Mycotic Aneurysm of Brachial Artery Secondary to Infective Endocarditis.

Introduction: This case describes a brachial artery mycotic aneurysm (BAMA) secondary to infective endocarditis caused by . BAMAs are rare and potentially limb or life threatening. A literature review revealed 61 cases since 1950, primarily caused by intravenous drug use, with being the most common causative bacteria.

Adult Burkitt's lymphoma presenting as intussusception: first UK case report.

Colonic intussusception is rare in adults and can present with non-specific symptoms that can make diagnosis difficult and delayed. Unlike in children, it is commonly due to a pathological lead point that is often malignant. This case is the first reported case of adult intussusception due to Burkitt's lymphoma in the UK.

Shape instability of a biomembrane driven by a local softening of the underlying actin cortex.

We present a theory showing that local shape instabilities of composite biological membranes, consisting of a lipid bilayer and an underlying actin cortex, can be triggered by a local softening of the membrane-associated cytoskeleton. A membrane containing such cortical defects can form blisters or invaginations, depending on external conditions. The theoretical predictions agree with observations provided by two sets of experiments: (i) microscopic observations of shape changes of giant vesicles with underlying shells of a thin actin network show the formation of local blisters and (ii) micropipet aspiration experiments of Dictyostelium discoideum cells in which we observed the formation of blisters in the aspirated cell part.

A micromechanic study of cell polarity and plasma membrane cell body coupling in Dictyostelium.

We used micropipettes to aspirate leading and trailing edges of wild-type and mutant cells of Dictyostelium discoideum. Mutants were lacking either myosin II or talin, or both proteins simultaneously. Talin is a plasma membrane-associated protein important for the coupling between membrane and actin cortex, whereas myosin II is a cytoplasmic motor protein essential for the locomotion of Dictyostelium cells.

Membrane bending modulus and adhesion energy of wild-type and mutant cells of Dictyostelium lacking talin or cortexillins.

We have employed an interferometric technique for the local measurement of bending modulus, membrane tension, and adhesion energy of motile cells adhering to a substrate. Wild-type and mutant cells of Dictyostelium discoideum were incubated in a flow chamber. The flow-induced deformation of a cell near its adhesion area was determined by quantitative reflection interference contrast microscopy (RICM) and analyzed in terms of the elastic boundary conditions: equilibrium of tensions and bending moments at the contact line.

Structural mosaicism on the submicron scale in the plasma membrane.

The lateral mobility of the neural cell adhesion molecule (NCAM) was examined using single particle tracking (SPT). Various isoforms of human NCAM, differing in their ectodomain, their membrane anchorage mode, or the size of their cytoplasmic domain, were expressed in National Institutes of Health 3T3 cells and C2C12 muscle cells. On a 6.

Transient confinement of a glycosylphosphatidylinositol-anchored protein in the plasma membrane.

Glycosylphosphatidylinositol (GPI)-anchored proteins participate in many cell surface functions; however, the molecular associations of these lipid-linked proteins within the plasma membrane are not well understood. Recent biochemical analyses of detergent insoluble membrane fractions have suggested that GPI-anchored proteins may be associated with glycosphingolipid (GSL)-enriched domains that also contain cholesterol and signaling molecules such as Src family kinases and, in some cases, caveolae. The movements of two components of the putative GSL-enriched domains, Thy-1, a GPI-anchored protein, and GM1, a GSL, were followed with single particle tracking on C3H 10T1/2 cell surfaces and categorized into four modes of lateral transport, fast diffusion, slow anomalous diffusion, diffusion confined to 325-370 nm diameter regions, and a fraction of molecules that was essentially stationary on the 6.

New insights into membrane dynamics from the analysis of cell surface interactions by physical methods.

The physical, chemical and mechanical properties of the cell surface can be probed using a variety of microscopy-based techniques. The movements of membrane components are currently being characterized, and recent experiments have begun to define the structural origins of these modes of transport at a molecular level. However, explicit relationships between new knowledge of membrane structure and complex, linked functions, such as signal transduction and adhesion, remain elusive.

Detection of temporary lateral confinement of membrane proteins using single-particle tracking analysis.

Techniques such as single-particle tracking allow the characterization of the movements of single or very few molecules. Features of the molecular trajectories, such as confined diffusion or directed transport, can reveal interesting biological interactions, but they can also arise from simple Brownian motion. Careful analysis of the data, therefore, is necessary to identify interesting effects from pure random movements.

Passive immunotherapy in the treatment of advanced human immunodeficiency virus infection.

To evaluate the safety and efficacy of passive immunotherapy for advanced human immunodeficiency virus (HIV) infection, a randomized, double-blind, controlled trial of human anti-HIV hyperimmune plasma was conducted. Sixty-three subjects with stage IV HIV disease (AIDS) were randomized to received 250 mL of either HIV-immune plasma or HIV antibody-negative plasma every 4 weeks. Although nonsignificant trends toward improved survival and delayed occurrence of a new opportunistic infection were noted, no significant effects on absolute CD4 lymphocyte counts or quantitative HIV viremia were seen.

The N2 component elicited by stimulus matches and multiple targets.

This paper examines two methodological issues concerning the N2 component of human event-related potentials. The first issue concerns the circumstance that the most common way to obtain N2 in discrimination tasks is with an infrequent deviant stimulus that mismatches a frequent, standard stimulus. In these studies it is not possible to disentangle the effects of stimulus probability and stimulus mismatch on N2.

Effects of the amount of stimulus information processed on negative event-related potentials.

Event-related potentials were recorded during simple reaction time and 3 discrimination conditions which varied in the amount of stimulus information that needed to be processed. It was found that NA became longer in duration as the amount of stimulus information that required processing was increased. Using sequential topographic mapping, it was concluded that there are at least 3 overlapping deflections that comprise NA.

Topography of visual event-related potentials during geometric and phonetic discriminations.

Event-related potentials (ERPs) were obtained to letters during 3 tasks that involved a SIMPLE RESPONSE (SR) to each letter presentation, a FORM discrimination of the letters that formed a closed loop, and a RHYME discrimination of the letters that rhymed with the letter 'v'. The first task only required detection of the letters, the FORM task required a visual-spatial analysis, and the RHYME task, a grapheme-phoneme conversion of the letters followed by a determination of rhyming characteristics. The SR ERPs were morphologically different from the discriminative ERPs, notably by the absence of N2 and P3.

Evoked potentials in the assessment of neurotoxicity in humans.

The present paper reviews strengths and weaknesses of evoked potentials (EPs) as an index of toxic insult to the nervous system. EPs are obtained by averaging successive samples of EEG time-locked to the presentation of stimuli. Components of the resulting waveform can be measured for amplitude, latency, and distribution.

Effects of expectation on negative potentials during visual processing.

ERPs were recorded during several RT tasks: simple RT; oddball choice RT; a LIE condition in which subjects were told stimuli would infrequently change, but did not; differential responding to two equiprobable stimuli that were randomized in one condition and alternated in another condition. Subtracting ERPs elicited during simple RT from those elicited during the other conditions, it was found that a negative component, NA, was enhanced, relative to simple RT, in all the other RT tasks. The data of the LIE condition indicated that NA was enhanced by the expectation that unpredictable stimulus changes would occur, even when they did not.

Manipulation of event-related potential manifestations of information processing stages.

The timing of two event-related potential components was differentially affected by two experimental variables. The earlier component (NA) was affected by degradation of the stimuli and the later component (N2) by the nature of a classification task. The results support the hypothesis that NA and N2 reflect sequential stages of information processing, namely, pattern recognition and stimulus classification.

An electrophysiologic indication of auditory processing defects in autism.

Averaged evoked potentials (EPs) to clicks, random pitch changes (signals), and random deletions of stimuli within a regular train of tones were examined in five autistic and five normal children. Brainstem auditory EPs were abnormal in one of the autistic patients. The early cortical EP components P60 and N100 showed no differences across groups, whereas the P200 component of the cortical responses to clicks, as well as the late positive component (P300) to the pitch changes and deleted stimuli, were significantly smaller in the autistic subjects as a group.

A brain event related to the making of a sensory discrimination.

Event-related potentials associated with detected targets in a vigilance task were analyzed in two ways: (i) by sorting the potentials in terms of sequential reaction time bins of 50 milliseconds and (ii) by examining the single trial waveforms. A negative component (N2) covaried in latency with reaction time. These results support the hypothesis that N2 reflects a decision process which controls behavioral responses in sensory discrimination tasks.

The scalp topography of potentials in auditory and visual discrimination tasks.

Averaged event-related cortical potentials (ERPs) were obtained from an array of scalp electrodes overlying the left hemicranium in response to regularly presented visual or auditory stimuli (non-signals)and to infrequent random replacements by different stimuli (signals) in the same modality. A motor response was required to the signals. Non-signal ERPs were subtracted from signal ERPs and the topographic distributions of the negative (N2 delta) and positive (P3 delta) components were plotted as isopotential maps.