Birth weight and cognition in children with epilepsy

OBJECTIVE

Birth weight is an important indicator of prenatal environment, and subtle variations of birth weight within the normal range have been associated with differential risk for cognitive and behavioral problems. Therefore, we aimed to determine if there are differences in birth weight between full-term children with uncomplicated new/recent-onset epilepsies and typically developing healthy controls. We further examined the relationships between birth weight and childhood/adolescent cognition, behavior, and academic achievement.

METHODS

One hundred eight children with new-onset/recent-onset epilepsy and 70 healthy controls underwent neuropsychological assessment. All participants were born full-term (>37 weeks) without birth complications. Parents were interviewed regarding their child's gestation, birth, and neurodevelopmental history.

RESULTS

Birth weight of children with epilepsy was significantly lower than healthy controls (p = 0.023). Whereas birth weight (covaried with age, sex, handedness, and mother's education) was significantly associated with cognition in controls in multiple domains (intelligence, language, aspects of academic achievement), this relationship was absent in children with epilepsy. Birth weight was not associated with clinical epilepsy variables (age of onset, epilepsy syndrome) and was not predictive of a variety of other academic or psychiatric comorbidities of epilepsy.

SIGNIFICANCE

Although the origin of lower birth weight in children with epilepsy is unknown, these findings raise the possibility that abnormal prenatal environment may affect childhood-onset epilepsy. Furthermore, the positive relationship between birth weight and cognition evident in healthy controls was disrupted in children with epilepsy. However, birth weight was not related to academic and psychiatric comorbidities of childhood epilepsy. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.

Brain morphology in children with epilepsy and ADHD

Background

Attention deficit hyperactivity disorder (ADHD) is a common comorbidity of childhood epilepsy, but the neuroanatomical correlates of ADHD in epilepsy have yet to be comprehensively characterized.

Methods

Children with new and recent-onset epilepsy with (n = 18) and without (n = 36) ADHD, and healthy controls (n = 46) underwent high resolution MRI. Measures of cortical morphology (thickness, area, volume, curvature) and subcortical and cerebellar volumes were compared between the groups using the program FreeSurfer 5.1.

Results

Compared to the control group, children with epilepsy and ADHD exhibited diffuse bilateral thinning in the frontal, parietal and temporal lobes, with volume reductions in the brainstem and subcortical structures (bilateral caudate, left thalamus, right hippocampus). There were very few group differences across measures of cortical volume, area or curvature.

Conclusions

Children with epilepsy and comorbid ADHD exhibited a pattern of bilateral and widespread decreased cortical thickness as well as decreased volume of subcortical structures and brainstem. These anatomic abnormalities were evident early in the course of epilepsy suggesting the presence of antecedent neurodevelopmental changes, the course of which remains to be determined.

Correlation of cognitive function with ultrasound strain indices in carotid plaque

Instability in carotid vulnerable plaque can generate cerebral micro-emboli, which may be related to both stroke and eventual cognitive abnormality. Strain imaging to detect plaque vulnerability based on regions with large strain fluctuations, with arterial pulsation, may be able to determine the risk of cognitive impairment. Plaque instability may be characterized by increased strain variations over a cardiac cycle. Radiofrequency signals for ultrasound strain imaging were acquired from the carotid arteries of 24 human patients using a Siemens Antares with a VFX 13-5 linear array transducer. These patients underwent standardized cognitive assessment (Repeatable Battery for the Assessment of Neuropsychological Status [RBANS]). Plaque regions were segmented by a radiologist at end-diastole using the Medical Imaging Interaction Toolkit. A hierarchical block-matching motion tracking algorithm was used to estimate the cumulated axial, lateral and shear strains within the imaging plane. The maximum, minimum and peak-to-peak strain indices in the plaque computed from the mean cumulated strain over a small region of interest in the plaque with large deformations were obtained. The maximum and peak-to-peak mean cumulated strain indices over the entire plaque region were also computed. All strain indices were then correlated with RBANS Total performance. Overall cognitive performance (RBANS Total) was negatively associated with values of the maximum strain and the peak-to-peak for axial and lateral strains, respectively. There was no significant correlation between the RBANS Total score and shear strain and strain indices averaged over the entire identified plaque for this group of patients. However, correlation of maximum lateral strain was higher for symptomatic patients (r = -0.650, p = 0.006) than for asymptomatic patients (r = -0.115, p = 0.803). On the other hand, correlation of maximum axial strain averaged over the entire plaque region was significantly higher for asymptomatic patients (r = -0.817, p = 0.016) than for symptomatic patients (r = -0.224, p = 0.402). The results reveal a direct relationship between the maximum axial and lateral strain indices in carotid plaque and cognitive impairment.

Patterns of cortical thickness and the Child Behavior Checklist in childhood epilepsy

The purpose of this investigation was to characterize the neuroanatomical correlates (cortical thickness) of variations in parent-reported Child Behavior Checklist (CBCL) scores. Ninety children with epilepsy (aged 8-18) underwent brain MRI, and their parents completed the CBCL. FreeSurfer-derived measures of cortical thickness were examined in relation to the CBCL broad and narrow band competence and behavioral problem scales, as well as the newer DSM-oriented scales. Parent reports of higher (better) social competence skills were associated with increased cortical thickness, especially in frontal regions. Parent reports of behavioral problems were associated with patterns of decreased cortical thickness that varied as a function of the specific behavioral issue under investigation. Congruence of patterns of cortical thinning between the DSM-oriented scales and conceptually related specific problem scales (e.g., ADHD Problems and Attention Problems) was generally weak. The parent-report version of the CBCL is associated with variations in cortical thickness among children with epilepsy. Anatomic abnormalities specific to selected competence and behavioral problem scales can be identified, with more reliable and robust patterns of thinning across scales assessing externalizing behaviors, with generally less prominent findings on scales assessing internalizing behaviors.

Cerebral white matter integrity in children with active versus remitted epilepsy 5 years after diagnosis

INTRODUCTION

Diffusion tensor imaging (DTI) studies have reported white matter abnormalities in childhood-onset epilepsy, but the mechanisms and timing underlying these abnormalities, and their resolution, are not well understood. This study examined white matter integrity in children with active versus remitted epilepsy.

METHODS

Tract-based spatial statistics (TBSS) was used to examine whole-brain DTI indices of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) in 20 children with epilepsy 5-6 years after diagnosis, compared to 29 healthy controls. To determine the status of white matter following cessation of seizures, participants with epilepsy were classified as active versus remitted and comparisons included: (1) controls versus all children with epilepsy, (2) controls versus children with remitted seizures, (3) controls versus children with active seizures, and (4) children with active versus remitted epilepsy.

RESULTS

In the active compared to remitted epilepsy group, significantly higher FA and lower MD, AD and RD values were dispersed in the internal capsule, cingulum, body of the corpus callosum, superior corona radiata and superior fronto-occipital fasciculus. Similar differences were found between the active epilepsy and the control group. There were no significant differences between the remitted epilepsy and control groups.

CONCLUSION

Children with active epilepsy differed in white matter integrity compared to children with remitted epilepsy and healthy controls. It remains to be determined whether these findings represent the outcomes of seizure remission versus an initial biomarker for those children who will ultimately have intractable epilepsy.

The neuropsychological and academic substrate of new/recent-onset epilepsies

OBJECTIVE

To characterize neuropsychological and academic status in children, ages 8-18 years, with new-/recent-onset idiopathic generalized epilepsy (IGE) and idiopathic localization-related epilepsy (ILRE) compared with healthy controls.

STUDY DESIGN

Participants underwent neuropsychological assessment, and parents were interviewed regarding their child's academic history. Cognitive scores for children with epilepsy were age- and sex-adjusted and compared with controls across both broad-band (IGE n = 41 and ILRE n = 53) and narrow-band (childhood/juvenile absence, juvenile myoclonic, benign epilepsy with centro-temporal spikes, and focal [temporal/frontal/not otherwise specified]) syndromes. Academic histories were examined, including problems antecedent to epilepsy onset and diagnosis.

RESULTS

Children with new/recent-onset epilepsies exhibit considerable cognitive abnormality at baseline, including patterns of shared abnormalities across syndromes (eg, psychomotor slowing) as well as unique syndrome-specific cognitive effects (eg, executive function in IGE and language/verbal memory in ILRE) that are observed and sometimes exacerbated in specific IGE and ILRE syndromes. Academic difficulties are evident in approximately 50% of the children with epilepsy, affecting all syndrome groups to an equal degree.

DISCUSSION

Patterns of shared and syndrome-specific cognitive abnormalities and academic problems are present early in the course of virtually all epilepsy syndromes examined here, including syndromes classically viewed as benign. This is the base upon which the effects of recurrent seizures, treatment, and psychosocial effects will be added over time.

Computer-assisted cognitive behavioral therapy for children with epilepsy and anxiety: a pilot study

Anxiety disorders are prevalent in children with epilepsy. The purpose of this study was to evaluate the efficacy, adaptability, and feasibility of a manual-based, computer-assisted cognitive behavioral therapy (CBT) intervention for anxiety disorders in children with epilepsy. Fifteen anxious youth (aged 8-13 years) with epilepsy completed 12 weeks of manualized computer-assisted CBT. The children and parents completed a semi-structured interview at baseline, and questionnaires assessing symptoms of anxiety, depression, and behavior problems were completed prior to treatment, at treatment midpoint, after treatment completion, and at three months posttreatment. There were significant reductions in the symptoms of anxiety and depression reported by the children at completion of the intervention and at the three-month follow-up. Similarly, the parents reported fewer symptoms of anxiety and a reduction in behavior problems. No adverse events were reported. This CBT intervention for children with epilepsy and anxiety disorders appears to be safe, effective, and feasible and should be incorporated into future intervention studies.

Is lower IQ in children with epilepsy due to lower parental IQ? A controlled comparison study

AIM

The aim of this study was to determine the relationship between parent and child Full-scale IQ (FSIQ) in children with epilepsy and in typically developing comparison children and to examine parent-child IQ differences by epilepsy characteristics.

METHOD

The study participants were 97 children (50 males, 47 females; age range 8-18y; mean age 12y 3mo, SD 3y1mo) with recent-onset epilepsy including idiopathic generalized (n=43) and idiopathic localization-related epilepsies (n=54); 69 healthy comparison children (38 females, 31 males; age range 8-18y; mean age 12y 8mo, SD 3y 2mo), and one biological parent per child. All participants were administered the Wechsler Abbreviated Scale of Intelligence (WASI). FSIQ was compared in children with epilepsy and typically developing children; FSIQ was compared in the parents of typically developing children and the parents of participants with epilepsy; parent-child FSIQ differences were compared between the groups.

RESULTS

FSIQ was lower in children with epilepsy than in comparison children (p<0.001). FSIQ of parents of children with epilepsy did not differ from the FSIQ of the parents of typically developing children. Children with epilepsy had significantly lower FSIQ than their parents (p<0.001), whereas comparison children did not. The parent-child IQ difference was significantly higher in the group with epilepsy than the comparison group (p=0.043). Epilepsy characteristics were not related to parent-child IQ difference.

INTERPRETATION

Parent-child IQ difference appears to be a marker of epilepsy impact independent of familial IQ, epilepsy syndrome, and clinical seizure features. This marker is evident early in the course of idiopathic epilepsies and can be tracked over time.

Ventricular enlargement in new-onset pediatric epilepsies

PURPOSE

To examine baseline and prospective (2-year) changes in third, fourth, and lateral ventricle volumes in children with new-onset idiopathic epilepsies and controls (age 8-18 years).

METHODS

Structural magnetic resonance imaging (MRI) were collected from children with idiopathic generalized epilepsy (IGE, n = 29), idiopathic localization-related epilepsy (ILRE, n = 30), and healthy controls (HCs, n = 49). Volumes of the third, fourth, and lateral ventricles were derived and compared across groups, followed by shape analyses, to identify specific regions of ventricular abnormality. Of the initial cohort, a consecutive sample of 71 children returned 2 years later for reimaging and determination of progressive changes in the ventricular system.

KEY FINDINGS

At baseline, children with new-onset IGE had significantly larger lateral and third ventricle volumes relative to the HC group. In addition, lateral ventricle enlargement in IGE was significantly greater compared to new-onset ILRE. Shape analysis of the lateral ventricles revealed that volume expansion in IGE was selective for the anterior horn, a region surrounded by the lateral and medial frontal lobes as well as basal ganglia. These abnormalities did not progress over a 2-year interval.

SIGNIFICANCE

Abnormalities in brain development prior to onset and diagnosis of epilepsy are evident and reflected in expansion of the ventricular system, especially among children with IGE. These abnormalities appear to represent an antecedent and possibly static finding given the lack of progressive ventricular expansion over the 2-year interval following diagnosis and treatment.

Density-independent growth of floodplain river channel catfish Ictalurus punctatus

This study investigated the relative influence of biotic and abiotic factors on the growth of channel catfish Ictalurus punctatus in seven Mississippi floodplain rivers. The results indicate that growth was density-independent, being defined largely by abiotic conditions.

Test-retest reliability of voluntary emotion regulation

Despite growing interest in emotion regulation, the degree to which psychophysiological measures of emotion regulation are stable over time remains unknown. We examined four-week test-retest reliability of corrugator electromyographic and eyeblink startle measures of negative emotion and its regulation. Both measures demonstrated similar sensitivity to the emotion manipulation, but only individual differences in corrugator modulation and regulation showed adequate reliability. Startle demonstrated diminished sensitivity to the regulation instructions across assessments and poor reliability. This suggests that corrugator represents a trait-like measure of voluntary emotion regulation, whereas startle should be used with caution for assessing individual differences. The data also suggest that corrugator and startle might index partially dissociable constructs and underscore the need to collect multiple measures of emotion.

Local methylthiolate adsorption geometry on Au(111) from photoemission core-level shifts

The local adsorption structure of methylthiolate in the ordered Au(111)-(sqrt[3]xsqrt[3])R30 degrees phase has been investigated using core-level-shift measurements of the surface and bulk components of the Au 4f(7/2) photoelectron binding energy. The amplitude ratio of the core-level-shift components associated with surface Au atoms that are, and are not, bonded to the thiolate is found to be compatible only with the previously proposed Au-adatom-monothiolate moiety in which the thiolate is bonded atop Au adatoms in hollow sites, and not on an unreconstructed surface, or in Au-adatom-dithiolate species.

Human dendritic cells pulsed with specific lipopeptides stimulate autologous antigen-specific T cells without the addition of exogenous maturation factors

Serum-free culture conditions to generate immature human monocyte-derived DC (Mo-DC) were optimized, and the parameters that influence their maturation after exposure to lipopeptides containing CD4(+) and CD8(+) T-cell epitopes were examined. The lipopeptides contained a single CD4(+) helper T-cell epitopes, one of a number of human leucocyte antigen (HLA)-A2-restricted cytotoxic T-cell epitope and the lipid Pam2Cys. To ensure complete maturation of the Mo-DC, we examined (i) the optimal lipopeptide concentration, (ii) the optimal Mo-DC density and (iii) the appropriate period of exposure of the Mo-DC to the lipopeptides. The results showed that a high dose of lipopeptide (30 microm) was no more efficient at upregulating maturation markers on Mo-DC than a low dose (6 microm). There was an inverse relationship between Mo-DC concentration and the mean fluorescence intensity of maturation markers. In addition, at the higher cell concentrations, the chemotactic capacity of the Mo-DC towards a cognate ligand, CCL21, was reduced. Thus, high cell concentrations during lipopeptide exposure were detrimental to Mo-DC maturation and function. The duration of exposure of Mo-DC to the lipopeptides had little effect on phenotype, although Mo-DC exposed to lipopeptides for 48 rather than 4 h showed an increased ability to stimulate autologous peripheral blood mononuclear cells to release interferon-gamma in the absence of exogenous maturation factors. These findings reveal conditions for generating mature antigen-loaded DC suitable for targeted immunotherapy.

Effects of electrode density and electrolyte spreading in dense array electroencephalographic recording

OBJECTIVE

High-density EEG recording offers increased spatial resolution but requires careful consideration of how the density of electrodes affects the potentials being measured. Power differences as a function of electrode density and electrolyte spreading were examined and a method for correcting these differences was tested.

METHODS

Separate EEG recordings from 8 participants were made using a high-density electrode net, first with 6 of 128 electrodes active followed by recordings with all electrodes active. For a subset of 4 participants measurements were counterbalanced with recordings made in the reversed order by drying the hair after the high-density recordings and using a fresh dry electrode net of the same size for the low-density recordings. Mean power values over 6 resting eyes open/closed EEG recordings at the 6 active electrodes common to both recording conditions were compared. Evidence for possible electrolyte spreading or bridging between electrodes was acquired by computing Hjorth electrical distances. Spherical spline interpolation was tested for correcting power values at electrodes affected by electrolyte spreading for these participants and for a subset of participants from a larger previous study.

RESULTS

For both the complete set and the counterbalanced subset, significant decreases in power at the 6 common electrodes for the high-density recordings were observed across the range of the standard EEG bands (1-44 Hz). The number of bridges or amount of electrolyte spreading towards the reference electrode as evidenced by small Hjorth electrical distances served as a predictor of this power decrease. Spherical spline interpolation increased the power values at electrodes affected by electrolyte spreading and by a significant amount for the larger number of participants in the second group.

CONCLUSIONS

Understanding signal effects caused by closely spaced electrodes, detecting electrolyte spreading and correcting its effects are important considerations for high-density EEG recordings. A combination of scalp maps of power density and plots of small Hjorth electrical distances can be used to identify electrodes affected by electrolyte spreading. Interpolation using spherical splines offers a method for correcting the potentials measured at these electrodes.

Molecular and genetic characterisation of the host-protective oncosphere antigens of taeniid cestode parasites

Highly effective recombinant vaccines have been developed against Taenia ovis infection in sheep, Taenia saginata infection in cattle, Taenia solium infection in pigs, Echinococcus granulosus and Echinococcus multilocularis infections in a variety of intermediate host species. These vaccines have been based on the identification and expression in Escherichia coli of antigens derived from the oncosphere life cycle stage, contained within the parasites' eggs. Investigation of the molecular aspects of these proteins and the genes encoding them have revealed a number of common features, including the presence of a predicted secretory signal sequence, and one or two copies of a fibronectin type III domain, each encoded by separate exons within the associated gene. Evidence has been obtained to confirm glycosylation of some of these antigens. Ongoing investigations will shed light on the biological roles played by the proteins within the parasites and the mechanism by which they make the parasites vulnerable to vaccine-induced immune responses.

Affective style and in vivo immune response: neurobehavioral mechanisms

Considerable evidence exists to support an association between psychological states and immune function. However, the mechanisms by which such states are instantiated in the brain and influence the immune system are poorly understood. The present study investigated relations among physiological measures of affective style, psychological well being, and immune function. Negative and positive affect were elicited by using an autobiographical writing task. Electroencephalography and affect-modulated eye-blink startle were used to measure trait and state negative affect. Participants were vaccinated for influenza, and antibody titers after the vaccine were assayed to provide an in vivo measure of immune function. Higher levels of right-prefrontal electroencephalographic activation and greater magnitude of the startle reflex reliably predicted poorer immune response. These data support the hypothesis that individuals characterized by a more negative affective style mount a weaker immune response and therefore may be at greater risk for illness than those with a more positive affective style.

Hibernation in freshwater turtles: softshell turtles (Apalone spinifera) are the most intolerant of anoxia among North American species

Softshell turtles (Apalone spinifera) were submerged at 3 degrees C in anoxic or normoxic water. Periodically, blood PO(2), PCO(2), pH, plasma [Cl(-)], [Na(+)], [K(+)], total Ca, total Mg, lactate, glucose, and osmolality were measured; hematocrit and body mass determined; and blood [HCO(3)(-)] calculated. On day 14 of anoxic submergence, five of eight softshell turtles were dead, one died immediately after removal, and the remaining two showed no signs of life other than a heartbeat. After 11 days of submergence in anoxic water, blood pH fell from 7.923 to 7.281 and lactate increased to 62.1 mM. Plasma [HCO(3)(-)] was titrated from 34.57 mM to 4.53 mM. Plasma [Cl(-)] fell, but [K(+)] and total Ca and Mg increased. In normoxic submergence, turtles survived over 150 days and no lactate accumulated. A respiratory alkalosis developed (pH-8.195, PCO(2)-5.49 after 10 days) early and persisted throughout; no other variables changed in normoxic submergence. Softshell turtles are very capable of extrapulmonary extraction of O(2), but are an anoxia-intolerant species of turtle forcing them to utilize hibernacula that are unlikely to become hypoxic or anoxic (e.g., large lakes and rivers).

Frontal brain asymmetry in restrained eaters

It is well known that the eating patterns that restrain chronic dieters (restrained eaters) can be disinhibited by anxiety, which in turn has been associated with relative right frontal brain activity in independent electroencephalographic (EEG) studies. Combining these two lines of evidence, the authors tested the hypothesis that chronic restrained eating is associated with relative right frontal asymmetry. Resting anterior brain asymmetry and self-reported measures of anxiety and depression were collected in 23 restrained and 32 unrestrained eaters. As hypothesized, groups differed in tonic frontal activity, with restrained eaters showing more relative right frontal activity. Furthermore, relative right frontal activity was associated with greater self-reported restraint. Right-sided prefrontal asymmetry may thus represent a diathesis associated with increased vulnerability toward restrained eating.

Frontal brain asymmetry in restrained eaters

It is well known that the eating patterns that restrain chronic dieters (restrained eaters) can be disinhibited by anxiety, which in turn has been associated with relative right frontal brain activity in independent electroencephalographic (EEG) studies. Combining these two lines of evidence, the authors tested the hypothesis that chronic restrained eating is associated with relative right frontal asymmetry. Resting anterior brain asymmetry and self-reported measures of anxiety and depression were collected in 23 restrained and 32 unrestrained eaters. As hypothesized, groups differed in tonic frontal activity, with restrained eaters showing more relative right frontal activity. Furthermore, relative right frontal activity was associated with greater self-reported restraint. Right-sided prefrontal asymmetry may thus represent a diathesis associated with increased vulnerability toward restrained eating.

Synthetic peptide epitope-based polymers: controlling size and determining the efficiency of epitope incorporation

The assembly of synthetic peptide-based vaccines that incorporate multiple epitopes is a major goal of vaccine development, because such vaccines will potentially allow the immunization of outbred populations against a number of different pathogens. We have shown that free radical-induced polymerization of individual peptide epitopes results in the incorporation of multiple copies of the same or different epitopes into high molecular weight immunogens (O'Brien-Simpson, N.M., Ede, N.J., Brown, L.E., Swan, J. & Jackson, D.C. (1997) Polymerization of unprotected synthetic peptides: a view toward synthetic peptide vaccines. J. Am. Chem. Soc.119, 1183-1188; Jackson, D.C., O'Brien-Simpson, N., Ede, N.J. & Brown, L.E. (1997) Free radical induced polymerization of synthetic peptides into polymeric immunogens. Vaccine 15, 1697-1705). The ability to control the size of these polymers, to determine the physical and chemical properties of the backbone material and also to know the extent to which individual peptide epitopes are incorporated are important manufacturing considerations and form the subject of this study. We show here that the polymerization process is highly efficient with at least 70% of peptides incorporated into the resulting polymer, that acrylamide and acryloylated amino acids can be used as comonomers with peptide epitopes in the polymerization reaction and that the choice of the comonomer can influence the properties of the resulting polymer. We also show that the size of chain growth polymers is restricted in the presence of chain transfer agents, that the resulting polymer size can be predicted and that there is little or no difference in the immunogenicity of polymers that range in apparent molecular size between 18 kDa and 335 kDa. The successful polymerization of peptide epitopes with an acryloyl-amino acid creates the potential for introducing different physical and chemical properties into artificial protein immunogens.

Modulation of amygdalar activity by the conscious regulation of negative emotion

Lesion and neuroimaging studies suggest the amygdala is important in the perception and production of negative emotion; however, the effects of emotion regulation on the amygdalar response to negative stimuli remain unknown. Using event-related fMRI, we tested the hypothesis that voluntary modulation of negative emotion is associated with changes in neural activity within the amygdala. Negative and neutral pictures were presented with instructions to either "maintain" the emotional response or "passively view" the picture without regulating the emotion. Each picture presentation was followed by a delay, after which subjects indicated how they currently felt via a response keypad. Consistent with previous reports, greater signal change was observed in the amygdala during the presentation of negative compared to neutral pictures. No significant effect of instruction was found during the picture presentation component of the trial. However, a prolonged increase in signal change was observed in the amygdala when subjects maintained the negative emotional response during the delay following negative picture offset. This increase in amygdalar signal due to the active maintenance of negative emotion was significantly correlated with subjects' self-reported dispositional levels of negative affect. These results suggest that consciously evoked cognitive mechanisms that alter the emotional response of the subject operate, at least in part, by altering the degree of neural activity within the amygdala.

The central role played by peptides in the immune response and the design of peptide-based vaccines against infectious diseases and cancer

Vaccines are one of the most cost effective methods of improving public health thereby increasing the quality of life. Prophylactic and therapeutic treatment by vaccines can prevent infectious diseases and some cancers and could also be used in the treatment of autoimmune disorders. An appreciation of this potential has resulted in a burgeoning literature which not only describes the scientific efforts being made into designing new and improved vaccines but also drives the efforts being made by public health organizations world-wide in delivering vaccines to the community. At the forefront of technologies being applied to the design of vaccines is the use of synthetic peptides; the chemical technologies used to assemble peptides have made great strides over the last decade and assembly of hi-fidelity peptides which can be of high molecular weight, multimeric or even branched is now almost routine. Together with the advances in peptide technology our understanding of the molecular events that are necessary to induce immune responses has also made great strides. The central role that peptides play in immune recognition is now recognised and rules are emerging that are being applied to the construction of peptide-based vaccines that, in the right context, can induce humoral (antibody) and cellular (cytotoxic and helper T cell) immune responses. Synthetic peptides are exquisitely placed to answer questions about immune recognition and along the way to provide us with new and improved vaccines.

Identification of canine helper T-cell epitopes from the fusion protein of canine distemper virus

The fusion protein of canine distemper virus (CDV-F), a 662 amino-acid envelope protein, was used as the target molecule for identification of canine T helper (Th) epitopes. A library of 94 peptides, each 17 residues in length overlapping by 10 residues and covering the entire sequence of CDV-F, was screened using a lymphocyte proliferation assay with peripheral blood mononuclear cells (PBMC) obtained from dogs inoculated with canine distemper virus (CDV) vaccine. Initially we observed low and inconsistent proliferation of PBMC in response to these peptides, even when using cells obtained from dogs that had received multiple doses of CDV. Subsequently, the use of expanded cell populations derived by in vitro stimulation of canine PBMC with pools of peptides allowed the identification of a number of putative canine Th-epitopes within the protein sequence of CDV-F. There were two major clusters of Th-epitopes identified close to the cleavage site of the F0 fusion protein, while some others were scattered in both the F1 and F2 fragments of the protein. Some of these peptides, in particular peptide 35 (p35), were stimulatory in dogs of different breeds and ages. The identification of such promiscuous canine Th-epitopes encouraged us to assemble p35 in tandem with luteinising hormone releasing hormone (LHRH) a 10 amino-acid residue synthetic peptide representing a B-cell epitope which alone induces no antibody in dogs. The totally synthetic immunogen was able to induce the production of very high titres of antibodies against LHRH in all dogs tested. These results indicate that p35 could be an ideal candidate for use as a Th-epitope for use in outbred dogs.

The physiology of hibernation in common map turtles (Graptemys geographica)

Map turtles from Wisconsin were submerged at 3 degrees C in normoxic and anoxic water to simulate extremes of potential respiratory microenvironments while hibernating under ice. In predive turtles, and in turtles submerged for up to 150 days, plasma PO2, PCO2) pH, [Cl-], [Na+], [K+], total Mg, total Ca, lactate, glucose, and osmolality were measured; hematocrit and body mass were determined, and plasma [HCO3-] was calculated. Turtles in anoxic water developed a severe metabolic acidosis, accumulating lactate from a predive value of 1.7 to 116 mmol/l at 50 days, associated with a fall in pH from 8.010 to 7.128. To buffer lactate increase, total calcium and magnesium rose from 3.5 and 2.0 to 25.7 and 7.6 mmol/l, respectively. Plasma [HCO3-] was titrated from 44.7 to 4.3 mmol/l in turtles in anoxic water. Turtles in normoxic water had only minor disturbances of their acid-base status and ionic statuses; there was a marked increase in hematocrit from 31.1 to 51.9%. This study and field studies suggest that map turtles have an obligatory requirement for a hibernaculum that provides well-oxygenated water (e.g. rivers and large lakes rather than small ponds and swamps) and that this requirement is a major factor in determining their microdistribution.