Chandra X-Ray Observations of the Hydra A Cluster: An Interaction between the Radio Source and the X-Ray-emitting Gas

We present Chandra X-ray observations of the Hydra A cluster of galaxies, and we report the discovery of structure in the central 80 kpc of the cluster's X-ray-emitting gas. The most remarkable structures are depressions in the X-ray surface brightness, approximately 25-35 kpc in diameter, that are coincident with Hydra A's radio lobes. The depressions are nearly devoid of X-ray-emitting gas, and there is no evidence for shock-heated gas surrounding the radio lobes. We suggest that the gas within the surface brightness depressions was displaced as the radio lobes expanded subsonically, leaving cavities in the hot atmosphere. The gas temperature declines from 4 keV at 70 kpc to 3 keV in the inner 20 kpc of the brightest cluster galaxy (BCG), and the cooling time of the gas is approximately 600 Myr in the inner 10 kpc. These properties are consistent with the presence of an approximately 34 M middle dot in circle yr-1 cooling flow within a 70 kpc radius. Bright X-ray emission is present in the BCG surrounding a recently accreted disk of nebular emission and young stars. The star formation rate is commensurate with the cooling rate of the hot gas within the volume of the disk, although the sink for the material that may be cooling at larger radii remains elusive. A bright, unresolved X-ray source is present in the BCG's nucleus, coincident with the radio core. Its X-ray spectrum is consistent with a power law absorbed by a foreground NH approximately 4x1022 cm-2 column of hydrogen. This column is roughly consistent with the hydrogen column seen in absorption toward the less, similar24 pc diameter VLBA radio source. Apart from the point source, no evidence for excess X-ray absorption above the Galactic column is found.

Co-localisation of CCG repeats and chromosome deletion breakpoints in Jacobsen syndrome: evidence for a common mechanism of chromosome breakage

Folate-sensitive fragile sites are associated with the expansion and hypermethylation of CCG-repeats. The fragile site in 11q23.3, FRA11B, has been shown to cause chromosome deletions in vivo, its expression being associated with Jacobsen (11q-) syndrome. However, the majority of Jacobsen deletions are distal to FRA11B and are not related to its expression. To test the hypothesis that other unidentified fragile sites might be located in 11q23.3-24 and may cause these deletions, we have identified and characterised CCG-trinucleotide repeats within a 40 Mb YAC contig spanning distal chromosome 11q. Only eight CCG-repeats were identified within the entire YAC contig (not including FRA11B ), six of which map to the region of 11q23.3-24 that includes Jacobsen deletions. We have previously collated the deletion mapping data of 24 Jacobsen patients with the physical map of chromosome 11q, and accurately localised six breakpoints to short intervals corresponding to individual YAC clones. We now show that in each of these cases, YAC clones found to contain a deletion breakpoint also contain a CCG-repeat. The improved analysis of one of these deletions, together with those of several new Jacobsen cases, further strengthens this association by localising five breakpoints to individual PAC clones containing CCG-repeats. These data provide strong evidence for the non-random clustering of chromosome deletion breakpoints with CCG-repeats, and suggests that they may play an important role in a common mechanism of chromosome breakage.

Full assignment of the proton and carbon NMR spectra and revised structure for the capsular polysaccharide from Streptococcus pneumoniae type 17F

Full proton, 13C and 31P NMR assignments for the capsular polysaccharide from Streptococcus pneumoniae Type 17F are reported, and a revised structure differing in the anomeric configuration of the sidechain beta-Galp residue proposed. This polysaccharide is a component of the current 23-valent polysaccharide vaccine. The implications of this revised structure for published work are discussed.

A systems approach to medication error reduction

An interdisciplinary process for the reduction of medication errors was implemented at East Jefferson General Hospital in Metairie, Louisiana, a suburb of New Orleans. The Medication Administration Review and Safety Committee expanded the error reporting system with a comprehensive concurrent chart review process. Safe administration of medications through a systems approach has led to a reduction of documentation deficiencies, a new follow-up process, and an increase in reported errors.

Relationship between dopamine D(2) occupancy, clinical response, and side effects: a double-blind PET study of first-episode schizophrenia

OBJECTIVE

Since all antipsychotics block dopamine D(2) receptors, the authors investigated how well D(2) receptor occupancy in vivo predicts clinical response, extrapyramidal side effects, and hyperprolactinemia.

METHOD

In a double-blind study, 22 patients with first-episode schizophrenia were randomly assigned to 1.0 or 2. 5 mg/day of haloperidol. After 2 weeks of treatment, D(2) receptor occupancy was determined with [(11)C]raclopride and positron emission tomography, and clinical response, extrapyramidal side effects, and prolactin levels were measured. Patients who showed adequate responses continued taking their initial doses, those who did not respond had their doses increased to 5.0 mg/day, and evaluations were repeated at 4 weeks for all patients.

RESULTS

The patients showed a wide range of D(2) occupancy (38%-87%). The degree of receptor occupancy predicted clinical improvement, hyperprolactinemia, and extrapyramidal side effects. The likelihood of clinical response, hyperprolactinemia, and extrapyramidal side effects increased significantly as D(2) occupancy exceeded 65%, 72%, and 78%, respectively.

CONCLUSIONS

The study confirms that D(2) occupancy is an important mediator of response and side effects in antipsychotic treatment. The data are consistent with a "target and trigger" hypothesis of antipsychotic action, i.e., that the D(2) receptor specificity of antipsychotics permits them to target discrete neurons and that their antagonist properties trigger within those neurons intracellular changes that ultimately beget antipsychotic response. While limited to haloperidol, the relationship between D(2) occupancy and side effects in this study helps explain many of the observed clinical differences between typical and atypical antipsychotics.

Blastic/blastoid transformation of follicular lymphoma: immunohistologic and molecular analyses of five cases

Progression of follicular lymphoma to a higher-grade malignancy frequently heralds a poor prognosis. Clinical transformation is variably accompanied by a spectrum of histologic changes characterized by alteration in growth and cytology. Although several cytogenetic events and potential oncogenes have been documented in this progression, the underlying molecular mechanisms are largely unknown. We present five patients with an unusual histologic transformation of follicular lymphoma manifested by blastic/blastoid morphology. This transformation is histologically distinct from other types of transformation of follicular lymphoma. All five cases exhibited the t(14;18) translocation and expressed the BCL-2 protein. In addition, two of the five patients showed increased levels of the p53 protein within neoplastic cells implicating a possible role for this oncogene in blastic/blastoid transformation. The lack of BCL-1 and myeloid antigens by immunohistochemistry and flow cytometry studies served to distinguish blastic/blastoid transformation of follicular lymphoma from its morphologic mimics. This distinction is clinically important because lymphoblastic and myeloid leukemias require significantly different therapeutic modalities and show better prognosis. Moreover, the lack of Epstein-Barr virus-specific mRNA suggests that this virus is unlikely to participate in blastic/blastoid transformation of follicular lymphoma.

Improving the reproducibility of the MCF-7 cell proliferation assay for the detection of xenoestrogens

The MCF-7 cell proliferation assay is potentially a simple and highly reproducible tool for the identification of estrogenic compounds. However, its widespread use has been complicated by the lack of a standardised protocol, resulting in considerable inter-laboratory variability. We have explored the sources of variability both in relation to cell lines and test regimens and report on optimised procedures for the identification of estrogenic agents. Two supposedly identical MCF-7 parent cell lines (designated UCL and SOP), and the BUS subline were cultured according to an existing protocol, and responses to 17-estradiol (E2) assessed. Despite yielding almost identical EC50 values, the proliferative response varied widely between cell lines from 0.98-fold over controls (UCL) to 8.9-fold (BUS) indicating major differences between them. The underlying causes may be genetic, and to assess this we used comparative genomic hybridisation (CGH), a technique which allows the detection of DNA sequence copy number changes on a genome-wide scale. Although numerous similarities existed between the different cell lines, the least oestrogen-responsive line (MCF-7/UCL) exhibited the greatest number of cytogenetic changes, many of which were not seen in MCF-7/SOP cells. We suggest that care must be taken, therefore, when choosing a cell line for MCF-7 cell-based experiments. Selecting the MCF-7/SOP line for further work, we carried out a thorough and systematic optimisation of the MCF-7 cell proliferation assay, finding that a 72-h period in oestrogen-free medium before treatment strongly influenced the cells response to E2. With 1 nM E2, proliferation increased from 1.5-fold to 6.5-fold relative to vehicle-treated controls, a response similar to that seen with MCF-7/BUS cells in the E-SCREEN protocol devised by Soto et al. With parent MCF-7 cells, other laboratories have reported only 4.5-fold increases as maximal. Here we present evidence that the choice of cell line and culture conditions are crucial in determining test outcomes, and once chosen and adhered to the assay yields reproducible results.

RAPD library fingerprinting of bacterial and human DNA: applications in mutation detection

Random amplified polymorphic DNA (RAPD) fingerprinting is a modification of the polymerase chain reaction (PCR), which utilises a single, arbitrarily-chosen primer to amplify a number of fragments from a given template DNA to generate a discrete "fingerprint" when resolved by gel electrophoresis. Alterations by as little as a single base in the primer sequence lead to marked alterations in the fingerprints generated with a given template under optimised conditions. By inference, single base alterations in the genomic template DNA may also lead to changes in the RAPD fingerprints. We have examined this potential application to detect mutations in bacteria and cultured human cells. We have utilised Escherichia coli and human lymphoblastoid cell lines exposed to UV radiation, selected for by cellular mutation assays, and compared RAPD fingerprints of mutant and non-mutant samples. Polymorphisms became evident as the presence and/or absence of DNA fragments between the two samples. A dose-dependent increase in the number of polymorphic bands was seen with UV irradiation of E. coli. To a lesser degree, polymorphisms were also evident for human lymphoblastoid DNA. The possible underlying mechanisms for these alterations in fingerprints as a result of mutation(s) in the primer binding site(s) are discussed. The ability of RAPD fingerprinting to detect a mutant in a population of non-mutants is evaluated, and whilst the lack of sensitivity inherent in the technique precludes its use as a mutation screening assay, its potential for generation of mutant and non-mutant DNA probes for other mutation detection techniques may prove to be of great merit. Teratogenesis Carcinog. Mutagen. 20:49-63, 2000.

Comparison of PCR detection methods for B1, P30, and 18S rDNA genes of T. gondii in aqueous humor

PURPOSE

Comparison of polymerase chain reaction (PCR) amplification of three Toxoplasma gondii genes in aqueous humor.

METHODS

Nested PCRs carried out using published methods were optimized for maximum sensitivity and specificity. Five pairs of oligonucleotide primers, directed against the B1, P30, and ribosomal genes, were used and compared to determine which sequences were most effective in detecting T. gondii DNA. Methods were developed with DNA templates in water and were subsequently applied to both normal and inflamed aqueous.

RESULTS

After one round of PCR amplification, P30 and ribosomal primers were able to detect 1 pg genomic T. gondii DNA. However, those directed against the B1 gene were able to detect 50 fg (approximately single tachyzoite). This level of sensitivity was also achieved using the P30 primers after a second round of PCR; however, only primers based on the B1 gene maintained this level of sensitivity in both normal and inflamed aqueous. B1-specific primers did not amplify sequences from fungal, bacterial, or human lymphocyte DNA. The sensitivity of T. gondii detection using B1 gene-specific primers was not compromised when large amounts of human lymphocyte DNA were present, and application to an ocular sample or retinal section from patients with toxoplasma chorioretinitis was successful in confirming the presence of T. gondii DNA.

CONCLUSIONS

The B1 PCR protocol appears to be the most sensitive protocol in the detection of T. gondii DNA and has been successful in identification of T. gondii DNA in ocular fluids and retinal sections. This provides direct evidence of the presence of T. gondii within the eye and may therefore help in the management of toxoplasma retinochoroiditis.

A Chandra High-Resolution X-ray Image of Centaurus A

We present first results from a Chandra X-Ray Observatory observation of the radio galaxy Centaurus A with the High-Resolution Camera. All previously reported major sources of X-ray emission including the bright nucleus, the jet, individual point sources, and diffuse emission are resolved or detected. The spatial resolution of this observation is better than 1&arcsec; in the center of the field of view and allows us to resolve X-ray features of this galaxy not previously seen. In particular, we resolve individual knots of emission in the inner jet and diffuse emission between the knots. All of the knots are diffuse at the 1&arcsec; level, and several exhibit complex spatial structure. We find the nucleus to be extended by a few tenths of an arcsecond. Our image also suggests the presence of an X-ray counterjet. Weak X-ray emission from the southwest radio lobe is also seen, and we detect 63 pointlike galactic sources (probably X-ray binaries and supernova remnants) above a luminosity limit of approximately 1.7x1037 ergs s-1.

Glycoconjugate vaccines

Licensed glycoconjugate vaccines provide protective immunity against bacterial pathogens by eliciting a T-cell-dependent immune response to the corresponding bacterial saccharide covalently linked to a protein carrier. The field is rapidly expanding to include the introduction of novel carrier proteins and conjugation chemistries, the development of novel antimicrobial vaccines and an improved understanding of the mechanisms by which these vaccines induce protective responses. An exciting application is to the area of antitumor immunotherapeutics.

Comparative genomic hybridization reveals extensive variation among different MCF-7 cell stocks

Comparative genomic hybridization (CGH) allows the detection of DNA sequence copy number changes on a genome-wide scale in a single hybridization reaction. The ability of CGH to be applied to formalin-fixed, paraffin-embedded tumor samples has lead to its widespread application in the cytogenetic analysis of archival material. When setting up CGH in the laboratory, rigorous control experiments must be carried out to ensure that the losses and gains are scored correctly. Groups interested in breast cancer frequently use the MCF-7 cell line as a positive control in these experiments, comparing the results to previously described genetic alterations. Here we present the results of CGH carried out with three stocks of MCF-7 cells. The cells differ widely in their proliferative response to 17-beta estradiol and show extensive variation in copy number changes affecting specific chromosomal regions. We suggest that care must be taken, therefore, when choosing a cell line as a positive control for CGH experiments.

Disturbed memory and amnesia related to intensive care

Patients, when admitted to an intensive care unit (ICU), have one thing in common: their illness is life-threatening. Patients may remain on ICU in a critical condition, needing support with their breathing, circulation, and/or kidneys for varying lengths of time, from days to weeks. During that time the patients will receive sedative and analgesic drugs to ensure compliance with artificial ventilation. Patients recovering from critical illness frequently have little or no recall of their period in ICU, or remember nightmare, hallucinations, or paranoid delusions. The nature, extent and reason for these difficulties, have been under-reported and consequently our purpose was to conduct a review of memory problems experienced by ICU patients. A systematic literature review of computer databases (Medline, PsycLit, and CINAHL) identified 25 relevant papers. In addition, other relevant articles were obtained, citation lists and associated articles retrieved. Due to lack of research on processes underlying memory problems in ICU patients all articles that introduced an insight into possible mechanisms were included in the review. There seem to be two possible processes contributing to memory problems in ICU patients. First the illness and treatment may have a general dampening effect on memory. Delirium and sleep disturbance are both common in ICU patients. Delirium can result in a profound amnesia for the period of confusion. Sleep deprivation exacerbates the confusional state. Slow wave sleep is important for the consolidation of episodic memories. Treatment administered to patients in ICU can have effects on memory. Opiates, benzodiazepines, sedative drugs such as propofol, adrenaline, and corticosteroids can all influence memory. In addition, the withdrawal of drugs, such as benzodiazepines, can cause profound withdrawal reactions, which may contribute to delirium. Second, we hypothesise that there is a process that affects memory negatively for external events but enhances memory for internal events. The physical constraints and social isolation experienced by ICU patients and the life-threatening nature of the illness may increase the experience of hypnagogic hallucinations. Attentional shift during hypnagogic images from external stimuli to internally generated images would explain why ICU patients have such poor recall of external ICU events, but can clearly remember hallucinations and nightmares. Patients describe these memories as being very vivid and this is explored in terms of flashbulb memory formation. The absence of memories for real events on ICU can result in ICU patients remembering paranoid delusions of staff trying to kill them, with little information to reject these vivid memories as unreal. This has implications for patients' future psychological health.

Virus-induced neuronal apoptosis blocked by the herpes simplex virus latency-associated transcript

Latent infections with periodic reactivation are a common outcome after acute infection with many viruses. The latency-associated transcript (LAT) gene is required for wild-type reactivation of herpes simplex virus (HSV). However, the underlying mechanisms remain unclear. In rabbit trigeminal ganglia, extensive apoptosis occurred with LAT(-) virus but not with LAT(+) viruses. In addition, a plasmid expressing LAT blocked apoptosis in cultured cells. Thus, LAT promotes neuronal survival after HSV-1 infection by reducing apoptosis.

Chandra X-Ray Detection of the Radio Hot Spots of 3C 295

An observation of the radio galaxy 3C 295 during the calibration phase of the Chandra X-Ray Observatory reveals X-ray emission from the core of the galaxy, from each of the two prominent radio hot spots, and from the previously known cluster gas. We discuss the possible emission processes for the hot spots and argue that a synchrotron self-Compton (SSC) model is preferred for most or all of the observed X-ray emission. SSC models with near-equipartition fields thus explain the X-ray emission from the hot spots in the two highest surface brightness FR II radio galaxies, Cygnus A and 3C 295. This lends weight to the assumption of equipartition and suggests that relativistic protons do not dominate the particle energy density.

Inhibition of L-homocysteic acid and buthionine sulphoximine-mediated neurotoxicity in rat embryonic neuronal cultures with alpha-lipoic acid enantiomers

In the present report, we have set out to investigate the potential capacity of both the oxidised and reduced forms of RS-alpha-lipoic acid, and its separate R-(+) and S-(-)enantiomers, to prevent cell death induced with L-homocysteic acid (L-HCA) and buthionine sulphoximine (BSO) in rat primary cortical and hippocampal neurons. L-HCA induced a concentration-dependent neurotoxic effect, estimated by cellular 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) reduction, in primary neurons, but was significantly more toxic for hippocampal (EC(50)=197 microM) compared with cortical neurons (EC(50)=1016 microM) whereas D-HCA demonstrated only moderate (<20%) toxicity. On the other hand, cortical and hippocampal cultures were equally susceptible (341 and 326 microM, respectively) to the neurotoxic action of BSO. Antioxidants including butylated hydroxyanisole, propyl gallate and vitamin E protected cells against the neurotoxic effect of L-HCA and BSO. However, N-acetyl-cysteine and tert-butylphenyl nitrone, although capable of abrogating L-HCA-mediated cell death showed no protective effect against BSO-mediated toxicity. RS-alpha-lipoic acid, RS-alpha-dihydrolipoic acid and the enantiomers R-alpha-lipoic acid and S-alpha-lipoic acid protected cells against L-HCA-mediated toxicity with EC(50) values between 3.1-8.3 microM in primary hippocampal neurons and 2.6-16.8 microM for cortical neurons. However, RS-alpha-lipoic acid, RS-alpha-dihydrolipoic acid, and S-alpha-lipoic acid failed to protect cells against the degeneration induced by prolonged exposure to BSO, whereas the natural form, R-alpha-lipoic, was partially active under the same conditions. The present results indicate a unique sensitivity of hippocampal neurons to the effect of L-HCA-mediated toxicity, and suggest that RS-alpha-lipoic acid, and in particular the R-alpha-enantiomeric form is capable of preventing oxidative stress-mediated neuronal cell death in primary cell culture.

First observation of the decay B --> J/psistraight phiK

We present the first observation of the decay B-->J/psistraight phiK. Using 9.6x10(6) B&Bmacr; meson pairs collected with the CLEO detector, we have observed ten fully reconstructed B-->J/psistraight phiK candidates, whereas the estimated background is 0.5+/-0.2 event. We obtain a branching fraction of B(B-->J/psistraight phiK) = (8. 8(+3.5)(-3.0)[stat]+/-1.3[syst])x10(-5). This is the first observed B meson decay requiring the creation of an additional s&smacr; quark pair.

SH2-Containing protein tyrosine phosphatase-1 (SHP-1) association with Jak2 in UT-7/Epo cells

We have investigated the interaction of the SH2-containing protein tyrosine phosphatase-1 (SHP-1) and Jak2 in an erythropoietin (Epo)-dependent human leukemia cell line, UT-7/Epo, using reciprocal immunoprecipitation and immunoblotting. The Epo-induced kinetics and dose response on phosphorylated Jak2 in anti-SHP-1 precipitates of UT-7/Epo cell lysates were similar to those in direct anti-Jak2 precipitates, suggesting that Jak2 coprecipitated with SHP-1. Furthermore, immunoblotting with anti-Jak2 and anti-SHP-1 antibodies indicated that SHP-1 appeared to be constitutively associated with non-tyrosine-phosphorylated Jak2 in UT-7/Epo cells in the absence of Epo and without phosphorylation of the Epo receptor (EpoR). Competition studies with C-terminal SHP-1 and Jak2 peptides decreased the amounts of SHP-1 and Jak2 detected in immunoprecipitates supporting the specific coprecipitation of SHP-1 and Jak2. In the presence of a recombinant GST-fusion protein containing both the N-terminal and C-terminal SH2 domains of SHP-1, anti-GST precipitated the fusion protein but not cellular Jak2. These studies suggest that SHP-1 and Jak2 are constitutively associated in UT-7/EPO cells. The association is not dependent upon Epo and is not mediated via SHP-1 SH2 binding. Sequential double immunoprecipitation demonstrated that only a small portion of intracellular Jak2 and SHP-1 molecules are constitutively associated. This partial association pattern may allow a more flexible and diverse regulation of Jak2 and SHP-1 activities. Whether Jak2 and SHP-1 are directly associated with each other or are part of a larger complex needs further investigation.

Spontaneously relapsing clonal, mucosal cytotoxic T-cell lymphoproliferative disorder: case report and review of the literature

Primary T-cell lymphoma of the gastrointestinal tract is a rare and usually aggressive disorder that may be associated with celiac disease. The authors describe a unique case of a clonal proliferation of CD8+ T cells involving the oral mucosa, ileum, and colon of a 35-year-old man that has regressed spontaneously and recurred numerous times over a 9-year period without treatment. The patient's symptoms were limited to occasional rectal bleeding and recurring painful oral ulcers. Within the intestine, these collections of small T cells induced minimal architectural distortions and did not show extensive epitheliotrophism. Polymerase chain reaction and sequencing analyses revealed that the identical T-cell clone has been present for more than 9 years and in different mucosal locations in this patient. This may represent a unique T-cell lymphoproliferative process akin to a mucosal counterpart of lymphomatoid papulosis of the skin.