In experiment 1 an adult female mouse, the observer, was allowed to interact with a recently-fed demonstrator which was a pup of her litter or an adult female mouse. The observer was then tested to assess whether it acquired a preference for the demonstrator's diet. The results showed that a pup demonstrator's influence on an adult's food preference is shorter-lasting than an adult demonstrator's influence. Experiment 2 was aimed to investigate whether many demonstrators have an additive effect in influencing their observer's choice. The results indicated that multiple pup demonstrations do not increase longevity of food preferences induced by pup demonstrators. Moreover, the longevity of an adult observer's preference for its demonstrator's food is reduced by the exposure to multiple adult demonstrators. Results are discussed in terms of demonstrator's reliability and of social constraints that could affect social transfer of food information in the house mouse.

Patterns of brain structural changes in first-contact, antipsychotic drug-naive patients with schizophrenia

BACKGROUND AND PURPOSE

Previous studies have suggested that structural changes do occur in the brain of patients with schizophrenia compared with healthy control participants. However, findings from such studies are inconclusive, probably because of the different methodologic approaches, the clinical heterogeneity of patient samples, and also the fact that patients enrolled were treated with antipsychotic drugs. The aim of this study was to investigate brain GM volumes and intrinsic structural WM changes in first-contact, antipsychotic drug-naïve patients with schizophrenia.

MATERIALS AND METHODS

A total of 43 first-contact, drug-naïve, patients with schizophrenia and 17 age-matched control participants were studied. All participants underwent T1-weighted MR imaging and DTI scans. Voxel-based morphometry and tract-based spatial statistics were used to compare GM volumes and WM DTI metrics between groups. MR imaging measures were correlated with the duration of the untreated psychosis and the clinical positive and negative symptoms.

RESULTS

Compared with control participants, patients with schizophrenia showed smaller volumes of the temporal, parietal, and occipital GM, and a pattern of decreased mean diffusivity and increased fractional anisotropy in the brain stem and cerebellum bilaterally, interhemispheric and cortico-cortical connections bilaterally, and right anterior and posterior limb of the internal capsule. In patients, decreased mean diffusivity and increased fractional anisotropy in several brain regions were related to a longer duration of the untreated psychosis and the severity of positive symptoms.

CONCLUSIONS

First-contact, drug-naïve, patients with schizophrenia present with volumetric and DTI changes, which correlated with their clinical features. This study increases our knowledge on the neural networks involved in the pathophysiologic mechanisms of schizophrenia.

Is your choice my choice? The owners' effect on pet dogs' (Canis lupus familiaris) performance in a food choice task

This study investigates the influence of owners on their dogs' performance in a food choice task using either different or equal quantities of food. Fifty-four pet dogs were tested in three different conditions. In Condition 1 we evaluated their ability to choose between a large and small amount of food (quantity discrimination task). In Condition 2 dogs were again presented with a choice between the large and small food quantity, but only after having witnessed their owner favouring the small quantity. In Condition 3 dogs were given a choice between two equally small quantities of food having witnessed their owner favouring either one or the other. A strong effect of the owner on the dogs' performance was observed. In Condition 1 dogs as a group chose significantly more often the large food quantity, thus showing their ability to solve the quantity discrimination task. After observing their owner expressing a preference for the small food quantity they chose the large quantity of food significantly less than in the independent choice situation. The tendency to conform to the owner's choice was higher when the dogs had to choose between equally small quantities of food (Condition 3) rather than between a large and a small one (Condition 2). These results provide evidence that dogs can be influenced by their owners even when their indications are clearly in contrast with direct perceptual information, thus leading dogs to ultimately make counterproductive choices.

Chronic exposure to low doses bisphenol A interferes with pair-bonding and exploration in female Mongolian gerbils

Estrogenic endocrine disruptors, synthetic or naturally occurring substances found in the environment, can interfere with the vertebrate endocrine system and, mimicking estrogens, interact with the neuroendocrine substrates of behavior. Since species vary in their sensitivity to steroids, it is of great interest to widen the range of species included in the researches on neurobehavioral effects of estrogenic endocrine disruptors. We examined socio-sexual and exploratory behavior of Mongolian gerbil females (Meriones unguiculatus), a monogamous rodent, in response to chronic exposure to the estrogenic endocrine disruptor bisphenol A. Paired females were daily administered with one of the following treatments: bisphenol A (2 or 20 microg/kg body weight/day); 17alpha-ethynil estradiol (0.04 microg/kg body weight/day 17alphaE); oil (vehicle). Females were treated for 3 weeks after pairing. Starting on day of pairing, social interactions within pairs were daily recorded. Three weeks after pairing, females were individually tested in a free exploratory paradigm. Bisphenol A and 17alphaE affected male-female social interactions by increasing social investigation. Bisphenol A reduced several exploratory parameters, indicating a decreased exploratory propensity of females. These results highlight the sensitivity of adult female gerbils to bisphenol A during the hormonally sensitive period of pair formation, also considering that the bisphenol A doses tested are well below the suggested human tolerable daily intake.

AFLP to assess genetic variation in laboratory gerbils (Meriones unguiculatus)

The amplified fragment length polymorphism (AFLP) technique has been increasingly employed for characterizing inbred breeds of animals and detecting strain-specific polymorphisms. The majority of animals studies conducted in biomedical research are performed on rodent species, among which laboratory-reared Mongolian gerbils can be included. Despite the wide use of gerbils in scientific studies, their genetics has rarely been studied. Therefore we investigated the genetic differentiation of laboratory bred gerbils by means of AFLP markers. Six EcoRI/TaqI primer combinations were selected among 13 different combinations to assess the genetic polymorphisms in four stocks of animals: Charles River (CR), Harlan (Ha), Parma (Pr), and Crossbred (Cb). CR and Ha gerbils were purchased from commercial vendors, while Pr and Cb were derived from animals bred in our animal colony. A total of 228 fragments ranging between 70 and 650 bp were obtained. The mean percentage of polymorphic loci across primer combinations was 7.5%. Calculation of genetic distances through application of different algorithms (Nei's, BSI, and Jaccard's indexes) confirmed the poor genetic diversity between stocks. Nevertheless, a differentiation of the Pr and Cb stocks from the more homogeneous CR and Ha was revealed, in agreement with the different breeding derivation and management of the stocks.

Quetiapine, clozapine, and olanzapine in the treatment of tardive dyskinesia induced by first-generation antipsychotics: a 124-week case report

Our report of a patient with severe tardive dyskinesia (TD) who has been exposed to both typical antipsychotic and clozapine, olanzapine and quetiapine during a 124-week follow-up period supports the possible beneficial effect of atypical antipsychotics on pre-existing symptoms of TD. Persistently high AIMS scores during all the periods of treatment with typical antipsychotics contrast strongly with the drop in scores that occurs in strict chronological sequence after switching to both clozapine (45%), olanzapine (27.8%) and quetiapine (85%). Since the reversal to haloperidol from the three atypical agents was systemically associated with a return to high AIMS scores, it seems likely that the improvement noted with clozapine, olanzapine and quetiapine represents a temporary symptomatic effect rather than a sustained resolution of the disorder. The olanzapine-clozapine-quetiapine rank order of increasing effectiveness against TD symptoms suggests that this property, although shared by the atypical antipsychotics, is to some degree drug-specific. Patient- and/or drug-dependent mechanisms may be involved in this gradient of effect.

How to decrease the non-compliance in a clinical trial

BACKGROUND

A high compliance is an important scientific objective for a multicenter clinical trial and also an ethical responsibility. Some of non-compliance causes can be prevented during the enrollment phase by an accurate selection of subjects (quality of recruitment), other can be controlled after the recruitment, by a good organization of follow-up tests and visits (quality of organization).

METHODS

The policy adopted in the Operative Center of the Delegazione Alto Lario della Lega Italiana per la Lotta contro i Tumori di Gravedona (Como) for obtaining a high compliance of women recruited in the Italian Tamoxifen Prevention Study are illustrated.

RESULTS

The non-compliance rate of this center is low: 5.6 vs 23.3% of the whole Italian trial.

CONCLUSIONS

The low non-compliance demonstrates the efficacy of the policy adopted.

Sex differences in conditioned taste aversion and in the effects of exposure to a specific pulsed magnetic field in deer mice Peromyscus maniculatus

Although conditioned taste aversion (CTA) has been investigated and described in laboratory rodents and domestic animals, less is known regarding wild rodents. Here, we describe CTA in males and females of a "wild" species of rodent, the deer mouse (Peromyscus maniculatus). In addition, as CTA has often been induced by exposure to intense electromagnetic, X or gamma, radiation, in a second study, we also investigated the effects of a specifically designed, pulsed extremely low-frequency and low-intensity magnetic field on the flavor preferences of male and female deer mice. The results of these investigations showed that: (i) deer mice quickly developed a marked CTA for a novel flavor after a single pairing with LiCl; (ii) although the intensity of the CTA was the same in males and females, there was a sex difference in the duration of the flavor aversion, with males displaying it for a longer period (4 days) than females (3 days); (iii) both males and females showed a rapid and complete extinction of the aversion, in contrast to what has been reported for laboratory rodents; (iv) there was no recovery of CTA on re-test 10 days after extinction; (v) neither male or female deer mice developed a taste aversion as a consequence of exposure to a weak electromagnetic field; and (vi) there was a sex difference in response to the magnetic field, with exposure to the magnetic field significantly enhancing novel taste preference in male but not in female deer mice. Overall, our results show that there are several sex differences in the behavior of deer mice, both in the characteristics of the CTA and in the response to magnetic field exposure. The sex differences are discussed in terms of a sexually dimorphic sensitivity to experimental manipulation and the induction of stress and/or anxiety.

Learning to cope with two different food distributions: the performance of house mice (Mus musculus domesticus)

Search abilities of mice (Mus musculus domesticus) were evaluated using an arena closed by a ceiling in which 9 food sources (which mice could reach standing on their hind legs) could be arranged according to 2 configurations: a 3 x 3 square matrix and 3 clusters each containing 3 food sources. Testing conditions prevented olfactory and visual cues from being left after visits to food sources, and mice were able to choose alternative routes between food sources. Results showed that mice were more efficient with the matrix than with the cluster configuration. Sex differences were observed: Females improved their performance with both configurations, whereas males improved only with the matrix one. Mice did not develop evident search strategies that would minimize task complexity. Comparison with data published on capuchin monkeys revealed differences, with monkeys performing better with the cluster configuration than with the matrix and applying searching strategies.

Radioimmunoassisted surgery for lung metastases from colorectal cancer: results and perspectives

The high incidence of resectable lung metastases from colorectal cancer and the very poor prognosis of untreated patients (less than 24-month survival) has promoted the surgical approach to treatment. Since the main aims of this kind of surgery are the complete resection of the tumor, the preservation of tumor-free parenchyma, and a minimal surgical trauma, innovative surgical techniques have been developed. We report on our experience in the radioimmunoassisted pulmonary metastasectomy by the use of a hand-held gamma-detecting probe (GDP) and describe the application of the intraoperative radioimmunolocalization of tumor to video-assisted minimally invasive surgery.

Social learning of a food preference in male and female Mongolian gerbils is facilitated by the anxiolytic, chlordiazepoxide

Social transmission of a food preference in Mongolian gerbils (Meriones unguiculatus) depends on the presence of a social bond between the interacting animals. An "observer" gerbil can acquire a preference for a novel food item from a familiar and, or related "demonstrator" animal. However, exposure to an unfamiliar and unrelated demonstrator gerbil does not lead to acquisition of a food preference, even though the extent of social interaction and likelihood of transmission of food information is unaffected. Likewise, individual preexposure to a novel food does not affect diet preference in individual animals. Here we show that oral, nongavage, administration of the benzodiazepine anxiolytic, chlordiazcpoxide (CDP, 2.5, 5, and 10 mg/kg) has significant dose-associated differential facilitatory effects on social learning in male and female gerbils, while having no significant effects on either individual learning or total food consumption. These results suggest that the CDP mediated reduction of the anxiety associated with the interactions between unfamiliar/unrelated gerbils facilitates social learning. These findings also rise the possibility of sex differences in socially related anxiety and the effects of CDP on social learning in gerbils.

Kinship and familiarity as factors affecting social transfer of food preferences in adult Mongolian gerbils (Meriones unguiculatus)

Experiments were carried out with Mongolian gerbils (Meriones unguiculatus) to assess whether a socially mediated acquisition of diet selection exists in this species. Results showed that a gerbil was influenced in its diet choices by information extracted during a brief period of interaction with a familiar conspecific that had recently eaten a novel food. Data revealed that the acquisition of a food preference from a conspecific depends on the existence of a social bond between the interacting gerbils. Either genetic relatedness (being brother or sister raised in different litters) or familiarity (being bred in the same litter or being member of a reproductive pair) is necessary for the transfer of information. Unfamiliar and unrelated observer gerbils did not selectively choose their demonstrator's food.

Can Social Behaviour Influence Food Preference of Wild Mice, Mus Domesticus, in Confined Field Populations?

The role of social transmission in directing food preference was assessed in adult wild mice living in seminatural outdoor enclosures located in south-eastern Australia. We first examined whether mice recently fed one novel food and then released back into the enclosure (demonstrator mice) influenced the food preference of mice presented with a choice between that novel food and one other novel food. Then we examined the food preference of mice presented with a novel food and their staple food, after demonstrator mice were fed with the novel food and returned to the enclosure. The main results were as follows: (i) mice given a choice between two novel foods, in the presence of demonstrator mice, consumed significantly more of the novel food to which demonstrator mice had been exposed; and (ii) mice given a choice of one novel food and their staple food, in the presence of demonstrator mice that had been exposed to the novel food, ate similar amounts of the two foods. The adaptive value of different strategies of food selection is discussed.