The effect of oxidative stress on structural transitions of human erythrocyte ghost membranes

The influenza virus hemagglutinin (HA) contains three highly conserved cysteine residues at positions 551, 559, and 562 close to the carboxyl-terminus of the HA2 subunit which serve as palmitylation sites. Wild-type HA of influenza virus A/FPV/Rostock/34 (H7N1) and HA permutated by exchange of the acylated cysteine to serine residues were expressed in CV-1 cells by a SV40 vector system. Since density of immunostained HA on the cell surface measured by flow cytometric analysis did not differ between wild-type and acylation mutants, it was possible to compare acylation mutants and wild-type HA for their capacity to induce membrane fusion at low pH. The following observations were made: (1) lateral diffusion of a lipid-like fluorophore (R-18) from the erythrocyte membrane to the plasma membrane of cells expressing HA on the surface occurred equally well with mutants and wild type. (2) Diffusion of a low-molecular-weight fluorescent water-soluble probe (calcein) from erythrocytes into the cytoplasm of HA-expressing cells was not altered either. (3) However, depending on the position and the number of the deleted acylation sites, the mutants showed a reduced ability to induce syncytia. The data indicate that deacylation of the cytoplasmic tail has no measurable effect on the capacity of HA to induce membrane fusion and pore formation but that it suppresses syncytia formation.     

Intracellular study of interaction of paired-pulse facilitation and late phase of hippocampal long-term potentiation]

Presynaptic paired-pulse facilitation (PPF) rate decreased in most CA1 pyramidal neurones following the long-term potantiation (LTP) induction. The decrease correlated with the LTP magnitude as well as with the initial (pretetanic) PPF rate. The data obtained suggests an involvement of presynaptic mechanisms in maintaining the early and the delayed LTPs.     

The capacitance function of vessels of the anterior vena cava region during depressor stimulus effects on the blood circulation system]

Depressing neurogenic and humoral (acetylcholine, papaverine and histamine) effects against the background of dilatation of arterial vessels were shown to exert different results: the former stimuli led to blood output from the veins, whereas humoral stimuli enhanced the depot role of the veins in animals. The smallest possible doses of acetylcholine did sometimes reduce the vessels' capacity.     

Low prevalence of the ret/PTC3r1 rearrangement in a series of papillary thyroid carcinomas presenting in Belarus ten years post-Chernobyl

Many neurosurgeons prefer to use intraoperative computed tomographic (CT) scanning, when possible, to check whether there is residual lesion or unexpected bleeding. We report a practical intraoperative CT imaging system using a high-speed CT scanner installed in the operating room along with a digitally controlled neurosurgical operating table. We designed a rail-track system to mobilize the CT gantry. The gantry is fixed onto a motorized carrier that can be moved smoothly on a rail-track embedded in the floor and with a maximum reach of 2.85 m from the room's wall to the operating table. The longitudinal motion of the operating table is easily adjusted by a foot switch from manual control to automatic control directly from the CT scanner's computer like an ordinary CT scanner bed in increments of 2, 5 or 10 mm during CT scanning. Either a carbon-made radiolucent head frame or carbon-made head plate is used as a headrest. Using this CT scanner system, pre- and intraoperative CT scannings were performed on 46 patients with brain tumors, cervical lesions or other intracranial lesions. We could operate on the patient with enough working space between the mobile CT gantry and the operating table for microneurosurgery. We could obtain intraoperative CT imaging of a patient on the operating table while the surgical wound remained open, the surgical drapes kept in place, and the surgical position unchanged, saving time in intraoperative CT scanning and preparation for further surgery when needed. This intraoperative CT imaging system installed in the operating room should be useful for neurosurgery.     

Evaluation of fine needle capillary sampling in superficial and deep-seated lesions. An analysis of 670 cases

The gene rafY from the plasmid pRSD2, which enables Escherichia coli to grow on raffinose, was transferred into expression plasmid pUSL77. The protein was expressed in the porin-deficient Escherichia coli strain KS26 and was isolated and purified to homogeneity. The pure protein was reconstituted into lipid bilayer membranes. It formed an ion-permeable channel with a single-channel conductance of 2.9 nS of the open state in 1 M KCl, which is approximately twice of that of the general diffusion pores OmpF and OmpC of E. coli outer membrane. At lower pH the channel exhibited rapid flickering between three substates of the open channel. The RafY channel appears to be wide and water filled and has a small selectivity for cations over anions. Although RafY is part of an uptake and fermentation system for raffinose it does not contain a binding site for carbohydrates. Our results suggest that RafY is a general diffusion pore with a diameter, larger than that of the general diffusion porins OmpF and OmpC, that allows the diffusion of high-molecular-mass carbohydrates through the outer membrane.