Viral hemagglutinin augments peptide-specific cytotoxic T cell responses

In attempt to increase the induction of peptide-specific cytolytic T cells (CTL) we investigated the effect of the Newcastle disease virus (NDV) hemagglutinin-neuraminidase (HN) gene product on the activation of peptide-specific CTL. Spleen cells of CH3 mice immunized against the influenza nucleoprotein peptide 50–63 (NP 50–63) were restimulated in vitro (i) with peptide-pulsed syngeneic fibroblast cells (Ltk^?) as antigen-presenting cells, which were in addition (ii) infected with NDV or (iii) stably transfected with the HN cDN A of NDV. A greater than sixfold increase in peptide-specific CTL responses was observed in cultures restimulated with peptide-pulsed Ltk^? cells which co-expressed viral hemagglutinin due to either infection or transfection. A similar augmentation was seen in CTL responses against other types of antigen (major histocompatibility complex alloantigens, minor histocompatibility antigens or tumor antigens) when suboptimal cultures were stimulated with the respective antigen-presenting cells modified by NDV infection. These findings suggest that NDV or viral HN expressed on antigen-presenting cells or tumor cells can exert a T cell co-stimulatory function.     

Culture-negative Bartonella endocarditis in a patient with renal failure: the value of molecular methods in diagnosis

Members of the genus Bartonella are increasingly recognised as a cause of culture-negative endocarditis, particularly in those patients with underlying risk factors (e.g., homelessness and alcoholism (B. quintana) or valvulopathy and cat ownership (B. henselae). The aortic and mitral-valves are most commonly involved. Here, a case is reported of culture-negative right-sided endocarditis, without any of the above risk factors, due to Bartonella sp. in a 69-year-old man who presented with acute renal failure. The diagnosis was made using a broad-range 16S rRNA polymerase chain reaction (PCR) technique and direct automated sequencing on a peripheral blood sample, which was subsequently confirmed serologically. A review of the literature on Bartonella endocarditis is also presented. Molecular laboratory methods using peripheral blood or blood cultures may be very useful in the diagnosis of causal agents in culture-negative endocarditis and add further support to the recently inclusion of molecular (PCR) diagnosis, as a major Duke's criterion, for the diagnosis of infective endocarditis.     

Rapid discrimination of Mycobacterium tuberculosis strains by random amplified polymorphic DNA analysis.

Investigations of the epidemiology of tuberculosis have been hampered by the lack of strain-specific markers that can be used to differentiate isolates of Mycobacterium tuberculosis. We report the development of a rapid protocol for random amplified polymorphic DNA analysis which included the use of a commercially available DNA extraction kit (GeneReleaser). This was applied to 14 strains of M. tuberculosis, including strains associated with temporal and geographical clusters of tuberculosis in the United Kingdom and those from India, Africa, and Saudi Arabia. Strains of M. tuberculosis could be discriminated in about 8 h by this method, which is therefore a rapid and simple alternative to restriction fragment length polymorphism analysis.     

Monitoring exocytosis from single mast cells by fast voltammetry

We have used fast differential ramp voltammetry with carbon-fibre electrodes to monitor exocytotic secretion in single rat mast cells. The oxidation peak and other aspects of the electrochemical profile of the substance released were similar to those of 5-hydroxytryptamine (5-HT) and the signals were increased by preloading the secretory granules with exogenous 5-HT. Metabolic blockade inhibited both visible degranulation and the electrochemical signal. For comparison, quinacrine, which is fluorescent and accumulates in secretory vesicles, was used as an alternative means of detecting secretion in single cells. The amplitude of the electrochemical signals observed during degranulation correlated well with the loss of quinacrine fluorescence. Both methods were used to record successive rounds of secretion in single mast cells in response to repeated applications of compound 48/80.     

The Effects of Perceived Stress on Reactions to Messages Designed to Increase Health Behaviors

This study examined the impact of perceived stress on responses to messages that encouraged the performance of health promotion and disease detection behaviors. It was hypothesized that increases in perceived stress would be associated with decreased processing of messages encouraging disease detection behaviors, and that increases in perceived stress would not effect the processing of messages encouraging health promotion behaviors. To test these hypotheses participants completed a perceived stress measure and then read a message that encouraged the performance of either a health promotion or a disease detection behavior. Then the participants were asked to indicate their agreement with the message and to attempt to recall the message. The results indicated that participants experiencing higher levels of perceived stress spent less time reading and recalled less of the messages about detection behaviors than of the messages about promotion behaviors. When participants were experiencing lower levels of perceived stress these differences disappeared.

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GABAB receptor transduction mechanisms, and cross-talk between protein kinases A and C, in GABAergic terminals synapsing onto neurons of the rat nucleus basalis of Meynert

The transduction mechanisms underlying presynaptic GABA_B receptor-mediated inhibition of transmitter release have been characterized for a variety of synapses in the central nervous system (CNS). These studies have suggested a range of transduction mechanisms, including a role for second messengers such as protein kinases A (PKA) and C (PKC). In the present study, we have examined the intracellular signalling pathways underlying baclofen-induced inhibition of GABA release from terminals synapsing onto rat basalis of Meynert neurons using patch-clamp recordings. Baclofen, a selective GABA_B receptor agonist, reversibly decreased both evoked and spontaneous, miniature, GABAergic inhibitory postsynaptic currents (eIPSCs and mIPSCs, respectively). Such baclofen actions were completely abolished by CGP55845A, a selective GABA_B receptor antagonist, and by staurosporine, a non-selective PKA and PKC inhibitor. The mIPSC frequency was still decreased by baclofen even in the presence of 4 AP, a K⁺ channel blocker, and Cd²⁺, a voltage-dependent calcium channel blocker. Pharmacological activation or inhibition of PKC activity affected basal GABA release and mildly affected the response to baclofen. Inhibition of the cAMP/PKA cascade also affected basal GABA release and, in a subset of neurons, occluded the effects of baclofen, suggesting that the GABA_B receptor-mediated inhibitory action on GABA release was mediated via decreases in PKA activity. In addition, PKA inhibition occluded the effects of PKC modulation on both basal GABA release and on the response to baclofen. Our results characterize the transduction pathway of baclofen at these nucleus basalis of Maynert (nBM) synapses and show, for the first time, some cross-talk between the cAMP/PKA and PKC pathways in mammalian presynaptic nerve terminals.     

Modulation and function of caspase pathways in B lymphocytes

Summary:  During their development, B-lineage cells are selected to mature, to die, to divide, or to survive and wait, ready to respond to external signals. The homeostatic balance between growth, death, and survival is mediated by signaling pathways through the B-cell antigen receptor (BCR) complex, cytokine and chemokine receptors or cell–cell coreceptor interactions. The BCR complex is a master regulator essential at key checkpoints during development. These checkpoints involve various processes, including negative selection (deletion), anergy, receptor editing, and positive selection. Without BCRs or downstream BCR-signaling components, B-lineage cells arrest during development. Removal of BCRs from mature B cells leads to their death. Here, we discuss signaling pathways in B cells that activate members of the caspase family of cysteine proteases. In some B-cell subsets, BCR signaling activates caspases, which in turn induce a program leading to cell death. However, in other contexts, caspases are involved in the proliferation of B cells. The outcome depends in part on the presence or absence of modifiers that affect signaling thresholds and on which caspases are activated. These mechanisms allow the coordinated regulation of proliferation and apoptosis that is essential for lymphoid homeostasis.     

Congenital coxa vara. A retrospective review

Forty-two cases of coxa vara were retrospectively reviewed. All 42 cases were classified based on their history and roentgenographic appearance. Twenty-two cases of true congenital coxa vara were identified and are the primary focus of this review. In this study we have introduced the Hilgenreiner epiphyseal (HE) angle as measured on standard AP roentgenograms of the hip. Retrospectively, this angle was measured to aid in deciding candidacy for surgery, as well as a means of determining the amount of surgical correction necessary to prevent a recurrence of the deformity. The indication for surgery should be an HE angle of greater than 60 degrees. HE angles of less than 60 degrees and greater than 45 degrees represent a "gray zone" and should be observed. HE angles of less than 45 degrees will generally correct spontaneously without surgery.     

The Feasibility of Using Computrition Software for Nutrition Research—A Pilot Study

We evaluated the feasibility of using Computrition to design and implement a low vs. typical sodium meal plan intervention for older adults. Dietitians used Computrition to design a 7-day meal plan with three caloric levels (≤1750, 2000, ≥2250 kcals/day) and two sodium densities (low = 0.9 mg/kcal; n = 11 or typical = 2 mg/kcal; n = 9). Feasibility was determined by post-hoc definitions of effectiveness, sodium compliance, palatability of diet, sustainability, and safety. Given the low number of participants in one of the three calorie groups, the higher calorie groups were combined. Thus, comparisons are between low vs. typical meal plans at two calorie levels (≤1750 or ≥2000 kcals/day). Overall, regardless of the calorie group, the meal plans created with Computrition were effective in reaching the targeted sodium density and were safe for participants. Furthermore, individuals appeared to be equally compliant and reported similar palatability across meal plans. However, one of the three criteria for the sustainability definition was not met. In conclusion, we successfully used Computrition to design low and typical sodium meal plans that were effective, compliable, and safe. Future studies of older adults in similar settings should focus on improving the palatability of the meal plans and scaling this protocol to larger studies in older adults.