Transcranial magnetic stimulation

We investigated the effects of unilateral cold-water vestibular stimulation on healthy subjects' performance in two cognitive tasks known to be differentially mediated by the two cerebral hemispheres. In a first experiment (right-hemisphere task), subjects memorized object-location associations while being stimulated with cold water in the left ear or right ear or not at all (control group). In the second experiment (left-hemisphere task), subjects memorized a list of sequentially presented function words while being stimulated in the same manner as the subjects in the first experiment. A recall phase followed each encoding phase. In the first experiment, subjects who had been stimulated in the left ear recalled the object locations significantly faster than subjects who had been stimulated in the right ear and those in the control group. The second experiment yielded the reverse pattern: correct word recognition was faster for subjects who had been stimulated in the right ear than for subjects stimulated in the left ear and those of the control group. We suggest that unilateral caloric stimulation leads to a selective activation of contralateral cerebral structures and speeds up cognitive processes mediated by these structures. These results are discussed with respect to findings in neglect patients and functional-imaging studies in healthy subjects.     

Activity-dependent control of bulk endocytosis by protein dephosphorylation in central nerve terminals

Bulk endocytosis is the process by which nerve terminals retrieve large amounts of synaptic vesicle membrane during periods of strong stimulation intensity. The process is rapidly activated and is most probably calcium dependent in a similar manner to synaptic vesicle exocytosis. This article briefly summarizes the current knowledge of bulk endocytosis with respect to its activation, kinetics and molecular mechanism. It also presents recent data from our laboratory showing that the dephosphorylation of a group of endocytosis proteins called the dephosphins by the Ca²⁺-dependent protein phosphatase calcineurin is key to the activity-dependent stimulation of the process. Possible downstream effectors of calcineurin are discussed such as the large GTPase dynamin I and its phosphorylation-dependent interaction partner syndapin I.     

Characterization of the dominant autoreactive T-cell epitope in spontaneous autoimmune haemolytic anaemia of the NZB mouse

NZB mice spontaneously develop autoimmune haemolytic anaemia (AIHA) due to a T helper-dependent autoantibody response against the erythrocyte anion channel protein, Band 3. Here, we characterize the recognition of the Band 3 sequence 861-874, which carries the dominant, I-E(d)-restricted T cell epitope. The ability of N and C-terminal truncated versions of peptide 861-874 to elicit NZB splenic T-cell proliferation indicated that the core epitope spans residues 862-870. Next, a set of alanine substitution analogues was tested to determine which residues functioned either as MHC anchor or TCR contact residues. A combination of proliferation and MHC:peptide binding assays identified residues 862(L), 864(V), 865(L), and 869(K) as I-E(d) anchor residues, and 868(V) as the only TCR contact residue. The ability of the wild-type sequence 861-874 to compete with a high affinity reference peptide for binding to I-E(d) indicates that the escape of pathogenic NZB T cells from purging of the autoreactive repertoire cannot be attributed to ineffective presentation of peptide 861-874 by its restricting element. It will now be possible to design altered peptide ligands of Band 3 861-874, in order to further dissect the mechanisms responsible for the maintenance and loss of T cell tolerance to RBC autoantigens, and to modulate the immune response in AIHA.     

A survey of bacterial diversity in ticks,lice and fleas from Australia

We isolated bacteria from ticks, lice and fleas. Partial small subunit rRNA sequences were obtained for each isolate and the closest matches in the FastA database were determined. These bacteria were mostly Gram-positive (Firmicutes), although representatives from the Proteobacteria (alpha, beta, gamma subdivisions) and CFB group were also isolated. Most of the isolates we found were from genera that were present in most of the ectoparasites studied, but a few genera were restricted to one species of ectoparasite. The most commonly isolated genera were Stenotrophomonas, Staphylococcus, Pseudomonas, Acinetobacter and Bacillus. Species of Bacillus and Proteus, which have biopesticide potential, were found in some of these ectoparasites. Overall, the communities of bacteria were similar to those found in other studies of parasitic arthropods.     

Staphylococcal toxin-induced T cell proliferation in atopic eczema correlates with increased use of superantigen-reactive Vbeta-chains in cutaneous lymphocyte-associated antigen (CLA)-positive lymphocytes

Staphylococcal superantigens have been implicated in the pathogenesis of atopic dermatitis (AD). This may occur through superantigenic activation of T lymphocytes and their subsequent induction of the skin homing receptor CLA on activated cells. We investigated the proliferative responses of peripheral blood mononuclear cells (PBMC) from 10 patients with an infective exacerbation of AD and six normal controls to the staphylococcal superantigens, staphylococcal enterotoxin A and B (SEA, SEB) and toxic shock syndrome toxin-1 (TSST-1), and the mitogens phytohaemagglutinin (PHA) and concanavalin A (Con A). We also assessed CLA and T cell receptor (TCR) Vbeta-chain expression by immunofluorescence and flow cytometry before and after stimulation. PBMC from AD patients showed two-fold increased proliferation to SEA and SEB (P < 0.01) compared with normals, whereas the response to mitogenic stimulation was identical. Analysis of (TCR) Vbeta-chain expression demonstrated increased use of superantigen-reactive Vbeta families in freshly isolated PBMC in AD patients compared with controls. This pattern of Vbeta-chain expression was only observed in the CLA+ but not the total population of T cells. Furthermore, there was a positive correlation between the enhanced PBMC proliferative response and increased expression of superantigen-reactive Vbeta families in atopic patients. These data support the concept that superantigens are important in the pathogenesis of this common condition, and also provide evidence that the increased use of certain Vbeta families in circulating, CLA+, skin homing lymphocytes is of functional significance.     

The development ofAmblyomma americanum andDermacentor variabilis (Acari: Ixodidae) fed on rabbits immunized with tick hemolymph

The possibility of interfering with the normal function of tick hemolymph using antihemolymph antibodies taken in with the bloodmeal, was investigated. Cell free hemolymph from repleteAmblyomma americanum andDermacentor variabilis ticks was used to immunize rabbits. Immunized rabbits developed high antihemolymph antibody titers (ca. 10⁵) and had no ill side effects. Rabbits were simultaneously infested with larvae, nymphs, and adult ticks. The biological performance of ticks fed on immunized rabbits was virtually identical to that of ticks fed on nonimmunized rabbits. Usually, the mean engorgement weights of nymphs and females and the weights of the egg masses of both species were slightly higher for ticks fed on the nonimmunized rabbits but differences were not significant (P>0.05) due to a large standard deviation. The possibility of deactivating a single hemolymph component with specific antibodies is discussed.Journal article 4979 of the Agricultural Experiment Station, Oklahoma State University, Stillwater, OK, USA     

Atmungserregung und zentrale Erregbarkeit bei Ventilationsstörungen der Lunge und bei respiratorischer Acidose

Zusammenfassung Atemphysiologische Untersuchungen an 19 Patienten mit Ventilationsstörungen der Lunge mit dem Atmungsanalepticum Micoren ergeben eine Ventilationssteigerung um 60% des Ausgangswertes, eine Abnahme der arteriellen CO₂-Spannung und eine Zunahme des Blut-p_H, somit eine ventilationsbedingte Verschiebung der Blutgase in Richtung einer relativen respiratorischen Alkalose. Im Mittelpunkt der Untersuchung steht die Frage einer über die Atmungserregung hinaus bei der respiratorischen Acidose und Atemdepression erzielbaren Erregbarkeitsänderung der Zentren. Im Gegensatz zu Patienten ohne respiratorische Acidose läßt sich bei Kranken mit respiratorischer Acidose eine Steigerung der Erregbarkeit auf CO₂-Reiz und eine wahrscheinlich begrenzte Verzögerung der unter O₂-Atmung drohenden zentralen Depression nachweisen. Indikationen und klinische Gesichtspunkte einer medikamentösen Atmungserregung werden unter besonderer Berücksichtigung der respiratorischen Acidose besprochen.Mit freundlicher Unterstützung der Deutschen Forschungsgemeinschaft.     

Autistic Traits,Empathizing–Systemizing,and Gender Diversity

Archives of Sexual Behavior - Previous research indicates a link between autism and transgender and gender-diverse identities, though the association is not yet fully understood. The current study...