In Silico Models of DNA Damage and Repair in Proton Treatment Planning: A Proof of Concept

There is strong in vitro cell survival evidence that the relative biological effectiveness (RBE) of protons is variable, with dependence on factors such as linear energy transfer (LET) and dose. This is coupled with the growing in vivo evidence, from post-treatment image change analysis, of a variable RBE. Despite this, a constant RBE of 1.1 is still applied as a standard in proton therapy. However, there is a building clinical interest in incorporating a variable RBE. Recently, correlations summarising Monte Carlo-based mechanistic models of DNA damage and repair with absorbed dose and LET have been published as the Manchester mechanistic (MM) model. These correlations offer an alternative path to variable RBE compared to the more standard phenomenological models. In this proof of concept work, these correlations have been extended to acquire RBE-weighted dose distributions and calculated, along with other RBE models, on a treatment plan. The phenomenological and mechanistic models for RBE have been shown to produce comparable results with some differences in magnitude and relative distribution. The mechanistic model found a large RBE for misrepair, which phenomenological models are unable to do. The potential of the MM model to predict multiple endpoints presents a clear advantage over phenomenological models.

Clinical and biomarker profiling of prodromal Alzheimer's disease in workpackage 5 of the Innovative Medicines Initiative PharmaCog project: a 'European ADNI study'

BACKGROUND

In the field of Alzheimer's disease (AD), the validation of biomarkers for early AD diagnosis and for use as a surrogate outcome in AD clinical trials is of considerable research interest.

OBJECTIVE

To characterize the clinical profile and genetic, neuroimaging and neurophysiological biomarkers of prodromal AD in amnestic mild cognitive impairment (aMCI) patients enrolled in the IMI WP5 PharmaCog (also referred to as the European ADNI study).

METHODS

A total of 147 aMCI patients were enrolled in 13 European memory clinics. Patients underwent clinical and neuropsychological evaluation, magnetic resonance imaging (MRI), electroencephalography (EEG) and lumbar puncture to assess the levels of amyloid β peptide 1-42 (Aβ42), tau and p-tau, and blood samples were collected. Genetic (APOE), neuroimaging (3T morphometry and diffusion MRI) and EEG (with resting-state and auditory oddball event-related potential (AO-ERP) paradigm) biomarkers were evaluated.

RESULTS

Prodromal AD was found in 55 aMCI patients defined by low Aβ42 in the cerebrospinal fluid (Aβ positive). Compared to the aMCI group with high Aβ42 levels (Aβ negative), Aβ positive patients showed poorer visual (P = 0.001), spatial recognition (P < 0.0005) and working (P = 0.024) memory, as well as a higher frequency of APOE4 (P < 0.0005), lower hippocampal volume (P = 0.04), reduced thickness of the parietal cortex (P < 0.009) and structural connectivity of the corpus callosum (P < 0.05), higher amplitude of delta rhythms at rest (P = 0.03) and lower amplitude of posterior cingulate sources of AO-ERP (P = 0.03).

CONCLUSION

These results suggest that, in aMCI patients, prodromal AD is characterized by a distinctive cognitive profile and genetic, neuroimaging and neurophysiological biomarkers. Longitudinal assessment will help to identify the role of these biomarkers in AD progression.

Evaluation of symptomatic drug effects in Alzheimer's disease: strategies for prediction of efficacy in humans

In chronic diseases such as Alzheimer's disease (AD), the arsenal of biomarkers available to determine the effectiveness of symptomatic treatment is very limited. Interpretation of the results provided in literature is cumbersome and it becomes difficult to predict their standardization to a larger patient population. Indeed, cognitive assessment alone does not appear to have sufficient predictive value of drug efficacy in early clinical development of AD treatment. In recent years, research has contributed to the emergence of new tools to assess brain activity relying on innovative technologies of imaging and electrophysiology. However, the relevance of the use of these newer markers in treatment response assessment is waiting for validation. This review shows how the early clinical assessment of symptomatic drugs could benefit from the inclusion of suitable pharmacodynamic markers. This review also emphasizes the importance of re-evaluating a step-by-step strategy in drug development.

F-spondin gene transfer improves memory performance and reduces amyloid-β levels in mice

Alzheimer's disease (AD) is the most prevalent form of dementia affecting the elderly. Evidence has emerged signifying that stimulation of the reelin pathway should promote neural plasticity and suppress molecular changes associated with AD, suggesting a potential therapeutic application to the disease. This was explored through the use of lentiviral vector-mediated overexpression of the reelin homolog, F-spondin, which is an activator of the reelin pathway. Intrahippocampal gene transfer of F-spondin improved spatial learning/memory in the Morris Water Maze and increased exploration of the novel object in the Novel Object Recognition test in wild-type mice. F-spondin overexpression also suppressed endogenous levels of amyloid beta (Aβ(42)) in these mice and reduced Aβ plaque deposition while improving synaptophysin expression in transgenic mouse models of AD. These data demonstrate pathologic and cognitive improvements in mice through F-spondin overexpression.

Effects of dietary resveratrol on the sleep-wake cycle in the non-human primate gray mouse lemur (Microcebus murinus)

Converging evidence shows that the non-human primate gray mouse lemur (Microcebus murinus) is ideal for the study of the aging process and for testing the effects of new therapies and dietary interventions on age-associated pathologies. One such dietary supplement is resveratrol (RSV), a dietary polyphenolic compound with several positive effects on metabolic functions and longevity. However, little is known about the effect of RSV on the lemur sleep-wake cycle, which reflects mammalian brain function and health. In the present study, the authors investigated this effect by comparing sleep-wake cycles in adult lemurs based on electroencephalographic (EEG) rhythms. The effect of short-term RSV supplementation on the sleep-wake cycle of mouse lemurs was evaluated in entrained conditions (long-day photoperiods, light:dark 14:10). After 3 wks of RSV supplementation, the animals exhibited a significantly increased proportion of active-wake time, occurring mainly during the resting phase of the sleep-wake cycle (+163%). The increase in active-wake time with RSV supplementation was accompanied by a significant reduction of both paradoxical sleep (-95%) and slow-wave sleep (-38%). These changes mainly occurred during the resting phase of the sleep-wake cycle (RSV supplementation induced negligible changes in active-wake time during the active phase of the sleep-wake cycle). The present data suggest that RSV may be a potent regulator of sleep-wake rhythms and could be of major interest in the study of sleep perturbations associated with aging and neuropathology.

Characterisation of amyloid-induced inflammatory responses in the rat retina

Amyloid-induced inflammation is thought to play a critical and early role in the pathophysiology of Alzheimer's disease. As such, robust models with relevant and accessible compartments that provide a means of assessing anti-inflammatory agents are essential for the development of therapeutic agents. In the present work, we have characterised the induction of inflammation in the rat retina following intravitreal administration of amyloid-beta protein (Aβ). Histology and mRNA endpoints in the retina demonstrate Aβ1-42-, but not Aβ42-1-, induced inflammatory responses characterised by increases in markers for microglia and astrocytes (ionised calcium-binding adaptor molecule 1 (iba-1), GFAP and nestin) and increases in mRNA for inflammatory cytokines and chemokines such as IL1-β, MIP1α and TNFα. Likewise, analysis of vitreal cytokines also revealed increases in inflammatory cytokines and chemokines, including IL1-β, MIP1α and MCP1, induced by Aβ1-42 but not Aβ42-1. This profile of pro-inflammatory gene and protein expression is consistent with that observed in the Alzheimer's disease brain and suggest that this preclinical model may provide a useful relevant tool in the development of anti-inflammatory approaches directed towards Alzheimer's disease therapy.

Inflammatory risk factors and pathologies associated with Alzheimer's disease

The importance of inflammatory processes in Alzheimer's disease (AD) progression has been confirmed during the past decade by the intensive investigation of inflammatory mediators in the brain of AD patients as well as by the genetic and drug manipulation of animal models of AD. Imaging studies have revealed that the activation of microglia occurs in early stages of the disease, even before plaque and tangle formation, and is correlated with early cognitive deficits. In this review, we analyze how different risk factors, such as trauma, stroke, infection, and metabolic diseases can lead to an acceleration of the inflammatory response in the AD brain and to an increased risk of developing this disorder. The use of imaging techniques for early detection of glial activation which offer the advantage of investigating how potential anti-inflammatory therapies may influence disease progression and levels of cognition is also discussed.

Alginate reduces the increased uptake of cholesterol and glucose in overweight male subjects: a pilot study

Dietary fibers are of particular interest in the prevention and management of obesity and consequent pathologies. Among the proposed mechanisms of action of fiber is the modulation of nutrient uptake from the small intestine. We have used a crossover study design in human subjects to monitor the uptake of glucose, cholesterol, and triacylglycerols in human subjects with normal and high body mass index. Our data demonstrate that uptakes of glucose, triacylglycerols, and cholesterol are all increased with increasing body fat. We demonstrate that treatment with a 1.5-g dose of a strong-gelling alginate may restore uptake of cholesterol and glucose to the levels of healthy subjects. These data indicate a potential therapeutic application of gelling fibers.

The pathology of APP transgenic mice: a model of Alzheimer's disease or simply overexpression of APP?

Alzheimer's disease (AD) is characterized by a number of pathological features, notably extracellular senile plaques composed of the beta-amyloid protein (Abeta) and neurofibrillary tangles (NFT's), which are intracellular inclusions of hyperphosphorylated tau protein. In their attempts to generate a model of AD, many laboratories have produced transgenic mice that overexpress the amyloid precursor protein (APP), in particular, mutant APP which is associated with familial forms of AD in man. Histopathological assessment shows that APP transgenic mice demonstrate an accumulation of Abeta in plaques from an early age; these plaques are invariably surrounded by activated inflammatory cells such as astrocytes and microglia, as is common in AD brain. Also, commonly associated with the plaques is hyperphosphorylated tau, although this does not take on the NFT phenotype observed in AD. Atrophy and neurodegenerative pathology are other common features of AD; some neuronal loss is evident in close proximity to plaques in APP transgenic mice although this is not extensive. Consequently, it is evident that APP transgenic mice exhibit, to some degree, many of the pathological features of AD.

Daily ingestion of alginate reduces energy intake in free-living subjects

Sodium alginate is a seaweed-derived fibre that has previously been shown to moderate appetite in models of acute feeding. The mechanisms underlying this effect may include slowed gastric clearance and attenuated uptake from the small intestine. In order to assess whether alginate could be effective as a means of appetite control in free-living adults, 68 males and females (BMI range: 18.50-32.81 kg/m(2)) completed this randomised, controlled two-way crossover intervention to compare the effects of 7 day daily ingestion of a strong-gelling sodium alginate formulation against a control. A sodium alginate with a high-guluronate content was chosen because, upon ingestion, it forms a strong gel in the presence of calcium ions. Daily preprandial ingestion of the sodium alginate formulation produced a significant 134.8 kcal (7%) reduction in mean daily energy intake. This reduced energy intake was underwritten by significant reductions in mean daily carbohydrate, sugar, fat, saturated fat and protein intakes. The absence of any significant interaction effects between the main effect of preload type and those of gender, BMI classification and/or timing of preload delivery indicates the efficacy of this treatment for individuals in different settings. These findings suggest a possible role for a strong-gelling sodium alginate formulation in the future management of overweight and obesity.

Abeta deposition and related pathology in an APP x PS1 transgenic mouse model of Alzheimer's disease

A transgenic mouse bearing mutant transgenes linked to familial forms of Alzheimer's disease (AD) for the amyloid precursor protein and presenilin-1 (TASTPM) showed Abeta plaque deposition and age-related histological changes in associated brain pathology. The Abeta present was of multiple forms, including species with a C-terminus at position 40 or 42, as well as an N-terminus at position 1 or truncated in a pyro-3-glutamate form. Endogenous rodent Abeta was also present in the deposits. Laser capture microdissection extracts showed that multimeric forms of Abeta were present in both plaque and tissue surrounding plaques. Associated with the Abeta deposits was evidence of an inflammatory response characterised by the presence of astrocytes. Also present in close association with the deposits was phosphorylated tau and cathepsin D immunolabelling. The incidence of astrocytes and of phosphorylated tau and cathepsin D load showed that both of these potential disease markers increased in parallel to the age of the mice and with Abeta deposition. Immunohistochemical labelling of neurons in the cortex and hippocampus of TASTPM mice suggested that the areas of Abeta deposition were associated with the loss of neurons. TASTPM mice, therefore, exhibit a number of the pathological characteristics of disease progression in AD and may provide a means for assessment of novel therapeutic agents directed towards modifying or halting disease progression.

Transgenic mice over-expressing human beta-amyloid have functional nicotinic alpha 7 receptors

A potentially major factor in the development of Alzheimer's disease is the enhanced production of soluble beta-amyloid peptide fragments amyloid beta peptide(1-40) and amyloid beta peptide(1-42). These amyloid peptides are generated by cleavage of the amyloid-precursor protein and aggregate spontaneously to form amyloid plaques, which are a classical pathological hallmark in Alzheimer's disease. Although the precise mechanisms are unknown, it is widely believed that amyloid peptides initiate the degenerative process, resulting in subsequent cognitive decline. One interaction of amyloid beta peptide that may contribute to an impairment of cognition is its high affinity binding to the alpha 7 nicotinic receptor; a receptor shown to be important for cognition in a number of studies. There is some controversy, however, whether amyloid beta peptide inhibits or activates this receptor. We have cloned and stably expressed the human alpha 7 receptor and investigated its interaction with amyloid beta peptide using patch clamp electrophysiology. Human alpha 7 was activated in a concentration-dependent fashion by nicotine, acetylcholine and choline and potently inhibited by methyllycaconitine citrate. The responses were inwardly rectifying and exhibited rapid activation, desensitization and deactivation. Amyloid beta peptide(1-42) antagonized human alpha7 responses in a partially reversible fashion; no agonist effects of amyloid beta peptide(1-42) were detected. A similar inhibition of mouse alpha 7 was also observed. In addition, we have assessed the function of native alpha 7 receptors in hippocampal slices prepared from transgenic mice that over-express human amyloid. Despite this clear inhibition of recombinant receptors, hippocampal GABAergic interneurones in slices from beta-amyloid over-expressing mice still possess alpha 7 receptor-mediated currents.

Modulation of hippocampal excitability by 5-HT4 receptor agonists persists in a transgenic model of Alzheimer's disease

5-HT(4) receptors are widely distributed in both peripheral and central nervous systems where they couple, via a G-protein, to the activation of adenylate cyclase. In the brain, the highest 5-HT(4) receptor densities are found in the limbic system, including the hippocampus and frontal cortex. It has been suggested that activation of these receptors may be of therapeutic benefit in diseases that produce cognitive deficits such as Alzheimer's disease (AD). Previous electrophysiological studies have shown that the 5-HT(4) agonist, Zacopride, can increase population spike amplitude recorded in region CA1 of rat hippocampal slices in a cyclic AMP (cAMP)/cAMP-dependent protein kinase A-dependent manner. We report here that the 5-HT(4) agonist, Prucalopride, and the 5-HT(4) partial agonist, SL65.0155, produce a similar effect in rat hippocampal slices and that the specific 5-HT(4) antagonist, GR113808, blocks these effects. To investigate the potential use of 5-HT(4) agonists in the treatment of AD, Prucalopride was applied to hippocampal slices from a transgenic mouse line that overexpresses the Abeta peptide. Despite the deficit in synaptic transmission present in these mice, the percentage increase of the CA1 population spike induced by Prucalopride was the same as that observed in wild-type mice. These data support 5-HT(4) receptors as a target for cognitive enhancement and suggest that a partial agonist would be sufficient to produce benefits, while reducing potential peripheral side effects. In addition, we show that 5-HT(4) receptors remain functional in the presence of excess Abeta peptide and may therefore be a useful target in AD.

A simple, high throughput method for the quantification of sodium alginates on oesophageal mucosa

Sodium alginate is a potential bioadhesive, but the lack of a convenient and suitable method for its quantification on the mucosal surface complicates the evaluation of its mucosal retentive properties. This paper develops and evaluates a spectrophotometric method for the rapid quantification of a range of sodium alginates differing in chemical composition, and investigates how quantification was influenced by the presence of oesophageal mucosa. The method, based on dye complexation with 1,9-dimethyl methylene blue (DMMB) was sensitive to alginate molecular weight and uronic acid composition, however, no significant correlations between assay performance and alginate molecular characteristics were demonstrated. The assay was also influenced by complexation time, calcium ions and mucin, but was unaffected by the presence of oesophageal tissue scrapings. The assay proved to be capable of quantifying sodium alginate with excellent linearity (r = 0.999), reproducibility (CV < 3%) and sensitivity (0.3 g l(-1)) and proved to be a precise, high-throughput method that may be used for quantifying the retention of sodium alginate on oesophageal mucosa.

Ultrastructural and behavioural changes precede amyloid deposition in a transgenic model of Alzheimer’s disease

We describe the thorough characterisation of a new transgenic mouse line overexpressing the 695-amino acid isoform of human amyloid precursor protein harbouring the Swedish double familial Alzheimer's disease mutation. This line, referred to as TAS10, exhibits neuropathological features and cognitive deficits that are closely correlated to the accumulation of Abeta in their brain and that are reminiscent of those observed in AD. Data on the TAS10 line are presented at five time points: 2, 6, 12, 18 and 24 months in a longitudinal study. The TAS10 line is characterised by the following changes: i) significant age-related increases in the levels of total and individual species (1-40, 1-42) of beta-amyloid in the brains of transgenics compared with non-transgenic littermates; ii) transgenic mice showed pronounced spatial learning deficits in the Morris water maze at 6 months and working memory deficits by 12 months; iii) amyloid plaque and associated pathologies were observed by the 12-month time point and the burden increased substantially, particularly in the cortex, by 18 months; iv) electron microscopy of the hippocampus of transgenic mice showed evidence of abnormal ultrastructural features such as dystrophic neurites and lipid deposits that developed from 6 months and increased in number and severity with age. Morphometric studies demonstrate that the synapse to neuron ratio is higher in transgenics than in control mice at 12 months, but this ratio decreases as they age and synapse size increases. Thus, this mouse model exhibits a close correlation of amyloid burden with behavioural deficits and ultrastructural abnormalities and so represents an ideal system to study the mechanisms underlying the impact of amyloid pathology on CNS function.

Presenilin 1 independently regulates beta-catenin stability and transcriptional activity

Presenilin 1 (PS1) regulates beta-catenin stability; however, published data regarding the direction of the effect are contradictory. We examined the effects of wild-type and mutant forms of PS1 on the membrane, cytoplasmic, nuclear, and signaling pools of endogenous and exogenous beta-catenin by immunofluorescence microscopy, subcellular fractionation, and in a transcription assay. We found that PS1 destabilizes the cytoplasmic and nuclear pools of beta-catenin when stabilized by Wnt or Dvl but not when stabilized at lower levels of the Wnt pathway. The PS1 mutants examined were less able to reduce the stability of beta-catenin. PS1 also inhibited the transcriptional activity of endogenous beta-catenin, and the PS1 mutants were again less inhibitory at the level of Dvl but showed a different pattern of inhibition toward transcription below Dvl. The transcriptional activity of exogenously expressed wild-type beta-catenin and two mutants, DeltaN89beta-catenin and DeltaSTbeta-catenin, were also inhibited by wild-type and mutant PS1. We conclude that PS1 negatively regulates the stability and transcriptional activity of beta-catenin at different levels in the Wnt pathway, that the effect on transcriptional activity appears to be independent of the GSK-3beta mediated degradation of beta-catenin, and that mutations in PS1 differentially affect the stability and transcriptional activity of beta-catenin.

Royal British Legion war grave pilgrimages: a medical escort's perspective

The Royal British Legion organizes pilgrimages to nearly all parts of the world where British servicemen and service-women and their allies fought and died. The Pilgrimage Department has taken thousands of widows, other relatives, veterans and friends to visit the grave of a loved one or comrade buried overseas. The parties of pilgrims are escorted by Service medical officers and nurses of the Regular and Reserve Armed Forces. The role of the medical escort is described.

The M31 gene has a complex developmentally regulated expression profile and may encode alternative protein products that possess diverse subcellular localisation patterns

HP1-like chromobox genes comprise an evolutionarily conserved family of genes that encode components of centromeric heterochromatin. In order to investigate the role of the murine HP1-like gene, M31, in heterochromatin formation we have isolated its gene and characterised its transcripts and protein products. PCR products that represent M31 transcripts were detected at the one-cell stage and were maternal in origin. Maternal provision of M31 transcripts may reflect a need for M31 in the formation of a functional centromere in order that there is proper segregation of chromosomes during the early cleavage divisions; studies in fission yeast and Drosophila have suggested a crucial role for HP1-like genes in centromere function. There are three protein products encoded by the M31 gene. Surprisingly, the two smaller products are found almost exclusively in the cytoplasm.

Identification of a set of proteins (C' and C) encoded by the bicistronic P gene of the Indiana serotype of vesicular stomatitis virus and analysis of their effect on transcription by the viral RNA polymerase

Previous work (C.F. Spiropoulou and S.T. Nichol, 1993, J. Virol. 67, 3103-3110) has demonstrated the existence in cells infected with the New Jersey serotype of vesicular stomatitis virus (VSV) of two small carboxy-coterminal proteins encoded by the P mRNA. These proteins have been named C' and C. We are interested in studying the function of these proteins in the virus life cycle. Toward this end, we have cloned the ORF encoding the potential C' protein of the Indiana serotype as a histidine-tagged fusion protein, purified the expressed protein from Escherichia coli, and used the fusion protein as an immunogen to raise antiserum in a rabbit. We have used this anti-C' protein serum to demonstrate that both of the predicted C' and C proteins are synthesized in cells infected with the Indiana serotype of VSV. In addition we have localized a portion of these proteins to nucleocapsids isolated from infected cells, suggesting that they may play a role in RNA synthesis. Reconstitution of the viral polymerase activity by expressing the L and P protein subunits with or without the C proteins failed to demonstrate any effect of the presence of these latter proteins on reconstituted transcription using purified nucleocapsids as templates. However, we have been able to show a dramatic stimulation of the polymerase activity in purified virions by the addition of purified C' protein to in vitro transcription reactions. Both the level and the fidelity of mRNA synthesis are stimulated by this protein. Evidence for the specificity of this effect comes from the fact that stimulation appears to be serotype specific; C' protein of the Indiana serotype stimulates transcription by purified Indiana serotype virions but has a minimal effect on transcription by purified virions of the New Jersey serotype. We are continuing our studies to determine the mechanism of this stimulation.

Evaluation of media and techniques to enumerate heterotrophic microbes from karst and sand aquifer springs

Several media and techniques were compared for their efficiency to enumerate viable heterotrophs from both a karst and sand aquifer spring. A medium designed to enumerate bacteria from nutrient-poor waters (HCFU) as well as R2A medium proved superior to tryptic soy agar; however, the difference was always less than one order of magnitude. Membrane filtration resulted in lower counts of microbes than the spread plate, multitube turbidity, or drop plate methods from samples of both sand and karst springs. The drop plate technique yielded higher viable counts from the sand spring and basin of the karst spring, with a precision of 21% (coefficient of variation) and a maximum plating efficiency of 3.4% (viable count/direct count × 100). Subsequently, 63% of isolates from drop plates were recovered on HCFU. Microcolonies were visible by epifluorescence microscopy, acridine orange staining, and subsequent examination of excised agar sections containing drops.

Inhibition of VSV genome RNA replication but not transcription by monoclonal antibodies specific for the viral P protein

The growth of vesicular stomatitis virus requires two distinct RNA synthetic events: transcription of messenger RNA molecules and replication of the viral genome RNA. We report the use of a panel of monoclonal antibodies directed against the viral phosphoprotein P in an attempt to assess the role of this protein in RNA synthesis. Using extracts derived from virus-infected cells, we show that several anti-P monoclonal antibodies can have an inhibitory effect on genome RNA replication by binding to a soluble form of the P protein. We also show that the P protein to which one of these antibodies (6D11) is directed is not complexed with the N protein and that the amount of soluble P protein that binds to the 6D11 antibody in immunoprecipitation reactions can be increased by treating extracts with alkaline phosphatase. In addition, phosphatase treatment of infected cell extracts results in an increased level of genome RNA replication. These results suggest that a soluble subspecies of the P protein that functions in genome RNA replication exists in infected cells and that this species of the P protein is not required for transcription.

Developmental effects of over-expression of normal and mutated forms of a Xenopus NF-kappa B homologue

High level over-expression of XrelA1, a homologue of the p65 sub-unit of NF-kappa B and of Drosophila dorsal, arrests Xenopus development at the gastrula stage, producing a reduction in the levels of expression of various genes of developmental interest without general reduction in transcription or cessation of cell division. There is little Goosecoid expression, even though a dorsal lip forms. At lower levels XrelA1 mRNA primarily produces disruption of the mid-dorsal axis. A dominant interference gene product, delta 222, produces mainly posterior, but also anterior abnormalities. On the basis of these results we postulate that the role of XrelA1 in the vertebrate embryo is unlikely to be in dorsoventral development, but more likely in the formation of the termini.

XrelA, a Xenopus maternal and zygotic homologue of the p65 subunit of NF-kappa B. Characterisation of transcriptional properties in the developing embryo and identification of a negative interference mutant

We have isolated two clones (XrelA.1 and XrelA.2) from Xenopus ovary representing differentially processed mRNAs homologous throughout their translated regions to the mammalian p65 subunit of NF-kappa B. The transcripts are ubiquitously present throughout development, but are most abundant in late blastulae and gastrulae. Overproduced protein shows nuclear localisation in both oocytes and early embryos. The XrelA.2 product bound to DNA as an oligomer which was not detected in the normal embryo. Two endogenous kappa B-binding complexes were present, showing no stage-specific variation, although one was relatively deficient in posterior regions of the early neurula. They were not disrupted by dimerization with over-expressed XrelA, suggesting that they were not produced by NF-kappa B/Rel/dorsal family members. The transcriptional properties of the cloned XrelA were assayed in intact embryos by co-injecting XrelA mRNA and a linear HIV LTR-driven CAT reporter gene. CAT levels were stimulated 20-30-fold by XrelA mRNA levels in the 100 pg range, and this was wholly dependent on NF-kappa B binding sites, and largely dependent on those for SP-1. These results were remarkably reproducible and show that quantitative analysis of transcription factor function is possible in intact developing Xenopus embryos A mutant lacking the transcriptional activation domain antagonised co-injected wild-type XrelA, providing a potential dominant negative p65 mutant for interfering with NF-kappa B function in analysing NF-kappa B function in normal development.

MHC class I gene expression is negatively regulated by the proto-oncogene, c-jun

The trans-acting factor AP-1 is a heterodimeric complex composed of c-Jun and c-Fos family proteins which bind and regulate genes containing a TPA responsive enhancer element. Although AP-1 binding sites have been identified within the regulatory region of major histocompatibility complex (MHC) class I genes in vitro, the role of AP-1 in regulating MHC class I transcription in vivo has not been investigated previously. The present study demonstrates that expression of c-Jun results in decreased MHC class I promoter activity as determined in cotransfection assays of an MHC class I reporter construct with a c-Jun expression construct. The c-Jun responsive element is located between bp -440 and -431 upstream of initiation of transcription as determined both functionally and by direct binding of purified c-Jun. Furthermore, over-expression of c-Jun reduced the steady state levels of endogenous MHC class I RNA in murine L cells by approximately 10-fold. These data indicate that c-Jun/AP-1 acts as a negative trans-acting factor that down-regulates MHC class I gene expression.

Creation of mice expressing human antibody light chains by introduction of a yeast artificial chromosome containing the core region of the human immunoglobulin kappa locus

We have previously described a strategy for integrating selectable marker genes into yeast artificial chromosomes (YACs) to facilitate their transfer into embryonic stem (ES) cells. Here we apply this technology to create mice carrying the core region of the human immunoglobulin (Ig) kappa light chain locus. A YAC was isolated which contains a 300 kb insert spanning three V kappa segments, the J kappa cluster, the C kappa region and extending downstream of the Kde element. After modification of this YAC to integrate the selectable neo marker gene, the YAC was introduced into ES cells by protoplast fusion. Several ES cell clones were obtained which appeared to harbor one complete copy of the YAC while retaining little or no other yeast DNA. The ES cells were injected into blastocysts and the chimaeric mice were shown to rearrange the introduced human light chain genes with the resultant production of antibodies containing human kappa light chains in the serum.

In vivo function of regulatory DNA sequence elements of a major histocompatibility complex class I gene

Major histocompatibility complex class I genes are expressed in nearly all somatic tissues, although their level of expression varies. By analysis of a set of promoter deletion mutants introduced into transgenic mice, a complex regulatory element, consisting of overlapping enhancer and silencer activities, is demonstrated to function as a tissue-specific regulator of class I expression. The enhancer activity predominates in lymphoid tissues but not in nonlymphoid tissues. In contrast to the tissue-specific functions of the complex regulatory element, a second novel silencer element is shown to function in both lymphoid and nonlymphoid tissues. The complement of DNA-binding factors in different cell lines is shown to correlate with the levels of class I expression.

NS2 protein of influenza virus is found in purified virus and phosphorylated in infected cells

Purified viral preparations of influenza A virus were examined for the presence of NS2 protein hitherto considered as a viral nonstructural protein that is present only in infected cells. Analysis of purified virus by radioimmunoprecipitation with monospecific antisera to NS2 revealed its presence in the virus particle suggesting that it is a viral structural protein. NS2 protein was also shown to be phosphorylated in infected cells in this study. This brings the number of influenza virus phosphoproteins to three which include NP, NS1, and NS2. These observations raise important questions about the role of NS2 in the replication of influenza virus.

Heterogeneous forms of polymerase proteins exist in influenza A virus-infected cells

In influenza virus-infected cells a virus coded polymerase that consists of three polypeptide subunits, namely PB1, PB2 and PA, mediates both transcription and replication. Radioimmunoprecipitation with monospecific antisera to each of the polymerase proteins revealed additional forms of PB1 and PA proteins in infected cells. PA antiserum detected two additional proteins of 62k and 60k and PB1 antiserum recognized two additional proteins of 85k and 70k. Further investigation was carried out on the 62k PA and 85k PB1 related proteins. Limited proteolysis peptide mapping showed that these proteins are subsets of their normal counter-parts. These new forms of polymerase proteins are designated as "b" forms (PAb and PB1b) to distinguish them from the previously recognized forms designated as "a" forms (PAa and PB1a). Both PAb and PB1b proteins were found in cells infected with all the influenza type A viruses tested indicating that they are evolutionarily conserved. Pulse chase experiments showed that the "b" forms are not derived from "a" forms. This suggested that "b" forms are translated independently. The "b" forms were not detected in purified virus but were found to be associated with intracellular RNP templates, suggesting a role for these proteins in intracellular virus replication events.

The use of primed cytotoxic T lymphocytes as a highly sensitive and accurate method for the detection of MHC disparate allogeneic cells

The present studies have investigated the use of primed cytotoxic T cells (CTL) for the purpose of detecting the presence of an MHC disparate allogeneic cell population. The findings indicate that restimulation of primed CTL in the presence of activated T cell supernatants is an extremely sensitive method capable of detecting one allogeneic cell within a population containing 10,000 total cells (0.01%). In addition, this primed lymphocyte cytotoxicity assay (PLCA) was shown to be at least as accurate as flow cytometric analysis in determination of low numbers and percentages of allogeneic cells within the cell population being examined. Furthermore, the nature of the allogeneic mononuclear population did not influence the sensitivity or accuracy of this method. To examine this method's applicability for the detection of chimeric populations in vivo, spleen and thymic tissue from neonatally tolerized animals were examined by PLCA analysis. Allogeneic cells were readily detected in 100% of individual host spleen and thymuses tested. In total, the results showed that the PLCA is a highly reproducible and accurate method for the detection of extremely low numbers of allogeneic cells. This approach should be useful to monitor the presence of foreign cells in experimental and clinical situations in which individuals are exposed to allogeneic cell populations.

Exploring the persistent black risk of low birthweight: findings from the GLOWBS Study

Results are presented from the Galveston Low Birthweight Survey (GLOWBS) Study, a tri-ethnic survey (N = 1,179) of live, single births, conducted in Galveston, Texas, from 1986 to 1987. Four principal findings emerged pointing to a persistent black risk for low birthweight (less than 2,500g). First, black infants (2,997g) have significantly lower mean birthweight than either Anglos (3,281g) or Hispanics (3,270g). Second, blacks are at significantly higher risk of low birthweight than nonblacks (risk ratio = 1.71). Third, despite controlling for a variety of pregnancy- and health-related, psychosocial, socioeconomic, and health services factors (including even gestational length), being black still exerts a significant, inverse effect on birthweight (beta = -0.137). Fourth, of the above factors only gestational length (R2 = 0.39) accounts for more than a negligible amount of the total variance in birthweight among blacks. These findings are discussed, and several lines of follow-up research are proposed.

Kinesigenic choreoathetosis due to brain injury

This uncommon paroxysmal movement disorder featuring attacks of dystonic spasm with athetoid posturing is usually of idiopathic nature, often familial and starting in childhood. There are a few reported examples due to cerebral pathology, and only four previous cases due to brain trauma. We report here a 21 year old man with left-sided motor spasms, choreoathetoid in type, which were clearly caused by a right frontal penetrating injury with contusion and haemorrhage. The attacks were relieved by phenytoin therapy. In this case, it seems that the post-traumatic paroxysmal kinesigenic choreoathetosis may be a form of reflex epilepsy.

Utilization of antigen specific cytotoxic T-cells as a sensitive approach to investigate the fate of placentally injected allogeneic lymphocytes

In this report we present a model for the introduction of immunocompetent populations during murine gestation and the subsequent detection of allogeneic cells in the offspring. A highly sensitive in vitro assay, the primed lymphocyte cytotoxicity assay, which can detect extremely low numbers of allogeneic cells residing within host tissue is described. Primed cytotoxic T cells specific for class I antigens were found to be restimulated by as few as 10-50 allogeneic spleen cells from within 10,000 syngeneic neonatal spleen or liver cells. Various tissues derived from neonatal mice which had been placentally injected 1 or 10 days previously were found to contain markedly different percentages of "chimeric" cells in the neonatal organs examined. Notably, while spleen and lung contained more allogeneic cells early following injection, 10 days later the liver contained the highest percentage and the thymus and spleen a significantly lower percentage of allogeneic cells. These findings are discussed with respect to the possible enhancement or depression of the offspring's immune responsiveness following interaction with alloantigen bearing lymphoid cells.

Absence of mutagenic activity of benorylate, paracetamol and aspirin in the Salmonella/mammalian microsome test

Benorylate and its two major hydrolysis products, paracetamol and aspirin were examined for mutagenicity in the Salmonella/mammalian microsome screening test. The compounds were tested in 6 strains of Salmonella typhimurium (TA1535, TA1537, TA1538, TA100, TA97 and TA98) in the presence and absence of a rat-liver microsome activation system. Benorylate did not show evidence of mutagenic activity in the 6 strains tested with or without metabolic activation at concentrations ranging from 0.006 to 3 mg per plate. Paracetamol and aspirin likewise did not show any evidence of mutagenic activity at concentrations ranging from 0.1 to 50 mg per plate for the former and 0.01 to 50 mg per plate for the latter.

Molecular localization of allogeneic and self determinants recognized by bulk and clonal populations of cytotoxic T cells

The localization of MHC-encoded determinants recognized by hapten- and allo-specific cytotoxic T cells was analyzed with the use of cell lines expressing recombinant H-2Dd and H-2Ld MHC products. Bulk cultures of CTL against TNP-self, FITC-self, and AED-self recognized self determinants associated with the N/C1 domains of both Dd and Ld products. A number of allo- and hapten-specific CTL clones were also tested for recognition of the recombinant MHC products. The allo clones specific for Ld or Dd antigens recognized the respective N/C1-associated determinants. In addition, all clones generated against H-2q and known to cross-react with H-2Dd antigens recognized determinants associated with the N/C1-associated Dd determinants. Thus, some of the results obtained with CTL parallel, whereas others contrast with, those findings obtained with monoclonal anti-H-2 antibodies. Similar to the observations made with the monoclonal antibodies, no determinant as defined by T cells has been found to be lost as a result of the interaction between the N/C1 and C2/M domains of the Ld and Dd proteins. Nor did our studies detect the presence of new antigens resulting from the interaction of these gene products. However, the present T cell findings continue to contrast previous results demonstrating that antibody interaction with class I products includes recognition of C2/M-associated epitopes.

Comparison between glycopyrrolate and atropine in a mixture with neostigmine for reversal of neuromuscular blockade. Studies in patients following open heart surgery

Atropine and glycopyrrolate were compared in a mixture with neostigmine for reversal of neuromuscular blockade in patients undergoing open heart surgery. In patients not receiving beta-blocking drugs, glycopyrrolate was shown to possess advantages over atropine in terms of a lower initial increase in heart rate, better protection against the muscarinic effects of neostigmine, and smaller increases in rate-pressure product. The concomitant administration of beta-adrenergic blocking therapy significantly attenuated the effect of reversal on heart rate and the differences between atropine and glycopyrrolate were not significant. There was no difference in the incidence of arrhythmias between patients who received beta-blocking drugs and those who did not.

Molecular localization of allogeneic and self determinants recognized by bulk and clonal populations of cytotoxic T cells

The localization of MHC-encoded determinants recognized by hapten- and allo-specific cytotoxic T cells was analyzed with the use of cell lines expressing recombinant H-2Dd and H-2Ld MHC products. Bulk cultures of CTL against TNP-self, FITC-self, and AED-self recognized self determinants associated with the N/C1 domains of both Dd and Ld products. A number of allo- and hapten-specific CTL clones were also tested for recognition of the recombinant MHC products. The allo clones specific for Ld or Dd antigens recognized the respective N/C1-associated determinants. In addition, all clones generated against H-2q and known to cross-react with H-2Dd antigens recognized determinants associated with the N/C1-associated Dd determinants. Thus, some of the results obtained with CTL parallel, whereas others contrast with, those findings obtained with monoclonal anti-H-2 antibodies. Similar to the observations made with the monoclonal antibodies, no determinant as defined by T cells has been found to be lost as a result of the interaction between the N/C1 and C2/M domains of the Ld and Dd proteins. Nor did our studies detect the presence of new antigens resulting from the interaction of these gene products. However, the present T cell findings continue to contrast previous results demonstrating that antibody interaction with class I products includes recognition of C2/M-associated epitopes.

The products of transferred H-2 genes express determinants that restrict hapten-specific cytotoxic T cells

Cell lines into which cloned H-2 genes had been introduced (i.e., transformants) were used to correlate the genes and their products that are capable of functioning as H-2 restriction elements for hapten-self-(AED and TNP) specific cytotoxic T cells (CTL). These transformants provided a unique system in which major histocompatibility restricted (MHC) T cell recognition could be examined by using cells that express only H-2Ld or only H-2Dd gene products. BALB/c (H-2d) anti AED-self CTL lysed both the H-2Ld and Dd transformants, but not parental, i.e., untransformed, cells. The AED-self lysis of the Ld and Dd transformants was shown to be specifically inhibited by anti-H-2Ld and anti H-2Dd monoclonal antibody, respectively. In contrast to these results, BALB/c anti TNP-self CTL were found to lyse readily the Dd but not Ld transformed lines, supporting reports indicating that H-2Ld-restricted TNP-self CTL could not be detected. The results of this study thus demonstrate that the cell surface products encoded by these transferred MHC class I genes contain self determinants recognized by CTL.