Search for an endogenous ligand for sigma receptors

Whether there is an endogenous ligand for sigma receptors remains unknown. A total lipid fraction was isolated from the porcine liver, which was then subjected to chromatographic separation, yielding nine chromatographic fractions eluated at various chloroform/methanol ratios: each fraction was tested for its capacity of inhibiting the binding of (+)-[3H]SKF 10047 to hepatic sigma-receptors. The chromatographic fraction 7 + 7A (eluated at chloroform/methanol ratios of 60:40-10:90) which consisted mainly of phospholipids was found to have the highest activity. However, a complex analysis of this fraction revealed no relationship of its sigma-inhibiting activity to phospholipids. It is suggested that the non-competitive inhibition of (+)-[3H]SKF 10047 binding by the isolated active fraction is due to its presence of an endogenous ligand which, interacting with sigma-2 receptor, allosterically inhibits the binding of the labelled (+)-benzomorphan.     

Effect of reproduction of the LPP-3 cyanophage on glutamate dehydrogenase and glutamine synthetase activity in the cyanobacterium Plectonema boryanum

The effect of cyanophage LPP-3 reproduction on glutamate dehydrogenase and glutamine synthetase (GS) in P boryanum cells have been studied. It was determined that the both reactions are intensified by 135% and 220%, accordingly. Isoenzymes of GS were purified from native and infected cell of cyanobacteria. Their physical-and-chemical properties are different. The cyanophage development probably causes specific modification of the cell enzymes.     

Public health at the municipal level

The purposes of health protection and fortification in various sociums and conditions of attaining these purposes may differ at various levels (federal, regional and municipal) of the society organization. At the municipal level the fortification and protection of population health may be regarded as the chief idea, aim, and criterion of the optimal functioning and development of a socium of the given level, reflecting the measure of efficacy of providing the immediate vital activity of the population. The task of social management is as follows: the share of the national output, created by the socium, is to be distributed so that it were possible for this socium to permanently recreate and maintain at a certain qualitative level its labor resources--the major energy potential of the socium, and adequately provide and guarantee human rights as the main value of the society. A logistic model of the management structure ensuring population health at a municipal level is presented. For health control and for attaining this aim it is necessary to transfer the maximum of legal functions to the municipal level of society administration. It is desirable that every citizen, and not only administration, be involved in the reformation of the society as regards health protection, and that the citizens be personally interested in this process.     

Selective activation of Ca2+-activated K+ channels by co-localized Ca2+ channels in hippocampal neurons

Calcium entry through voltage-gated calcium channels can activate either large- (BK) or small- (SK) conductance calcium-activated potassium channels. In hippocampal neurons, activation of BK channels underlies the falling phase of an action potential and generation of the fast afterhyperpolarization (AHP). In contrast, SK channel activation underlies generation of the slow AHP after a burst of action potentials. The source of calcium for BK channel activation is unknown, but the slow AHP is blocked by dihydropyridine antagonists, indicating that L-type calcium channels provide the calcium for activation of SK channels. It is not understood how this specialized coupling between calcium and potassium channels is achieved. Here we study channel activity in cell-attached patches from hippocampal neurons and report a unique specificity of coupling. L-type channels activate SK channels only, without activating BK channels present in the same patch. The delay between the opening of L-type channels and SK channels indicates that these channels are 50-150 nm apart. In contrast, N-type calcium channels activate BK channels only, with opening of the two channel types being nearly coincident. This temporal association indicates that N and BK channels are very close. Finally, P/Q-type calcium channels do not couple to either SK or BK channels. These data indicate an absolute segregation of coupling between channels, and illustrate the functional importance of submembrane calcium microdomains.     

The role of antibiotics in the treatment of periodontitis (Part 2--Controlled drug delivery)

Since last reviewing the field, controlled release products have made the jump from research to clinical practice. The potential to extend the efficacy of periodontal therapy with such products is exciting, but also needs careful evaluation. This review will look at recent developments and also will examine the eventual place for these products in periodontics.     

Radionuclide studies in intestinal transplantation. Diagnosis of rejection and assessment of permeability

Three patients who received intestinal allografts were studied using two distinct radionuclide investigations. In the first, 111In or 99mTc-labeled leukocyte scanning was performed to assist in the diagnosis of rejection. It was able to demonstrate the occurrence of rejection in the transplanted intestine, and the response to antirejection therapy. In 1 case, the abnormality on the scan preceded the histological confirmation of rejection. The second technique studied mucosal integrity by serial 51Cr-EDTA/14C-mannitol permeability tests. These studies demonstrated the initial marked impairment and the slow return to normal function of the intestinal mucosal barrier. In 1 patient, this occurred by 91 days; in another, it took 232 days. A single assay performed in the third patient at the time of allograft rejection was also abnormal. Both radionuclide tests were helpful in the care of these complicated cases.