Experimental electrocoagulation of dog esophageal and duodenal mucosa

The per review system for the assessment of research proposals is widely respected by working scientists. Nevertheless two problems associated with the operation of this system by the US National Institutes of Health are identified. First the scientist has no control over which committee will review an application and it may be considered by a quite inappropriate group. Second analysis of the committee composition suggests that in some of the groups several members are not active scientists and therefore not the "peers" of the applicant.     

Modulation of T cell and monocyte function in the spleen following infection of pigs with African swine fever virus

Infection of pigs with many strains of African Swine Fever Virus (ASFV) has been shown to cause a loss or marked decrease in the ability of splenocytes to respond to mitogens. These observations have been extended by cell fractionation and reconstitution experiments to show that the mitogen stimulated proliferative capacity of both the CD4+ and CD8+ T cells is affected. Similarly, monocytes which are directly infectable by virus, are functionally defective as antigen presenting cells when added to mitogen stimulated normal T cells. Interestingly, the same T cells which respond poorly in mitogenic assays can be activated by stimulation through the CD3 receptor. In contrast to the defective mitogenic response of T cells, B cell function, as assessed by stimulation through the CD40 ligand in vitro remains intact. There is no evidence for apoptosis in either the T cells or the B cells recovered from the spleens of ASFV infected animals 1-5 days following infection. Although the number of leucocytes which can be recovered from the infected spleen decreases rapidly with progression of the disease, the proportion of the different cell phenotypes remains constant. Thus decreased activity of lymphocytes in lymphoid tissue from ASFV infected animals appears to be directly attributable to infection of the monocytes.     

Neural parameters contributing to temperature compensation in the flight CPG of the locust, Locusta migratoria

Elevated thoracic temperature increases the wingbeat frequency of flying locusts. We investigated the extent to which temperature-induced changes in resting membrane potential and postsynaptic potential amplitude contribute to the effects of increased temperature on the frequency of the central flight rhythm. Flight neurons were hyperpolarized by changing the K+ concentration of the superfusing saline from 10 mM to 2 mM. 5 min of low-K+ superfusion hyperpolarized flight motoneurons from -42.8 mV to -50.1 mV with a concomitant decrease of the frequency of the central flight rhythm from 11.6 Hz to 10.5 Hz. The amplitude of postsynaptic potentials was halved after 10 min of zero Ca2+/high Mg2+ superfusion, but the frequency of the central rhythm did not change significantly. GABAergic inhibitory connections were reduced in amplitude using picrotoxin. This treatment increased the frequency of the central rhythm from 11.6 Hz to 12.9 Hz, and increased the thermosensitivity of the rhythm frequency. We conclude that the excitatory effect of increased temperature on rhythm frequency is not mediated by temperature effects on membrane potential and/or synaptic potential amplitude. We propose that the inhibitory effect of temperature-induced hyperpolarization of the membrane potential compensates for the excitatory effect of temperature on rhythm frequency (e.g. via increased conduction velocity). We further suggest that some measure of temperature compensation is afforded by equal effects on the amplitudes of excitatory and inhibitory postsynaptic potentials, such that the net effect on the level of excitation is zero.     

Transient central hypothyroidism as a cause of failure to thrive in newborns and infants

The course of two neonates and one 4-month-old infant with laboratory and clinical evidence of central hypothyroidism is described. All three presented with failure to thrive and improved after L-T4 therapy. Early recognition and treatment of newborns and infants with central hypothyroidism is important to maximize the potential for growth and development. Two of the three infants have been documented to have transient central hypothyroidism of hypothalamic origin, not previously reported.     

Memorizing and recalling spatial-temporal patterns in an oscillator model of the hippocampus

We describe the model of the hippocampus consisting of interactive oscillators with input from the entorhinal cortex (modulating the main information flow by a theta rhythm) and the septum (a theta rhythm generator). When interconnections between oscillators are allowed to strengthen in an adaptive way, the network can be trained using a series of lessons. This results in a connection matrix that memorizes the temporal sequence of inputs. Presenting one of the lessons to the trained network results in reproduction of the remainder of the sequence. In this paper, we create such a connection matrix, derive from it an appropriate Markov chain and simulate the chain to illustrate its dynamics.     

Mild traumatic brain injury--the Fife perspective

Excretion was studied of catecholamines and diphenilamine (DOPA) in 310 patients with carcinoma of the stomach and large intestine and 43 patients with non-malignant diseases. The oncological patients showed decrease in activity of the mediator link of the sympathoadrenal system (SAS) as well as its reserves but there was no association with sex, age, location or histological structure. Three types of SAS functioning were identified, such as compensation, overstrain and emaciation. Surgical intervention led to activation of the hormonal link and exhaustion of the system's reserves. Two kinds of sympathoadrenal response to stress were described--adequate and inadequate. In the former type, phases of stress remain as they are, unchanged, as are time periods of formation thereof, while under the latter one time periods of the phases formation or formation thereof get disordered.     

Experimental Investigations on Microstructure,Properties and Workability Behavior of Zinc Oxide Reinforced Al–Si–Mg Matrix Composites

Silicon - Al-Si based alloy matrix composites are now broadly utilized by the industrial sectors like automobile, structural, aerospace and more practical industrial applications due to its...     

Solution structure of acidic fibroblast growth factor bound to 1,3, 6-naphthalenetrisulfonate: a minimal model for the anti-tumoral action of suramins and suradistas

Recent data show that anti-angiogenesis may provide a promising route to treat cancer. Fibroblast growth factors (FGFs) are powerful angiogenic polypeptides, whose mitogenic activity requires the presence of heparin-like compounds. It has been shown that angiogenesis promoted by FGFs on inhibition by monoclonal antibodies and antisense targeting can also inhibit tumour growth. Derivatives of suramin, a polysulfonated binaphthyl urea and binaphthylsulfonated derivatives of distamycin, suradistas, constitute an important group of potential anti-cancer agents. These compounds compete with heparin in forming tight complexes with FGFs. This inhibits the recognition of these growth factors by their tyrosine kinase membrane receptors thereby suppressing their angiogenic activity. Here we show that 1,3,6-naphthalenetrisulfonate, a common chemical function of the suramins and suradistas with the highest anti-angiogenic activity inhibits the mitogenic activity of acidic fibroblast growth factor, and that this inhibition is relieved by increasing concentrations of heparin in the assay. We have also solved the three-dimensional structure in solution of the protein complexed to this compound. The structural data provide clues that may help in understanding the inhibitory effect of suramins and suradistas, and could contribute to the development of new anti-tumoral drugs.