Chapter 11: Astrobiology Education, Engagement, and Resources.

Although astrobiology is a relatively new field of science, the questions it seeks to answer (e.g., "What is life?" "What does life require?") have been investigated for millennia. In recent decades, formal programs dedicated specifically to the science of astrobiology have been organized at academic, governmental, and institutional scales. Constructing educational programs around this emerging science relies on input from broad expertise and backgrounds. Because of the interdisciplinary nature of this field, career pathways in astrobiology often begin in more specific fields such as astronomy, geology, or biology, and unlike many other sciences, typically involve substantial training outside one's primary discipline. The recent origin of astrobiology as a field of science has led to strong collaborations with education research in the development of astrobiology courses and offers a unique instructional laboratory for further pedagogical studies. This chapter is intended to support students, educators, and early career scientists by connecting them to materials and opportunities that the authors and colleagues have found advantageous. Annotated lists of relevant programs and resources are included as a series of appendices in the supplementary material.

Chapter 1: The Astrobiology Primer 3.0.

The Astrobiology Primer 3.0 (ABP3.0) is a concise introduction to the field of astrobiology for students and others who are new to the field of astrobiology. It provides an entry into the broader materials in this supplementary issue of Astrobiology and an overview of the investigations and driving hypotheses that make up this interdisciplinary field. The content of this chapter was adapted from the other 10 articles in this supplementary issue and thus represents the contribution of all the authors who worked on these introductory articles. The content of this chapter is not exhaustive and represents the topics that the authors found to be the most important and compelling in a dynamic and changing field.

Perturbation of red cell membrane structure during intracellular maturation of Plasmodium falciparum.

An experimental approach, which in this study was applied to the malarial system, can be used to analyze the molecular structure and organization of individual phospholipids in a wide variety of biological membranes. Electron spin resonance spectroscopy was used to investigate the structural modifications of the major red cell phospholipids that occur in erythrocyte membranes infected with the human malarial parasite, Plasmodium falciparum. These modifications were correlated with the intracellular developmental stage of the parasite. Phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine were increasingly disordered (fluidized) as infection progressed. This disordering occurred at different rates and to varying extents.

Evaluating feasibility of an automated 3-dimensional scanner using Raman spectroscopy for intraoperative breast margin assessment.

Breast conserving surgery is the preferred treatment for women diagnosed with early stage invasive breast cancer. To ensure successful breast conserving surgeries, efficient tumour margin resection is required for minimizing tumour recurrence. Currently surgeons rely on touch preparation cytology or frozen section analysis to assess tumour margin status intraoperatively. These techniques have suboptimal accuracy and are time-consuming. Tumour margin status is eventually confirmed using postoperative histopathology that takes several days. Thus, there is a need for a real-time, accurate, automated guidance tool that can be used during tumour resection intraoperatively to assure complete tumour removal in a single procedure. In this paper, we evaluate feasibility of a 3-dimensional scanner that relies on Raman Spectroscopy to assess the entire margins of a resected specimen within clinically feasible time. We initially tested this device on a phantom sample that simulated positive tumour margins. This device first scans the margins of the sample and then depicts the margin status in relation to an automatically reconstructed image of the phantom sample. The device was further investigated on breast tissues excised from prophylactic mastectomy specimens. Our findings demonstrate immense potential of this device for automated breast tumour margin assessment to minimise repeat invasive surgeries.

Nucleotide Availability in Maize (Zea mays L.) Root Tips (Estimation of Free and Protein-Bound Nucleotides Using 31P-Nuclear Magnetic Resonance and a Novel Protein-Ligand-Binding Assay).

Sequestration of nucleotides in cells through protein binding could influence the availability of nucleotides and free energy for metabolic reactions and, therefore, affect rates of physiological processes. We have estimated the proportion of nucleotides bound to proteins in maize (Zea mays L.) root tips. Binding of nucleoside mono- and diphosphates to total root-tip protein was studied in vitro using high-performance liquid chromatography and a new ligand-binding technique. We estimate that approximately 40% of the ADP, 65% of the GDP, 50% of the AMP, and virtually all the GMP in aerobic cells are bound to proteins. In hypoxic cells, free concentrations of these nucleotides increase proportionately much more than total intracellular concentrations. Little or no binding of CDP, UDP, CMP, and UMP was observed in vitro. Binding of nucleoside triphosphate (NTP) to protein was estimated from in vivo 31P-nuclear magnetic resonance relaxation measurements. In aerobic root tips most (approximately 70%) of the NTP is free, whereas under hypoxia NTP appears predominantly bound to protein. Our results indicate that binding of nucleotides to proteins in plant cells will significantly influence levels of free purine nucleotides available to drive and regulate respiration, protein synthesis, ion transport, and other physiological processes.

The role of mesoaccumbens--pallidal circuitry in novelty-induced behavioral activation.

When exposed to an environment for the first time, rats express greater behavioral activation than rats which were previously habituated to that environment. The circuit containing the ventral tegmental area, nucleus accumbens and ventral pallidum is required for the expression of locomotor activity elicited by amphetamine-like psychostimulants. It was hypothesized that this circuit is necessary for the expression of novelty-induced motor activity. Dopamine is a neurotransmitter in the projection from the ventral tegmental area to the nucleus accumbens, while GABA is contained in the projections from the nucleus accumbens to the ventral pallidum and from the ventral pallidum back to the ventral tegmental area. Prior to exposing rats to a novel or habituated environment, they received a microinjection of either saline vehicle or one of the following drugs: fluphenazine (dopamine antagonist) into the nucleus accumbens, muscimol (GABAA agonist) into the ventral pallidum, or baclofen GABAB agonist) into the ventral tegmental area. Each of these pretreatments prevented novelty-induced motor activation without suppressing the activity of habituated animals. In contrast, when these microinjections were made into adjacent motor nuclei of the basal ganglia, including fluphenazine into the striatum, muscimol into the globus pallidus and baclofen into the substantia nigra, they were ineffective in blocking novelty-induced motor activity. These data indicate that the integrity of the circuit that contains the ventral tegmental area, nucleus accumbens and ventral pallidum is required for the manifestation of novelty-induced motor activity.

Cocaine alters glutamic acid decarboxylase differentially in the nucleus accumbens core and shell.

The effects of acute and repeated daily cocaine on the levels of mRNA coding for glutamic acid decarboxylase (GAD), preproenkephalin (PPE), preprotachykinin (PPT), and the dopamine D2 receptor were determined in the striatum, nucleus accumbens core and shell areas (NAcore, NAshell), and medial prefrontal cortex. Rats were given repeated saline or cocaine for 6 days. A cocaine challenge administered 24 h later resulted in an augmented locomotor response in daily cocaine-pretreated rats. Six h after the challenge, rats were sacrificed and Northern blot analysis revealed that acute cocaine increased GAD mRNA levels by 44% in the NAshell, while repeated cocaine prevented the acute cocaine-induced increase. These data suggest that cocaine may differentially regulate GABA release at NA core and shell projection fields.

Behavioral and neurochemical sensitization following cocaine self-administration.

To determine if behavioral and neurochemical sensitization results from cocaine self-administration, rats were trained to self-administer cocaine for 20 consecutive days (26.5 +/- 2.6 mg/kg, IV/day). At 24 h or 21 days after discontinuing cocaine self-administration or yoked saline control, rats were administered an acute injection of saline IP, followed 60 min later by cocaine (15 mg/kg IP). Cocaine-induced changes in motor activity were monitored with a photocell apparatus and alterations in extracellular dopamine in the ventral striatum were measured with microdialysis. There was no difference between treatment groups in the basal level of extracellular dopamine as determined by in vitro calibration. Neither the motor stimulant response nor the increase in extracellular dopamine following an acute cocaine challenge given after 24 h of withdrawal was different between rats which self-administered cocaine and yoked saline controls. However, when the cocaine challenge was given 21 days after discontinuing cocaine self-administration both the motor response and extracellular dopamine content in the ventral straitum were significantly augmented in rats that self-administered cocaine. While no correlation was observed between the average amount of cocaine self-administered each day and the cocaine-induced alterations in extracellular dopamine at either 24 h or 21 days of withdrawl, a significant positive correlation was measured between the increase in photocell counts and the average daily cocaine administration at 21 days of withdrawl. These data show that cocaine self-administration produces an augmentation in the acute behavioral and neurochemical response to a cocaine challenge that resembles the sensitization previously demonstrated with repeated noncontingent administration.

Effects of cocaine microinjections into the nucleus accumbens and medial prefrontal cortex on schedule-induced behaviour: comparison with systemic cocaine administration.

The effects of cocaine HCl infusions into either the nucleus accumbens (NACC) or medial prefrontal cortex (PFC) were compared on the performance of schedule-induced polydipsia (SIP) and related behaviours. Food-deprived rats were exposed to a fixed-time 60-s schedule of food delivery in daily 30-min sessions until stable levels of behaviour were obtained (14 days). Rats were then bilaterally infused with cocaine into either the NACC or PFC via chronically indwelling guide cannulae. Each subject received a sequence of five cocaine infusions (0, 12.5, 25, 50, 100 micrograms) according to a Latin Square design. For comparison, following these intracranial infusions each rat received a sequence of five IP injections of cocaine (0, 2.5, 5, 10, 20 mg/kg) also in a counterbalanced order. NACC and PFC infusions of cocaine and IP cocaine dose-dependently reduced SIP. Cocaine infusions into the NACC, but not the PFC, increased locomotor activity but the characteristic temporal profile of locomotor activity during SIP was retained. IP cocaine also increased locomotor activity in a dose-dependent manner, but the temporal profile of activity was flattened following 20 mg/kg cocaine. NACC and PFC infusions of cocaine had little effect on the total number of panel presses to gain access to the food pellets, but did slightly decrease the high rates of responding immediately prior to the pellet delivery. IP cocaine increased the total number of panel presses at the higher doses, mainly by increasing the low rates of responding. The effects of cocaine infusions into the PFC were behaviourally the most selective, as they reduced SIP without having substantial effects either on locomotor activity or panel pressing.(ABSTRACT TRUNCATED AT 250 WORDS)

Environmental and pharmacological sensitization: effects of repeated administration of systemic or intra-nucleus accumbens cocaine.

The effects of repeated systemic or intra-nucleus accumbens cocaine administration on locomotor activity were examined for environmental dependence. Repeated IP administration of cocaine (15 mg/kg) for 5 days in the context of a given environment increased the locomotor response to a subsequent IP cocaine challenge in that environment. However, there were no differences in the locomotor response to a subsequent IP cocaine challenge in the test chamber in subjects which had received prior repeated IP administration of cocaine in the home-cage. In a second experiment, cocaine (100 micrograms/side) was infused into the nucleus accumbens (NACC) daily for 5 days. This repeated administration produced increases in locomotor activity to subsequent intra-NACC cocaine infusions that were environmentally independent. In contrast to the effects of repeated IP cocaine administration, subjects which received administration of vehicle, acute cocaine, or repeated cocaine in the NACC did not differ following an IP cocaine challenge. The results from these experiments indicate that increases in the response to IP cocaine following repeated IP administration are in part environmentally dependent. Moreover, repeated intra-NACC cocaine infusions increase the responsiveness of the NACC to subsequent intra-NACC cocaine. However, local activation of the NACC alone does not appear to be adequate to produce sensitization to systemically administered cocaine.

Individual differences in behavior following amphetamine, GBR-12909, or apomorphine but not SKF-38393 or quinpirole.

Subjects that respond more to a novel environment show a greater locomotor response to drugs of abuse such as cocaine and amphetamine. The current study was performed to examine differences between high (HR) and low (LR) responding rats to a novel environment following administration of amphetamine, a selective dopamine uptake blocker (GBR-12909), a nonselective dopamine agonist (apomorphine), and selective dopamine D1 and D2/D3 agonists. A behavioral checklist and a rating scale were used to determine the behavioral arousal caused by administration of amphetamine (0, 0.5, 2.0, and 8.0 mg/kg), GBR-12909 (0, 1.25, 5.0, and 20.0 mg/kg), apomorphine (0, 0.1, 0.3, and 1 mg/kg), SKF 39393 (0, 2.5, 10, and 40 mg/kg), or quinpirole (0, 0.05, 0.5, and 5.0 mg/kg). The five drugs produced behavioral activation profiles distinct from each other. Following amphetamine administration, both HR and LR subjects showed dose dependent increases in behavioral arousal. The behaviors primarily affected were sniffing, locomotor activity, rearing, and oral activity. HR rats showed a greater overall behavioral response to amphetamine administration compared with LR rats and there were differences in specific behaviors between the two groups. Following GBR-12909 administration, all subjects showed dose dependent increases in sniffing, locomotor activity, and rearing. Differences between HR and LR were observed in sniffing, locomotor activity, and rearing behaviors. HR and LR both showed dose dependent increases in behavior following apomorphine administration. HR showed greater behavioral activation after apomorphine than LR.(ABSTRACT TRUNCATED AT 250 WORDS)

Individual differences in schedule-induced and conditioned behaviors.

Previous experiments have shown that subjects which exhibit a high locomotor response to novelty (HR) also show a greater locomotor response to psychomotor stimulants than subjects which have a low locomotor response to a novel environment (LR). The current experiments were designed to examine in more detail the behavioral differences between HR and LR rats in non-drug paradigms. In the first experiment HR rats acquired schedule-induced polydipsia (SIP) more readily than LR rats. Panel pressing to gain access to the food pellets, however, was greater in LR rats compared to HR rats, especially after stable levels of SIP had been attained. In the second experiment one group of rats were fed daily after a 30-min period in photocell-cages (food conditioning; FC) while a control group was fed in the home-cage (non-conditioned; NC). FC subjects developed heightened locomotor activity in anticipation of feeding in the initial 30 min in the test-cage compared to NC rats. This anticipatory locomotor activity developed more rapidly and to a greater level in HR rats than in LR rats. The concentrations of dopamine, dihydroxyphenylacetic acid, homovanillic acid, serotonin, 5-hydroxyindoleacetic acid, and norepinephrine were determined at the completion of behavioral testing in both the food conditioned and non-conditioned rats. The food conditioned experiment showed that variations in both the dopaminergic and serotoninergic systems may underlie individual differences in behavioral responsiveness. However, no clear pattern of neurochemical differences emerged. The current set of experiments have demonstrated differences between HR and LR rats in non-drug related paradigms and that HR rats appear to show a greater motivational excitement induced by periodic food delivery than LR rats.

An examination of social typologies in autism.

A system proposed by Wing and coworkers for subtyping autistic individuals on the basis of social interaction is examined in 78 autistic, 39 atypical, and 32 nonautistic, developmentally disordered individuals. Clinical ratings and questionnaire data based on the proposed subtypology were employed. Clinicians were able to reliably group both autistic and nonautistic cases into the three subtypes; these subtypes were strongly related to IQ. Issues relating to the validity and utility of this subtypology are discussed.

The relationship between MRNA levels and the locomotor response to novelty.

Differences in behavioral and neurochemical responses to drugs of abuse and environmental stress have been observed between rats that have a greater locomotor response in a novel environment (high responders: HR) compared to those that have a low response to novelty (low responders: LR). This study examined nuclei associated with the nigrostriatal and mesolimbic systems for differences in mRNA content between HR and LR using Northern blot analysis. These brain regions were chosen because of their role in both drug abuse and stress responses. The mRNAs examined code for either peptide transmitters that interact with the dopaminergic system or components of the dopaminergic system that have not been previously examined for differences between HR and LR. HR rats had approximately 50% lower levels of mRNA for beta-preprotachykinin (PPT) in the core of the nucleus accumbens (NACC) compared to LR. No differences between HR and LR in mRNA levels for dynorphin (DYN), preproenkephalin (PPE), glutamic acid decarboxylase (GAD) or neurotensin (NT) were observed in the core of the NACC. In the shell region of the NACC, HR exhibited a 25% reduction in the level of mRNA for NT compared to LR. No differences between HR and LR in mRNA levels for PPT, DYN, PPE or GAD were observed in the shell of the NACC. In the medial frontal cortex and the dorsal striatum, no differences between HR and LR in mRNA levels for PPT, DYN, PPE, GAD or NT were found. In the substantia nigra and ventral tegmental area no differences between HR and LR in mRNA levels for tyrosine hydroxylase, GAD, cholecystokinin, or NT were noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Individual differences in basal and cocaine-stimulated extracellular dopamine in the nucleus accumbens using quantitative microdialysis.

The current experiment examined the role of nucleus accumbens (NACC) dopamine in individual differences. Subjects were divided into high responders (HR) and low responders (LR) based on their locomotor response to a novel environment. HR rats were subjects which had a locomotor response to novelty in the upper third of the population screened and LR rats in the bottom third of the population. A new method of microdialysis was then used that allowed determination of the extracellular dopamine concentration. This was accomplished by adding various dopamine concentrations (0.0, 5.0 and 20.0 nM) to the perfusate. The concentration of dopamine in the dialysate was subsequently determined. The difference in the dialysate and perfusate dopamine was regressed on the perfusate dopamine. The regression yielded the in vivo recovery and the extracellular concentration. HR rats exhibit a 250% higher basal dopamine concentration (6.45 +/- 1.01 nM, n = 6) than LR rats (2.58 +/- 0.16 nM, n = 7). The in vivo microdialysis recovery was used to estimate the extracellular dopamine following cocaine challenge (15 mg/kg) in the two groups. Following i.p. cocaine administration, HR rats had both a greater locomotor response and increase in absolute dopamine concentration compared to LR rats. The maximum dopamine concentration in the HR group was 23 +/- 2.9 nM, while that in the LR group was only 8.6 +/- 1.1 nM. The maximum in the LR group is comparable to the basal level in the HR group. However, there were no difference in percent change in dopamine following cocaine.(ABSTRACT TRUNCATED AT 250 WORDS)

Drug-induced toxicities associated with high-dose cytosine arabinoside infusions.

The frequency and significance of central nervous system (CNS), ocular, and dermatologic toxicities associated with high-dose cytosine arabinoside (HDARA-C) infusions was evaluated. Patients were selected from one of three Southeastern Cancer Study Group protocols using HDARA-C 2-3 g/m2 body surface area (BSA) and their medical records were reviewed to identify and document the frequency of the toxicities. Those exhibiting CNS toxicity were compared across age, sex, race, previous standard-dose ARA-C or HDARA-C therapy, and infusion rate for toxicity occurrence. Statistical analysis was performed using Fisher's exact test with p less than 0.05. Of the 53 patients evaluated, 37.7% exhibited CNS, 37.7% ocular, and 45.3% dermatologic toxicities. Of the risk factors evaluated, only increasing age and previous ARA-C therapy approached statistical significance. The CNS toxicities associated with HDARA-C are clinically significant since permanent damage may result. Ocular and dermatologic toxicities usually resolve without medical intervention when HDARA-C therapy is discontinued. Further study is necessary to determine appropriate prophylaxis for these toxicities.

Muromonab CD-3: a review of its pharmacology, pharmacokinetics, and clinical use in transplantation.

Muromonab CD-3 (OKT-3) is a monoclonal antibody that is highly effective in the treatment of acute rejection in solid organ transplants. Due to its monoclonal nature, each molecule is identical because it is derived from a single antibody-producing clone. OKT-3 is administered only by intravenous injection and has a harmonic half-life of approximately 18 hours. It binds specifically to the CD-3 complex, which is involved in antigen recognition and cell stimulation, on the surface of T lymphocytes. Immediately after administration CD-3-positive T lymphocytes are abruptly removed from the circulation. The route of metabolism for OKT-3 is not clear; it may be removed by opsonization by the reticuloendothelial system when bound to T lymphocytes, or by human antimurine antibody production. The agent has been effective in reversing corticosteroid-resistant acute rejection in renal, liver, and cardiac transplant recipients. Its use in pancreatic and bone marrow recipients is inconclusive. OKT-3 has a considerable number of initial side effects, and some life-threatening reactions may occur. This drug should not be administered to any patient who is greater than 3% usual body weight because of the potential for the development of severe pulmonary edema. OKT-3 may also be associated with a high rate of infection, especially of the viral type. The usual dose is 5 mg administered as an intravenous bolus over 2-4 minutes daily for 10-14 days. Approximately 85% of patients treated with OKT-3 develop reactive human antimurine antibodies that, over time, may lead to tachyphylaxis and neutralization of the murine antibody OKT-3. OKT-3 is potent immunosuppressive agent and is an important prototype of future monoclonal antibodies.

The pharmacology and neural circuitry of sensitization to psychostimulants.

Behavioral sensitization to amphetamine-like psychostimulants is manifest as a progressive increase in drug-induced anxiety and paranoia which can culminate in psychopathologies, such as paranoid psychosis and panic attacks. Sensitization may also mediate the facilitation of drug relapse in addicts by increasing the reinforcing value of acute drug administration. The primary animal model for psychostimulant-induced psychopathologies involves repeated, non-contingent administration of drug to rodents, which can produce a progressive and enduring augmentation in motor activity and increased susceptibility to drug self-administration. Because of the mature literature implicating mesoaccumbens dopamine transmission in the acute motor and reinforcing effects of amphetamine-like stimulants, investigation into the neural basis of behavioral sensitization has focused on this projection. Over the last decade, with a few exceptions, the neurochemical and molecular literature that has emerged from this effort is replete with inconsistencies. In contrast, the presence of behavioral sensitization is a highly replicable event. It is proposed that behavioral sensitization arises from an alteration in the neural circuitry that subserves the translation of motivationally relevant stimuli into adaptive motor responses. The mesoaccumbens dopamine projection is embedded in this circuit and an enduring change in dopamine transmission may alter the functional state of the circuit to produce behavioral sensitization. However, combinations of alterations in other connections within the circuit can also support behavioral sensitization. The specific changes in the circuit that promote behavioral sensitization are under the control of experimental parameters, such as the drug employed, dosage regimen, withdrawal period and the presence of conditioning cues. Thus, the profile of neurochemical alterations observed after exposure to repeated psychostimulants may vary depending upon the experimental protocol and strain of animals, even though all laboratories report the presence of behavioral sensitization.

Differentiating pervasive developmental disorder not otherwise specified from autism and language disorders.

Features useful in distinguishing children with pervasive developmental disorder (PDD) from those with autism or language disorder were developed from a retrospective chart review using groups of children with PDD-NOS and MA- and sex-matched autistic and language-disordered groups. Charts were reviewed using a list of 80 items compiled from various sources. Items that had adequate interrater reliability and significantly discriminated the PDD-NOS cases from the language-disordered or autistic cases were then evaluated using a second set of cases and signal detection methods. Fewer items significantly discriminated cases with autism from those with PDD-NOS as compared to cases with language disorder. Clinical implications are discussed.

Individual differences in locomotor activity and sensitization.

Male rats were screened for locomotor activity in a novel environment and divided into high (HR) and low (LR) responders based on whether their locomotor activity score for the first hour was above or below the median locomotor activity for the subject sample. Subsequently, the locomotor response to repeated administration of either amphetamine (AMPH; 0.5 mg/kg), cocaine (10 mg/kg), scopolamine (0.5 mg/kg) or saline was monitored in separate groups of HR and LR rats. HR rats had significantly higher overall activity scores than LR rats for all 3 drugs. Both HR and LR rats developed tolerance at the same rate to repeated scopolamine administration. In contrast, only HR rats showed pronounced sensitization to the locomotor stimulating properties of AMPH and a direct correlation was evident between the locomotor response to novelty and the magnitude of sensitization. These results suggest that an individual's response to a novel environment can, to a certain extent, predict drug-induced locomotor activity and that individual differences in the response to novelty and sensitization to AMPH may result from individual variations in a common neural mechanism.